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IACS Common Structural Rules. Bulk Carriers. MTPNO876 – Bulk Carriers and Container Ships 01 March 2006. IACS CSR. Individual society Rules. Safety level. What is CSR?. Rules covering structural requirement for Bulk Carriers and Tankers, both newbuilding and in service

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iacs common structural rules

IACS Common Structural Rules

Bulk Carriers

MTPNO876 – Bulk Carriers and Container Ships

01 March 2006

what is csr

IACS CSR

Individual society Rules

Safety level

What is CSR?
  • Rules covering structural requirement for Bulk Carriers and Tankers, both newbuilding and in service
  • A Rule set applied in a systematic manner utilising state of the art computational methods for more extensive direct calculations
  • Vessels built to CSR shall have overall safety of the hull structure equivalent to or better than that currently achieved in relation to life, environment and property
  • Safety level exceeding any IACS members existing Rules.

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why csr
Why CSR?
  • To eliminate competition between class societies with respect to structural requirements and standards
  • To employ the combined experience and recourses of all IACS societies to develop a single standard, or set of Rules
  • To ensure that a vessel meeting this new standard will be recognised by the industry as being at least as safe and robust as would have been required by any of the existing Rules
  • To fully embrace the intentions of the anticipated IMO requirements for goal based new construction standards.

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csr benefits to the industry
CSR - Benefits to the industry
  • Greater transparency of the technical background to the Rules
  • Reduced cost for ship yards by relating to one set of structural Rules only
  • All IACS societies will cooperate to maintain a single Rule set
  • Competition will be focused on service level covering
      • pre-contract,
      • plan approval,
      • newbuilding supervision
      • Ability to quick and efficient problem solving during ship in operation (SIO)
  • No competition on scantling requirements and Rule standard

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dnv ambitions
DNV - Ambitions
  • To be the best software supplier for CSR. The CSR Bulk software will reflect the experienced gained by the successful CSR Tank Software already recognized by users worldwide.
  • To be the preferred discussion partner for owner’s seeking to contract CSR vessels.
  • To be the preferred partner for yards and designers developing CSR vessels. Introducing ship yards and designers world wide to the new rules, where among extensive software training and rule background explanation are offered.
  • To be perceived as the most proactive and problem solving class society through genuine interest and gained knowledge about owner’s operational challenges.

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iacs common structural rules6
IACS – Common Structural Rules

IACS Common Structural Rules for Bulk Carriers L ≥ 90m and above

IACS Common Structural Rules for Double Hull Oil Tankers L ≥ 150m and above

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dnv csr bulk implementation schedule
DNV CSR Bulk - Implementation schedule

1 Apr 2006

1 Jan 2005

15 Feb 2006

3 Apr 2006

14. Dec 2005

CSR adopted by IACS Council

DNV software test release CSR Bulk carrier Rules

CSR Effective

DNV software release CSR Tanker Rules

DNV offer design review according to CSR

DNV software release CSR Bulk carrier Rules

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csr harmonization
CSR - harmonization
  • Short term harmonization prior to adoption by IACS
  • Long term harmonization

Implementation and

industry comments

Detailed harmonization plan

Feedback period

Harmonized CSR into force

Harmonization work within IACS

2006

2008

2009

2010

2007

2011

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csr bulk application
CSR Bulk - Application

Applicable for Bulk Carriers with L ≥ 90 m signed for construction after 1 April 2006

where:

Bulk Carrier is a sea going self-propelled ship which are constructed generally with single deck, double bottom, hopper side tanks and with single or double side skin construction in cargo length area and intended primarily to carry dry cargoes in bulk.

  • L < 350 m
  • L / B > 5 m
  • B / D < 2.5 m
  • CB ≥ 0.6

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csr bulk carrier in general
CSR Bulk Carrier in general

CSR

Not CSR

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csr bulk questions and answers
CSR Bulk – questions and answers
  • If a contract signed prior to 1st of April 2006 but construction will not commence until 2007?
    • Ships or series of ships signed for construction prior to 1. of April 2006 is not subject to CSR even if the construction is taking place later than 1st of April 2006. Such ships will be subject to current DNV Rules.
  • What if a ship building contract, signed prior to 1st of April 2006, includes options for additional ships, to which rules should the optional ships be constructed?
    • Options included in contracts signed prior to 1st of April 2006 is not subject to CSR if the option is exercised within a year of the initial contract signing.
  • What if a ship building contract, signed before 1st of April 2006, is amended, to which Rules should the additional ships be constructed?
    • Amendments is subject to the Rules in force at the date of signing the amendment. If the amendment is signed on or after 1st of April 2006, the ships are subject to CSR.
  • What about SOLAS XII “Additional safety measures for bulk carriers” requirements which come in to force July 2006?
    • For a vessel subject to CSR, SOLAS XII is automatically covered.
    • For vessels not subject to CSR, but subject to DNV Bulk Carrier Rules and with keel laying on or after 1st of July 2006, the SOLAS XII requirements are to be handled separately.

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csr bulk questions and answers12
CSR Bulk – questions and answers
  • Will vessels complying with DNV Nauticus(Newbuilding) meet the criteria of the CSR?
    • No. For the Nauticus(Newbuilding) design parameter is 20 years World Wide while 25 years North Atlantic is applied in the CSR. In addition, different yielding and buckling criteria is applied in CSR.
  • Will it be possible to modify an existing DNV Nauticus(Newbuilding) approved vessel to comply with the new CSR criteria?
    • Such modification would most likely enforce replacement or modification of key structural members. It is unlikely that such modifications could be considered economically feasible.
  • What would be involved to upgrade and exciting CSR sized design to meet the CSR criteria's?
    • Based on present experience, an increase in steel weight of 2-4% and up to 7-9% is expected depending on the original design basis. E.g. a IACS URS25 compliant vessel will normally fall within the first category.
    • DNV is currently cooperation with mayor bulk carrier designers to assist in upgrading their designs to meet CSR.

