THE CORE-LOC ARMORING TECHNIQUE EXPERIENCE

THE CORE-LOC® ARMORING TECHNIQUE
EXPERIENCE ON RECENT PROJECTS
David J. Werren1, William F. Baird1, Michel Denechere2 and Michel Fons2
Abstract: This paper discusses recent experience with the application of the
Core-Loc® armor unit. Practical issues associated with implementation of CoreLoc® as the armor unit on breakwaters are discussed, including stability, placement technique, packing density, the toe and the crest details.
INTRODUCTION
The Core-Loc® armor unit is the result of many years of research at the U. S. Army
Corps of Engineers (USACE) Waterways Experiment Station (WES), Coastal and
Hydraulic Laboratory (CHL), (Melby and Turk 1996, 1997, Turk and Melby 1998) that
has involved two- and three-dimensional hydraulic model studies, measurement of
internal stresses using load cell based procedures and analysis of the distribution of
stress in the unit using finite element methods.
The Core-Loc® unit is intended to be placed in a single, armor layer on a breakwater
or revetment and may be considered as an advanced or refined version of an Accropode®
unit. Core-Loc® units have also been designed to repair damaged Dolos breakwaters
(Turk and Melby, 1997).
1 Principal, W. F. Baird & Associates, 2981 Yarmouth Greenway, Madison, WI 53711 USA.
[email protected]
2 Principal, W. F. Baird & Associates, 1145 Hunt Club Rd., Suite 500, Ottawa, ON K1V 0Y3
Canada. [email protected]
3 Core Loc® International, Pole 1, 3,cour du 56, av. M. Dassault Tours 37200 France.
[email protected]
4 Sogreah Maritime, Patents and Trademarks Division, 6 rue de Lorraine - 38130 Echirolles, BP
172 Cedex 9, Grenoble, 38042 France.
1
Werren, Baird, Denechere, and Fons
Physical model tests have shown that superior hydraulic stability is achieved with
the symmetrically-tapered octagonal flukes, and stress analyses have demonstrated
improved strength characteristics compared to the Accropode®. Consequently, the
Core-Loc® unit has significant economic advantages compared to other concrete
armor units with equivalent performance.
This paper discusses practical issues related to the construction and placement of
Core-Loc® units and addresses some overall breakwater design and construction issues.
Ten projects have recently been completed or are under construction with the involvement of the authors. These projects involve approximately 330,000 cubic meters of
concrete and over 120,000 Core-Loc® units varying, so far, from 0.5 to 9 cubic meters in
size.
BACKGROUND
The Core-Loc® Concrete Armoring Unit was developed by the USACE, Coastal
Hydraulics Laboratory. The Principal Investigators were Dr. Jeffrey Melby and Mr. George
Turk. The USACE undertook considerable research and development on the unit including
a number of generalized model studies in order to develop design information. In addition,
the USACE took out patents and trademark protection to license the technology around the
world. The USACE then contracted with a number of private organizations to manage the
various licenses required under the patents and trademarks. The purpose of this licensing
arrangement was to assure that the technology was applied appropriately, as well as to
charge and collect a royalty for the use of the units. This royalty money then flows back to
the USACE to provide additional funds for research both on the Core-Loc® and other
similar concrete armor units.
As a part of the licensing process, two of the sub-licensees (W. F. Baird & Associates
and Sogreah) established a company to manage the licensing and quality assurance
activities of Core-Loc® in their territories. This new company is called Core-Loc International, or CLI for short. CLI has been structured to include a repository of information
about Core-Loc®, both in the design and construction phases, to assist designers and
contractors in the implementation of Core-Loc® projects. It is the belief of the authors and
the stated objective of CLI that future coastal structures need to be developed from a
dynamic and managed knowledge base accessible to all designers. “Knowledge-based
solutions” benefit from past experience and provide the best performing coastal structures
at the most practical cost. CLI will make this best current practice information available on
its website: www.coreloc.com.
