ci9- V950

Transcription

ci9- V950

ci9- V950
CLASSIFICATION NOTES
No. 32.2
CONTAINER SECURING
AUGUST2003
DET NORSKE VERITAS
Veritasveien 1, N-1322 H~vik, Norway Tel.: +47 67 57 99 OU Fax: +47 6757 99l1
FOREWORD
DET NORSKE VERIT AS is an autonomous and independent Foundation with the objective of safeguarding life, property and
the environment at sea and ashore.
DET NO RS KE VERITAS AS i.., a fully owned subsidiary Society of the Foundation. It undertakes classification and certification
of ships, mobile offshore units, fixed offshore structures, facilities and systems for shipping and other industries. The Society
also carries out research and development associated with these functions.
DET NORSKE VERIT AS operates a worldwide network of survey stations and is authorised by more than 130 national admin istrations to carry out surveys and, in most cases, issue certificates on their behalf.
Classification Notes
Class1hcat.1on Notes are publications that give practical information on classification of ships and other objL'Cl<;. Examples of design solutions, calculation methods, specifications of test procedures, as well a'> acceptable repair methods for some components
are given as interpretations of the more general rule requirements.
A list of Classification Notes is found in the latest edition of Pt.O Ch.1 of the "Rules for Classification of Ships" and the "Rules
·
for Classification of High Speed, Light Craft and Naval Surface Craft".
The list of Classification Notes is also included in the current "Classification Services - Publications" i..,sued by the Society,
which is available on request. All publications may be ordered from the Society's Web site http://exchange.dnv.com.
Amendments and Corrections
The l'IUlin changes are:
The increasing size of container ships and introduction of new requirements, such as OSHA requirements etc, have led to a rapid
technical development within the field of container securing.
DNV have during the past years developed new analysis methods to account for these developments thal have not yet been inc luded into the published guidelines.
Due to this the Classification Note for container securing (CN 32.2) has been completely revised to include the recent development.
The changes can be summarised under the following headings calculation methods, guidance to specialised stowage and acceptance criteria.
Calculation methods
The Classification Note co ntain the formula based calculation method as given in the existing class note as well as a detailed
description of the new calculation method utilised in the "NAUTJ.CUS Container securing" software. These two analysis methods are considered equivalent however the new method is more general and can be used for a wider range of stowage arrangements.
In addition to these calculation methods a calculation method for mixed stowage is given (with and without over stow).
Specialised stowage
For specialised stowage types additional guidance is required in order to perform the analysis and in addition some stowage arrangements cannot be analysed with !-ltandardised analysis methods. To cope with these problems a new chapter have been introduced where guidance for stowage types such as the following is given:
Mixed stowage (20' containers in 40' cellguides and 40' containers in 45' cellguides)
Lashing to lashing bridge
Vertical lashings
Platform containers
Block stowage
Acceptance criteria
Some minor changes to the acceptance criteria will be introduced in the new Classification Note.
The allowable forces on the contai ner box have been slightly revised to allow forces in excess of the ISO test criteria, this revision
have been done to be aligned with the industry standard.
In addition a list of guidance values for allowable forces on lashing equipment has been added.
Comments may be sent by e-mail to [email protected]
For .c;uhscription orders or information about subscription terms, please use dilui'[email protected]
Comprehensive information about DNV and the Society's services is found at the Wch site http://www,<lny,com
© Det Norske VeritaR
Computer Typeseuing (F1vl+SGML) by Oet Non;ke VcritaR
Printed in Norway.
If any person suf!e.s 10$6 or damage which is ptcwed 10 have been caused bf any negligenl acl or oml.9sion ot Del Norske Verilas, then Del Norske Verilas snaW pay C()lllpensalicrl lo &UCh person
for his proYed dlrllGI loss or daml>ge. HOW41ver, lhe compensatton shal not exceed an amount equal lo ten times the tee charged'"' Ille S9fVice in question, provided lhal the maxmum compen·
aalion shad ™Iller exceed USO 2 million.
In this provision "Det Norsk& Ventas· &hall mee.n lhe Foundation Oet Nolske Verb s as well as an ils 61.bsidiaries, cirectors, orflCOOI, employees, agents and any other eclflg on behalt ol Det
NOr$k8 Veritas.
Classification Notes - No. 32.2
3
August 2003
CONTENTS
1.
I. l
l.2
1.3
1.4
2.
2.1
2.2
2.3
3.
3.1
3.2
3.3
3.4
3.5
4.
4.1
4.2
4.3
4.4
5.
5.1
5.2
5.3
5.4
5.5
6.
6.1
6.2
6.3
6.4
GENERAL ....... ,, ....... ,............................................ ,... 4
Introduction ....... ................................................. .......... 4
Procedure .......................................... ........................... 4
Definitjons .................................................. .................4
Assumptions ................................................................5
DESIGN J,O ADS ...................................................... 5
General .. .................................. ..................................... 5
Wind load ..................................................................... 5
Acccleralions ...... ... ....... ................................ ............... 5
LOADING CONDITIONS ...................................... 5
Gcneral .............................. ........................................... 5
LC1: Transverse loading I ................................... ........ 5
LC2: Vertic;al loading ............. .....................................6
LC3: Transverse loading II ........ .................................. 6
LC4: Longitudinal loading ..........................................6
ACCEP T A NCR CRITERIA .................................... 6
General .............. ........................................................... 6
Container box ............................................................... 6
Container securing equipment ..................................... 7
Ship s lructure ...............................................................9
DIRECT CALCULATION USING BEAM
ANALYSIS ............................................. ................... 9
Gcncral ............................. .. .......................................... 9
Modelling of geometry .......... .... .................................. 9
Boundary conditions .................. ................................ 10
Loading conditions ......................................... ........... 10
Results .............................. ............................... ........... 10
FORMULA BASED ANALYSIS, BASIC
FORMULAE ........................................................... 10
Rigid c;ontainer securing arrangements
(Ce ll guidc.~ and similar) ............................................. 10
Non-rigid securing arrangements (Lashings and
sin1ilar) ....................................................................... 10
Container stack with four flexible horizontal
supports .... ..................................................................11
Container stack with combined rigid and flexile
horizontal supports ............. ........ .......... ...................... 12
6.5
7.
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7 .9
8.
8. 1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
Container blocks ................. ....................................... ·12
FORMULA BASED ANALYSIS, DERIVE D
FORMULAE ........................................................... 13
General ...................................................................... 13
Container stack with single rigid support .................. 14
Container stack with two rigid horizontal supports .. J4
Container slack with three rigid horizuntal
supports ..................................................................... 15
Container stack with single tlex ibl e support ............. 15
Container stack with one rigid and one flexible
support ............ .............................. ............................. 16
Container stack with two flexible horizontal
supports ......................................................... .. .......... 16
Container stack with one rigid and two flexible
horizontal supports .................................................... 16
Container stack with three flexible horizontal
supports ..................................................................... 17
SPECIAL CONTA INER ARRANGEM.ENTS .... 17
General ...................................................................... 17
Mixed stowage (20' container in 40' cellguide) ....... 17
40' container in 45' cellguides ........ .......................... 18
Effectiveness of lashings aLtached to lashing
bridge ................. .. .. ....................................... ............. 18
Vertical lashings - Wind lashing .............................. 18
Block stowage in hold without cellguides................. 18
Platfonn based containers with reduced stiffness ..... 19
Containers placed on 2 hatches or on hatches
and side pillars .................................. ......................... 19
APPENDIX A
APPROVAL OF L ASHING
COMPUTERS/SOFTWARE ............................................ 20
APPENDIX B
CALCULATED EXAMPLES .......................................... 22
DET NORST<'E VERITAS
4
August 2003
1. General
Ch.2
Design loads
1.1 Introduction
I."J.1
Ch.3
Loading conditions
For Ships intended for container transport the "Rules for Classification of Ships" require that app roved securing arrangements for the cargo containers are fitted.
1.1.2
The purpose of this pu blicalion is to serve as an aid to those .responsible for the planning and strength evaluation of securing
arrangements for cargo containers on board ships. Acceptable
assumptions and cak:ulation procedures supplementing the
general requirements stated in the Rules for Classification of
Ships are given.
Ch.5
Direct calculation
using beam analysis
1.1.3
Ch.6& 7
Formula based
analysis
Ch.8
Special container
arrangements
Ch.4
Principles of analysis have been outlined for normal types of
securing arrangements, including cellular containment structures (rigid containment system).
1.1.4
For securing arrangements ba."ed on lashings or similar, calculation formulae taking into account the interaction of containers and supports have also been included.
1.2 Procedure
This classification note describes methods for performing calculations of container securing arrangements. The calculations
are based on requirements given in Rules for Cla.~sification of
Ships.
Two different calculation methods are desctibcd "Direct calculation using beam analysis" and a "Formula based analysis"
these two methods are in general considered to be equivalent.
Should the re however be discrepancies in the results of the two
methods the direct calculation method will be decisive (This is
also the method used in approval).
The flow chart in Figurel- 1 gives an overview of applicable
chapters depending on the meth()d of calculation.
The chapters are brietly described in the following:
Ch.2. Design Loads, gives description or reference to the applicable local loads, like wind loads and accelerations.
Ch. 3. Lnading Conditions, gives a description of the app 1icable
loading conditions.
Ch.4. Acceptance criteria, gives applicable strength ratings for
the containers and m·commendations for the lashing equipment.
Ch.5. Direct calculation usin!J beam analysis, outlines the procedure for calculation of container arrangements where the
containers and lashings are modeled as beam elements.
Ch.6. Fo rmula based analysis, Basic formu lae, outlines the basic formulae for the simp 1ified calculalion of ordinary container arrangements.
Ch.7. Formula based analysis, Derived formulae, gives derived formulae (from the Basic formulae described in Ch.6) for
simplified calculation of ordinary container arrangement'\.
Acceptance criteria
fig ure 1-1
Flowchart
1.3 Definitions
1.3.1
References to directions refer to the principal axis system of
the ship. Thus the terms vertical, horiwntal, longitudinal and
transverse when used refer Lo the ship's axis.
1.3.2
With regard to terms used in this note reference is made to
Rules for Classification of Ships Pt.5 Ch.2 Sec.6.
1.3.3
The following symbols have been used:
=
=
a, =
g
=
Pw =
k,. =
GM =
¢ =
M =
b~ =
h
=
nb =
n
=
i
=
av
al
Kc =
KI =
Ph
=
a
=
P1i =
Pri
=
Ch.8. Special container arrangements, describes calculation
methods for special container arrangements which are not necessarily covered by the other methods e.g. 20' containers in 40'
cell guides.
