COMMON STRUCTURAL RULES FOR BULK CARRIERSJ U L Y 2012

Corrigenda 1
Rule Editorials
Notes: (1)(2)

These Rule Corrigenda enter into force on 1st July 2012.
These Rule Corrigenda should be read in conjunction with the July 2012 consolidated
edition of Bulk Carriers CSR.
Copyright in these Common Structural Rules for Bulk Carriers is owned by:American Bureau of Shipping
Bureau Veritas
China Classification Society
Det Norske Veritas
Germanischer Lloyd
Korean Register of Shipping
Lloyd's Register
Nippon Kaiji Kyokai
Registro Italiano Navale
Russian Maritime Register of Shipping
Copyright © 2012
The IACS members, their affiliates and subsidiaries and their respective officers, employees or agentsare, individually and collectively, referred to in this clause as the ‘IACS Members’. The IACS
Members, individually and collectively, assume no responsibility and shall not be liable to any person
for any loss, damage or expense caused by reliance on the information or advice in this document or
howsoever provided, unless that person has signed a contract with the relevant IACS Member entity
for the provision of this information or advice and in that case any responsibility or liability is
exclusively on the terms and conditions set out in that contract.

Common Structural Rules for Bulk Carriers

July 2012 Edition

For technical background for Rule Corrigenda in this present document, reference is made to separate document
Technical Background for Rule Corrigenda.

Corrigenda 1 to July 2012 Editioni / iv

Common Structural Rules for Bulk Carriers

July 2012 Edition

List of changes
CHAPTER 2

GENERAL ARRANGEMENT DESIGN ............................................................ 1

Section 1

Subdivision Arrangement ................................................................................... 1
3. After peak, machinery space bulkheads and stern tubes ..................................................... 1
3.1.5 Stern Tubes..........................................................................................................................1

CHAPTER 6

HULL SCANTLINGS ...................................................................................... 2

Section 3

Buckling and ultimate strength of ordinary stiffeners and stiffened panels .. 2
Symbols......................................................................................................................................... 2

CHAPTER 11

CONSTRUCTION AND TESTING ................................................................... 3

Section 3

Testing of Compartments.................................................................................... 32
2.3

Testing Method ................................................................................................................. 3
Hose Testing........................................................................................................................3
2.3.1...............................................................................................................................3

CHAPTER 13

SHIPS IN OPERATION, RENEWAL CRITERIA .............................................. 4

Section 1

Maintenance of Class........................................................................................... 4
1
1.1

1.2

General .............................................................................................................................. 4
Application ..........................................................................................................................4
1.1.2
Void .......................................................................................................................4
1.1.3
Void .......................................................................................................................4
Definitions ...........................................................................................................................4
1.2.3
Deck zone ..............................................................................................................4
1.2.4
Bottom zone ...........................................................................................................5
1.2.5
Neutral axis zone ...................................................................................................5

Thickness Measurement and acceptance criteria ............................................. 5

Section 2

Symbols ..........................................................................................................................................5
1
Application ........................................................................................................................ 6
1.1.1 General ................................................................................................................................6
1.1.1...............................................................................................................................6
2
2.1
2.2

2.3

ii / iv

Rule requirements for the extent of measurements and the determination oflocations............................................................................................................................. 6
General ................................................................................................................................6
2.1.1...............................................................................................................................6
Class renewal survey ...........................................................................................................7
2.2.1...............................................................................................................................7
2.2.2...............................................................................................................................8
Number and locations of measurements..............................................................................8
2.3.1
Number of measurements ......................................................................................8Corrigenda 1 to July 2012 Edition

Common Structural Rules for Bulk Carriers

2.3.2
3.
3.1

3.2

3.3

Section 2

July 2012 Edition

Locations of measurements ...................................................................................8

Acceptance Criteria........................................................................................................ 13
Definitions .........................................................................................................................13
3.1.1
Deck zone ............................................................................................................13
3.1.2
Bottom zone .........................................................................................................14
3.1.3
Neutral axis zone .................................................................................................14
Local strength criteria........................................................................................................143.2.1
Items for the local strength criteria.....................................................................14
3.2.2
Renewal thickness for corrosion other than local corrosion...............................15
3.2.3
Renewal thickness for local corrosion.................................................................15
Global strength criteria ......................................................................................................163.3.1
Items for the global strength criteria...................................................................16
3.3.2
Renewal thickness................................................................................................16

