Common Structural Rules for
Bulk Carriers, January 2006

Background Document
CHAPTER 3 – STRUCTURAL DESIGN PRINCIPLES

NOTE:- This TB is published to improve the transparency of CSRs and increase theunderstanding of CSRs in the industry.
- The content of the TB is not to be considered as requirements.
- This TB cannot be used to avoid any requirements in CSRs, and in cases
where this TB deviates from the Rules, the Rules have precedence.
- This TB provides the background for the first version (January 2006) of theCSRs, and is not subject to maintenance.

COMMON STRUCTURAL RULES FOR BULK CARRIERS − BACKGROUND DOCUMENT
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COMMON STRUCTURAL RULES FOR BULK CARRIERSCOMMON STRUCTURAL RULES FOR BULK CARRIERS − BACKGROUND DOCUMENT
PAGE 3 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLESTABLE OF CONTENTS:
SECTION 1 – MATERIALS................................................................................................................. 6
1.

GENERAL.................................................................................................................................... 6
1.1
1.2
1.3

2.

HULL STRUCTURAL STEEL...................................................................................................... 6
2.1
2.2
2.3
2.4

3.

General .................................................................................................................................... 8
Steels for forging ..................................................................................................................... 9
Steels for casting...................................................................................................................... 9

ALUMINIUM ALLOY STRUCTURES........................................................................................ 9
4.1
4.2
4.3
4.4

5.

General .................................................................................................................................... 6
Material factor k....................................................................................................................... 7
Grades of steel ......................................................................................................................... 7
Structures exposed to low air temperature ............................................................................. 8

STEELS FOR FORGING AND CASTING.................................................................................. 8
3.1
3.2
3.3

4.

Standard of material................................................................................................................ 6
Testing of materials ................................................................................................................. 6
Manufacturing processes ........................................................................................................ 6

General .................................................................................................................................... 9
Extruded plating ..................................................................................................................... 9
Mechanical propertied of weld joints.................................................................................... 10
Material factor k..................................................................................................................... 10

OTHER MATERIALS AND PRODUCTS................................................................................. 10
5.1
5.2

General .................................................................................................................................. 10
Iron cast parts ........................................................................................................................ 10

SECTION 2 – NET SCANTLING APPROACH ................................................................................ 111.

GENERAL PHILOSOPHY......................................................................................................... 11
1.1 ...................................................................................................................................................... 112.

APPLICATION CRITERIA ....................................................................................................... 11
2.1

3.

General .................................................................................................................................. 11

NET SCANTLING APPROACH ............................................................................................... 11
3.1
3.2
3.3

Net scantling definition ........................................................................................................ 11
Considered net scantling....................................................................................................... 12
Available information on structural drawings...................................................................... 14

SECTION 3 – CORROSION ADDITIONS....................................................................................... 15
1.

CORROSION ADDITIONS...................................................................................................... 15
1.1
1.2

General .................................................................................................................................. 15
Corrosion addition determination........................................................................................ 15

SECTION 4 – LIMIT STATES ........................................................................................................... 16
1.

GENERAL.................................................................................................................................. 16
1.1
1.2

2.

General principle................................................................................................................... 16
Limit states ............................................................................................................................ 16

STRENGTH CRITERIA ............................................................................................................ 16
2.1

Serviceability limit states....................................................................................................... 16

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PAGE 4 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLES

2.2
2.3
2.4
3.

Ultimate limit state ................................................................................................................ 17
Fatigue limit state .................................................................................................................. 17
Accidental limit state ............................................................................................................. 17

STRENGTH CHECK AGAINST IMPACT LOADS ................................................................. 18
3.1

General .................................................................................................................................. 18

SECTION 5 – MEASURES AGAINST CORROSION ...................................................................... 191.

GENERAL.................................................................................................................................. 19
1.1
1.2
1.3
1.4

2.

SACRIFICIAL ANODES ........................................................................................................... 20
2.1

3.

Structures to be protected...................................................................................................... 19
Protection of seawater ballast tanks and void double side skin spaces................................. 19
Protection of cargo hold spaces ............................................................................................. 20
Protection of ballast hold spaces............................................................................................ 20
General .................................................................................................................................. 20

PROTECTION OF INNER BOTTOM PLATING BY CEILING ............................................... 20
3.1
3.2
3.3

General .................................................................................................................................. 20
Arrangement ......................................................................................................................... 20
Scantlings............................................................................................................................... 21

SECTION 6 – STRUCTURAL ARRANGEMENT PRINCIPLES ...................................................... 22
1.

APPLICATION .......................................................................................................................... 22
1.1 ...................................................................................................................................................... 222.

GENERAL PRINCIPLES ........................................................................................................... 22
2.1
2.2
2.3

3.

PLATING................................................................................................................................... 23
3.1

4.

Profile of stiffeners................................................................................................................. 23
Span of ordinary stiffener...................................................................................................... 23
Attached plating .................................................................................................................... 24
Geometric property of ordinary stiffeners............................................................................. 24
End connections of ordinary stiffeners.................................................................................. 24

PRIMARY SUPPORTING MEMBERS...................................................................................... 25
5.1
5.2
5.3
5.4
5.5
5.6
5.7

6.

Structural continuity of plating ............................................................................................. 23

ORDINARY STIFFENER........................................................................................................... 23
4.1
4.2
4.3
4.4
4.5

5.

Definition............................................................................................................................... 22
Structural continuity.............................................................................................................. 22
Connections with higher tensile steel .................................................................................... 23

General .................................................................................................................................. 25
Stiffening arrangement .......................................................................................................... 25
Span of primary supporting members .................................................................................. 25
Effective breadth of primary supporting member................................................................. 26
Geometric properties ............................................................................................................. 26
Bracketed end connection...................................................................................................... 26
Cut-outs and holes................................................................................................................. 26

DOUBLE BOTTOM................................................................................................................... 27
6.1
6.2
6.3

General .................................................................................................................................. 27
Keel........................................................................................................................................ 28
Girders................................................................................................................................... 28

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6.4
6.5

Floors..................................................................................................................................... 28
Bilge strake and bilge keel..................................................................................................... 28

DOUBLE SIDE STRUCTURE ................................................................................................... 29

7.

7.1
7.2
7.3
7.4
7.5

Application............................................................................................................................ 29
Design principles................................................................................................................... 29
Structural arrangement ......................................................................................................... 29
Longitudinally framed double side....................................................................................... 30
Transversely framed double side .......................................................................................... 30

SINGLE SIDE STRUCTURE ..................................................................................................... 30

8.

8.1
8.2
8.3
8.4
8.5
8.6

Application............................................................................................................................ 30
General arrangement............................................................................................................. 30
Side frames ............................................................................................................................ 30
Upper and lower brackets ..................................................................................................... 30
Tripping brackets .................................................................................................................. 31
Support structure .................................................................................................................. 31

DECK STRUCTURE .................................................................................................................. 31

9.