Psh =
Appendix A Approval of lashing computer/software, gives
guidance to procedure for type approval of computer software
fo r determination of forces in lashi ng systems.
a
Appendix B. Calculated examples, gives some calculalcd ex amples for easy reference.
Pch =
=
=
combined vertical accelernlion *
combined transverse acceleration *
combined longitudinal acceleration *
acceleration of gravity = 9.81 mfs2
wind load according to Pt.5 Ch.2 Sec.6 G
radius of gyration*
metacentric height*
roll angle*
mass of container (M3 for variable container masses)
distance between bottom supports of container in mm
height of container in mm
number of interconnected stacks in container bluck
number of tiers in stack or block
number of tiers of containers in stack or block below
the level in question (also valid for j, k and m)
racking stiffness in kN/mm of container wall
horizontal stiffness in kN/mm of container lashing
connected to level i
horizontal force in kN acting per half container (Pha for
variable forces)
denominator of container in stack (from l ton)
lashing force in kN of lasing connected to level i, similar for k, j and m
horizontal support force in kN actin at level i, similar
for k,j and m
vertical support force in kN acting at bottom of container stack due to horizontal loads
vertical support forces in kN acting in side posts of
lower most container of stack due to horizontal loads
Psh - Phi h / 2 bs
assumed fraction of hori~ontal load acting on container
end, which is transmitted through the container wall.
Normally a may be taken as 0.5 and 0.0 for end and
side walls respectively
DET NORSKE VERlTAS
5
August2003
qc
= clearance in mm of rigid transverse support at level i,
similar at levels j, k and rn
t>io = calculated horizontal displacement in rnm at level i of
a horizontalunsupported stack of containers when sub-
q.i
-----
jected to a uniform horizontal load, similar ar levels j,
kand m
= calculated horizontal displacement in mm at level i of
a stack of containers when subjected to a horizontal
point load at level j, similar for other combinations of
displacement and point load levels.
*For details see P t3 Ch.l Sec.4 B
1.4 Assumptions
1.4.1
Ship huU supports are normally assumed rigid. In special cases
(e.g. shoring forces at ship sides) it may be necessary to consider non-rigid supports. Sec also Ch. 8.
Wind exposed
container
Figurc2·1
1.4.2
Calculutions are assuming that contuincrs have at least normal
strength and stiffness, i.e. closed boxes, open-top boxes, tank
containers. For platform-based containers see Ch.8.
1.4.3
All containers in a stack or block arc placed in the same direc-
tions, i.e. all containers with doors or doorJess ends in same direction.
1.4.4
Friction effects are not taken into account.
Wiudlvad.
2.3 Accelerations
2.3.l
Accelerations should be computed according to Pt.3 Ch. l
Sec.4 B, i.e. extreme dynamic loads arc to be used. The transverse dynamic acceleration is not to be taken less than the minimum acceleration given in Pt.5 Ch.2 Sec.6 0301.
The actual/realistic roll radius of gyration, kr, and metacentric
height, GM, may be used in the calculations instead of the rules
defined provided these have been computed for the actual condition.
1.4.S
Pretension of lashings is noL considered.
Nvte:
2.1 General
The rules defined rolling angle is given in Pt.3 Ch. 1 Sec.4. lf rolling angles is specified in exce&~ of these rules defi ned the acceleration~ in general should be computed in accordance with Pt.3
Ch.I Sec.4 B utilising the specified roll angle and the iulcs de-
2.1.1
fined period of roll. This will lead to very high accelerations un less the period of roll is increased.
2. Design Loads
Design loads applied in direct calculations arc to be taken as
given in the Rules for Classification of Ships Pt.5 Ch.2 Sec.6
G. Wind loads and accelerations arc further specified in 2.22.3 in the following.
---e-n-d···Ol~--N-O·t·C···
2.2 Wind load
3. Loading conditions
2.2.1
For wind-exposed stacks or containers a wind load of l .171
kN/m2 is to be applied to the side and end walls. Giving the following values for standard ISO container walls, in accordance
with Pt.5 Ch.2 Sec.6 G:
3.1 General
Sides 20' long, 8.5' high
Sides 40' long, 8.5' high
Ends, 8.5' high
Pw = 18.5 kN
Pw= 37 kN
Pw =7.5 kN
3.1.1
In Table 3-1, applicable loading conditions are listed with indications regarding their applicahility. In the subsequent chapters the relevant loading conditions will be described in more
detail.
Table 3-1 Load case overview
Ve1ti<.:al
LC Description
Transverse loading I
L
l!
Vertical loading
g + llu
2
3
4
Transverse loading II
Longitudinal loading
Horizontal
Wind
a.
Ye.<:
.
No
e: cos(¢)
a,
~
a,
Yes
Yes
3.2 LCt: Transverse loading I
3.2.l
For deck stowage extreme transverse accelerations are combined with the acceleration of gravity acting downwards.
Wind loads shall be added to wind exposed containers.
See also Figure 3-1.
DET NORSKE VERlTAS
6
August 2003
3.2.2
3.5 LC4: Longitudinal loading
For hold stowage extreme transverse accelerations arc combined with the acceleration of gravity acting downwards.
3.5.l
Por deck stowage extreme longitudinal accelerations are combined with the acceleration of gravity acting downwards.
Wind loads shall be added to wind exposed containers .
See also Figure 3-4 .
.----t-• M a,
3.5.2
ror hold stowage extreme longitudinal accelerations are combined with the acceleration of gravity acting downwards.
Mg
Figure 3-1
Load case 1
M
3.3 LC2: Vertical loading
3.3.1
1:or deck slOwagc extreme vertical accelerations are com bined
with the acceleration of gravity acting downwards.
Sec also Figure 3-2.
3.3.2
For hold stowage extreme vertical accelerations are combined
with the acceleration of gravity acting downwards.
See also Pigure 3-2.
Figure 3-4
Lo11d case4
4. Acceptance criteria
4.1 General
M
4.1 .l
Acceptance criteria for the container box, lashing equipment
and the ship structure is outlined in Pt.5 Ch.2 Scc.6 I. fn the following chapters strength ratings for ISO-containers and guidance as to the allowable forces io the securing equipment ar.e
given .
M (a,.+g)
Figure3-2
Load ca~e 2
4.2 Container box
3.4 LC3: Transverse loading II
3.4.1
For deck slOwage extreme transverse accelerations arc combined with the vertical component of acceleration of gravity
acting downwards.
Wind loads shall be added to wind exposed containers.
3 .4.2
Fo.r hold sto wage extreme transverse accelerations arc combined with the vertical component of acceleration of gravity
acting downwa rds.
f•'i i.<ure 3-3
Load C.'lSC 3
Mg
4.2.1
Container strength limits are no1mally to be in accordance with
the required mini mum (tested) strength values an d capabilities
given .in ISO-standard 1496/ I. Allowable forces strength ratings are given in Table 4- 1.
1'c1ble 4·1 Strcnglh ratings
Standard ISO
20'
150
150
75 (150>!<)
40'
Rru;king force door end
150
Racking force doorlcss end
150
Racking force side walls
75 ( 150*)
Corner post compression
864
864
Vertical tension in top comer
250
250
(from locking device)
Vertical tension in bottom cor250
250
ner (from locking device)
I.ashing loads in comer casting (in plane of cont. wall)
150
150
Horizontal
Vertical
300
300
Horizontal shoring forces on comers (perp. lO cont. wall)
Lower comer, tension
200
250
Lower comer, compression
300
350
Upper comer, tension
200
250
Uoocr corner, compression
200
250
~ For closed box container:;
DET NORSKE VERTTAS
7
August 2003
l S0/150 kN
•
2501250 kN
~5(150)kN
2001250 kN
2501250 kN
Figure 4-1
Strength ratings 20' I 40'
4.3 Container securing equipment
4.3.1
Working loads in container securing devices are in general not
to e xceed 50% of the minimum breaking load of considered
equipment.
Table 4-2 shows guidance values of maximum securing loads
for selected types of the container securing devices, for calculation purposes values for actual equipment is lo be utilised.
DET NORSKE VERlTAS
8
Classifica1ion Notes - No. 32.2
August 2003
Table 4-2 Guidance values for lashing equipm ent
Item
Type
Typical MSL [kN} l >
Figure
Lashings
1
Lashing rod
2
Turnbuckle
-o
_,_
-ri=-I
-~
3
Penguin Hook
4
D-Ring
5
Lashing plate
-230
_Q_
/
_ID_
Twist kx:ks and deck connections
6
Twist lock (single)
7
Twist lock (linked)
8
Flush ISO socket
9
Pedestal ISO socket
lO
Oove tail so1:kel with twist lock
_+-
-+=t t=
-er
250
2102)
250
25{)
:rb:
IJ.:r.
210
...
.....- __
I
•
210
250
210
I
In hold stowage and block stowage
11
Stacker (single)
12
Stacker (double)
13
Linkage plate
14
Pressure element
15
T/P element
-+--
•=
-c:w:::J-
==.
=I
=I
Ii -.
•• =
•
I
I
These values are selected to match the ~trength rating of the containers, for light stack weight.~ &mailer values may be accepted.
As item 6 + Horizontal tension a_q given
3)
As item l 1 + Horizontal tension us given
lJET NORSKB YERITAS
2103)
210
650
650/550
t ::::::
2)
J)
210
9
Augus12003
4.4 Ship structure
When a force F (3.85 kN for the door end and 10 k.N for the
door-less end) is applied to the container the calculated deflection should be l mm.
4.4.1
The supporting structure for the containers such as hatch covers. decks, inner bottom and bulkheads must be evaluated according to Pt.5 Ch.2 Sec.6. accep1ance criteria is given in T300.
5.2.2
5. Direct calculation using beam analysis
The twistlocks must be modelled with a hinge at one end to
avoid transferring bending moments between the containers.
see Figure 5-2.
Twistlocks are to he modelled with an area sufficiently large to
avoid large tensile deformations.
5.1 General
5.1.1
This chupler gives guidance on how to perform beam analysis
for container lashing arrangement<>. See also Appendix B for
examples.
Hi11ge
...-Twist lock
5.1.2
The pro<.:edure described below represents the method used by
the program NAUT1CUS Container Securing.
ft'igure 5-2
Hinge at end of twist lock
5.1.3
The container stacks are modelled as two independent 2-dimensional beam models, one ror the door end and one for the
doorless end to incorporate lhe different racking stiffness.
Each stack may be analysed separately unless there are connections between the stacks such as double stackers or similar,
in which case the whole block needs to be analysed. Non-structural top bridge fittings arc ignored in the analysis.