Acceptance criteria ............................................................................................ 17
Symbols....................................................................................................................................... 17
1.
1.1
1.2
1.3
1.4

Local strength criteria.................................................................................................... 18
Application ........................................................................................................................18
1.1.1.............................................................................................................................18
Renewal thickness for corrosion other than local corrosion..............................................18
1.2.1.............................................................................................................................18
Renewal thickness for local corrosion...............................................................................18
1.3.1.............................................................................................................................18
Global strength criteria ......................................................................................................19
1.4.1
Items for the global strength criteria...................................................................19
1.4.2
Renewal thickness................................................................................................19

Corrigenda 1 to July 2012 Edition

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Common Structural Rules for Bulk Carriers

July 2012 Edition

Chapter 2 GENERAL ARRANGEMENT DESIGN

Section 1

Subdivision Arrangement

3. After peak, machinery space bulkheads and stern tubes
PH11005_IHw

The following text unintentionally removed from the last revision is reinstated withcorrected references:

3.1.5 Sterntubes
Ref. SOLAS Ch. II-1, Part B-2, Reg.12
Sterntubes are to be enclosed in a watertight space (or spaces) of moderate volume. Other measures
to minimise the danger of water penetrating into the ship in case of damage to sterntube
arrangements may be taken at the discretion of the Society.

Corrigenda 1 to July 2012 Edition1Common Structural Rules for Bulk Carriers

July 2012 Edition

Chapter 6 Hull Scantlings

Section 3

Buckling and ultimate strength of ordinary stiffeners andstiffened panels

Symbols
PH5035e

The following table is modified as follow:
Table 1:

Stiffeners sniped at both ends
Guidance values where bothends are effectively connectedto adjacent structures (1)Correction factor F1
F1 (2)
1.00
1.05

Flat bar

1.10

Bulb section

1.201.21

Edge stiffener

Angle and tee-sections

1.30

Girders of high rigidity(e.g. bottom transverses)(1)
Exact values may be determined by direct calculations.
(2)
An average value of F1 is to be used for plate panels having different edge
stiffeners.

2

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Common Structural Rules for Bulk Carriers

July 2012 Edition

Chapter 11 Construction and Testing

Section 3

2

Testing Method

2.3

Hose Testing

KC 1022

Testing of Compartments

The following text is modified as follow:

2.3.1
When hose testing is required to verify the tightness of the structures, as defined in Tab 1, theminimum pressure in the hose, at least equal to 2·105 0.20·105 Pa, is to be applied at a maximum
distance of 1.5 m. The nozzle diameter is not to be less than 12 mm.

Corrigenda 1 to July 2012 Edition3

Common Structural Rules for Bulk Carriers

July 2012 Edition

Chapter 13

Ships in Operation, Renewal Criteria

Section 1

1

General1.1

Application

PH11007

1.1.2

Maintenance of Class

The following requirement is deleted and replaced by term “void”:
VoidThis Chapter is intended to provide Owners, companies performing thickness measurements andSociety’s Surveyors with a uniform procedure in order to fulfil rule requirements for thickness
measurements. In particular, it will enable all the above-mentioned parties to carry out:•

the planning and preparation•

the determination of extent and location•

the analysisof the thickness measurements.

PH11007

1.1.3

The following requirement is deleted and replaced by term “void”:
VoidThis Chapter also takes into account specific requirements for thickness measurements relevant toclose-up surveys within the scope of the Enhanced Survey Program (ESP) of single side skin bulk
carriers and double side skin bulk carriers.

1.2
PH11007

1.2.3

Definitions

The following requirement is added:
Deck zone
The deck zone includes all the following items contributing to the hull girder strength above thehorizontal strake of the topside tank or above the level corresponding to 0.9D above the base line if
there is no topside tank:•4

strength deck plating

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Common Structural Rules for Bulk Carriers

PH11007

1.2.4

July 2012 Edition•

deck stringer•

sheer strake•side shell plating•

top side tank sloped plating, including horizontal and vertical strakes•

longitudinal stiffeners connected to the above mentioned platings.

