Sniped stiffeners, requirement to buckling capacity - please see attachment for full query as it included diagrams and equations.

Transcription

1 IACS Common Structurl Rules Knowledge Centre Bulker Q&As nd CIs on the IACS CSR Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 161 6/3.4.. Question Stiffeners 007/6/11 A point is not cler while clculting the bending moment M0. Wht must be done when (cf - pz) is negtive or null? The requirement [4..3] should be pplied both to ordinry stiffeners subjected or not to the lterl pressure. When this requirement is fullfilled for stiffeners subjected to lterl pressure, the term (cf-pz) which ppers in the clcultion of M0 in [4..] becomes greter thn 0. In ddition, requirements [4..1] nd [4..] pply only to ordinry stiffeners subjected to the lterl pressure /1/.5.1 Question welded sherstrke 006/9/7.5.1 Welded sheerstrke The net thickness of welded sheerstrke is to be not less thn the ctul thicknesses of the djcent m width side plting, tking into ccount higher strength steel corrections if needed. In this item, does the ctul thickness men ctul gross thickness or ctul s-built thickness? Is the word 'net' omitted between 'ctul' nd 'thicknesses' s 'the ctul net thicknesses'? The ctul thickness of the djcent side plting is to be understnd s being the ctul net thickness, equl to (ts built - tc). 04 ttc Ch 6 CI Stiffeners 007/6/11 Sniped stiffeners, requirement to buckling cpcity - plese see ttchment for full query s it included digrms nd equtions. )Section 3 covers buckling of ordinry stiffeners nd stiffened pnels. Therefore sniped buckling stiffeners re subject to Ch. 6 Sec. 3 [4]. b)no. Ch.6 Sec. [1], [] nd [3] re pplicble to ordinry stiffeners nd [4] is pplicble to web stiffeners. Buckling stiffeners s shown re subject to 1.Ch. 3 Sec.6 [5..1].Ch. 6 Sec. [4.1.] 3.Ch. 6 Sec.3 [4] Y 1 6/ Question side shell plting 006/11/ There re some cses where the side shell plting djcent to sheer strke includes single side prt nd is incresed due to the buckling nd hull girder sher strength.obviously, its reinforcement is not necessry for sheer strke, then plese revise the sentence s follows:"...is to be not less thn the required thickness of the djcent m width side plting, which is clculted ccording to Ch.6, Sec.1,..." Generlly, when the side shell plting djcent to sheer strke includes single side prt nd is incresed due to the buckling nd hull girder sher strength, it is lso the cse for the sheer strke, which is locted bove. Consequently, we see no reson to modify this requirement. 13 6/...1 Question hull girder 007/1/11 We consider tht this requirement hs been introduced tking into ccount sher lg. However, there re some cses where the ttched plting is incresed due to the buckling of the plting nd hull girder sher strength. Therefore we would like to sk you to revise the sentence s follows: "The net thickness of the web of ordinry stiffeners, in mm, is to be not less thn the greter of: 40% of the net required thickness of the ttched plting, which is clculted ccording to Ch.6, Sec.1." We gree with the modifiction proposed in the originl question: "The net thickness of the web of ordinry stiffeners, in mm, is to be not less thn the greter of: - t = L - 40% of the net required thickness of the ttched plting, to be determined ccording to Ch.6, Sec.1. nd is to be less thn times the net required thickness of the ttched plting." We will consider the Rule chnge proposl. Pge 1 of 31

2 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 14 6/..3 Question PMA 006/1/13 If pplying this requirement to longitudinl PMA hving wide width, the required scntlings become to be very hevy. This rule seems to be buckling requirement. Since t lest longitudinl structurl members, such s deck plting, skin plting, longitudinl bulkhed plting, inner bottom plting nd longitudinl stiffeners ttched to them, re to be complied with Ch.6, Sec.3 Buckling & Ultimte Strength of ordinry Stiffeners nd Stiffened Pnels, it is not necessry to pply this rule to them. We would like to sk you to revise the rule tking into ccount the bove. Such longitudinl PMA hving wide width should comply with the requirement of [.3], where it is pplicble considering the configurtion of the stiffener. In cse the stiffener should not comply with the requirement of [.3] or [.3] should not be pplicble to the stiffener, such longitudinl should be modeled by shell elements in FEA nd its yielding strength nd buckling strength should be verified s primry supporting member. 15 6/ Question BWE 006/1/8 The net required section modulus [3..3] of side frmes in holds intended to crry bllst wter is excessive thn our experience nd pproximtely twice the vlue required by [3.3.1].The cuse of the bove is the difference in position to be ssessed.in [3.3.1], the position to be ssessed is the mid spn of side frme. And the position to be ssessed in [3..3] is the fixed ends.according to [3.3.3], the required section modulus t ends of side frme is to be twice of the required section modulus t mid spn.therefore we would like to sk you to revise the rule s follows:cse A - [3..3] "m=0 for side frmes of single side bulk crrier"orcse B - [3.3.1]To dd the following:"...the net section modulus t lower nd upper brcket" We conclude tht there is no need to chnge the rule formul ccording to the following reson. With our clcultions, we hve not seen this rtio of between the ppliction of [3..3] for side frmes in holds intended to crry bllst wter nd [3.3.1].It would be interesting to hve more detiled informtion on the comprtive clcultion to check tht ll prmeters re correctly tken into ccount, nd in prticulr the spn, which is not the sme in both requirements. In [3..3], the spn is defined in Ch 3, Sec 6, [4.], i.e. by considering reduction of spn due to brckets; nd, In [3.3.1], the spn is defined in Ch 3, Sec 6, Fig 19, i.e. by considering no reduction of spn due to brckets.therefore, the text is kept s it is. 16 6/ Question pressure formul 006/11/ The required scntlings by this rule is excessive thn our experience. In the formul, counter pressures cting on side longitudinls, hopper / top side longitudinls nd bcking brckets re ignored. Thus the rule brings hevy scntlings. We would like to sk you to revise the formul in which counter pressures re tken into ccount. If it is difficult, n lterntive nlysis such s direct clcultion should be permitted. The pressures to be considered in this formul re the pressures t mid-spn of the side frme. In ddition, the differentil pressures, if ny, re to be considered. Also Included in Corrigend /.3.4. Question direct clcultion 006/11/3 The required scntling nd the mteril by this requirement re excessive thn our experience.an lterntive nlysis such s direct clcultion should be permitted. From our experience, we hve not seen excessive scntlings. We would like to hve more informtion on this "excessive" vlues. In ddition, to ccept tht lterntive nlysis such s direct clcultion re permitted is generl question for the totlity of CSR (oil or bulk). This should be discussed s generl mtter. Pge of 31

3 IACS Common Structurl Rules Knowledge Centre KCID No. 68 Ref. Type Topic 6/ Question FEM buckling Dte completed 006/11/30 Question/CI The uthor requests chnges nd defines e3 & ky s equl to 1. As fr s we concern both kx (for longitudinlly loded plting) nd ky (for trnsversely loded plting) is defined in Tbles & 3(for curved plting) nd e3 is well defined in Tble 4. IACS's proposed dditionl definition confuses the issue. Propose to leve text s it ws prior to errt Answer Reference is mde to: Additionl informtion ccording to "Corrigend 1, My 006", Ch 6, Sec 3, [3.1.]: The following three lines re the originl text: Ech term of the bove conditions must be less thn 1.0. The reduction fctors kx nd ky re given in Tb nd/or Tb 3. The coefficients e1, e nd e3 re defined in Tb 4. This ws the Add. inf.: For the determintion of e3, ky is to be tken equl to 1 in cse of longitudinlly frmed plting nd kx is to be tken equl to 1 in cse of trnsversely frmed plting. We dded this dditionl informtion due to severl requests from other clssifiction societies, how to clculte e3, becuse in the buckling ssessment of plte field in trnsverse section nlsys only hull girder bending nd sher stress hve to be tken into ccount (Ch6, Sec3, 3.1.). Therefore the kpp prmeter of lod norml to the hull girder bending stress hs to be set to "1" to clculte e3 ccording Tble 4. In cse of pressure loded bilge plte, the pressure induced circumferentil stress hs to be neglected for trnsverse section nlysis. In FEM bsed buckling nlysis this stress hs to be tken into considertion nd the complete interction formul of 3..4 hs to be used. The dditionl informtion, given in "Corrigend 1, My 006", is kept becuse this is complete interction formul of 3..4 hs to be used. The dditionl informtion, given in "Corrigend 1, My 006", is kept becuse this is universlly vlid for the trnsverse section nlysis. Attch ment 76 6/.3.3 Question side frmes 006/11/ The requirement of this rule for side frme seems to be excessive. The section modulus of side frme of CSR is bout twice of URS5. From our experience, we hve not seen excessive scntlings. We would like to hve more informtion on this "excessive" vlues.it would be interesting to hve more detiled informtion on the comprtive clcultion to check tht ll prmeters re correctly tken into ccount. 311 ttc 6/ Question ve stress 006/1/1 How to determine the supporting re of the pressure to clculte the compressive stress? If the CSR Bulker Rules hs not described, the proposl in the ttched file could be tken into considertion. There my be vrious rrngement of pillrs nd other supporting structures. Then supporting re should be determined on cse by cse bsis. Y 318 6/ Question buckling rtio 006/1/1 In the first formul in Ch 6, Sec 3, 3..4, we re worried bout the effect of the third term with B fctor which mkes the buckling rtio higher in cse when one side is in tension thn in cse when both sides re in compression.could you confirm tht the formul is correct? We confirm tht the formul is correct, with B fctor defined in Tble ttc 6/.3.4. Question brckets 007/1/1 The vlue of the net connection re of upper nd lower brckets to the ith longitudinl stiffener supporting the brcket, obtined from Ch 6, Sec, [3.4.]) my be times the ctul vlue. Such lrge increse my imply the following risks: - Uselessly reinforce brcket thickness. - Uselessly sk for web stiffener connected to longitudinls. - Uselessly extend brckets which could interfer with the PMA rrngement. Plese forwrd us the bckground of formul in [3.4.1] nd [3.4.]. This requirement is coming from work of IACS WP/S t the time of fourth revision of UR S1, in 00/003. A Technicl Bckground explining the formule of Ch 6, Sec, [3.4] of CSR for bulk crriers is herewith enclosed. The clcultion is on the conservtive side (i.e. higher prt of the end-fixing moments is trnsferred by trnsverse supporting webs), but not unduly, nd we relly don't think chnge is techniclly justified. The only interprettion tht could sfely be done looking t the derivtion of the formul in [3.4.] is to replce the provided net section modulus wi by its minimum required vlue to comply with [3.4.1]. Y Pge 3 of 31

4 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 37 6/ CI inertil pressure 007/1/ Regrding the internl inertil pressure p due to liquid to be pplied, our undestnding is tht such pressure re those of: - Double Bottom pressure lone cting on bottom longitudinl. Plese confirm? - Topside tnk bllst pressure lone cting on side nd deck longitudinl. Plese confirm? - Blnce of Double Bottom pressure nd Deep Tnk bllst pressure cting on Inner Bottom longitudinl of Deep tnk. Plese confirm? - Blnce of Top side tnk bllst pressure nd Deep Tnk bllst pressure cting on top side sloping plte longitudinl. Plese confirm? In ddition, in no cse pressure p cting on wtertight floors of double is not to be considered, neither should it be considered for wtertight prt of bulkheds belonging to wing tnks. Plese confirm? Our interprettion is tht the pressure to be considered should be only internl inertil pressure cting on the longitudinl. For better understnding, we will consider the editoril correction of the definition of p in [4.1.3]. Also Included in Corrigend / & 6/..5.4 Question uniform lods 007/1/1 In [.7.4] of Ch 6, Sec 1 for plting nd in [.5.4] of Ch 6, Sec for ordinry stiffeners, for steel coil lod with dunnge more thn 5, it is stted tht the inner bottom my be considered s loded by uniform distributed lod. But CSR hs no definition for uniform lods. So such definition of uniform lods should be introduced CSR. A definition of uniform lods on inner bottom will be included in CSR for bulk crriers. 333 ttc 3/6.5. 6/.. 6/..3 6/4.1.5 Question Web Stiffener 006/1/18 Web stiffeners of primry supporting members: (1) Becuse there is no definition for primry supporting member, the mening of web stiffener of primry supporting member itself is unidentified. Plese clrify the definition of primry supporting members. () Plese see the ttched summry tble bout rule pplictions for web stiffeners of primry supporting members bsed on our understnding. It shows tht which requirements should be pplied to web stiffeners. Plese confirm. (3) We lso would like to confirm tht whether the web stiffeners fitted on wtertight girders, e.g. wtertight centre girder nd floors, should be pplied to the both requirements for primry supporting members of Chpter6/Section4 nd for ordinry stiffeners of Chpter6/Section or not. (4) If there is ny needs to stisfy both requirements for primry supporting members nd for members subject to lterl pressure, I would like to know whether the web stiffeners fitted on the wtertight bulkheds in the topside tnks nd bilge hopper tnks re treted the sme or not. (1) Primry supporting member re defined s: members of the bem, girder of stringer type which ensure the overll structurl integrity of the hull envelope nd tnk boundries, e.g double bottom floors nd girders, trnsverse side structures, web frmes/diphrgms in hopper side tnks, topside tnks, lower stools nd upper stools, side stringers, horizontl girders/trnsverse web frmes, htch side/end coming. () The requirements in Ch 6, Sec, [.] dn [.3] re not pplicble to web stiffeners but to ordinry stiffeners, The only requirements pplictle to web stiffeners in CSR for bulk crriers re the following ones:- Ch 3, Sec6 [5..1] for the net thickness of such stiffeners, which refers to the minimum net thickness of the primry members on which they re fitted, i.e. to Ch 6, Sec 4, [1.5.1], nd - Ch 6, Sec [4] for the net scntlings of web stiffeners of primry supporting members. (3) The sme requirements s stted in () bove pply to web stiffeners fitted on wtertight side girders, centre girders nd floors, i.e. Ch 3, Sec 6, [5..1]for the net thickness of such stiffeners ( nd so Ch 6, Sec 4, [1.5.1] nd Ch 6, Sec, [4]. (4) See our comment in (1) s we consider tht stiffeners on these bulkheds re considered s ordinry stiffeners nd not s web stiffeners. Y Pge 4 of 31

5 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 344 Ch.6, Appendix 1/1.3.4 Question Corrugted BHD 007/5/14 The current requirement is only considering the buckling strength from the locl bending stress s it is only tken the mximum verticl stress without sher component. Therefore, the pnel size is only tken s b times b for fce plte nd b times b for web plte. However it should be noted tht the buckling strength should be considered not only from the locl bending stress but from the globl bending nd sher stress. It is expected tht the higher sher stress would be induced t the connection of corrugted bulkhed to side shell, hence the sher buckling should lso be tken into ccount. To ssess the sher buckling, the pnel size should be tken seprtely from bove, i.e. full length pnel from top of lower stool to bottom of upper stool nd the sher stress to be tken s men sher stress of the lrge pnel. If FE nlysis derives signifcnt sher stress in fce pltes of corrugted bulkheds you my tke this stress into considertion ccording cse b), described in Text 6/ Appendix 1/1.3.4 Question The Mximum Verticl stress 007/7/ The current requirement sttes tht the mximum verticl stress in the elementry plte pnel is to be considered in pplying the criteri. This results the severe requirement when the qulity of the mesh ws poor t the edge of corrugtion where the connection of other structures to corrugtion is reltively complex. To pply the mximum verticl stress to the elementry plte pnel is considered unrelistic. This should be enhnced to be more prcticl. Assuming b x b or b x b buckling field (depending on the considered re) you my derive the verticl stress s n verge vlue of elements inside this re. Lower prt of the web pltes prone to include bd shped elements or tringulr elements my be neglected. Ech re with different thickness is to be considered nd checked seprtely. 346 Chp 6/ Appendix1 /1.3.4 Question The Edge constrint fctor 007/3/9 The current requirement, the edge constrint fctor, F1 = 1.1. This should be 1.0. As the correction fctor F1 is not used for the buckling lod cses 1 nd 5, the lines "F1=1.1 is to be used" in () nd (b) of re not necessry. We will consider the editoril correction. 356 ttc 6/ Question Modulus 007/3/16 Questions on the requirement for mid-spn sectionl modulus. See the ttched. () Yes, ps nd pw in the formuls in Ch.6 Sec. [3.3] re pressures in intct condition. (b) Yes, Ch.6 Sec. [3..3] is to be pplied to side frme only in wy of bllst hold in hevy bllst condition. (c) Q1: The required section modulus by the formul in Ch.6 Sec. [3..3] should be pplied to whole spn of side frme. Plese note tht while the spn l in Ch.6 Sec. [3.3.1] is to be determined without considertion to end brckets ccording to Ch.3 Sec.6 Fig.19, the spn l in Ch.6 Sec. [3..3] my be with considertion to end brckets s specified in Ch.3 Sec.6 [4.]. (d) Q: The required net section modulus t end brckets is to be not less thn twice the greter of the net section moduli required for the frme mid-spn re obtined from Ch.6 Sec. [3.3.1] nd Ch 6 Sec. [3..3] for bllt hold. Y 357 6/ Question Web Stiffener 007/5/14 Which vlue of k1 is to be used for web stiffener on wtertight primry supporting member? For web stiffener on wtertight primry supporting member, i.e. with full collr plte, k1 is to be tken equl to 0.. Pge 5 of 31

