IACS Common Structural Rules Knowledge Centre

Bulker Q&As and CIs on the IACS CSR Knowledge Centre
KCID
No.

Ref.

Type

4/3.2.2.1 &4/3.2.2.2
283 & 5/1.4.2.1
Question
attc & 5/1.4.2.2& 5/1.4.2.4& 5/1.4.3.1

348 5/App1.2.2 question

Topic

design stillwater
bending
momentHull girder
ultimate
strengthDatecompleted

Question/CI

2007/1/16

Design still water bending moments in CSR Bulk rules - 3 sub-questions withdiagrams (see attachment)

2009/9/4

1) In Ch 5, App 1, there are editorial errors in the formulae for critical stresses
in the following requirements:[2.2.4] - Beam column buckling[2.2.5] - Torsional buckling of stiffeners[2.2.7] - Web local buckling of flat bar stiffeners
The correction should be to delete the coefficient in the brackets in formulae
giving critical stresses.Please confirm?
2) In Ch 5, App1, [2.2.8] - Buckling of transversely stiffened plate panels, thecoefficient is missing in the second line of the formula giving the critical sress,
between ReH and the first bracket. Please confirm?

Attachment

Answer

Question 1 . We assume the figure in attached file is related to the Fig 2 of Ch
4 Sec 3 [2.2.2] using the formulas of MSW,H & MSW,S and the extent within
0.4L amidships is shown by parallel line drawn in blue color in attached file. In
addition the values of the blue line at AE & FE should not be 0 but should becorrected as 0.2MSW in line with Fig 2 of Ch 4 Sec 3 [2.2.2]. At the end of thedesign process the still water bending moment used for scantling check and
FEA has to represent the individual envelope curve (CH4, Sec3, 2.1.1, first
sentence). This corresponds to the green line in the figures.
Question2 . Ch 4, Sec 3, [2.2.2] should be considered only as a preliminary
distribution of SWBM. It is not a minimum value of SWBM. Regarding thestrength point of view, the section modulus is to be checked according to its
minimum value (see Ch 5, Sec 1, [4.2.1] and [4.2.4]), and to its value basedon the permissible distribution of SWBM (see Ch 5, Sec 1, [4.2.2] and [4.3.1])
which may be the preliminary value of SWBM, if the permissible one comingfrom loading booklet is unknown.
Question 3. There is definition of a value of the SWBM in flooded condition. It
has to be calculated and included in the loading booklet and used for the
checking of hull girder strength according to Ch 5, Sec 1, [4.2.2] and [4.3.1], in
addition of the checks in intact condition.

Your observations were correct and the equations were amended in RCN No.
1 (Nov 2007), with further amendments in RCN No.1-1 to the July 2008 Rules.

Page 1 of 7

YIACS Common Structural Rules Knowledge Centre

KCID
No.

353
attc

Ref.

5/1.2.2.2

Type

Question

Topic

Hull Girder

Datecompleted2007/4/2

Question/CI

Multiple Questions on Hull Girder Shear Force Correction. See attached

Answer

Attachment

Q1:(a) For the structures at forward and aft of transverse bulkhead the scantlings
should be determined based on (symbol: delta)QCF and (symbol: delta)QCA
respectively.
(b) Permissible limits should be also based on (symbol: delta)QCF and(symbol: delta)QCA respectively for structures at forward and aft of transverse
bulkhead.
Q2: (symbol: delta)QC should be calculated for each non-homogeneous
loading condition. Therefore the permissible shear force is different for each
non-homogeneous loading condition.
Q3: Shear force correction should be done at the bulkhead where adjacent
holds are in non-homogeneous loading condition. Therefore shear force
correction should not be done at other transverse bulkheads than those of
No.4 ballast hold.
Q4:(a) Total mass of cargo M may include deadweight such as water ballast andfuel oil tank in double bottom, bounded by side girders in way of hopper tankplating or longitudinal bulkhead, if this space is loaded for the nonhomogeneous loading condition considered.
(b) In [2.2.3] flooded water in the hold may be included into M.
(c) Deadweight in double bottom which is as defined in (a) may be included
into M.
Q5: Yes.

Y

Page 2 of 7

IACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

365

Ch 5 Sec1

366

Ch 5 Sec2

Type

Question

Topic

Strength of
Hull Girder

Datecompleted

Question/CI

Attachment

Answer

2007/5/11

Longitudinal strength of hull girder in flooded condition is given in Ch 5 Sec 1
for BC-A and BC-B only. We assume that this is not required for BC-C andships below 150 m in length. Please confirm.

Yes, your assumption is right.
The current CSR requires to BC-A, BC-B and BC-C ships to check the hull
girder ultimate strength under not only intact condition but also flooded
condition but the yielding check of hull gider under flooded condition isrequired for BC-A and BC-B ships, and not required to BC-C ships.
In order to resolve this discrepancy, it is decided that the yield check of thehull girder is to be performed for BC-A, BC-B and BC-C ships.
This will be considered as a rule change.

As mentioned in the requirement Ch 5 Sec 2 [1.1.1], the requirement on
ultimate strength check of hull girder apply to ships equal to or greater than
150m in length (L), i.e., BC-A, BC-B and BC-C ships.