The following requirement is added:
Bottom zone
The bottom zone includes the following items contributing to the hull girder strength up to the upper
level of the hopper sloping plating or up to the inner bottom plating if there is no hopper tank:

PH11007

1.2.5•

keel plate•bottom plating•bilge plate•bottom girders•

inner bottom plating•

hopper tank sloping plating•side shell plating•

longitudinal stiffeners connected to the above mentioned platings.

The following requirement is added:
Neutral axis zone
The neutral axis zone includes the plating only of the items between the deck zone and the bottom
zone, as for example:

PH11007•side shell plating•

inner hull plating, if any.

The following section and its content is deleted:

Section 2

Thickness Measurement and acceptance criteria

Symbols
For symbols not defined in this Section, refer to Ch 1, Sec 4.

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5Common Structural Rules for Bulk Carriers

trenewal:

July 2012 Edition

Renewal thickness; Minimum allowable thickness, in mm, below which renewalof structural members is to be carried out
trenewal = tas_built – tC – tvoluntary_addition:

treserve

Reserve thickness; Thickness, in mm, to account for anticipated thickness
diminution that may occur during a survey interval of 2.5 year. (treserve = 0.5 mm)

tC:

Corrosion addition, in mm, defined in Ch 3, Sec3

tas_built:

As built thickness, in mm, including tvoluntary_addition , if any

tvoluntary_addition:

Voluntary thickness addition; Thickness, in mm, voluntarily added as the
Owner’s extra margin for corrosion wastage in addition to tC:

tgaugedGauged thickness, in mm, on one item, i.e average thickness on one item using
the various measurements taken on this same item during periodical ship’s inservice surveys.

1

Application

1.1.1

General1.1.1This section provides the following information:• references to rule requirements and some additional information on the extent of the thickness
measurements to be performed during surveys (see [2.1] and [2.2])• locations of the measurements for the main parts of the ship (see [2.3])• how to apply the acceptance criteria (see [3]).
Tables are also given to detail the above items. The sketches are given as an example to illustrate therequirements.

2

Rule requirements for the extent of measurements and the determination oflocations2.1

General

2.1.1
For the maintenance of class, thickness measurements are required during intermediate and classrenewal surveys and may be required during annual surveys.

6

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July 2012 Edition

Tab 1 gives the references to the minimum requirements for thickness measurements related to thedifferent types of surveys.
Table 1:

References to rule requirements related to thickness
measurements

Class renewal survey
Outside the cargo length area:
UR Z7:• systematic measurements andsuspect areas.
• where substantial corrosion isfound, the extent of thickness
measurements may be increased
to the Surveyor’s satisfaction.
Within the cargo length area:a) single side skin bulk carriers:
UR Z10.2:• planning and general
requirements• measurements of elements
subjected to close-up survey• extent of systematic thickness
measurements• according to the different
locations, where substantial
corrosion is foundb) double side skin bulk carriers:
UR Z10.5:• planning and general
requirements• measurements of elements
subjected to close-up survey• extent of systematic thickness
measurements• according to the different
locations, where substantial
corrosion is found

2.2

Intermediate survey
Annual survey
Outside the cargo length area:
Outside the cargo length area:
UR Z7:UR Z7:• thickness measurements to be taken • areas of substantial corrosion
if deemed necessary by theidentified at previous class renewal
Surveyor.
or intermediate surveys;• where substantial corrosion is• where substantial corrosion isfound, the extent of thickness
found, the extent of thickness
measurements may be increased to measurements may be increased to
the Surveyor’s satisfaction.
the Surveyor’s satisfaction.
Within the cargo length area:
Within the cargo length area:a) single side skin bulk carriers:a) single side skin bulk carriers:
UR Z10.2:
UR Z10.2:
Ships 10 years of age or less:• for cargo holds and when deemednecessary by the Surveyor• for cargo holds• for salt ballast tanks and when
• for salt ballast tanks• according to the different locations, deemed necessary by the Surveyor
where substantial corrosion is found • according to the different locations,where substantial corrosion is foundShips over 10 years of age:• see references given for classrenewal survey• according to the different locations,where substantial corrosion is foundb) double side skin bulk carriers:b) double side skin bulk carriers:
UR Z10.5:
UR Z10.5:
Ships 10 years of age or less:• for cargo holds and when deemednecessary by the Surveyor• for cargo holds• for salt ballast tanks and when
• for salt ballast tanks• according to the different locations, deemed necessary by the Surveyor
where substantial corrosion is found • according to the different locations,where substantial corrosion is foundShips over 10 years of age:• see references given for classrenewal survey• according to the different locations,where substantial corrosion is foundClass renewal survey