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csr bulk questions and answers13
CSR Bulk – questions and answers
  • Will a design already reviewed and approved as meeting the CSR by another IACS member be accepted by DNV?
    • As the design is already reviewed and approved by an IACS member, no significant difference in scantlings is expected. However, in order to verify such expectation, DNV will carry out full plan approval. If discrepancies are revealed this will be addressed in the appropriate IACS forum.

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csr bulk class notations
CSR Bulk – Class notations

X1A1 Bulk Carrier ESP CSR BC-A {allowed combination of specified empty holds}

➙for Bulk Carriers L > 150m designed to carry dry bulk cargoes of cargo density 1.0 t/m3 and above with specified holds empty at maximum draught. This notation implies that the ship is designed for alternate loading.

{maximum cargo density (in t/m3)}

➙ if the maximum cargo density is less than 3.0 t/m3

GRAB [X] ➙ minimum X = 20 t unladen grab, mandatory

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csr bulk class notations15
CSR Bulk – Class notations

X1A1 Bulk Carrier ESP CSR BC-B

➙for Bulk Carriers L > 150m designed to carry dry bulk cargoes of cargo density 1.0 t/m3 and above with all holds loaded . This notation implies that the ship is primarily intended for homogenous loading.

{maximum cargo density (in t/m3)}

➙ if the maximum cargo density is less than 3.0 t/m3

GRAB [X] ➙ minimum X = 20 t unladen grab, mandatory

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csr bulk class notations16
CSR Bulk – Class notations

X1A1 Bulk Carrier ESP CSR BC-C

➙for Bulk Carriers L > 150 m designed to carry dry bulk cargoes of cargo density less than 1.0 t/m3. This notation implies that the ship is limited to light cargo in homogenous loading condition.

{GRAB [X]} ➙ optional grab notation

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csr bulk class notations17
CSR Bulk – Class notations

X1A1 Bulk Carrier ESP CSR

➙for Bulk Carriers 90 < L < 150.

These ships have no minimum conditions. They are designed according to the loading conditions in the loading manual.

{GRAB [X]} ➙ optional grab notation

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csr net scantling approach

In Service

Design

Wastage

Allowance

Corrosion

Addition

Predicted corrosion

in 2.5 years (0.5 mm)

Required

Net

Thickness

Required

Renewal

Thickness

Annual

Thickness

Measurements

CSR – Net scantling approach

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csr corrosion additions
CSR – Corrosion additions
  • Corrosion addition determined based on the environment to which the structural member is subjected.
  • E.g.
    • tc1, exposed to sea water = 1.0mm
    • tc2, water ballast tank in general = 1.2 mm
    • treserve, maximum thickness diminution in 2.5 years = 0.5 mm
  • Total corrosion addition:
    • tc = Roundup0.5(1.2 + 1.0) + 0.5 = 3.0 mm

tc2

tc1

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csr corrosion additions20

Upper Deck:

TAsBuilt : 21.0 mm

JBPcorr all : 4.0 mm

DNVcorr all : 4.2mm

TS TK Bottom:

TAsBuilt :16.0 mm

JBBcorr all : 4.0 mm

DNVcorr all : 3.5 mm

TS TK Side shell:

TAsBuilt : 21 mm

JBPcorr all : 3.5 mm

DNVcorr all : 4.2 mm

Side Shell:

TAsBulit : 17.0 mm

JBPcorr all : 3.5/4.0 mm

DNVcorr all : 3.0 mm

Hopper:

TAsBuilt : 17.0 mm

JBPcorr all : 5.5 mm

DNVcorr all : 3.4 mm

Inner Bottom:

TAsBuilt : 20.5 mm

JBPcorr all : 5.5 mm

DNVcorr all : 4.1 mm

Side Shell Hopper:

TAsBuilt : 15.5 mm

JBPcorr all : 3.0 mm

DNVcorr all : 3.1 mm

Outer Bottom:

TAsBuilt : 16.0 mm

JBPcorr all : 3.0 mm

DNVcorr all : 3.2 mm

Outer Bottom:

TAsBuilt : 18.0 mm

JBPcorr all : 3.0 mm

DNVcorr all : 3.6 mm

CSR – Corrosion additions

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csr environmental assumptions
CSR – Environmental assumptions
  • 25 years design life
    • Today the common practice is 20 years
    • Resulting in increased corrosion additions
    • Slightly higher design loads
  • North Atlantic environmental conditions
    • Fatigue the damage in North Atlantic is about twice the damage of World Wide trading

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global ch model criteria
Global CH model - Criteria
  • Yield check
  • Buckling check of elementary plate panels
    • Shear buckling
    • Longitudinal buckling
    • Transverse buckling
    • Bi-axial buckling
  • Relative deflection between the double bottom and TBHD

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refining method for yield check
Refining method for yield check

EITHER:

Refined areas can be directly included in FE model used for the global cargo hold analysis

OR:

Detailed stresses in refined areas can be analysed by separate sub-models

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fatigue assessment of primary structures
Fatigue assessment of primary structures

Primary members subject to fatigue strength assessment

In addition, hatch corners. Stress concentration factors for hatch corners established by formulas.

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fatigue assessment of stiffeners
Fatigue assessment of stiffeners
  • Connection of stiffeners with web frames and transverse bulkhead.
  • Stiffener’s end connections to be analyzed:
    • Ordinary stiffeners in double side spaces
    • Ordinary stiffeners in upper and lower wing tank
    • Ordinary stiffeners in double bottom
  • For typical stiffener’s end connections tabular values for stress concentration factors have been established.

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