GADL International Ltd Feasibility Study for Construction of a Bridge

Transcription

GADL International Ltd
Feasibility Study for Construction
of a Bridge between Malé and
Hulhumalé
Final Report
REP-217093-01
Issue | August 2011
Ove Arup & Partners Hong Kong Ltd
Level 5 Festival Walk
80 Tat Chee Avenue
Kowloon Tong
Kowloon
Hong Kong
www.arup.com
This report takes into account the particular
instructions and requirements of our client.
It is not intended for and should not be relied
upon by any third party and no responsibility is
undertaken to any third party.
Job number
217093
Feasibility Study for Construction of a Bridge between Malé and Hulhumalé
Final Report
Contents
Page
Executive Summary
i
1
Introduction
1
2
Project Context
2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
2.10
3
4
5
6
Malé
Hulhumalé
Ibrahim Nasir International Airport
Greater Malé
The Eye of Maldives
Funadhoo Island
Moon Bay Marina
Site Conditions
Key Issues
Key Stakeholders
2
3
5
6
6
7
7
8
11
14
Alignment Options
15
3.1
3.2
3.3
15
16
19
Alternatives Considered
Landing Points and Traffic Dispersal
Initial Sifting of Alignment Options
Airport Operational Issues
21
4.1
4.2
4.3
4.4
4.5
4.6
21
22
24
24
25
25
Airport Height Restrictions
Ground Transportation
Traffic Volume
Conflicts Between Road and Air Traffic
Airport Emergency Vessels
Conclusions
Navigation Issues
26
5.1
5.2
5.3
5.4
5.5
26
29
30
32
32
Marine Activity
Airdraft
Span and Marine Safety
Ship Impact
Conclusions
Environmental Issues
33
6.1
6.2
33
HULHUMALE BRIDGE FINAL REPORT.DOCX
Introduction
Environmental Legislation, Guidelines, Policies and
International Conventions
33
6.3
6.4
6.5
7
8
9
Final Report
Baseline Conditions
Potential Impacts and Mitigation Measures
Influence of Climate Change
36
40
45
Bridge Structure Options
46
7.1
7.2
7.3
7.4
7.5
46
48
52
53
55
Functional Cross Section
Structural Options (Alignment Option A)
Floating Bridge Option (Alignment C)
Operation & Maintenance
Appearance of the Bridge Options
Construction Cost Estimates
56
8.1
8.2
8.3
8.4
Methodology
Fixed Bridge on Alignment A
Floating Bridge on Alignment C
Operation & Maintenance Costs
56
56
56
57
Potential Financing & Revenue Models
58
9.1
9.2
9.3
9.4
9.5
58
60
61
62
63
Alternatives for Financing the Bridge
Sources of Revenue
Tolls
Payment in Kind
Conclusions
10
Comparison of Options
64
11
Conclusions & Recommendations for Further Study
65
References
Appendices
Appendix A
Drawings
Appendix B
Artistic Images
Final Report
Executive Summary
Introduction
GADL International Limited has commissioned Ove Arup & Partners Hong Kong
Ltd to carry out an initial feasibility study for the construction of a bridge between
the Malé and Hulhumalé Islands.
This feasibility study was commissioned on the 31st May 2011. After an initial
desk study, a site visit was carried out from 14th June to 16th June 2011. In
addition to inspection of the site and potential landing points, stakeholder
consultation meetings were carried out. After completion of the site visit, this
report has been prepared to present the findings of the initial feasibility study.
Alignment Options
Three different alignments have been studied and an initial sifting exercise was
carried out to determine the suitability of each alignment for different bridge types.
Bridge Type
Option A
Option B
Option C
Fixed Bridge
Considered further
Unsuitable ground
conditions – high risk
High cost and poor
functionality
Floating Bridge
Wave conditions are too rough – high risk.
Considered further
Alignment A is particularly favourable in terms of traffic dispersal on Malé and
should result in the least amount of congestion on the island. It is also favourable
in terms of allowing a direct connection to a future link to Villingili Island as part
of the long term goal of connecting the Greater Malé region.
To maintain safe operation of the airport there are restrictions on the height of
construction of the bridge which are very influential to the structural options that
can be considered for the bridge. In view of the deep water, fast currents and
ocean swells that are found in the Gaadhoo Koa, one option that could be
considered would be to construct a bridge from shore to shore without any
intermediate supports in the channel. However, this would require very tall towers
which would violate the height restrictions.
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In addition to these restrictions it is apparent that the construction of the bridge
will have an influence on the airport landside transport infrastructure system.
Although the airport masterplan already considers the scenario of the bridge being
constructed there may need to be further coordination between the airport
development and government plans for public transport and road infrastructure
between Malé and Hulhumalé.
Navigation Issues
The Maldives is an archipelago and marine traffic is an important aspect of
everyday life in the islands. Construction of a bridge across the Gaadhoo Koa will
have a significant influence on how vessels navigate around Malé, especially the
larger commercial vessels. However, due to the large number of entries into the
atoll it has been confirmed by key stakeholders that there will be no adverse
impact to marine operations if appropriate additional navigation aids are provided
for shipping using alternate channels.
All bridge options will provide sufficient airdraft for resort speedboats, local
ferries and the airport firefighting vessel to pass under the bridge.
Based on the available data it appears that the environmental impacts of the bridge
can be managed and mitigated.
Climate Change Resilience
Hulhumalé was built with a formation level 0.5m higher than Malé in order to
provide greater resilience to sea level rise. The bridge, which will promote the
development of Hulhumalé, will therefore be of benefit to the climate change
resilience of the nation.
The provision of a fixed link could also assist the nation in coping with some
effects of sea level rise, specifically:
•
Facilitating disaster relief efforts
•
Aiding with population mobility in view of shifting land use patterns
Traffic Congestion
There is a concern that the construction of the bridge could increase traffic
congestion on the islands. Ways in which congestion can be tackled could include:
•
Promoting public transport (buses) on the bridge
•
Selecting a landing point which provides good traffic dispersal in Malé
•
Implementing traffic improvements to facilitate dispersal
•
Restricting types of vehicle that are permitted to use the bridge
Employment in Ferry Sector
Although the construction of the bridge will bring economic benefits to the
majority of the population there is a concern that it will cause job losses for those
currently either directly or indirectly employed in ferry operations between Malé
and Hulhulé/Hulhumalé.
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It is possible that bus operations on the bridge could provide appropriate
reemployment and this could be promoted by
•
Retraining schemes (e.g. bus drivers licence, mechanics training etc.)
•
Trade-in scheme where the government could provide mini-buses in return for
ferries.
•
Direct intervention (employment quotas)
•
Toll structure on the bridge which promotes the use of buses
There would be some costs associated with these schemes but these would be a
small percentage in comparison to the overall project cost.
Three different options for the bridge structure have been illustrated in general
arrangement drawings and artistic images, two different fixed bridge alternatives
on alignment option A and a floating bridge on alignment option C.
Balanced cantilever bridge on Alignment A
Extradosed bridge on Alignment A
Floating bridge on Alignment C
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A top down estimate has been made based on historic construction costs of similar
projects calibrated or adjusted for features unique to the project
There are no historic projects of a similar nature in the Maldives. Therefore
historic construction costs for international projects need to be considered. The
adjustments that need to be made for features unique to this project are:
•
Construction in the Maldives where all materials need to be imported
•
Construction in deep water with weak and uncertain ground
Although material costs are relatively high in the Maldives, labour costs are
relatively low compared to the countries where suitable reference projects have
been identified. This has been taken into account in the cost adjustment.
The estimated cost of construction of the bridge is USD 70 to USD 100 million.
Based on government policy and current procurement trends in the Maldives it is
believed that an appropriate PPP structure is likely to be the best way of financing
the project.
The project is unlikely to be financially viable based solely on direct user fees
(tolls). Therefore alternative financing and revenue strategies are required. It is
likely that a successful strategy will combine the following elements:
•
Private partner builds the bridge and then maintains and operates it for a fixed
concession period (25 to 30 years)
•
Initial government capital contribution in the form of Viability Gap Funding
•
Additional Payment in Kind based on development rights / land leases for
commercial / high value residential property in Hulhumalé
•
Toll revenue collected by the private partner but respecting a pre-agreed toll
structure which promotes public transport on the bridge
It is worth noting that the economic benefits of a project such as this frequently
exceed the financial revenue that can be generated. This is because there are either
long term benefits which are beyond the time frame of a private investor or
because there are benefits which are associated with the project but for which a
direct user charge cannot be applied.
In this case, the quality of life benefits achieved by reducing urban congestion in
Malé and the enhanced climate change resilience by promoting development on
slightly higher ground are both significant benefits. Therefore the fact that the
project is not considered financially viable based on direct user fees should not be
taken to mean that the project is not worthwhile.
Conclusions & Recommendations for Further Study
All parties consulted were in favour of the construction of a fixed link to connect
Malé and Hulhumalé.
Construction of a bridge is feasible although there exist a number of significant
technical and financial challenges which must be overcome.
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This Feasibility Study was envisaged as an initial scoping study and was limited
by the time as well as the information available. In view of the anticipated
benefits of the project it is recommended that a Preliminary Design study is
carried out with the following objectives:
•
•
•
•
•
Gather additional data
Confirm technical details of the project
Assess the impacts of the project
Update cost estimates
Develop procurement model for the project addressing the financial
requirements
An approximate timeline for the project is given below. It would be possible to
slightly reduce the overall procurement timeline for the Design and Build / PPP
procurement route by integrating the scope of works of the Bid Process
Management into the Preliminary Design since this would allow prequalification
to start earlier.
In order to control costs at this early stage of project development it could be
possible to subdivide the Preliminary Design into two stages with the aim to limit
design and investigation costs in Stage 1:
•
Stage 1 - Conceptual design of options, update of cost estimates and selection
of preferred option
•
Stage 2 – Preliminary design, assessment of impact, further update of cost
estimates and development of procurement model
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Final Report
Introduction
The Government of the Republic of Maldives is interested to link various islands
in the Greater Malé region by construction of bridges.
GADL International Limited has commissioned Ove Arup & Partners Hong Kong
Ltd to carry out an initial feasibility study for the construction of one such bridge
between the capital Malé and Hulhumalé Islands. Hulumalé is connected to
Hulhulé (the airport island) by road alongside of the reef.
Malé is the capital and most populous city in the Republic of Maldives. It is
located at the southern edge of North Malé Atoll (Kaafu Atoll).
Ibrahim Nasir International Airport is the only gateway to Maldives and is located
on the Hulhulé Island which is 1km away from the capital, Malé.
A commercial harbour is located on Malé Island and is the heart of all commercial
activities in the country. Malé Island is heavily urbanized, with the built-up area
taking up essentially its entire landmass. Almost one third of the nation's
population lives in the capital city, and the current population of this island is over
100,000.
Currently the only mode of transportation between Malé and Hulhulé islands is by
boat / ferry. A link between the two islands by a bridge will make transport
between the islands easier for both public transportation and cargo movement.
This feasibility study was commissioned on the 31st May 2011. After an initial
desk study, a site visit was carried out from 14th June to 16th June 2011. In
addition to inspection of the site and potential landing points, stakeholder
consultation meetings were carried out with representatives of the following
organisations:
•
•
•
•
•
•
•
•
The President’s Office
Ministry of Housing and Environment
Maldives Ports Limited
Maldivian Coast Guard
Malé Water & Sewerage Company Pvt Ltd
Environmental Protection Agency
Housing Development Corporation
GMR Malé International Airport Pvt. Ltd
After completion of the site visit, this report has been prepared to present the
findings of the initial feasibility study.
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2
Project Context
2.1
Malé
Final Report
Malé Island is heavily urbanized, with the built-up area taking up essentially its
entire landmass. Slightly less than one third of the nation's population lives in the
capital city, and the population has increased from 20,000 people in 1987 to over
100,000 people today. Malé is the centre of all commerce, administration and
government institutions in the Maldives.
Figure 1 Aerial view of Malé Island (Source: Wikimedia Commons © Shahee Ilyas)
Since there is no surrounding countryside, all infrastructure has to be located in
the city itself. Water is provided from desalinated ground water; the water works
pumps brackish water from 50-60m deep wells in the city and desalinates that
using reverse osmosis. Electric power is generated in the city using diesel
generators. Sewage is pumped unprocessed into the sea. Solid waste is transported
to nearby islands, where it is used to fill in lagoons.
Figure 2 Progress of land reclamation up to 1992 (Source: [7])
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Reclamation of the lagoon on Malé has added more than half again to the original
land area of the island which now extends almost to the edge of the reef on all
sides except for the protruding submarine outer edge of the reef in the south east
corner of the island.
In February 2002 a reef slope collapse occurred on the north eastern corner of the
island, a solid jetty was destroyed and blocks and debris of the jetty fell down the
reef slope. An investigation was made of the engineering geology of the island
which concluded that there could be further potential slope failures on the critical
north eastern margin of the island.[11]
2.2
Hulhumalé
Reclamation of the 188 hectares of Hulhumalé began on October 16, 1997 on the
Hulhulé-Farukolhufushi lagoon 1.3 km off the north east coast of Malé. Initial
reclamation (or Phase I) consisting of 45% of land mass was carried out by the
Ministry of Construction and Public Works (MCPW) costing USD 11 million.
The project was then continued by a Belgian Joint Venture Company,
International Port Engineering and Management (IPEM) and Dredging
International (DI) costing an estimated USD 21 million. All the works involving
reclamation and coastal structure development covered in Phase I was completed
by June 2002.
Development of Hulhumalé is masterminded by the government owned Housing
Development Corporation (HDC). Originally solely responsible for the
development and management of Hulhumalé the corporation is now mandated to
undertake government housing projects not only in Hulhumalé but elsewhere in
the Maldives as well. Its mission now is to relieve the urban congestion in the
Maldives by providing housing in a socially responsible and commercially viable
manner.
HDC’s main focus currently remains in developing Hulhumalé into a unique
island city in the North Malé Atoll, while creating opportunities for better homes,
health, employment and education services in the Maldives. HDC has three roles
in the development of Hulhumalé.
•
Firstly, it acts as a master developer, delivering the vision, inspiration and
imagination of the project in a manner that is feasible and commercially viable.
•
Secondly, HDC is a builder, investing in the infrastructure necessary for
quality living and business prosperity. These include the development of roads,
landscaping, and ensuring that basic utilities as well as other essential services
are available for investors and residents.
•
Lastly, HDC acts as regulator, overseeing detailed planning, architectural
guidelines and building regulations.
HDC deals with the lease and sale of land as well as developed property on
Hulhumalé. The company focuses on three broad areas of real estate development:
residential, commercial, and industrial.
Primary developments in terms of the required physical and social infrastructure
and residential developments were completed in 2004 and the very first settlement
of Hulhumalé began in the middle of 2004 with a resident population of just over
1000 people. The current population is approximately 20,000 people.
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The target completion date for the development is 2020 with a target population
of 60,000. At that time the population density would be approximately half the
current density of Malé Island.
Figure 3 Hulhumalé Master Plan (Source: HDC)
Development so far has primarily been residential in the north east corner of
Hulhumalé including social housing. It is understood that some social housing
leases are being sublet to residents from outlying islands thereby frustrating the
aim of tackling growing urban congestion in Malé.
Construction of a bridge between Malé and Hulhumalé would be very beneficial
to the further development of Hulhumalé and to achieving the objective of
fostering balanced land use and a diverse range of developments. Commercial
developers would potentially be more likely to invest if Malé was seen to be more
directly within their catchment of potential customers. Malé residents might also
be more likely to move to Hulhumalé if they could more easily commute to their
current employment on Malé thus achieving the aim of reducing urban congestion.
Figure 4 Beachfront residential developments in Hulhumalé
Figure 5 Streetscape in Hulhumalé
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Hulhumalé clearly has great potential to improve the quality of life for the
population by providing a lower density of urban living in a well planned
development which effectively utilizes the land to maximize environmental and
economic efficiency in terms of living space, productivity and provision of
employment. However, it is currently underutilized and it may require better
connectivity to help it to fully realize that potential.
2.3
Ibrahim Nasir International Airport
Ibrahim Nasir International
Airport (MLE) is the main
international airport in the
Maldives. Despite the upgrading
of Gan and Hanimaadhoo
Airports to international
standards, Ibrahim Nasir
International Airport is likely to
remain the main gateway into
the Maldives for tourists.
Tourism accounts for 28% of
Maldivian GDP and more than 60%
of foreign exchange receipts.
Figure 6 Approach to Runway 36 (Source: Wikimedia Commons © PalawanOz)
The airport completely dominates Hulhulé Island and has been constructed on
reclamation in the lagoon of the island. The airport opened to the public in
April 1966 and has been through a series of renovations and upgrades including
several additional stages of reclamation to expand the land area of the airport.
Figure 6 shows the situation in 2003 before more recent reclamation at the
southern end of the island.
The Maldives Airports Company Ltd. (MACL) was formed in 1994 as a
financially and administratively independent corporate entity to manage the
airport. MACL is governed by a Board of Directors appointed by the President of
the Maldives
On 15 July 2010, the airport was privatised and on 25th November 2010, MACL
officially handed over the aerodrome license of the airport to the newly formed
GMR Malé International Airport Pvt. Ltd, a consortium between GMR Group and
Malaysia Airports. The airport has been leased to the consortium for 25 years with
the aim to develop MLE into a global standard airport by the year 2014. MACL
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will continue to be responsible for some airport functions including Air Traffic
Control and Aviation Security Command.
The centrepiece of the development plans is a new International Passenger
Terminal to be built on a reclaimed lagoon to the east of the runway. Other
developments include extension of the runway to the north to establish a Runway
End Safety Area (RESA) at the south end of the runway.
2.4
Greater Malé
Although the objective of this assignment is to study the feasibility of a bridge
between Malé and Hulhumalé (via Hulhulé), we are aware that this is part of a
larger long term desire to link together a series of islands in the Greater Malé
region.