Question

Hull girder

2007/3/20

Longitudinal strength in flooding condition is given in Sec 1 and is limited to
BC-A and BC-B ships only. We assume that the same limitation applies to
Sec 2 for ultimate strength of hull girder in flooding condition. Please confirm.
If so, please add the limitation in Sec 2 as well.

428 5/App1.2.2
Question.8
attc

Formula2007/4/19

For a more clear application of the formulae of the requirement Ch 5,
In Ch 5, App 1, [2.2.8], it could be some interpretation on “l” in the formula
Appendix 1, [2.2.8], please refer to the file attachement "Draft Answer Ch 5,
giving “sigmaCR5”, and of “s” in the formula giving “betaE”.In order to apply
such formulae in the right way, it could be useful to specific the exact definition App 1, [2.2.8].doc".
of the parameters “l” and “s”.
Also Included in Corrigenda 5

2007/6/12

According to a draft reply to KC #353, hull girder shear force correction is only
considered at bulkheads where adjacent holds are in non-homogeneous
loading. In our opinion, this is valid when permissible limits Qp is establishedaccording to [5.1.3] considering shear force correction Delta-Qc. Q1: In our
opinion, such shear force correction should only be considered to theA1:The understanding is correct.
permissible limit giving the same sign to actual shear force at that bulkhead
A2:Shear force correction is to be considered only at the bulkhead where
position and the permissible limit of opposite sign need not be corrected.
adjacent holds are in non-homogeneous loading condition. Therefore shear
Please confirm. Q2: For the determination of the required scantlings according
force correction should not be done at other transverse bulkheads than thoseto [2.2.2], however, shear force correction Delta-Qc should in principle beof No.4 ballast hold. In that case, shear force correction in point A is notconsidered at every bulkhead for non-homogeneous loading conditions. As
relevant.
explained last time, hull girder shear force will increase after shear force
correction, in case of heavy ballast conditions, at the aft bulkhead of the holdaft of the heavy ballast hold thereby requiring larger scantlings. See Point-A in
the attached figure. Same issue at the forward bulkhead of the hold forward of
the heavy ballast hold.

453
attc

Ch.5
Sec.1

Question

Shearforce
correction

In our opinion, this reflects physics behind shear force correction. In case of alarge Capesize bulk carrier, this effect is not negligible giving impact on therequired scantligs. Please confirm.

Page 3 of 7

YYIACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

5/1.5.1.2,
459 5/1.5.1.3 ,attc 5/1.5.3.2,& 5/1.5.3.3

460

6/3, 5/2

Tanker App
A/2.2.2.3
499& 2.2.2.4;
attc& Bulker- Ch.5, App
1. 2.2.2

Type

CI

CI

CI

Topic

Shear
Stresses &Shear
ForcesOrdinary
Stiffeners &Stiffened
PanelsHard corners
in the Hull
GirderUltimate
StrengthDatecompleted

Question/CI

Answer

Attachment

2007/7/2

Please see the attachment for question containing several figures.
Note that reference is made to KC #353 and to the supplementary questions
KC #453 submitted on 20 April 2007.

In CSR for bulk carriers, they are two different ways of assessing shear
stresses and shear forces:
1 - using direct calculation, as stated in 2.2.1, and in such a case thepermissible still water shear force is obtained through 5.1.2, OR
2 - using simplified calculation with correction of shear force as stated in 2.2.2,
and in such a case permissible still water shear force is obtained throgh 5.1.3.
Both approaches are not to be mixed, and generally the direct calculation
approach is used.

Y

2007/7/13

Ch. 6 Sec. 3 Bucking & ultimate strength of ordinary stiffeners and stiffened
panels.
According to [1.1.2] buckling assessment of longitudinal material is not
required for flooding conditions.
According to URS 17 buckling check is required for flooding condition.
Quote: S17.5 - Strength criteria
The damaged structure is assumed to remain fully effective in resisting the1)Yes. Your assumption is correct.
applied loading.
2)Yes. Your assumption is correct.
Permissible stress and axial stress buckling strength are to be in accordancewith UR S11.Unqoute.
The Ch. 5 Sec. 2 HULS is calculating axial stress buckling of hull girder due toflooding bending moment.
Q1. We assume that CSR fulfils URS17.5 by HULS check of Ch. 5 Sec.2.
Please confirm
Q2. We assume that buckling according to Ch. 6 Sec. 3 need not becalculated in flooding condition as outlined in [1.1.2]. Please confirm.

2007/10/9

The CSR for Oil Tankers and for Bulk Carriers need to have the samedefinition of hard corners in the Hull Girder Ultimate Strength.
The attachment is a proposal for a common interpretation in this respect.
The differences between the Rules in force are:
CSR for Oil Tanker:The area on which the value of the buckling stress oftransversely stiffened panels applies is to be taken as the breadth between
the hard corners, i.e. excluding the end of the hard corner if any. Refer to KC
CSR for Bulk Carriers: The definition is too vague and needs improvement
through this CI.

The hard corners in the hull girder ultimate strength is defined as shown in the
figure of the attached file “Fig._KC499.pdf”.