6 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 360 ttc Tble 6.3. Question Rule Chnge 007/7/1 Ch6 Sec3 We get different results for LC5 in Tble depending on whether we denote the longer side b nd the shorter side lph*b, or vice vers. This is n unexpected result. We suspect this is cused by n inccurte definition of b. The definition of b should be similr to the definition of l in CSR Tnk. We propose the following definition, which is in line with CSR Tnk: b: length in mm, of the shorter side of the plte pnel for Cses 1 nd, or length in mm, of the side of the plte pnel s defined for Cses Further we suspect the formul for reference stress sigm_e in the List of Errt of April 006 is incorrect. b, s defined bove, should be used for the clcultion, not b'. This mens the formul s printed in the Rules of Jnury 006 is correct. By mking the bove described modifictions we void the problem for LC5, nd we re lso in line with CSR Tnk. Plese comment. Your conclusions re right. We will prepre rule chnge proposl s follows: Definitions in Symbols : Length in mm of the longer side of the prtil plte field in generl or length in mm of the side of the prtil plte field ccording Tble, BLC 3-10 b: Length in mm of the shorter side of the prtil plte field in generl or length in mm of the side of the prtil plte field ccording Tble, BLC 3-10 In ccordnce with these definitions of nd b the definition of the reference stress S_e of the CSR for Bulk Crrier 006 is correct. We will reject the definition, given in the Corrigend 1. "Note: IACS Council expedited the rrule chnge required s result of this question nd on 19 July 007 greed tht the correction in the ttched file should be mde to Ch.6, Sec.3 Symbols." Also Included in Corrigend 5 Y 367 6/ & 6/ Question Flooding Requirement s 009/9/4 The definition of sig-x is uncler for longitudinl members in flooding condition. The MSW,F in Ch 4 Sec 3 [.4] ssumes flooding of individul crgo hold nd is required only for BC-A nd BC-B ships. Does the sme MSW,F pply to ny dry comprtment, for instnce, inner side nd duct keel in double bottom spce? How do we pply MWH,F nd ny of the lod combintion fctors? 1) When hold flooding is considered for locl scntlings check of plte or stiffener, MSW,F, MWV,F nd MWH,F re to be used in lieu of MSW,MWV nd MWH respectively for clculting sigm_x by the formuls in Ch.6 Sec.1 [3.1.5] nd Ch.6Sec. [3.1.5], where MWH,F=0.8MWH. However in this cse the sme lod combintion fctors CSW, CWV nd CWH s those for intct condition re to be used. Notwithstnding the bove, for ship of length Ls <150m the sigm_x is to be clculted by the sme formul s tht in Ch.6 Sec.1 [3.1.5] or Ch.6 Sec. [3.1.5], s pplicble." ) When flooding of the comprtment other thn hold is considered, sigm_x is to be clculted by the sme formul s tht in Ch.6 Sec.1 [3.1.5] or Ch.6 Sec. [3.1.5], i.e, only intct conditions should be used to determine Sigm_x, s pplicble. This interprettion will be included in the Rules t future revision. 368 Ch 6 Sec & Sec Question Clcultion 007/3/0 In order to clculte sig-x for BC-C ships nd ships with length less thn 150 m, do we hve to clculte MSW,F by flooding individul crgo holds which is not required for longitudinl strength? Sigm x for intct condition is used. 369 Ch 6 Sec nd Sec.3..5 Question corrugted BHD 007/3/0 We ssume tht these requirements pply to stools of corrugted bulkheds with the design lod s given in Ch 4 Sec.6 [3..1]. Flooding lod given in [3.3] does not pply to the bulkhed stools. Plese confirm. Yes, your interprettion is correct. Pge 6 of 31

7 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 370 6/1.3.. &.3..5 Question Flooding Requirement s 009/9/4 The MSW,F is defined in Ch 4 Sec 3 [.4] by flooding individul crgo holds. If the sme design moment is pplied to ny dry comprtment such s duct keel, the flooding requirements my, ccording to our clcultion, give hevier scntlings thn the intct requirements. This mens tht the flooding requirements my hve to be pplied to ll structurl boundries s minimum. Plese explin. When flooding of the comprtment other thn hold is considered, sigm_x is to be clculted by the sme formul s tht in Ch.6 Sec.1 [3.1.5] or Ch.6 Sec. [3.1.5], i.e, only intct conditions should be used to determine Sigm_x, s pplicble. 37 6/3.6 Question corrugted BHD 007/3/9 Sher buckling of verticl corrugted bulkhed is required for BC-A nd BC-B only. The sme limittion is stted in [1.1. b)]. This is inconsistent to other requirements for corrugted bulkheds which pply to ll ships. Does this requirement pply to ll ships s well, sme s Sec 1 [3..3] nd Sec [3..6]? Plese explin. It is typo. The wordings "for BC-A nd BC-B ships" re delted from the text in Ch. 6 Sec 3 [1.1.] nd the title of [6]should be deleted. This editoril corrrection is included in "Corrigend ". Yes, it is typo error. The text of this requirement should be red s: 373 6/ Question direct clcultion 007/3/5 In ddition the primry supporting members for BC-A nd BC-B ships re to comply with the requirements in (3) nd (4)" The Sub-Section (4) is bout buckling strength of pillrs is this typo error?. For primry supporting members for ships hving length of 150 m or more, the direct strength nlysis is to be crried out ccording to the provisions specified in Ch 7, nd the requirements in [4] re lso to be complied with. In ddition, the primry supporting members for BC-A nd BC-B ships re to comply with the requirements in [3]. Also Included in Corrigend /4. Question Flooding Requirement s 009/9/4 This section pplies to primry supporting members in intct condition only. Do we not check primry supporting members on the boundries of dry comprtments ginst flooding lod, such s those on plne bulkhed t forwrd of foremost hold or ft bulkhed of ftermost hold? This is inconsistent to flooding requirements for locl pltes nd stiffeners in Ch 6 Sec 1 nd Sec covering ll ships. Plese explin. Your comments hve been noted nd further studies hve been mde to consider extending the requirements for flooding conditions, the outcome of which will be included in future revision of the Rules / Question Holds loded with steel coils 009/10/6 The results currently obtined show n importnt increse of the gross thickness for plting of hopper nd inner hull when pplying the formuls of Ch.6 Sec.1 [.7.3] under steel coils lods. Should this clcultion of hopper sloping plte nd inner hull plting for steel coils lods be performed? Your comment hs been noted nd this issue hs been ddressed in RCN No.1-3 to the July 008 Rules. Pge 7 of 31

8 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 38 6/ Question stiffeners 007/3/9 Could you plese confirm how to determine the reference point of Z cordintes of stiffeners when clculting the norml stress sigm_x of stiffeners which contribute to the hull girder longitudinl strength? Is it the sme s JTP? The reference point for stresses nd lods clcultions is t the bottom nd middle of its web, ie. where the stiffener joins the ttched plting. This is different to the CSR Oil choice which bse the reference point t the top / Question The Norml Stress Sigm_n 007/10/4 Could you plese confirm how to determine the norml stress sigm_n which is bsed on the xil stress clculted t the ttchment point of the stiffener to the plte? Is it the sme s JTP? We confirm tht: 1)the norml stress sigm_n is the xil stress of longitudinl stiffener which is clculted t the ttchment point of the stiffener to the plte, )it is the sme wy s JTP. 389 Tble 6.3. Question Sher Buckling 007/5/14 Cse 6 of Tble for sher buckling is pplicble only for d/<=0.7 nd db/b<=0.7. Then, how to clculte sher buckling where d/>0.7 or db/b>0.7? Plese dvise prticulrly on the following points: 1) Presume tht the formu of "r" yields conservtive results. If so, is it cceptble to use the formul of r lso for the cse of d/>0.7 or db/b>0.7? ) In cse of the pnel with lrge spect rtio with opening of d/>0.7 or db/b>0.7, plese dvise ny guidnce/criteri of sher buckling clcultion for the pnel with one edge free (similr to Cse 3 nd Cse 4 for xil compression). If cut out hs size beyond the limits of d_/<=0.7 or d_b/b<=0.7 only smll stripes re left beside the opening. The whole sher is trnsformed in S-shpe deformtion of the stripes. This behvior is not comprble to the ssumption, tht the elementry plte field cts s one buckling field. An extrpoltion of the formule of BLC 6 is not designted. Up to now we re not ble to provide user of the CSR for BC with such n dditionl buckling lod cse. 40 ttc 6/ , 6/1.3.., 6/.3.1.3, 6/.3..5 CI Flooding Requirements 007/7/1 3 Questions relted to flooding requirements in Ch.6, Sec.1 1 nd Question Q1: Your understnding is correct: Ch 6, Sec 1, [3.1.3] nd Sec, [3.1.3] will be revised, s editoril correction to The lterl pressure in flooded conditions pf is defined in Ch. 4 Sec. 6 [3..1]. Question Q: Ch 6, Sec 1, [3..] nd Sec, [3..6] re requirements coming from UR S18. The reference to the design resultnt pressure in Ch 4, Sec 6, [3.3.7] only is fully in line with UR S18. Consequently, there is no need to dd ny reference to [3.3.6]. Question Q3: Your understnding of the summry of flooding requirements should tke into ccount the nswer to question Q bove. Also Included in Corrigend 5 Y 408 6/1...1 Question scntling determintion 007/3/1 In the determintion of the minimum net thickness of side shell plting in prgrph [..1] of Chpter 6, Section 1, which drught is to be used in the formul? The moulded drught or the scntling drught? Since the moulded drught cn chnge during the ship's life, the drught to be used in the formul is the scntling drught /1...1 Question formul 007/3/ In the determintion of the minimum net thickness of side shell plting in prgrph (..1) of chpter 6, section 1, cn you recdefine more clerly the extent of side shell where the formul is to be pplied. The formul is to be pplied from the minimum design lowest bllst wterline midships to 0.5 Ts (minimum.m) bove Ts. Pge 8 of 31

9 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 418 6/.4.1. CI Net Sectionl Modulus of web Stiffeners 007/1/14 Ch.6 Sec. [4.1.] Net sectionl modulus of web stiffeners of primry supporting members. Should the net sectionl modulus be clculted with or without ttched plting? If the nswer is "with the ttched plte", then wht is the effective width to be considered? Plese consider clrifying the section. The net section modulus of web stiffener of non-wtertight primry supporting member should be clculted without the ttched plting. 419 Ch.6 Sec. Question Ordinry Stiffiners 007/4/5 Wht is the definition of ordinry stiffener? Are web stiffeners of primry supporting members to be considered ordinry stiffener? Web stiffeners of primry supporting members re not to be considered s "ordinry stiffeners". Plese see enclosed document "Ch6. Sec. 1 [.7.3] Steel coil loding on hopper plte.doc" regrding steel coil loding on inner side/hopper plte. 45 ttc 6/ &..5.3 CI Steel coil loding 009/10/6 Q1: Plese comment on enclosed document regrding ccelertion formultion for steel coil on hopper sloping/inner side. Plese note tht the hopper norml ccelertion clculted directly bsed on the fundmentl ccelertions is smller thn the rule ccelertions. Dependent on the term sin(lph-thet), the roll ccelertion will work towrds the grvity ccelertion. Plese note tht the ccelertion is sensitive to the definition of COG. The procedure to define COG should be clerly defined in the rules. With reference to IACS KC #380 plese consider bove ccelertion clcultions. Your comment hs been noted nd this issue hs been ddressed in RCN No.1-3 to the July 008 Rules. Y Q: DNV hve noted tht the results of eq. [.7.3] give very strict results for the hopper sloping plte. The thickness of the hopper sloping plte is in mny cses in excess of the requirement of the inner bottom. The force on the hopper is lrger thn the force for the inner bottom. This is cused by the Ck fctor which is 4 for tiers stowge. Could you plese give detils regrding the bckground of this term. According to our steel coil experts the stowge is, even though it is shored, quite flexible. Hve there been ttempted ny test to ccount for the mount of force tken by the hopper plting? Pge 9 of 31

10 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 457 6/.3..3 CI Formul 007/7/16 According #356 the spn "l" in the formul of CH6, Sec3, 3..3 hs to be clculted tking the brckets into considertion ccording CH3, Sec6, 4.. In cse of bllst crgo hold frme of SSS-BC the side frme brckets re not comprble to the ones shown in Fig. 3 of CH3, Sec6, The brckets of side frme elongte the side frme more thn tht they shorten it. How should we tke the brckets of side frme in bllst crgo hold into considertion? For the ppliction of Ch6, Sec, 3..3 in cse of bllst crgo hold frme of SSS-BC, the wy to consider the brckets is clerly defined in the fourth sketch of Fig of Ch3, Sec6, /3, 5/ CI Ordinry Stiffeners & Stiffened Pnels 007/7/13 Ch. 6 Sec. 3 Bucking & ultimte strength of ordinry stiffeners nd stiffened pnels. According to [1.1.] buckling ssessment of longitudinl mteril is not required for flooding conditions. According to URS 17 buckling check is required for flooding condition. Quote: S Strength criteri The dmged structure is ssumed to remin fully effective in resisting the pplied loding. Permissible stress nd xil stress buckling strength re to be in ccordnce with UR S11.Unqoute. The Ch. 5 Sec. HULS is clculting xil stress buckling of hull girder due to flooding bending moment. Q1. We ssume tht CSR fulfils URS17.5 by HULS check of Ch. 5 Sec.. Plese confirm Q. We ssume tht buckling ccording to Ch. 6 Sec. 3 need not be clculted in flooding condition s outlined in [1.1.]. Plese confirm. 1)Yes. Your ssumption is correct. )Yes. Your ssumption is correct. 470 ttc 6/ Question Compression Stress 008/7/ Wht kind of compression stresses hve to be used in the buckling check formule for the individul compression stresses in 3..4 of CH6, Sec3? We will consider the rule chnge proposl. Y 475 6/ CI Net Thickness of the Bilge plting 007/7/7 Ch. 6 Sec. 1 [.3.3]: This section requires tht the net thickness of the bilge plting is to be not less thn the ctul net thicknesses of the djcent m width bottom or side plting(..) Is this requirement referring to: 1. As built thickness;. Thickness required by Ch. 6; 3. All thickness requirements in CSR. (Ch. 7 FEM requiremtns, 9 sec. 1 Strengtheing of bottom forwrd etc). Plese dvise. This requirement is referring to the net thickness offered of the djcent bottom nd side plting. 483 ttc Tble RCP Buckling nd reduction fctors for curved plte pnels 007/8/8 Regrding the buckling nd reduction fctors for curved plte pnels in Ch 6, Sec 3, Tble 3, there is prtition line in the first column between buckling lod cses 1 nd 1b. However, in the originl GL rules, there is no such line, see ttched. This prtition line is likely to cuse incorrect vlues of Sigm x, hence should be deleted. Yes. This is typo. We will issue the "corrigend" soon. Also Included in Corrigend 5 Y Pge 10 of 31