Figure 7 Greater Malé
As far as the current assignment goes, the main way in which we have considered
this long term goal is in terms of the traffic connectivity. The physical geography
of Greater Malé as well as the current road layout in Hulhulé and Malé lends itself
to the eventual fixed link being a “backbone” running along the perimeter of the
atoll as indicated in Figure 7.
2.5
The Eye of Maldives
One of the islands in the Greater Malé region is Gulhi Falhu which is currently
being developed into the Eye of Maldives.
Global Projects Development Company (Pvt) Ltd has a concession agreement
with the Government of the Republic of Maldives to reclaim and develop Gulhi
Falhu lagoon. Reclamation of Phase I (10 hectares) was completed on 18
September 2010. Phase II (40 hectares) will commence in 2011.
The Eye of Maldives masterplan currently shows a fixed link between Gulhi
Falhu and Villingili islands as indicated in Figure 8.
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Figure 8 Eye of Maldives (Source: Global Projects Development Company Pvt Ltd)
2.6
Funadhoo Island
Funadhoo Island is a fuel storage facility operated by the government and located
between Malé and Hulhulé islands.
It is understood from discussions with the Technical Advisor to the Minister of
Housing and Environment that this facility will be relocated. We have therefore
assumed that it would be possible for the road to pass over this island and indeed
there could be some benefit to linking to this island to facilitate redevelopment
since it is close to Malé.
Figure 9 Funadhoo Island (Source: Google)
The island includes an area of shallow water to the south east where breaking
waves are observed.
2.7
Moon Bay Marina
We are aware of the Moon Bay Marina project from the promotional video which
was widely circulated on the internet in early 2009. If this project were to go
ahead it would have a significant impact on planning of the bridge. However, it is
our understanding that this project will not be progressed and we have therefore
excluded it from our consideration in preparing this report.
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2.8
Site Conditions
2.8.1
Topography
Final Report
The islands are flat and are typically around 1.5m to 2.0m above mean sea level.
2.8.2
Bathymetry
Bathymetric data has been obtained from four sources:
•
Admiralty Chart [1]
•
University of South Florida (USF) bathymetry survey [12]
•
Extract from recent Indian Survey data provided by Maldivian Coast Guard
•
Extracts from bathymetric survey of Hulhulé Island [4]
There are some contradictions in the bathymetric data but it is clear that the water
depth in the channel exceeds 50m and that the reef slopes are generally relatively
steep. The data also appears to consistently indicate that the water is slightly
shallower in the southern part of the channel and that the reef slope of the south
east tip of Malé Island is somewhat gentler.
The USF data is the most detailed and the most recent so we have based our study
on this. For the further development of the project it would be necessary to
validate the USF data and obtain a digitised version.
Shallower
plateau area
Gentler reef
slope
Figure 10 Extract from USF bathymetry data [12]
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2.8.3
Final Report
Metocean conditions
Metocean conditions are expected to be characterised by a moderate tidal range,
strong currents, moderate to rough ocean swells and steady winds. The conditions
are affected by the monsoons. Each year there are two monsoons seasons, the
north-east monsoon, (Iruvai) from December to April and the south west monsoon,
(Hulhangu) from May to October.
Tide
Tidal levels have been determined from the Admiralty Chart [1]. The tidal range
at Malé and nearby is about 0.7m at Spring tides and 0.3m for Neap tides. A mean
sea level of +0.6mCD has been assumed for this current study.
Place
Heights in metres above datum (mCD)
MHHW
MLHW
MHLW
MLLW
0.9
0.8
0.5
0.3
Malé
Current
The Maldives are affected by both seasonal and tidal currents. [1] states that the
Gaadhoo Koa “channel is affected by seasonal monsoons causing strong currents
up to 6 knots across the mouth of the channel.” Tidal currents occur due to the
diurnal filling and emptying of the lagoons through the limited passages in the
barrier reef. The Maldivian Coast Guard informed us that the tidal current strength
in the Gaadhoo Koa has increased due to the reclamations in the area.
Waves
The wave height varies seasonally with the monsoons and June to August during
the south west monsoon has the most potential for large swells. During this period
the predominant wave direction is from the south. Seas are generally moderate
(around 2m wave height) but can be rough (2.5m to 4m wave height) at times.
During the site visit strong breaking waves were observed on the shorelines
exposed to the ocean, specifically the east coast of Malé and the southern
breakwater of Hulhulé Island where minor overtopping was also observed. It was
noted that the wave strength tended to reduce inside the atoll but surf was also
observed at Funadhoo Island despite being some way from the edge of the atoll.
Wind
Steady winds exist at the site with the average monthly wind speed being between
4m/s and 6m/s and with calms never exceeding more than 2% of a month. The
prevailing winds which can become quite strong, are from the SW-W-WN during
the south-west monsoon and N-NE-E during the north-east monsoon. In May to
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October wind gusts may reach between 35-45 knots. However, the Maldives are
not prone to tropical cyclones as it is outside of the cyclone region.
2.8.4
Ground conditions
Archipelago geology
The Maldives Archipelago comprises two chains of coral reef islands located
above the north-south trending submarine Laccadive-Maldives Ridge. The
basement of this ridge formed millions of years ago as the result of hot-spot
related volcanic activity, with subsequent subsidence and carbonate sedimentation
resulting in a thick overlying limestone sequence. The islands themselves, which
only began to form around 5,500 years ago, are composed of reef-derived
carbonate sediment deposited by waves and currents along the rims of coral reef
atolls, giving rise to sub-circular clusters of islands, each surrounding a lagoon.
The geomorphology of the islands is constantly changing through action of wind
and sea which leads to erosion and deposition of banks, beaches and cays.
Due to their mode of deposition and post-depositional processes, carbonate
deposits, and particularly those associated with coral atolls typically exhibit
highly variable characteristics, including zones of unconsolidated or poorly
consolidated granular deposits, zones of cementation, coral cavities and
dissolution voids.
Local geology
After collapse of a section of the north eastern reef slope of Malé in 2002, a study
was made to characterize the engineering geology environment of the margins of
Malé Island, especially the north-eastern slope where the documented upper slope
failure occurred. The Phase 1 Assessment Report [11] has been made available to
us.
Based on interpretation of a high resolution multi-beam bathymetry survey the
report makes a number of conclusions which are of particular significance to the
bridge feasibility:
•
Several surfaces of rupture (head scarps) are observed corresponding to
collapse along the north eastern section of Malé Island
•
Blocks and debris are observed down slope of the collapses
•
The sea floor between Malé and Hulhulé Islands shows karst like figures
(sinkholes) on the underwater plateau. The sink holes form lineaments which
are parallel to the general orientation of the NE shores of Malé Island.
Expected conditions
It is expected that the sea floor will comprise of carbonate deposits overlain in
places by unconsolidated granular deposits (coral sand). Sink holes are expected
in some locations.
Due to the high tidal currents in the channel it is anticipated that sand deposits
will tend to accumulate in deeper areas such as the sinkholes and will not be
present in shallower areas. This has been anecdotally confirmed during our
discussions with the Maldivian Coast Guard who have made a number of dives to
the sea floor and were able to describe the conditions.
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2.9
Final Report
Key Issues
A number of key issues for the project have been identified:
2.9.1
Project Financing
Navigation
Cost & Practicality
of Construction
Operation &
Maintenance
Deep Water
Traffic Congestion
Weak Ground
Conditions
Employment in
Ferry Sector
Airport Height
Restrictions
Environmental
Impact
Project Financing
There are clearly significant economic benefits that would be obtained from this
project and there is great interest from the Government and stakeholders in seeing
the bridge be built. However, the project would represent a significant capital
expenditure and securing the financing of that initial investment is critical to the
project going ahead.
2.9.2
Cost & Practicality of Construction
Intimately related to project financing is the need to reduce costs to try to limit the
initial capital requirements. This requires the bridge to be designed economically
whilst at the same time achieving the project objectives.
In this particular case an economic design needs to respect the practicality of
construction in the remote location of the Maldives. This means considering the
logistics of importation of materials and planning the extent to which precasting
and prefabrication can benefit the project.
2.9.3
Deep Water
The Gaadhoo Koa channel is up to 60m deep and it is a thousand metres from
shore to shore. Strong currents and ocean swells are present in the channel. This
represents a challenging environment for construction and more data is required to
define the metocean conditions in the channel.
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2.9.4
Final Report
Weak and Uncertain Ground Conditions
There is no ground investigation data available for the site. However, the local
geological conditions indicate the ground is likely to be weak and highly variable
carbonate deposits. Suspected sinkholes have already been identified in some
parts of the sea floor. There will be considerable technical challenges in
developing appropriate foundation solutions and reliable geotechnical data is
required.
A secondary consideration with respect to the weak ground conditions is that a
study will need to be made to ensure that the construction of the bridge does not
adversely affect coastal processes and lead to acceleration of the erosion of the
north eastern corner of Malé Island.
2.9.5
Construction of the bridge adjacent to the airport imposes stringent restrictions on
the height of structure that can be built.
Considering the deep water it would be desirable to have long spans but the height
restrictions places limits on the types of bridges and maximum spans that are
achievable.
The span limitations become particularly significant in the reef slope areas where
it is highly undesirable to locate a foundation. This means that the bridge must
span across the slope areas.
2.9.6
Navigation
The bridge needs to have a relatively low profile due to the airport height
restrictions. This will inevitably prevent large ocean going vessels from passing
under the bridge. Therefore the largest vessels which must be able to continue to
safely use the Gaadhoo Koa after construction of the bridge need to be identified
to determine the navigation requirements. Larger vessels will need to use alternate
passages into the atoll and stakeholder consultation on this issue has been carried
out due to its importance.
2.9.7
The bridge will represent a large capital investment and it must therefore be
operated and maintained to provide a high quality service level throughout a long
service life. In the Maldives there are few, if any, bridges and therefore the
institutions to operate and maintain the bridge do not exist.
Implementation of the project must therefore either include creation and capacity
building of a dedicated institution or else turn over the operation to the private
sector to attract experienced international organisations.
The design of the bridge should also seek to minimise the operation and
maintenance burden.
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2.9.8
Final Report
Traffic Congestion
There is a concern that the construction of the bridge could increase traffic
congestion on the islands. This is an issue that needs to be addressed with a traffic
impact assessment. Ways in which congestion can be tackled could include:
•
Promoting public transport (buses) on the bridge
•
Selecting a landing point which provides good traffic dispersal in Malé
•
Implementing traffic improvements to facilitate dispersal
•
Restricting types of vehicle that are permitted to use the bridge – this could
mean private vehicles registered in specific areas or introducing a taxi zoning
scheme to control numbers of taxis permitted to operate in specific areas
2.9.9
Impact on employment in ferry sector
Although the construction of the bridge will bring economic benefits to the
majority of the population there is a concern that it will cause job losses for those
currently either directly or indirectly employed in ferry operations.
At present, the Malé-Hulhumalé ferry service is operated by the Maldives
Transport and Contracting Company (MTCC), a majority state owned enterprise
which operates a number of ferry routes as well as providing other transport,
logistics and construction services. There are 18 return trips per day and the
journey takes approximately 20 minutes. The service is operated in a relatively
efficient manner and prices appear to be based on cost plus profit. [6]
On the other hand, the Malé-Hulhulé service is provided by a number of
individual operators working as an association or cartelized union as opposed to a
company. The fare charged is relatively expensive compared to MTCC fares but
there appear to be deliberate inefficiencies in the operation due to there being
significantly more ferries operating than are actually required meaning that each
vessel is only utilised for approximately 20% of the day. [6]
It is worth noting that the
reduction in demand for ferries
to Hulhumalé may be offset by
increasing demand for ferry
Bus operations on the bridge provide
operations between Malé and the
an opportunity for reemployment as
Eye of Maldives development
well as promoting public transport
meaning that some ferries could
simply shift the route on which
they operate. However, there
could still be a net reduction in
demand for ferry services and to avoid negative social impacts it is suggested that
the government could implement reemployment schemes for affected persons.
It is possible that bus operations on the bridge could provide appropriate
reemployment and this could be promoted by
•
Retraining schemes (e.g. bus drivers licence, mechanics training etc.)
•
Trade-in scheme whereby the government could provide mini-buses in return
for ferries.
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•
Direct intervention (employment quotas)
•
Toll structure on the bridge which promotes the use of buses
There would be some costs associated with these schemes but these would be a
small percentage in comparison to the overall project cost.
Since October 2010, MTCC has operated the Hulhulé to Hulhumalé bus service
and there is clearly the possibility for their bus operations to expand to
compensate for the loss of the Malé to Hulhumalé ferry service.
A decision will need to be taken on whether bus operations are to be carried out
by a single franchised company or whether registered individuals operating nonscheduled services could also be permitted to operate buses. In Hong Kong, both
systems are run in parallel (Figure 11) for the public light buses and a dual system
could also be considered in the Maldives. This could provide greater opportunity
for individual Malé-Hulhulé ferry operators to participate in the bus sector.
Figure 11 In Hong Kong, green minibuses operate a scheduled service, with fixed routes
and fixed fares whereas red minibuses run a non-scheduled service according to market
demand, although many routes may in effect become fixed over time.
2.9.10
Environmental impact
The bridge will be constructed over coral in a marine environment which means a
careful assessment of the potential environmental impacts will be required and an
environmental management plan will need to be developed.
2.10
Key Stakeholders
In developing a project of this nature, stakeholder consultation is important to
ensure that views of interested parties are taken into account. During the course of
this feasibility study a number of key project stakeholders have been identified:
•
•
•
•
•
•
Government of Republic of Maldives
Maldives Airport Company Ltd
GMIAL
Housing Development Corporation
Environmental Protection Agency
Maldives Ports Limited
•
•
•
•
•
•
Maldivian Coast Guard
Maldives Transport and Contracting Co.
Malé to Hulhulé Ferry Operators
STELCO
Maldives Water & Sewage Co.
Residents of Malé and Hulhumalé
Preliminary consultation was carried out with some stakeholders during the site
visit and this report takes account of the views expressed. Further consultation
will need to be carried out during later project stages.
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3
Alignment Options
3.1
Alternatives Considered
Ibrahim Nasir International Airport stands between Hulhumalé and Malé and any
road linking the two must pass either to the north or to the south of the runway.
Figure 12 Satellite image of Malé and Hulhumalé
The Hulhumalé to Hulhulé Link Road already connects to the southern end of the
runway and it is natural to consider extending this across the Gaadhoo Koa
channel to reach Malé, particularly since this road will also provide access to the
new International Passenger Terminal which is currently under development.
Alignment options passing to the north of the runway were briefly considered but
were discounted due to the significant additional cost and environmental impact
which would be associated with such a circuitous route. Therefore, all alignment
options considered pass to the south of the runway.
Three alignment options have been developed which are:
•
Option A – which crosses the channel in a northeast-southwest direction and
connects the southern tip of Hulhulé Island to the shallow water to the
southeast of Malé. The alignment follows a gentle curve in order to stay clear
of the sinkhole features observed further north in the channel and makes
landfall close to the Tsunami Memorial.
•
Option B – which is the most direct route across the channel and has the
shortest shore to shore distance although it crosses the sinkhole area described
in Section 2.8.4. This option is aligned in an east-west direction and the
landing point on Malé is the vacant land to the north of the beaches
•
Option C – which makes use of Funadhoo Island to separate the crossing into
two parts albeit following a somewhat indirect route.
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These alignment options are illustrated in Drawings 217093/001 and 002 which
are provided in Appendix A.
3.2
Landing Points and Traffic Dispersal
3.2.1
Option A
Alignment Option A makes use of the open area to the east of the junction
between Ameene Magu and Marine Drive.
At this location the streets are relatively wide and offer excellent dispersal into the
existing Malé road network. Space is available for construction of the bridge
abutments although it is likely that the helipad may have to be relocated in order
to provide sufficient space for tolling facilities.
This landfall also gives the best opportunity for future connectivity to Villingili,
either via Ameene Magu or along the southern section of Marine Drive.
On Hulhulé Island this option provides excellent connectivity as the road would
be a direct extension of the Hulhumalé to Hulhulé Link Road. A spur to the
airport facilities west of the runway would of course be retained.
Figure 13 Landing Point A on Malé Island
Figure 14 Marine Drive
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Figure 15 General view of landing point (left) and Ameene Magu (right)
3.2.2
Option B
Alignment Option B would make use of the open land to the south of the
STELCO substation on Malé Island which provides sufficient space for the bridge
abutments, connection to the local road network and toll plaza. The ownership of
this land was not established but it is not currently being used.
A
Figure 16 Landing Point B on Malé Island
The main disadvantage with this landing point is that Bodhuthakurufaanu Magu is
quite narrow at this location meaning traffic dispersal would be difficult.
Figure 17 Bodhuthakurufaanu Magu
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Figure 18 Narrow one-way side street (location A in Figure 16)
On Hulhulé Island the traffic connection is the same as Option A.
3.2.3
Option C
The purpose of Option C is to make use of Funadhoo island and to split the
crossing into two smaller stretches.
The landing point on Malé would be at or near Fisherman’s Park on the north side
of the island.
Limited land is available at this location and it is likely that reclamation of some
of the harbour area would be required if toll facilities were to be located on Malé
Island. Alternatively the toll facilities could be at the Hulhulé end of the bridge
although this would still require some reclamation.
The landing point is located close to the commercial centre of Malé and
Bodhuthakurufaanu Magu is narrow at this location. Traffic dispersal would be
difficult and would probably require road improvements and one-way systems.
Figure 19 Landing Point C on Malé Island
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Figure 20 Commercial buildings at Landing Point C
Although access is provided to Funadhoo the primary purpose of the link is for
travel between Malé and Hulhumalé and the overall travel time will be increased
by the indirect route.