5.1.4
Non-linearities such as compression elements and gaps in horizontal supports mus1 be included. The analysis is to include
tbe effects of clearances. For individual coniainer stacks, clearances of stack fittings may be ignored. Stipulated clearances
between container stacks and horizontal supports are to be taken into account. For container blocks with horizontal supports,
clearances of bridge fittings within the block are to be taken
into account. Non-linearities such as compression elements
and gaps in horizontal supports must be included.
5.2.3
Stacking cones are modelled as twist locks with the difference
thut these must be modelled as non-linear clements capable of
taking compresllion and shear but not tension.
5.2.4
Double stackers, linked twistlocks and linkage plates are modelled with the actual cross sectional area. The transverse elements should he positioned nl the midpoint of the twistlock/
stacking cone and in general be fitted with hinges at both ends,
sec Figure 5-3. For components that have the capability to
transfer vertical shear rorces these hinges may be omitted.
Gaps in the bridges must be modelled as non-linearities.
Link
Hinge
'~
---~
5.2 Modelling of geometry
II
Hin~c
'Linking elements
5.2.1
The analysis is to take into account the flexibility or the containers. Unless otherwise specified, the rn<.:king stiffness Kc of
container end walls for normal closed box ISO containers may
be taken as:
Figure 5.3
Linking elemeuts and double stackcrs
Kc = 10 kN/mm for doorlcss ends
5.2.S
Kc
= 3.85 kN/rnm for door ends
Unlc.~s otherwise specified, the racking stiffness of container
sidewalls may be taken equal to doorless container end walls.
The corner posts arc modelled with a shear area so that the correct racking stiffness is obtained, according to Figure 5- 1. The
bending stiffness o f the beams should be high to avoid introducing bending strc..~ses in the elements.
c--_.,~
....._._________,
,'
I
'
''
.
'
I
''
r
I
'
Figure 5-1
Racking .stiffness of container
'
''
I
r
r
Buttress supports, compression and tension clements arc modelled with the actual cross sectional area. Pure compression elements must be modelled as non-linear element taking
compression only, in addition the gap between the clement and
the supporting structure must be modelled as non-linearity.
Hull deformations, if significant, arc to be taken into account
when detc1mining the shoring for<.:cs.
5.2.6
Por ordinary lashing units with one turnbuckle or lashing, the
lashing should be modelled as beam clements with characteristics according co Table 5- 1. The lashings elements shall be
l'itted with hinges at both ends to avoid transfer of bending moments.
r
''
I
I
''
r
Table 5-l Lashing characteristics
IArea
-, Modulus of elasticity f N!mm2 j
Rod lashing I Actual area or rnd I 40 (l -1000) maximum 2.06 x 1o5
l = The length of lashing includinu turnbuckle, in mm
For wind lashings please sec Ch. 8.4.
DET NORSKE VERITAS
10
August 2003
5.3 Boundary conditions
6.1.5
5.3.1
Hull deformations, if significant, are to be taken into account
when determining the shoring forces.
Elements attached to the ship structure should be restricted
from translation.
5.4 Loading conditions
5.4.1
Lc:J.ding condition:; arc to be iu acCOi\li\nc~ w·itli Chaptl;1 2 cl.HU
3.
6.2 Non-rigid securing arrangements (Lashings and
similar)
6.2.1
For non-rigid securing arrangements the vertical support forces. internal forces of the container stacks. horizontal suooort
forces and lashing forces are all to he calculated if relevant.
6.2.2
5.4.2
Loads should be applied as point loa<ls in the corners of the
containers. The distribution of transverse inertia forces between the top and bottom corners should be taken in relation to
the centre of gravity of the container, which should in no case
be set lower than 45% of the container height. Vertical inertia
forces are only applied to Lhc bottom comers of the container.
W in<l loads may be equally distributed between the 4 comers
of the container, on the windward side or distributed on all corners of the container.
The analysis is to take into account Lhc flexibility of the con tainers. Unless otherwise spedficd, the racking sliffness Kc of
container end walls for normal closed box ISO containers may
he taken as:
Kc = 10 kN/mm for doorless ends
Kc = 3.85 kN/mm for door ends
Unless otherwise specified, the racking stiffness of container
sidewalls may be taken c.qual to doorless container end walls.
6.2.3
5.5 Results
5.5.1
Forces shall be extracted from the model to continn thut the
loads in the securing devices between the containers and the
container boxes themselves are not to exceeding the safe working load of the securing devices or the container strength timit,
according to Chapter 4.
Tn addition the reaction forces in the ship structure must be
considered.
Calculalions are to be performed for container stacks or blocks
assuming both doorless and Joor end walls. Normally maximum vertical and horizontal reaction forces at the stack base
are found for doorles.~ ands, whilst maximum horizontal support forces and lashing forces are found for door ends.
6.2.4
The analysis is to be based on the e lastic stiffness of lashings
according to their type and dimensions, ref. Ch. 7. I . I.
6.2.5
6. Formula based analysis, Basic formulae
6.1 Rigid container securing arrangements
(Cellguides and similar)
6.1.1
The maximum vc11ical support force from corner base fitting
may be taken as:
P~ = 0.25
II
r Ma(.~ +av)
kN
11=!
The analysis is to include the effects of clearances. For individual container stacks, clearances of stack fittings may be ignored. Stipulated clearances between container stacks and
horizontal supports are to be taken into account. For container
blocks with horizontal supports, clearances of bridge fittings
within the block arc to be taken into account as outlined in Ch
6.5.
6.2.6
The effects of vertical connections between the containers of a
stack are to be taken properly into account. The effects of possible tipping of container stacks without lock connection at
bottom supports are of special importance and must he especially considered ref. Ch. 5.2.
6.2.7
6.1.2
The maximum compressive force in container end posts may
be taken as:
n
Ps = 0.25 'LM 11 (g+a 11 )
kN
The calculations are based on methods of analysis applicable
for structures in general. In the analysis the container walls
may be considered as shear panels. The interaction between
the two ends (or sides) of containers may normal I y be assumed
negligible, see also Ch. 8.2.
6.2.8
a=2
Generally, the horizontal force of the container per end or side
is to he taken as:
6.1.3
The stresses and forces in the securing structures for hori:Lontul
accelerations and forces from wind, where relevant, arc to he
calculated for transverse and longitudinal forces per contuiner
equal (M <ti+ P w) and (M a1 + Pw) k.N, respectively.
6.1.4
The analysis required for rigid container securing arrangements depends on the Climplexity of U1c arrangement. For
complex cellular securing structures, direct analysis may be
necessary. In other cases manual calculation will be s ufficient.
ah = at or a 1 for transverse or longitudinal accelerations, res pectively.
6.2.9
M aximum vertical s upport forces, racking forces, horizontal
support forces and lashing forces may normally be delem1ined
directly in accordance with Ch. 7.
DF.T NORS.Kb VERITAS
11
August 2003
6.2.10
container posts is normally determined as the larger of:
The combined maximum vertical support forces may be determined as the larger of:
On compression side (positive):
kN
a=2
and
n
P~,. = 0.25
n
Pc =0.25L,M0(.1:+av)
L M aR +Psh + L Psi
kN
a=l
n
or
kN
LM u8 +Pch +I.Psi
Pc= 0.25
a=2
= cakulated compressive force in post due to horizontal
Pch
Psc=0.25 fM a~ + av)
loads
kN
a=l
LPst = as given in Ch. 6.2.10
6.2.12
The racking force in the wall of the lowermost container stack
is determined hy:
On tension side (negative):
n
Pst =0.25 L,M 0 gcos¢ - Psh + L.Prl
kN
n
a=l
S,
= LPha +aPh1 -
kN
L;P,
a=2
If Pst becomes negative tipping will take place and locking
cones or twistlocks arc to be installed (see also Rules for Classification of Ships Pt.5 Ch.2 Sec.6 F302, for stacks without
lashing or shoring).
P~h
= calculated
vertical support force due to horizontal
loads as given in Ch.7.2.3
:tP~1 = sum of the vertical components of relevant lashing
forces according to Ch.7
On compression side :tP51 is only added when internal
cross lashing is used
On tension side LP sl is only added when external lashing is used
6.2.ll
The combined maxi.mum compressive force in the lowermost
-
LPr == sum of horizontal lashing or supporting forces (Pri• Prj
etc.) calculated in accordance with Ch.7.
P111
horizontal force at end of lowermost container
=
In cases where there arc two or more containers above the upper lashing or fixed support, the racking force in the lower of
these should also be checked.
6.3 Container stack with four flexible horizontal
supports
6.3.1
Consider a container stack supported by lashings at levels i, j,
k and m in that order from the bottom.
For the analysis in the following, reference is made to Figure
6-1.
Omm
\
I
I
'
' '
:
I
I
\
t
t
I
I
Omo
: \: l 011
~
\, :
\
I \
I \
1 \
t
\
\
,1
t
•'
\
\
•
\:
-·
I
•
I
Ip
•'
Ujj
I
I\
\I \
)
I
'
\
\
\
I
I
I
Uu
\
\
\ \
\ \
\ \
'
I
I
\
r
\
\\\'
' ,, \
\
\
I
,,,,
\
\
I
\
,,,,,,
,.,
\
\
.
'41
t
D.ET NORSKE VERITAS
~
I
~:
I
I
' .h1... •
I
', \
I
I
S:
I
\
'
Fibrure 6-1
Four flexible supports, general case
Ujo
I
f
r
\
•' \ \ s:. ..
n=6
f
I
I
I
-
I
.M... '
I
~
:\ I \
I \:
I
\
:
,___ _ _ _ _ ___ _ .JI
•'
...
'
P115
I
I
I
\i
,
\
I
'
I
'
S:
Ujo
I
I
t
12
August2003
6.3.2
with two lashings, the system reduces to:
Disregarding the lashings, the free horizontal displacement at
level i is given by;
Oio
=-.1- ( a Li Pha + Li
Kc
a =l
n
L,Phb
)
a=lb=a+1
and similar for other levels j, k and m.
6.4 Comainer stack with combined rigid and fiextle
horizontal supports
6.3.3
The horizontal displacement at level i due to a horizontal force
acting at the same level is given by:
i. p.
8-· =--!
K
u
c
6.4.1
Consider a stack of containers as in 2.3. Let one suppor:t be rigid, for example at level j. A clearance Ojc at that support is assumed.
6.4.2
The displacement at levels below the force in question is proportional to Lhe level number, e.g. the clisplacement at level i
due to force acting at level k is given by:
The displacement at levels above the force in question is equal
to the displacement at the force level.