11 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 493 ttc 6/ CI Correct ppliction of the formul with respect to pressure on ordinry stiffeners. A1. The requirement of Ch 6 Sec 4 [4.1.1] is provided for checking the scntling web stiffener nd web connection with ordinry stiffener. Therefore, the checking formul is provided s function of the pressure cting on the ordinry stiffener with coefficient depending on the web connection with ordinry stiffener. In cse of web stiffener ttched to floor in double bottom which is used for wter bllst, the pressure p is to be clculted s follows: A: Web stiffener nd the web connection with the bottom longitudinl: The considered pressure is the greter of: Ref. Ch. 6 Sec. [4.1.1] Q1: Plese dvice wht is the correct ppliction of the formul with respect to pressure on ordinry stiffeners:.externl nd internl pressures re to be considered seprtely. b.combined effect of pressures to be considered. (1) Pressure cting on bottom longitudinl due to externl se wter in full lod condition, or () Pressures cting on bottom longitudinl due to internl pressure due to bllst wter in double bottom tnk nd externl se wter in bllst condition, in line with Ch 6 Sec, /1/9 In cse of b.) plese dvice how to combine pressures Y (see ttched drwing) Q: We ssume correct interprettion of Web stiffener mid height is Web stiffener mid length. Plese dvise. B: Web stiffener nd web connection with the inner bottom longitudinl: The considered pressure is the gretest of: (1) Pressures cting on inner bottom longitudinl due to bulk crgo in full lod condition, or () Pressures cting on inner bottom longitudinl due to bllst wter in bllst condition, or (3) Pressure cting on inner bottom longitudinl due to bllst wter in bllst hold, if pplicble, in hevy bllst condition. The required net sectionl res of web stiffener re to be clculted independently for the foregoing connections A & B. The finl required net sectionl re of the web stiffener is the greter the clculted res for A & B. A: Web stiffener mid height mens Web stiffener mid length. 497 ttc 6/1.1.5 Question Pressure point for scntling check of corrugtion web 007/10/9 Where is the pressure point in the ttchment to be used for scntling check of corrugtion web? Plese note tht option 1 is inside the gusset/shedder. Therefore, eventully there is no pressure. For the determintion of the net thickness of the web plte ccording to Ch 6, Sec 1, [3..1], the lod point for the pressure is tken t the bottom of corrugtion (e.g., Option 1 in the ttched sketch). The reson is tht the effect of shedder nd gusset pltes is not considered to insure tht the clcultion is conservtive. Y Pge 11 of 31

12 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 516 6/ Question elementry plte pnels 007/7/6 Regrding to Ch 6 Sec 3/1.1.3, "The boundry condition for elementry plte pnels". We normlly consider tht cses 3, 4 nd 7 to 10 of Tble re pplicble where one or two plte edges re supported by solid floors, bottom girders, non-tight/tight bulkhed pltes (bottom/inner bottom plte), side web frmes, side stringers, deck pltes, non-tight/tight bulkhed pltes (side shell) nd Trnsv. webs, deck girders, non-tight/tight bulkhed pltes (deck plte). Plese dvise n exmple of structures for the ppliction of cse 3.4., nd 7 to 10 of tbles for clrity of the requirement in BLC3 nd BLC 4: These BLCs cn be pplied for typicl plte field, where the plte is not continuous t one side. This side my be stiffened with profile without flnge (e.g. Flt br) or not stiffened. Structurl exmples re plte fields locted t mnholes or plte fields of the hopper trnsverse web frme. BLC7: The edge of n elementry plte pnel cn only be treted s clmped edge, when the rottion bout its xis is prohibited. Therefore, this BLC cn be pplied for in web buckling check of stiffeners without flnges which re ttched to very thick plte, e.g. Flt Br 400*0 mm ttched to 50mm thick plte. BLC8 to BLC 10: These BLCs re mostly theoreticl cses included for the ske of completeness of the Tble. There is no cse to be pplicble for n ctul structure / CI Definition of the length of "long superstructur es" 007/8/30 Plese dvise the definition of the length of "long superstructures" specified in Ch6 Sec1,.5.3. Long superstructures re effective superstructures s defined in Ch.9 Sec.4 [1.1.5], i.e. locted within 0.4L midships nd hving length greter or equl thn 0.15L or 1 m. Also Included in Corrigend 5 5 6/.1.4. CI Pressure clcultion positions 007/8/8 The pressure clcultion positions would be clerly defined for verticl stiffeners where spns re corrected ccording to Ch3 Sec Positions for pu nd pl need not to be considered the corrected upper nd lower points of the spn. Or positions for pu nd pl should be lso corrected According to Sec of Tnker CSR, corrected spn need not to be considered. The pressures pu nd pl re to be clculted t the ends of the verticl stiffener - i.e. without considering ny correction of spn - s it is stted in the definition of pu nd pl in Ch 6 Sec [1.4.] nd in ccordnce with the prctice. 55 6/ RCP Primry Support Members 007/10/ Regrding Ch.6, Sec (Primry supporting members - Appliction), the conjunction 'nd' in the pssge quoted below is equivocl hence it is requested to chnge it to 'nd/or' to be such tht trnsverse members to be lso pplied re clery referred to. Quote; 'subjected to lterl pressure nd hull girder norml stresses Unquote; Without the proposed chnge, there would be risk of being red tht the requirement cn be pplied only to longitudinl primry supporting members (PSM) such s bottom girders. The requirement, in prticulr minimum net thickness of webs of primry supporting members (Ch.6, Sec ), should be pplied to trnsverse PSM s well such s trnsverse web in hopper tnk. The requirements of this Section pply to the strength check of pillrs nd primry supporting members,subjected to lterl pressure nd/or hull girder norml stresses for such members contributing to the hull girder longitudinl strength. Also Included In Corrigend 5 Pge 1 of 31

13 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 59 ttc 6/3.4.. & 6/ RCP Buckling requirement for longitudinl nd trnsverse stiffeners 008/6/19 Regrding the buckling requirement for longitudinl nd trnsverse stiffeners (6/3.4.., 6/ ), it is requested tht the Rule sub-prgrphs below re given editoril review in respect of the comments/questions ttched thereto. If these be found justifible, corrigendum would be considered necessry. 1. Nominl lterl lod (Pzy) for trnsverse stiffeners (6/3.4..): In the eqution, sigm_xl should be chnged to sigm_x, since the sigm_x in this cse is not xil stress of the trnsverse stiffeners nd hence the ttched re will not be necessry.. Elstic support provided by the stiffener (cf) for trnsverse stiffeners: (6/3.4..): Cs depends upon degree of fixity t the ends of the stiffener sustining lterl pressure nd is independent of ny elstic support due to in-plne stresses working in the ttched plte. The Cs should therefore be deleted in the relevnt eqution. A1 - It is greed tht in the eqution giving the nominl lterl lod (Pzy) for trnsverse stiffeners (6/3.4..), sigm_xl should be chnged to sigm_x. A The prmeter c_s defines the degree of fixtion for the trnsverse stiffener. In cse of structure s defined in Fig. 1 the trnsverse stiffener will collpse between the longitudinl girder nd not between the longitudinl stiffeners. In this cse c_s reduces the buckling length of the stiffener ccording the Euler buckling cse (prtilly restrined). If it cn be ssumed tht the trnsverse stiffener will collpse between the ordinry longitudinl stiffener c_s =1. Therefore no modifictions of the formuls re necessry. Y 3. Effective width of ttched plting for trnsverse stiffeners (6/ ): The effective width of the ttched plte is considered prt of the stiffener spce nd depends upon working stress long the stiffener. In this connection, kpp_y in the formul should red kpp_y' which is clculted in Ch. 6, Sec. 3, Tble s kpp_x in Buckling Lod Cse 1 with in plce of b. It should be noted tht kpp_y itself in Buckling Lod Cse depends upon the stress working norml in the cse of ppliction to trnsversely stiffened stiffeners. A3 The effective bredth hs to be clculted under the ssumption tht the neighbouring elementry plte field is buckled under lods, cting prllel to the stiffener. Therefore the effective plte bredth hs to be reduced to the effective width. The formule in 4.. re connected to the co-ordinte system, defined in Figure 1. In this figure trnsverse ordinry stiffener (n=1) is locted on the shorter edge of the elementry plte pnel. In cse of n ordinry stiffener, locted norml to the ship's x-xis, but t the longer side of the ttched elementry plte field, this stiffener is LONGITUDINAL stiffener in terms of buckling! Therefore the formul for p_zx hs to be used with the effective with _m nd S_x= trnsverse stress is ship co-ordinte system. But this trnsltion hs not to be done in the rules text. Therefore no modifictions of the formuls re necessry / & 6/..5.4 CI Weight of the Steel Coil 008//7 JBP rules Chpter 6,Section nd Chpter 6,Section..5.4 (steel coil). In this requirement it is stted tht where the number of lod points per element plte pnel n is greter thn 10 nd/or the number of dunnges n3 is greter thn 5, the inner bottom my be considered s loded by uniform distributed lod. The question is how to clculte the bove uniform distributed lod. Is it the weight of the steel coil divided by the dimeter nd length of the steel coil s the uniform lod, or the weight of the steel coil divided by the length of the steel coil only? A similr question ws sked under KC ID #331. The pproved nswer (on 1/01/007) ws "A definition of uniform lods on inner bottom will be included in CSR for bulk crriers. Considering your specific proposls, the interprettion is tht the uniform lod is the weight of the steel coil divided by the dimeter nd length of the steel. We will consider the rule chnge proposl bsed on the output of the Hull Pnel. Pge 13 of 31

14 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment The sequence of the buckling checks follows the rrngement of Chpter 6, Section 3. In cse of the buckling check for typicl ship structure (e.g. longitudinl stiffened bottom) the elementry plte pnel hs to be dimensioned first ccording the plte buckling criteri /3.1 CI The Sequence of Buckling Assessment 008/1/9 Wht is the right sequence of performing the buckling ssessment ccording CH6, Sec3? In the following lterl buckling check of the stiffeners the net moments of inerti is derived including the effective width of the ttched plting. This effective width depends on the thickness of the plte field. If this thickness is not sufficient for plte buckling, the effective width nd lso the moment of inerti of the stiffener is too smll. As result lrger stiffener would be required to pss the lterl buckling check. And this lrger stiffener gives no bonus for the plte buckling check. Therefore it is importnt to mke the plte buckling check before performing the lterl buckling check. 551 Symbol 6.1 Question Counterme sure for pnel buckling 007/10/4 As countermesure for pnel buckling, crling with snipped ends is fitted on slender pnel so s to reduce the spect rtio of the pnel. Cn the reduced spect rtio of the pnel which is clculted by (s/l) be used in determining the thickness of such pnel ccording to Ch 6 Sec 1? Where s nd l re defined in "Symbols" in Ch 6 Sec 1. Yes, the reduced spect rtio of the pnel which is clculted by (s/l) my be used in determining the thickness of such pnel ccording to Ch 6 Sec ttc 6/1..3., 6/1.3..1, & 6/ Question Bilge Plte Thickness 008/1/8 Regrding bilge plte thickness, Q1: Is lwys C6/S1/[.3.] to be pplied regrdless of the spcing (sb) of floors or trnsverse bilge brcket vs chord length (l)? Q: Is C6/S1/[3..1] to be pplied regrdless of the spcing (sb)of floors or trnsverse bilge brcket vs chord length (l)? Q3: Is C6/S1/[3..4] to be pplied regrdless of the spcing (sb)of floors or trnsverse bilge brcket vs chord length (l)? Q4: If C6/S1/[3..4]is to be pplied,is cr to be clculted s follows; () when sb < l: cr=1-0.5sb/r=1.0 ssuming tht R=infinitive, (b) when sb>=l: cr=1-0.5l/r? A1: The requirement of Ch6 Sec 1.3. pplies only to bilge plting which re trnsverslly frmed. A: The requirement of Ch 6 Sec is pplied to bilge plting regrdless of the frming system. A3: The requirement of Ch 6 Sec is pplied to bilge plting regrdless of the frming system. A4: The dditionl stiffness of pnel due to curvture is given by the prmeters rdius nd chord length. If sb>=chord_length, the elementry plte pnel is longitudinl stiffened, hence cr=1-0.5*s/r. If sb<chord length, the elementry plte pnel is trnsverslly stiffened, Cr is tken equl to 1. Y Pge 14 of 31

15 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 563 ttc , 6/ & 6/ Question Modulus of the Lower or upper Brcket 008//7 According to Ch.6 Sec. [3.3.3] nd [3.3.4], section modulus of side frme+brcket is required t the level of lower or upper brcket s shown in Ch.3 Sec.6 Fig.19. According to the Fig.19, it is uncler how to mesure the height of the brcket for the purpose of section modulus clcultion. For the purpose of hlb/tlb rtio the height of the brcket is defined in Ch. 3 Sec. 6 figure, which is lso uncler. We ssume hlb for section modulus nd hlb for hlb/tlb rtio is clculted in the sme wy. Plese confirm. Attched plese find two lterntive pproches for clcultion of hlb. A. hlb is mesured perpendiculr to brcket flnge. B. hlb is mesured perpendiculr to the projection of the lower brcket slope. Plese confirm correct pproch for mesuring brcket height hlb. In Ch 6, Sec 3, [3.3.3] nd [3.3.4], for the purpose of clculting the ctul section modulus of the lower (respectively upper) brcket, the web height is to be mesured t section noted "lower BRACKET" (respectively "UPPER BRACKET") on Fig 19 of Ch 3, Sec 6. In Ch 6, Sec 3, [3.3.3], for the purpose of hlb/tlb rtio the height hlb of the brcket is mesured ccording to the definition in [3.3.3] nd so ccording to Ch 3, Sec 6, Fig. It is corresponding to the Figure B of your ttched document. Y 567 ttc 6/ Question Net thickness offered of the djcent bottom nd side plting 007/10/6 Reference is mde to IACS KC#475. Quote This thickness requirement is referring to the net thickness offered of the djcent bottom nd side plting. Unquote Plese dvise how to define the bilge plting for fwd nd ft prts of the crgo hold region. E.g. - ttched sketch is showing cross section in the fore prt of bulk crrier. - Bottom is strengthened for bow impct - bilge plting is to comply with KC#475. Plese dvise bilge extent. Within 0,4L midship the definition of bilge plte is the sme s defined in Tble of Section 4, CSR for DH oil tnker. Tht is: The re of curved plting between the bottom shell nd side shell. To be tken s follows: From the strt of the curvture t the lower turn of bilge on the bottom to the lesser of, the end of curvture t the upper turn of the bilge on the side shell or 0. D bove the bseline/locl centerline elevtion. Outside of 0.4L midships the bilge plte scntlings nd rrngement re to comply with the requirements of ordinry side or bottom shell plting in the sme region. Considertion is to be given where there is incresed loding in the forwrd region. Y 579 6/ Question Sher force for buckling 008/5/30 Totl sher force for buckling check is to be obtined by following formul Q = Q_SW + C_QW x Q_WV. Then the distribution of totl sher force is discontinuing t midship since the sign of C_QW is to be chnge t midship ccording to the foot note of Tble 3 in Ch4 Sec 4. This discontinuity will cuse scntling chnge between midship, especilly for H1, H, F1 nd F lod cses. Is it correct nd expected? Yes, it is correct but the scntling discontinuity is not expected. We will consider the rule chnge proposl in order to eliminte or minimize the scntling discontinuity, considering the nswer in KC 685. Pge 15 of 31

16 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 580 ttc 6/.3..4 CI The line Supported by girders or welded directly to decks or inner bottoms 007/10/6 In Ch 6, Sec, [3..4], it seems tht in Tble 4 (cse with lower stool), the line Supported by girders or welded directly to decks or inner bottoms should not be mentioned in the tble since this cse is cse without ny lower stool. Plese confirm our interprettion. Furthermore, both Tble 4 nd Tble 5 should not mention the column Supported by girders since it is not pplicble to bulk crriers. We gree with your interprettion: in Tble 4, the only cse to be tken into ccount is the Welded to stool efficiently supported by ship structure one. Also, the supported by girder ends do not correspond to bulk crriers but other type of ships. Consequently, the column Supported by girders should be deleted in Tble 4 nd 5. Corrected tble 4 nd 5 re given in ttched file. Y 581 6/.3..4 Question Spn "I" to be considered for the clcultion of pressures 007/10/5 In Ch 6, Sec, [3..4], wht is the spn "l" to be considered for the clcultion of pressures (p_mid-spn, p_u, P_L)? Is it the spn defined in figure 6 or the spn between upper level of lower stool nd lower level of upper stool? The spn l to be considered for the clcultion of pressures (p_mid-spn, p_u, p_l) is the spn s defined in figure / CI Compressive stress of pillrs 007/10/3 We understnd tht the compressive stress of pillrs mentioned in 6-4/4.1.1 is the stress by the sttic lods nd the dynmic lods. However, there is no cler sttement in CSR how to clculte the lods on pillrs. The cler interprettion on this is to be developed. As n lterntive, we think tht the current Clss Society Rules my be used for determine the pillr scntlings. Plese confirm. Yes, the stress to be checked is the one induced by the sttic nd dynmic lods tht re cting onto the decks bove the considered pillr. These lods re to be clculted ccordingly to chpter / Question The Thickness of the Bilge Strke 008//7 The thickness of the bilge strke is determined ccording CH6, Sec1. The scntling check includes lso buckling check of the longitudinl or trnsverse frmed curved plting. Nevertheless it is required, tht the thickness of the bilge strke is not less thn the greter thickness of the bottom nd the side shell plting. Wht is the reson, tht the thickness of the bilge strke hs to be incresed, if the bilge strke with thickness smller thn the bottom nd the side shell psses ll design checks (Yield, Buckling, FE-Anlyses). The GL-Rules (I-Prt 1, Sec6, 4.1) llows smller thickness, if the sher strength is sufficient nd if the bilge plte pnels psses the buckling check including buckling of curved pnels. In order to hve no lrge discrepncies in thicknesses for welding, it is norml building prctice to provide continuity of thicknesses between bottom, bilge nd side shell. Tht is the reson of the requirement tht the thickness of the bilge strke is not less thn the greter thickness of the bottom nd the side shell. However, provided ll the design criteri hve been fullfilled: - minimum thickness, - yield, - buckling, - FE nlyses, smller thickness of the bilge strke my be ccepted. Pge 16 of 31