3.3
Initial Sifting of Alignment Options
3.3.1
Floating Bridge Option
Two fundamentally different types of bridges will be considered in this report:
•
Traditional fixed bridge with foundations on the sea floor
•
Floating bridge
The feasibility of a floating bridge is very dependent upon the wave and current
conditions. At the southern end of the Gaadhoo Koa channel rough wave
conditions are expected which will exceed design values of previously constructed
floating bridges. Even if a design solution could be arrived at it would lead to a
relatively high risk solution which is not preferred. Therefore the floating bridge
is only considered on Alignment Option C which is set back from the edge of the
atoll and where the wave strengths will be significantly lower. There is also
expect to be a reduction in current strength at this location.
3.3.2
Exclusion of Alignment Option B
It is possible to exclude Alignment Option B from further consideration at this
early stage due to the unsuitable ground conditions. The alignment crosses an area
of extensive karst features (sinkholes) which would make selection of suitable
locations for the bridge foundations difficult if not impossible. Furthermore, the
west abutment of the bridge would be located on the steep margin of Malé Island
which is vulnerable to slope collapse.
Alignment Option A crosses the channel further to the south away from the
observed areas of sinkholes and the landfall on Malé Island is the south eastern
point where slope failures have not been observed. The engineering feasibility of
bridge construction on this alignment is much more favourable.
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In terms of traffic, alignment Option Ais also more favourable than Option B
since it can connect directly to wide southern section of Marine Drive providing
dispersal through Majeedi Magu or Ameene Magu. This option will also facilitate
future connectivity to Villingili Island.
The disadvantage of Option A is that it will have a significant impact on the wave
formation at Surfers Beach which is likely to be detrimental to the quality of
surfing. This impact is partly mitigated by the bridge giving easier access to the
beaches on Hulhumalé.
Despite this undesirable impact on leisure resources, Option A must be considered
preferable to Option B since the latter is unlikely to be feasible as explained above.
Option B is therefore excluded from further consideration.
3.3.3
Fixed Bridge on Alignment Option C
If it were highly desirable to include a link to Funadhoo as part of this study then
the construction of a fixed bridge on Alignment C could be achievable. However,
we have not considered this option because:
•
The overall length of the bridge would be greater on Alignment C (and the
water depth is greater) so the cost would be higher
•
The travel time would be greater between Malé and Hulhumalé thus the
effectiveness of the bridge in achieving its primary function would be reduced
•
Traffic dispersal on Malé is less favourable for Alignment C
•
The reef geology is less stable at the Alignment C landing point
For these reasons, we have only considered a floating bridge on Alignment C.
3.3.4
Summary of Initial Sifting Exercise
The initial sifting exercise is summarised in the table below which shows which
options are considered further and why:
Bridge Type
Alignment A
Alignment B
Alignment C
Fixed Bridge
Considered further
Unsuitable ground
conditions – high risk
High cost and poor
functionality
Floating Bridge
Wave conditions are too rough – high risk.
Considered further
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4
4.1
The most significant operational issue associated with the airport is the height
restrictions that must apply.
The airspace around airports is to be maintained free from obstacles so as to
permit aircraft operations at the airport to be conducted safely and to prevent the
airport from becoming unusable by the growth of obstacles around the airport.
This is achieved by establishing a series of Obstacle Limitation Surfaces (OLS)
that define the limits to which objects may project into the airspace.
As a bridge would be located on the south west side of the airport island, we have
established the OLS for Runway 36 (south part of the runway) and have defined
the height limits for objects in this area.
Over the next years the airport will undergo major modifications with the
objective to improve safety and security standards at the airport. From the Malé
International Airport Draft Master Plan [1] we have gathered the following details
regarding the implications for Runway 36:
•
Provision of a minimum 90 metre Runway End Safety Area (RESA) for
Runway 36;
•
Installation of a blast fence, with frangible mounting to protect vehicles on the
perimeter road.
The Draft Master Plan states that the blast fence will be of 3.8 metres height and
60 metres length and will provide protection for vehicles, including catering
trucks, from take-off thrust jet blast from four-engine aircraft such as the B747400. A more recent CAD plan obtained from the Client shows the blast fence now
extended to 220m length but it is assumed the height is not significantly changed.
We have established the OLS based on International Civil Aviation Organization
(ICAO) standards and have used the following assumptions:
•
Runway Code Number 4, Instrument Runway
•
Take-off climb surface of Runway 36 located 190 m north of blast fence
•
Location of threshold 36 will remain unchanged
•
No clearway provided at Runway 36
We have set up the OLS based on these assumptions and have identified the
following surfaces as critical for the elevation of infrastructure, like the bridge,
road connections or other installations in the south or south west of Runway 36:
a) Inner Horizontal: 45m height
b) Transitional: 14.3% slope
c) Take-Off Climb: 2.0% slope
d) Approach: 2.0% slope
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The established OLS can be seen in Figure 21 below. Each contour shows an
elevation increase of 5 metres. The height of the lowest contour equals the height
of the relevant OLS reference point (“0”) which is the runway elevation. This has
been taken as 2m above mean sea level.
b)
b)
a)
d)
c)
d)
Figure 21 Critical OLS (Source: Arup)
These surfaces have been plotted on Drawings 217093/001 and 002 and have been
used in the development of the bridge options. It is important to note that these
OLS were established by Arup for the purpose of this study. In case more detailed
studies are carried out, the OLS and runway elevation should be confirmed by the
airport authorities.
The modifications to the runway ends address two major safety issues, the
introduction of a RESA and the installation of a blast fence. With lengthening the
runway by 140 metres to the north to maintain the Take-Off Run Available
(TORA), the Take-Off Climb surface for Runway 36 is moved north which
provides sufficient height for installing a 3.8 metre blast fence. The road south of
the blast fence must be restricted to vehicles of less than approximately four
metres height.
We have observed that vehicles operating on the road to the west of the runway
result in a transient obstacle in the Transitional OLS and this is understood to be
an acceptable minor non-compliance. However, for the purpose of establishing the
alignment of the bridge we have aimed for a minimum clearance of 4.0 metres
between the road level and both the Take-Off Climb and the Approach OLS. This
will allow vehicles to operate on the road without becoming an obstacle. These
surfaces are considered more critical to aircraft safety than the Transitional OLS.
4.2
Ground Transportation
The construction of a bridge will change the quantity and quality of traffic
between the Malé and Hulhulé islands.
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The largest segment of passengers at MLE are international tourists of which
approximately 45% transfer to domestic air services. The majority of the
remainder transfer to resort hotels by speedboat. Only a limited number of tourists
visit Malé Island.
At present both the resort speedboats and the Malé-Hulhulé ferry services operate
from the harbour area to the west of Hulhulé Island. However, with construction
of the new International Passenger Terminal to the east of the runway the resort
speedboats will operate from within the seaplane lagoon meaning that the western
harbour area will be solely for the ferry services and airport operations.
Resort boat
facilities
Cargo quay
Marine rescue and
firefighting
Male Island
ferry
Figure 22 Harbour facilities after construction of new International Passenger Terminal
Currently, the speedboat and ferry terminals are the main interchange station
between air and ground level transport. With construction of the bridge there
would be continued demand for harbour areas to facilitate transfer to the resort
speedboats but there will also be demand for an interchange station next to the
passenger terminal which connects various road traffic transportation modes. The
interchange station could host pick up, drop off and short term parking facilities
for the following modes of transportation:
•
•
•
•
taxi
limousines
hotel and tour operator buses
scheduled buses
The current airport masterplan allows for the case where the bridge is constructed
by providing a surface parking area to the north of the passenger terminal building
to cater for anticipated demand. It is possible that this could eventually be further
developed into an interchange station with the loss of area for at grade parking
being compensated with the construction of a multi story car park.
After construction of the bridge the cargo quay and Malé Island ferry may no
longer be required. However, there will be a need for road cargo unloading and
bus depot facilities. It is possible that these could be located in the areas vacated
by the sea based ferry and cargo operations.
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4.3
Final Report
Traffic Volume
We are not aware of any studies that have been carried out that estimate the future
sea and road traffic volume.
The road to the south of the airport is currently used for public transportation
between the airport and the development of Hulhumalé and also used as airport
service road between the airport functions to the west and the east of the runway.
The road has sufficient width for 2 lane traffic (approx 7.5m).
The traffic on this road is likely to increase significantly after construction of the
bridge. There will be three components to the traffic:
•
Traffic between Malé and Hulhumalé
•
Traffic between Malé and the main airport facilities to the east of the runway
•
Traffic between the airport facilities to the east and west of the runway
It can be surmised that the most heavily trafficked portion of the Malé to
Hulhumalé road will be the section between the bridge and the International
Passenger Terminal and that any traffic studies to be carried out will need to
consider the airport landside transport infrastructure system as well as the traffic
between Malé and Hulhumalé. It is possible that this section of road should be
widened to a dual two lane carriageway.
4.4
Conflicts Between Road and Air Traffic
The airport improvements plan to solve the conflicts between road and air traffic
at the Runway 36 southern threshold as required by the concession. However, the
road traffic on the Hulhumalé to Hulhulé Link Road in the north east of the future
passenger terminal building is not entirely independent from take-off and landing
activities from the sea plane runways. On a particular zone of the road signage is
currently provided instructing road traffic to give way for sea planes.
As the traffic volume will increase and the type of traffic will change with the
introduction of a bridge, this conflict will become more severe and the current
solution may not be acceptable.
The optimum solution for road traffic would be to relocate the runways but this is
likely to be either very expensive or highly disruptive to airport operations. An
alternative concept could be to close the road during take-offs or landings using
traffic signals and a barrier as is currently adopted at Runway 36 (refer Figure 23).
Since not all sea plane movements cause conflict with the road this solution will
also allow air traffic control authorities to determine when traffic should be
stopped. At present individual drivers use their judgement as to whether the flight
path requires them to give way.
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Figure 23 Signalised traffic control at Runway 36 – this solution could be adopted on the
Hulhumalé-Hulhulé Link Road to deal with conflicts between road traffic and sea planes
Whether this solution is feasible will depend on the future road and sea plane
traffic volume. Also critical will be to develop a reliable technical solution
together with operational procedures that will be accepted by the authorities.
4.5
Airport Emergency Vessels
The airport operates a number of emergency vessels. These are discussed in
Section 5.2.1 with respect to the need to ensure these vessels can navigate under
the bridge.
4.6
Conclusions
The airport height restrictions are very influential to the structural options that can
be considered for the bridge. In view of the deep water, fast currents and ocean
swells that are found in the Gaadhoo Koa, one option that could be considered
would be to construct a bridge from shore to shore without any intermediate
supports in the channel. However, this would require very tall towers which
would violate the height restrictions.
Super long span structures
Stonecutters Bridge, with a span of 1,018m
could cross the Gaadhoo Koa channel
without any foundations in the water.
However the tower is 300m tall making this
kind of long span bridge completely
unsuitable for construction adjacent to the
airport runway.
In addition to these restrictions it is apparent that the construction of the bridge
will have an influence on the airport landside transport infrastructure system. This
has already been considered within the airport masterplan which considers the
scenario of the case of the bridge being constructed. However, as the planning of
the bridge progresses there may need to be further coordination between the
airport development and the government plans for public transport and road
infrastructure between Malé and Hulhumalé.
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5
Navigation Issues
5.1
Marine Activity
Final Report
A wide variety of vessels are found in and around the North Malé Atoll including
large ocean going vessels as well as small powerboats, ferries and dhoni’s.
Container ship (MV Seaboxer)
Cruise ship (Nautica)
72’ sailing yacht
140’ motor yacht
Figure 24 Examples of large vessels (airdraft greater than 20m)
50’ motor yacht
Live aboard dive vessel
Luxury tourist dhoni
Maldivian Coast Guard CGS Huravee
Figure 25 Examples of medium sized vessels (airdraft between 5m and 20m)
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Local ferry
Typical speedboat
Fisherman’s dhoni
Maldivian Coast Guard patrol craft
Figure 26 Examples of small vessels (airdraft less than 5m)
The main berthing areas in Malé include facilities for the airport ferry, the
commercial harbour as well as the marina and ferry berth to the south of the island.
There is a commercial anchorage inside the atoll to the north west of Malé Island.
Figure 27 Berthing areas on Malé
In the commercial harbour operated by Maldives Ports Limited, large cargo
vessels are handled at the alongside berth (Magathu Faalan) as well as at
anchorages offshore using barges. Most of the container ships are handled at the
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Final Report
alongside berth. The port handles all types of cargo except dry bulk, liquefied
petroleum and gases. The airport ferry mainly serves passengers travelling to and
from Ibrahim Nasir International Airport.
Figure 28 Passages currently used to enter the atoll
Referring to Figure 28, the Gaadhoo Koa is the passage between the reefs fringing
Malé and Hulhulé which is about 740 m wide at its outer end and has a depth of
35m in the fairway. At its inner end the passage divides, passing each side of
Funadhoo with deep water in both channels. The Gaadhoo Koa is the
recommended approach to the anchorage area north of Malé for all vessels at safe
speed.
The northern entrance to the atoll is through Bodukalhi (Kanduoiygiri Passage).
Malé Villingili passage is another safe passage for safe entrance to Malé
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anchorage. but “mariners should exercise caution when using this channel as a
shoal of 5.0m lies in the centre of the channel.” [9]
5.2
Airdraft
5.2.1
Airport emergency vessels
As shown in Figure 22, the airport has a dock for marine rescue / firefighting
vessels. These would need to be rapidly deployed in the event of any incident
which involved an aircraft either overrunning or landing short of the runway. It is
critical that the bridge provides sufficient airdraft for these vessels.
The firefighting vessel has an airdraft of approximately 7m and this is the
minimum requirement for the bridge. This requires that the minimum soffit level
of the bridge shall be:
5.2.2
MHHW
+0.9mCD
Vessel Height
7.0m
Safety Margin
1.5m
Minimum Soffit Level
9.4mCD
Controlling factors
A number of controlling factors limit the airdraft that will be available under the
bridge:
•
•
•
•
Airport height restrictions
Maximum gradient of road
Minimum structural depth
Safety margin
These factors are illustrated diagrammatically below:
Figure 29 Limiting factors controlling airdraft
•
The approach surface to the airport runway means the road has to be at a
relatively low elevation on the shore of Hulhulé Island.
•
The road can climb towards the centre of the channel but the gradient has a
maximum value which limits the elevation of the road at the navigation
channel.
•
The bridge itself has a structural depth which has a minimum value which
means that the underside of the bridge is at a lower elevation than the road.
•
Finally, it is normal to establish a safety margin to allow for pitch and heave
of the vessel as well as human error.
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In combination these factors mean that the maximum vessel airdraft that can be
provided under the bridge is approximately eight to twelve metres.
This means that after construction of the bridge large vessels would not be able to
navigate through the channel but smaller vessels including the airport firefighting
vessel would be able to including the airport emergency vessels.
5.2.3
Impact of limited airdraft
Construction of a bridge across the Gaadhoo Koa will inevitably restrict the
shipping that is able to use the channel. However, both Maldives Ports Ltd and the
Maldivian Coast Guard were consulted on this issue and neither stakeholder
raised any concern over the airdraft being limited to around 8m. It was noted that
there are several alternative channels into the atoll and that in the future it is
intended to shift the commercial harbour to Gulhi Falhu in any case.
Therefore, the impact of limiting the airdraft through the Gaadhoo Koa is that
alternative channels must be used for large vessels to enter the atoll. This is likely
to require:
•
Additional navigation marking to be provided on alternate channels
•
Revision of recommended navigation procedures
•
Possible revision of pilot boarding stations
•
Revision of maritime charts to show airdraft restriction
5.2.4
Floating Bridge
For the floating bridge option it is important for the stability of the structure to
keep the bridge relatively low. If the centre of gravity is too high then the
pontoons will become unstable and could invert.
In general, the soffit clearance above water is maintained at 5.0m in permanent
load conditions which will allow safe passage of vessels up to around four metres
in height. This means that only very small vessels can pass such as the resort
speedboats and local ferries.
Because of the need to provide passage for the airport emergency vessels, one
span of the bridge will be provided with a soffit clearance 8.5m above water. This
may require the pontoons to be increased in size for this particular span.
5.3
Span and Marine Safety
5.3.1
Ship Domain Theory
Whilst the available airdraft beneath the bridge represents a physical constraint to
the size of vessel which can pass under the bridge, the span is related to marine
safety. If the span is too little then vessels will be confined to a narrow channel
and are more likely to have to carry out evasive manoeuvres in the vicinity of the
bridge. This in turn leads to a greater risk of ship to ship collision compared to
unrestricted waters.
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One way of assessing the required span is based on ship domain theory [8]. This is
the observation that ships navigate within a “safety bubble” known as a domain
and that when fixed objects or other ships impinge on this domain the ship may
carry out evasive actions.
One Way Traffic
Two Way Traffic
Figure 30 Ship domain theory
5.3.2
Traditional Bridge Options on Alignment A
Due to the deep water in the Gaadhoo Koa, the minimum span which is under
consideration is approximately 200m. At the same time, the airdraft limits means
that only small vessels can pass under the bridge.
A span of 200m means that ships with a length less than or equal to around 20m
to 25m can safely pass each other under the bridge at free navigation speeds. This
will encompass the vast majority of traffic under the bridge including ferries and
speedboats.
Ships up to around 110m length can safely pass under the bridge although the
ship’s captain would consider the span to be restricted waters and is likely to
travel at reduced speed and pass through the centre of the channel and timing the
passage to avoid ship to ship encounters under the bridge.
The traditional bridge options on Alignment A will cut squarely across the straight
navigation channel in open water where there is good visibility and few vessels
will be making manoeuvres or crossing the channel. The marine risk associated
with this option given the long span of the structure is very low.