SPECIFIC ISSUES LEARNED ABOUT CORE-LOC®
One of the key project elements experienced by the authors has been the importance of
the preparation of the underlayer, or filter stone, prior to receiving the Core-Loc® units.
Although model studies and field experience show good performance of the CoreLoc®units placed over a range of prepared underlayer tolerances, it is found that the
placement of the single layer of Core-Loc® units is much easier, and higher production is
achieved, if adequate care is taken to prepare the underlayer with minimal variation from
the specified line and grade. The generalized specification for Core-Loc® is that any one
survey line should not vary more that one-sixth of the “C-dimension” of the Core-Loc®, nor
2
Werren, Baird, Denechere, and Fons
should the surface vary more that one-tenth of the “C-dimension” for an average of three
consecutive survey lines. We have generally found that contractors who meet or improve
upon these tolerances achieve better production rates during the placement of the CoreLoc® units.
Experience on the projects to date has shown that there are two approaches to placing
the Core-Loc® units. While the preferred method is to place the units each with a random
orientation on an organized grid pattern, they can also be placed with random orientation in
a random placement pattern on the slope. The latter is particularly useful in areas of small
placement where the establishment of a grid and the purchasing of global positioning
equipment to assist in an organized grid placement is cost prohibitive. A diver is required to
assist with placement of all underwater portions. It is found that placing the units underwater on an organized grid with carefully controlled locations, reduces the effort and time
required by the diver to both assist and verify that the unit is placed correctly. Therefore, it
has been concluded that grid placement is preferred over the random-placement approach,
except in those areas where the work can be observed (such as above water), or if the units
themselves are very small, and the grid pattern is difficult to achieve because of its small
size. In any event, even with the random placement, an attempt should be made to achieve
an organized placing pattern such that each row of units is placed staggered above the
previous row, and without Core-Loc® units in the same row touching each other.
The USACE guidelines addressing the packing density of the Core-Loc® units have
been found to provide both stability in hydraulic model studies as well as good interlocking
in prototype experience. Most of the structures constructed to-date have had packing
densities of between 0.57 and 0.60. It is generally easier to achieve a higher packing density
with smaller units during the prototype construction. Packing density needs to be very
carefully monitored both in the hydraulic model studies and in the prototype construction. If
the units are being placed on a regular-grid placement where the position of each unit is
known, the packing density can be easily controlled. However, if random placement is used,
the packing density needs to be checked very frequently to assure that there are no areas of
the structure that have been placed to a sub-standard density.
A significant amount has been learned about optimizing both the toe and crest details of
Core-Loc® breakwaters. There are a number of options for the toe construction using the
Core-Loc® unit. One option is that in the first row the units sit on two lower flukes in what
is known as a “cannon position”. It is found that contracting and placing crews like to place
the lowest unit in this position because it is relatively easy to control and visually verify that
it is placed correctly. A number of variations can be made following this first row “cannon
position” placement. The first option is to begin random orientation of units immediately
above the cannon-placed units in the first row at the toe. The second option is to place one
or two regularly-oriented units specifically above the cannon units to interlock them prior to
placing the randomly-placed units on the slope. Again, it has been found in prototype
experience by several contractors that, the placing crews prefer to place the units in a
regular pattern near the toe because it assists the diver during the placing operation and
provides a rapid visual verification that the units are well interlocked (and that the density
has been met.) It is, however, more difficult to orient large units in deepwater conditions.
Model studies have been completed with both randomly-oriented units and with an
3
Werren, Baird, Denechere, and Fons
organized cannon-placement method. Both configurations have been found to provide very
stable structures. It is our opinion that the most critical factor with respect to toe placement
is that the toe units extend low enough to the sea floor, and are not placed on a rock-berm
or rock-support partly up the slope. This is because it is difficult to place the first units
against an armor stone slope at the toe and assure that they are well nested and solid. The
concern being the overlying units are relying on the lower or first row units not shifting or
moving. If these units are placed on large armor-stone buttresses, there is a potential that
during the first storm event these units may shift and settle into a lower position within the
armor stone, allowing the units on the slope to shift downslope.