Page 4 of 7

YIACS Common Structural Rules Knowledge Centre

KCID
No.

Ref.

519 Ch5 App1
2.2
attc

Type

CI

Topic

Ultimate
Strength by
Incremental iterative

Datecompleted2008/2/7

Question/CI

Attachment

Answer(A1) Where materials of plate and stiffener are different, two calculations arecarried out:
With regard to calculation procedure for ultimate strength by incremental1) for the stiffener: by adding to the stiffener an attached plating of the same
iterative approach, please be clarified three questions as follows.
material as the one of the stiffener, then determine the shortening curve and
Q1. Shortening curve for a stiffened plate element where material of plate andthe stress σ to be applied to the stiffener.
stiffener are different.
2) for the attached plating: by adding a stiffener made of the same material as
Q2. Shortening curve for an element where thickness of plate are different.
the one of the attached plating, then determine the shortening curve and the
The element can be stiffener or plate.
stress σ to be applied to the attached plating.
Q3. Shortening curve for an element where material and thickness of attachedplate are different.
(A2):An average thickness by the area of each considered plate is used for the(Attachment included)
considered element.

Y(A3): An average thickness and yield strength by the area of each considered
plate is used for the considered element.

520 Ch5 App1/
2.1.1.,
attc

521
attc

634
attc

BulkerCh5
App1/2.2

Ch.5,
Appendix1

For plates stiffened by not longitudinally continued stiffeners such as girders in If the stiffener is not continuous it does not participate to the hull girder
double bottom, how to divide the plate to calculation elements. Should theultimate strength and thus it is not to be taken into account.
stiffeners be neglected and considered as plate elements?
But it divides the plate into elementary plate panels which are calculated(Attachment included)
independently.

CI

PlatesStiffener

2007/10/23

CI

Length of
Stiffeners

For stiffeners where one side of web are supported by bracket which spaceless than the space of primary supporting members, which is length of this
2007/10/23
element, space of brackets or supporting members?
(Attachment included)

RCP

Load end
shortening
Curves2008/3/26

A change of the Rules regarding load end shortening curves set out in Ch.5,
App.1 is proposed.
In case that stiffeners and attached plates are of different materials in someareas of hull girder transverse sections, it is proposed that the stipulations
relating to the load-end shortening curves defined in Ch. 5, App.1 areexpanded as underlined in red in the attachment to meet such case for userfriendliness purposes.

Y

The length of the stiffener is taken as the space of primary supporting
members as it cannot be considered that a bracket on one side of thestiffener’s web is enough to reduce this length.

Y

Please refer to the answer in KC ID 519.
Y

We will consider the rule change proposal in order to clarify this.

Page 5 of 7

IACS Common Structural Rules Knowledge Centre

KCID
No.

685

788
attc

973

977

Ref.

Date
completed

Question/CI

AnswerShear force
for bucklingassessment

2008/5/30

Ch.6,Sec.3,[2.1.3] defines the shear force for buckling assessment as follows:
Q=Q_SW + C_QW x Q_WV.
There seems to be no limitation to the signs of Q_SW and Q_WV for their
combinations. On the other hand Ch.5, Sec.1, [2.2.1] reads: "When they are
combined, vertical shear forces Q_SW and Q_WV in intact condition are to betaken with the same sign."
Which way should be taken when calculating Q in Ch.6, Sec.3, [2.1.3]:a) Q to be calculated only for the combinations where Q_SW and Q_WV areof same sign, orb) Q to be calculated for all combinations where Q_SW and Q_WV are ofeither same sign or opposite signs ?

Hull girder shear stress check should be performed at the maximum absoluteshear force. Such case occurs at the combination of either(1) Q_SW_pos +(C_QW_pos x Q_WV), or(2) Q_SW_neg +(C_QW_neg x Q_WV), where,
C_QW_pos , C_QW_neg : positive and negative load combination factors
according to load cases as defined in Ch.4, sec.4,Table 3.
The sentence in Ch.5, Sec.1, [2.2.1], which is quoted in the question, reflects
this interpretation.
Therefore we will consolidate the paragraphs referring to shear force
combination into CH5, Sec1 [2.2.1] and replace CH6, Sec3, [2.1.3] with a notereferring to CH5, Sec1.

Permissible
still water
shear force

1)The designer should define the design still water shear force QSW in linewith Ch.4, Sec.3 [2.3] in the first place.
Ch4 Sec8 requires that the permissible value of still water shear forces be
described in loading manuals. “Permissible still water shear force” is defined in2) Then using QSW the following strength is assessed
Ch5 Sec1 [5] based on the calculated shear stresses of hull girder strength(a) hull girder shear strength according to Ch.5 Sec.1 [5].
members. Further, other strength assessments, such as global strength
2008/10/27(b) buckling strength according to Ch.6 Sec.3
analysis in Ch7 Sec2 and buckling strength assessment in Ch6 Sec3, also(c) global strength according to Ch.7 Sec.2.
refer to hull girder shear force. However, the relationship of shear force values
is not clear in CSR. (See attached) Please consider a rule change to clarify3) As a conclusion, the design still water shear forces can be taken as thethe above.
allowable ones and described in the loading manual. We will consider the
RCP in order to clarify this understanding.