5.3.3
Floating Bridge Option on Alignment C
For the floating bridge option the span will be approximately 100m. However, for
this option the airdraft is also generally significantly lower meaning that only the
smallest vessels (resort speedboats and local ferries) will be able to pass. Based on
ship domain theory the span will be sufficient for these vessels.
However, the bridge is close to the entrance of harbour areas on both Malé and
Hulhulé Island where vessels may be manoeuvring in different directions.
Furthermore, the pontoons of the floating bridge will be relatively restrictive to
visibility and it will not always be obvious which span a particular vessel intends
to pass under. Some vessels may wish to pass obliquely under the bridge.
For these reasons there is a slightly higher degree of marine risk associated with
the floating bridge option on Alignment C.
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5.4
Final Report
Ship Impact
Bridges in navigable waters must be designed considering the possibility of ship
impact. This means considering the scenarios under which a vessel could become
aberrant within the vicinity of the bridge (whether due to mechanical failure or
human error) and could then go on to collide with the bridge.
The forces due to ship impact from large vessels are very significant and can be
disastrous. However, as has been discussed above, the large vessels will no longer
be able to use the Gaadhoo Koa after construction of the bridge so they should not
be navigating in the vicinity of the bridge.
Medium and small vessels may still navigate under or near the bridge and a
marine risk assessment needs to be carried out to determine the probability of
different sizes of vessels impacting the bridge, the likely impact speeds and
therefore the ship impact forces that the bridge must be designed for. Possible ship
impact scenarios include:
•
Vessel becomes aberrant and collides with the piers of the bridge (hull impact)
•
Oversized vessel attempts to navigate under the bridge and collides with the
deck (mast / deckhouse impact)
•
Ship at anchorage breaks free of its moorings during a storm and drifts
towards the bridge colliding with either pier or deck
The objective of the marine risk assessment will be to determine the necessary
navigation installations and procedure to maintain safety as well as to define the
ship impact forces which the bridge must be designed for.
5.5
Conclusions
The Maldives is an archipelago and marine traffic is an important aspect of
everyday life in the islands. Construction of a bridge across the Gaadhoo Koa will
have a significant influence on how vessels navigate around Malé, especially the
larger commercial vessels. However, due to the large number of entries into the
atoll it has been confirmed by key stakeholders that there will be no adverse
impact to marine operations if appropriate additional navigation aids are provided
for shipping using alternate channels.
All bridge options will provide sufficient airdraft for resort speedboats, local
ferries and the airport firefighting vessel to pass under the bridge and some
options will provide greater airdraft to allow slightly larger vessels to pass.
The span of all bridge options is considered sufficient for safe navigation but the
location of the floating bridge on Alignment Option C is slightly less favourable
than Alignment Option A and may cause some navigation conflicts.
For all bridge options, a marine risk assessment will be required to determine the
necessary navigation installations and procedure to maintain safety as well as to
define the ship impact forces which the bridge must be designed for. Since large
ocean going vessels will not pass under the bridge the ship impact forces are
likely to be manageable. However, the possibility of a large vessel breaking free
of its anchorage and drifting into the bridge does need to be considered.
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6
6.1
Introduction
The purpose of this section is to provide a preliminary environmental assessment
of the proposed bridge options with respect to ecology, water quality, air quality
and noise. Relevant environmental legislations, guidelines and environmental
baseline information are collated. Key environmental impacts during the
construction and operation of the proposed road and bridge link are identified.
Design approaches to avoid and minimize potential environmental impacts,
mitigation measures to address the potential impacts and further investigations are
recommended, where applicable.
It should be noted that this section only presents a preliminary assessment and
detailed studies and/or assessments need to be carried out during later design
stages.
6.2
Environmental Legislation, Guidelines, Policies
and International Conventions
6.2.1
Relevant Environmental Legislation and Guidelines
Environmental Protection and Preservation Act of Maldives
The Articles of the Environmental Protection and Preservation Act (Act No.
4/1993) addresses the following aspects of environmental management:
•
Guidelines and advice on environmental protection shall be provided by the
concerned government authorities;
•
Formulating policies, rules and regulations for protection and conservation of
the environment in areas that do not already have a designated government
authority already carrying out such functions shall be carried out by the
Ministry of Environment, Energy and Water (MEEW);
•
Identifying and registering protected areas and natural reserves and drawing
up of rules and regulations for their protection and preservation;
•
An Environmental Impact Assessment shall be submitted to MEEW before
implementing any developing project that may have a potential impact on the
environment;
•
Projects that have any undesirable impact on the environment shall be
terminated without compensation;
•
Disposal of waste, oil, poisonous substances and other harmful substances
within the territory of the Republic of Maldives is prohibited. Waste shall be
disposed of only in the areas designated for the purpose by the government;
•
Hazardous / Toxic or Nuclear Wastes shall not be disposed anywhere within
the territory of the country. Permission should be obtained for any transboundary movement of such wastes through the territory of Maldives;
•
The Penalty for Breaking the Law and Damaging the Environment shall be
specified;
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•
Final Report
The government of the Maldives reserves the right to claim compensation for
all damages that are caused by activities that are detrimental to the
environment.
Environmental Impact Assessment Regulation 2007
The MEEW issued the EIA Regulation in May 2007 which guides the undertaking
of the Environmental Impact Assessment/Initial Environmental Examination
(EIA/IEE) process in the Maldives. The EIA Regulation provides a
comprehensive outline of the EIA/IEE process beginning from the application to
the details of the contents, the minimum requirements, roles and responsibilities
of the consultants and proponents, the format of the EIA/IEE report etc.
Ban on Coral Mining
Coral mining from the house reef and the atoll rim has been banned through a
directive from the President’s Office dated 26th September 1990. Coral is
prohibited to be mined at any stage of the project.
Guidelines for Domestic Wastewater Disposal
Developed by the Maldives Water and Sanitation Authority and implemented by
the Environment Protection Agency, this guideline serves to improve public heath
by regulating the disposal of domestic wastewater and therefore providing a
cleaner and safer environment through improved sanitation. When handling
wastewater from construction workforce these guidelines should be considered.
Ambient Air / Noise and Water Quality Standards
The Republic of Maldives lacks the necessary environmental standards for the
measurement of ambient air, noise and water quality. Therefore, standards of the
World Health Organization (WHO), those of international recognition, or
standards of developed countries should be used.
6.2.2
Relevant Policies
National Energy Policy
The National Energy Policy looks at existing and emerging energy issues and
constraints of the country. With a focus on sustainable supply and consumption,
the policy also addresses issues of the environment, renewable energy and energy
efficiency. According to the policy document, 3% of energy is from biomass and
solar and the remainder is from refined petroleum products. Diesel fuel accounts
for 83% of the total energy consumption in the Maldives.
Carbon Neutral by 2020
In March 2009, President Nasheed announced the target to make Maldives carbon
neutral by 2020. Hence, in the implementation of the project, careful attention
needs to be given to ensure energy efficiency and reduce transport related fuel
consumption.
National Adaptation Programme of Action (NAPA)
The adaptation policies and strategies of the Maldives are given in the Maldives
National Adaptation Programme of Action [10]. The first component of the
Maldives Adaptation Framework is climate change-related hazards. These
include sea level rise, precipitation, temperature and extreme events.
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6.2.3
Final Report
International Conventions
Convention on Biological Diversity
The Maldives is a party to the United Nations Convention on Biological
Diversity. The objective of the convention includes the following: “the
conservation of biological diversity, the sustainable use of its components and the
fair and equitable sharing of the benefits arising out of the utilization of genetic
resources, including by appropriate access to genetic resources and by appropriate
transfer of relevant technologies, taking into account all rights over those
resources and to technologies, and by appropriate funding”. The proposed
development mainly falls on highly developed areas which are not recognised for
their ecological value [1]. Therefore, a major loss of biodiversity is considered
unlikely.
Climate Change Convention and Kyoto Protocol
The Maldives is a party to the United Nations Framework Convention on Climate
Change (UNFCCC) and the Kyoto Protocol to the UNFCCC. The objective of the
Convention is to stabilize greenhouse gas concentrations in the atmosphere at a
level that would prevent dangerous anthropogenic interference with the climate
system. The greenhouse gas inventory of the Maldives forms an integral part of
the First National Communication of the Maldives to the UNFCCC. In March
2009, the President of the Maldives has announced the target to make Maldives
carbon neutral by 2020.
Third National Environment Action Plan (NEAP III)
The aim of NEAP III is to protect and preserve the environment of the Maldives
and to sustainably manage its resources for the collective benefit and enjoyment
of present and future generations. The principles outlined in NEAP III include the
following:
•
Environmental protection is the responsibility of every individual;
•
Achieve results – The actions, activities, regulations, supervision, reporting,
incentives, information and advice for environmental management shall be
directed and well co-ordinated to achieve the results the citizens want;
•
Promote and practise sustainable development;
•
Ensure local democracy;
•
Inter-sectoral co-ordination and co-operation;
•
Informed decision making;
•
Precaution first;
•
Continuous learning and improvement;
•
Right to information and participation; and
•
Environmental protection complements development.
NEAP III contains environmental policies and guidelines that should be adhered
to in the implementation of the proposed project activities.
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6.3
Final Report
Baseline Conditions
Baseline information in the vicinity of the project site has been collected through
desktop study. The environmental baseline data includes environmental
conditions (which are described in Section 2.8.3), ecology, water quality, air
quality and noise.
6.3.1
Ecology
Protected Areas
There are no protected areas around the project site. The nearest protected areas
are Kuda Haa Dive Site (1995) and Banana Reef Dive Site (1995) which are about
10-12km away from the proposed project sites as shown in Figure 31.
Nevertheless, the Maldives Victory (refer Section 6.3.5) is located within the
project site approximately 400m, 500m and 600m from alignment options 1, 2 and
3 respectively.
Figure 31 Protected areas around the proposed site
Terrestrial Ecosystem
The Malé and Hulhulé Islands are highly developed. The habitat around the
Project site could be categorized into three types, i.e. developed area, plantations
and lagoons as shown in Figure 32. The developed areas cover all the urbanised
land uses such as airport, buildings, roads and other infrastructures
infrastructures and are of low
ecological significance due to their disturbed nature. The plantations are mainly
established for urban landscape purpose and are of limited ecological importance.
Based on the flora survey conducted during Oct-Nov, 2010, for the Malé
International Airport EIA Study [1], the dominant species in Hulhulé is Coconut
palm (Cocos nucifera) which account for more than 57%. Protected species of
Banyan trees (Ficus benghalensis) were observed in the Island, accounting for
about 4.5% during the survey.
The diversity of fauna in the Maldives is considered limited. Majority resides in
the forests of uninhabited islands with limited human disturbance. Since both
Malé and Hulhulé Islands are highly developed,
developed, fauna resources in the two Islands
are considered of low ecological value. Based on the fauna survey conducted
during Oct-Nov 2010 for the Malé International Airport EIA Study, crow,
mosquitoes, lizards, rats, giant ants, common ants, cockroaches and few common
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bird species were observed in Hulhulé Island. No endangered or rare animal
species were identified in the survey.
Figure 32 Habitat map
Marine Life
Qualitative and quantitative surveys were conducted during Oct-Nov 2010 for the
Malé International Airport EIA Study [1]. The locations of survey sites are shown
in Figure 33 and the results are summarized in paragraphs below.
Figure 33 Marine surveys conducted for MLE Environmental Impact Assessment
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Site 1
Visual inspections were conducted at Site 1. The marine benthos at this site
consist mainly of coral rock and rubble with occasional coral heads (Pocillopora
meandrina, Favia sp., Acropora sp.) attached with some of them entangled in
fishing lines. The most abundant fish species at this site are the Damselfish
Abudefduf vaigiensis and Chrysiptera biocellata, Soldierfish Myripristis sp. and
Sweeper Pempheris venicolensis. Surgeonfish Acanthurus lineatus and A.
nigricauda, Butterflyfish Chaetodon xanthocephalus and C. citrinellus and the
“Monocle Bream” Scolopsis bilineatus, “Moorish Idol” Zanclus cornutus as well
as Squirrelfish Neoniphon samara were also observed.
Site 2
Visual inspections were also conducted at Site 2. Fish species at this site are
restricted to patches of scattered live corals (Acropora sp., Pocillopora
meandrina,and Porites sp.). Thalassoma Hardwicke, T. janseni as well as other
wrasses, Acanthurus triostegus, Stegastes nigricans and other Pomacentridae were
observed. The visibility of Site 2 is lower than that of Site 1 and a small fraction
of beach is entirely polluted by solid wastes (such as foam, Styrofoam, plastic
bottles and metal waste etc.).
Site 3
Quantitative reef benthos and fish surveys were conducted at Site 3. Reef benthos
survey was carried out at 8 and 15 m depth with a 20m transect line parallel to the
reef. The fish census was performed at 8 m depth within a belt transect of three
metres width along the 20m transect line.
Reef Benthos
Depth 8 metres: Live coral cover was about 26.5% coverage ± 7.89% (mean ±
SE) in 8 metres depth at site 3. Acroporidae were the most abundant coral family,
covering 13.3% of the transect, followed by Poritidae with 5.7%. Other coral
species such as Faviidae (Favia, Favites, Pavona) and Merulinidae (Hydnophora)
were less abundant. No bleached, dead or broken corals were found during the
survey.
Depth 15 metres: Live coral cover in 15 metres depth was generally lower than
that in 8 metres depth. Coral family composition (Acroporidae, Pocilloporidae,
Poritidae and other families) was equally distributed in this depth of the site. No
bleached , dead or broken corals were found during the survey.
Fish Census
Fish were generally abundant with at least 7 families within the 20×3m belt
transect lines, including Caesionidae (Caesio xanthonota, C. varilineata),
Acanthuridae (Acanthurus spp.), Pomacenttridae (Chromis viridis, Pomacentrus
spp.), Labridae (Thalassoma spp.), Chaetodontidae (Chaetodon kleinii),
Lutjanidae (Lutjanus kasmira) and Cirrhitidae (Paracirrhites forsteri).
In addition to fish present within the transect, various other families/species were
also observed in close vicinity, such as Zanclidae (Zanclus cornutus), Serranidae
(Pseudanthias squamipinnis) and Serranidae (Cephalopholis argus, Plectropomus
laevis).
Rare and Endangered Species
The Republic of Maldives prohibits the killing, catching or extracting any of the
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following within the Exclusive Economic Zone of the Maldives: Black oral,
Triton Shell (Conchs), Giant Clams, Berried female lobsters and those less than
25cm in total length, marine turtles, Napolean Wrasse, dolphins and whales.
According to the surveys conducted in the November 2010 Malé International
Airport EIA no rare and endangered species were observed in Hulhulé reef.
6.3.2
Water Quality
Baseline marine water quality data was derived from [1]. Water quality is
generally uniform at the sites observed.
Chlorophyll data presented in [1], suggests that concentration/productivity in and
around Malé-Hulhulé area is low with a maximum chlorophyll value of 3 mg/m3.
These values are within the typical range of clear coral dominated waters.
6.3.3
Air Quality
Ambient air quality monitoring was conducted at four locations from October to
November, 2010 for the Malé International Airport EIA [1].
The ambient air quality monitoring data indicated that all parameters were within
the WHO guidelines for ambient air quality. The minimum, maximum and 24hour average from all four monitoring locations were extracted and are presented
against the WHO Guidelines. All results fall well below the guideline limits
except for one sample for NOx taken at the Central Store on Hulhulé Island.
Parameter
Minimum
Maximum
24 hr Ave
WHO Guidelines
PM10, µg/m³
15
32
23.2
50 (24-hour mean)
PM2.5, µg/m³
4.1
9.3
6.4
25 (24-hour mean)
SO₂, µg/m³
4.1
7.7
5.3
20 (24-hour mean)
NOx, µg/m³
4
62
9.8
20 (24-hour mean)
CO, µg/m³
32
142
67.8
-1
Notes:
[1] WHO Guidelines do not provide a 24-hour mean value. 10 µg/m³ for 8-hour average period is provided.
6.3.4
Noise
A baseline condition of the noise environment has been derived from [1]. The
locations for which data is available are in Hulhulé, Malé and Hulhumalé Islands.
Hence, it provides a representative measurement for the study area.
The ambient noise levels are considered as moderate to high when compared to
international standards such as the WHO Guideline Values for Community Noise
in Specific Environments. According to [1] this is due to the close proximity to
the sea, windy conditions, closely packed residential areas and movement of
boats. The WHO guideline for industrial, commercial, shopping and traffic areas
is set at 70dB (LAeq) for daytime hours and suggest a 5-10dB decrease during the
night. Most of the site locations fall within this category and comply with the
recommended LAeq for daytime. However, a few commercial and industrial sites
would exceed the upper limit of 60-65dB during the night (e.g.. City Bakery,
Maldives’ Port Authority, Bank of Maldives and STELCO Power House).
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6.3.5
Final Report
The Maldives Victory
The Maldives Victory is the wreck of a 110m long 35,000 tonne freighter which
ran aground and sank on the western side of Hulhulé Island in 1981. The wreck
lies in approximately 35m of water and is a very popular recreational dive site. In
the three decades since the wreck sank it has attracted a wide variety of marine
life which is now well established.
The wreck is considered an artifact of significant environmental importance and
the construction of the bridge should not be allowed to have any adverse impact
on the ecology of the wreck.
6.3.6
Beaches on Malé
There are two beaches on the eastern end of Malé which are important leisure
facilities for the island. Surfer’s Beach and the Artificial Beach. Construction of a
fixed link would make it easier for Malé residents to access the beaches of
Hulhumalé but nevertheless the construction of the bridge should, if possible,
avoid undesirable impacts that would reduce the quality of these existing leisure
resources.