9.1
9.2
9.3
9.4
9.5
9.6
10.
10.1
10.2
10.3
10.4
10.5
10.6
11.
11.1

Application............................................................................................................................ 31
General arrangement............................................................................................................. 31
Longitudinally framed deck.................................................................................................. 32
Transversely framed deck ..................................................................................................... 32
Hatch supporting structures ................................................................................................. 33
Openings in the strength deck .............................................................................................. 33
BULKHEAD STRUCTURE.................................................................................................... 33
Application............................................................................................................................ 33
General .................................................................................................................................. 33
Plane bulkheads .................................................................................................................... 34
Corrugated bulkheads........................................................................................................... 34
Non-tight bulkheads ............................................................................................................. 35
Watertight bulkheads of trunks and tunnels......................................................................... 36
PILLARS ................................................................................................................................ 36
General .................................................................................................................................. 36

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PAGE 6 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLESSECTION 1 – MATERIALS
1. GENERAL
1.1

Standard of material

1.1.1
1.1.1.aSince regulations related to material standards, material tests, and manufacturingmethods exist in the rules of every classification society, general regulations havebeen specified to refer to them.

1.1.2
1.1.2.a

1.2

Since regulations related to material standards, material tests, and manufacturingmethods exist in the rules of every classification society, general regulations havebeen specified to refer to them.

Testing of materials

1.2.1
1.2.1.a

1.3

Since regulations related to material standards, material tests, and manufacturingmethods exist in the rules of every classification society, general regulations havebeen specified to refer to them.

Manufacturing processes

1.3.1
1.3.1.aSince regulations related to material standards, material tests, and manufacturingmethods exist in the rules of every classification society, general regulations havebeen specified to refer to them.

2. HULL STRUCTURAL STEEL
2.1

General

2.1.1
2.1.1.aThis regulation is in accordance with IACS UR W11.

2.1.2
2.1.2.aThis regulation is in accordance with IACS UR W11.

2.1.3
2.1.3.aThis regulation is in accordance with IACS UR W11.

2.1.4
2.1.4.aThis regulation is in accordance with IACS UR W11.

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PAGE 7 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLES

2.1.5
2.1.5.a2.2

This regulation is in accordance with IACS UR W11.

Material factor k

2.2.1
2.2.1.a

2.3

Material factor specified in 2.2 is arrived at by including the material factor of HT40,
0.68, specified in the regulation IACS UR S4. The material factor of HT40 has been
established based on the existing treatment in each classification society, and istherefore consistent with the value in Part CSR-T.

Grades of steel

2.3.1
2.3.1.aRegulations related to steel grades specified in 2.3, 2.4, and usage categories ofmaterials are the same as in IACS UR S6. CSR evaluates structural dimensions
based on the net scantling approach, but the usage categories of steel are based on
the gross scantlings (scantlings in drawings).
There is a requirement in Reg. 6.5.3, Chapter XII of the SOLAS Convention and its
interpretation in Clause 4.2 of SLS. 14 Circ. 250 that states, "If the damage is a crack
in the weld, its instantaneous propagation should be avoided. This should be
realized by appropriate design and selection of material." To comply with thisrequirement, CSR has usage categories of material as in Table 4 in the rules. For BCA and BC-B ships complying with Reg. 6.5.3, Chapter 12 of the SOLAS Convention,
the material at locations in the range of 0.125 times the span of hold frames aboveand below the point of intersection of the hold frame lower bracket, side shell
plating and bilge hopper slant plate in single side skin structure is required to behigher than grade D/DH.

2.3.2
2.3.2.aThis regulation is in accordance with IACS UR S6.1.

2.3.3
2.3.3.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, Note 2 of Table 3.

2.3.4
2.3.4.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, Note 3 of Table 3.

2.3.5
2.3.5.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 2.4.4.

2.3.6
2.3.6.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 2.4.5.

2.3.7
2.3.7.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 2.4.6.

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2.3.8
2.3.8.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 2.4.7.

2.3.9
2.3.9.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 2.4.8.

2.3.102.3.10.a This regulation is based on BV Rules Part B Chapter 4 Section 1, 2.4.9.

2.3.11
2.3.11.a This regulation is based on BV Rules Part B Chapter 4 Section 1, 2.4.10.

2.4Structures exposed to low air temperature

2.4.1
2.4.1.a

It is considered that for this topic, no information in addition to that shown in theRules is necessary to explain the background.

2.4.2
2.4.2.aThis regulation is in accordance with IACS UR S6.2.

2.4.3
2.4.3.aThis regulation is in accordance with IACS UR S6.2.

2.4.4
2.4.4.aThis regulation is in accordance with IACS UR S6.2.

2.4.5
2.4.5.aThis regulation is in accordance with IACS UR S6.2.

2.4.6
2.4.6.aThis regulation is in accordance with IACS UR S6.2.

3. STEELS FOR FORGING AND CASTING
3.1

General

3.1.1
3.1.1.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 3.1.1.

3.1.2
3.1.2.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 3.1.2.

3.1.3
3.1.3.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 3.1.3.

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3.2

Steels for forging

3.2.1
3.2.1.a

3.3This regulation is based on BV Rules Part B Chapter 4 Section 1, 3.2.2.

Steels for casting

3.3.1
3.3.1.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 3.3.1.

3.3.2
3.3.2.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 3.3.3.

3.3.3
3.3.3.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 3.3.4.

4. ALUMINIUM ALLOY STRUCTURES
4.1

General

4.1.1
4.1.1.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 4.1.1.

4.1.2
4.1.2.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 4.1.2.

4.1.3
4.1.3.a

4.2

This regulation is based on BV Rules Part B Chapter 4 Section 1, 4.1.3.

Extruded plating

4.2.1
4.2.1.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 4.2.1.

4.2.2
4.2.2.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 4.2.2.

4.2.3
4.2.3.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 4.2.3.

4.2.4
4.2.4.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 4.2.4.

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4.3

Mechanical propertied of weld joints

4.3.1
4.3.1.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 4.3.1.

4.3.2
4.3.2.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 4.3.2.

4.3.3
4.3.3.a

4.4This regulation is based on BV Rules Part B Chapter 4 Section 1, 4.3.3.

Material factor k

4.4.1
4.4.1.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 4.4.1.

4.4.2
4.4.2.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 4.4.2.

5. OTHER MATERIALS AND PRODUCTS
5.1

General

5.1.1
5.1.1.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 5.1.1.

5.1.2
5.1.2.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 5.1.2.

5.1.3
5.1.3.a

5.2

This regulation is based on BV Rules Part B Chapter 4 Section 1, 5.1.3.

