1、Designation: F2991 13Standard Guide forDoubler Plate Repairs for Non-Classed Ship Structures1This standard is issued under the fixed designation F2991; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers information for designing permanentsteel doublers for surface ships that are not classed with anyclassification society
3、, and not load line certified. It is notintended to supersede any classification or statutory require-ments.1.2 This guide provides owners, operators, shipyards, anddesigners with information for designing and using doublerplates so that the damaged structure regains its original localstrength.1.3 W
4、hen the steel is to be welded a welding proceduresuitable for the grade of steel and intended use or service is tobe utilized. See Appendix X3 of Specification A6/A6M forinformation on weldability.1.4 The values stated in metric units (SI) are to be regardedas the standard. The values given in paren
5、theses (inch/pound)are provided for information only.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility o
6、f regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A6/A6M Specification for General Requirements for RolledStructural Steel Bars, Plates, Shapes, and Sheet PilingA36/A36M Specification for Carbon Structural SteelA131/A131M Specification for Structural Steel for Ships2.2
7、 Other Documents:AWS D 1.1 Structural Welding Code3NVIC 7-68 Navigation and Vessel Inspection Circulars4SSC-443 Design Guidelines for Doubler Plate Repairs ofShip Structures53. Terminology3.1 Definitions:Definitions of Symbols Specific to ThisStandard:3.1.1 combustible liquidliquid having flashpoint
8、 above80F (Grade D and E liquid).3.1.2 corrosiona state of deterioration in metals caused byoxidation or chemical reaction.3.1.3 doubler platea plate lap welded to damaged part ofa structure to regain its original local strength.3.1.4 flammable liquidliquid having flashpoint at or below80F (Grade A,
9、 B and C liquid)3.1.5 fracturefracture occurs when metal experiencesstresses that exceed ultimate strength.3.1.6 tank vesselsall vessels (tank barges and tankships)carrying combustible or flammable liquid cargo in bulk.4. Introduction4.1 The intent of this guide is to design and weld a doublerplate
10、to the damaged portion of the structure so that thedamaged structure regains its original local strength. Thisguide should be used to design a specific doubler plate for aspecific damage.4.2 These guidelines are based on the study performed onbehalf of Ship Structure Committee (SSC) and are publishe
11、d inthe report SSC-443.1This test method is under the jurisdiction of ASTM Committee F25 on Shipsand Marine Technology and is the direct responsibility of Subcommittee F25.01 onStructures.Current edition approved Feb. 1, 2013. Published February 2013. DOI: 10.1520/F2991-13.2For referenced ASTM stand
12、ards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Welding Society (AWS), 550 NW LeJeune Rd.,Miami, FL 33126, htt
13、p:/www.aws.org.4Available from the United States Coast Guard (USCG) website: http:/www.uscg.mil/hq/cg5/nvic/5Available from the Ship Structure Committee website: http:/www.shipstructure.org/Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United Sta
14、tes14.3 This guide can be used to repair damages caused bycorrosion and pitting and is applicable to all surface type steelvessels. This guide does not apply to submarines and pressurevessels.4.4 This guide does not cover straps welded to deck and sideshell to increase the section modulus of the ves
15、sel.4.5 The size of doubler plate depends on the size, thicknessand location of the damaged structure. The design of thedoubler plate shall be in accordance with Fig. 1(a and b) andTable 1, and include:4.5.1 Thickness4.5.2 Dimension4.5.3 Corner radius4.5.4 Overlap4.5.5 Welding type (slot vs. fillet
16、weld)5. Applicability of Doubler Plates5.1 Doublers can be used if:5.1.1 Reduction in plate thickness is less than 25 % of theoriginal thickness.5.1.2 Reduction in web thickness of girders/frame/stiffenersis less than 20 % of the original thickness.5.1.3 Reduction in flange thickness of girders/fram
17、e/stiffeners is less than 20 % of the original thickness.5.1.4 Indentation is less than twice the plate thickness5.2 Doubler plates cannot be used in the following loca-tions:5.2.1 Tanks carrying combustible and flammable liquids.5.2.2 There are many scattered patches clustered together,or a large a
18、rea, unless the sum of the area(s) is less than 15 %of the total deck or bottom area and not situated within 0.4Ladmidship.5.3 Hull Girder Strength:5.3.1 If many patches cluster together or a large area of deckor bottom admidship is involved, the hull girder longitudinalstress shall not increase by
19、15 % or more.6. Materials and Manufacture6.1 Doubler plate shall be of material with physical proper-ties equal to or better than that of the parent plate.6.2 Steel shall conform to the requirements of SpecificationA36/A36M, A131/A131M, or equivalent.6.3 Welding shall conform to AWS D 1.1 or equival
20、ent.6.4 Proper design and controlled welding procedures shallbe followed.6.5 Welders are to be qualified in accordance with therecognized standards of an IACS Classification Society or to arecognized national or international standard.7. Dimensions7.1 The dimensions shall be in accordance with Table
21、 1.7.2 Dimensions are given in millimetres (mm).8. Workmanship, Finish, and Appearance8.1 Doubler plate shall be free sharp edges, burrs, carbur-ized flame cut material, and weld spatters.8.2 FinishDoubler plate shall be sand or shot blasted toremove rust and scale and given a complete coat of prime
22、r/topcoat based on the environment and compatibility withcoatings on the existing structure.8.3 Welds are to be inspected by a certified NDT Level IIinspector.9. Inspection9.1 All doubler plates shall be visually inspected forworkmanship, finish, and appearance as defined in Section 8.10. Keywords10
23、.1 crack; damage; doubler; failure; fracture; structures;weldsFIG. 1 a Doubler Plate GeometryF2991 13211. NomenclatureBL= length of stiffened panelBW= width of stiffened panelBt= thickness of stiffened panelCL= length of damaged/corroded portionCW= width of damaged/corroded portionCt= remaining thic
24、kness of stiffened plate after damage/corrosionDL= length of doubler plateDW= width of doubler plateDt= thickness of doubler plateDR= fillet radius of doubler plates = stiffener spacing of stiffened plateSL= height of stiffener webSW= width of stiffener flangeSt= thickness of stiffener web and flang
25、eSo= size of overlap 0.5*(DLCL) or 0.5*(DWCW)tw= weld leg lengthASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any suc
26、h patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invite
27、d either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a
28、fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this
29、standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).FIG.
30、 1 b Doubler Plate Geometry (continued)TABLE 1 Recommended Guidelines for Doubler Plate RepairsItem GuidelinesMinimum Damage Thickness (Ct)Ct$ 0.75 * BtDoubler Thickness (Dt) $ 0.65 * BtOverlap (So)50# S # 100 mmDoubler Corner Radius (DR)DR=85*(Dt/Bt)(DRminimum = 50 mm)Circular Doubler Minimum 200 mm in diameterMaterial Grade Same as parent plate or compatibleWelding As for new constructionWeld Size (throat thickness) 0.6 * DtF2991 133