2.2.1
The thickness measurements required by the Rules consist of:• systematic thickness measurements in order to assess the global and local strength of the ship
• thickness measurements as indicated in the program of close-up survey• measurements of elements considered as suspect areas

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Common Structural Rules for Bulk Carriers

July 2012 Edition• additional measurements on areas determined as affected by substantial corrosion.

2.2.2
For the determination of close-up surveys and relevant thickness measurements as well as the areas
considered as suspect areas, reference is to be made to the relevant Sections of the following IACS
Unified Requirements:• for the hull structure and piping systems in way of cargo holds, cofferdams, pipe tunnels, void
spaces, fuel oil tanks within the cargo length area and all ballast tanks:• UR Z10.2 “Hull surveys of single skin bulk carriers”• UR Z10.5 “Hull surveys of double skin bulk carriers”• for the remainder of the ship outside the cargo length area:• UR Z7.

2.3

Number and locations of measurements

2.3.1

Number of measurements
Considering the extent of thickness measurements as required by the Rules and indicated in [2.1] and[2.2], the locations of the points to be measured are given for the most important items of thestructure.

2.3.2

Locations of measurements
Tab 2 provides explanations and/or interpretations for the application of those requirements indicatedin the Rules which refer to both systematic thickness measurements related to the calculation of global
hull girder strength and specific measurements connected to close-up surveys.
Fig 1 to Fig 5 are provided to facilitate the explanations and/or interpretations given in Tab 2, to show
typical arrangements of single side skin bulk carriers and double side skin bulk carriers.
Table 2:

Interpretations of rule requirements for the locations
and number of points to be measured

Interpretation
Figure reference
Item
Selected plates on deck, tank top,
«Selected» means at least a single point onbottom, double bottom and wind-and- one out of three plates, to be chosen on
water area
representative areas of average corrosion
All deck, tank top and bottom plates and At least two points on each plate to bewind-and-water strakes
taken either at each 1/4 extremity of plateor at representative areas of average
corrosion
Transverse section
Single side skin bulk carrier:Fig 1 for single and doubleside skin bulk carriers
A transverse section includes all
longitudinal members such as plating,longitudinals and girders at the deck, side,
bottom; inner bottom and hopper side
plating, longitudinal bulkhead and bottom

8

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Common Structural Rules for Bulk Carriers

Item

July 2012 Edition

Interpretation
plating in top wing tanks.

Figure reference

Double side skin bulk carrier:
A transverse section includes all
longitudinal members such as plating,longitudinals and girders at the deck, sides,
bottom, inner bottom, hopper sides, innersides and top wing inner sides.
Cargo hold hatch covers and coamings

Fig 2

Selected internal structure such as floors The internal structural items to be measured
and longitudinals, transverse frames,in each space internally surveyed are to be
web frames, deck beams, girders
at least 10% outside the cargo length area
Two single points on each deck plate (to betaken either at each 1/4 extremity of plateor at representative areas of average
corrosion) between the ship sides and hatchcoamings in the transverse section
concerned
Selected areas of all deck plating inside «Selected» means at least a single point on Extent of areas is shown inline of hatch openings
one out of three plates, to be chosen on
UR Z10.2 for single side
representative areas of average corrosion skin bulk carriers and UR
Z10.5 for double side skin
«All deck plating» means at least two
bulk carriers
points on each plate to be taken either at
each 1/4 extremity of plate or atrepresentative areas of average corrosion
Selected side shell frames in cargo holds 25% of frames: one out of four frames
Extent of areas is shown infor single side skin bulk carriers
should preferably be chosen throughout the UR Z10.2 for single sidecargo hold length on each sideskin bulk carriers.
«Selected frames» means at least 3 frames Locations of points are givenon each side of cargo holds
in Fig 3 for single side skinbulk carriers
Transverse frame in double skin tank
Fig 1
Transverse section of deck plating
outside line of cargo hatch openings