17 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 609 ttc 6/1..7.1& 6/..5.4 RCP Steel Coil Loding 008//7 Reference is mde to Ch. 6 Sec. 1 [.7.1] nd Sec. [.5.4] Steel coil loding nd relted KC# 331 nd 546. Ch. 6 Sec. 1 [.7.1] nd Sec. [.5.4] Quote Where the number of lod points per elementry plte pnel n is greter thn 10/or the number of dunnges n3 is greter then 5, the inner bottom my be considered s loded by uniform distributed lod. In such cse, the scntling of the inner bottom ordinry stiffeners is to be obtined ccording to [3..3] Unquote We understnd tht distributed lod is sometimes interpreted s P = WCoil/(lcoil x dcoil) where lcoil nd dcoil is the length nd dimeter of coil respectively. DNV hve investigted the effect of such interprettion with the stiffener scntling s exmple. Our conclusion is tht such interprettion is unsfe nd should be chnged to distributed lod over one elementry plte pnel s described below. Plese find enclosed DNV report nd rule chnge proposl enclosed for your considertion. This question is identicl to KC ID#546, nd the nswer is tht the uniform lod of due to steel coil is the weight of the steel coil divided by the dimeter nd length of the steel. A rule chnge proposl will be considered bsed on the output of the Hull Pnel. Y 1. Lterl buckling ssessment of stiffened pnel including side frme is treted s longitudinlly stiffened pnel which hs stiffener rrnged on the direction of the longer side of the pnel. Plese confirm it. 610 Ch.6, Sec RCP Buckling Assessment of stiffended pnel 008/5/30. In cse tht sher stress on side shell s ttched plte of side frme is lrge, sher stress is the dominnt lod of lterl buckling of side frme. It is not understndble for us. Plese show the technicl bckground in this regrd. Even though the thickness of side shell pltes comply with Ch5 Sec1,. & Ch6 Sec3,.1.3, the side shell plte thickness should be incresed due to the result of lterl buckling ssessment of side frme. It is necessry to reconsider the bove requirements which require increse of scntling of hull girder members due to the result of locl strength check. A1) Confirmed. Comment on ) nd 3) It is obvious, tht for trnsverse members the xil stress component is zero in the formul for the criteri nd the eqution for p_z (nominl lterl lod). The remining stress component is the hull girder bending stress with its zero crossing nd sher. And so sher becomes dominnt. We support to reconsider the requirements for lterl buckling. 3. We request to reconsider the requirement of lterl buckling ssessment for side frme in connection with bove 1. nd. 61 6/3-4. nd 5.1 CI Ultimte Strength in lterl buckling mode of side frmes 008/4/11 Regrding ultimte strength in lterl buckling mode of side frmes of single side bulk crriers in Ch.6, Sec.3-4, our interprettion is tht 'trnsversely rrnged' side frmes should be treted s longitudinl stiffeners in Ch.6, Sec.3-4. nd -5.1 since the ends of side frmes cn be considered s fixed ends tking ccount of the requirements of upper nd lower connections of side frmes s stipulted in Ch.6, Sec Confirmtion is requested s to whether the bove interprettion is correct or not. Yes, side frmes of single side bulk crriers re longitudinl frmes in context of CH6, Sec3. The definition "longitudinl" is given in CH6, Sec3, Symbols nd Fig. 1. This is independent from the fixtion of the ends of the frmes. Pge 17 of 31

18 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 63 ttc 6/A RCP Buckling Pnel ideliztion for d) Generl Tringle 008/4/4 Regrding the buckling pnel ideliztion for d) Generl tringle in Ch 6, Appendix 1, 1.3., it is mentioned tht generl tringle is treted ccording to ) "Qudrilterl pnels" bove. However, in the cse of tringle with ll cute ngles, rectngle with the smllest re cnnot be specified s the three rectngles tht completely surround the generl tringle hve the sme re, see ttched. Just the originl prgrph cnnot result into finl rectngulr pnel with the smllest re represented by the dimensions,, b nd pnel ngle Thet. As such, n lterntive stipultion covering both obtuse tringles nd cute tringles is requested. Neither the DIN18800 nor the GL-buckling rules, which re the bsis for CH6 Sec3 of the CSR-BC, consider tringulr elementry plte pnels s described bove. The ppendix of CH6 describes generl pproches for n engineer to evlute non stndrd geometry. Remeining items re up to engineering judgement. Y 64 ttc Symbol 6.3 & 6/ CI Appliction of buckling requirements 008/5/1 This question reltes to ppliction of buckling requirement (Ch.6, Sec.3) nd SOLAS XII/ (A) According to IACS Unified Interprettion of SOLAS XII/6.5.3 (SC09, June 006), sfety fctor of 1.15 for buckling requirement should be pplied to longitudinl nd trnsverse ordinry stiffeners for the following res: - htchwy coming, - inner bottom, - sloped pnel of topside tnks nd hopper tnks (if ny), - inner side (if ny), - top stool nd bottom stool of trnsverse bulkhed (if ny), - stiffened trsnverse bulkhed (if ny), nd - side shell (if directly bounding the crgo hold). (B) According to Symbols in Ch.6, Sec.3 of CSR-BC Rule, sfety fctor (S) for buckling requirement refers to the sme members s stted in bove (A) except stiffened trnsverse bulkhed, e.g. collision bulkhed nd ft bulked in n ftermost crgo hold. (C) According to Ch.6 Sec () of CSR-BC Rule, the ppliction of the buckling requriement is to 'ordinry stiffeners in hull trnsverse section nlysis'. We think the interprettion of 'hull trnsverse section nlysis' is 'longitudinl members nd hold frmes'. Your interpretion (A) to (C) is correct. We will consider the Rule Chnge proposl or Edditoril correction for clrifiction of the ppliction. Y If the interprettion is correct, loctions to be checked re the sme s stted in bove (A) except stiffened trnsverse bulkhed nd top/bottom stools. Considering the bove sitution, it is considered necessry tht the following elements be inserted: in Sfety fctor (S) in Symbols in Ch.6, Sec.3, 'stiffened trnsverse bulkhed, if ny', in Ch.6, Sec (), 'ordinry stiffeners on stiffened trnsverse bulkhed nd on top nd bottom stools, if ny'. Pge 18 of 31

19 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 69 6/ CI Net thinkness of welded sheerstrke 008/5/9 Regrding the requirement of welded sheerstrke (Ch.6, Sec , The net thickness of welded sheerstrke is to be not less thn the ctul net thickness of the djcent m width side plting, tking into ccount higher strength steel corrections if needed ), it is noted tht there is the relevnt Q&A (KC ID No.1). However, the nswer does not seem cler hence it would be pprecited if the following proposl be considered. The nswer of KC ID No.1 sys, Generlly, when the side shell plting djcent to sheerstrke includes single side prt nd is incresed due to the buckling nd hull girder sher strength, it is lso the cse for the sheerstrke, which is locted bove. Consequently, we see no reson to modify this requirement. This will be the cse when the sheerstrke covers prt of single side skin (SSS) re. However the fct is tht lmost ll sheerstrkes do not cover the prt of single side skin re, i.e. they re locted within top side tnk (TST). We gree to the interprettion tht the net thickness of welded sheerstrke is to be not less thn the net required thickness of the djcent m width side plting, which is clculted ccording to the relevnt requirements in Ch.6, Sec.1 Generlly speking, hull girder sher strength is occsionlly criticl to the scntling of single side skin, while it is not to the scntling of sheerstrke within TST re since the relevnt sher flow clcultion shows tht the sher stress in SSS is considerbly bigger thn tht in TST re. Such being the cse, the requirement should be interpreted s follows: The net thickness of welded sheerstrke is to be not less thn the net required thickness of the djcent m width side plting, which is clculted ccording to the relevnt requirements in Ch.6, Sec.1'. Regrding Ch.6, Sec.1-.7 nd Sec.-.5 bout steel coils, it would be pprecited for KC to reply to the following comments. 1. The requirement for pltes nd ordinry stiffeners on hopper sloping nd inner hull plting (Ch.6, Sec nd Sec.-.5.3) seems to require considerbly severe scntlings s compred to tht in pre-csr BC. In this connection, it is requested tht bckground document be supplied to users. 631 ttc 6/1-.7, 6/-.5 CI Steel coils 008/4/11. It is understood tht the requirements of Ch.6, Sec nd Sec re bsed on the ssumption tht the steel coils re in uniform contct on the hopper sloping or inner hull plting. In ft nd forwrd crgo holds, however, there re some cses where the steel coils do not uniformly touch on them. Attched is the exmple. Hence it is necessry tht procedure of how to del with it in tht cse be provided. A1: A Rule Chnge Proposl with ssocited Technicl Bckground is presently under preprtion. A nd A3: Plese, refer to the nswer of KC ID#546 nd 609. Y 3. Regrding Ch.6, Sec , it is noted tht n nswer of KC ID.331 sys tht definition of uniform lod will be included in CSR BC Rules. In the mentime, it is requested beforehnd to be confirmed tht the 'uniform lod' is not uniform lod over the inner bottom plte but uniform line lods. Pge 19 of 31

20 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 639 6/4.. nd 4..4 Question Net Web thickness requirements 008/7/16 With respect to Net Web Thickness requirements for centre girders, side girders, floors, stringer of double side structure nd trnsverse web in double side structure for ships of less thn 150m in length, it is requested to confirm whether our interprettion below is correct or not. 1. Ch6/4...1, 1.1 ps,ib nd pw,ib re Crgo pressures from Crgo Hold or Bllst pressures from Bllst Hold. These still wter nd wve internl pressures re to be reduced from the corresponding Bllst pressures from Wter Bllst Tnk. 1. ps,bm nd pw,bm re Externl se pressures. These still wter nd wve internl pressures re to be reduced from the corresponding Bllst pressures from Wter Bllst Tnk.. Ch6/4..4.1,.1 ps,ss nd pw,ss re Externl se pressures. These still wter nd wve internl pressures re to be reduced from the corresponding Bllst pressures from Wter Bllst Tnk. 1.1 When the wter bllst tnk of the double bottom is filled up to the tnk top, the sttic nd dynmic pressures due to dry crgoes or hevy bllst re to be reduced from the corresponding bllst pressure of the wter bllst tnk. 1. When the wter bllst tnk of the double bottom is filled up to the top, the externl still wter nd hydrodynmic pressures re to be reduced from the corresponding bllst pressure of the wter bllst tnk..1 When the wter bllst tnk of the double side is filled up to the top, the externl still wter nd hydrodynmic pressures re to be reduced from the corresponding bllst pressure from wter bllst tnk.. When the wter bllst tnk of the double side is filled up to the top, the sttic nd dynmic pressures due to dry crgoes or hevy bllst re to be reduced from the corresponding bllst pressure from wter bllst tnk. It should be noticed tht the sttic nd dynmic pressure combintion of ech lod is not to be negtive (see CH4, Sec5, 1.1.1). ps,lb nd pw,lb re Crgo pressures from Crgo Hold or Bllst pressures from Bllst Hold. These still wter nd wve internl pressures re to be reduced from the corresponding Bllst pressures from Wter Bllst Tnk. In this requirement, Crgo pressure from Crgo Hold is to be ignored / Question Bilge strke or other curved pnels 008/7/ Appliction of the requirement "t>b/100" The formul does not seem pplicble to bilge strke or other curved pnels This is right. This requirement is only pplicble to plnr plte pnels. A rule chnge will be considered / Question thickness for corrugted bulkhed plte 008/10/10 Required thickness for corrugted bulkhed plte Ref. CSR for Bulk Crriers Ch6 Sec.1.1.1, 3..1 nd 3..3 When clculting the required thickness for build-up corrugtion bulkheds in intct condition by 3..1 of Ch.6 Sec.1, should s of the formul be tken greter width of flnge or web ccording to.1.1? We understnd tht the requirements of.1.1 re come from UR S18 nd only pplicble to the requirement of flooding condition. Plese clrify. According to UR S18.4.7, s of the formul for obtining tn is tken nrrower plte width. Cn we use nrrower width for tn in CSR? Plese clrify. 1. Ch 6 Sec 1 [3..1] nd [3..4] s is to be tken equl to the vlue defined in [.1.1]. For built up corrugtion, when the different thickness of flnge nd web re designed, s is to be tken equl to the flnge nd web of corrugtion respectively.. Ch 6 Sec 1 [3..3] 1) s nd p of the 1st formul should be selected respectively for web nd flnge in generl, (e.g., pplied to lso for cold forming corrugted bulkhed), ) s nd p of the nd formul should be selected for nrrower plting, 3) s nd p of the 3rd to 5th formuls should be selected for wider plting. In order to clrify these requirements, we will conisder the RCP. Regrding the nswer of KC 553 The nswer seems to be vgue but not to be incorrect becuse it is obviously tht the elementry plte pnel for built-up corrugted bulkhed is divided into the flnge nd web of corrugtion. Pge 0 of 31

21 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 681 ttc 6/ RCP Gross Thickness nd Net Thickness Scntling 008/4/11 It is proposed tht the prgrph in CSR-BC, Ch.6, Sec., be chnged in prt to eliminte the equivoclity s shown in the seprte ttchment. IACS UR S1 Rev. 4 is bsed on the gross thickness. CSR is bsed on the net thickness scntling. According to Ch 3 Sec 3, the totl corrosion ddition for webs nd flnges of lower brckets of side frme is 5.0mm, nd the totl corrosion ddition of side frme other thn lowe brckets nd upper brckets is 4.5mm. According to the current requirement of 3.3.3, the gross thickness of lower brcket is greter thn.0mm of the thickenss of web of side frme. Therefore, s the current rule of Ch 6 Sec is in line with IACS UR S1, the text is kept s it is Y 68 6/3.4. & 6/3.4.3 Question stiffeners 009/3/3 Are Ch.6, Sec.3, [4.] nd [4.3] pplicble to stiffeners on wtertight trnsverse bulkheds in lower/upper wing tnks nd double side nd on wtertight floors? Ch.6, Sec.3, [4.] nd [4.3] re pplicble to the stiffeners on wtertight trnsverse bulkheds in lower/upper wing tnks nd double side nd on wtertight floors. In cse of hull trnsverse section nlysis, the xil stress for stiffener nd sher stress in ttched plte re not to be considered / & 5/1...1 Question Sher force for buckling ssessment 008/5/30 Ch.6,Sec.3,[.1.3] defines the sher force for buckling ssessment s follows: Q=Q_SW + C_QW x Q_WV. There seems to be no limittion to the signs of Q_SW nd Q_WV for their combintions. On the other hnd Ch.5, Sec.1, [..1] reds: "When they re combined, verticl sher forces Q_SW nd Q_WV in intct condition re to be tken with the sme sign." Which wy should be tken when clculting Q in Ch.6, Sec.3, [.1.3]: ) Q to be clculted only for the combintions where Q_SW nd Q_WV re of sme sign, or b) Q to be clculted for ll combintions where Q_SW nd Q_WV re of either sme sign or opposite signs? Hull girder sher stress check should be performed t the mximum bsolute sher force. Such cse occurs t the combintion of either (1) Q_SW_pos +(C_QW_pos x Q_WV), or () Q_SW_neg +(C_QW_neg x Q_WV), where, C_QW_pos, C_QW_neg : positive nd negtive lod combintion fctors ccording to lod cses s defined in Ch.4, sec.4,tble 3. The sentence in Ch.5, Sec.1, [..1], which is quoted in the question, reflects this interprettion. Therefore we will consolidte the prgrphs referring to sher force combintion into CH5, Sec1 [..1] nd replce CH6, Sec3, [.1.3] with note referring to CH5, Sec ttc 6/.1.4. Question The pressure P 008/7/16 The ttchment contins four pressure distibutions, where the pressure p cn not be derived ccording to the formule in Ch.6 Sec How to clculte the pressure p, used in Ch.6 Sec for exmples (1)The pressure distributions shown in cses (c) to (f) my effectively occur when differentil pressures re to be considered, i.e. only for verticl stiffeners of the outer shell. However, the scntling of such stiffeners is quite lwys governed by the cse "still wter nd wve externl pressures" to be pplied independently of the differentil pressures (see Ch 6, Sec, [1.3.1]). ()In ddition, such distribution of presssure my be pproched by one of the two "stndrd cses" defined in [1.4.]. This gives wrong results, but regrding the comment in (1), it doesn't ffect the scntling. (3)Of course, some definition of "p" for these distributions my be developped, but no effect on scntlings will occur (see comment in (1)bove). Y Pge 1 of 31