Question

Hull girder
ultimate
strengthWith respect to hull girder ultimate strength
1. The scantling requirements by hull girder ultimate strength are to be applied
within 0.4L amidships in 9/1.1.1.2 of CSR OT. For CSR BC, It is noted that thenormal stresses are to be checked within L, please clarify whether the
2010/10/12
scantling requirements by hull girder ultimate strength are to be applied within
L in CSR BC or not.
2. Our understanding is that the modifications to CH5/Appendix 1 in bulker
rcn1 to July 08 are also applicable to CSR OT, please confirm.

Question

Applicationof shearstress checkType

6/3.2.1.3 &Question
5/1.2.2.1

5/1.5.2.2

Bulker
5/App.1 ,Tanker
9/1.1.1.2

5/1.3

RCP

Topic

2010/3/12

Attachment

1. This issue will be submitted to the Harmonisation teams.
2. We confirm the modifications to CH5/Appendix 1 in CSR/Bulk Carrier RCN1
to July 08 are also applicable to CSR OT. The Rules will be amended toincorporate those modifications.

From Ch.5 Sec.1 [3], we know that the check of normal stress apply along the
The check of shear stress and permissible still water shear force apply alongscantling length of the hull girder. How about the application of shear stressthe scantling length of the hull girder.
check and permissible still water shear force? Do they also apply along the
A corrigenda will be considered to clarify this.
scantling length? Please clarify.

Page 6 of 7

YIACS Common Structural Rules Knowledge Centre

KCID
No.

1051

Ref.

Text
5/1.2.2.2

Type

Topic

Date
completed

Question/CI

In CSR BC, there is no clear definition of a "homogeneous loading" condition.
This definition is important to know whether or not it is possible to make ashear reduction according to Ch5, Sec1, 2.2
Defenition of
We think it's possible to use the definition of homogeneous loading condition
Homogenous
given in URS 18:
Interpretati
loading2010/10/20 "...homogeneous loading condition means a loading condition in which theoncondition toratio between the highest and the lowest filling ratio, evaluated for each hold,make shear
does not exceed 1,20, to be corrected for different cargo densities."
reduction

Attachment

Answer

We agree with your proposal to use the definition of homogeneous loading
condition given in URS 18 in CSR for Bulk Carriers:"...homogeneous loading condition means a loading condition in which theratio between the highest and the lowest filling ratio, evaluated for each hold,does not exceed 1,20, to be corrected for different cargo densities."
The definition will be included in the Rules.

Please let us if you confirm this proposition

Page 7 of 7

KC#283
Design still water bending moments in CSR Bulk rules.
Ch.4 Sec.3 [2.2.1] and [2.2.2] and Ch.5 Sec.1 [4.2.1], [4.2.2], [4.2.4] and [4.3.1]
We assume the following interpretation is valid for design bending moments in intact
condition:

1. Rule minimum (Zmin.)2. Envelope for design
loading conditions

3. Envelope for loading
manual/instrument

Alt 2

3. Envelope for loading
manual/instrument

1(blue). Rule minimum Z (section modulus) is maintained within 0.4 L amidships
according to Ch 5 Sec 1 [4.2.1] and [4.2.4]. Corresponding bending moments are given as
preliminary design moments in Ch 4 Sec 3 [2.2.2].
2(green). Envelope curve for all loading conditions in the loading manual. For somepoints this may exceed the rule minimum requirement (ref. Ch.4 Sec.3 [2.2.1] and Ch.5
Sec.1 [4.2.2] and [4.3.1]).
3(red).
Envelope (permissible) curve for loading manual/instrument.
Q1: As long as the item 1 is satisfied, i.e., Rule min. Z is maintained within 0.4L amidships,
could “Alt 2” below be used as Envelope for the loading manual/instrument? Could “Alt 2”
be used for sig-x for local scantlings and for design bending moment for FEM calculation?
Note that the red line may have an uneven distribution within 0.4L amidships and might bebelow rule minimum (item 1 above).

Q2: In this connection, please clarify if Ch.4 Sec.3 [2.2.2] is a minimum requirement within
0.4L amidships or just a guidance. If it is not a rule minimum, and in case the Envelope (line2) is below Min. Z (line 1), hull girder capacity of min Z is not fully utilised by thedesign/permissible still water bending moments of the vessel. As far as we understand, this isgiven as a minimum requirement for design still water bending moment in the CSR-Tanker
rules. Please clarify.
Q3: For the flooding condition, we assume the following relationship. We assume that thesame principle also applies to harbour condition. Please confirm if our assumptions arecorrect.
20%MW

1. Intact envelope
2. Intact envelope + 20%MWV
3. Flooding envelope fromflooding of design conditions

4. Envelope for loading
manual/instrument

1. The intact bending moment based on above assumptions.
2. The Intact envelope + 20%MVW
3. The envelope curves from flooding of design loading conditions. This curve exceed
curve 2 for certain points.
4. Design limit for the flooding condition and envelope curve for loading
manual/instrument.