6.3.4
The support force at level i is expressed as a function of the .resulting horizontal displacement at the same level, i.e.:
The support forces at level i, k and m are gi vcn by the formulae
in 6.3.4. At level j the resulting displacement is given by:
Consequenlly the linear equations in 6.3.5 are modified as follows:
- The diagonal clement
[
~: + j) ~ j
- The displacement
6.4.3
In this way the linear equations may be set up for an arbitrary
combination of rigid and flexible supports.
6.3.5
The horizontal forces as mentioned in 6.3.3 must be equal to
the corresponding support forces given in 2.3.4. Consequently
the following linear equations may be derived, on matrix form:
(~+m)
Km
k
.i
k
(~:+k)
j
j
(K
- c+J')
Kj
j
P~l
Prk _
Pr; Pr;
[v,
OkoKc
8j 0 K,.
oio Kc
(~; +i)
For example, with four rigid supports the horizontal support
forces are given by:
m k
J
Pmi
(Om.o - Omc)Kc
k
k
J
Prk
(Oko - OkrJKc
j
j
j
PrJ
(Ojo -Ojc)Kc
Pri
(Oio - Oic )Kc
i
i
i
6.5 Container blocks
6.5.1
From these equations the horizontal support forces Prnv Prk • Prj
and Pri may be solved. If the number of las hings is less than
four, the system reduces corresponclingly. E.g. for a system
Container stacks conne(;ted by horizontal bridge stackers may
he regarded as a block with respect to lashing und rigid horizontal supports. It is assumed that bridge stackers are fitted at
each level of horizontal support and that the clearances at
stackers normally are negligible. T he block may be calculated
on the basis of an analysis of single stacks with the same deflection (fixed suppo1t clearance). The resulting horizontal
support force will be the sum of all support forces from the individual stacks.
If the horizonial stackcrs are fitted with a clearance &b at each
stacker, the suppon clearances &ic• &jc• &kc or &1c are for each
stack away from the rig id support LO be increased by &b. Arrangement with a single rigid support is shown in Figure 6-2 .
DET NORSKE VERlTAS
13
August2003
- - - - - - - - - - - - -
..
n=6
i:::5
'
'
l---~1----~.-----1 •~
l
Pn
.' ..
.:' :.'
.. ..
:'
:
t
:
o
I
.: ::
1---~ ~--~1----1
..
•
•
.....
'.
I
:
I
''
..
1---~~--~1----1 / ,'
.,
,,,,
Figure 6-2
Bloc.k with single rigid horizontal i;upport
6.5.2
If the number of stacks in a block i.<:> greater than 4 and bridge
stackcrs are fitted at all levels in the block, a reduction in the
hori:t.ontal support forces may be introduced due to the stackers
giving a certain vertical shear restraint. The final support forces may be found a1>:
Pri
= calculated horizontaJ reaction force for block
= reduction factor as given in Table 6-1
1~~ I!-4 l~.98 l~.95 l~.91 I~.85 16.79
7.1.2
The calculation fonnulae have been ba~cd on the follow.ing assumptions:
Prif = Cr. Pri
Cr
general, the formulae may be applied for the determination of
vertical suppo11 forces, horizontal support forces and .lashing
forces. Note that the formulae for vertical support forces do not
include the vertical component of possible lashing forces and
vertical mass forces.
1>10
~.75
The racking force Sr in the end wall of the lowermost container
is to be calculated according to 6.2.12 with the reduced Prif inserted in the fonnula. The vertical support forces may be calculated with the uncorrected P n-
6.5.3
Tn order to reduce the hori:t.ontal support forces at rigid block
supports, the supports may be arranged for absorbing both
compressjon and tension. ff the clearances at tbe individual
stackers are considered to be negligible, a 50% distribution between the compression and tension side may no1mally he used
when calculating the support forces according to 6.5.1 and
6.5.2.
In case of clearance at each horiwntal bridge stacker, redistribution towards 100% compression will take p lace. A 50% distribution may be achieved hy omitting all bridge stackers
between middle stacks, thus obtaining two individual blocks.
The bending stiffness of the container wall is assumed >>
than their shear stiffness. The container walls have therefore been considered as shear panels.
Internal clearances in stacking and locking members of individual stacks are ignored.
Tensile vertical forces are assumed taken by lock stackers.
If lock slackers are not fitted and containers may be subject to tilling, the lashing forces will have to be specially
considered
The flexi'bility of container walls and lashings are assumed
to be linear.
Pre-stressing of lashings is not included in the consideration.
Containers subjected to horizontal acceleration forces are
assumed homogeneously loaded with gravity centre in the
centre point of the container (However a CoG of 45% may
be utilised).
7.1.3
The horiwntal spring stiffness of simple lashing devices supporting the container stack at level i may be expressed as:
or
7. Formula based analysis, Derived formu~
lae
7.1 General
E1 = modulus of elasticity of lashing in kN/mm2.
7.1.1
For ordinary lashing units with one turnbuckle or locking tensioner nominal E 1 values may be:
The following describes elementary formulae for the analysis
of stacks of containers when subjected to horizontal forces. In
Chain la~hing: 100 kN/mm2
Wire lashjng: 75 kN/mm2
DET NORSKE VEJUTAS
14
August 2003
Rod lashing: See Table 5-1
At
= cross sectional area of lashing in mm2, to be taken as:
by :
Wire lashing: Nominal area
(a=lf (a - 0. 5)Pha - iPri )1i
Chain lashing: Area of one side of link
s1
hl
t1
=
Rod lashing: Actual area of rod
length in mm, see figure 7-1
length in mm, see Figure 7-1
length in nun, see Figure 7-1
Psh= - - - - - - - - - - -
~
~-:
'J-lor wire lashing EzAt may be substituted by a stiffness constant C. Unless otherwise specified C may be taken as:
C
= 8000 kN for 12.5 mm diameter sceel wire rope
= 15000 kN for 16 mm diameter steel wire rope
= 2 1000 kN for 19 mm diameter steel wire rope
= 28000 kN for 22 mm diameter steel wire rope
= 38000 kN for 25.4 mm diameter steel wii'e rope.
-
For intennc<liate diameters C may be de tcm1ined by linear interpo Iation.
\
'
\
I
I
'
i=3
., "
-
'
I
I
f
I
I
I
I
I
'
'
I
I
I
I
I
f
I
I
f
'
't
I
I
I
I
I
I
I
I
I
I
I
I
'
I
I
I
I
I
I
'
I
I
-
I
I
I
I
, ,,
' ,'
''
.,''
,,,,
•
I
I
f
I
I
I
I
..
h1
I
I
'
'
'
''
I
-
For lashing dcvicelJ consisting of different elements the spring
stiffness may have to be determined experimentally.
;
I
kN
b.1,
~
""
'1. ~
I
Figure 7-2
Single rigid horizontal support
I
I
I
7 .3 Container stack with two rigid horizontal supports
Figure 7-1
Stiffness of simple lashing
7.2 Container stack with single rigid support
7.2.1
The arrangement is shown in F igure 7-2.
7.3.1
The ammgemen t is shown in Figure 7-3.
The c learances at the lower and higher supports, Oic and ~c respectively arc assumed to be known. The unsupportea dis placement'>, Oio and 8jo may be calculated in accordance wit11
the formulae i n 6.3.2.
The clearance at the rigid support, oic• is assumed to be known.
The unsupported displacement, Sio• may he calculated with the
formula 6.3.2.
7.3.2
7.2.2
T he horizontal support force derived from the general formulae in 6.4.3 is given by:
At level i:
The horiwntal support forces derived from the general formulae in 6.4.3 arc g iven by:
kN
kN
At levelj:
Not valid for Oic > Oio·
kN
7.2.3
The vertical .s upport force due to the hori7.ontal forces is given
DET N ORS KE VERITAS
15
August 2003
Jf any of the support forces becomes negative, this support will
not he engaged. The calculation has to be repeated with the remaining support only, accorcling to 7.2.
At levelj :
7.3.3
The vertical support force is given by:
At level k:
[ L(a -0.S)Pha -(iPri + jP )lhJ
rj
Psh -_
kN
a=I
hs
If any of the support forces becomes negative, this support will
nol be engaged. The calculation has lo be repeated with the remaining support~, according to 7.3.
7.4.3
The vertical support forces are given by:
-
-
7.5 Container stack with single flexible support
81
-
7.5.1
The arrangement is shown in Figure 7-4.
The horizontal spring stiffness of the lashing, Ki, may be calculated in accordance with the formu la in 7 .1.3.
The unsupported displacement, Oio• may be calculated in accordance with the formula in 6.3.2.
7.5.2
I
I
'
I
I
'
f
I
I
I
I
I
'
The horizontal support force derived from the general formulae in 6.3.5 is given by:
I
I
I
I
I
I
I
I
I I
1/
,,,,
~
7.5.3
The vertical support forces may be calculated as given in 7 .2.3.
Figure7-3
Two rigid horizontal supports
-
7 .4 Container stack with three rigid horizontal supports
I
I
-
-
6.3.2.
7.4.2
The horizontal support forces derived from the general formulae in 6.4.3 are given by:
AL level i:
I
I
I
I
I
I
I
aij
:
I
K·
kN
Figure 7-4
Single flexible horizontal support
DET NORSKE VERJT AS
''
..
-
7.4.1
T he clearances at the three supports, Sic• O·c and dkc are assumed to be known. The unsupported displacements, Bio• Ojo
and Oko may be calculated in accordance with the formulae m
'
'
''
' t'
I
. '.
'
I
I
I
I
I
I
I
I
' '
I
I
I
I
'
I
I
I
I
I
I
I
I
I
I
I
JI
I
I
I
,,
I
"
II
'
I
I
16
August 2003
7.6 Container stack with one rigid and one flexible
support
7.6.1
The hoti:tontal spring stiffness of the lashing, Ki• may be cal culated in accordance with the formula in 7.1.3.
The clearance at the rigid supp01t, oic, is assumed to be known.
The unsupported displacements, 010 and ~\o may be calculated
in accordance with i.he fuuu uh1~ i 11 Ci.3.2.
The horizontal spring stiffness of the lashing, Ki and Xj may be
calculated in accordance with the formula in 7.1.3.
The unsupported displacements, oio and 8;0 may be calculated
in accordance with the formulae in 6.3.2. ·
7.7.2
The horizontal support forces derived from the general formulae in 6.3.5 are given by:
At level i:
7.6.2
The horiwntal support forces derived from the general formulae in 6.3.5 and 6.4.3 are given by:
At level i:
kN
At level j:
At level j:
kN
kN
7.7.3
The vertical support force s may be calculated a:-; given in 7.3.3.