Includes bulkhead plating, stiffeners and Areas of measurements aregirders, including internal structure ofshown in UR Z10.2 forupper and lower stools, where fitted.
single side skin bulk carriersand UR Z10.5 for double
Two selected bulkheads: one is to be thebulkhead between the two foremost cargo side skin bulk carriers.
Locations of points are given
holds and the second may be chosen inother positionsin Fig 4.
Areas of measurements are
One transverse bulkhead in each cargo This means that the close-up survey andholdrelated thickness measurements are to be shown in UR Z10.2 forperformed on one side of the bulkhead; the single side skin bulk carriers
side is to be chosen based on the outcome and UR Z10.5 for doubleof the overall survey of both sides. In the side skin bulk carriers.
event of doubt, the Surveyor may also
Locations of points are given
require (possibly partial) close-up survey in Fig 4.
on the other side
The ballast tank is to be chosen based on Locations of points are given
Transverse bulkheads in one
topside/side ballast tankthe history of ballasting among those prone in Fig 5
to have the most severe conditions
Transverse bulkheads in cargo holds

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9

Common Structural Rules for Bulk Carriers

Item
Transverse webs in ballast tanks

July 2012 Edition

Interpretation
Figure reference
One of the representative tanks of each type Extent of areas is shown in(i.e. topside or hopper or side tank) is to be UR Z10.2 for single sidechosen in the forward partskin bulk carriers and in UR
Z10.5 for double side skinbulk carriers.
Locations of points are given
in Fig 3.

Single side bulk carriers

Double side bulk carrier
Note: Measurements are to be taken on both port and starboard sides of the selected transverse section.
Figure 1:

10Transverse section of bulk carrier

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Common Structural Rules for Bulk Carriers

July 2012 Edition

1
L/4

1
L/2

1
3L/4

2

2

2

2

3
1
$

$

$

2

$

3

50 mm

Notes :
1. Three sections at L/4, L/2, 3L/4 of hatch cover length, including:• one measurement of each hatch cover plate and skirt plate• measurements of adjacent beams and stiffeners• one measurement of coaming plates and coaming flange, each side
2. Measurements of both ends of hatch cover skirt plate, coaming plate and coaming flange
3. One measurement of one out of three hatch coaming brackets and bars, on both sides and both ends
Figure 2:

Locations of measurements on hatch covers and coamings

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Common Structural Rules for Bulk Carriers

July 2012 Edition

Note : The gauging pattern for web plating is to be a three point pattern for zones A, C and D, and a two point
pattern for zone B (see figure). The gauging report is to reflect the average reading. The average reading is to becompared with the allowable thickness. If the web plating has general corrosion then this pattern is to be
expanded to a five point pattern.
Figure 3:

Locations of measurements on structural members in cargo holds and ballast
tanks of single side skin bulk carriers

A

B

B

Case with stools

Case without stools

A-A

A

B-B

Note: Measurements to be taken in each shaded area as per views A - A and B – B

12Corrigenda 1 to July 2012 Edition

Common Structural Rules for Bulk Carriers

Figure 4:

July 2012 Edition

Locations of measurements on cargo hold transverse bulkheads

Note: Measurements to be taken in each vertical section as per view A - A
Figure 5:

Locations of measurements on transverse bulkheads of topside, hopper, double
hull and double bottom tanks

3.

Acceptance Criteria

3.1

Definitions

3.1.1

Deck zone
The deck zone includes all the following items contributing to the hull girder strength above thehorizontal strake of the topside tank or above the level corresponding to 0.9D above the base line if
there is no topside tank:• strength deck plating• deck stringer• sheer strake

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Common Structural Rules for Bulk Carriers

July 2012 Edition• side shell plating• top side tank sloped plating, including horizontal and vertical strakes• longitudinal stiffeners connected to the above mentioned platings.