KC#353
Questions on hull girder shear force correction
The below questions except Q4 are based on a assumption that shear force
correction 'QC as defined in Ch.5 Sec.1 [2.2.2] is relevant during design
and approval stages. During in service, actual loading conditions will bechecked by the loading instrument based on the Qp as defined in [5.3.1]
without shear force correction in each loading condition.
Q1: When applying shear force correction according to Ch.5 Sec.1 [2.2.2],
there are two values of 'QC calculated at each bulkhead position for thefore and aft holds respectively as illustrated below. The scantlings should
then be determined (and strength is verified) based on the smaller of the'QCA and 'QCF in each loading condition. Permissible limits will then becorrected according to [5.1.3] with the maximum of these 'QC values ascalculated above for different loading conditions. Please confirm.
Q2: When the shear force correction is made to the permissible shear force
limits according to [5.1.3], shear force correction is only available either
positive or negative at each bulkhead position as illustrated below. Thisshould be applicable to alternate loading conditions and heavy ballast
condition but may not be applicable for new loading conditions with
uneven distribution of dead weight. Please confirm.
Q3: When the shear force correction is made for the heavy ballast condition,corrected shear force will “increase” at the aft end of the aft hold (Point A)
and fore end of the fore hold adjacent to the ballasted hold. How the shear
force correction should be made at such bulkhead positions? They may bedecisive. Permissible limit should then be “reduced” from nominal limit?
Q4: Cargo mass as defined in [2.2.2] include deadweight such as waterballast and fuel oil in the double bottom and hopper tanks excluding
topside tanks. In [2.2.3] flooded water in the hold is taken into account.
Dead weight in double bottom and hopper tank should be treated in thesame manner. Please confirm.
Q5: The above items should also apply to harbour and flooding conditions.
Please confirm.

Page 1 of 2

7

6

5

4

3

2

1

Nominal shear force
'QCA

'QCF

Corrected shear force

Alternate loading condition

7

6

5

4

3

2

1

Nominal shear force

Corrected shear force

Point A
Heavy ballast condition

Page 2 of 2

KC#428
For a more clear application of the formulae of the requirement Ch 5, Appendix 1, [2.2.8], thefollowing are to be considered:

EE

10 3

s H Re Htp
E

s: plate breadth, in m, taken as the spacing between the ordinary stiffeners,": longer side of the plate, in m

Filename:
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C:\Documents and Settings\IACSUser\My Documents
Template:
C:\Documents and Settings\IACSUser\Application
Data\Microsoft\Templates\Normal.dot
Title:For a more clear application of the formulae of therequirement Ch 5, Appendix 1, [2Subject:
Author:Zöe Wright
Keywords:
Comments:
Creation Date:
11/06/2007 3:43 PM
Change Number:
1
Last Saved On:
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Last Saved By:
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Last Printed On:
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As of Last Complete Printing
Number of Pages: 1
Number of Words: 39 (approx.)
Number of Characters:
226 (approx.)KC#453
7

6

5

4

3

2

Nominal shear force

Corrected shear force

Point A
Heavy ballast condition1

KC#459
Reference is made to KC #353 and to the supplement questions KC#453 submitted to IACS on 20
April 2007.
Q1 According to latest information available to us, we understood that the shear force correction may
be applied to each uneven loading condition according to [2.2.2] and thereby compared to theuncorrected shear force capacity curve according to [5.1.2]. The procedure is drawn up in items 1 to 3
below. Please review and confirm.
1.
Shear force capacity curve.
Qp according to [5.1.2] are drawn up based on direct shear force calculation as
given in [2.2.1]. Shear force capacity to be established based on direct calculation
meaning shear flow analysis. See figure 1. Please confirm.

Side thick

t1

t2

t1

t1

t1

t2

t1

t2

t1

Side
capacity.
Qp[5.1.2]
Figure 1 Shear force capacity according to [5.1.2]
2.

Approval verification.
Design loading conditions in the loading manual should be plotted with bothcorrected and uncorrected shear force. Corrected shear forces are comparedagainst Qp according to Ch.5 Sec.1 [5.1.2]. The correction is performed according
to [2.2.2] and performed for uneven loading conditions only. See figure 2. Pleaseconfirm.

Load cond

Hold 5

Hold 4

Hold 3

Shear force
Qp[5.1.2]
QSW,Nominal
QSW,Corrected
Figure 2 Strength check according to [2.2.2] and [5.1.2]
3.

In service verification with loading computer.
When the ship crew enters an uneven loading condition into the loading
instrument, the strength verification is performed similar to item 2 above.
That is, the loading computer computes the corrected shear force according
to [2.2.2] and compares the results with the Qp[5.1.2] according to the direct
approach. Please confirm.

Q2 If above iQ1 is confirmed the, definition of Qp is different between [5.1.2] and [5.1.3] regarding
application of shear force correction.
The Qp defined by [5.1.2] should be compared to “net shear forces” after shear force correction
applied to each uneven loading condition calculated by Loading Computer onboard. Same with suchconditions included in the Loading Manual.
Qp given in [5.1.3] includes shear force correction Delta-Qc which is absolutely “added” on top of thecapacity limit based on the given scantlings and allowable stress. We suppose the intention of Qp as
given in [5.1.3] is to make shear force correction unnecessary in each loading condition calculated by
the Loading Computer onboard. Please refer to figure 3 where the correction is made for one alternate
loading condition.