6.4
Potential Impacts and Mitigation Measures
6.4.1
Ecology
Potential Impacts During Construction Phase
Some physical loss of marine habitat (seabed and water column) would result
from construction works at each location where piers are installed to support the
bridge deck. To provide access for construction equipment and labour, each pier
construction site would include an area of works which could be considered as
temporary marine habitat loss. As Malé and Hulhulé Island are located in a large
coral reef system, direct loss to coral species and associated fauna is anticipated.
According to [1], rare and endangered species are not observed in the Hulhulé
reef.
Other potential ecological impacts may result from water quality deterioration
from the following activities:
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•
Pier site dredging
•
Construction site runoff
•
Wastewater from construction activities
•
Accidental spillage of works site chemicals
As the landing sites on either side of the bridge development are both recognized
as highly developed with low ecological significance, no terrestrial ecological
impact is anticipated.
Mitigation Measures During Construction Phase
In order to minimise ecological impacts within the project site the following
mitigation measures are recommended:
•
Minimization of pier locations during detail design (i.e. longer spans)
•
Transplantation of living coral and/or compensatory mitigation of reef area
loss by creation of artificial reef
•
Deployment of silt screens during dredging activities for pier bases
•
Good site practice including site runoff control on terrestrial areas and
prevention of construction waste, including hazardous waste, entering the sea
Potential Impacts During Operational Phase
After construction of the project, the temporary marine works areas should be
self-restored but the Benthic habitats occupied by the pier footprint would be
permanently lost. Marine habitat loss would be minimal as bridge piers would
only occupy a small proportion of the sea area along the bridge alignment.
Indirect impacts associated with water quality deterioration could result from road
surface runoff which is marginally contaminated by vehicles.
Mitigation Measures During Operational Phase
As a precautionary measure surface road runoff can be controlled by
implementing proper drainage systems with silt traps and oil interceptors.
Maintenance at regular intervals is recommended.
6.4.2
Water Quality
Water sensitive receivers within the vicinity of the project would include: salt
water intakes, lagoons, coral and benthic communities and beaches.
The key water quality concern would be associated with the seabed disturbance
during the construction phase. Dredging activities for bridge piers would
inevitably result in the loss and re-suspension of sediment into the water column
which would add to suspended sediment loads. The extent of the suspended
sediment plume would depend on the rate of release, the working methods
adopted, the particle size of the dredged material, settling velocity, prevailing
currents and hydrodynamic conditions.
Sediment laden plumes may directly affect marine organisms through abrasion
and clogging of fish gills and other organs or possibly result in reducing light
penetration. Depending on sediment quality, dredging operations can give rise to
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concerns about possible release of nutrients or organically rich material which
could result in oxygen depletion.
Other potential water quality impacts may result from:
•
Construction site runoff
•
Wastewater and sewage generated from construction activities and workforce
•
Litter from packaging materials and waste construction materials
In order to minimise water quality impacts, the following mitigation measures
may be recommended. These include but are not limited to:
•
Deployment of silt screens
•
Mechanical grabs designed and maintained to avoid spillage
•
Loading of barges and hoppers controlled to prevent splashing of dredged
material to the surrounding water
•
Excess material cleaned from decks and exposed areas before the vessel is
moved
•
Works not to cause foam, oil, grease, litter or other objection matter to be
present in the water within and adjacent to the works site
In addition to standard good dredging practice, other good site practice to control
construction site runoff, wastewater and sewage discharge from construction
activities and workforce, and litter from packaging materials and waste
construction materials, should be implemented.
Changes in hydraulic friction due to the bridge piers may lead to long-term
impacts on the hydrodynamic and water quality conditions. The key issues
potentially associated with this impact are as follows:
•
Reduction or acceleration of tidal flows resulting in siltation or erosion of
seabed (which may result in scour hole formation)
•
Poorly flushed embayments
•
Accumulation of floating debris
•
Affect on coastal processes potentially leading to acceleration of erosion
•
Adverse affect on the leisure quality of surfing on Surfers Beach
There would be no routine discharge of wastewater or contaminated surface
drainage to sea surface watercourse in the operational phase. However, there
would be road surface runoff that could be marginally contaminated from
vehicles.
In order to assess a potential long term impact on the hydrodynamic and water
quality conditions, tidal flow simulations with and without the project are
recommended. Longer spans and hydrodynamic shaping of the piers could be
required if significant effects were observed.
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As a precautionary measure, proper drainage systems with silt traps and oil
interceptors may be installed. Maintenance at regular intervals is recommended.
6.4.3
Air Quality
Air sensitive receivers within the vicinity of the project could include: domestic
premises, hotels, hostels, hospitals, clinics, nurseries, temporary housing
accommodation, school and educational institutes, offices, factories, shops,
shopping centres, places of public worship, libraries, courts of law, sports
stadiums and performing arts centres.
Most sections of the bridge are situated above marine water and adverse fugitive
dust impact from marine-based construction is considered unlikely. However,
construction located at the two landing sites would generate some fugitive dust
with potential impacts on neighbouring sensitive receivers from various
construction activities, including excavation, backfilling, transportation of
materials, and wind erosion.
In order to reduce the dust emission from the project the following mitigation
measures may be recommended:
•
Dusty material covered by impervious sheeting or sprayed with water
•
The load of dusty materials on a vehicle leaving a construction site should be
covered entirely by impervious sheeting
•
High pressure vehicle washing facilities at exit points
•
Stockpiled dusty material should not extend beyond the pedestrian barriers,
fencing or traffic zones
During the operational phase, additional traffic would be generated with
associated vehicular emissions. The associated air pollutants will be NO2 and
RSP. Although the alignment of the three bridge options are primarily over the sea
creating a buffer zone between the traffic on the bridge and the sensitive receivers
the effects of traffic dispersal through the city streets also needs to be considered.
As the ambient air quality results from [1] indicated that all parameters were
within the WHO guidelines for ambient air quality, significant adverse air quality
impacts from the proposed project are not anticipated. However, it is noted that
promotion of buses on the bridge would reduce the emissions generated by
additional traffic.
Air quality modelling combined with traffic studies is recommended to predict the
impacts from increased road traffic.
6.4.4
Noise
Noise sensitive receivers within the vicinity of the project would include:
residential and institutional uses, hospitals, medical clinics, homes for the aged,
convalescent homes, places of worship, libraries, courts of law, performing arts
centres, auditoria and amphitheatres, parks and hostels.
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Construction activities would involve the use of Powered Mechanical Equipment
(PME) including air compressors, excavators, lorries, mobile cranes, concrete
lorry mixers, pokers, rollers, etc. Construction activities which may affect
neighbouring noise sensitive receivers would include:
•
Operation of barge and dredger,
•
Erecting cofferdam
•
Building pile caps and piers
•
Erecting concrete deck segments of the approach
•
Installing the main bridge and side spans
At present it is not planned to use percussive pile driving due to the detrimental
effects of the vibrations on the integrity of the carbonate deposits. Since this
activity has a significant noise impact its omission is a positive reduction in the
potential impacts.
The following mitigation measures may be recommended:
•
Good site practices to limit noise emissions at the source
•
Use of quiet plant and working methods
•
Use of site hoarding as noise barrier to screen noise at ground level NSRs
•
Use of shrouds / temporary noise barriers to screen noise from relatively static
PMEs
•
Scheduling of construction works outside examination periods if necessary
As noted above, road traffic is likely to increase as a result of the project which
has the potential to affect neighbouring sensitive receivers.
If mitigation measures for road traffic noise are considered necessary the
following could potentially be implemented:
•
Strategic planning of alignment route
•
Use of noise barriers
•
Use of low noise surfacing materials
6.4.5
Summary
A preliminary environmental assessment regarding ecology, water quality, air
quality and noise have been considered for the feasibility of a bridge between
Malé and Hulhumalé. Relevant environmental legislations, guidelines, policies
and environmental baseline information have been reviewed and collated. The
key environmental impacts that may be caused by the construction and operation
of the proposed road and bridge link have been identified and mitigation measures
to address the potential impacts are recommended.
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The desk study indicates that destruction of the coral reef is likely to be the most
significant environmental issue.
The design and construction of the bridge should seek to minimise the impact as
far as practical. However, there will inevitably be some reef loss area and this may
require measures to mitigate or compensate for the impact such as coral relocation
and propagation measures and/or reef restoration/enhancement.
A second issue particular to Alignment Option A is that the bridge could impact
the waves on Surfer’s Beach.
It should be noted that the assessment made within this report is preliminary in
nature and mainly based on a desktop study. Should the project progress an
Environmental Impact Assessment will be necessary and the project impacts will
need to be re-evaluated based on site specific survey results as well as the updated
design. Specific and applicable mitigation measures should be provided for
implementation to minimize the impacts.
6.5
Influence of Climate Change
Climate change is leading to
global sea level rise. The
Maldives are particularly
vulnerable to this effect since the
elevation of the islands is
typically less than two metres
above sea level.
Bridges between the islands could
assist the nation in coping with some
of the effects of sea level rise.
The sea level rise at the
Maldives is approximately
0.5cm per year. In addition, there are seasonal fluctuations of around 20cm per
year.
The vulnerability of the Maldives to sea level rise is largely outside the scope of
the construction of a fixed link between the islands. However, Hulhumalé was
built with a formation level 0.5m higher than Malé in order to provide greater
resilience to sea level rise. The bridge, which will promote the development of
Hulhumalé, will therefore be of some benefit to the climate change resilience of
the nation.
The provision of a fixed link could also assist the nation in coping with some
effects of sea level rise, specifically:
•
Facilitating disaster relief efforts
•
Aiding with population mobility in view of shifting land use patterns
A final point is that the detailing of the bridge landings should consider the future
sea level rise and could perhaps be designed to allow for future dyke protection
schemes.
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7
7.1
Functional Cross Section
A significant influencing factor on the cost of the bridge is its width. Simply
speaking, if the deck width is increased the cost will go up. Therefore the cross
section of the bridge needs to be planned in terms of the functional provision
(number of traffic lanes etc.). This essentially becomes a balance between cost
and performance.
7.1.1
Carriageway
The minimum practical configuration for the bridge would be a single two lane
carriageway with 1.0m wide hard strips which leads to an overall bridge width of
10.3m. One disadvantage of this minimum provision is that in the event of a
vehicle breakdown on the bridge, the available width for traffic is severely
restricted and there could be significant congestion.
Figure 34 Carriageway Option 1 – Minimum provision
A second option is to increase the hard strips to 2.0m wide and designate these as
motorcycle lanes. This increases the traffic capacity of the bridge as well as
provides for greater reliability of service since if a vehicle breaks down and pulls
over to the side of the carriageway there is still space for traffic to pass. The
overall bridge width is slightly increased to 12.3m.
Figure 35 Carriageway Option 2 – with motorcycle lanes
A third and final option which could be considered is a dual two lane carriageway
with central divider. The overall width is significantly increased to 19.6m.
Although this option provides for greater traffic capacity it comes at a significant
cost penalty and it is unlikely that the traffic demand could justify this.
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Figure 36 Carriageway Option 3 – dual carriageway
For the purposes of this study, Option 2 has been assumed.
7.1.2
Utilities
In addition to carrying traffic, the bridge could carry utilities. By taking advantage
of a fixed link to achieve multi-purpose objectives it is possible that the economic
benefits of the project can be enhanced. Utilities which could be provided on the
bridge include:
•
Fresh water
•
Sewerage
•
Power
•
Communications
At present each island has its own desalination plant for fresh water production.
MWSC have indicated that it is operationally expensive to have distributed
facilities and that they would like in the long term to consolidate production for
the Greater Malé area, possibly using a facility in Gulhi Falhu.
A single production facility in Gulhi Falhu would require a fixed link between
Malé and Villingili which is not the subject of this feasibility study but which it is
understood is part of the long term development plan for Greater Malé.
However, in the medium term a water pipe on the bridge could still be of benefit.
The present growth of water consumption in Malé is 15% per year and there is
little space available to expand the facilities on the island. MWSC have a
production facility on Hulhumalé and if it had a piped connection to Malé then
expansion of this facility could meet the growing demand.
Another long term plan of MWSC is to introduce waste water treatment facilities.
At present sewage is discharged approximately 200m offshore through a number
of long sea outfalls. There is no space on Malé for waste water treatment so
MWSC have a desire to pipe waste water to a centralised treatment facility, again
possibly on Gulhi Falhu. There are more practical difficulties associated with
piping sewage over long distances compared to fresh water and the cost-benefit
ratio of providing for possible future installation of a sewerage pipe on the bridge
would need to be carefully looked at.
A high voltage power cable could be provided on the bridge to connect together
the power networks of Malé and Hulhumalé. This has the immediate benefit of
building greater resilience into the system by allowing supply and demand
balancing between the two population centres. In the longer term it would allow
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more flexibility in planning where new or improved facilities are provided when
additional capacity is required.
There is an obvious benefit to having communications on the bridge (fibre-optic
cables etc.).
7.1.3
Dedicated public transport provision
It is possible that the bridge could provide a dedicated public transport corridor.
This could be in the form of a light rail system or guided busway. However, these
options would come at a significant extra cost.
A better option would be to promote the use of buses on the bridge. This can
easily be done through a toll structure which is favourable to buses.
Promoting bus operations would also provide employment opportunities to
replace the workforce currently employed directly or indirectly by airport ferry
operations.
7.1.4
Pedestrians
For Alignment Option A it is assumed that there would be no provision made for
pedestrians on the bridge. The pedestrian usage of the bridge is expected to be
very low considering the distance between points of interest either side of the
bridge and would not justify the cost of the additional structural width required for
footpaths.
For Alignment Option C it is assumed that footpaths would be provided on the
section of the bridge between Malé Island and Funadhoo Island to facilitate access
to any proposed developments on Funadhoo which would be within a comfortable
walking distance. Whether or not footpaths should be provided on the longer
section of the bridge between Funadhoo Island and Hulhulé Island depends upon
future development plans and could be studied at the next stage.
7.2
Structural Options (Alignment Option A)
Based on the specific site conditions we have reviewed the suitability of different
kind of bridge structures. The deep water at the site means that the cost of
foundations will be relatively high and therefore the number of foundations
should be minimised. This leads to the selection of long span structural options.
Sea crossing viaducts
Typically sea crossings in shallow water are
built with constant depth continuous
concrete viaducts with a span in the range of
50m to 75m.
This kind of construction is not suitable here
due to the deep water which increases the
costs of foundations.
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7.2.1
Final Report
Options Selection
The shore to shore distance is approximately one kilometre which could be
crossed in a single span, completely eliminating piers in the water. However, this
would require a bridge with tall towers which would compromise the airport
height restrictions.
Initially three different options were considered for the structural form:
Figure 37 Initial sketches of structural forms
A balanced cantilever beam bridge is a long span concrete box girder which could
cross the channel with spans in the range of 180m to 230m. An extradosed bridge
is a kind of a hybrid between a beam bridge and a cable stayed bridge. The
achievable spans are similar to a beam bridge but the structural depth of the deck
can be significantly reduced. The towers are relatively short and do not present an
obstruction to aircraft.
The third alternative considered is a suspension bridge with a span of around
380m. This structural form can achieve a long span with relatively short towers
and can reduce the number of piers in deep water. However, the superstructure
cost is increased due to the suspension system and substantial anchor blocks are
required to transfer the load from the main cables to the ground.
Further review of the site geology and bathymetry now appears to rule out the
suspension bridge option. The highly variable characteristics of the carbonate
deposits that form the barrier reef are unlikely to be suitable for the high bearing
pressures required for the anchor block. Additional bathymetric data obtained has
also revealed that the anchor block on Hulhulé Island would be located on a steep
slope in deep water which would make the ground conditions even less favourable
as well as making construction very difficult.
Therefore we have developed two fixed link structural options:
•
Balanced cantilever beam bridge
•
Extradosed bridge
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7.2.2
Final Report
General Arrangement
The span arrangement of the bridge is dictated by the desire to keep the
foundations away from sloped areas where it is anticipated that the carbonate
deposits will in general exhibit poorer consolidation and increased likelihood of
cavities. Essentially we wish to span over the sloping parts of the reef and locate
the foundations either on the shallow reef flat or on the deep underwater plateau
that forms the base of the lagoon.
This requires a span of approximately 220m to clear the reef slope on the south
east corner of Malé Island and a span of approximately 140m to clear the steeper
slope on Hulhulé Island. In the channel between the two reef slopes typical spans
of 220m are adopted.
7.2.3
Foundation Construction
Without specific ground investigation data the assumptions made regarding
foundation construction must be considered extremely preliminary.
We have assumed that the foundations will be direct footings bearing on the
carbonate deposits. Unconsolidated granular deposits (coral sand) will be removed
if present by airlifting and the base will be made approximately level by an
underwater grab. Coring and grouting will be carried out to search for and fill in
any dissolution features or cavities beneath the foundation. The formation will
then be further levelled by tremmie concrete placed at the turn of the tide when
currents are weaker. A precast concrete foundation will be sunk into position and
levelled. Finally the precast foundation will be base grouted to provide good
contact to the tremmie concrete formation.
At present we are assuming that a bearing capacity of approximately 200 kPa will
be achievable by such procedures.
7.2.4
Balanced Cantilever Bridge Option
Refer to Drawings 217093/021 and 022 which are provided in Appendix A
The balanced cantilever bridge requires a deep girder at the piers to provide
sufficient strength to resist the vertical loads on the bridge. A typical economic
span to depth ratio is 18:1 with the practical engineering limit being
approximately 20:1.
There are significant constraints to the depth of the girder introduced by the
approach obstacle limitation surface at the airport and this has led to the following
compromise situation at Pier E2:
•
The bridge superstructure will be clear of MHHW but the soffit level is lower
than the optimal level and the superstructure could be subject to wave actions
in rough conditions
•
The span to depth ratio is designed at the engineering limit of 20:1
•
The clearance to the approach OLS has been reduced from the desirable 4.0m
to 2.5m. Although the structure is below the OLS high sided vehicles could
impinge on the edge of the OLS.