3.1.2

Bottom zone
The bottom zone includes the following items contributing to the hull girder strength up to the upper
level of the hopper sloping plating or up to the inner bottom plating if there is no hopper tank:• keel plate• bottom plating• bilge plate• bottom girders• inner bottom plating• hopper tank sloping plating• side shell plating• longitudinal stiffeners connected to the above mentioned platings.

3.1.3

Neutral axis zone
The neutral axis zone includes the plating only of the items between the deck zone and the bottom
zone, as for example:• side shell plating• inner hull plating, if any

3.2

Local strength criteria

3.2.1

Items for the local strength criteria
The items to be considered for the local strength criteria are those of the deck zone, the bottom zone
and the neutral axis zone, as defined in [0], and the additional following items:• hatch coaming plating• hatch coaming brackets• hatch cover top plating• hatch cover skirt plating• hatch cover stiffeners• transverse bulkheads plating• transverse bulkheads stiffener web• transverse bulkheads stiffener flange• side shell frames web• side shell frames flange• side shell frames brackets

14

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Common Structural Rules for Bulk Carriers

July 2012 Edition• web of topside and hopper tank web frames• flange of topside and hopper tank web frames• floors plating and stiffeners• forward and aft peak bulkheads plating• forward and aft peak bulkheads stiffener web• forward and aft peak bulkheads stiffener flange• stringers and girders.

3.2.2

Renewal thickness for corrosion other than local corrosion
For each item, steel renewal is required when the gauged thickness tgauged is less than the renewal
thickness, as specified in the following formula:tgauged < trenewal,
Where the gauged thickness tgauged is such as:trenewal < tgauged < trenewal + treservecoating applied in accordance with the coating manufacturer’s requirements or annual gauging may be
adopted as an alternative to the steel renewal. The coating is to be maintained in good condition.

3.2.3

Renewal thickness for local corrosion
If pitting intensity in an area where coating is required, according to Ch 3, Sec 5, is higher than 15%(see Fig 6), thickness measurements are to be performed to check the extent of pitting corrosion. The
15% is based on pitting or grooving on only one side of a plate.
In cases where pitting is exceeding 15%, as defined above, an area of 300 mm or more, at the mostpitted part of the plate, is to be cleaned to bare metal and the thickness is to be measured in way of thefive deepest pits within the cleaned area. The least thickness measured in way of any of these pits is tobe taken as the thickness to be recorded.
The minimum remaining thickness in pits, grooves or other local areas as defined in Ch 13, Sec1,[1.2.1] is to be greater than:• 75% of the as-built thickness, in the frame and end brackets webs and flanges• 70% of the as-built thickness, in the side shell, hopper tank and topside tank plating attached to theeach side frame, over a width up to 30 mm from each side of it,
without being greater than trenewal.

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Common Structural Rules for Bulk Carriers

Figure 6:

July 2012 Edition

Pitting intensity diagrams (from 5% to 25% intensity)

3.3

Global strength criteria

3.3.1

Items for the global strength criteria
The items to be considered for the global strength criteria are those of the deck zone, the bottom zone
and the neutral axis zone, as defined in [0].

3.3.2

Renewal thickness
The global strength criteria is defined by the assessment of the bottom zone, deck zone and neutral
axis zone, as detailed below.
a)bottom zone and deck zone:

The current hull girder section modulus determined with the thickness measurements is not to be lessthan 90% of the section modulus calculated according to Ch 5, Sec 1 with the gross offered
thicknesses.
Alternatively, the current sectional areas of the bottom zone and of the deck zone which are the sumof the gauged items area of the considered zones, are not to be less than 90% of the sectional area ofthe corresponding zones determined with the gross offered thicknesses.
b) neutral axis zone:

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July 2012 Edition

The current sectional area of the neutral axis zone, which is the sum of the gauged platings area of thiszone, is not to be less than 85% of the gross offered sectional area of the neutral axis zone.
If the actual wastage of all items, of a given transverse section, which contribute to the hull girderstrength is less than 10% for the deck and bottom zones and 15% for the neutral axis zone, the global
strength criteria of this transverse section is automatically satisfied and its checking is no more
required.