With respect to crest details, it is very important to consider how the crest of the
breakwater will be finished. On several projects, the Core-Locs® have been finished against
a fixed crown-wall structure. Initially, there was a concern that trying to establish a fixedor oriented-grid pattern against a fixed-structure such as a crown wall would create
problems. However, it has generally been found that there are enough opportunities to
adjust the units above the waterline such that a tight fit between the crown wall, and the
front slope can be achieved. In areas where access to the top of the breakwater is not
required, the Core-Loc® units have generally been extended across the top of the breakwater
and down the lee side breakwater at least to the low waterline. The primary issue found in
this application is that the units in the crest of the breakwater are more difficult to place
than those on the slopes of the breakwater. This is due to the fact that while placing the
Core-Loc® on the slope of a structure, gravity assists the placing operation and a good
interlock can be achieved. On a horizontal surface such as the crest, there is no gravity
assistance. There is a natural tendency for the units to want to sit in a cannon position, and
they can either be placed too loosely (i.e., not meeting the required packing density) or too
tightly by stacking them as found in a casting yard where they are nested together very
tightly. The best experience has been to undertake several test sections and work with the
contractors to achieve a placement pattern that provides good unit-to-unit contact without
excessive consumption of concrete.
The casting of Core-Loc® units is generally found to be both straightforward and has
been without problems in all projects completed. The forming process uses a two-piece
mold with a vertical seam. It has been found that using a two-piece mold with wheels on
the mold allows the forms to be removed from the units without the use of a crane or
equipment. A wide range of experience has been observed with respect to the speed of the
casting process. In general, it has been concluded that very successful production operations
can be achieved by obtaining one pouring of a Core-Loc® unit per-day per-mold.
PROJECT EXPERIENCE
The following projects illustrate the representative experience of Core-Loc® along
with a range of examples with experience about specific details discussed above.
Although these projects show a number of possible alternatives with respect to CoreLoc®, because of the significant learning curve for each of the projects, we caution that
there may be methods depicted for these individual projects which would not be recommended on future projects of a similar nature.
4
Werren, Baird, Denechere, and Fons
Khaboura, Oman
This project consisted on an offshore breakwater with a pile-supported structural pier
servicing a small fish-loading facility behind the breakwater. This structure was designed
by Baird & Associates and Cansult for the Ministry of Agriculture and Fisheries in Oman.
The toe of the structure was located in a water depth of -3.5m below datum. There were
design issues related to the ongoing erosion of the surrounding seafloor, so the structure
was designed for eventual downcutting of the seafloor and deeper-water conditions at the
structure. In addition, because of the relatively short length of the breakwater, the CoreLoc® units were sized assuming the head condition, or a Kd of 12 rather than the published
Kd of 16 for trunk section. Given the small size of the structure, it was concluded that
utilizing two separate sizes of Core-Loc® was not justified. This was one of the first CoreLoc® projects implemented and it was left to the contractor whether they wanted to use a
random-placement pattern or use a grid orientation. The number of test sections were built
and the contractor elected to proceed utilizing a random-placement method.
Photograph 1
Photograph 2
Photograph 1 shows the construction of the offshore breakwater. The pile supported
access way in the center of the photo, and a temporary construction access road of rock fill
on the right-hand side of the pile-supported trestleway.