Shear force
corrected/
uncorrected

Shear force
Capacity
Qp,nominal

Corrected
shear force
capacity
curve Qp

'Q2
'Q1

'Q1

'Q1

'Q3

'Q4

'Q5

'Q2
'Q3

'Q4

'Q5

'Q2
'Q3

'Q4

Nominalshear force tobe within Qp

Figure 3 Shear force approach according to [5.1.3]
This has created some confusion and uncertainty of Qp as defined by [5.1.3] such as:
1)
Uncertainty of shear force correction Delta-Qc included in Qp when applied to a new loading
condition calculated by Loading Computer onboard.
2)
A few sets of Qp need to be established to deal with different uneven loading conditions
correctly.
3)
In case of flooding conditions, the above two issues 1) and 2) will be more confusing anddifficult to deal with.

To avoid any confusion and uncertainty, we therefore propose to take out Delta-Qc term from the Qp
formula given in [5.1.3] and instead add texts in both [5.1.2] and [5.1.3] to the effect; “shear force
correction as given in [2.2.2] should be applied to uneven loading conditions calculated by Loading
Computer onboard. Corrected shear forces are then compared against Qp.” Same applies to Qpf
formula in [5.3.3]. Please consider.
Q3 As discussed in above Q2, we assume that [5.1.3] does not apply if Qp is obtained by [5.1.2].
Similarly, [5.3.3] does not apply if Qpf is obtained by [5.3.2] for flooding cases.
Please confirm.
Q4 In this connection, we find it difficult to agree to the answer to Q3 of KC #353 where it is stated that“shear force correction should be done at the bulkhead where adjacent holds are in nonhomogeneous loading condition.” As we mentioned in Q2 submitted on 20 April 2007, the answer will
not correctly reflect the physics behind the shear force correction in case of heavy ballast condition.
Please see Point A in the attached illustration. This is more prominent in case of Capesize. Please reconsider.

KC#499

s/2

s

s
s/2

s
20tp

s/2

20tp
20tp

Hard Corners

Longitudinal
20tp

stiffened plate

20tp

20tp

Transversely
s/2

stiffened plate
s

s/2
s

KC#519
Question for ULS

Rule Ref.: Bulker CSR Ch5 Appendix 1, Tanker CSR Appendix A 2.3

Interpretation

requestedtocalculation

procedurefor

ultimate

strengthincremental-iterative approach.
ID

Questions

Q1

Shortening curve for a stiffened plate element

Figures

where material of plate and stiffener are different.

HT32

HT36
Q2

Shortening curve for an element where thickness ofplate are different. The element can be stiffener orplate.

Q3

t1

t2

t1
HT36

t2
HT32

Shortening curve for an element where material
and thickness of attached plate are different

byKC#520
Question for ULS

Rule Ref.: Bulker CSR Ch5 Appendix 1, Tanker CSR Appendix A 2.3

Interpretation

requestedtocalculation

procedurefor

ultimate

strengthincremental-iterative approach.
ID

Questions

Q1

For plates stiffened by not longitudinally continued

Figures

stiffeners such as girders in double bottom, how to
divide the plate to calculation elements. Should thestiffeners be neglected and considered as plateelements?

SnippedstiffenersbyKC#521
Question for ULS

Rule Ref.: Bulker CSR Ch5 Appendix 1, Tanker CSR Appendix A 2.3

Interpretation

requestedtocalculation

procedure

for

incremental-iterative approach.
ID

Questions

Q1

For stiffeners where one side of web are supported
by bracket which space less than the space ofprimary supporting members, which is length of
this element, space of brackets or supporting
members?

Figures

ultimate

strengthbyKC#634

CHAPTER 5 – HULL GIRDER STRENGTHAPPENDIX 1 HULL GIRDER ULTIMATE STRENGTH

2.

Criteria for the calculation of the curve M-F

2.2

Load-end shortening curve V-H

2.2.4

Beam column buckling

The equation describing the load-end shortening curve ıCR1-H for the beam column buckling of ordinary
stiffeners composing the hull girder transverse section is to be obtained from the following formula (see Fig 3):

V CR1

ĭsV C1s AStif  ĭ pV C1 p 10bE t p
AStif  10 st p

where:)s: Edge function defined in [2.2.3], for ordinary stiffener)p: Edge function defined in [2.2.3], for attached plate

ReHs: Minimum yield stress, in N/mm2, of the material of the stiffener

ReHp: Minimum yield stress, in N/mm2, of the material of attached plate

AStif: Net sectional area of the stiffener, in cm2, without attached plating

VC1s: Critical stress for the stiffener with its material of ReHs, in N/mm2, equal to:V C 1sV E1
Hs

for V E1 d

ReHs
Hs
2

V C 1s§ R H ·
ReHs ¨¨1  eHs s ¸¸
4 V E1 ¹©

for V E1 !