Iron cast parts

5.2.1
5.2.1.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 5.2.1.

5.2.2
5.2.2.aThis regulation is based on BV Rules Part B Chapter 4 Section 1, 5.2.2.

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PAGE 11 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLESSECTION 2 – NET SCANTLING APPROACH
1. GENERAL PHILOSOPHY
1.1
1.1.1
1.1.1.aThis regulation gives the concept of the net scantling approach. In CSR for Bulk
Carriers, similar to CSR for Tankers, all strength regulations including those forfatigue strength assessment are based on the net scantling approach.

2. APPLICATION CRITERIA
2.1

General

2.1.1
2.1.1.aThe structural scantlings in the Rules are based on the net scantling approach, but
for massive structures such as superstructure, deck house, rudder structure, andmassive pieces of forgings and castings, the scantlings of which are decided byempirical formulae, one cannot distinguish clearly the scantlings according tostrength and the scantlings according to corrosion and thickness diminution;
therefore, the non-application of the net scantling approach has been noted in 2.1.1.

2.1.2
2.1.2.aThis regulation describes the strength properties for which the net scantling
approach is applicable.

2.1.3
2.1.3.aThis regulation shows that the as-built scantlings are greater than the required grossscantlings. If addition in plating thickness is requested by the shipowner, the asbuilt scantlings will include this addition. The required gross scantling is thescantling obtained by adding the corrosion addition specified in Section 3, Chapter
3 to the required net scantling, as described in the explanations on notations. The
corrosion addition is in 0.5-mm units, but the required net scantlings are not in 0.5mm units. To round off the required net scantlings to 0.5-mm units, the method
adopted was to round off to one decimal digit by discarding the second decimal
digit if its value is 2 and below, and adding 1 to the first digit if the value of thesecond digit is 3 and above. This method is consistent with the method used in CSR
for Tankers.

3. NET SCANTLING APPROACH
3.1

Net scantling definition

3.1.1

Required thickness

3.1.1.aDefinition of required thickness is specified.
This regulation has been set to define the net scantling approach. Net scantlings canbe broadly divided into two parts as follows:
COMMON STRUCTURAL RULES FOR BULK CARRIERSCOMMON STRUCTURAL RULES FOR BULK CARRIERS − BACKGROUND DOCUMENT
PAGE 12 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLES(a) Required thickness determined from rule formulae(b) Scantling that determines the structural properties, such as section properties
from rule formulae, or thickness assessed from direct strength calculations,longitudinal bending strength, or fatigue strength assessment.
The irem (a) mentioned above was defined as the required net scantling, while theitem (b) mentioned above was defined as the offered net scantling, and theapplicable method of corrosion addition for each case was clearly defined.

3.1.2

Offered thickness

3.1.2.aDefinition of offered thickness is specified.

3.1.3

Net thickness for plate

3.1.3.aDefinition of net thickness for plate (net thickness offered) is specified.

3.1.4

Net section modulus for stiffener

3.1.4.aThis regulation is a clarification of net section modulus for stiffener.

3.2

Considered net scantling

3.2.1

Yielding check of the hull girder

3.2.1.a

The regulations of 3.2 show the application of corrosion addition for each strength
assessment. A summary of the application of corrosion addition is shown in Table
3.2.1.
Table 3.2.1

Application of corrosion addition
Corrosion
addition

HG stresst corr

0.5t corr

t corr

0.5t corr

Stress assessment
FEA
Primary supporting members
Buckling assessmentof ships above 150 m
Minimum thickness

0.5t corr

0.5t corr

t corrt corr

0.5t corr

Section characteristic

0.5t corr

Buckling

t corr

0.5t corr

0.5t corr

0.5t corr

0.5t corr
0.5t corr
0.5t corr

0.5t corr
0.5t corr
0.5t corr

Local members and primary Thickness (including
supporting members of ships minimum thickness)below 150 m (rule formula)
Section characteristic

Hull Girder
Hull girder ultimate strength

Stiffener
Fatigue strength

FEA

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PAGE 13 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLES

For assessment of overall strength by the direct strength calculation or assessmentof hull girder strength, the assumption that the thickness of all structural members
to be assessed reduces to the permissible wastage amount is an assumption on theside of excessive safety. Considering the variation in the corrosion phenomenon,
reduction in thickness to the average wastage amount may be assumed, but half thecorrosion addition may be considered as the average wastage amount. In assessing
the buckling strength of stiffeners or panels, stresses acting on the stiffeners or
panels are used assuming that complete structures are in a fully corroded state on
the average. On the other hand, since critical buckling stresses in stiffeners or panels
are for local structures, these structures are assumed to be in a fully corroded stateof 100% of corrosion addition for assessment on the side of safety.
Repetitive loads encountered within the assumed service period were considered
for fatigue strength assessment. Assessment is difficult for the elapsed period fromthe time of a new ship when the members to be assessed are not corroded at all,until the members to be assessed are in the wasted condition with the corrosion
amount assumed for the assumed service period. It was therefore decided toassume an average corrosion and reduced thickness condition that occur during theassumed service period. In the application of average corrosion amount in thefatigue strength assessment, since corrosion is ignored during the period thepainting is effective, the assessment is very much on the safe side. As a conclusion,
two corrosion models are considered; that is 100% corrosion additions are taken forthe local scantling formulae and buckling capacity assessment and 50% corrosion
additions are taken for Hull girder check, FEA and Fatigue check.

3.2.2

Global stress such as stress due to hull girder bending moment and shear
force

3.2.2.a

The regulations of 3.2 show the application of corrosion addition for each strength
assessment. A summary of the application of corrosion addition is shown in Table
3.2.1.

3.2.3

Buckling check of the hull girder

3.2.3.a

The regulations of 3.2 show the application of corrosion addition for each strength
assessment. A summary of the application of corrosion addition is shown in Table
3.2.1.

3.2.4

Ultimate strength check of the hull girder

3.2.4.a

The regulations of 3.2 show the application of corrosion addition for each strength
assessment. A summary of the application of corrosion addition is shown in Table
3.2.1.

3.2.5

Direct strength analysis

3.2.5.a

The regulations of 3.2 show the application of corrosion addition for each strength
assessment. A summary of the application of corrosion addition is shown in Table
3.2.1.

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PAGE 14 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLES

3.2.6

Fatigue check3.2.6.a

The regulations of 3.2 show the application of corrosion addition for each strength
assessment. A summary of the application of corrosion addition is shown in Table
3.2.1.

3.2.7

Check of primary supporting members for ships less than 150m in length L

3.2.7.a

The regulations of 3.2 show the application of corrosion addition for each strength
assessment. A summary of the application of corrosion addition is shown in Table
3.2.1.