22 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 708 ttc 6/ & Figure 6..9 CI Web stiffeners of primry supporting members 008/5/8 Ch.6, Sec., [4.1.3] sys tht this requirement is pplicble to the web stiffeners of primry supporting members in wter bllst tnks when no brcket is fitted. On the other hnd Fig.9 shows, t its left end, the stiffener with integrted brcket t toe to which the subject requirement is pplicble. Wht is ment by "when no brcket is fitted". Plese dvise if the interprettion on pplicbility of the requirement is s per the ttched cses of stiffener. It is obviously tht Cse 1 nd Cse 3 is pplicble to this requirement becuse the brcket is not fitted s shown in the ttched file. For Cse 4 to Cse 6, s the brcket is fitted to the web stiffener nd the vlue h becomes lrge, the stress rnge delt-sigm is smll, then such cses re lwys complied with this requirement. Therefore, lthough Cse 4 to Cse 6 shown in the ttched file is pplicble to the requirement, it is not considered tht the check ccording to this requirement is necessry for such cses. For Cse shown in the ttched file, lthough the brcket is fitted, the smllest bredth of such cse depends on the brcket size nd shpe nd is similr to tht of Cse 3. Therefore, this cse should be pplied to the requirement of Ch 6 Sec [4.1.3] s mentioned in the ttched file. As conclusion, the interprettion specified in the ttched file is correct. In order to clrify this interprettion, the editoril correction will be considered s "Corrigend". Y 717 ttc 6/ CI buckling check 008/9/10 Chpter6_Sec3_[3..4] Does tensile stress need to be considered for buckling check? Regrding the tensile stress, there is still different view point on whether it need to be considered for buckling check or not. There would be solution tht, 1) For check the resultnt buckling utiliztion fctor, combined by sigm_x, sigm_y nd to, the tensile stress need to be considered s the ctul vlues but with negtive sign. ) For check the individul buckling utiliztion fcor, the fctor would be tken s 0. Plese be kindly request to provide clrifiction or confirmtion. 1) Even if the estimted stress is negtive (tensile stress), the buckling check should be crried out ccording to the first formul specified in Ch 6 Sec 3 [3..4] using the ctul vlues. ) No individul buckling checks hve to be performed for tensile stresses. It is clerly stted, "In ddition, ech COMPRESSIVE STRESS... re comply with the following formule." Y 7 6/ Question Pillrs 009/6/ Plese clrify the design lod for pillr scntling clcultion. The design lods cting on the pillr re the sttic nd dynmic lods tht re cting onto the decks bove the pillr under considertion. These lods re to be determined ccording to Chpter 4 considering the relevnt lods on the decks bove /A CI elementry plte pnels 008/9/10 It seems tht the nd & 3rd sentences in Ch 6, ppendix 1, [1..] such s "The effective width... in ccordnce with Ch6, Sec 3 [5]. A constnt stress... djcent elementry plte pnels." could be interpreted s follows: 1) When width of the ttched plte is clculted constnt compressive stress to be ssumed, ccordingly lwys psi=1.0 both for longitudinl nd trnsverse stiffeners. ) Sigm_ in Ch 6, Sec 3 [4..1] nd sigm_x in [4.3.1] for longitudinl stiffener re to be tken s the greter of the following hull girder bending stresses: () stress t hlf length of the stiffener, nd (b) 0.5 of the mximum compressive stress of the djcent elementry plte pnels. Plese dvise if the bove interprettion is correct. 1) Your interprettion is right. Regrdless of the ctul stress distribution of the djecent pltes, psi equl to 1 is ssumed for the clcultion of the effective width ccording to CH6, Sec.3, 5. )sigm_ is the xil stress of the stiffener. In the trnsverse section nlysis this stress is constnt vlue, which is equl to sigm_n for stiffener in ship length direction. sigm_x, sigm_y (in EPP co-ordinte system) nd tu re stresses in the djcent pltes, cting t the position of the stiffener, which cuses dditonl verticl forces on the stiffener. In cse of the trnsverse section nlysis norml stresses in other directions thn in ships longitudinl direction my be set to zero. We will consider the RCP in order to clrify these interprettion. Pge of 31

23 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 764 6/ RCP Corrosion Formul 008/10/7 With reference to the Technicl Bckground, Ch6 Sec, is bsed on NK Rules. The coefficient, 1.1, of the stress formul in Ch6 Sec, is lso shown in NK Rules s correction coefficient for corrosion. However, CSR dopts net scntling pproch nd the scntling considered in the clcultion formul is the net scntling, excluding corrosion dditions. Accordingly, the formul in Ch6 Sec, incorrectly counts corrosion twice. Plese reconsider the wy to consider corrosion in this formul. Considering the originl rules nd the bckground, it is not considered tht the constnt vlue 1.1 used in the formul of CSR bsed on the net scntling pproch is necessry. We will consider the RCP becuse the correction of the formul will give the scntling impct / Question Buckling Assessment 009/3/3 1. It hs come to our notice tht there is n inconsistency between the CSR BC nd IACS UR S17 bout ssessment of the buckling cpbility of the hull structure in flooded condition.. S17.5 requires buckling ssessment for elementry plte pnels nd ordinry stiffeners in hull trnsverse section stting tht Permissible stress nd xil stress buckling strength re to be in ccordnce with UR S However, Prgrph 1.1. of Chpter 6, Section 3 of the CSR BC requires buckling ssessment only for trnsverse verticlly corrugted wtertight bulkheds in flooded condition. 4. Both re IACS documents nd re to be consistent for buckling ssessment for the elementry plte pnels nd ordinry stiffeners. With the dditionl ultimte strength check ccording to CH5, Sec for flooded condition, the requirements of UR S17 nd UR S11 for the buckling ssessment in flooded conditions re fulfilled. 768 ttc 6/3.4.. RCP stiffeners 009/11/3 Plese see the Rule Chnge Proposl in the ttched file. For continuous stiffeners, the bending moment due to the deformtion of stiffener (M0) lwys tkes the sme sign s the bending moment due to the lterl lod (M1), i.e. since Mo cn ct in ny direction. However, for sniped stiffener, the eccentricity of the compressive lod nd the neutrl xis of the plte-stiffener combintion mens tht M0 cn only ct in one direction (i.e. plte in compression). Accordingly, Mo nd M1 should hve the sme sign when the lterl pressure is cting on the plte side, but different signs when the lterl pressure is cting on the stiffener side. Y 771 Ch. 6, Sec. 1 CI crlings 009/5/7 It seems tht the nswer in KC551 is pplicble when fitted with crling effective enough to prevent buckling. Plese show the conditions such s minimum scntlings of the crling which re effective enough to prevent buckling. We will mke rule chnge proposl to estblish minimum scntling requirements for such crlings. Pge 3 of 31

24 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment RCP lterl buckling of longitudinl stiffeners 009/3/3 We hve checked both criteri given in Ch 6, Sec 3 for lterl buckling of longitudinl stiffeners not subjected to lterl pressure: criteri in [4..1] nd [4..] on one side nd criteri in [4..3] on the other side. These criteri were checked in cse of longitudinl stiffeners (flt brs) of non wtertight girders. The conclusions re: (1) - When considering ends of stiffener not sniped: both criteri re equivlent. () - When considering ends of stiffener sniped: both criteri seems equivlent, but it is noticed tht there is no convergence when incresing the scntling of the flt br. The sme problem occurs if bulb or T-br re considered. insted of flt br. Consequently, there re some doubts on the ppliction of the formule for sniped stiffeners nd in prticulr on the defult vlue tken for the ssumed imperfection w0. In cse of longitudinl stiffeners sniped t ends nd locted on non wtertight girders, when pplying the criteri for lterl buckling given in Ch 6, Sec 3 [4..1] nd [4..] on one side nd [4..3] on the other side, it is right tht there is no convergence when incresing the scntling of the stiffener. The requirement Ch 6, Sec 3, [4..3] is only pplicble for non-sniped ordinry stiffeners. We will mke rule chnge proposl to clrify this mtter. Requirement should be re-considered in cse of sniped stiffeners nd technicl bckground should be provided. 80 6/..3. Question Gross Thickness nd Net Thickness Scntling 009/3/3 Regrding the ppliction of Ch6 Sec.3, should hw nd bf of the formule be mesured s gross scntling or net scntling? In Tnker CSR Tble 10..1, it is clerly defined tht the bredth nd depth of stiffeners re bsed on gross scntling. But, in Bulker CSR, there is no cler definition for the clcultion of the net dimensions of ordinry stiffeners given in Ch6 Sec.3. Plese clrify. It is clerly mentioned in the text of [.3] tht ll scntling is the net dimensions / CI FE nd locl requirements 009/3/3 Plese explin the technicl bckground of this requirement. Does this requirement refer to ) only the thickness required by locl requirements? b) both the thickness required by FE nd locl requirements? Typiclly, we hve pipe duct in wy of the keel plting, nd the length of the elementry plte pnels re smller thn outside the pipe duct. The required thickness obtined from the bi-xil FE buckling in wy of the pipe duct my then be smller thn outside the pipe duct. Cn we ccept this smller thickness? This requirement refers to both the thickness required by FE nd locl requirements, s it refers to "ctul" thickness, for mtter of continuity of strength, nd enough strength for docking /4.3 Question Primry Support Members 009/3/10 Reference is mde to Ch. 6 Sec. 4 [3] Additionl requirements for primry supporting members of BC-A nd BC-B ships. The section is referring to net dimensions. Plese dvice how to obtin the net dimensions: ) deduct 0.5tc from gross scntling (In line PSM scntling pplied in FEM) b) deduct tc from gross scntling. (In line with scntling pplied in locl checks) Plese consider specifying this in Ch.3 Sec. The full corrosion ddition is to be considered when pplying Ch.6 Sec.4 [3]. Ch.3 Sec. [.1.1] nd [3.] define the cses where other corrosion vlues re to be used for determining the net dimensions. Pge 4 of 31

25 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 849 Text 6/A Question corrugted BHD 009/6/16 Regrding the buckling ssessment of corrugted bulkhed pltes, the edge stress rtio for their web pltes is defined s 1.0 ccording to Ch.6 App.1 [1.3.4(b)]. This mens tht the stress distribution of such web pltes is ssumed to be uniform. However, due to bending, the ctul stress distributions of these web pltes re not uniform. Therefore, the edge stress rtio,ψ, should be -1.0 in cse where pplying buckling cse1. Plese confirm tht ψ=1.0 is correct or not. The correct vlue of psi is We will consider Rule Chnge Proposl. 85 ttc 6/ & 6/..5 Question Steel Coil Loding 009/9/4 Ch.6 Sec. [4.1.1] defines the required net sectionl re of web stiffeners. 1) Plese confirm the requirement is not pplicble in cse of steel coil loding s specified in Ch.6 Sec. [.5]. ) If 1) is not the cse plese dvise how to clculte the pressure "p" in cse of steel coil loding. 1. The requirement of Ch 6 Sec [4.1.1] is pplicble in cse of steel coil loding becsue the lod due to steel coil is cting on the ordinry stiffener.. Plese find the ttched document. We will conisder the RCP. Y 856 Text 6/1..3 Question bilge plting 009/6/16 Clrifiction of the criteri of the ppliction of ny incresed thickness required for the bilge plting to the djcent bottom nd side shell plting. In cse the stright plte of bottom or side shell shres trnsversely frmed nd curved EPP with the bilge plting, should the required thickness of the bilge plting be pplied to the djcent bottom or side shell plting? Regrding this, in Tnker CSR Corrigend 3 Section 8/..3., the criteri hve been defined clerly for the ppliction of the required thickness of the bilge plting. However, in Bulker CSR Ch 6, Section 1 [.3], there is no cler guideline. Plese clrify. The text of Ch 6 Sec 1 [.3.3] sys: The net thickness of the bilge plting is to be not less thn the ctul net thicknesses of the djcent m width bottom or side plting, whichever is the greter. Therefore, the required thickness of the bilge plting should not be pplied to the djcent bottom or side shell plting 866 ttc Figure RCP web stiffener end connections 009/8/3 In the estimtion of web stiffener connection ends, the definition of the prmeters is to be clrified. When fitting with lrge collr plte supporting stiffener flnge s ttched figure, the prmeters, l_1 nd l_ s defined in the left figure of Fig. 10, re not cler. Plese clrify the bove. In cse tht Ch.6 Sec. [4.1.3] is pplied to the design in question, "scllop width" nd "slot width" in the ttched figure my be treted s the prmeters l1 nd l. Y 878 6/ & 6/1..6. Question effective structure 009/3/10 In corrigend 5, the long superstructure nd short superstructure re modified into effective structure nd non-effective structure in Ch 6, Sec 1, [.5.3] nd [.5.4]. We think Ch 6, Sec 1, [.6.] nd [.6.3] should lso be modified. To be in ccordnce with Ch.6 Sec.1 [.5], terms "long superstructure" hs to be chnge to "effective superstructure" in Ch.6 Sec.1 [.6.], nd "short superstructure" to "non-effective superstructure" in Ch.6 Sec.1 [.6.3] Pge 5 of 31

26 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment Ch 6, Sec, [.5.3] ordinry stiffeners locted on hopper sloping plte or inner hull plting 879 Text 6/..5.3 question hopper sloping tnks 009/6/16 [quote] l' : Distnce, in m, between lod points per elementry plte pnel of inner bottom plte in ship length, sloping plte or inner hull plting, s defined in Ch6, Sec 1, [.7.]. [unquote] Your observtion is correct. The definition of l' is relted to the fctor K3 nd hence vlid for both [.5.] nd [.5.3]. We will consider to move the definition to Symbols or Tble 1 for K3 in corrigend. The title of Subsection [.5.3] concerns hopper sloping pnel nd inner hull plte, excluding inner bottom plte, so the definition of l' should be modified /4...1, 6/4..3.1, 6/ & 6/ Question Scntlings of primry supporting members for ships of less thn 150m in length - definitions 010/3/30 With respect to Ch 6, Sec 4, we hve the following questions: 1.Subsection [..1] nd [.3.1] define BDB s distnce between the toes of hopper tnks t the midship prt, nd define Ps, IB, Pw, IB, Ps, BM, Pw, BM s pressures t the center of the double bottom structure. We think the position to clculte BDB should lso be the center of the double bottom structure s tht of Ps, IB, Pw, IB, Ps, BM, Pw, BM. Plese consider..subsection [.4.1] nd [.5.1] define hds s height of the double side structure between upper end of hopper tnk nd lower end of topside tnk, nd define Ps, SS, Pw, SS, Ps, LB, Pw, LB s pressures t the center of lds which is length of the double side structure between the trnsverse bulkheds under considertion. We think tht the position of hds should lso be t the center of lds s tht of Ps, SS, Pw, SS, Ps, LB, Pw, LB. Plese consider. We gree to your opinion tht B_DB nd h_ds should be clculted t the center of double bottom nd double side of the considered hold respectively. On the other hnd, it is necessry to note tht B'_DB is seprtely defined s the bredth t the position of the floor in Ch6 Sec4,.3.1. In ddition, it is necessry to define h'_ds seprtely s the height t the position of the side trnsverse web in.5.1. Accordingly, the second h_ds in the formul of t1 is chnged to h'_ds in.5.1. We will consider Corrigendum. 83 6/ Question Connection ends of web stiffeners - differences between NK rules & CSR 010/8/6 According to TB, the requirement origintes from NK Rules. However, the requirement in CSR seems conservtive on the following items: 1.The fctor Cship in NK is depending on ship length. In CSR this dependence is deleted. This mens tht we obtin stricter results for L<00m..In NK, Klongi is 1.0 for bulbs. In CSR Klongi is 1.3. This seems conservtive, becuse skew bending moment for bulbs is much less thn for ngle brs. 3.In NK, the pressure is clerly only considering verticl ccelertion. This mens tht the stress induced by the dynmic lod is under the ssumption tht the vessel is under mximum verticl hull girder bending moment. In CSR, there is no specifiction bout which wve the dynmic pressure is bsed on. R nd P wves will give high dynmic pressure in top wing tnk. However, R nd P wve will not give highest verticl hull girder bending moment. CSR should clerly stte the dynmic pressure is under H or F wve. Are the bove differences between NK nd CSR Rules intended? If they re not intended, plese dvise how they should be hndled. 1. Design philosopy underlying CSR is bsed on the "North Atlntic Nvigtion" nd service life of 5 yers. This is different from NK rules. The fctor "Cship" is intentionlly deleted.. We gree with you. This is not intended. We will consider corrigend to clrify this. 3. We hve noted your comment nd we will send it to the Hrmoniztion Tem. Pge 6 of 31