•
The vertical gradient of the road exceeds the desirable maximum of 4.0%
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It should be noted that there will be a monolithic connection without bearings at
Pier E2 which makes the situation with respect to wave action slightly better but
nevertheless the above situation is not ideal.
Construction of the balanced cantilever superstructure will be either with in-situ
travelling formwork or precast segments. The superstructure will be longitudinally
prestressed.
Figure 38 Construction with travelling formwork (left) or precast segments (right)
In the shallow water at the western end of the bridge, it is likely to be more
economical to construct a beam and slab deck bridge with shorter spans (around
30m to 40m). This also has a shallow structural depth which is advantageous in
bringing the road level down to the low elevation of the island whilst still keeping
clear of waves.
7.2.5
Extradosed Bridge Option
Refer to Drawings 217093/026 and 027 which are provided in Appendix A
The span arrangement of the extradosed bridge is identical to the balanced
cantilever bridge but the extradosed bridge does not require such a deep girder at
the pier since extra support is provided by the stay cables. This neatly solves all of
the issues at Pier E2.
An extradosed bridge still has a relatively substantial girder and vertical loads are
carried by a combination of beam action in the girder and support from the stay
cables. This allows the towers to be relatively short compared to a cable stayed
bridge which means that the airport height restrictions can be respected.
The stay cables will be multi-strand cables which consist of a number of
individually galvanised and sheathed strands contained within an HPDE tube. A
saddle will be provided in the towers using state of the art technology to achieve
high performance with respect to fretting fatigue.
The tower of the extradosed bridge is visually striking and creates an opportunity
for some aesthetic treatment in order to provide a more attractive structure.
However, the structure should also respect engineering principles and the need for
an economic solution.
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We have developed an elliptical tower form reminiscent of the reefs which are
iconic to the Maldives. A number of alternatives could also be considered to select
the most visually appropriate tower.
Figure 39 The iconic form of Maldivian reefs
7.3
Floating Bridge Option (Alignment C)
Refer to Drawings 217093/31 to 33 which are provided in Appendix A
A floating bridge option has been developed to examine whether this could lead to
a reduction in costs by eliminating the deepwater foundations.
Although floating bridges are not common, there are a number of existing
examples in the world. Modern floating bridges can be divided into two types;
pontoon girders where the bridge deck is a continuous floating box structure and
pontoon foundations where the bridge deck spans between individual floating
pontoon structures. The latter solution has become more prevalent and has the
following advantages:
•
Wave and current forces on the bridge are reduced
•
Small vessels can navigate under the bridge
•
The durability can be improved by keeping the deck clear of the water
We have developed a pontoon foundation solution. Steel truss girders span 100m
between floating concrete pontoons. The pontoons have a recto-circular shape to
reduce hydrodynamic forces and they are sized to ensure the bridge is stable
against overturning.
The pontoons will require mooring cables to hold them in position. Two pontoon
foundation bridges in Norway have been built without mooring cables in water
depths exceeding 300 metres. The deck is curved and develops in-plan arch action
to resist horizontal forces. However this relies on competent rock at the bridge
abutments and the current speed and wave conditions at those bridge sites are not
as severe as in this location. Therefore we have assumed a traditional mooring
cable system.
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Each mooring cable will consist of a number of spiral strands in parallel.
Redundancy will be built in so that the loss of any single strand does not endanger
the structure.
Figure 40 Floating Pontoon Bridges in Norway
The complex bathymetry in the sloping regions of the reef together with the likely
poor ground conditions mean that not all locations are suitable for anchoring
mooring cables. Therefore some pontoons are not moored or are only partially
moored. These pontoons will be held in position by the deck which is itself held in
position by the pontoons which are fully moored.
7.4
The operation & maintenance activities fall into several different categories of
activity:
Type of Activity
Example Activities
Day to day operation of the bridge as a highway
Collection of tolls etc.
Day to day visual inspections and routine
maintenance
Replacement of lamps, cleaning of drainage etc.
Detailed inspections
Annual inspection, principal inspection at six
yearly intervals
Major maintenance that is required at regular
intervals
Resurfacing etc.
Abnormal maintenance
Replacement of bearings, expansion joints etc.
The day to day operation and maintenance of the bridge does not differ
significantly between the different bridges. However, there are some important
differences in the detailed inspection and major / abnormal maintenance activities.
As far as possible, the bridges will be designed and detailed to reduce inspection
and maintenance requirements. For example, bearings will be replaced by
monolithic connections where possible and intermediate expansion joints will be
avoided as much as possible.
The durability design will need to take account of the marine climate and
appropriate specifications will be required for materials and workmanship.
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Supervision of construction activities is also critical to ensuring that the as-built
structure achieves the design intent with respect to quality and durability.
Design Life
The bridges will be designed, detailed and built for a design life of 100 to 120 years. This
represents standard international practice and is longer than the design life of buildings due to
the high capital cost and the critical importance of key infrastructure.
To specify a design life of 120 years does not imply demolition and replacement will be
required after this time but after the end of the design life there will be an increasing risk over
time that major rehabilition works will be required to keep the bridge in service.
Planning for a structure to achieve its design life means that the designer intends that the
structure shall fulfil the design criteria throughout the period not that the structure shall remain
unchanged. Furthermore, it should be recognised that some degree of maintenance and repair
will be required for the structure to achieve its design life.
The balanced cantilever concrete beam bridge represents a very low maintenance
solution. There are few structural components. All elements are concrete which
generally requires less maintenance and all critical elements will be in
compression which will limit cracking. The columns are in compression due to
gravity loads and the deck is in compression due to prestress.
The extradosed bridge will require a slightly greater effort for inspection &
maintenance. This is due to the introduction of stay cables which are high tension
steel components provided with a multi-layer corrosion protection system. The
integrity of the corrosion protection requires regular inspection. Furthermore the
design life of stay cables will be around 50 years meaning that replacement of the
stay cables during the design life of the structure is envisaged and this is a
significant abnormal maintenance operation.
The floating bridge will require significantly more inspection & maintenance
effort. There are two key issues, namely the steel superstructure and the mooring
cables.
A steel superstructure has been introduced to make the bridge lighter and
therefore able keep the size of the pontoons within reasonable limits. The use of
steel in a marine environment requires regular inspection of the paint system and
routine touch up maintenance. Furthermore, a complete replacement of the paint
system will be required at approximately 20 to 25 year intervals representing a
major maintenance operation. The steel deck also has fatigue critical welds which
must be the subject of detailed inspections to ensure there is no fatigue crack
propagation and these welds are in difficult to access areas on the underside of the
bridge.
The mooring cables are high tension steel elements which are permanently
submerged in salt water. The cables are connected to the pontoons below water
level to avoid the highly corrosive splash zone environment but nevertheless
entrained air in the water will lead to corrosion of the cables over time. They will
require detailed inspection by divers at regular intervals to check for wire breaks
and the design life of the cables will be approximately 15 to 20 years meaning that
replacement will be required several times during the design life of the structure
and this is a significant major maintenance operation.
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7.5
Final Report
Appearance of the Bridge Options
An artistic image has been prepared showing how each option would appear from
the roof terrace of the Hulhulé Island Hotel. This viewpoint was selected because
it allows all options to be visualised from a single place and it gives a good idea of
the scale of the bridge with respect to the surrounding landscape.
Further images have been prepared showing each option from a closer viewpoint
set against an artificial background to give a better idea of the actual appearance
of the bridge itself.
The artistic images are provided in Appendix B. Small scale reproductions of the
close viewpoint images are provided below for ease of reference.
Balanced cantilever bridge on Alignment A
Extradosed bridge on Alignment A
Floating bridge on Alignment C
Figure 41 Appearance of the different bridge options
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8
8.1
Methodology
There are generally two different methods available for estimating the
construction cost of infrastructure projects:
•
Top down estimate based on historic construction costs of similar projects
calibrated or adjusted for features unique to the project
•
Bottom up estimate based on detailed quantities of resources required for the
construction and using market rates to evaluate the cost
Within the scope of this feasibility study a top down estimate has been carried out.
For bridges, the cost of construction is normally considered in terms of the rate
per square metre of deck area to allow a pro-rata comparison to be made of
bridges of different lengths or widths but of similar materials and construction
complexity.
There are no historic projects of a similar nature in the Maldives. Therefore
historic construction costs for international projects need to be considered. The
adjustments that need to be made for features unique to this project are:
•
Construction in the Maldives where all materials need to be imported
•
Construction in deep water with weak and uncertain ground
Although material costs are relatively high in the Maldives, labour costs are
relatively low compared to the countries where suitable reference projects have
been identified. This has been taken into account in the cost adjustment.
8.2
Fixed Bridge on Alignment A
The estimated construction cost of a fixed bridge on Alignment Option A at
current prices is USD 70 million to USD 100 million. This is based on a unit rate
of USD 5,250 to 7,500 per square metre for the main bridge and USD 1,750 to
2,500 per metre squared for the approach spans.
There is little difference between the balanced cantilever beam bridge and the
extradosed bridge in terms of cost. The span configuration and foundation details
are the same for both bridges with the only difference being the superstructure.
Although this will have a cost implication, the difference will be relatively small
and the span of 220m is in the range where both superstructure types are likely to
be similar in cost. Therefore we have not differentiated between these two options
in our cost estimates at this stage.
8.3
Floating Bridge on Alignment C
The floating bridge was initially proposed as an option which could reduce costs.
However, after further study it is not clear that this would be a more economical
option. Since this type of bridge is very rare in the world there are few reference
projects that can be used as a basis for cost comparison. The closest example is
the Bergsøysund Bridge in Norway which was built at a cost of USD 6,050 per
square metre in current prices. It can be seen that this is within the range expected
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for the fixed bridge options. It is in fact possible that this bridge could actually be
more expensive than a fixed bridge option because:
•
The total length of the bridge is greater than the fixed bridge options.
•
Although the foundations are not required, large concrete pontoons must still
be constructed and a mooring system with anchorages is still required.
•
The design current speeds and wave heights are more severe than for the
Bergsøysund Bridge
•
The superstructure must be made of steel rather than concrete in order to save
weight. Therefore the cost of the superstructure will be higher than for the
fixed bridge options.
At this stage we believe it would be prudent to assume that the cost of the floating
bridge will be similar to the cost of the fixed bridge option and will be in the
range of USD 70 million to USD 100 million.
Having said this, if the cost proves to be towards the lower end of our range of
expectations and the cost of the fixed bridge proves to be towards the higher end
then the floating bridge could still potentially prove to be an economical solution.
There is simply insufficient data at this time to reliably determine which would be
cheaper.
8.4
Operation & Maintenance Costs
Operation & maintenance costs are generally expressed as a percentage of the
construction cost.
The average annual cost of bridge operation and maintenance in Western Europe,
seen over the lifetime of a bridge, in relation to the construction cost is generally
recognised to be in the range of 1 to 1.5%. For major bridges the recurrent cost is
generally a lower percentage due to economies of scale, durable design, routine
preventative maintenance and regular inspection.
The following annual operation and maintenance costs have been assumed
considering the relative inspection and maintenance complexity:
•
Balanced cantilever beam bridge
0.5%
•
Extradosed bridge
1.0%
•
Floating bridge
1.5%
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9
9.1
Alternatives for Financing the Bridge
Traditionally the provision of highway infrastructure is considered a public sector
service and bridges and the like are financed through grants or funding supplied
by the government.
However, in a growing number of cases private finance is being utilised for
investment in highways and bridges.
The Strategic Action Plan of the government includes five priorities, one of which
is Macroeconomic Reform to support private sector-led economic growth. It
entails reducing the role of the state in the economy. A number of private finance
projects have been initiated including of course the privatisation of Ibrahim Nasir
International Airport and the government is experienced with, and keen to
promote, private finance.
Considering the scale of this project, the capital expenditure requirement even
when spread over several years, would be significant compared to current
government expenditure. This makes the use of private finance particularly
attractive.
Malé-Hulhumalé Bridge
General public services
Defense
Education
Health
Social security and welfare
Housing and community amenities
Agriculture
Industry
Electricity, gas, and water
Transport and communications
Other economic services
Others
Figure 42 Comparison between 2009 central government expenditure [3] and preliminary
expenditure estimates for Male-Hulhumalé bridge spread over four years
9.1.1
Public Private Partnership
A Public Private Partnership would involve a contract between a public sector
authority and a private party, in which the private party builds the bridge and
assumes a degree of financial, technical and operational risk in the project. The
degree of ownership between the public and private sectors would be negotiated
as part of the concession agreement.
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In some types of PPP, the cost of providing the bridge would be borne exclusively
by the users of the bridge and not by the taxpayer. In other types capital
investment is made by the private entity on the strength of a contract with the
government to provide agreed services and the cost of providing the service is
borne wholly or in part by the government.
Government contributions to a PPP may also be in kind (notably the transfer of
existing assets). The government may also provide a capital subsidy in the form of
a one-time grant, or Viability Gap Funding, so as to make the project more
attractive to the private investors. In some other cases, the government may
support the project by providing revenue subsidies, including tax breaks and/or
guaranteed annual revenues for a fixed period. (annuities).
The applicable type of PPP structure is based on the outcomes of detailed
technical and financial studies. If the project is to seek private finance then a
robust preliminary design and PPP structure needs to be developed to assure the
prospective bidders that:
•
The project is technically feasible
•
The project is financially viable
•
The project risks have been identified and are acceptable
At the same time, the preliminary design will define the project requirements to
ensure that the government receives the required service levels and that the bridge
itself is built to the required quality. The PPP structure and principles of bidding
will also be developed to ensure the government achieves value for money.
It should be noted that the private sector will include risk in their cost estimations
and therefore if unreasonable risk is transferred to the private sector the value for
money will decline. An important part of preparing the project for bidding on a
PPP basis is to comprehensively identify project risks, mitigate them where
possible and then to provide an equitable sharing of risk between the government
and the private partner with transfer of risk to the insurance sector as appropriate.
9.1.2
Development Aid
It is possible that the government could seek international aid to assist with
financing the project. The scale of investment required exceeds the typical scale of
multilateral aid to the Maldives. Although there are clear economic benefits to the
bridge a robust case would need to be made to potential donors to demonstrate
that the project should be supported. The key issues that are likely to be of interest
to aid agencies include:
•
Relief of urban congestion in Malé
•
Improving accessibility and mobility of the local population for social and
economic purposes and thereby increasing livelihoods
•
Addressing urbanisation trends from the atolls to the Greater Malé region
•
Climate change resilience
•
Enhanced water security
For a project of this scale it is probable that multilateral agencies such as the
Asian Development Bank or World Bank would be looking for co-finance from
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international governmental development agencies as well as for a portion of the
financing to come from the Government of the Republic of Maldives.
To seek development aid for the project it is suggested that the government should
initially reach out to potential donors to determine if there is any interest. It would
be beneficial that preliminary technical and financial studies have been completed
to provide indicative justification. If there is potential for development aid to be
brought to the project then a detailed feasibility study would need to be carried out
addressing the specific requirements of the donor agency. This is likely to require
detailed economic and financial assessment of the project, environmental and
social impact assessments as well as technical assessment.
The overall procurement time is likely to be significantly longer if development
aid is used to part finance the project due to the increased levels of safeguards
demanded by the aid sector as well as the greater number of interested parties
which will inevitably prolong approval and tender evaluation periods.
9.1.3
Management, Operation & Maintenance Contract
If the construction of the project is financed by the public sector, possibly with the
assistance of development aid, then it is still possible that a private partner could
be introduced to manage the asset under a Management, Operation &
Maintenance (MOM) contract.
Under a typical MOM contract, a private entity is given a seven year concession
to operate and maintain the bridge. Toll revenue would be collected by the MOM
contractor and this would pay for the concession.
The benefit of an MOM contract is that it would attract skilled international
companies to manage the bridge since the skills and experience are unlikely to be
available locally given that the Maldives have no existing major highway assets.
Although routine inspection and maintenance should be carried out by the
concessionaire and paid for under the terms of the MOM contract, abnormal
maintenance may still require additional government subsidy although the MOM
contractor would implement the work.
9.2
Sources of Revenue
Discussion of sources of revenue depends upon whether one is considering
revenue that could form part of a PPP structure for a private partner or
alternatively revenue that the government could access to finance the project.
Assuming that the project was implemented on a PPP basis then revenue to the
private partner could be based on:
•
Direct user fees (tolls) which could comprise:
•
•
•
Actual cash received at toll booths
Guaranteed minimum revenues to insure against low traffic volumes
Shadow tolling whereby the private partner is paid based on actual bridge
usage but the user is not charged (probably not applicable in this case)
•
Payment of pre-agreed amounts independent of usage of the bridge (annuities)
•
Payment in kind
REP-217093-01 | Issue | 8 August 2011
Page 60
Final Report
The following sources of revenue could also be considered although they would
be comparatively small.
•
Leasing of right of way for utilities
•
Advertising
If the project is financed by the government then this is likely to require public
sector borrowing which would have to be repaid over a number of years. This is in
fact similar to payment of annuities to a private partner. In either case, revenue
sources for the repayments include:
•
Direct user fees (tolls)
•
Indirect user fees (fuel taxes, vehicle taxes, excise duties)
•
Specialised taxes based upon non-transportation activities but aimed at
beneficiaries of the project (e.g. land and property value capture)
•
General taxes which are used for broad purposes (e.g. income tax, property tax)
•
Leasing of right of way for utilities
•
Advertising
Tolls and Payment in Kind are sources of revenue that are of particular interest
and which are discussed further below.