3.3

Available information on structural drawings

3.3.1
3.3.1.a

The net scantling approach signifies thicknesses that become renewal criteria when
the net scantling approach is applied. Accordingly, as-built thicknesses and renewal
criteria should be stated in the structural drawings. If additional thicknesses
requested by the shipowner exist, they should also be clearly specified on thedrawings.

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PAGE 15 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLESSECTION 3 – CORROSION ADDITIONS
1. CORROSION ADDITIONS
1.1

General

1.1.1
1.1.1.aCorrosion addition was set as the estimated value of corrosion amount in a 25-year
period from progressive corrosion models based on the probabilistic theory andthickness measurement data of several hundred thousands of points. Regulations
associating corrosion addition with painting requirements were set since members
in ballast tank and cargo holds were required to be painted effectively. Since nodata on steels other than carbon steel (general steel) exists, separate considerations
are required for setting the corrosion addition.

1.2

Corrosion addition determination

1.2.1

Corrosion additions for steel

1.2.1.a

The corrosion addition largely depends on the corrosive environment to which thesteel is exposed. The factors for corrosive environment were analyzed and theirresults were summarized in Table 1 of the Rules. Corrosion addition for eachstructural member, particularly those that form the boundaries of compartments, isto be determined after considering the application to each side of the compartment.
The corrosion amount for each factor of the corrosive environment is in 0.1-mm
units. However, considering the relationship of the corrosion amount with therenewal criteria and that the nominal thickness of steel is generally in 0.5-mm units,
the value obtained by adding the value of the corrosive environment on one side tothat of the other side is rounded up to 0.5-mm units, and to this value, the maximum
value of corrosion amount estimated to progress during the survey interval (2.5
years) of 0.5 mm is added to arrive at the value of corrosion addition.
Regarding the application of corrosion addition, if a plate is subjected to multiple
corrosion additions, the maximum corrosion addition of the plate will be applied.

1.2.2

Corrosion addition for aluminum alloys

1.2.2.a

The Rules of each classification society require the use of corrosion-resistantaluminum alloys, in principle. Since the corrosion addition is taken as 0 mm in theseRules, CSR for Bulk Carriers has also followed the same provision.

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PAGE 16 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLESSECTION 4 – LIMIT STATES
1. GENERAL
1.1

General principle

1.1.1
1.1.1.a

The hull structure was classified into local structures considering local loads such asplates and stiffeners, primary supporting structures taking up loads on structural
bodies such as girders, and the hull girder in which the entire hull structure istreated as a beam, for studying the strength characteristics to be assessed in CSR.
The structural assessment items required for each structural category are shown in
Table 1 in the rules.

1.1.2
1.1.2.aStrength characteristics are specified not only for the intact condition but also forassessing strength in the damaged condition (flooded condition that occurs as aresult of damage).

1.2

Limit states

1.2.1

Serviceability limit state

1.2.1.aThis regulation defines the limit states such that the definitions coincide with thosein ISO 2394.

1.2.2

Ultimate limit state

1.2.2.aThis regulation defines the limit states such that the definitions coincide with thosein ISO 2394.

1.2.3

Fatigue limit state

1.2.3.aThis regulation defines the limit states such that the definitions coincide with thosein ISO 2394.

1.2.4

Accidental limit state

1.2.4.aThis regulation defines the limit states such that the definitions coincide with thosein ISO 2394. The flooded condition is considered as accidental limit states like IACS
UR S17, S18 and S20.

2. STRENGTH CRITERIA
2.1

Serviceability limit states

2.1.1

Hull girder

2.1.1.aThis regulation gives the load level for the yielding check of the hull girder
corresponding to the serviceability limit state. The strength criterion is based on theworking stress design method for the stress obtained by the beam theory. Thisphilosophy is the same of IACS UR S11.

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2.1.2

Plating

2.1.2.aThis regulation gives the load level for the yielding and buckling strength check for
platings constituting primary supporting members corresponding to theserviceability limit state. The stress of platings constituting primary supporting
members are obtained by the Finite Element Analysis based on the elastic theory.
The strength criterion is based on the working stress design method.

2.1.3

Ordinary stiffener

2.1.3.aThis regulation gives the load level for the strength check for ordinary stiffenercorresponding to the serviceability limit state. The strength criterion is based on theworking stress design method for the stress of ordinary stiffeners obtained by thebeam theory.

2.2

Ultimate limit state

2.2.1

Hull girder

2.2.1.aThis regulation gives the load level for the ultimate strength check of the hull girder
corresponding to the ultimate limit state. The strength criterion is based on thepartial safety factor design method.

2.2.2

Plating

2.2.2.aThis regulation gives the load level for the ultimate strength check of the platingscorresponding to the ultimate limit state. The strength criterion is based on theworking stress design method.

2.2.3

Ordinary stiffener

2.2.3.aThis regulation gives the load level for the ultimate strength check of the ordinary
stiffener corresponding to the ultimate limit state. This strength check is included in
the buckling check of stiffeners.

2.3

Fatigue limit state

2.3.1

Structural details

2.3.1.a

Fatigue strength of structural details such as connections of ordinary stiffeners andprimary supporting members is assessed based on the linear cumulative fatigue
damage procedure considering the cyclic loads during ship’s life. This regulation
gives the reference loads level for fatigue strength check.

2.4

Accidental limit state

2.4.1

Hull girder

2.4.1.a

Refer to 1.2.4a.

2.4.2

Double bottom structure

2.4.2.a

Refer to 1.2.4a.

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2.4.3

Bulkhead structure

2.4.3.a

Refer to 1.2.4a.

3. STRENGTH CHECK AGAINST IMPACT LOADS
3.1

General

3.1.1
3.1.1.a

Impact loads differ from general wave loads, and it is difficult to debate the load
level of an impact load. This regulation has been specified for general items, while
only the concepts of strength criteria used in the Rules have been given in 3.1.2.

3.1.2
3.1.2.aThis regulation has been specified for the concepts of strength criteria used in theRules.

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PAGE 19 – CHAPTER 3: STRUCTURAL DESIGN PRINCIPLESSECTION 5 – MEASURES AGAINST CORROSION
1. GENERAL
1.1

Structures to be protected

1.1.1
1.1.1.aRegulations for structures to be protected against corrosion are clearly specified
based on the regulations of Chapter XII of the SOLAS Convention and the existing
rules.

1.1.2
1.1.2.aRegulations for structures to be protected against corrosion are clearly specified
based on the regulations of Chapter XII of the SOLAS Convention and the existing
rules.

1.1.3
1.1.3.aIn the existing rules, only the locations where paint is to be applied have been
specified. Thus, compartments carrying fuel oil and narrow compartments not
mentioned herein are subject to treatment similar to the existing rules. Narrowcompartments can be filled generally with dry air.