27 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 845 6/ Interpretti on Minimum thickness of elementry plte pnels 010/9/7 Plese specify where the requirement Ch.6 Sec.3 [3.1.1] pplies. Does it only pply to the crgo re, or lso to other res, such s the ft nd fore prts nd mchinery spces? If it pplies lso to the ltter res, we will get significnt increses in plting thickness for some structures, such s wsh bulkheds, pltform decks, etc.. Ch6, Sec3 pplies to the centrl prt s defined in Ch1, Sec1, [.1.3]. It lso pply to mchinery spce s stted in Ch9, Sec3, [1..] with respect to requirements of Ch9, Sec3. However, the minimum thickness requirement bsed on spce in the first sentence of Ch6, Sec3, [3.1.1] ws mde s the first pproch t the initil design stge so tht initil scntling hs certin stiffness. Less scntling my be ccepted on members under little lod. We will consider rule chnge to delete this requirement 883 ttc Text 6/A question buckling ssessment 009/6/16 Ch6 App1, requires tretments on buckling ssessment of side shell pltes which re stiffened verticlly in the following two cses; Cse 1: with pproximtely constnt stresses Cse : with distributed stresses According to the Rules, Cse is pplicble to side shell pnel under distributed stress over the pnel height. In generl, the pnels in wy of side frmes re such stress nd Cse, therefore, is pplied to them. On the contrry, regrding side shell pnels in wy of brckets bove/below side frmes s shown in the ttched sketch, it is considered tht the stress distribution in the pnels is pproximtely constnt. So the tretment of bove Cse 1 is pplied to the buckling ssessment of the pnels. Plese confirm the bove. Your understnding is correct. Y Pge 7 of 31

28 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 896 Text 6/ question primry supporting members 009/6/6 Ch.9 Sec. [4.3] specifies scntling requirements of primry supporting members in ft prt. The minimum thickness of floors is defined in [4.3.1]. However for other PSMs such requirement is not so cler. Plese dvise on the following questions: [A] [4.3.4] refers to Ch.6 Sec.4 requirements for deck PSMs. Do these requirements include Ch.6 Sec.4 [1.5.1]? [B] Plese confirm tht: (1) there is no requirement to minimum thickness for PSMs other thn for floors, i.e., there is no minimum thickness requirment for deck PSMs, side trnsverses, side girders, etc.; or () there is no requirement to minimum thickness for PSMs other thn for floors nd deck PSMs, i.e., there is no minimum thickness requirements for side trnsverses, side girders, etc. A1) Yes, deck PSM hve to fulfill the requirements of Ch.6 Sec.4 considering the lods defined in Ch.9 sec. [.], nd in prticulr the minimum web thickness defined in Ch.6 Sec.4 [1.5.1]. A) No, the requirement for minimum web thickness defined in Ch.9 Sec. [4.3.1] pplies to ll the PSM except those of the deck (see nswer A1 herein). A rule chnge will be issued for clrifying this /1..3. RCP bilge plting thickness 009/8/3 Ch6 Sec1 [.3.] Our understnding is tht the for formul net thickness of bilge plting is bsed on buckling of thin cylindricl shells subjected to externl pressure. Hence, plese specify tht only the externl pressures re to be considered in the formul. Your understnding is correct, nd we will mke n editoril correction to clrify this. 914 ttc Text 6/ RCP Requirement s for side frmes in bllst holds 010/10/0 Ch6 Sec [3.3.1] Side frmes in bllst holds Plese consider the ttched Rule Chnge Proposl regrding requirements to side frmes in bllst holds. As notified in the Technicl Bckground, the requirement Ch.6 Sec. [3.3.1] is bsed on requirement S1.4.1 of the drft text of IACS UR S1 Rev.4 greed t the WP/S meeting of 8-10 April 003. In order to gree with URS1, the m-fctors must be djusted. The new m-fctors will be presented to the Hull Pnel nd to the Hrmoniztion Tem in CI. Once the new m-fctors pproved, they will be modified in CSR BC. Y Pge 8 of 31

29 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 918 6/1.3..3bi s CI Thickness of supporting floor of corrugted bulkhed 010/5/1 With regrd to required net thickness of supporting floor of corrugted bulkhed (Corr.BHD.) with lower stool, plese reply to the following questions. 1.In 6/ bis of RCN No.1-8, the wording of by the first sentence in the second sentence should be deleted becuse there is no relevnt sentence in 6/ It is noted tht the requirement of 6/1.3.. (required plte thickness in flooding) is not pplicble to lower stool side plting in bllst hold becuse it is only pplicble to the plting which constitutes the boundry of comprtments not intended to crry liquids. According to 6/ bis of RCN No.1-8, on the other hnd, required thickness of supporting floor in wy of bllst hold is to be bsed on the required thickness of 6/ Our understnding is tht imginry required thickness of lower stool side plting in bllst hold needs to be clculted in ccordnce with 6/1.3.. in order to obtin required thickness of the supporting floor in wy of bllst hold becuse the concept of 6/ bis comes from UR S18 (Flooding requirement of Corr.T.BHD). But plese confirm. 1: Your observtion is right: The wording of by the first sentence in the second sentence should be deleted becuse there is no relevnt sentence in 6/ : Yes, you re correct. Required thickness of supporting floor in wy of bllst hold is to be bsed on the required thickness of 6/ Imginry required thickness of lower stool side plting in bllst hold needs to be clculted in ccordnce with 6/1.3.. in order to obtin required thickness of the supporting floor in wy of bllst hold. 96 6/ Question Buckling check of corrugted bulkheds 009/9/4 Sher buckling check of bulkhed corrugtion webs When Ch.6, Sec., [3..6] ws moved to Ch.6, Sec., [3.6.1] by RCN1 (1 July 008 Consolidted edition), sher force Q which ws used for the sher buckling check of bulkhed corrugtion webs ws clrified s Sher force t the lower end of corrugtion s defined in originl requirement, UR S18, [3.]. We understnd tht sher buckling check of bulkhed corrugtion webs in Ch 6, Sec.3, [6.1.1] is lso pplicble only to the lower ends of corrugtion. Plese confirm the bove. Your interprettion is correct. We will consider Corrigendum to clrify it. 963 Tble 4.6.1, Text 4/6.3.3., 6/1.3..1, 6/1.3..3, 6/.3..3 & 6/.3..6 Question Design with nonhomogeneou s loding condition 009/1/16 Plese dvise the nswer to the question on the design with the following non-homogeneous loding conditions in the loding mnul: - crgo density is 3.0 nd crgo hold is not loded up to upper deck, - crgo density is lighter thn 1.78 (for instnce 1.7) nd crgo hold is loded up to upper deck. For this design is locl strength check required for intct condition nd flooded condition for the bove loding conditions ccording to Ch.6 Sec.1 [3..1] & [3..3] nd Ch.6 Sec. [3..3] & [3..6] (or [3.6] by RCN1-8)? This question is considered together with KC 851, 859 nd 97 Pge 9 of 31

30 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment 968 6/ Question Flooding requirements of CSR bulker 010/9/ Buckling check is required for longitudinl members in intct condition only. Plese explin how the buckling requirement of URS17 (xil buckling ccording to URS11) is stisfied for t lese BC-A nd BC-B ships. According to KC 460, the buckling check is covered by HULS. Further considertion including the necessity of dditionl buckling check in flooded condition will be requested to the Hrmoniztion Tem. 97 6/ Question Lods on pillrs 010/3/8 There is only the formul bout criticl column buckling stress of pillrs but no cler interprettion on how to clculte the lods on pillrs in CSR BC 6/ According to our experiences, the lods on pillrs re similr between BC nd OT, so we think similr design lod for pillr scntling clcultion s 8/3.9.5 in CSR OT should be provided. We will consider Rule Chnge to include design lod for pillr scntling clcultion similr to CSR OT 974 6/ bis1 Question Net thickness of stool side plting 010/3/8 Our understnding is tht the following sentence in 6/ bis1 of CSR BC is only pplicble to upper stool, plese confirm. [QUOTE] The net thickness of the lower portion of stool side plting is to not be less thn 80% of the upper prt of the bulkhed plting required by [3..3], s pplicble, whichever is the greter, where the sme mteril is used.[unquote] Yes, your understnding is correct. We will consider corrigend to clrify this / bis Question Thickness & mteril requirements for corrugted bulkheds 010/3/8 Rule Ref.: CSR BC 6/ bis [QUOTE] The net thickness nd mteril of the supporting floors nd pipe tunnel bems of corrugted bulkhed, when no stool is fitted, re to be not less thn those of the corrugtion flnges required by [3..3]. When lower stool is fitted, the net thickness of supporting floors re to be not less thn tht of the stool side plting required by the first sentence of [3..]. [UNQUOTE] [3..] nd [3..3] re requirements of flooding condition, which re inconsistent with KC ID10 s followers: QUOTE: KC ID10 In pplying this requirement 6.4., the net thickness nd. mteril properties required for the bulkhed plting, or when stool is fitted, of the stool side plting men tht they re required by the scntling requirement except for the grb loding nd under flooded condition. UNQUOTE Plese clrify bove. We gree tht the reply to KC 10 is inconsistent to the originl requirements of IACS UR S18 which reds; the thickness nd mteril properties of the supporting floors re to be t lest equl to those provided for the corrugtion flnges. Only requirement for GRAB nottion should be excluded. It ws lso the originl intention of KC10. Reference is mde to KC 918 for dditionl informtion Pge 30 of 31

31 IACS Common Structurl Rules Knowledge Centre KCID No. Ref. Type Topic Dte completed Question/CI Answer Attch ment /1 Question Yield strength of nonrectngulr EPP 010/10/0 When ssess the yield strength of non-rectngle EPP, such s EPP of wtertight trnsverse webs of wing tnks, how to mesure the longer or shorter side of EPP? Since this issue involves both CSR BC nd OT, it will be submitted to the hrmoniztion tem / RCP Allowble stress fctors for floors djcent to stools or trnsverse bulkheds 010/5/5 According to UR S0.3.1, llowble sher stress for floors djcent to the stools or trnsverse bulkheds my be tken sigm_f/3^0.5. On the other hnd, in CSR-B of Ch.6, Sec.4, [3.1.], there is no description bout this tretment. It seems tht to pply this tretment to CSR-B is rtionl becuse this requirement hs come from UR0. Plese consider RCP to dd this tretment into CSR-B. In CSR-B of Ch.6, Sec.4, [3.1.], the following tretement will be dded: llowble sher stress for floors djcent to the stools or trnsverse bulkheds my be tken sigm_f/3^0.5 s notified in UR S A corrigend will be issued ttc Text 6/ Interpretti on Mesuremen t of djcent plte width 010/10/0 Keel Plting The following requirements for keel plting cn be found: Ch3, Sec6, Minimum bredth of the keel "b". Ch6, Sec1, Tble Minimum thickness of keel Ch6, Sec1,.4.1 The net thickness of the keel plting is to be not less thn the ctul net thickness of the djcent m width bottom plting. It is not mentioned, if the djcent m width bottom plting hs to be mesured from the edge of the ctul keel strke or from b/. Some current ship designs hve n ctul keel plting width of more thn 3 times the size of b (see ttchment). If Ch6, Sec1,.4.1 is interpeted in wy tht the djcent plte width hs to be mesured from the edge of the ctul keel strke, the width of ffected bottom plting nd the potentil increse of the thickness depends on this rbitrry strke width. We propose to initite Common Interprettion (CI) or to include the outcome of this question in next RCP to clrify tht the djcent plte width hs to be mesured from b/ of CL. Firstly, we do not gree with your interprettion: s for bilge plting, the djcent m re to be considered from the edge of the keel strke, this is in order to void lrge discrepncies in thicknesses for welding. In ddition, considering the djcent m strting from b/ will in most cse include the keel strke which my led to misinterprettions. Consequently the rules re kept s they re nd no interprettion is emitted. Y Pge 31 of 31

32 KC#04 Sniped stiffeners, requirement to buckling cpcity. The CSR Ch. 6 Sec. 3.4 gives requirement to the buckling cpcity of longitudinl nd trnsverse ordinry stiffeners of prtil nd totl plte pnels. According to Ch. 3 Sec. 6 we understnd tht ordinry stiffeners does not ddress sniped buckling stiffeners of primry supporting members. ) Plese explin whether Ch. 6 Sec. 3.4 is pplicble to e.g. the sniped flt brs of longitudinl double bottom girder s shown below. b) Ch. 6 Sec. is giving minimum requirements to ordinry stiffeners. Plese dvice if this requirement is pplicble to sniped buckling stiffeners s shown bove. If bove items ) nd b) re not pplicble for buckling stiffeners, plese comment on the following interprettion. Buckling stiffeners re subject to the following requirements in CSR Bulk: 1. Ch. 3 Sec. 6 Sec h stiffener > l stiffener /1 nd t netstiffener >t minimumgirderweb.. Ch. 6 Sec Net section modulus of web stiffeners of non-wtertight primry supporting members Plese dvise if the bove item 1 is referring to the minimum thickness of the girder web or the lod thickness of the girder web. Plese lso explin wht is ment by the uncler expression; web stiffener mid-height s stted in Ch.6 Sec which reds; their net sectionl re t the web stiffener mid-height is to be not less thn ---.

33 KC#311 Side Shell Supporting re pillr

34 KC#319 Computtion of upper nd lower connection of side frmes of single side bulk crriers The following note is extrcted from the WP/S bckground document for UR S1 revision 4. This version of the UR ws neither officilly relesed, but is the bsis for the requirements of the IACS Common Structurl Rules for bulk crriers. This note is relted to the clcultion of the longitudinls tht support the lower nd upper connecting brckets of the side shell frmes in hopper nd topside tnks. The relevnt requirements re provided in Ch 6, Sec, [3.4] of IACS CSR for bulk crriers. The technicl bckground document hs been modified to dopt the symbols nd nottions of the Common structurl rules for bulk crriers Chpter 6, Section, in order to fcilitte the reding. For the mening of the symbols not defined hereunder, plese refer to the text of the Common Structurl Rules. Checking of section modulus of the longitudinls in Ch 6, Sec [3.4.1] The section modulus of the longitudinls is required to hve sufficient bending strength to support the end fixing moment of the side frme bout the intersection point of the sloping bulkhed nd the side shell. The end fixing moment of the side frme is tht induced by the externl se pressure cting on the side frme (end brckets excluded) nd the deflection nd rottion of the end support due to the loding on the hopper nd the double bottom. The se pressure loding on the end brckets is not included becuse the se pressure loding on this nd on the connecting structure of the hopper nd topside tnk re ssumed to cncel. The end fixing moment, M ef, of the side frme bout the intersection point of the sloping bulkhed nd the side shell in Nm is given s: M ef ( p p ) s l T S W (1) The end fixing moment, M ef, gives rise to line lods on the connected side nd sloping bulkhed stiffeners, q efi, in N/m such tht: M ef qefidi s () i The line lod, q efi, gives rise to plstic bending moments in the connected side nd sloping bulkhed stiffeners, M ci, in Nm given s: qefi M l ci (3) 16 Hence, ssuming n llowble stress equl to yield, the section modulus requirement for connected side or sloping bulkhed longitudinl in cm 3 becomes: ci wi M (4) RY Injecting the expression of M ci from (4) into (3) nd putting q efi in (), we obtin: M ef l l ( ps pw ) l l l wi di T (5) i 16sR Y 16RY The bove expression llows the required section modulus of the connected longitudinls to be determined nd is given under [3.4.1] of Common Structurl Rules for bulk crriers, Chpter 6, Section.

35 Checking of connection re in Ch 6, Sec [3.4.] The connecting force Q efi in N is trnsferred through sher between the brckets nd the longitudinls, with: Qefi sq efi (6) Assuming n llowble sher stress equl to 0.5 R Y, we hve, with Ai in cm the connection re between brcket nd longitudinl: R 10 Q Ybkt efi 10 sq efi (7) Ai Ai Injecting q efi from (3) nd (4) inside (7), we obtin: wi sry lg Ai [ 0.3] (8) l l RYbkt The bove expression provides the required connection re nd is given with the coefficient 0.3 rounded up to 0.4 nd introducing the mteril fctors for brcket nd stiffener to replce the yield strengths rtio, under [3.4.] of Common Structurl rules for bulk crriers, Chpter 6, Section.