As noted above, random placement was utilized for the Core-Loc® in this project. A
total of 2, 500 Core-Loc® were utilized in the project each being 3.0 cubic meters in size. In
this case, the casting was achieved by the utilization of seven molds, in a controlled casting
yard. Because of the controlled conditions for casting units, the molds were used two times
per day, with very good success. Placement of the units in the structure was relatively slow,
at a rate of approximately four-to-six units per hour once the crane operator and diver
became experienced with the procedure (photograph 2). The placing crew followed three
basic rules in the placement process: 1) the units must always rest on the prepared underlayer surface and not be supported strictly by the adjoining Core-Loc® units; 2) each CoreLoc® unit when placed had to interlock and constrain the units below it; and 3) the placing
density was checked frequently by calculating the area of coverage and the number of units
placed and that the density met the placement density specification of 0.60. Placement of
the units started by placing the toe rows, and then building a pyramid or triangular section
on the face of the slope from the toe. Placing then worked from the toe up the 45° degree
slope of previously placed units to a level above the water surface.
5
Werren, Baird, Denechere, and Fons
Photograph 3
Photograph 4
Photograph 3 shows the finished face of the Khaboura breakwater structure. Although
the placement pattern was random, it was noticed that after some time a more regular
pattern of placing appeared as a result of the experience of the placing crew. Generally it
was found that once the crew established a certain degree of comfort and experience in the
placing operation they preferred to place the units in a more regular pattern although they
were encouraged to maintain a random orientation in the individual units placed.
Dhalkut, Oman
This project was designed by Scott Wilson and was also for the Ministry Agriculture
and Fisheries in Oman. This is a fisheries harbor, with a secondary objective of providing a
harbor refuge for small coastal patrol vessels. The site is located in a very remote location,
at the southwestern end of Oman near the border of Yemen. The project is subject to a
depth-limited breaking wave climate; a severe wave climate is experienced each year as a
result of the annual monsoon. In total in this location over 64,000 Core-Loc® units were
used, ranging in size from 3.9 to 9 cubic meters. The slopes on the outboard face of this
structure were 1.5:1, except at the head of the structure where a slope of 2:1 was utilized
along with the 9 cubic meter Core-Loc® units. This project was tested at HR Wallingford in
the UK (Lee, Allsop, and Baird, 2000.) We are considering with future model studies
whether or not there are any stability advantages in decreasing the slope at the head of the
breakwater. Certainly there are some advantages in maintaining the steeper slope.
A number of design issues came up during the design of this project. These included
exposed rock at the head of the breakwater structure. The seafloor at the head consisted of
generally smooth rock floor and it was determined in the model study that this could lead to
an instability in the Core-Loc® units on the inside of the head of the structure at the toe. In
addition to the exposed rock and extreme wave conditions, the structure had to be designed
such that it could be built over two construction monsoon seasons. This meant that the
structure had to be partially completed and survive the monsoon during the construction
period. The contractor worked with HR Wallingford to develop a monsoon closedown
procedure utilizing Core-Loc® to protect the temporary facility.
Photograph 4 shows the 6.75 cubic meter forms during the casting process. The twopiece form units, split vertically, with form half-supported by a wheel assembly can be
seen. The forms are extracted by applying pressure at the nose of the horizontal fluke and
removed relatively easily from the finished Core-Loc® unit.
6
Werren, Baird, Denechere, and Fons
Photograph 5
Photograph 6
Photograph 5 shows a completed 9 cubic meter Core-Loc® unit. It can be seen from the
photograph that a very high quality has been achieved during casting of the unit with very
little loss of water from the form at the joint and no honeycombing or visual surface
damage on the finished Core-Loc® unit.
In photograph 6 the prepared underlayer slope, as the initial Core-Loc® units were
placed on the structure, can be seen. The units being placed in this photograph are 3.9 cubic
meters. The very high quality of the underlayer preparation provided significant assistance
to the contractor in achieving rapid placement of the Core-Loc® units. Again, as with
Khaboura, the contractor elected to utilize random placement of the Core-Loc® units on the
structure rather than following a specified grid pattern.