1.1.4
1.1.4.a

1.2

In the existing rules, only the locations where paint is to be applied have been
specified. Thus, compartments carrying fuel oil and narrow compartments not
mentioned herein are subject to treatment similar to the existing rules. Narrowcompartments can be filled generally with dry air.

Protection of seawater ballast tanks and void double side skin spaces

1.2.1
1.2.1.a

The regulation of IACS UR Z8 has been adopted as-is. Although "bright color" is arecommendation for the color of paint in the existing regulation, considering thatpaints have been applied to facilitate surveys, to facilitate detection of fatigue
damage, and to have adequate anti-corrosive properties, and considering that shipsthat apply the Rules regulations because of these maintenance reasons are safer, thisregulation was made a mandatory requirement in Rules.

1.2.2
1.2.2.a

The "Performance Standard for Protective Coatings for ballast tanks and void
spaces" that has been discussed at the IMO, was incorporated because of the strong
demands of the shipowners. This matter was approved at the MO MSC81 meeting
held in May 2006, and is scheduled to be adopted at the MSC82 meeting to be heldin December 2006. When this requirement is adopted by the IMO, it will become
applicable to ships contracted to be built on or after that date, earlier than theapplicable date in the IMO.

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1.3

Protection of cargo hold spaces

1.3.1

Coating

1.3.1.aThis regulation is in accordance with IACS UR Z9.

1.3.2

Application

1.3.2.aThis regulation is in accordance with IACS UR Z9.

1.3.3

Side areas to be coated

1.3.3.aThis regulation is in accordance with IACS UR Z9.

1.3.4

Transverse bulkhead areas to be coated

1.3.4.aThis regulation is in accordance with IACS UR Z9.

1.4

Protection of ballast hold spaces

1.4.1

Application

1.4.1.aThis regulation is in accordance with IACS UR Z9.

2. SACRIFICIAL ANODES
2.1

General

2.1.1
2.1.1.aThis regulation is in accordance with IACS UR F1.

2.1.2
2.1.2.aThis regulation is in accordance with IACS UR F1.

2.1.3
2.1.3.aThis regulation is in accordance with IACS UR F1.

3. PROTECTION OF INNER BOTTOM PLATING BY CEILING
3.1

General

3.1.1
3.1.1.a

3.2

This regulation is based on BV Rules Part B Chapter 11 Section 1, 4, including apartial modification.

Arrangement

3.2.1
3.2.1.aThis regulation is based on BV Rules Part B Chapter 11 Section 1, 4.2.1, including apartial modification.

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3.2.2
3.2.2.aThis regulation is based on BV Rules Part B Chapter 11 Section 1, 4.2.2, including apartial modification.

3.2.3
3.2.3.aThis regulation is based on BV Rules Part B Chapter 11 Section 1, 4.2.3, including apartial modification.

3.2.4
3.2.4.a

3.3This regulation is based on BV Rules Part B Chapter 11 Section 1, 4.2.4, including apartial modification.

Scantlings

3.3.1
3.3.1.aThis regulation is based on BV Rules Part B Chapter 11 Section 1, 4.3.1, including apartial modification.

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1. APPLICATION
1.1
1.1.1
1.1.1.aRegulations have been established mainly for application of requirements forstructural arrangement in cargo spaces. Structural arrangement and scantling
requirements of forward and aft end parts are separately specified in Chapter 9 of
the Rules.

2. GENERAL PRINCIPLES
2.1

Definition

2.1.1
2.1.1.aThe spacing of primary supporting members and longitudinal stiffeners has been
defined. Here, secondary stiffeners are assumed in principle, as "ordinary stiffeners"
and stiffeners fitted to prevent buckling of webs of girders are not included.

2.2

Structural continuity

2.2.1

General2.2.1.a

General regulations related to continuity of longitudinal strength members are
specified in 2.2.2 to 2.2.4.

2.2.2

Longitudinal members

2.2.2.a

General regulations related to longitudinal members are specified.

2.2.3

Primary supporting members

2.2.3.a

General regulations related to primary supporting members are specified.

2.2.4

Ordinary stiffeners

2.2.4.a

General regulations related to ordinary stiffeners are specified.

2.2.5

Platings

2.2.5.a

When connecting plates of different thicknesses, the regulation of not permitting
difference in thickness greater than 50% of the thickness of the thicker plate wasspecified as a practical measure. If the difference in thickness is greater than 50%,an intermediate plate has to be inserted, and the thicker plate is to be tapered to thethickness of the thinner plate to maintain continuity.

2.2.6

Stress concentrations

2.2.6.aRegulations for avoiding locations of structural stress concentration andarrangement of openings were specified referring to the regulations of various
classification societies.
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2.3

Connections with higher tensile steel

2.3.1

Connections with higher tensile steel

2.3.1.a

Precautions for treatment of connections of high tensile steel members to structuralmembers of lower strength were established referring to the regulations of various
classification societies. Members fitted to deck or bottom shell such as bilge keel andhatch-side coaming are not installed as longitudinal strength members. However,since they are subjected to longitudinal bending effects, they are required to be ofmaterials with the same strength as the materials of the deck and bottom shell.
When stiffeners not continuous in the longitudinal direction are connected togirders installed as hatch coamings or longitudinal strength members such as
stiffeners sniped at both ends and fitted to prevent buckling, the material of thestiffeners should have the same strength as the member to which they are fitted.

3. PLATING
3.1

Structural continuity of plating

3.1.1

Insert plate

3.1.1.aThis regulation specifies ensuring the continuity of structure in case of difference inthickness of plating. Local reinforcement, such as the reinforcement around theopening has not been specified, but the requirement used conventionally andapproved by classification societies may be used.

4. ORDINARY STIFFENER
4.1

Profile of stiffeners

4.1.1

Stiffener profile with a bulb section

4.1.1.aSince plating with bulb section is treated as equivalent section, the simplified
formulae that give the equivalent section modulus, section area, and so on wereincorporated from 3.1.2, Sec. 3, Chapter 4, Part B of the BV Rules.

4.2

Span of ordinary stiffener

4.2.1

Ordinary stiffeners

4.2.1.a

The effective span of stiffener varies for the case where the primary structuralmember (face plate) is regarded as one plate flange while the primary supporting
member (web plate) is regarded as two plates flanges like a double bottom structure.
This regulation specifies the treatment of spans of such stiffeners. Moreover, thisspan is common to the assessment of bending strength and shear strength ofstiffeners.
For the treatment of struts between primary supporting members (floors) in a
double bottom structure, the regulation of 3.2.2, Sec. 3, Chapter 4, Part B of the BV
Rules has been incorporated. For installing a strut, the demands of shipowners has
been considered, and provision of struts is not approved in ships of length 120 m
and greater.

