introduction to csr bulk_internet_tcm4-284042

7/31/2019 Introduction to Csr Bulk_internet_tcm4-284042

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Common Structural Rules(CSR) for Bulk Carriers

An Introduction


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Version Slide 209 May 2006

Scope of Rule Developments

CSR Bulker Carriers

- Complete set of Structural Rules for SSS and DSS Bulk

Carriers

- Length greater than or equal to 90m

CSR Oil Tankers

- Complete Set of Structural Rules for Double Hull Oil

Tankers

- Length greater than or equal to 150m


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Summary of CSRs

Jun 2004 1 Jan 2005

1st Draft

available toPublic

2nd Draft CSR

available to

Public

30 Sep 200515 Apr 2005

Published

15 Jan 2006

CSREffective

1 Apr 2006

CSRAdopted

1 Jan 2006

Industry comments6 months

Industry comments5 months

3rd

DraftCSRB

ulk

FinalDraftCSRB

ulk


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Major modifications of bulk carriers rulesafter the first draft

Larger uniform corrosion wastage allowances for transverse bulkheads and side

shell in line with 95% probability of non-exceedance (instead of 90%)

Thickness rounding procedure is modified, due to harmonisation between CSRTank and CSR Bulk

Harmonisation of Ships in Operation requirements between CSR Tank and CSRBulk

Rewritten FEM procedure: Finite element models are now only three holdsmodels, with modified boundary conditions to provide same results betweendirect and superposition methods

Modification of loading cases to be considered in Direct strength analysis

Compliance with new SOLAS requirements for flooding of DSS bulk carriers

Torsional loading to be considered for the hatch corners

Mandatory GRAB notation for grab loading and steel coil requirements


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CSR Expected way forward for IACSCommon Structural Rules

Feedbackperiod

2006 2007 2008 2009 2010 2011

Harmonization

work within IACSImplementationHarmonization

planHarmonized

CSR into force

Long term harmonization

External industry hearing


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What is CSR?

Rules covering structural requirement for Bulk Carriers and Tankers

A Rule set utilising state of the art computational methods for moreextensive direct calculations

Vessels built to CSR shall have overall safety of the hull structureequivalent to or better than that currently achieved by present rules

Safety

level

IACS CSR

Individual societyRules

Requirements

Safety level exceeding any IACS members existing Rules.


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The IACS Common Structural Rules covers

IACS Common Structural Rules for Double HullOil Tankers L 150m and above

IACS Common Structural Rules for BulkCarriers L 90m and above


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Why CSR?

To obtain control over the minimum safetylevel during the operation phase

To eliminate competition between classsocieties with respect to structuralrequirements and standards

To employ the combined experience and

recourses of all IACS societies to develop asingle standard, or set of Rules

To ensure that a vessel meeting this newstandard will be recognised by the industryas being at least as safe and robust aswould have been required by any of theexisting Rules


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DNVs commitment to support the industry

DNVs well established Nauticus Hull program has undergone a major

upgrade to provide efficient support for the new Rules.

An extensive training program has been implemented for all approvalunits enabling our staff to be well prepared to provide efficient and local

support

Offer training programs to designers and yards

Offer assistance and design reviews for the purpose of upgrading existingdesigns to comply with CSR

Offer pre contract service in general


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Why software support for the new Rules is so critical

The new rule requirements introduce a radical shift towards more

computerisation of the rule formulations and structural assessment.

Hence, good software support is critical for any Class to providetimely and rational support to ship-owners as well as designers andshipbuilders. Efficient software contributes to ensure safe design whileshortening the design time.


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Nauticus Hull for CSR Bulk - compartmentplan and loads shared among all applications

Easy and efficient to analyse many cross sections in Section Scantlings according to theCSR Bulk prescriptive rules:

Hull girder requirements

H-ULS (hull girderultimate capacity)

Yielding- Local pressures

- Intact and flooding

Buckling

- DIN Standard

Steel coil

- Line loads

Grab loading

Minimum scantlings


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Nauticus Hull CSR Bulk - Direct StrengthAnalysis, FEA

New Workflow Manager

New tool for definingcompartment plan and loads

New efficient FE tool that willshorten design time SESAMGeniE

- Modelling of cargo hold modeland local models

- Meshing- Automatic Rule loads import

(interfacing with newcompartment and loads tool)

- FE solver integrated SESAMSestra

- Integrated PostProcessing/Code Checking(Buckling Check, Yield Checkand deformation Check)

SESAM Xtract for detailedresult presentation and stressevaluation

Other SESAM modules(Submod, Cutres)


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Does CSR provide any benefits to the industry?

Greater transparency of the technical background to the Rules

All IACS societies will cooperate to maintain a single Rule set

Competition will be focused on service level, i.e. newbuilding and SiO support

The net scantling principle, i.e. the minimum allowable scantlings during theoperational lifetime of the vessel is defined as the net scantlings for thenewbuilding design

Reduced cost for ship yards by relating to one set of structural Rules only

The intention of the new Rules is to encourage the design and construction ofrobust tankers and bulk carriers and to eliminate competition on scantlings

The minimum fatigue design life is set to 25 year North Atlantic environment.

The corrosion additions that have been established takes into account thelocation and the environment to which the structural members surface issubjected

Stringent and clarified requirements to critical areas


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Net scantling approach

Net scantling to be maintained through the ship life

Corrosion addition corresponding to the corrosive environment added on

top of the net thickness

Renewal thickness to be identified on drawings at newbuliding stage

Thic

kness

New building In service

Required net

thickness

Corrosion additionincluding owners extra Wastage allowance

Renewal thickness

2.5 year diminution


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Critical areas Stringent and clarifiedrequirements

Longitudinals in way of the

hopper tank at shell are mostexposed to fatigue cracks.

CSR require 25 years

operational life in NorthAtlantic.

Increased safetyfactor for single side

shell according toSolas XII


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Fatigue check of main frame connection to hopper sloping plating and improved steelgrade for bracket and adjacent side plating


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Fatigue check of inner bottom

plating connection with lower stooland hopper sloping plating


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Transverse bulkhead and lower stool

Mandatorystrengthening for grab

loading

Fatigue check of lowerstool and corrugatedbulkhead connection


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IACS UR S21 (Rev. 4)for Hatch Covers and

Hatch Coamings


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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 constructedgenerally with single deck, double bottom, hopper side tanks and withsingle or double side skin construction in cargo length area and intendedprimarily to carry dry cargoes in bulk.


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Typical Bulk Carrier Class notationbefore CSR

1A1 Bulk Carrier ESP Nauticus(Newbuilding) BC-Aholds 2,4,6 and 8 may be empty

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 foralternate loading.

IB(+) is optional


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Typical Bulk Carrier Class notation after CSR

1A1 Bulk Carrier ESP CSR BC-A GRAB(20) holds 2,4,6and 8 may be empty

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 foralternate loading.

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


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