ReHs
Hs
2

Hs

: Relative strain of the material of the stiffener, equal to:



Hs

HYs

: Strain at yield stress of the material of the stiffener, equal to: H Ys
HE

HE
H Ys
ReHs
E

: Element strain

COMMON STRUCTURAL RULES FOR BULK CARRIERSCHAPTER 5, APPENDIX 1: Critical stress for the stiffener with the material of ReHp, in N/mm2, equal to:

VC1p

V C1 p

V E1
Hp

V C1 p§ R H ·
ReHp ¨¨1  eHp p ¸¸
4 V E1 ¹©

for V E1 d

for V E1 !

ReHp
2

ReHp
2

Hp

Hp

Hp

: Relative strain of the material of attached plate, equal to:



Hp

HYp

: Strain at yield stress of the material of attached plate, equal to: H Yp

HE
H Yp
ReHp
E

: Euler column buckling stress, in N/mm2, equal to:

VE1

V E1

S 2E

IE
AE l 210 4IE: Net moment of inertia of ordinary stiffeners, in cm4, with attached shell plating of width bE1

bE1: Effective width, in m, of the attached shell plating, equal to:
b E1

bE1

EE

103

s

EE
s

for E E ! 1.0
for E E d 1.0

s
HE
tp

AE

: Net sectional area, in cm2, of ordinary stiffeners with attached shell plating of width bE

bE: Effective width, in m, of the attached shell plating, equal to:bE§ 2.25 1.25 ·¨
 2 ¸s¨ E
E E ¸¹
E©

for E E ! 1.25

bE

sfor E E d 1.25

2.2.5 Torsional buckling
The equation describing the load-end shortening curve ıCR2-İ for the flexural-torsional buckling of ordinary
stiffeners composing the hull girder transverse section is to be obtained according to the following formula (seeFig 4).

V CR 2

ĭs AStif V C 2  ĭ p 10st pV CP
AStif  10st p

where:)s: Edge function defined in [2.2.4]

PAGE 2JANUARY 2006)p

: Edge function defined in [2.2.4]

AStif: Net sectional area of the stiffener, in cm2, without attached plating

ReHs: Minimum yield stress, in N/mm2, defined in [2.2.4]

ReHp: Minimum yield stress, in N/mm2, defined in [2.2.4]

Hs: Relative strain for the material of ordinary stiffener, defined in [2.2.4]

VC2: Critical stress, in N/mm2, equal to:

VC2

V E2
Hs

for V E 2 d

ReHs
Hs
2

VC2

§
R H ·
ReHs ¨¨1  eHs s ¸¸
4V E 2 ¹©

for V E 2 !

ReHs
Hs
2

VE2

: Euler torsional buckling stress, in N/mm2, defined in Ch 6, Sec 3, [4.3]

VCP: Buckling stress of the attached plating, in N/mm2, equal to:

EE

V CP

§ 2.25 1.25 ·¨¨
 2 ¸¸ ReHp
E
EE ¹
© E

for E E ! 1.25

V CP

ReHp

for E E d 1.25

: Coefficient defined in [2.2.4]

2.2.6 Web local buckling of ordinary stiffeners made of flanged profiles
The equation describing the load-end shortening curve ıCR3-H for the web local buckling of flanged ordinary
stiffeners composing the hull girder transverse section is to be obtained from the following formula:

V CR 3

ĭ p ReHp 103 bE t P  ĭs ReHs (hwet w  b f t f )103 st p  hwt w  b f t f

where:)s: Edge function defined in [2.2.4])p: Edge function defined in [2.2.4]

ReHs: Minimum yield stress, in N/mm2, defined in [2.2.4]

ReHp: Minimum yield stress, in N/mm2, defined in [2.2.4]

bE: Effective width, in m, of the attached shell plating, defined in [2.2.4]

hwe: Effective height, in mm, of the web, equal to:hwe(

2.25 1.25
 2 )hw

for E w ! 1.25

hwe

hw

for E w d 1.25

Ew

Ew

hw
HE
tw

HE

: Element strain

Ew

COMMON STRUCTURAL RULES FOR BULK CARRIERSCHAPTER 5, APPENDIX 1

2.2.7 Web local buckling of ordinary stiffeners made of flat bars
The equation describing the load-end shortening curve ıCR4-H for the web local buckling of flat bar ordinary
stiffeners composing the hull girder transverse section is to be obtained from the following formula (see Fig 5):

V CR 4

ĭ p 10 st PV CP  ĭs AStif V C 4
AStif  10st P

where:)s: Edge function defined in [2.2.4])p: Edge function defined in [2.2.4]

ReHs: Minimum yield stress, in N/mm2, defined in [2.2.4]

AStif: Net sectional area of the stiffener, in cm2, without attached plating

VCP: Buckling stress of the attached plating, in N/mm2, defined in [2.2.5]

VC4: Critical stress, in N/mm2, equal to:

VE4

VC4

V E4
Hs

for V E 4 d

ReHs
Hs
2

VC4

§ R H ·
ReHs ¨¨1  eHs s ¸¸
4V E 4 ¹©

for V E 4 !