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4.2.2

Ordinary stiffener within a double hull

4.2.2.aTreatment of span of ordinary stiffener within a double hull is specified.

4.2.3

Ordinary stiffeners supported by struts

4.2.3.aTreatment of span of ordinary stiffener supported by struts is specified.

4.3

Attached plating

4.3.1

Effective breadth for yielding check4.3.1.a

To assess the bending strength of stiffeners, the sectional characteristics of stiffeners
should be assessed. In this case, the effective width of the plating attached to thestiffener needs to be considered. The regulation of 1.1.13-3, Part C of NK Rules,
which gives a simple index based on Shade's theory, is adopted for the effective
width of plating.

4.3.2

Effective width for buckling check4.3.2.a

The regulation for buckling strength of the Rules is based on the GL Rules. The
effective width for buckling strength assessment is also specified based on GL Rules.

4.4

Geometric property of ordinary stiffeners

4.4.1

General4.4.1.aSince CSR has incorporated the net scantling approach, the strength characteristics
of stiffener such as moment of inertia of section, section modulus, shear area,
slenderness ratio of web also correspond to the net scantling approach. Therefore,
the scantling obtained after deducting the corrosion addition from the offeredscantling (scantling in the drawing) of stiffener will be used for assessment.

4.4.2

Stiffener not perpendicular to the attached plating

4.4.2.a

When the stiffener is fitted not perpendicular to the plating such as shell plating,and if the angle between the stiffener and the plating is greater than 75 degrees, thedifference in the section modulus when the stiffener is fitted perpendicular to theplating is small. Therefore, the section characteristics may be assumed as thosewhen the stiffener is perpendicular. If the angle is between 50 degrees and 75
degrees, the requirement is that the angle should be considered and the section
characteristics corrected. If the angle is less than 50 degrees, a tripping bracket isrequired to be provided. Although not specified, if the angle between the stiffener
and the plating is less than 50 degrees, the section modulus of the stiffener will beaccording to direct strength calculation.

4.5

End connections of ordinary stiffeners

4.5.1

General4.5.1.aSlots are provided in the primary structural members to allow the stiffener to passthrough the primary supporting members. In this case, end fixation examples
according to 3.5, Sec. 3, Chapter 4, Part B of the BV Rules are shown.

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4.5.2

Structural continuity of stiffeners

4.5.2.aThis regulation has been specified referring to the regulation in 3.5.2, Sec. 3, Chapter
4, Part B of the BV Rules and 1.1.15, Part C of NK Rules.

4.5.3

End connections

4.5.3.aThis regulation has been specified referring to 3.5.3, Sec. 3, Chapter 4, Part B of the
BV Rules.

5. PRIMARY SUPPORTING MEMBERS
5.1

General

5.1.1
5.1.1.aThis is a general regulation related to structural continuity.

5.1.2
5.1.2.a

5.2

This regulation is specified for the case where the requirement of arrangement ofprimary supporting members specified in the rules differs from the actual
arrangement of primary supporting members.

Stiffening arrangement

5.2.1
5.2.1.aThe stiffeners to which this regulation is applicable are those installed to stiffen the
primary supporting members (girders). This regulation was established referring to
the rules of various classification Societies.

5.2.2
5.2.2.aThis regulation is based on 4.7.4, Section 3, Chapter 4, Part B of the BV Rules.

5.2.3
5.2.3.aThis regulation is based on 4.7.5, Section 3, Chapter 4, Part B of the BV Rules.

5.2.4
5.2.4.aThis regulation is based on 4.7.6, Section 3, Chapter 4, Part B of the BV Rules.

5.2.5
5.2.5.aThis regulation is based on 4.7.7, Section 3, Chapter 4, Part B of the BV Rules.

5.3

Span of primary supporting members

5.3.1

Definitions

5.3.1.aThis regulation is based on 1.1.16, Part C of NK Rules.

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5.4

Effective breadth of primary supporting member

5.4.1

General5.4.1.aIn principle, this is taken to the space of the primary supporting members, but when
the spaces of the adjacent supporting member vary, the average value is taken.

5.5

Geometric properties

5.5.1

General5.5.1.aSame as for stiffeners.

5.6

Bracketed end connection

5.6.1

General5.6.1.aThis regulation is based on 4.4, Section 3, Chapter 4, Part B of the BV Rules and1.1.14, Part C of NK Rules.

5.6.2

Dimensions of brackets

5.6.2.aThis regulation is based on 4.4, Section 3, Chapter 4, Part B of the BV Rules and1.1.14, Part C of NK Rules.

5.7

Cut-outs and holes

5.7.1
5.7.1.aThis regulation is based on C15.2.3 of NK Guidance and 4.6.1, Section 3, Chapter 4,
Part B of the BV Rules.

5.7.2
5.7.2.aThis regulation is based on C15.2.3 of NK Guidance and 4.6.2, Section 3, Chapter 4,
Part B of the BV Rules.

5.7.3
5.7.3.aThis regulation is based on C15.2.3 of NK Guidance and 4.6.3, Section 3, Chapter 4,
Part B of the BV Rules.

5.7.4
5.7.4.aThis regulation is based on C15.2.3 of NK Guidance and 4.6.4, Section 3, Chapter 4,
Part B of the BV Rules.

5.7.5
5.7.5.aThis regulation is based on C15.2.3 of NK Guidance and 4.6.5, Section 3, Chapter 4,
Part B of the BV Rules.

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6. DOUBLE BOTTOM
6.1

General

6.1.1

Double bottom extend

6.1.1.aThis is an installation requirement of double bottom based on the SOLAS
Convention.

6.1.2

Framing system

6.1.2.a

It is specified that the longitudinal framing system is mandatory for ships of length
120 m and greater.

6.1.3

Height of double bottom

6.1.3.a

The regulation is based on Chapter 31 of Part C of NK Rules.

6.1.4

Dimensions of double bottom

6.1.4.a

The regulation is base on C6.1.1-3 of NK Guidance.

6.1.5

Docking

6.1.5.aThis regulation is based on 6.2.4 of Part C of NK Rules (including requirements fordetailed arrangement). In CSR, however, since the requirements for arrangement
varies according to the arrangement of blocks in the dock, detailed numerical values
have not been specified.

6.1.6

Continuity of strength

6.1.6.aThis is a general regulation related to continuity of strength. The thickness of thelowermost strake in the hopper tank has been increased considering the continuity
with the inner bottom plating.

6.1.7

Reinforcement

6.1.7.aThis regulation is based on 6.2.1, Part C, of the NK Rules.

6.1.8

Manholes and lightening holes

6.1.8.aThis regulation is based on 6.1.2, Part C of the NK Rules.

6.1.9

Air holes and drain holes

6.1.9.aThis regulation is based on 6.1.2, Part C of the NK Rules.