36 KC#333 Requirements for web stiffeners ttched primry supporting members Chpter 6 Cpter 3 Cpter 6 Section Section 6 Section 4 Type Wter tight Apply Apply Apply or N. A.? Non tight N. A N. A Apply Rule Title Chpter 6 Scetion. Minimum net thickness of webs of ordinry stiffeners.3 Net Dimensions of ordinry stiffeners Chpter 3 Section 6 5. Stiffening rrngement Chpter 6 Section Minimum net thickness of webs of primry supporting members

37 KC#356 Ch. 6 Sec. [3.3] - Sectionl modulus of min frmes of single side bulk crriers in wy of bllst hold. The requirement for mid-spn sectionl modulus is given in [3.3.1] Quote: The net section modulus w, in cm 3, nd the net sher sectionl re A sh, in cm, of side frmes subjected to lterl pressure re to be not less, in the mid-spn re, thn the vlues obtined from the following formule: ps pw s 3 w 1.15 m 10 (Eq1) m R A sh 1.1 S S Y 5 ps pw s sin B (..) In ddition to the bove provision, the net section modulus w, in cm 3, nd the net sher sectionl re A sh, in cm, of side frmes subjected to lterl pressure in holds intended to crry bllst wter re to be in ccordnce with [3..3]. Unquote. We ssume (p s + p w ) is ll intct pressures s specified in Ch. 6 Sec. [1.3]. Plese confirm. The requirement of [3..3] is Quote The net section modulus w, in cm 3, nd the net sher sectionl re A sh, in cm, of single spn ordinry stiffeners subjected to lterl pressure re to be not less thn the vlues obtined from the following formule: p p s 3 S w 10 (Eq) m R A sh S W Y 5 ps pw s sin Unqoute We ssume this is pplicble for (p s + p w ) from bllst inside the crgo hold only. Our experience is tht the bllst pressure is normlly decisive for these min frmes. For BCA vessel, the sectionl modulus requirement of [3.3.1] cn be written s: ps pw s 3 ps pw s w 3 Eq weq m ms RY ms RY Tht is, the requirement from Eq is x Eq1. The requirement t ends re defined in [3.3.3] for Lower End nd [3.3.4] for Upper End. Requirement for ends re required s x [3.3.1] eqution. Q1: In the text bove Eq1 it is quoted in the mid spn re. Is the sectionl modulus of Eq lso intended to be stisfied in the mid spn re? Q: The requirement of [3.3.3] nd [3.3.4] specifies w END to be two times the section modulus required for midspn re ccording to [3.3.1]. We ssume this is x Eq 1 only nd not x mx(eq1, Eq). Plese confirm.

38 KC#360 Correction: Reference stress, to be the following for LC 1 nd : b' : shorter side of elementry plte pnel Reference stress, to be the following for LC 3 through 10:

39 KC#40 Question / Interprettion Request / Rule Chnge Proposl Form Plese complete this form nd submit it to the IACS Senior Technicl Officer, Mr. Gil Yong Hn, t gilyonghn@ics.org.uk nd zoewright@ics.org.uk or fx it to +44 (0) Pge 1 of Question, Request for Interprettion or Rule Chnge Proposl (RCP): Questions relted to requirements in Ch. 6 Sec.1 nd for flooding: Q1: Ref. Ch. 6 Sec. 1 [3.1.3]/ [3..] nd Sec. [3.1.3]/[3..5] The item Ch. 6 Sec. 1 [3..] is giving Net thickness under flooded condition excluding corrugtion of trnsverse verticlly corrugted bulkheds seprting crgo holds nd Sec. [3..5] Net section modulus nd net sher sectionl re of single spn ordinry stiffeners under flooded conditions(..). The flooding pressure to pf to be used in the formuls is ccording to Ch.6 Sec. 1 [3.1.3] nd Sec. [3.1.3] the flooding pressure pf of Ch. 4 Sec. 6 [3]. Ch. 4 Sec. 6 [3] hve two definitions of pf: [3..1] flooding wter pressure - sttic wter hed including 60% verticl ccelertion. [3.3.6] flooding wter pressure sttic wter hed only As Ch. 4 Sec. 6 [3.3.6] is referring to pressure on corrugtion in empty hold we ssume [3..1] should be used in this context. Plese consider revising Ch. 6 Sec. 1 [3.1.3] nd Sec. [3.1.3] to The lterl pressure in flooded conditions pf is defined in Ch. 4 Sec. 6 [3..1] Q: Ref. Ch. 6 Sec. 1 [3..3] nd Sec. [3..6] The item Ch. 6 Sec. 1 [3..] is giving Net thickness of corrugtions (..) for flooded conditions nd Sec. [3..6] is giving Bending cpcity nd sher cpcity (..) for flooded conditions. Both items refer to the design resultnt pressure nd resultnt force s defined in Ch. 4 Sec. 6 [3.3.7]. Ch. 4 Sec. 6 [3.3.7] is defining the resultnt pressure in combined bulk crgo wter flooding. [3.3.6] is defining the pure wter flooding pressures on corrugtions. This pressure seem to be overlooked in Ch.6. We ssume tht the reference to [3.3.6] is missing in Ch. 6. Plese consider revising the definition of p in Ch. 6 Sec. 1 [3..3] nd Sec. [3..6] to "(..)either [3.3.6] or [3.3.7] whichever greter". Q3: Reference is mde to bove Q1 nd Q. A summry of the flooding requirements in Ch. 6 is enclosed below. Plese confirm/comment our understnding. The following is noted with respect to flooding pressures: Plne boundries covering plne bulkheds/stools of corrugted bulkheds etc. flooding pressure to be wter hed + 60% dynmic verticl ccelertion Corrugtions of trnsverse bulkhed covering corrugtions in between stools only flooding of crgo nd wter combined flooding of wter, sttic hed only. Flooding in Ch.6Sec1 nd Sec

40 Use of requirements for flooding nd corresponding pressure: Ch 6 Ch 6 Ch 6 Ch 6 Sec 1 Sec 1 Sec Sec Type Corrugtions of Ch.4 Sec.6 Ch.4 Sec.6 corrugted bhd N. A [3.3.6]/[3.3.7] N. A [3.3.6]/[3.3.7] Stool plting of corrugte bulkheds Ch.4 Sec.6 Ch.4 Sec.6 [3..1] N. A [3..1] N. A Plne bulkheds Ch.4 Sec.6 Ch.4 Sec.6 [3..1] N. A [3..1] N. A Rules: Tnker Bulker Both Type: Interprettion Question RCP EITHER: OR: Rule Reference Type Section Nme Sub Section 1 Sub Section Sub Section 3 Sub Section 4 Text Figure Ch Tble Symbol (BC only) Generl Rule Reference (e.g. /, or Generl): Received (e.g. 1/0/06): Dy: Month: Yer: Respondent: Client: IACS Member (AB, LR, etc.): DNV Confidentil: Y N Answer or Interprettion: Answer hs lredy been provided to client. Attchments included. Number of ttchments: Flooding in Ch.6Sec1 nd Sec

41 KC#45 Steel coil loding on hopper plte According to Ch. 6 Sec. 1 [.7.3] Hopper sloping plte nd inner hull plting thickness The net thickness of plting of longitudinlly frmed hopper sloping plte nd inner hull is to be not less thn the vlue obtined, in mm, from the following formul: t K g cos 1 Y 1 1 PRY where: sin F Y : Trnsverse ccelertion, in m/s, defined in Ch 4, Sec, [3.] According to Ch. 4 Sec [3.] Y C YG g sin C YS swy C YR roll y A typicl steel coil loding pttern is shown in the figure below. The is denoting the roll ngle nd COG is indicting the centre of grvity of the coils towrds the hopper tnk. Plese see below clcultion of the g cos 1 sin ccelerton term in the eq. [.7.3], Y 1 COG 1 CL

42 The rule formultion for ccelertion ccording to Ch.4 Sec [3.]: The component originting from the roll motion C YR roll y is shown in the figure below. roll, y R z 1 CL The component C g sin YG 0 is given in the following figure: g y =g 0 sin( ) g 0 g z 1 CL

43 The totl component Y C YG g sin C YR roll y, when neglecting the swy component, is illustrted in the figure below. The component norml to the hopper, y sin1, is lso indicted in the drwing. g y =g 0 sin( ) roll,y 1 CL The second term, g g0 cos 1, is shown in the figure below: 1 g g 0 g CL

44 g cos 1 sin is shown below: Totl rule ccelertion Y 1 1 g Totl hopper ccelertion CL Plese note following: 1. Grvity component in the eqution is ccounted for twice.. The roll component is decomposed twice. Tht is, the component norml to ( ) the hopper tnk is decomposed from the trnsverse ccelertion y. 3. The rule formultion is in some cses summing the vectors without sign. This depend on the rtio between the hopper ngle nd the ngle of the vector R. Plese see below sketches. Plese consider below lterntive clcultion. The clcultion is bsed on the two fundmentl ccelertion components grvity,g 0, nd roll ccelertion roll. The coil closest to the hopper is resting on the hopper only. Tht is, the force on the inner bottom is neglected.

45 The ccelertion component norml to ( ) the hopper from roll ccelertion my be described s shown in the figure below: R R 1 R 1 CL The ngle is expressed s: sin y COG R Further more the vector R y COG, R Consequently the ngle my be expressed s: sin y y COG COG R R is the vector from the ship roll centre to the coil COG: The norml ccelertion cn be expressed s: R R sin 180 T R 1 R 180 T R y COG R

46 The grvity component is expressed in the sme wy s the rule formultion- g cos Ref. below figure. g. 1 g g 0 g 1 CL The totl ccelertion is the sum of the contribution from the roll nd the grvity component. R sin 1 g cos 1 g 1 Totl hopper ccelertion CL If we include the swy component nd introduce the lod combintion fctors, the ccelertion cn be written s: C YR R g cos C C Sin( ) sin 1 1 YG YS Swy 1

47 Exmple for stright inner side (no hopper) configurtion 1 = 90. The EDW R1 is choosen s the condition is normlly decisive for inner side/hopper structure. Accelertion term ccording to the rules (EDW R1): Y g cos C YG g sin sin g cos90 sin90 g sin 1 g sin C YS Y swy 1 C roll y g sin roll y g sin roll y YR Y g sin Accelertion term ccording to DNV bove ssumption (EDW R1) C YR R R R cos cos roll y sin roll y g cos C C Sin( ) sin 90 g cos90 g sin y R cos g sin,cos COG g sin g sin 1 g sin 1 YG 180 T R 180 T R YS y Swy COG y COG Plese note tht the roll,y term is negtive in the CSR. Except the x fctor the two terms re identicl. For smll hndy the trem roll,y is bout 0.5 m/s nd gsin = 4.1m/s (typicl =5 deg) CSR ccelertion =7.8m/s DNV interprettion = 3.6m/s R 1 R R R Y y R COG R Q1: Plese note tht the hopper norml ccelertion clculted directly bsed on the fundmentl ccelertions is smller thn the rule ccelertions. Dependent on the term sin 1, the roll ccelertion will work towrds the grvity ccelertion. Plese note tht the ccelertion is sensitive to the definition of COG. The procedure to define COG should be clerly defined in the rules. With reference to IACS KC #380 plese consider bove ccelertion clcultions. Q: DNV hve noted tht the results of eq. [.7.3] give very strict results for the hopper sloping plte. The thickness of the hopper sloping plte is in mny cses in excess of the requirement of the inner bottom. The force on the hopper is lrger thn the force for the inner bottom. This is cused by the Ck fctor which is 4 for tiers stowge. Could you plese give detils regrding the bckground of this term. According to our steel coil experts the stowge is, even though it is shored, quite flexible. Hve there been ttempted ny test to ccount for the mount of force tken by the hopper plting?

48 KC#470 CH6, Sec3, 3..4 Checking criteri Rule Chnge: In ddition ech compressive stress X nd Y nd the sher stress re to comply with the following formule:

49 GL-Answer: In Generl we consider only the rule defined lod cses nd loding conditions for the dimensioning of the structure, which re clled design-lod cses. In cse of buckling checks we hve to ccept, tht in relity lso lod cses exist, they give other lod nd therefore stress combintions s defined in the design-lod-cses. Of course it is gurnteed, tht the design-lod cses cover the cses with respect of the clcultion of the most criticl stress-components. In cse of buckling we hve to consider ll possible stress combintions. This is somewht different nd becuse of tht we require, tht the buckling strength of the plte hs to be high enough to withstnd ech compressive stress cting lone. This mens, tht possible stbilizing effects of pressure stresses re neglected. This cn be illustrted with the following figures. In Figure 1 the interction curve is shown including the Poisson effect. As cn be seen there re stress combintions llowble for which the Sy-component cn be greter, thn in the cse for Sy is cting lone on the plte. Becuse of the problem mentioned bove, the interction curve s the bse for the rule requirements is limited to stress combintions s shown in figure. Plese note tht this figure is given in Appendix 1 of the Buckling-TB-document. Plese refer to Buckling Strength Assessment of Pltes in the IACS Common Structurl rules for Bulk Crriers Smple Applictions, Figure Stresses including Poisson effect (from finite element nlyses) 5,1; 145,7 x < 0,3 * y y [N/mm ] Stresses excluding Poisson effect (for buckling strength ssessment) 199,4; 85,9 y < 0,3 * x x [N/mm ] Figure 1: interction without the requirement tht the plte hs to be stiff enough to withstnd ech compressive stress lone

50 00 Including Poisson Effect Excluding Poisson Effect 150 0,0; 145,4 1 43,6; 145,4 3,0; 145,4 y [N/mm ] 100 x < 0,3 * y 197,1; 86, ,3; 9,5 50 y < 0,3 * x ,3; 0, x [N/mm ] Figure : interction with the requirement tht the plte hs to be stiff enough to withstnd ech compressive stress lone

51 Input Vlues Clculted Vlues Results of Interction Formul (IF) FE-Stresses Buck. red. fctor Mteril Corrected Stresses Fctors Single Terms with converted stresses Proper usge of IF σ x * σ y * τ κ x κ y κ t R eh σ x σ y B e 1 e e 3 1st Term IF nd Term IF IF 1st Term IF nd Term IF IF

52

53

54 KC#483

55 KC#493-1 Internl pressures Loc. of web stiff re Externl pressures

56 KC#493- KC#493 Technicl bckground The combined effect of externl nd internl pressures pplied on ordinry stiffeners depends on the position of the stiffener s specified in CSR BC Chpter 6 Section 1 [1.3]. Elements of the outer shell Two cses re to be considered: 1. the stiffener is locted below the wterline. the comprtment is empty: only the externl still wter nd wve pressures re considered. b. the comprtment is intended to crry liquids: the internl still wter nd wve pressures re to be reduced by the externl still wter nd wve pressures The externl pressures re to be set in ccordnce with the drught tht mtches the loding condition to be ssessed.. the stiffener is locted bove the wterline only the still wter nd wve internl pressures re to be considered. Other elements If the stiffener is ttched to n element tht seprtes two djcent comprtments, then the pressures to be considered re the still wter nd wve lterl pressures of ech comprtment individully loded.

57 KC#497 Where is the pressure point to be used for scntling check of corrugtion web? Plese note tht option 1 is inside the gusset/shedder. Therefore, eventully there is no pressure. Option 3: t the top of shedder Option : t the middle of shedder Option 1: t the bottom of corrugtion

58 Derivtion of the norml stress terms in the formule for p zi CH6, Sec3, 4.. (Dr.-Ing. Arne Schulz-Heimbeck) The formule for the nominl pressures p zx nd p zy contin the influence of norml stresses. 1 y y xl zx c b b t p 1 1 y y xl x zy t A b n c t p with x x xl t b A 1 The xil cting stresses cn be clculted ccording the TB document New Req. of GL for Proof of Buckling Strength (inkl DIN18800).pdf The following derivtion shows the equivlence of the formul for p zx nd the first term of the formul for p zx. A A b t bt b A b t b b t b b t x x x x x xl This derivtion shows in ddition, tht the stress x in the formule for p zx nd p zy is the xil stress, cting in the stiffener. x with * *.3 0 y x where * x nd * y re FE-stresses. In cse of trnsverse stiffener, the stress of the second term with y cn be derived ccordingly. KC#59

59 In the two formule for p zx nd p zy re different ssumptions. Longitudinl stiffeners o re not supported by intermedite trnsverse stiffeners. o ct lwys s secondry members Trnsverse stiffeners o re clssified in two kind of stiffeners ) smll trnsverse stiffener (secondry member), locted between two longitudinls b) trnsverse stiffener with higher rigidity thn the longitudinl stiffener, which is supported by intermedite longitudinl stiffeners nd prtilly constrined t the ends (primry member) The fctor c s chrcterises the support condition t the ends of the trnsverse stiffener in line with the ctegoristion. A secondry (trnsverse stiffener) is simply supported, primry stiffener is prtilly constrined. * x. No intermedite longitudinls hve to In cse ) the stress cting norml to the stiffener is be tken into ccount, so A x is zero nd the term. In this cse is n 1. * xl x In cse b) the intermedite longitudinl stifferners provide n dditionl support for the trnsverse stiffener nd shift the cting norml stress out of the plte plne. It is obvious tht the norml stress hs to be reduced. t tc c x xl x t Ax cx x b x tcx A bt x t Both terms A nd x re much more smller thn 1 nd represent the reduction fctors b for the norml cting stress x with x.