9.3
Tolls
A broad estimate has been made of the potential revenue that could be collected
from tolling of the bridge. It must be emphasised that these estimates are
indicative only and not based on detailed technical studies. The estimate has been
based on the following factors:
•
Willingness to pay based on current ferry charges and taking into account the
premium that could be charged considering the greater convenience of the
bridge
•
Review of ferry schedules and load factors on the Malé to Hulhumalé ferry
route
•
Review of daily passenger demand on the Malé to Hulhulé ferry route
•
Review of vehicle ownership in Malé
•
Estimate of the number of person trips across the bridge per day based on a
horizon year of 2020 assuming that Hulhumalé achieves its target population
of 60,000.
•
Consideration that many of the passenger trips will be by bus and that the toll
charge is only one component of the cost of the journey. This means that the
toll must be less than the estimated price that an individual is willing to pay
for the trip
•
Allowance for toll revenue generated by commercial goods vehicles
There are many unknowns in the above estimates and within the scope of this
study a detailed financial forecast is not possible. The resulting estimates are:
•
Estimated 8,000 to 12,000 passenger trips per day across the bridge
REP-217093-01 | Issue | 8 August 2011
Page 61
•
Final Report
Estimated annual toll revenue of USD 2 to 5 million
The uncertainties have led to a very wide range in the estimated toll revenue.
However, despite this, our preliminary analysis allows us to make the following
tentative conclusions:
•
Toll revenue is unlikely to be enough to finance the construction of the bridge
•
Toll revenue may be sufficient to finance the operation and maintenance of the
bridge on a commercially viable basis
Despite the insufficiency of the revenue to finance the construction on its own, it
is still assumed that bridge will be a tolled facility for the following reasons:
•
The revenue will still be beneficial for meeting the recurrent costs associated
with the project.
•
The revenue could be one component of a wider package in the development
of an appropriate PPP structure
•
An appropriate toll structure could be put in place to promote the use of buses
to avoid that the bridge contributes to increased car ownership and congestion
It must be noted that if toll revenue is adopted within a private finance structure
then the private entity will be interested to maximise revenue. This could
represent a conflict of interest compared to the objective to adopt a toll structure
that promotes public transport. This means that the toll fees which the private
partner is allowed to charge must be very clearly set out in the PPP agreement
together with adequate provision for price escalation etc.
Furthermore, robust traffic forecasts must be developed in order to assure the
private partner that the actual toll revenue realised will be sufficient for their part
in the project to be financially viable. This will require a clear understanding of
which party bears the risk of the actual traffic being below expectations.
9.4
Payment in Kind
Considering that the toll revenue
is unlikely to be able to finance
the bridge, an option worthy of
consideration is Payment in Kind.
The bridge will enhance the value of
Hulhumalé and Payment in Kind can
capture that to pay for the project
This means that the government
contributions to the project
would include the transfer of an
existing asset to the
concessionaire. In theory that
could be any asset with sufficient value to recompense the cost of construction of
the bridge but in practice a politically acceptable solution is likely to require that
the value of the asset is either connected to or enhanced by the project.
In this case, the obvious solution is to provide to the concessionaire land leases /
development rights in Hulhumalé. The expectation is that the construction of the
bridge will enhance the development potential of Hulhumalé and therefore
increase the value of the land. This has a neat synergy and would appear to be a
viable proposition.
REP-217093-01 | Issue | 8 August 2011
Page 62
Final Report
This PPP model could not only be a means of financing the bridge, but could also
kick start the next phase of development of Hulhumalé by introducing a private
partner to the project. Specifically, it could be of interest to transfer to the
concessionaire development rights to the first package of the Downtown
Commercial Zone, possibly together with part of the adjacent Bayview
Condominium District. The government could potentially derive returns from this
approach through taxes charged on the rateable value of the developed land.
These could also be used to offset the cost of the bridge.
The development of an appropriate payment in kind PPP model will require legal
and financial analysis as well as urban planning to determine the most suitable
development packages and leasing terms. However, as an order of magnitude
calculation, based on current residential land sale prices in Hulhumalé a five
hectare plot of land theoretically has a value of approximately USD 100 million.
A cautious approach should be adopted to extrapolating land value in this way
since the sale price achieved per square foot for a small parcel is not applicable to
large areas of land. Nevertheless, this would suggest that financing the bridge
either in part or in full based on payment in kind is at least feasible.
9.5
Conclusions
Based on government policy and current procurement trends in the Maldives it is
believed that an appropriate PPP structure is likely to be the best way of financing
the project.
The project is unlikely to be financially viable based solely on direct user fees
(tolls). Therefore alternative financing and revenue strategies are required. It is
likely that a successful strategy will combine the following elements:
•
Private partner builds the bridge and then maintains and operates it for a fixed
concession period (25 to 30 years)
•
Initial government capital contribution in the form of Viability Gap Funding
•
Additional Payment in Kind based on development rights / land leases for
commercial / high value residential property in Hulhumalé
•
Toll revenue collected by the private partner but respecting a pre-agreed toll
structure which promotes public transport on the bridge
It is worth noting that the economic benefits of a project such as this frequently
exceed the financial revenue that can be generated. This is because there are either
long term benefits which are beyond the time frame of a private investor or
because there are benefits which are associated with the project but for which a
direct user charge cannot be applied.
In this case, the quality of life benefits achieved by reducing urban congestion in
Malé and the enhanced climate change resilience by promoting development on
slightly higher ground are both significant benefits for which direct charges to the
beneficiaries cannot easily be applied. Therefore the fact that the project is not
considered financially viable based on direct user fees should not be taken to
mean that the project is not worthwhile.
REP-217093-01 | Issue | 8 August 2011
Page 63
10
Final Report
Comparison of Options
Bridge Option
1 - Balanced Cantilever
2 - Extradosed
3 - Floating Bridge
Alignment Option
Option A
Option A
Option C
Construction Cost
USD 70M – 100M
USD 70M – 100M
USD 70M – 100M
Annual Operation &
Maintenance Cost
USD 0.35 – 0.50M
USD 0.7M – 1.0M
USD 1.0M – 1.5M
Key Design Issues
Technical feasibility is
highly dependent on ground
conditions. Further study is
required to confirm
alignment and foundation
locations.
highly dependent on ground
conditions. Further study is
required to confirm
alignment and foundation
locations.
highly dependent on waves
and currents at the site.
Further study is required to
establish the feasibility.
Appearance
Possible wave action on
superstructure in rough
conditions
Reef stability at Malé
landing point needs to be
considered.
Traffic Dispersal on Malé
Very Good
Very Good
Poor
Future Connection to
Villingili
Direct
Direct
Indirect
Alignment Issues
Vertical gradients exceed
desirable maximum
No special issues
Indirect alignment will
increase travel time but
fringe benefit by connecting
to Funadhoo
High sided vehicles will be
a transient obstacle at the
edge of the approach OLSe
No special issues
No special issues
Navigation Issues
Potential for
mast/deckhouse collision.
No special issues
Bridge location is less
preferable for navigation
Impact on leisure resources
(beaches)
Impact on leisure resources
(beaches)
No special issues
Serviceability in Adverse
Weather
Good
Excellent
Requires Investigation
Durability
Good
Good
Acceptable
Issues
No special issues
Requires greater technical
expertise for inspection &
maintenance
Requires greater technical
expertise for inspection &
maintenance
Mooring cables will require
regular inspection and
replacement
Each solution has advantages and disadvantages. At present it is not possible to
conclusively recommend a preferred solution. Clearly Option 3 has a number of
disadvantages and we would not recommend this option unless it proved to be
cheaper. As noted in Section 10 there is insufficient data available to determine
the relative costs of the different options which makes it difficult to eliminate
Option 3 at this stage.
REP-217093-01 | Issue | 8 August 2011
Page 64
11
Final Report
Conclusions & Recommendations for
Further Study
All parties consulted were in favour of the construction of a fixed
fixed link to connect
Malé and Hulhumalé.
Construction of a bridge is feasible although there exist a number of significant
technical and financial challenges which must be overcome.
This Feasibility Study was envisaged as an initial scoping study and was limited
by the time as well as the information available. In view of the anticipated
benefits of the project it is recommended that a Preliminary Design study is
carried out with the following objectives:
•
Gather additional data
•
Confirm technical details of the project
•
Assess the impacts of the project
•
Update cost estimates
•
Develop procurement model for the project addressing the financial
requirements
Feasibility Study
Feasibility Study
Preliminary Design
Preliminary Design
Detailed Design
Detailed Design &
Construction
Construction
Contract
Bid Process
Management
Project
Preparation for
Aid Agreement
Design and
Build Tender
PPP Tender
Detailed Design
Design and
Build Contract
Concession
Agreement
Construction
Contract
Figure 43 Possible procurement routes
During the Feasibility Study, three bridge options have been developed. At
present it is not possible to recommend one single solution. Therefore part of the
Preliminary Design will be to further evaluate these options in order to more
accurately define their techno-economic characteristics and to build a consensus
as to the preferred option.
After the Preliminary Design, depending upon the procurement model adopted,
the government can either appoint a consultant directly to carry out the detailed
design (traditional Design-Bid-Build procurement) or else the project can be
REP-217093-01 | Issue | 8 August 2011
Page 65
Final Report
further developed under a Design & Build or PPP model. In the latter case, a Bid
Process Management assignment will be required in order to develop the bid
documents for the project including the Employer’s Requirements. In the case of a
PPP model, the bid documents will need to include necessary financial, legal,
traffic forecast, risk management data etc to show that the proposed PPP
arrangement is commercially viable for the prospective tenderer. A final
procurement option using international aid is likely to require an additional stage
of project preparation prior to starting on detailed design.
An approximate timeline for the project for each of the procurement routes is
given below. It is important to note that the overall procurement timeline is very
dependent upon the duration required for decision making and project approvals.
The duration anticipated for Preliminary Design itself is approximately 15 months
which is mainly driven by the need to provide enough time for the offshore
geotechnical investigation to be carried out and the results incorporated into the
design. The 48 months assumed for construction is considered to be a relatively
conservative estimate which could probably be reduced once the site conditions
are more accurately determined.
Figure 44 Indicative procurement timeline
The specific tasks which are envisaged under the Preliminary Design are:
•
Obtain validated and digitised copy of USF bathymetric data or carry out
bathymetry survey of preferred bridge corridor(s)
•
Topographic survey of bridge landing points
•
Hydrological survey (waves and currents)
•
Geotechnical investigation
•
Survey of existing & proposed utilities
REP-217093-01 | Issue | 8 August 2011
Page 66
Final Report
•
Conceptual design of bridge options and selection of preferred option
•
Development of design criteria
•
Marine risk assessment
•
Traffic forecast and traffic impact assessment
•
Environmental impact assessment
•
Assessment of bridge impact on coastal processes
•
Social impact assessment (e.g. ferry operations)
•
Structural durability assessment
•
Preliminary design of bridge
•
Operation & maintenance plan
•
Estimate of quantities of materials
•
Land requirement plan
•
Update of construction cost estimates
•
Economic assessment
•
Development of procurement approach and procurement schedule
•
Financial assessment
If the preferred procurement route has already been identified at the beginning of
Preliminary Design then the depth of detail of the tasks above could be tailored
appropriately.
It would also be possible to slightly reduce the overall procurement timeline for
the Design and Build / PPP procurement route by integrating the scope of works
of the Bid Process Management into the Preliminary Design since this would
allow prequalification to start earlier. The overall procurement time would then be
similar to the traditional design-bid-build route where probably be red
In order to control costs at this early stage of project development it could be
possible to subdivide the Preliminary Design into two stages with the aim to limit
design and investigation costs in Stage 1:
•
Stage 1 - Conceptual Design of options, update of cost estimates and
selection of preferred option
•
Stage 2 – Preliminary Design, assessment of impact, further update of cost
estimates and development of procurement model
However, in order for the conceptual design to be meaningful some physical
investigations and data gathering will be required and an appropriate scope for
this stage could be developed.
REP-217093-01 | Issue | 8 August 2011
Page 67
References
Final Report
[1]
Aecom, Water Solutions, January 2011, Social and Environmental
Impact Assessment, Expansion and Modernisation of Malé
International Airport, GMR Malé International Airport
Private Limited, Maldives
[2]
Admiralty Chart, 2005, Malé Atoll, United Kingdom Hydrographic
Office, Taunton, UK
[3]
Asian Development Bank, Maldives Economic Data,[online] Available
at <http://www.adb.org/Documents/Books/Key_Indicators/2
010/pdf/MLD.pdf> [Accessed 30th June 2011]
[4]
CDE Consulting, 2010, Hulhulé Island Airport Bathy Chart Harbour
Area, Maldives
[5]
GMR Malé International Airport Private Limited, October 2010,
Rehabilitation, Expansion, Modernization, Operation and
Maintenance of Malé International Airport – Draft Master
Plan, Conditions Precedent to Effective Date in compliance
to Clause 6.2.1 Sub-clause (b) (ii) of the Concession
Agreement
[6]
Kumarage, A. S., 2009, A Multi-Modal Public Transport System for
Malé, Maldives, 11th Conference on Competition and
Ownership in Land Passenger Transport, 20-25th September
2009, Delft University of Technology, Netherlands
[7]
Japan International Cooperation Agency (JICA), December 1992, The
Development Study on the Seawall Construction Project for
Malé Island in the Republic of Maldives
[8]
Larsen, O. D., 1993, Ship Collision with Bridges – The Interaction
between Vessel Traffic and Bridge Structures, IABSE
Structural Engineering Documents 4, Zurich, Switzerland
[9]
Maldives Ports Limited, Port Information,[online] Available at
<http://www.port.com.mv/portinfo.aspx> [Accessed 30th
June 2011]
[10]
MoEEW. (2007). National Adaptation Programme of Action (NAPA) Maldives. Ministry of Environment, Energy and Water, Malé,
Maldives
[11]
MFR Géologie-Géotechnique SA, February 2009, Malé Reef Slope
Collapse Engineering Geology Assessment Phase 1, ERC
Environment Research Centre, Malé, Maldives
[12]
Naar et al, 2009 [1], General Bathymetric Map of the Margins of Malé,
Maldives 1:5000, University of South Florida, USA
[13]
Naar et al, 2009 [2], General Map With Classes of Similar Slope Angle
of the Margins of Malé, Maldives 1:5000, University of
South Florida, USA
REP-217093-01 | Issue 1 | 8 August 2011
Appendix A
Drawings
TM
@2007
satellite imagery has been reproduced under licence agreement and remains c Google.
N
North Male
Atoll
Hulhumale Island
(See note 4)
Runway 18
4% )
ope:14.
sl
aoch (
on appr
ssi
eci
4;pr
orRW Y Code Num ber3,
ace f
f
onalSur
i
t
ansi
Tr
Hulhule Island
(Existing airport
layout shown)
ANCHORAGE
3% )
14.
ace (
f
onalsur
i
t
ansi
Tr
Funadhoo
Island
(See note 2)
Hulhumale
to Hulhute
Link Road
3% )
14.
ace (
f
onalsur
i
t
ansi
Tr
Refer drawing
217093/002
for detail
Notes:
1.
Obstacle limitation surfaces
(OLS) for the airport are
measured from runway level
which is taken as +2.6mCD.
2.
Seabed profile shown in plan
is based on Admiralty Chart
no. 3323.
3.
It is assumed that the fuel
storage facility on Funadhoo
Island is to be relocated.
4.
Future developments shown
on Hulhumale Island are
based on HDC masterplan.
50
44
44
28
42
43
41
42
27
Op
t
i
o
nC
A
A
C
47
46
C
43
51
C
A
C
51
A
45
2 2.6
30
47
C
43
43
5.1
C
0
45.
0
40.
0
35.
0
30.
0
25.
0
5.
0
20.
0
0.
0
15.
0
10.
0
0.
0
5.
0
10.
0
15.
0
20.
0
25.
0
30.
0
35.
0
40.
0.7
4.2
15 %
B
A
18.2
A
C
A
nB
o
i
t
Op
75
40
Runway 36
10.0
B
15 %
52
30
B
Villingili
Island
45
5.0
24
Obstacle Limitation
surfaces
(See note 1)
10.0
11
30
34
20
24
35
30
24
16
37
6.4
41
15.0
5.6
15.0
3.2
95
8.4
216
50
224
21.5
35
2
12
5.5
0
1
0.8
8
137
8
4
3
36
30
31
69
34
53
41
40
165
50
25.0
47
35
6.4
30
20
27
61
24
5
10
3
30
Gulhi Falhu
Lagoon
2
0
1.4
22.5
6.8
25.0
Fi
l
enam e :
31
onA
i
Opt
3.6
20.0
A
C
20.0
8/8/2011
42
5.0
J:\217093\Arup\CI
VI
L\217093-001.dgn
43
50
20
0.0
kam -l
ung l
i
e
0.0
43
45
a
Ko
Pri
nted by :
Indian
Ocean
B
40
Male
Island
30
A
20.9
43
oo
dh
aa
28.5
G
46
20
0
45.
2.6
38
5
A
30
154
Consultant
Client
Project
Drawing Title
Drawn
Date
OYK
Ove Arup & Partners
Hong Kong Limited
GADL International Limited
Feasibility Study
For Construction of a Bridge
between Male and Hulhumale
Alignment Option- Overview
Checked
B
OPTION A2 REMOVED
08/11
A
FIRST ISSUE
07/11
Rev
Description
Date
Drawing No.
21/07/2011
Approved
DM
MC
Scale
1:25000 on A3
217093/001
B
Tr
an
si
t
i
on
als
TM
@2007
satellite imagery has been reproduced under licence agreement and remains c Google.
N
Notes:
Funadhoo
Island
1.
Obstacle limitation surfaces
(OLS) for the airport are
measured from runway level
which is taken as +2.6mCD.
2.
Seabed profile shown in plan
is based on USF bathymetry
data.
3.
It is assumed that the fuel
storage facility on Funadhoo
Island is to be relocated.
4.
Future developments shown
on Hulhumale Island are
based on HDC masterplan.
Male
Island
Op
t
i
on
C
(optional)
FP
(optional)
FP
(optional)
FP
F
P
(op
t
o
i
n
a
l)
P
F
45.