6.1.10 Drainage of tank top
6.1.10.a This regulation is based on 6.1.3, Part C of NK Rules.

6.1.11 Striking plate
6.1.11.a This regulation is based on 6.1.4, Part C of NK Rules.

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6.1.12 Duct keel
6.1.12.a The arrangement of girder plating has been revised referring to the actual
arrangements in existing ships and the 31.2.2-5, Part C of NK Rules.

6.2

Keel

6.2.1
6.2.1.a

The width of one strake of the keel plate has been specified referring to theregulations of shear strake and bilge strake in 1.1.11, Part C of NK Rules.

6.3

Girders

6.3.1

Centre girder

6.3.1.aThis regulation is specified referring to the regulation of 31.2.2 and 6.2.1 of Part C of
NK Rules.

6.3.2

Side girder

6.3.2.aThis regulation is specified referring to the regulation of 31.2.2 and 6.2.1 of Part C of
NK Rules.

6.3.3

Spacing

6.3.3.aThis regulation is specified referring to the regulation of 31.2.2 and 6.2.1 of Part C of
NK Rules.

6.4

Floors

6.4.1

Spacing

6.4.1.aThis regulation is specified referring to the regulation of 31.3.2 and 6.3.1 of Part C of
NK Rules.

6.4.2

Floors in way of transverse bulkheads

6.4.2.aThis regulation is specified referring to the regulation of 31.3.2 and 6.3.1 of Part C of
NK Rules.

6.4.3

Web stiffeners

6.4.3.aThis regulation is specified referring to the regulation of 31.3.2 and 6.3.1 of Part C of
NK Rules.

6.5

Bilge strake and bilge keel

6.5.1

Bilge strake

6.5.1.a

6.5.2

Bilge keel

6.5.2.aSince a large number of comments from shipowners have been received about bilge
keel and prevention of damage to its ends, it was decided that the material of thebilge keel should have the same strength as the bilge strake. Similar to long hatch
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side coamings of 0.15L specified in the IACS UR S6, if the length of the bilge keel isgreater than 0.15L, the material of the bilge keel is required to be the same as that of
the bilge strake.

7. DOUBLE SIDE STRUCTURE
7.1

Application

7.1.1
7.1.1.a

7.2

The framing system of double skin side structure was considered to be either
longitudinal of transverse framing systems, and the application of each system has
been specified.

Design principles

7.2.1
7.2.1.aIf the double side skin part is to be used as a void space, and cargo of high density is
to be carried in the cargo holds, then local loads are not presumed to act on the sidestructure of the cargo hold on the double skin side. Even in such cases, appropriate
thickness exceeding the minimum thickness is considered necessary. As aconclusion, even if the double skin side part is a void space, it is treated as a ballast
tank and assessment of local strength is specified. Corrosion addition for the actual
service environment, that is, void space, is also specified.

7.3

Structural arrangement

7.3.1

General7.3.1.aIn principle, continuity of structure similar to that in double bottom structure has
been specified.

7.3.2

Primary supporting member spacing

7.3.2.aIn principle, continuity of structure similar to that in double bottom structure has
been specified.

7.3.3

Primary supporting member fitting

7.3.3.aIn principle, continuity of structure similar to that in double bottom structure has
been specified.

7.3.4

Transverse ordinary stiffeners

7.3.4.aIn principle, continuity of structure similar to that in double bottom structure has
been specified.

7.3.5

Longitudinal ordinary stiffeners

7.3.5.aIn principle, continuity of structure similar to that in double bottom structure has
been specified.

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7.3.6

Sheer strake

7.3.6.aIn principle, continuity of structure similar to that in double bottom structure has
been specified.

7.3.7

Plating connection

7.3.7.aIn principle, continuity of structure similar to that in double bottom structure has
been specified.

7.4

Longitudinally framed double side

7.4.1

General7.4.1.aIn principle, continuity of structure similar to that in double bottom structure has
been specified.

7.5

Transversely framed double side

7.5.1

General7.5.1.a

The principle for the continuity of structure in case of strut connection has
been specified.

8. SINGLE SIDE STRUCTURE
8.1

Application

8.1.1
8.1.1.a

8.2

Transverse framing system is used for the hold frames for stiffening the sidestructure. However, when web frames are installed or transverse girders are
installed, the requirement of arrangement for primary supporting members is used.

General arrangement

8.2.1
8.2.1.aThis regulation is specified referring to the regulation IACS UR S12 and considering
the net scantlings approach.

8.3

Side frames

8.3.1

General8.3.1.aThis regulation is specified referring to the regulation IACS UR S12 and considering
the net scantlings approach.

8.4

Upper and lower brackets

8.4.1
8.4.1.aThis regulation is specified referring to the regulation IACS UR S12 and considering
the net scantlings approach.

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8.4.2
8.4.2.a

8.5

This regulation is specified referring to the regulation IACS UR S12 and considering
the net scantlings approach.

Tripping brackets

8.5.1
8.5.1.a

8.6This regulation is specified referring to the regulation IACS UR S12 and considering
the net scantlings approach.

Support structure

8.6.1
8.6.1.aThis regulation is specified referring to the regulation IACS UR S12 and considering
the net scantlings approach.

9. DECK STRUCTURE
9.1

Application

9.1.1
9.1.1.a

9.2

In principle, the topside tank structure is required to use the longitudinal framing
system regardless of the length of the ship.

General arrangement

9.2.1
9.2.1.a

The arrangement of girders of the topside tanks is specified here considering
longitudinal strength, lateral loads, hatches, bulkhead positions and so on, and thespacing of the girders is specified referring to the existing arrangements.

9.2.2
9.2.2.a

It is considered that for this topic, no information in addition to that shown in theRules is necessary to explain the background.

9.2.3

Deck between hatches

9.2.3.aThe deck structure between hatches, the so-called cross-deck structure, is required
to use the transverse framing system, in principle, since in-plane compressive loads
in the breadth direction of the ship transmitted from the side shell plating are
dominant. Beams to which the rule "beams shall be supported by appropriate
girders, and shall extend to the second longitudinal stiffener toward the bulwark
from the hatch side girder" applies, are generally girders of the transverse framing
system that do not fall under the scope of general stiffeners.

9.2.4

Topside tank structures

9.2.4.a

The continuity of structure with transverse members has been specified. The
transverse girder arrangement of topside tanks depends on the bulkheadarrangement and the arrangement of hatch coamings. For the girder arrangement in
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a double side skin structure, the continuity with the double bottom structure isconsidered, and since all the transverse members are not installed in practice in thesame plane, the installation of large brackets supporting the girders of the double
skin side structure in the topside tanks has been approved.