Photograph 7 shows the head of the completed Dhalkut breakwater consisting of 9 cubic
meter units at a 2:1 slope. The crest of this breakwater is at approximately +10 meters CD
in elevation and the
toe at the outside of
this breakwater is
approximately -8
meters CD for a total
structure height of 18
meters. Although the
breakwater was initially
tested at a 2:1 slope
and found to be stable,
it is the opinion of the
authors that perhaps
this structure would be
Photograph 7
7
Werren, Baird, Denechere, and Fons
as stable on a 1.5:1 slope as on a 2:1 slope. This is an area in which CLI will be doing
additional research; however, it is our initial observation that decreasing slopes do not
necessarily provide increased stability, as is suggested by the Hudson equation when
utilizing Core-Loc® units. The Core-Loc® units obtain a significant degree of their interlock
and stability by the weight of the overlaying units providing the force of interlock.
As mentioned, the other concern and design difficulty at this site was the exposed rock
seafloor at the head of the structure. Initially, excavation of a trench into the rock was
considered. However, because of environmental concerns related to the local lobster
fishery, blasting of the rock was extremely difficult and limited to a very few weeks per
year. Therefore, a toe detail was developed, in which the Core-Loc® units extended to the
seafloor and rested on a row of cannon-placed Core-Loc® units. These cannon-placed units
rested on a thin bedding layer immediately above the smooth rock seafloor. In front of the
cannon units was a wide berm of armor stone units a single-layer thick placed around the
toe of the structure. This armor stone berm was then choked, by divers using grout bags,
and prepared to receive a tremy grout. Once the outer edge of the armor stone layer was
choked, concrete was pumped in filling the voids in the entire armor stone berm, and filling
the first Core-Loc® unit to about two-thirds their depth in concrete. This provided a single
massive toe, with the first row of Core-Loc® protruding slightly above the tremied mass.
The transition between the1.5:1 outboard slope and the 2:1 slope of the finished head of
the structure can be observed. In this transition area, the size of the units also make a
transition from 6.75 to 9 cubic meters. Although this transition represents a significant
increase in the size of the units, it is very difficult to observe the transition in the field as the
units have achieved an excellent interlock even through a size and slope transition. It has
been generally found that changes in size of units up to 100-percent can be easily achieved
at a transition area as the Core-Loc® units provide exceptional interlock capabilities through
various size ranges.
The breakwater was constructed at a lower elevation initially allowing a wider width for
construction ac-cess.
All construc-tion was
done as a land-based
opera-tion.
Photograph 8 shows
the completed breakwater structure at
Dhalkut.
Photograph 8
8
Werren, Baird, Denechere, and Fons
Sohar, Oman
The port at Sohar is a large commercial port designed by Halcrow. This is a project for
the Ministry of Communications of Oman. In total, over six kilometers of breakwaters were
constructed consuming over 150,000 cubic meters of concrete. The Core-Loc® sizes ranged
from 0.5 to 3 cubic meters. In total, over 80,000 Core-Loc® units were utilized in the
structure. This structure was originally designed by Halcrow to utilize the Stabit armor unit.
The Core-Loc® units were proposed as an alternative, and eventually accepted by the Owner
and Halcrow. The contractor was Daewoo Construction of Korea. The contractor submitted
the Core-Loc® alternative as a cost-savings measure, and significant cost savings were
achieved.
Photograph 9
Photograph 10
Because of the large number of units required for this project, a very organized casting
procedure was required. In photograph 9 an elevated roadway prepared by the contractor to
assist in the casting process can be seen. Utilizing standard concrete trucks on the elevated
roadways, the concrete was discharged directly from the truck into the forms without
pumping. Each form was used once-per-day. After pouring, the forms were stripped
approximately 12 to18 hours later and prepared for the next day’s pouring. The casting yard
was prepared on the concept of three Core-Loc® per-casting-station. At a casting station, the
forms were located and the current day’s pour was made. This allowed room for two
additional Core-Loc® units; one was the previous day’s pour and the third unit was from
two days prior. The third unit was removed on the third day, and the forms, once stripped
from the freshly poured unit, were moved into the third position. This allowed a totalcuring time of between 2 to 3 days for each Core-Loc® unit before it was initially moved.
The units were lifted from the casting area using a forklift with padded forks.