7.6.3
Ojo
The vertical support forces may be calculated as given in 7.3.3.
JH
fy:
'I
rJ '
I
I
-
I
I
I
'
I
I
I
I
B~
--
-
--
-
'
''
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
'
I
'.
'I
I
: P,;
:---I'
II
I
I
I
I
I
o;'
..''''
'''
I
I
.'' ..'''
'' .'
.
I
I
'
I
I
1-------1 :
I
I
oI
,'
I
I
,'
"
I
I'
'.
,,
""
..
I
I
Figure 7-6
I I
Two flexible horizontal supports
H
7.8 Container stack with one rigid and two flexible
horizontal supports
Figure 7-5
One rigid and one flexible support
7.8.1
7.7 Container stack with two flexible horizontal supports
7.7.1
I
--
'
I
I
K·
I
-
''
'
I
I
I
I
I
I
I
-
~--
-
--
--
I
The anangement is shown in Figure 7-7.
The horizontal spring stiffness of the lashing, Ki and K; may be
calculated in accordance with the formula in 7.1.3. ·
The clearance at the rigid support, okc• is assumed to be known.
The unsupported displacements, 9, Ojo and oko may be calculated in accordance with the formu lae in 6.3.2.
oi
DET NORS KE VERIT AS
Classitication Notes - No. 32.2
17
August 2003
7.8.2
T he horizontal support forces derived from the general formulae in 6.3.5 and 6.4.3 arc given by:
At level i:
C · = Kc+ j
J
K.
J
kN
At level j :
7.9.3
The vertical support forces due to horizontal loads and forces
may be calculated as given in 7 .4.3.
At level k:
Skc
-
C·= Kc+i
t
K;
Kc .
C · = - +1
J
K·
J
7.8.3
T he vertical support forces due to the horizontal loads and
forces may be calculated as given in 7.4.3.
7.9 Container stack with three flexible horizontal
supports
~
~
.- ~ .
'.
\
P rk :
.
\
\
\
I
I
I
I
I
'
I
I
I
I
I
o·J
7.9.1
T he horizontal spring stiffness of the lashing, Ki, Ki and Kk
may be calculated in accordance with the. formula in ·1. l. 3.
Figure 7-7
Container stack with one rigid and two flexible supports
The unsupported displacement<:, Sio• oj o and Oto may be calculated in accordance with the fonnulae in 6.3.2.
8. Special container arrangements
7.9.2
The horizontal support forces derived fro m the general formulae in 6.3.5 are given by:
At level i:
8.1 General
8.1.l
In this chapter some special cases of container arrangement are
presented with applicable analysis methods. The calculation
methods described in the previous chapters are not necessarily
applicable for these a.trangemcnts.
8.2 Mixed stowage (20' container in 40' cellguide)
8.2.1
At levelj:
20' containers may be carried in cell guides designed for 40'
containers provided that:
Cones fixed lo the tank top or similar arrangements are fitted at mid hold to restrict sliding of the bottom of the 20'
:stacks.
At le vel k:
p
rk
2
2
r, _cJ.)
= K ok0 'c.c
~ I J. -; )+o.JO~'· - jc.)+io·
I
10 v
c
2 2(
)
C;CjCk - j C; +i 2j-Cj-Ck
kN
The 20' containers to be topped by at least one tier of 40'
containers (full or empty) in order to achieve maximum
stack loads.
Securing devices (e.g. stacking cones) are to be provided
between each tier of the 20' containers and be.tween the
top 20' container and the 40' container.
DET N ORSKE VERITAS
18
August2003
The loads on the securing devices between the containers
and the container boxes themselves are nol lo exceed the
safe working load of the securing devices or the container
strength limit.
The 20' conlaincrs are to have steel walls and top, i.e. open
frame containers are not allowed.
8.2.2
The container weight of the 20' stacks is delcrmined by the
Ht~kiHg force li111il of the lowest container. The rransversc dynamic forces on each tier may be distributed with 35% to the
midhold end and 65% to the cell guide end.
The racking force of the lowest 20' container is dctennined by
summing the transverse forces of the 20' container ends above
the lowest container with one half of the transverse force of the
lowest container.
8.2.3
JJ the 20' stacks are nol topped by a 40', the transverse force
distribution is LO be taken as 45% to lhc midhold end and 55%
to the cell guide end. Stacks with more than 7 tiers without 40'
on lop will be specially eonsidered.
8.2.4
The deformation of the container stack should also be analysed, taking into account the clearances between the stacking
cones and the corner castings, to verify that the different stacks
will not come inlo contact. The analysis should be performed
in longitudinal and transverse dir<.-'Ction and a combination of
bolh.
8.3 40' container in 45' cellguides
8.4 Effectiveness of lashings attached to lashing
bridge
8.4.1
When lashing is attached to a lashing b1idge the relative movement of lhc hutch cover and the ship structure will give rise to
increased loads in the lashing. To account for this phenomenon
in the calculations the MSL of the lashing is in general to be
reduced according to Table 8-1.
Table 8-1 Red uction of MSL
20' container stack 1)
T.ength
Shon
umg
I.ashing 3)
lashing 2)
10%
0%
L< 270 m
270 < L <315
15%
0%
L> 315
20%
0%
40' container stack
Leng
Short
lashing 2)
lashing J)
15%
0%
0%
20%
25%
0%
2)
Assuming a lashing gap al mid hold otherw ise values as 40' should be
utilised
Lashing from la~hing hridge to rirst tier above
3)
Lashing from lashing bridge to second tier ~bove
I)
8.4.2
For specialised arrangemenls with extreme lashing angles or
unusually long distance between lashing bridge and container
is to be specially considered.
8.5 Vertical lashings - Wind lashing
8.5.1
Wind lashings eannot in general be included in the analysis but
must be considered as a separate item.
8.5.2
8.3.l
40' containers may he carried in cell guides designed for 45'
containers provided that:
Cones fixed to the tank lop or similar arrangements are fitted at mid hold lo resttict sliding of the bottom of the 40'
stacks.
Securing devices (e.g. slacking cones) are to be provided
between each tier of the 40' containers.
Maximum stack height is 7 tiers.
The loads on the securing devices b etween the containers
and the container boxes themsel vcs are not to exceed lhc
safe working load of the securing devices or the container
strength limil.
The containers arc lo have steel walls and top, i.e. open
frame containers are not allowed.
8.3.2
The container weighl of the 40' stacks is determined by the
racking force limit of the lowesl container. The transverse dynamic forces on each lier may be distributed with 50% to the
mid hold end and 50% to the cell guide end.
The racking force of Lhc lowest 40' conlaincr is determined by
smnming the tram;verse forces of the 40' container ends above
lhc Iowe.st container with one half of the transverse force of the
lowest comainer.
8.3.3
The deformation of the container stack should also be analysed, taking into account the clearances between the stacking
cones and the comer castings. to veti ry that the different stacks
will not come into contact The analysis should he performed
in longitudinal and transverse direction and a combination of
both.
Due to the clearances in the twistlocks lhe wind lashing will
carry the whole load until the deformations of the stack have
closed these clearances.
8.5.3
For wind lashings fitted with special lurnhuckles, in order to
have the same "clearance" of the lai:;hing as the lwistloeks, the
vertical tensile force may be assumed divided between the conlaincr corner post and the lashing. 1/3 in the lashing and 2/3 in
the corner post.
!-<or lashings without such a device the w hole force is assumed
taken by the lashing.
8.6 Block stowage in hold without cellguides
8.6.1
Care must be taken so that. the verlicul and sideways support
points of lhc containers is aligned with the. fo r this purpose, reinforced areas of the ship structure.
8.6.2
The eftects of slowing mixed container heights in the holds
must be specially considered taking into account the support
points in the transverse bulkhead und i:;ide structure.
8.6.3
The effects of hull deflections due to sea loading are to be taken inlo account when calculating transverse shoring forces.
This is especially important for vessels with long holds and
where the ship side deflections are large. If lhc hull deflections
are unknown a conservative assumption should be made.
8.6.4
C..1earances in securing equipment between the secuJing equipment and the supporting structure must be specified.
DET NO"RSKE YERlTAS
19
August2003
8.6.5
Container blocks in holds without transverse connections, only
compression pads (i.e. OSHA adaption) should be specially
considered since this equipment does not give any vertical
shear restraint and hence the horizontal support forces will be
increased.
8.7 Platform based containers with reduced stiffness
8.7.1
Platform based containers generally have reduced racking
stiffness and longitudinal strength that must be taken into account in the analysis.
8.8 Containers placed on 2 hatches or on hatches
and side pillars
8.8.1
ff containers are placed on 2 hatches or on hatches and side pil1ars the relative deformations must be accounted for in arrangement, by fitting overlong ISO sockets, or by including
this deformation in the lashing calculations
DET NORSKE VERITAS
20
August 2003
Appendix A
Approval of Lashing computers/software
A.1 Introduction
This is gu idancc to those who are involved in approval and cerLification of Lashing computers for a specific ship. T.e. the software manufacturer who wishes LO have his software approved
fnr :t c:peci fie- VPC:<:P]
hardware may be waived, but both nominated computers are
subject to cenification. ln addition, computers that are to be a
part of a ship's network should be approved in accordance with
other relevant requirements posed by the Society.
T he lashing computer is to be capable of producing printouts
of the results numerically. These numeric values are to be presented both as absolute values and as a percentage of the allowable values.
All screen and hardcopy output data arc to he presented in a
clear and uiio.ilibigu.vu;; iii.anncr w·ith idci·.tificativti of tlic vc, ..
Guidance is also given for those manufacture.<; that wishes to
have their software type approved.
sion number of the calculation program.
A.2 Definitions
In case two nominated computers are used, these are both to he
equipped with separate screen and printer.
Lashing computer system
A lashing computer system is a computer-based system for calculation and control of container securing arrangements for
compliance with the applicable strength requirements. The
lashing computer system consists of software (calculation program) and hardware (the computer on which it runs).
A.4 General hardware requirements
A.5 General software requirements
Lt. is recommended that the design and production of the calculation program is in accordance with appropriate quality standards.
Approval and certification for a specific v~ssel
The software is to present the relevant parameters of each con tainer arrangement. The following is to be presented:
Approval of software means that ONV approves the software
for a specific installation onboard a specific vessel. The approval is based on a review and acceptance of design, calculation method, verification of slorcd data and test calculation for
the specific vessel.
2) GM-value
Approval of the software is to be carried out for each specific
vessel where the software is to be installed.
Approval of the software results in approved rest conditions.