PH11007

The following section and its content are added (in addition, references are
updated):Section 2

Acceptance criteria

Symbols
For symbols not defined in this Section, refer to Ch 1, Sec 4.
trenewal:

Renewal thickness; Minimum allowable thickness, in mm, below which renewalof structural members is to be carried out
trenewal = tas_built – tC – tvoluntary_addition

treserve:

Reserve thickness; Thickness, in mm, to account for anticipated thickness
diminution that may occur during a survey interval of 2.5 year. (treserve = 0.5 mm)

tC:

Corrosion addition, in mm, defined in Ch 3, Sec3

tas_built:

As built thickness, in mm, including tvoluntary_addition , if any

tvoluntary_addition:

Voluntary thickness addition; Thickness, in mm, voluntarily added as the
Owner’s extra margin for corrosion wastage in addition to tC

tgauged:Gauged thickness, in mm, on one item, i.e average thickness on one item using
the various measurements taken on this same item during periodical ship’s inservice surveys.

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Common Structural Rules for Bulk Carriers

1.

Local strength criteria

1.1

Application

July 2012 Edition

1.1.1
The items to be considered for the local strength criteria are those defined in UR Z10.2 for single sideskin bulk carriers and UR Z10.5 for double side skin bulk carriers.

1.2

Renewal thickness for corrosion other than local corrosion

1.2.1
For each item, steel renewal is required when the gauged thickness tgauged is less than the renewal
thickness, as specified in the following formula:tgauged < trenewal,
Where the gauged thickness tgauged is such as:trenewal < tgauged < (trenewal + treserve)
coating applied in accordance with the coating manufacturer’s requirements or annual gauging may be
adopted as an alternative to the steel renewal. The coating is to be maintained in good condition.

1.3

Renewal thickness for local corrosion

1.3.1
If pitting intensity in an area where coating is required, according to Ch 3, Sec 5, is higher than 15%(see Fig 1), thickness measurements are to be performed to check the extent of pitting corrosion. The
15% is based on pitting or grooving on only one side of a plate.
In cases where pitting is exceeding 15%, as defined above, an area of 300 mm or more, at the mostpitted part of the plate, is to be cleaned to bare metal and the thickness is to be measured in way of thefive deepest pits within the cleaned area. The least thickness measured in way of any of these pits is tobe taken as the thickness to be recorded.
The minimum remaining thickness in pits, grooves or other local areas as defined in Ch 13, Sec 1,[1.2.1] is to be greater than:• 75% of the as-built thickness, in the frame and end brackets webs and flanges• 70% of the as-built thickness, in the side shell, hopper tank and topside tank plating attached to theeach side frame, over a width up to 30 mm from each side of it,
without being greater than trenewal.

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Figure 1:

July 2012 Edition

Pitting intensity diagrams (from 5% to 25% intensity)

1.4

Global strength criteria

1.4.1

Items for the global strength criteria
The items to be considered for the global strength criteria are those of the deck zone, the bottom zone
and the neutral axis zone, as defined in Ch 13, Sec 1, [1.2].

1.4.2

Renewal thickness
The global strength criteria is defined by the assessment of the bottom zone, deck zone and neutral
axis zone, as detailed below.
a)bottom zone and deck zone:

The current hull girder section modulus determined with the thickness measurements is not to be lessthan 90% of the section modulus calculated according to Ch 5, Sec 1 with the gross offered
thicknesses.
Alternatively, the current sectional areas of the bottom zone and of the deck zone which are the sumof the gauged items area of the considered zones, are not to be less than 90% of the sectional area ofthe corresponding zones determined with the gross offered thicknesses.
b) neutral axis zone:
The current sectional area of the neutral axis zone, which is the sum of the gauged platings area of thiszone, is not to be less than 85% of the gross offered sectional area of the neutral axis zone.

Corrigenda 1 to July 2012 Edition

19

Common Structural Rules for Bulk Carriers

July 2012 Edition

If the actual wastage of all items, of a given transverse section, which contribute to the hull girderstrength is less than 10% for the deck and bottom zones and 15% for the neutral axis zone, the global
strength criteria of this transverse section is automatically satisfied and its checking is no more
required.

20

Corrigenda 1 to July 2012 Edition