ReHs
Hs
2

: Local Euler buckling stress, in N/mm2, equal to:

V E4

Hs

§t ·
160000¨¨ w ¸¸© hw ¹

2: Relative strain for the material of ordinary stiffener, defined in [2.2.4]

2.2.8 Plate buckling
The equation describing the load-end shortening curve ıCR5-İ for the buckling of transversely stiffened panels
composing the hull girder transverse section is to be obtained from the following formula:

V CR 5­ ReHp ĭ p°°2ª s § 2.25 1.25 ·min ®
1 · º
§ s ·§°ĭ p ReHp « " ¨¨ E  E 2 ¸¸  0.1¨1  " ¸¨¨1  E 2 ¸¸ »©
¹©
«¬ © E
E ¹
E ¹ »
°¯
¼

where:)p Edge function defined in [2.2.4].

ReHs: Minimum yield stress, in N/mm2, defined in [2.2.4]

EE: Coefficient defined in [2.2.4].

PAGE 4JANUARY 2006

KC#788
Item
Ch 1 Sec 4 [2.3] loads
Ch 4 Sec 3 [1.1.1][Definition][sign convention]

Still water (SW) shear force

Still water (SW)bending moment

DesignDesignVertical shear force

Vertical bending moment

Note

A term, ‘vertical’, is missing in thetitle of Figure1.

Ch 4 Sec 3 [2.1.1]{Still water loads}

Ch 4 Sec 3 [2.2][SW bending

moment]Shear force

Vertical SW bending moment

To be treated as the upper limit

To be treated as the upper limit

Design SW shear force:

Design SW bending moment:

Greater values may be considered if

Maximum shear force for the loading

Maximum SW bending moment for thedefined by the Designer.

Ch 4 Sec 3 [2.3][SW shear force]

conditionloading condition.

Ch 4 Sec 3 [2.4]{flooded condition}

SW shear force

SW bending moment

Ver. SF

Ver BM

Ch 4 Sec 4 Table 2
Ch 4 Sec 7 [1.2.4] & {1.2.5][Loading

Design loading conditions specified in

condition]
Ch 4 Sec 7 [4.2.1]

the loading manual
SW vertical shear force in Table 3

SW vertical bending moment in Table 2

A term, ‘vertical’, is missing in thetitle of 4.2.

Ch 4 Sec 7 [4.2.2]

If one loading condition in LM has a SW

Vertical shear force should also bevertical bending moment more severe

considered.

than the value in Table 2
Ch 4 Sec 7 Table 2 & Table 3

Allowable SW shear force

Allowable SW vertical bending moment

Ch 4 Sec 8 [2.1.1] (All ships)

Permissible limits of SW shear force

Permissible

Ch 4 Sec 8 [2.1.2] (flooding, L>150m)

limitsofSW

bending

Same term as stated in UR S1A.2.1.c).

momentSW shear forces do not exceed the

SW bending moments do not exceed thespecified permissible limits

specified permissible limits

Ch 4 Sec 8 [3.2.2]

Hull girder shear force limits

Hull girder bending moment limits

Ch 5 Sec 1 Symbol

Design SW shear force

Design SW bending moment

Ch 5 Sec 1 [1.1.1]

the criteria for calculating HG strength to be used for the checks 2 to 5, i.a.w. theHull girder strength estimation is

HG loads specified in Ch 4 Sec 3.

carried out with ‘Design loads’

Ch 4 Sec 8 [3.1.1] & [3.1.2]

Ch 5 Sec 1 [2.1] and [2.2]

Qsw: Design

Msw: DesignCh 5 Sec 1 [4]Msw: Design

Ch 5 Sec 1 [5.1.1]

Permissible SW bending moment is thePermissible value = Design value

value Msw (Design)
Ch 5 Sec 1 [5.1.2] Direct

Permissible SW shear force,

A lower value of the permissible SW

Ch 5 Sec 1 [5.1.3] Simplified

calculated based on allowable stressshear force may be considered, if
requested by the Shipbuilder.

Ch 5 Sec 1 [5.2.2] Simplified

Permissible SW shear force,(Harbour conditions)with reference to the value in [5.1.3].

Ch 5 Sec 1 [5.3.1]

Same as above

Permissible SW bending moment is

Permissible value = design value

Msw,F (Design)
Ch 5 Sec 1 [5.3.2] direct

Permissible SW shear force,

Ch 5 Sec 1 [5.3.㧟] Simplified

calculated based on allowable stress

Ch 5 Sec 2 and Appendix 1

Msw: Design SW bending moment

Ch 6 Sec 1 [3.1.5]

Msw: Permissible SW bending moment

Ch 6 Sec 2 [3.1.5]
Ch 6 Sec 4 [2.1.5]
Ch 6 Sec 3 [2.1.3]

Design SW shear force
If design SW shear force is notavailable, the following default value
may be used.

Ch 7 Sec 2 Symbol

Qsw: Allowable SW shear force

Msw; Design vertical bending moment

Terms, ‘Still Water’ are missing in thedefinition of Msw.

Ch 7 Sec 2 [2.5.2] and [2.5.3]
Ch 8 Sec 3 [3.2.2] & Sec 4 [3.2.2]

Maximum vertical shear force

Maximum vertical bending moment
SW vertical bending moment in Ch 4

Hull girder strength estimation is

Sec 3 [2.2], If the design value is not

carried out with ‘Design loads’

available, the permissible value isobtained by the following formula