If the software is type-approved, the review and acceptance of
design is not necessary for each specific vessel. Only verification of user's manual, stored data and test calculations for the
specific vessel will then be carried out.
Certification (installation testing) is carried out to ensure that
the lashing computer system works properly onboard the specific vessel, and to ensure tl1al Lhc correct approved version of
the software has been installed.
Certification is to be carried out for each vessel where a lashing
computer system has been installed.
Type upproval
1) Draught
3) Each container weight
4) Position of each container stack
5) Lashing arrangement
6) forward visibility
7) Accelerations of each contitincr
8) Strength limi tation: Listing of obtained values compared
with the limit values according to Ch.4 (internal forces in
containers, forces in securing equipment and forces in supports).
9) A clear warning is to be given if any of the strength limitations are not complied will1.
10) The data is to be presented as screen and hard copy output
to lhe user in a clear and unambiguou~ manner.
The software is to r~jecl input errors by the user. For instance
negative weight input on containers or containers positioned
outside the ship is not to be accepted.
Type approvaJ means that DNV has approved the design methods and specifications of the software in general. The type approval is given based on a review and acceptance of design,
calculation methods and documented test results for at lea~t
two test vessels. Type approval certificate is issued.
The software and the stored characteristic data are to be protected against erroneous use. The software should be written to
ensme that these can not be altered by the user.
ln the type approval certificate it will he stated what kind of
calculations the type approval covers.
The software is to be user-friendly, with a graphic presentation
of the container arrangement.
In connection with approval for a specific vessel with type ap-
Any changes made to the software are to be made hy the manufacturer or h.is appointed representative. The Society is to be
informed immediately of any changes. Failure to advise of any
modifications to the software wilJ invalidate the certificates issued. In such cases the modified software is lo be re-assessed
in accordance with the approval and certification procedure.
proved !>Oftware, less documentation will be required, anti Jess
fee will be charged.
A.3 General requirements
The approval and certification process includes the following
procedures for each ship.
1)
Appmval of software which results in approved Test Conditions
2) Approval of computer hardware, where necessary
3) Certification of the installed lashing computer system
which results in a lashing computer certificate.
The approved test conditions arc to be kept onboard together
with the User's manual and the lashing computer Certificate.
The approved software is either installed on a type-approved
hardware, or it is to he installed on two nominated computers.
If two nominated computers are available, approval of the
A.6 Documentation to submit for approval
A .6.1 Hardware documentation
Requirements in Rules for C lassification of Ships Pt.4 Ch.9 are
to be complied with.
If the hardware is to be type approved, documentation according to Rules for Classification of Ships Pt.4 Ch.9 Sec. l is to be
submitted.
A.6.2 Software documentation
Approval of the test conditions is mainly based on comparing
the input and the results of the software calculations with values calculated by DNV. The difference is not lo be greater than
DET NORSKR VERITAS
21
August 2003
5% calculated according to the following:
((Value calculated by software)- (Value calculated by DNV))
I (Allowable)~ ±5%
The documentation must be prepared in a language understood
by the users. If this language is not English, a translation into
English is to be included.
All submitted documentation is to be identified with the following:
Name of vessel, name of yard, the yard building number
and the DNV identification numher of the ship for which
the program applies
2) Program name, version number and version date
3) Program manufacturer and address
4) List of contents.
I)
For each specific ship the following documentation is to be
submitted:
I) User's manual
2) Program description (not required for type approved software)
3) Test conditions
4) Stored characteristic data.
The user's manual is to contain:
I) A general description of the program denoting identification of the program and it's version number stated
2) Where applicable, a copy of the type approval certificate
3) Hardware specification needed to run the program
4) Listing of etTor messages and warnings with instructions
for actions to be taken by the user in each case
5) Listings of allowable strength limits with respect to the
container, lashing equipment and ship.
6) Exumple of calculation procedure supported by illustrations and sample computer output
7) Example of computer output of each screen display with
explanatory text.
4)
5)
6)
7)
8)
Deck stowage with twistlocks only
Case wilh exceeding stack weight
Case with exceeding lashing force
Case with exceeding lifting force
An example with outboard stack is missing.
The stored characteristic data is to include the following:
1) Main dimensions of the ship
2) The position of each bay from the aft perpendicular
3) Strength limitations (for containers, lashing C£1uipment
and the ship)
4) General loading limitations.
A.7 Certification
Certification is carried out to ensure that the lashing computer
system works properly onboard and to ensure that the correct
approved version of lhe software ha:;; been installed.
The approved test conditions are to be tested on the lashing
computer system in presence of a surveyor from the Society,
before the la~hing computer certificate is issued.
During Lhe test, the securing arrangements calcuJated on the installed lashing computer system arc Lo be verified to be identical to the approved test conditions. If numerical output from
the lashing computer system is at variance with the approved
test conditions, a certificate can not be issued.
During the tests, at least one of the test conditions is to be built
up from scratch, to ensure that the calculating methods function properly.
Where the hardware is nm type approved, the test is to be carried out on both the first and the second nominated computers
prior to the issuance of the lashing computer cenificate. The
two nominated computers are both to he identified on the certificate.
After completion of satisfactory tests, the lashing computer
certificate is to be issued .
The following is to be listed in the lashing computer certificate:
Program description is not required for type approved software.
In some cases where the functionality and principles are not
clear the entire program may need to be submitted for evaluation at the discretion of the Society.
The test conditions are to be as follows:
1) Name of vessel, name of yard, yard number and year of
built for the vessel.
2) Software name, software version.
3) Software manufacturer name and address.
4) If lhe software is type approved; type approval certificate
number.
5) Hardware name, serial number and manufacturer.
6) Name and serial number of the second nominated computer or type approval certificate number.
7) J.dentifa:ation of the approved test conditions used for the
certification.
l) Typical stowage in hold
2) Mixed stowage, if applicable
3) Typical stowage on deck
The lashing computer certificate and the approved test conditions are to be kept onboard attached to the user's manual.
The certification is to be carried out onboard.
The program description is to contain the following:
Description of functionality, including flow chart-;
2) Descriptions of calculation methods and principles.
1)
DET NORSKE VERITJ\S
22
August 2003
Appendix B
Calculated examples
properties is given below.
In this appendix the following calculated example~ are given
using both tl1e direct analysis method and the formula based
method:
Table B-1 Container clement.;
Top and hotrom
Section
characteristic
beam
Ay
I x 10 10 11Jm2
A,
I x 1010 mm2
8.2.'I Four tier stack with two
analysis method)
cro~~
I x 1olO nun2
Ix 10IO nun4
1 x I otu rrun 4
1 x io10 mm 4
Ix HP mm3
Ix HP mm3
Ix 107 mm3
A,
B.1.1/B.1.2 Three tier stack with single lashing, no windload
I.
lrtshinr;. winrllmrl (rlirec1
Iv
I,
B.2.2 Four tier stack with two cross lashing, no windload (formula based method).
W,,
B.1 Three tier stack with single lashing
w7
w.
e"
()
B.1.1 Direct calculation method
c,
()
Three-tier high 40' standard ISO container stack with single
cross lushing to top of tier I, see Figure B-1. (Note that wind
loads are not included in the example and that a CoG of 50%
have been utilised)
f.,
f,
I
I
Ix:
A~.:
Wy:
ly: ·.
A
Wz:
Height of
twist lock
25m m
Side beam,
door less end
1 x. 1010 rrun2
1 x 10LO uun2
160 nun2
1x10LO mm4
1 x.1010 mm 4
1x1010 mm4
l x 107 mm3
l x 107 nun3
l x 107 mm3
1
I
0
0
1
1
Profile properties:
Ax:
W x:
t
Side beam,
duorend
1 x 10 10 mm2
1 x IOIO mm2
62mm 2
Ix 10 10 mm4
I x 10 10 mm4
1 x 10 10 mm4
l xl07 mm3
1x107 rnm3
1x107 mm'.l
0
0
lz:
ey:
ez:
f_y:
fz:
Axial area (total profile area)
Torsion section modulus
Torsional moment of inertia
Shear area in local z-direction
Section modulus about local y-axis
Moment of inertia about local y-axis
Shear area in local y-direction
Section modulus about local 7.-axis
Moment of inertia about local z-axis
Shear centre distance from vertical neutral axis
Shear centre distance from horizontal neutral axis
Shear faclor in local y-direction
Shear factor in local z-dircction
The twistlocks are modelled with element properties according
to Table B-2 and filled with hinges in the top end.
Table B-2 Twistlock elements
Section characteristic
Ax
Av
A,,
Figure H-1
Ix
Iv
Iz
f'..eneral data:
Wx
W.,,
Container weights:
Twistlocks:
Lashing rods:
30 t (all ti.ers)
SWL 250 kN (between each tier)
Steel, diameter 25 mm
S\VL250 kN
Transverse accelerations:
Tier 1:
6.67 m/s2
Tier 2:
6.67 m/s2
Tier 3:
6.67 m/s2
Vertical acceleration:
Tier 1-3
7 .60 m/s2
Rollangle,
27°
<I>
w7.
ev
e"'
fv
f,._
Twistlocks
40000 nuu2
I x 1010 mm2
}J(JOL0mm2
1 x JOL0mm 4
1 x JOlOmrn 4
1x1010 mm 4
1x 101 mm3
l x 107 mm3
1x107 mm3
0
0
l
l
Lashings:
Lashings are modelled a.~ a pipe section with diameter of 25
mm and a wall thickne.~s of 12.4 mm. The mate1ial for the rod
is defined according to the following:
= .J259l2 + 243S2 =3558 mm
E =0.04 (l -1000) =40 (3558 -1000) = 102320 N/mm2
2
l
Geometry:
The containers are modelled with clements according to Table
B-1 Lo get the correct racking stiffness. Definition of section
= 102.3 kN/mm
v=0.3
For simplicity rf:asons the twistlocks and lashing rods arc attached to the extreme corners or the container. The lashing
rods must be given truss properties, alternatively beam proper-
DET NORSKE VRRITAS
23
August2003
tics with hinged coIU1ection to the corner casting in order to
avoid bending moments in the lashing rod. The lashing rods
arc tension members only. Therefore, only the lashing subjected to tension loads should be modelled, see Figure B-2.
fcg
= 0.5 since CoG is set at 50';ifJ
Tier 1-3
Bottom nodes
Top nodes
PT,node = 25.0 kN
PT,node =25.0 kN
Vertical force per bottom corner node
M · g ·cos¢
Pv,node
-
= (2 . 2)
Tier I- 3
Bottom nodes
FigureB-2
Results:
The maximum resultant forces are presented in Table B-3. Acceptance criteria according to Ch. 4.2 and as given in this example have been used.