0
40.
0
35.
0
30.
0
25.
0
20.
0
15.
0
10.
0
5.
0
0.
0
l)
a
n
o
pti
(o
(optional)
FP
P
F
l)
a
on
i
t
p
(o
FP
)
al
on
ti
op
(
Obstacle Limitation
Surface
(See note 1)
F
P
(o
p
t
o
i
n
)
al
FP
(o
pt
i
on
al)
oo
dh
aa
(optional)
FP
(optional)
FP
(optional)
0
.
0
15
%
(optional)
0
.
0
15
%
J:\217093\Arup\CI
VI
L\217093-002.dgn
5
.
0
5
.
0
Surfers
Beach
Fi
l
enam e :
Opt
i
onA
1
0
.
0
Tsunami Memorial
1
0
.
0
8/8/2011
FP
kam -l
ung l
i
e
FP
a
Ko
Runway 36
Artificial
Beach
Pri
nted by :
0.
0
5.
0
10
.
0
15
.
0
20
.
0
25
.
0
30
.
0
35
.
0
40
.
0
45
.
0
G
Opt
i
on
B
Consultant
Client
Project
Drawing Title
Drawn
Date
OYK
Ove Arup & Partners
Hong Kong Limited
Feasibility Study
Checked
Alignment Option A,B and C
B
OPTION A2 REMOVED
08/11
A
FIRST ISSUE
07/11
Rev
Description
Date
Drawing No.
21/07/2011
Approved
DM
-
Scale
1:7000
on A3
217093/002
B
1
1
34
N
8.
4
Plan
by roundabout
= 887m sq.
24
(Alignment option A)
1:4000
Main Bridge
220m
E1
E2
220m
140m
33m
Airport Height
2.5m min.
Restriction Envelope
headroom
Navigation Channel
Notes:
1. All dimensions are in
metres unless otherwise
specified.
11m
11m
CH .
343.
0
W1
220m
4.
4m
W2
140m
Approach
CH .
1283.
0
Approach
CH .
79.
0
Area occupied
CH .
1316.
0
.
343.
0
CH
CH
6.
8
33m 33m 33m 33m 33m 33m 33m 33m
1
+
49
5
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pt
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rde
Bri
tof rBox
ayou i
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ntl
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ner ed Ca
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anc
2
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Ba
(
2 of
eet
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on 1
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rder)
ofBr
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ayout verBox
ralL
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G ene
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Hulhumale
1
3
5
35
on
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GeneralLa
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everBox Gi
l
i
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(
2
Sheet2 of
= 887m sq.
2
600
0+
by roundabout
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1
6
GeneralLa
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everBox Gi
rder)
Sheet2 of
2
0+
400
Area occupied
6.
4
40
30
000
+
1
0+
200
3.
2
24
1
8.
2
At
Gr
a
d
e
1
+
40
0
Ap
p
r
o
a
c
h
0
.
1283
CH .
.
79
.
0
5.
6
200
+
1
0+
000
Male
CH .
1316.
0
h
c
a
o
r
p
Ap
At
Gr
a
d
e
2. All elevations are in
metres above chart
datum.
+1.2 M.H.H.W.
(170m x 12m)
Spread Foundation
Approximate Seabed Profile
based on USF bathymetry data
Elevation
K 13.000
L 67.340m
-100
0+000
0+250
0+500
0+750
1+000
G=2
.
8
2
0
%
G= 0.000%
PVI1+385.
624
El
ev 2.
600
PVI1+255.
099
El
ev 6.
281
K 25.000
L 100.000m
Pi
er1+143.
00
14.
75
K 25.000
L 200.000m
Pi
er0+703.
00
24.
05
Pi
er0+483.
00
15.
25
-50
G=8
.
0
0
0
%
K 10.000
L 40.000m
Pi
er0+343.
00
9.
65
0
K 13.000
L 36.660m
G=4
.
0
0
0
%
G= 0.000%
Pi
er0+923.
00
24.
05
%
0
0
0
.
G= 0.000% G=4
PVI1+495.
287
El
ev 2.
600
PVI0+813.
000
El
ev 28.
449
K 13.000
L 52.000m
%
0
0
0
.
G=4
PVI0+020.
000
El
ev 2.
600
11/8/2011
kam -l
ung l
i
e
K 9.000
50
L 36.000m
Fi
l
enam e :
Pri
nted by :
J:\217093\Arup\CI
VI
L\217093-021.dgn
60
El
ev 6.
000
PVI0+105.
000
1:4000
1+250
1+500
Vertical Alignment Profile
1:4000
Consultant
Client
Ove Arup & Partners
Hong Kong Limited
Project
Feasibility Study
Drawing Title
General Layout of Bridge - Option 1
(Balanced Cantilever Box Girder)
Sheet 1 of 2
Drawn
Date
AL
C
ROUNDABOUTS ADDED
08/11
B
OPTION A2 REMOVED
08/11
A
FIRST ISSUE
07/11
Rev
Description
Date
Checked
Drawing No.
21/07/2011
Approved
DM
-
Scale
1:25000 on A3
217093/021
C
12.3m
0.5m
2m
7.3m
2m
Motorcycle
Lane
Carriageway
Motorcycle
Lane
Bituminous
Surfacing
C Bridge
L
C Bridge
L
F
a
l
l
l
l
a
F
Access opening
4.
4@ C
n Span
L M ai
5m
Sea Level
C Bridge
L
15
10
0
3.
5m
1
1
15
0
R
1
R
11 @ Suppor
tFace ofM ai
n Spanm
0.5m
1 - 1
1:100
Precast Spread Foundation
1m M i
n.
Sea Bed
5.2m
Closed chamber
2
1:500
1:100
38m
2m
Motorcycle
Lane
Carriageway
Motorcycle
Lane
0.5m
C Bridge
L
19m
21/7/2011
7.3m
F
a
l
l
l
l
a
F
In-situ
Slab
Precast
U-Beam
2 - 2
1:500
Approach Deck Typical Cross Section
Fi
l
enam e :
kam -l
ung l
i
e
2m
7m
1.
Pri
nted by :
J:\217093\Arup\CI
VI
L\217093-022.dgn
12.3m
Bituminous
Surfacing
2
Main Span Pier Front Elevation
Main Span Box Girder Cross Section
0.5m
C.J.
1:100
Consultant
Client
Ove Arup & Partners
Hong Kong Limited
Project
Feasibility Study
Drawing Title
(Balanced Cantilever Box Girder)
Sheet 2 of 2
Drawn
Date
AL
Checked
Approved
DM
A
Rev
FIRST ISSUE
Description
07/11
Date
Drawing No.
21/07/2011
-
Scale
1:500
on A3
217093/022
A
1
1
34
N
h
c
a
o
r
p
Ap
24
.
343.
0
CH
A
C
800
0+
= 887m sq.
2
35
600
0+
by roundabout
1
6
0+
400
Area occupied
e
g
d
i
nBr
i
Ma
C
A
A
A
000
+
1
0+
200
A
6.
4
Hulhumale
1
+
49
5
3.
2
C
40
30
C
CH
1
8.
2
1
+
40
0
Ap
p
r
o
a
c
h
At
Gr
a
d
e
CH .
1316.
0
.
79
.
0
C
5.
6
200
+
1
0+
000
Male
0
.
1283
CH .
At
Gr
a
d
e
Area occupied
B
by roundabout
= 887m sq.
+
A
10
8.
4
6.
8
Plan
1:4000
Approach
Main Bridge
W2
140m
W1
220m
220m
Notes:
Approach
E1
E2
220m
specified.
140m
33m
Airport Height
4.0m min.
headroom
4.
4m
CH .
343.
0
33m 33m 33m 33m 33m 33m 33m 33m
CH .
79.
0
24
(Alignment option A)
Navigation Channel
2. All elevations are in
metres above chart
datum.
CH .
1316.
0
3.
6
CH .
1283.
0
3
5
+1.2 M.H.H.W.
(170m x 12m)
Spread Foundation
Elevation
El
ev 2.
600
PVI1+495.
287
PVI0+813.
000
El
ev 23.
528
K=9.000
K=13.000
%
0
0
0
.
G= 0.000% G=4
K=13.000
G=4
.
0
0
0
%
%
0
0
0
.
G=4
G= 0.000%
K=13.000
G=2
.
8
2
0
%
G= 0.000%
-100
0+000
0+250
0+500
0+750
1+000
El
ev 2.
600
PVI1+385.
624
El
ev 7.
325
El
ev 6.
000
PVI1+218.
081
K 25.000
L 200.000m
K=10.000
PVI0+374.
801
-50
PVI0+020.
000
0
El
ev 2.
600
11/8/2011
kam -l
ung l
i
e
50
Fi
l
enam e :
Pri
nted by :
J:\217093\Arup\CI
VI
L\217093-026.dgn
60
El
ev 6.
000
PVI0+105.
000
1:4000
1+250
1+500
1:4000
Consultant
Client
Ove Arup & Partners
Hong Kong Limited
Project
Feasibility Study
Drawing Title
(Extradose)
Sheet 1 of 2
Drawn
Date
AL
C
ROUNDABOUTS ADDED
08/11
B
OPTION A2 REMOVED
08/11
A
FIRST ISSUE
07/11
Rev
Description
Date
Checked
Drawing No.
21/07/2011
Approved
DM
-
Scale
1:4000
on A3
217093/026
C
0.15m
0.15m
15.1m
2m
3.5m
Motorcycle
Lane
0.5m
2.1m
Carriageway
Bituminous
Surfacing
0.5m
C Bridge
L
3.5m
Carriageway
1
l
l
a
F
2m
C
L Bridge
Motorcycle
Lane
1.3m
C
L Tower
F
a
l
l
20.
4m
C
L Tower
20.
4m
2.29
1
2
2.6m
11.
3m
6.
5m
2
2.6m
3.
4m
1
Sea Level
2.4m
17.
6m
4.
4m
Access
opening
2.4m
Sea
Level
Sea
Level
Typical Deck Cross Section
1:100
Low Tower side
Elevation
5m
Stay
Cable
5m
1:500
3
3
Live
End
Seabed
Precast Spread Foundation
Closed chamber
1m M i
n.
Transverse Rib at
Cable Anchorage
1 - 1
C.J.
4
Seabed
1m M i
n.
Cable
Anchorage
4
1:100
High Tower Front Elevation
C
L Bridge
19m
C
L Tower
R
Web
C
0.
L Tower
1m
5m
21/7/2011
1:500
C
L Bridge
C
L Tower
C
L Tower
5m
Diaphragm
Fi
l
enam e :
kam -l
ung l
i
e
J:\217093\Arup\CI
VI
L\217093-027.dgn
38m
Pri
nted by :
High Tower Side Elevation
1:500
Consultant
4 - 4
2 - 2
3 - 3
1:500
1:500
1:500
Client
Ove Arup & Partners
Hong Kong Limited
Project
Feasibility Study
Drawing Title
(Extradose)
Sheet 2 of 2
Drawn
Date
AL
Checked
Approved
DM
A
Rev
FIRST ISSUE
Description
07/11
Date
Drawing No.
21/07/2011
-
Scale
1:500
on A3
217093/027
A
8
2
N
2
4
Approach
C
C
A
0+
.
57 60
6.
0 0
A
C
6
4
A
H
C
e
ad
Gr
At
App
r
oac
h
.1
7
5
7
.0
Mooring Cables
C
CH
A
pp
r
oa
ch
1
+
60
0
1
+
400
1
+
200
+
A
2
4
CH .
1526.
0
7
2
1
4
1
+
000
CH .
824.
0
Funadhoo
0+
800
CH .
791.
0
e
ad
Gr
t
A
C
0
80
+
1
1
.
5
30
e
g
d
i
gBr
n
i
t
a
o
l
F
CH
.
4
4
4
.
0
Anchorage
A
0+
400
of Pontoon
30
B
5
6
.
2
Mooring
951
+
1
5
4
3
4
6
.
2
A
2
C
1
5
Cables
3
4
9
.
0
2
+
Fl
oat
i
ng B
r
i
dge
6
4
0+
200
0
4
Hulhumale
3
4
3
4
50
5
4
2
4
2. Seabed profile shown in
plan is based on admiralty
chart.
CH
.
4
1
.
0
AtG
r
ade
B
21/7/2011
kam -l
ung l
i
e
20
0+
000
Notes:
specified.
Male
2
5
30
Plan
Fi
l
enam e :
Pri
nted by :
J:\217093\Arup\CI
VI
L\217093-031.dgn
5
4
2
.
8
1
(Alignment Option C)
1:4000
Consultant
Client
Ove Arup & Partners
Hong Kong Limited
Project
Feasibility Study
Drawing Title
(Floating Bridge)
Sheet 1 of 3
Drawn
Date
AL
Checked
Approved
DM
A
Rev
FIRST ISSUE
Description
07/11
Date
Drawing No.
21/07/2011
-
Scale
1:4000
on A3
217093/031
A
Floating Bridge
50
El
ev 6.
600
CH .
576.
0
CH .
444.
0
CH .
41.
0
100
PVI0+535.
500
33m 33m 33m 33m At Grade
El
ev 6.
600
End Module
PVI0+129.
956
2-Span Module
El
ev 2.
600
End Module
Approach
PVI0+000.
000
At
Grade
K=13.000
%
0
0
0
.
G=4
G= 0.000%
K=13.000
G=4
.
0
0
0
%
G= 0.000%
G= 0.000%
Cable
Anchorage
-100
0+000
At Grade 33m
0+250
0+500
Elevation
1:4000
1:4000
Approach
Floating Bridge
End Module
Approach
5-Span Module
End Module
33m 33m 33m 33m 33m 33m 33m At Grade
Airport Height
Notes:
CH .
1757.
0
CH .
1526.
0
CH .
824.
0
CH .
791.
0
99.6m
1. All dimensions are in metres
unless otherwise specified.
2. All elevations are in metres
above chart datum.
+0.6 M.S.L.
Navigation Channel
Pontoon
El
ev 2.
600
-50
Mooring
K=10.000
K=10.000
PVI0+635.
500
Pontoon
El
ev 2.
600
PVI0+029.
956
0
+0.6 M.S.L.
(70m x 8.5m)
Anchorage
K=13.000
G= 0.000%
G=4
.
0
0
0
%
K=10.000
El
ev 6.
600
PVI1+320.
000
K=10.000
El
ev 6.
600
PVI1+030.
000
El
ev 2.
600
K=10.000
G= 0.000%
El
ev 2.
600
G= 0.000%
PVI1+820.
851
%
0
0
0
.
G=4
G=4
.
0
0
0
%
%
0
0
0
.
G=4
0
-50
K=13.000
K=13.000
K=13.000
El
ev 2.
600
El
ev 6.
600
PVI1+950.
581
1:4000
PVI1+720.
851
PVI1+175.
000
50
PVI0+729.
340
J:\217093\Arup\CI
VI
L\217093-032.dgn
Fi
l
enam e :
21/7/2011
kam -l
ung l
i
e
Pri
nted by :
100
Elevation
Cable
El
ev 6.
600
PVI0+829.
340
Mooring
El
ev 12.
400
-100
0+750
1+000
1+250
1+500
1+750
2+000
1:4000
Consultant
Client
Ove Arup & Partners
Hong Kong Limited
Project
Feasibility Study
Drawing Title
(Floating Bridge)
Sheet 2 of 3
Drawn
Date
AL
Checked
Approved
DM
A
Rev
FIRST ISSUE
Description
07/11
Date
Drawing No.
21/07/2011
-
Scale
1:4000
on A3
217093/032
A
C
L Pontoon
100.3m
C
L Pontoon
100.3m
99.6m
C
L Support
99.6m
End
C Support
module L
C
L Pontoon
12.9m
End
Support C
L module
Mi
n.
5m
Sea Level
Elevation
Fixed connection between
Deck and Pontoon at all supports
Top plan bracing
8.
8m
1:1000
2m
7.3m
2m
Motorcycle
Lane
Carriageway
Motorcycle
Lane
0.5m
0.5m
Steel plate
deck with
longitudinal
stiffeners
Bituminous
Surfacing
F
a
l
l
l
l
a
F
Plan
1:1000
Steel cross beam
at 4m centres
2-Span Module (5-Span Module Similar)
C
L Bearing
Typical Deck Cross Section
C
L Pontoon
100.3m
1:100
Bearing C
L
99.6m
Sea Level
12.9m
Elevation
C
L Bridge
J:\217093\Arup\CI
VI
L\217093-033.dgn
kam -l
ung l
i
e
Pri
nted by :
Top plan bracing
16.5m
9-compartment
concrete pontoon
1
10.
25m
7.
4m
1
Var
i
es
C
L Pontoon
C
L Pontoon
1m x 3m
column
33m
6.45m
1:1000
Consultant
Client
Ove Arup & Partners
Hong Kong Limited
1:500
1:500
Project
Feasibility Study
Drawing Title
(Floating Bridge)
Sheet 3 of 3
C
L Support
1 - 1
Typical Section at Support
End Span Module
6.45m
C
L Support
Plan
Fi
l
enam e :
21/7/2011
1:1000
C
L Bridge
16.5m
10.
25m
Bearing
Support
8.
8m
Bearing
Support
Drawn
Date
AL
Checked
Approved
DM
A
Rev
FIRST ISSUE
Description
07/11
Date
Drawing No.
21/07/2011
-
Scale
1:800
on A3
217093/033
Appendix B
Artistic Images
Balanced Cantilever Bridge on Alignment Option A
Balanced Cantilever Bridge on Alignment Option A
Extradosed Bridge on Alignment Option A
Extradosed Bridge on Alignment Option A
Floating Bridge on Alignment Option C
Floating Bridge on Alignment Option C

GADL International Ltd Feasibility Study for Construction of a Bridge

Transcription

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