60 KC#557 Bilge Shell Plte Chord length

61 KC#563 b Fig. A Fig. B

62 KC#567

63 KC#580 Tble 4: Vlues of K, in cse d H.5d 0 Upper end support Welded directly to deck Welded to stool efficiently supported by ship structure Tble 5: Vlues of K, in cse d H.5d 0 Section modulus of Upper end support Connected to deck Connected to stool Corrugted bulkhed Stool t bottom

64 KC#609-1 RCP on evenly distributed lod ccording to Ch. 6 Sec. 1 [.7.1] nd Sec. [.5.4] Steel coil loding Lod to be distributed over 1 elementry plte pnel t per sketch below. Uniform distributed lod, when distributed to one elementry plte pnel becomes: P = ( n tier x W coil x l stiff /l coil ) / (l stiff x S stiff ) = ( n tier x W coil ) / (l coil x S stiff ) Lod on one EPP Are of EPP According to our understnding of Ch.6 Sec.1 Tble 3 nd Tble 4, 0% gp between steel coils is included in the clcultions. The sme gp could be included in the formultion for uniform lod giving: P = ( n tier x W coil ) / (1. x l coil x S stiff )

65 KC#609- Steel coil loding ccording to Ch. 6 Sec. 1 [.7.1] nd Sec. [.5.4] Abstrct In the 3 rd JBP October 005 drft Ch. 6 Sec. 1 [.7.4] nd Sec. [.5.4] for steel coil loding, it is proposed to clculte the double bottom s uniformly loded if steel coils re supported by lrge number of dunnges. This pre ssumes tht the dunnges re very stiff nd ble to trnsfer the lod efficiently to the nerest longitudinls. There re no requirements in the rules s to the scntlings or stiffness of dunnges. If dunnge stiffness re disregrded the lod on stiffeners should be chnged to line lod. Comprtive clcultions enclosed herein show the requirement in the Rules to be non conservtive for this cse. Increse of up to 78% is required depending on the longitudinl spcing. Even when clculting the full plstic utilistion of the pnel, disregrding longitudinl stresses, the required sectionl modulus of longitudinls ws 3-10% higher thn the Rule formultion. The clcultions show tht significnt permnent deflection should be expected for both the plting nd the longitudinls of the inner bottom when the design lod condition is pplied to the net scntled structure. Significnt permnent deflection governed by the membrne response is therefore nticipted. Bsed on this ssessment, we re of the opinion tht the rule formultion for inner bottom plting nd longitudinls should be chnged to line lod formultion. It is our considertion tht the introduction of explicit requirements to the scntling nd stiffness of the dunnges is imprcticl.

66 Tble of contents Abstrct... 1 Tble of contents... Introduction... 3 Rule clcultion... 4 DNV lterntive clcultion... 4 Plstic coil clcultion... 5 Clcultion procedure outline... 5 Plstic clcultion... 7 Summry... 8

67 Introduction JBP 3 rd drft, Ch.6 Sec. [.5.4]: Where the number of lod points per elementry plte pnel n is greter thn 10/or the number of dunnges n 3 is greter then 5, the inner bottom my be considered s loded by uniform distributed lod. In such cse, the scntling of the inner bottom ordinry stiffeners is to be obtined ccording to [3..3] DNV interprettion of the text is: If the bottom coil is supported by 6 or more dunnges going trnsverslly, the lod from the coil on the inner bottom cn be simplified to uniform pressure. See below figure. The lod is then trnsferred between the longitudinls by the wooden dunnges. This requires the dunnges to be extremely stiff. It is our opinion tht this ssumption is wrong nd tht the pressure lod should be chnged to line lod on the stiffener. We hve performed smll comprison cse below in order to elborte our understnding of the problem. The following is pre-ssumed. Coil, (or bottom coil), weight is 40t 400kN. Coil length is, including spcing, l c = 1. meters nd dimeter D =1.5 meters. The llowble stress is ssumed to be s R Y =0.9x35/0.78=71N/mm, which is mximum llowble stress for AH3 steel if longitudinl stresses re disregrded. Two stiffener spcings re clculted s 1 =500mm nd s =850mm. The length of stiffeners between floors is ssumed to be l s =.4m. The dynmic ccelertion v is ssumed to be g/. W=40t

68 Rule clcultion The rule clcultion ssumes tht the double bottom is uniformly loded. s=500/850mm l s=.4m Pressure from coil is: P W ( g ) /( Dl ) 40( ) /(1.5 1.) 37kN / m v c Required plte thickness ccording to Sec. 1[.7.4](C =C r =1) P treq, s CCr s 8.68mm t 1 k t req, s C C s r ll P ll 14.75mm t Typicl t k for inner bottom djcent to bllst tnk is 5.4 mm. Required section modulus on stiffener is: 3 Psls 3 wreq, s cm 1 1 w req, s s Psl 49cm 1 3 k DNV lterntive clcultion We ssume tht the lod from the coils re trnsferred s line lod to the nerest longitudinl(s). As the coils dimeter does not mtch the stiffener spcing exctly, there will lwys be one or more coils within the double bottom tht will meet one longitudinl. As this is the worse cse, it should be the dimensioning cse for the longitudinls. F=37kN/m

69 Line lod on the most severe loded longitudinl is: q W ( g ) / l 40( ) /1. 491kN m l v c / Corresponding end moment on stiffener is: qlls M 35kNm 1 The required section modulus is: M w req cm 71 The section modulus is independent of the stiffener spcing. The required section modulus for the DNV clcultion is three times the section modulus required by the Rules when the stiffener spcing is s 1 =500mm. In order to clculte the longitudinls ccording to the Rules, the dunnges hve to be extremely stiff in order to trnsfer the lod efficiently between longitudinls. Plstic coil response clcultion For reference, we hve clculted the ultimte cpcity of the inner bottom subjected to steel coil loding (plstic cpcity). The clcultion procedure used is originlly derived for evlution of ice lods on longitudinlly stiffened pnels. Clcultion procedure outline Lod model It is ssumed tht the dimeter of the coils is lrger thn two primry frme spces, D>s.The steel coil is loded on wooden support, which is soft compred to the steel coil. The coil will deform in to the wood nd spred the lod over smll distnce b of the inner bottom plting, see Figure 1. b Figure 1 Steel coil deforming in to the wooden support As described erlier, the coils will be loded rndomly within the double bottom. The dimeter, D, of the coils do not mtch the primry longitudinl spcing. Consequently, there will lwys be coils meeting longitudinl nd coils t the middle of plte field. The first

70 will be the governing condition for the stiffeners scntlings, wheres the ltter will be the governing condition for the plte scntlings. floor floor b longitudinl b s l Figure Lod model pltes nd longitudinls When the number of dunnges is lrge, the pressure from the steel coils on the wooden support will converge towrds uniform pressure within the bredth b, see Figure. Longitudinls We further ssume plstic response of the plte nd longitudinls. The pressure within b is: ql W ( g v ) P b l b c The required sher re is defined s: P 0.5 b1l As, req 10 y 3 Where b 1 /b is the portion of the lod trnsferred in to the longitudinl nd (b b1)/b is the portion trnsferred through plte bending in to the djcent longitudinls. See Figure 3. l b b 1 Longitudinl Figure 3 Reltionship between b 1 nd b b 1 is given by: b 1 mxk 0 b, b / 3

71 3 10 t y k0 1 ( s b / ) ( s b / ) b P The plstic sectionl modulus of longitudinl is given by: 3 Pb1l Plstc zreq 10 8 y Where plstic is the reltion between the plstic cpcity of the longitudinl t the boundry to the plstic cpcity t mid spn. 1 Plstic k 1 1 wl sher sher A s, req A s, ct without being lrger thn 1. A s,req is the required sher re of longitudinl, wheres A s,ct is the ctul fitted sher re. s =1 will give the mximum required sectionl modulus for the longitudinl. 1 kwl where A fl,ct is the fitted flnge re of the stiffener. Afl, ct 1 A s, ct Pltes Bsed on plstic response of the plte the required thickness is: t req b b 15.8s s s P y Plstic clcultion The plstic clcultion hve been done for the cse with longitudinl spcing, s=850mm. If we ssume b=0.15 m, the required scntling for the bove condition will be: W ( g v ) 40( ) ql 370kN / m bl c The frction of the pressure crried by the stiffener: 3 10 t y k, s ( s b / ) ( s b / ) b P 0 k b, b / 3 mx0.149, m b 1 mx Tht is, the frction of the lod trnsferred to the djcent stiffener is 16.7%. The required sher re: P 0.5 b1l x.4 As, req cm y

72 Required section modulus ssuming sher =1. k wl 1 Afl, 1 ct A s, ct 1 1 (9013.1) z k wl sher 3 Pb1l Plstc cm Plstic req y It should be noted tht this is the required net plstic sectionl modulus for the longitudinl. The elstic sectionl modulus is typiclly 15-0% smller. Hence, the equivlent net elstic section modulus is bout cm 3. Pltes b b P t 15.8s mm req s s y It should be noted tht b=0.15 is ssumed to be slightly conservtive t the middle of the plte spn. If b=0.3m is used the requirement would decrese to 3.86mm. It should be noted tht the globl, xil, stresses re disregrded in bove clcultion. The design condition is plstic, with llowble stress equl to yield. Ftigue is not evluted. If ctul section modulus is smller thn the bove clculted, the longitudinl will deform plsticlly. The shortge will be crried by the plte to the nerest longitudinls by membrne response. (i.e. significnt permnent deformtions) Summry In the 3 rd JBP drft October 005 Ch. 6 Sec. 1 [.7.4] nd Sec. [.5.4] for steel coil loding, it is proposed to clculte the double bottom s uniformly loded if steel coils re supported by lrge number of dunnges. This is pre ssuming tht the dunnges re very stiff nd ble to trnsfer the lod efficiently to the nerest longitudinls. Three clcultions procedures re clculted bove. All with the following coil prticulrs: W=40 tonnes, length 1. meters, dimeter 1.5 meters nd number of dunnges per coil >6. (s=850mm) Dunnge ssumption W req,net [cm 3 ] t req,net [mm] Rule clcultion Very stiff DNV lterntive No stiffness 870 (not clc) Plstic cpcity No stiffness 540* 5.11** disregrding longitudinl stress *Estimted elstic sectionl modulus ** bsed on n ssumed lod bredth b=0.15 meters, see bove clcultion for detils.

73 There is no requirement in the Rules s to the dimensions of dunnges. It is therefore unresonble to ssume uniform pressure ccording to the Rule formultion. If dunnges re ssumed to be without stiffness, the lod should be pplied s line lod on the longitudinls. In our clcultion this corresponds to n increse of longitudinl section modulus of up to 78%, depending on the spcing of the longitudinls. For reference, plstic clcultion ws conducted for the ltter cse. The clcultion ws mde without globl stresses, llowing full plstic utiliztion of the longitudinls, y =300. The clcultion showed required sectionl modulus, compred to the Rule formultion, of +3-10% depending on the w plstic /w elstic rtio of the longitudinls. The clcultions show tht significnt permnent deflection should be expected for both the plting nd the longitudinls of the inner bottom when the design lod condition is pplied to the net scntled structure. Significnt permnent deflection governed by the membrne response is therefore nticipted. Bsed on this ssessment, we re of the opinion tht the rule formultion for inner bottom plting nd longitudinls should be chnged to line lod formultion. It is our considertion tht the introduction of explicit requirements to the scntling nd stiffness of the dunnges is imprcticl.

74 KC#63

75 KC#64 CSR-BC Sfety fctors for stiffener buckling In the third drft of the CSR_BC, the SOLAS sfety fctor S=1.15 for specil members hs been dded. Only the stiffeners of trnsverse bulkheds is missing in the list. BV gives the following explntions by E-mil: For the following, it is bsed on the evolution within MSC discussions. Some extrcts re listed to illustrte the process. Ics submission to MSC 80: Extrct Quote XII/ the structure of crgo res shll be such tht single filure of one stiffening structurl member will not led to immedite consequentil filure of other structurl items potentilly leding to the collpse of the entire stiffened pnel.. As written this regultion could be understood to pply to stiffened plte pnels of the bottom, side shell, deck, inner bottom, longitudinl bulkheds, upper wing tnks nd/or lower wing tnks which re bounded by primry structurl elements such s trnsverse nd longitudinl bulkheds, trnsverse webs, floors or girders (or even more brodly to lso include ech stiffened plte pnel of the trnsverse webs, floors nd girders themselves). IACS considers tht this requirement does not pply to corrugted trnsverse bulkheds, which hve lredy been reinforced ccording to IACS Unified Requirement S18. Unquote The IACS proposl of interprettion, document MSC 80/18/, ws not supported during the MSC 80, nd the tsk of proposing n interprettion ws llocted to n intersessionl working group of the MSC meeting on 1/13 September 005. A new IACS proposl hs been submitted, document ISR ISWG 1/3/. The submission dels with SOLAS regultion XII/6.5.3 s follows: Quote XII/ the structure of crgo res shll be such tht single filure of one stiffening structurl member will not led to immedite consequentil filure of other structurl items potentilly leding to the collpse of the entire stiffened pnel. 5.3 IACS understnds tht the objective of this regultion is to void immedite collpse of the stiffened pnel fter single, loclized mechnicl dmge (such s locl permnent deformtion, crcking or weld filure tht might result from ccidentl dmge within the crgo hold from crgo opertions) of one stiffener of the structure bounding the crgo holds (such s inner bottom, lower hopper tnks, lower hlf of internl longitudinl bulkhed of double side skin bulk crriers or side shell of single hull bulk crriers nd lower stool of trnsverse corrugted bulkheds). Then, for the scope of ppliction described in 3. nd 4. bove, two cses re to be considered: Unquote

76 Extrct of JBP interprettion sent by JF Segretin on 9/1/005 Quote IACS JOINT BULKER PROJECT Technicl Bckgrounds A3(CCS/KR/NK) UNITAS (BV/GL/RINA) - RS Structurl redundncy requirements of SOLAS regultion XII/6.5.1nd in CSR for Bulk Crriers 1 Introduction During the 4th ssembly, MSC Committee of IMO dopted the unified interprettion of SOLAS regultions XII/6.5.1 nd provided here: Regultion XII/ Protection of crgo holds from loding/dischrge equipment 1 The protection of the structure of the crgo holds should be chieved by structurl design fetures such s mndtory ppliction of clssifiction society grb nottion. The protection of htchwys nd comings from grb wire dmge my be chieved by fitting protection brs (e.g. hlf-round br) on the htch side girder (e.g. upper portion of top side tnk pltes), htch-end bems nd the upper portion of htch comings. Regultion XII/ Filure of crgo hold structurl members nd pnels 1 Stiffening structurl member mens stiffener ttched to structurl plting pnel. For the purpose of this interprettion, crgo re includes htchwy comings, topside tnks, side shells, longitudinl bulkheds of double-side skin construction, bilge hopper tnks nd double bottom, but excludes htchwy covers. 3 Structurl members of crgo hold re the htchwy comings, trnsverse bulkheds, pnel pltes of the top-side tnks nd bilge hopper tnks fcing the crgo hold, inner bottom, side shell of single-side skin construction or longitudinl bulkhed of double-side skin construction. Unquote Conclusions So the fctor s=1.15 pplied to ordinry stiffeners which could be fitted on stools of trnsverse Bhds but not in my mind to the corrugtion itself.

77 KC#631 Exmple of n rrngement of steel coil in ftermost crgo hold, showing the steel coils do not uniformly contct the hopper sloping plte.

78 KC#681 - Quote for immedite reference 1. CSR BC Rule, Ch.3 Sec.6/ CSR BC Rule, Ch.6 Sec./ IACS UR S1 (Rev 4) - Unquote Comments: 1. It is considered CSR BC Rule, Ch.3, Sec.6/8.4.1 is equivlent to The thickness of the frme lower brckets is not to be less thn the greter of tw, where tw is the fitted thickness of the side frme web.. in IACS UR S1.. It is lso considered the net thickness of the side frme web plus 1.5mm in CSR BC Rule, Ch.6, Sec./3.3.3 is equivlent to tw,min+ mm in IACS UR S1. (Underlined in red) 3. As such, CSR BC Rule, Ch.6, Sec./3.3.3 is recommended to be chnged to the net minimum thickness defined in Ch.6 Sec./.. of the side frme web plus 1.5mm.