Load1>:
The transverse force is divided between the two sides of the
container (50% each) and between the four corners of each side
in relation to the centre of gravity.
LC4 is not calculated in the beam analysis since it is a relatively simple check of the racking force in the containers this is
easy checked by using a simplified analysis.
LCt
Transverse force per corner node
f\v
P...
•1,node=( 2 · 4 )+
M ·at · .l~g
(2 . 2 )
fcg = 0.5 since CoG is set at 50%
Tier 1-3
=25.0 kN
PT,node =25.0 kN
Bottom nodes
Top nodes
PT,node
R
Pv.node == 65.6 kN
_M·g
V,node - ( . )
2 2
Tier 1- 3
Bottom nodes
Pv,node
=73.6 kN
LC2
Tier I- 3
Pv.nodc
Bottom nodes
=130.6 kN
LC3
l\v
flr',node=(2·4)+
Force
Notes
151.1
549.4
Doorless end
Doorle:;s end
Pass
OK
OK
82.6
181.8
Doorless end
OK
157.4
Door end
Not
OK
1,3 168.9
Vertical
I
Horizontal shoring forces on comers
Lower, tension
Lower
compression
Upper, tension
1,3 75.5
Upper
1
compression
Door end
OK
Not relevant
Not relevant
OK
OK
Not relevant
Door end
OK
OK
Tension in
twistlock
Shear in twistlock
Tension in lashing
rods
Vertical support
force at bottom of
stack
-
-
I
3
181.8
Doorlcss end
OK
2
1,3
1,3
103.3
230.9
Door end
Door end
OK
OK
l
705.4
Into ship structure
I
B.1.2 Formula based method
Three-tier high 40' standard TSO container stack with single
cross lashing to top of tier l, see J-ligure B-3. (Note that wind
loads are not included in the example).
+ g)
(2 . z)
M(av
Pv,node =
T.ible B-3
Tier LC
liem
Racking force
I
I
I
I
Corner post
compression
Vertical tension in
I
3
top corner
Vertical tension in
l
3
bottom comer
Lashing load.s in comer casting
1,3
I
Horizontal
M ·a1. fr:g
(2·2)
General data:
Container weights:
Twistlocks:
Lashing rods:
30 t (all tiers)
Steel, diameter 25 nun
SWL 250 kN
Transvcl'se accelerations:
6.67 mfs2
Tier 1:
Tier 2:
6.67 m/s2
DET NORSKE VERITAS
24
August 2003
Ye1tical support force (see 7.2.3):
6.67 m/s 2
Ticr3:
Psh
Tier 1-3
7.60m/s2
Rollangle. qi
27°
-- (4.5·100- l ·99.7)· 2591
2258
402.0 kN
Lashing force:
p.
= 99. 7 ..f~25_9_12_+_24
_3_8_
i
11
145.5kN (< 250)
2438
\/,..._.,!,.,..1 ........ _ _ ......... ,..,_ ..... CI ...... \...!--.&'..... - ........
v ""' "'"''.u \.-V1uvv.uvu" v1
.la~.u.u.ao
.Lv1vc.
2591
pl =99.7-=106.0kN (<300)
s
2438
n=3
Combined vertical support forces (see 6.2.10):
Compression side
Psc = 0.25 · 3 · 30· (9.81+7.60)= 391.7 kN
f'sc =0.25· 3· 30·9.81+402.0+106.0=728.7kN
i=I
=> Psc =728.7 kN (into ship structure)
Tension Side (Psi= 0))
P.~,
=0.25. 3. 30· 9.81·cos27° -402.0 ==- 205.3 kN (< 250)
Twistlock with SWL= 250 kN.
Compressive force in lowermost container (see 6.2. l l ):
Pc =0.25· 2·30· (9.81+7.60)= 261.2kN
Figure B-3
~· =0.25 ·2 ·30· 9.81+402.o- 100 · 25 ~ 1.+106.0=597.8 kN
.
Horizontal force per container end:
=
=> Pc=597.8 kN (<864)
=
Ph 'h x 30 x 6.67 l 00 kN
Lashing (See Ch. 7.1.3):
Racking force in lowest container (see 6.2.12):
= 491 mm2
= 2591 mm
= 2438 mm
A1
h1
s1
l1=
E1 =
)
s, =2· 100+0.5· 100-99.7
3558 mm
40 (3558 - 1000) = 102320 N/mm2 =102.3 kN/mm2
K . = 102.3 · 491·2438'
~(2591' + 2438')
2·2258
= 150.3 kN ( "'150)
Calculation for door end walls
End wall racking stiffness (see 6.2.2): Kc= 3.85 kN/mm
Free displacement at level i (see 6.3.2):
1
=6.63 kN/mm
0.0 =-(0.5·100+ JOO+ 100)=64.9 mm
3.85
I
Horizontal support force of lashing (see 7.5.2):
Calculation for doorless end walls
End wall racking stiffness (see 6.2.2): Kc= 10 kN/mm
Free displacement at level i (see 6.3.2):
o.0 = 101 (0.5·100+100+100)= 25.0 mm
I
Horizontal support force of lashing (see 7.5.2) :
P. = l0· 2:5.0 =997kN(<l50)
/'I
~
10
...•
-+I
6.63
P,; =
(J
8 64
:; ·)
--+1
6.63
158.lkN (> 150, Notok!)
Ve1tical support force (see 7.2.3):
p = (4.5·100-1·158.l)· 2591=
_ kN
334 9
sh
2258
Lashing force:
P..
,,
=15 8.1 .J259 I2 + 2438
2438
2
230.7k:N (< 250)
Vertical component of lashing force:
2591
Pl =158.1-=168.0kN(<300)
s
DET NORSKE VERITAS
2438
25
August2003
Combined vertical support forces (see 6.2.10):
Compression side
P,.c = 0.25· 3 · 30 · (9.81+7.60) =391 .7 kN
f'..sc =0.25 ·3 · 30·9.8 1+ 334.9+ I68.0=723.6kN
=> Psc
=723.6 k.N (into ship structure)
Tension Side (Psl = 0)
P~.1 = 0.25 · 3 · 30· 9.81·cos27°-334.9=-138.2 kN (< 250)
Twistlock with SWL = 250 kN.
Compressive force in lowermost container (see 6.2.11):
Pc= 0.25 · 2 · 30· (9.81+7.60) =261.2kN
Pc =0.25·2·30 ·9.81+334.9-
100 . 2591
.
S - +168.0= 596.9kN
2 243
=> Pc = 596.9 kN (<864)
FigureB-4
Sr
= 2·100+ 0.5 · I00-158.1=91.9kN(< 150)
Geometry:
The containers are modelled with elements according to Table
B-4 to get the correct racking stiffness. Definition of section
properties is given below.
Tipping moment I Pull out force for tier 2.
Vertical support forces:
= (2·100_-l-0)·2591 =229.5 k.N
p
sh
2258
Tuble B·4 Container elements
Section
Compression side
Psc =0.25· 2· 30· 9.81 +229.5=376.7kN
Side beam,
door end
J x !Ol0mm2
l x 1010 mm2
Iy
Ix 1010 mm2
1x1010 mm4
62mm2
1x1010 mm4
Ix 1010 mm4
1 x tOLO mm4
lxJ07mm3
l x 1010 mm2
160 mm2
l x 10 10 mm4
1x10 10 mm4
1x1010mm4
l x 107 mm3
1x107 mm3
l x 107 mm3
l x 107 mm3
1x107 mm3
0
0
0
0
1
1
Av
Av
Tension Side
Pst
Top and bottom
beam
1x1010 mm2
Ix 1010 mm2
characteristic
= 0.25 · 2 · 30· 9.81·cos27°- 229.5 =-98.4 kN (< 250)
Az
Iv
1 x JO!O mm4
B.2 Four tier stack with two cross lashings
I,
B.2.1 Direct calculation method
Four-tier high 40' standard JSO container stack with two cross
lashing, wind load included, see Figure B-4.
Wx
Wv
Wz
l x 1010 mm4
J x 107 rrun3
1 x 107 nun3
1 x 101 nun3
General data:
Twist locks:
Lashing rods:
ez
e~
Steel, diameter 25 mm
SWL250kN
Mass
Tier 1:
Tier 2:
Tier 3:
Tier4:
30
30
30
3
Transverse acceleration, at:
6.10 m/s2
6.25 m/s2
6.40 m/s2
6.55 m/s2
Tier 1-3
4.20 mJs2
Rollangle, <1>
Windload, Pw
25°
37kN
fv
fz
0
0
1
1
I
1
Side beam,
door less end
1x1010 mm2
Profile properties:
Axial area (total profile area)
Tor.sion section modulus
Torsional moment of inertia
Shear area in local z-direction
Section modulus about local y-axis
Moment of inertia about local y-axis
Shear area in local y-direction
Section modulus about local z-axis
Moment of inertia about local z-axis
Shear centre distance from vertical neutral axis
Shear centre distance from horizontal neutral axis
Shear factor in local y-direction
Shear factor in local z-direction
The twistlocks are modelled with element properties according
DET NORS KE VERITAS
26
August 2003
to Table B-5 and fitted with hinges in the top end.
LCl
Transverse for.ce per comer node
M ·at · .1·cg
p.
•a..
w
T ,node=(2 · 4 )+
(2 . 2)
Table B-5 1\vMlock elements
Section characteristic
A,
Av
Twistlocks
40000mm2
w.
Ix 1010 mm2
Ix l010 mm2
I x 1010 mm4
I x 1010 mm 4
Ix 10 10 mm4
Ix 107 mm3
l x 107 mm1
I x 107 rnm1
Cv
()
c,
()
A.
Ix
t.
I,
w.
WY
fv
I
f,
1
fcg
Tier 1
Hottom nodes
Top nodes
='.lY.~ kN
PT,node =25.2 kN
PT,no<le
Tier 2
Bottom nodes Pr.node = 30.4 kN
Top nodes
Pr.node= 25.7 kN
Lashings arc modelled as a pipe section with diameter of 25
nun and a wall thickness of 12.4 mm. The material for the rod
is defined according to the following:
For lashing to first tier
E 1 =0.04 (l - 1000) 40 (3558 - IOOO) = 102320 N/mm2
l 02.3 kN/mm2
=
=0.55 for bottom and 0.45 for top nodes
=
v =0.3
Tier3
Bottom nodes
Top nodes
PT.node
PT.node
=31.0 kN
=26.2 kN
Tier4
Bottom nodes
Top nodes
PT,node
=7.3 kN
PT.node =
6.8 kN
For lashing to second tier
E2 =0.04 (l - 1000) = 40 (5727 - 1000) = 189080 N/mm2 =
189.1 kN/mm2
v =0.3
For simplicity reasons the twisllocks and lashing rods are attached to the extreme comers of the container. The lashing
rods must be given truss properties, alternatively beam properties with hinged connection to the corner casting in order to
avo.id bending moments. The Lasing rods arc tension members
only. Therefore, only the lashing subjected to tension loads
should he modelled, see Figure B-5.