Photograph 10 shows the vibration process after pouring, as well as the storage area of
the Core-Loc®. It was found with a particular mixed design, using Type V Cement, at Sohar
that after the initial vibration and filling of the units, some plastic settling of the concrete
occurred, which generated bleed-water at the edge of the forms. It was found that by revibrating the forms after a period of 30 to 60 minutes, depending on the temperature
conditions, that the plastic settling and the water problem could be eliminated. The end
9
Werren, Baird, Denechere, and Fons
result was a very high quality consistent Core-Loc® with an extremely low number of units
rejected due to manufacturing defects.
Again because of the large number of units involved the system of form-removal and
curing of the units was highly organized. Compressed-air lines serving the casting area
allowed the rapid application of curing compound immediately upon removal of the forms.
Because adequate storage room was available, the Core-Loc® units were stored on the
project's site, without stacking.
Photograph 11
Photograph 12
For this project a specific project placing grid was utilized. A placing grid was prepared
in AutoCad based on the underlayer drawings. This placing grid established an X, Y,
position for each of the 80,000 Core-Loc® units to be placed. At the beginning of each work
shift, the day's work was programmed into the Global Positioning System (GPS) that was
used to control the placement of the units (Photograph 11). In addition, a placing chart
showing all the locations was taken out to the work crew doing the work. In this way, the
work crew could track the location of each unit placed in the previous day’s work, the units
to be placed during the current workday, and the actual work completed that day. Each of
the coordinates for each unit was preprogrammed into the data collector. Each unit also had
a specific and unique number. As the operators entered the unit number, the grid coordinates would be displayed along with the actual position of the crane and the target location
for the units. This system proved to be extremely effective allowing very rapid placement of
the units.
Photograph 12 shows a prepared underlayer slope with the Core-Loc® placement
advancing.
10
Werren, Baird, Denechere, and Fons
Photograph 13
Photograph 14
Photograph 13 is a view of the northerly breakwater taken from the entrance to the
harbor. In this picture the placing crane can be seen working from a barge placing CoreLoc® units on the front face of the breakwater. This operation is being undertaken by only
the crane operator, and one spotter-assistant who is working on the front face of the
structure. It is not possible for the crane operator to see the placing position even though the
units are above water. However by using the GPS placing system, this operation achieved
very rapid placing rates, with excellent results.
Photograph 14 shows the tower crane that was utilized at the head of the breakwater. The
tower crane was utilized because the head of the breakwater was designed to extend into the
dredged entrance channel into the port. Therefore, the toe of the structure extended into -16
meters CD of water, and resulted in very long slopes with a long reach. The tower crane
proved to be an effective tool in reaching the long slopes to place the Core-Loc®.
Photograph 15 shows a
view of the southerly
breakwater structure. The
Core-Loc® units are fit up
against the crown-wall
structure and although
placed on a regular
pattern, it was found that
the units were relatively
easy to maneuver in the
last two to three rows in
order to achieve a tight fit
against the crown-wall
structure. In this view,
Core-Loc® units on this
breakwater are three cubic
meters.
Photograph 15
11
Werren, Baird, Denechere, and Fons
Saham, Oman
The Saham Fishery Harbor was another project for the Ministry of Agriculture and
Fisheries in Oman. The designer of this project was Scott Wilson. As this is a relatively
small fishing port in protected waters, the size of the units ranged from 1.3 to 2.0 cubic
meters. In total, approximately 16,000 cubic meters of concrete were utilized, with a total of
approximately 12,000 Core-Loc® being
cast. In this case, the contractor elected
to utilize random placement of the CoreLoc® units. This was largely due to the
fact that the water depths were relatively
shallow, and after the initial first two or
three rows of the Core-Loc®, at low tide
the Core-Loc® units could be seen from
the surface.
Photograph 16 shows a view of the
Saham Fishery Port under construction.