9.2.5

Stringer plate

9.2.5.a

The regulation for usage categories of steel in Section 1, Chapter 3 incorporating
IACS UR S6 is for stringer plates in the region of 0.4L amidships. This regulation
applies to the entire cargo region.

9.2.6
9.2.6.a

The continuity of structure with bracket connection has been specified.

9.2.7
9.2.7.a

General regulations for supporting structures fitted on the heavy equipment are
specified.

9.2.8
9.2.8.a

General regulations for supporting structures fitted on the heavy equipment are
specified.

9.2.9
9.2.9.a

General regulation for the discontinuity part such as ends and corners of
deckhouses or superstructures are specified.

9.2.10 Connection of hatch end beams with deck structures
9.2.10.a9.2.11 Construction of deck plating
9.2.11.a General regulation in order to stress concentration around the openings are
specified.

9.3

Longitudinally framed deck

9.3.1

General9.3.1.aRegulations related to continuity of strength in longitudinal framing systems are
specified.

9.4

Transversely framed deck

9.4.1

General9.4.1.aRegulations related to continuity of strength in transverse framing systems are
specified.

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9.5

Hatch supporting structures

9.5.1
9.5.1.aRegulations related to continuity of strength of hatch supporting structures are
specified.

9.5.2
9.5.2.aRegulations related to continuity of strength of hatch supporting structures are
specified.

9.5.3
9.5.3.aRegulations related to continuity of strength of hatch supporting structures are
specified.

9.5.4
9.5.4.aRegulations related to continuity of strength of hatch supporting structures are
specified.

9.6

Openings in the strength deck

9.6.1

General9.6.1.aThis regulation is based on 6.1.1, Section 6, Chapter 4, Part B of the BV Rules.

9.6.2

Small opening location

9.6.2.aThis regulation is based on 6.1., Section 6, Chapter 4, Part B of the BV Rules.

9.6.3

Corner of hatchways

9.6.3.aThis regulation is based on 6.2., Section 6, Chapter 4, Part B of the BV Rules.

10. BULKHEAD STRUCTURE
10.1 Application
10.1.110.1.1.a This regulation is applicable to longitudinal bulkheads also considering double skinside structure.

10.1.2 Plane bulkheads
10.1.2.a The type of bulkhead structure is described, based on 1.1.2, Section 7, Chapter 4,
Part B of the BV Rules.

10.2 General
10.2.110.2.1.a This regulation is based on 1.2.7, Section 7, Chapter 4, Part B of the BV Rules.
However, although this regulation applies to longitudinal bulkheads in the original
document, generally the lateral loads considered in the lower part of the bulkhead
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are greater than the loads on the upper part of the bulkhead, therefore, thisregulation applies to all the bulkheads.

10.2.210.2.2.a This regulation is based on 2.1.6, Section 7, Chapter 4, Part B of the BV Rules.

10.3 Plane bulkheads
10.3.1 General
10.3.1.a In principle, this regulation is based on the regulations 2.1.1 to 2.1.5, Section 7,
Chapter 4, Part B of the BV Rules.

10.3.2 End connection of ordinary stiffeners
10.3.2.a This regulation is based on the regulations 2.2.1 and 2.2.2, Section 7, Chapter 4, Part
B of the BV Rules.

10.3.3 Sniped end of ordinary stiffener
10.3.3.a This regulation is based on the regulation 2.2.4, Section 7, Chapter 4, Part B of the
BV Rules.

10.3.4 Bracketed ordinary stiffeners
10.3.4.a In principle, this regulation is based on the regulations 2.3.1 and 2.3.2, Section 7,
Chapter 4, Part B of the BV Rules.

10.4 Corrugated bulkheads
10.4.1 General
10.4.1.a CSR requires that strength assessment of primary supporting members be
performed based on the direct strength calculation, and also requires hull girder
ultimate strength and fatigue strength assessment to be performed for ships oflength 150 m and greater. This regulation also covers strength requirements during
flooding of IACS UR S17, S18, S20, and also IACS URS25 specified for ships of 150
m and greater. These applications are considered for consistent treatment. The
treatment of stools in corrugated bulkheads considering construction that is morerobust than used currently, has been made more stringent by application of theregulations for ships of length 190 m and greater in UR S18 to ships of length 150 m
and greater.

10.4.2 Construction
10.4.2.a In principle, this regulation is based on IACS UR S18.

10.4.3 Actual section modulus of corrugations
10.4.3.a In principle, this regulation is based on IACS UR S18.

10.4.4 Span of corrugations
10.4.4.a In principle, this regulation is based on IACS UR S18.

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10.4.5 Structural arrangement
10.4.5.a In principle, this regulation is based on IACS UR S18.

10.4.6 Bulkhead stools
10.4.6.a In principle, this regulation is based on IACS UR S18.

10.4.7 Lower stool
10.4.7.a In principle, this regulation is based on IACS UR S18.

10.4.8 Upper stool
10.4.8.a In principle, this regulation is based on IACS UR S18.

10.4.9 Alignment
10.4.9.a In principle, this regulation is based on IACS UR S18.

10.4.10 Effective width of the compression flange
10.4.10.a In principle, this regulation is based on IACS UR S18.

10.4.11 Effective shedder plates
10.4.11.a In principle, this regulation is based on IACS UR S18.

10.4.12 Effective gusset plates
10.4.12.a In principle, this regulation is based on IACS UR S18.

10.4.13 Section modulus at the lower end of corrugations
10.4.13.a In principle, this regulation is based on IACS UR S18.

10.4.14 Section modulus at sections other than the lower end of corrugations
10.4.14.a In principle, this regulation is based on IACS UR S18.

10.4.15 Shear area
10.4.15.a In principle, this regulation is based on IACS UR S18.

10.5 Non-tight bulkheads
10.5.1 Non-tight bulkheads not acting as pillars
10.5.1.a This regulation is based on 4.1.1, Section 7, Chapter 4, Part B of the BV Rules.

10.5.2 Non-tight bulkheads acting as pillars
10.5.2.a This regulation is based on 4.2, Section 7, Chapter 4, Part B of the BV Rules.

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10.6 Watertight bulkheads of trunks and tunnels
10.6.1
10.6.1.a This regulation is in accordance with a part of the rule 19 of Chapter II-1 of the
SOLAS.

11. PILLARS
11.1 General
11.1.111.1.1.a This regulation is based on 4.1.1, Section 6, Chapter 4, Part B of the BV Rules.

11.1.2
11.1.2.a This regulation is based on 4.1, Section 6, Chapter 4, Part B of the BV Rules.

11.1.311.1.3.a This regulation is based on 4.1.3, Section 6, Chapter 4, Part B of the BV Rules.

11.1.4 Connections
11.1.4.a This regulation is based on 4.2, Section 6, Chapter 4, Part B of the BV Rules.

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