M·g
= (2 . 2 )
Pv,node
Tier 1- 3
Bottom nodes Pv,node =73.6 k.N
Tier4
Bottom nodes Py ,node = 7.4 kN
LC2
R
_M(av +g)
( . )
2 2
V,node -
Tier I- 3
Bottom nodes Pv,no<le = I 05. I kN
Tier4
-Figure B-5
Bottom nodes
10.5 k.N
Pv,node =
LC3
--
f\,v
Pr,node =(z. 4 )+
fcg
Loads:
The transverse force is divided between the two sides of the
container (50% each) and between the four corners of each side
in relation to the centre of gravity.
LC4 is not calculated in the beam analysis since it is a relatively simple check of the racking force in the containers this is
easy checked by using a simplified analysis.
M . ai . i~:x
(2 · 2 )
=0.55 for bottom and 0.45 for top nodes
Tier I
Bottom nodes
Top nodes
Tier2
Bottom nodes
Top nodes
DET NORSKE VERITAS
kN
Pr.node= 25.2 kN
PT.node= 29.8
PT.node =
PT.node =
30.4 kN
25.7 k:N
August2003
27
B.2.2 Formula based method
Four-tier high 40' slandard ISO container stack with two cross
lashing, no wind load included, see Figure B-6.
Tier3
Bottom nodes
Top nodes
Ticr4
Bottom nodes
Top nodes
PT,no<le = 31.0 kN
PT,no<le = 26.2 kN
PT,no<le
PT,nodc
General data:
Twistlocks:
=7.3 kN
=6.8 kN
SWL 250 kN
(between each tier)
Steel. diameter 25
Lashing rods:
mm
SWL250k.N
P.
_ M · g · cos¢
V,node -
Tier I- 3
Bottom nodes
Tier 4
B ottom nodes
Tier I:
Tier2:
Tier 3:
Tier4:
Pv,nodc = 66.7 kN
Pv,nodc = 6.7 kN
Results:
The maximum resultant forces are presented in Table B-6. Acceptance criteria according to Ch. 4.2 and as given in this example have been used.
TableB-6
[tern
Tier LC Force
Racking force
1
l
139.5
754.8
Corner post
:1
l
compression
Vertical tension
1
3
89.3
in top comer
Vertical ten8iOn
I
174.8
3
in bottom corner
Lashing loads in corner casting, tier I
Horizontal
I
1
120.9
Vertical
1
1
129.7
Lashing loads in comer casting. tier 2
Ho1izontal
2
1
113.4
Vertical
2
l
243.3
Horizontal shoring forces on corners
Lower, tension
Lower
compression
Upper, tension
Upper
1
58.0
J
compression
-
Tension in
twistlock
Shear in
twistlock
Tension in
lashing rods, I
Tension in
lashing rods, 2
Vertical support
force at bottom
of stack
Transverse
acceleration, a1:
6.10 mfs2
6.25 m/s2
Mass
(2 . 2 )
-
-
Notes
Doorless end
Door end
OK
OK
Doorless end
OK
Doorless end
OK
Door end
Door end
OK
OK
Door end
Door end
OK
OK
Nol relevant
Not relevant
OK
OK
Not relevant
Door end
OK
OK
30
30
30
3
6.40 m/s2
6.55 m/s2
Tier 1-3
Pha
91.5 kN
93.8 kN
96.0 kN
9.8 kN
4.20 mJs2
25°
Rollangle, <I>
-
n=4
j=2
i=I
Figure B·6
1
3
174.8
Doorless end
OK
I
I
101.4
Doorless end
OK
I
1,3
177.3
Door end
OK
2
1,3
268.5
Door end
Not
l
I
867.7
lnto ship structure
Lashings (see 7 .1.2):
=.J2591
l.l
2
+ 24382 =3558 mm
l . =~(2 · 2591 )2 + 2438 = 5727 mm
2
OK!
J
E; = 40 (3558 - 1000) =102320 N/mm2 == 102.3 kN/mm2
Ej = 40 (5727 - 1000) = 189080 N/mm2 = 189.1 kN/mm2
2
K.
I
~(259l1+24382 Y
K .=
,
102.3·49 1·2438 = 6 .63 kN/mm
2
189.1·491 ·2438
~((2. 2591)2 + 2438'
DET N ORSKE VERlTAS
r
=2_94 kN/mm
28
August 2003
Calculation for doorless end walls.
End wall racking stiffness (see 6.2.2): Kc= 10 kN/mm
Pree displacement at level i and j (see 6.3.2):
1
8.0 == - (0.5 · 91.5 + 93.8 + 96.0 + 9.8)== 24.5 mm
Calculation for door end walls.
End wall racking stiffness (sec 6.2.2):
lO
I
Sr = 0.5 ·91.5 + 93.R + 96.0 + 9.8 - 73.8- 60.0= 11 l.6k.N (< 150)
K =3.85 kN/mm
Free displacement at level i andj, modify values from doorless
end:
l
t5 ;n = -;--;:_ (0.5 · (91.5 + 93.8)+ 96.0 + 9.8 + 93.R + 96.0 + 9.8) = 39.8 mm
"
= 24.5 -IO ··= 63.6 mm
8,,.,
'"
!\/
:3.X.:5
JO
oJ.0 = 39.8 = 103.4 mm
3.85
Horizontal support force of lashing (see 7.7 .2):
10
1J1·39.8 -(+ 2)24.5]
2 94
P.=
73.8kN(< l50)
·
ri
+ 1)(_!Q__ + 2)
6.63
2.94
Horizontal support force of lashing:
1
1' -(-HI
3.Ss[l ·
pri
63
P,; = (
1 ~· +1
6.63
x
JO
)
- - +2 -1 2
2.94
2.94
6.63
(0.5. 91.5+ l.5 ·93.8 "': 2.5 ·96.0 +3.5 . 9.8 -1 ·?3.8-2 ·60.0)· 2591 ='.306.0 kN
2258
2.94
Vertical support force:
P = (0.5 .91.5 ~ 1.s-•n.R + 2.5·96.0+ 3.5 ·9.8-1·•n.4-2 ·91.l). 2590 =
. kN
207 8
22511
di
lL
1'J
Lashing force:
= 73 .8 ../2591
P . = 60.0
91.lkN {< 150)
(3.8~ + i)(3.85 + 2 ) _ 11
r1
Lashing force:
P.
= 97.4 kN (< 150)
85
3.8J(36·63
+1}03.4-1 ·63.3]
p. = 1 ·
60.0kN(<ISO)
Ve1tical support force (see 7.3.3):
,,
"'
103.4- (~+ 2)63.6]
( & )(
)
1' - 3. 5 + l 3 .85 + 2
6.63
1{( ~+ 1}9.8-1·24.5]
1
=
2
2
+2438
2438
107.7 kN (< 250)
P . = 107.7
1!
~(2 . 2591)2 + 24382 = 140.9kN (< 250)
2438
97
.4 =142.2 kN (< 250)
73.8
9
Pl. == 140.9 1.l =213.9kN (< 250)
J
60.0
Vertical component of lashing foi:ce:
Vertical component of lashing force:
2591
p ,. == 97.4- - == 103.5 kN ( < 300)
2591
P 1. =73.8 - - = 78.4k.N (<300)
SI
2438
s
2438
!
2·2591
P 1. = 91.1 - - · ""193.6kN(<300)
2 2591
p . =60.0 .
= 127.SkN (<300)
~1,,
2438
2438
SJ
Combined vertical support forces:
Compression side
Combined ve1iica1 support forces (see 6.2. 10):
P~c
Compression side
P sc = 0.25 · (3 · 30 + 3) · (9.8 l + 4.20)= 325.7 .kN
=0.25 · (3 · 30 +3)· (9.81+ 4.20) = 325.7 kN
Psc = 0.25· (3· 30+3)·9.81+207.8 + 103.5+ 193.6:::733.0kN
Psc = 0.25 · (3 · 30+ 3) ·9.81+306.0+78.4+127.5 = 740.0kN
=> Psc =733.0 kN (into ship structure)
=> Psc =740.0 k.N (into ship structure)
=
Tension Side (P 51 0)
Ps1 = 0.25 · (3 · 30 +3)· 9.81·cos25°-306.0= - 99.3 kN (< 250)
Twistlock with SWL =250 kN.
Pc= 0.25 · (2· 30+ 3)· (9.81+4.20) = 220.7 kN
Pc== 0.25 · (2 · 30 + 3) · 9.81+306.0 -
9
25
?!
1.5 ·
+ 78.4+127 .5::: 613.9 kN
2·225R
Tension Side (Psr = 0)
Pst =0.25 · (3 · 30+ 3)· 9.81 ·cos25° - 207. 8 = -1 . lk.N (< 250)
Twistlock w1lh SWL =250 kN.
P,: =0.25 · (2. 30+ 3)· (9.81+ 4.20) = 220.7kN
9
259 1
Pc =0.25·(2· 30+3)· 9.81+207.8- 1.5
+I03. 5+193.6 = 607.6kN
2· 2258
=> Pc= 607 .6 kN (<864)
=> Pc = 613.9 kN (<864)
DET NORSKE VERITAS
29
August 2003
Sr = 0.5 ·91.5 +93.8 +96.0+9.8-97.4 - 91.1 = 56.9kN(<150)
Racking and Tipping moment I Pull out force for tier 2.
Doorless end:
Compression side
f'sc
=0.25 ·63·9.81 +178.3=332.8k.N
Tension Side
Pst = 0.25 · 63 · 9.81·cos25° -178.3 = - 38.3 kN (< 250)
Vertical support forces due to horizontal forces:
2591
p1 =
(0.5·93.8+1.5·96.0+ 2.5·9.8 - 60.0)=178.3 kN
si 2258
DET NORSKE VERITAS

ci9- V950

Transcription

Similar documents

Winter Ice Art

open and inspect shipping containers in a secure

1_innopas pi/iisc modular tunnel pasteurizer

Our 45` HC pallet-wide container carries five more feet of

instructions

Our 45` HC pallet-wide container carries five more feet of

Dalton`s Postulates - Evan`s Regents Chemistry Corner

Propane Setback Flyer - Skagit Farmers Supply