Photograph 16
Photograph 17 shows a problem that occurs with specified random placement. Although
the concept of random placement had been discussed in detail with both the placing crew
and the contractor, it is difficult to convey the full intent of random placement. This
photograph was taken after an initial placement of Core-Loc® had been attempted. The
placing crew thought they were achieving a good interlock of units in this fashion. After
explaining that this did not provide a good interlock and was something to be avoided with
Core-Loc® units, the placing pattern was subsequently modified. This type of placing
pattern should most definitely be avoided and does not provide the stability that needs to be
achieved with Core-Loc® units.
Photograph 17
Photograph 18
Photograph 18 shows the finished crest of the Saham breakwater. Because this was a
relatively low crested but wide structure, some difficulty in finding the best method to place
the units at the crest was encountered. As noted previously, the difficulty is that gravity
does not assist the interlock between the units, and the units must be placed in a manner
that prevents rocking during an overtopping event. This takes some degree of work between
the contractor and the on-site representative crew to establish the best methodology to place
12
Werren, Baird, Denechere, and Fons
the units in order to achieve good interlock without using excessive consumption of
concrete by nesting the units back-to-back.
CONCLUSION
The Core-Loc® armor unit has been used on many projects. With each project, new
experience is gained that will assist new Core-Loc® projects achieve both stability and ease
of construction.
In general, it has been found that the prototype construction has proceeded extremely
well and the unit has demonstrated that it can be readily adapted to site-specific issues that
arise. Contractors have reported that the casting and placing process has gone well, and the
unit has met their needs and expectations.
Clearly, there is a significant amount yet to learn. The establishment of a dynamic
knowledge base, accessible to designers, is believed to be of critical importance by
providing the most up-to-date and current design practice. This database will be available
in a web-based environment at www.coreloc.com. While Core-Loc® is not for every
project, it has demonstrated that it is both a robust and economical solution when appropriately used.
REFERENCES
Lee, T.H. Allsop, N.W.H. and Baird, W.F., The Laboratory Results of Core-Loc performance at Sohar Breakwater, Sultanate of Oman, Korea-China Conference on Port and
Coastal Engineering, September 2000, Seoul, Korea.
McHale, J., O’Loan, D., Denechere, M. and Fons, M., First Application in Europe of the
CORE-LOC™ Technique at Tory Island, Republic of Ireland Coastlines, Structures
and Breakwaters September 2001, London. Marine & Natural Resources, Ballyshanon,
Ireland – Kirk Mc Klure Morton, Belfast, Ireland – Sogreah, Echirolles, France.
Melby, J.A. and Turk, G.F. 1996. Core-Loc Development as Related to Historical Corps
Concrete Armor Unit Performance. Proceedings of Advances in Coastal Structures
and Breakwaters, London, England, April 27-29, 253-267.
Melby, J.A. and Turk, G.F. 1997. Core-Loc™ Concrete Armour Units: Technical Guidelines, U.S. Army Corps of Engineers, Waterways Experiment Station, Technical Report
CHL-97-4.
Turk, G. and Melby, J.A. August 1997. Preliminary 3-D Testing of CORE-LOC™ as a
Repair Concrete Armor Unit for Dolos-Armored Breakwater Slopes, Technical Report
REMR-CO-18.
Turk, G. and Melby, J.A. 1997 Dynamic Structural Response of Core-Loc™. The REMR
Bulletin, Vol. 14, 3.
Turk G.F., Melby J.A., 1998 Impact structural response of Core-Loc™. Proceedings 26th
Coastal Engineering Conference V.2, ASCE, Reston, VA, 1846-1856.
13
Werren, Baird, Denechere, and Fons
®
THE CORE-LOC ARMORING TECHNIQUE
EXPERIENCE ON RECENT PROJECTS
David J. Werren1, William F. Baird1, Michel Denechere2 and Michel Fons2
KEY WORDS
armor
breakwater
concrete
construction
Core-Loc®
knowledge base
revetment
single layer
stability
14
Werren, Baird, Denechere, and Fons