1、 Design of Flat Plate StructuresAPI BULLETIN 2VTHIRD EDITION, JUNE 2004Design of Flat Plate StructuresUpstream SegmentAPI BULLETIN 2VTHIRD EDITION, JUNE 2004SPECIAL NOTESAPI publications necessarily address problems of a general nature. With respect to partic-ular circumstances, local, state, and fe
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13、 2004 American Petroleum InstituteFOREWORDThis Bulletin is under jurisdiction of the API Subcommittee on Offshore Structures.This Bulletin provides guidance for the design of steel flat plate structures. Used in con-junction with API RP 2T or other applicable codes and standards, this Bulletin will
14、be help-ful to engineers involved in the design of offshore structures which include flat platestructural components.The buckling formulations and design considerations contained herein are based on thelatest available information. As experience with the use of the Bulletin develops, and addi-tional
15、 research results become available, it is anticipated that the Bulletin will be updatedperiodically to reflect the latest technology.API publications may be used by anyone desiring to do so. Every effort has been made bythe Institute to assure the accuracy and reliability of the data contained in th
16、em; however, theInstitute makes no representation, warranty, or guarantee in connection with this publicationand hereby expressly disclaims any liability or responsibility for loss or damage resultingfrom its use or for the violation of any federal, state, or municipal regulation with which thispubl
17、ication may conflict.Suggested revisions are invited and should be submitted to API, Standards Department,1220 L Street, NW, Washington, DC 20005iiiCONTENTS Page SECTION 1Nomenclature and Glossary 1 1.1 Nomenclature 1 1.2 Glossary.5 SECTION 2General 7 2.1 Scope .7 2.2 References .7 2.3 Range of Vali
18、dity and Limitations 7 2.4 Limit States9 2.5 Verification of Structural Adequacy10 2.6 Structural Component Loads and Load Combinations14 2.7 General Approach to Structural Analysis15 2.8 General Approach to Structural Design.18 SECTION 3Plates .20 3.1 General 20 3.2 Uniaxial Compression and In-plan
19、e Bending23 3.3 Edge Shear.26 3.4 Uniform Lateral Pressure 27 3.5 Biaxial Compression With or Without Edge Shear.29 3.6 Combined In-plane and Lateral Loads 30 SECTION 4Stiffeners33 4.1 General 33 4.2 Column Buckling 35 4.3 Beam-column Buckling.35 4.4 Torsional/Flexural Buckling36 4.5 Plastic Bending
20、40 4.6 Design Considerations.41 SECTION 5Stiffened Panels .42 5.1 General 42 5.2 Uniaxially Stiffened Panels in End Compression44 5.3 Orthogonally Stiffened Panels.45 5.4 Stiffener Proportions .51 5.5 Trpping Brackets .51 5.6 Effective Flange 51 5.7 Stiffener Requirement for In-plane Shear56 5.8 Oth
21、er Design Requirements 56 5.9 Design Considerations.56 SECTION 6Deep Plate Girders.58 6.1 General 58 6.2 Limit States63 6.3 Design Considerations.64 APPENDIX ACOMMENTARY 74 REFERENCES123 APPENDIX BGUIDELINES FOR FINITE ELEMENT ANALYSIS USE.129 Figures 2.7-1 Global, Panel, and Plate Stresses 16 3.1-1
22、 Primary Loads Acting on a Rectangular Plate 22 3.2-1 Long Rectangular Plate.22 3.2-2 Wide Rectangular Plate.22 3.2-3 Buckling Coefficients for Plates in Uniaxial Compression1.25 3.4-1 Coefficients for Computing Plate Deflections 25 3.4-2 Stresses in Plates Under Uniform Lateral Pressure.25 Page 3.5
23、-1 Rectangular Plate Under Biaxial Compression25 4.4-1 Design Lateral Load for Tripping Bracket37 5.1-1 Flat Stiffened Panel.43 5.2-1 Uniaxially Stiffened Panel in End Compression.43 5.3-1 Deflection Coefficient for Orthogonally Stiffened Panels 46 5.3-2 Coefficients for Computing Stresses for Ortho
24、gonally Stiffened Panels 47 5.6-1 Cases for Effective Flange Calculations .52 5.6-2 Effective Breadth Ratio for Case I (Single Web)54 5.6-3 Effective Breadth Ratio for Case II (Double Web).54 5.6-4 Effective Breadth Ratio for Case III (Multiple Webs) 54 5.6-5 Stress Distribution Across Flange.55 5.7
25、-1 Geometry of Stiffened Panels Subjected to In-Plane Shear 55 6.1-1 Typical Deep Plate Girder Structural Arrangement 59 6.1-2 Primary Loads Acting on Plate Girder59 6.1-3 Stress Distribution Across Section Due to Concentrated Load Applied at the Flange Level 59 6.1-4 Transverse Stresses in Webs Due
26、 to Flanges Curved in Elevation .61 6.3-1 Web with Small Openings 65 6.3-2 Web with Large Openings 65 6.3-3 Vertical Stiffener Termination 65 6.3-4 Coefficient for Computing Axial Force Assumed in Preventing Web Buckling 72 6.3-5 Longitudinal Stress in Webs with Transverse Stiffeners 72 C3-1 Rectang
27、ular Plate Under Uniaxial Compression.77 C3-2 Comparison of Inelastic Buckling Formulations for Rectangular Plates Under Uniaxial Compression77 C3-3 Wide Rectangular Plate.84 C3-4 Comparison of Formulations for the Ultimate Strength of Wide Plates with a/b = 3 .84 C3-5 Comparison of Formulations for
28、 the Inelastic Buckling of Rectangular Plates Under Edge Shear .89 C3-6 Model for the Ultimate Strength of Rectangular Plates in Shear 89 C3-7 Comparison of Formulations for the Ultimate Strength of Rectangular Plates in Shear.90 C3-8 Comparison of Formulations for the Ultimate Strength of Rectangul
29、ar Plates Under Lateral Pressure91 C3-9 Rectangular Plate Under Biaxial Compression.91 C3-10 Combined In-Plane and Lateral Loads (b/t = 40)93 C3-11 Combined In-Plane and Lateral Loads (b/t = 20)94 C6-1 Comparison of Minimum Longitudinal Stiffener Stiffness Requirements120 B-1 Panel Weak Axis Bending
30、 Stress Evaluation at Center of Panel 135 B-2 Panel Weak Axis Bending Stress Evaluation at Center of Longitudinal Edge .136 B-3 Design Guideline Plate and Stiffened Panel Applied Stress Locations.137 Tables 4.4-1 Properties of Thin-Walled Open Cross Sections.37 B-1 Minimum FEA Requirements for Stiff
31、ened Plate Structure .138 B-2 FEA Design Guideline for Applied Stresses.139 Section 1-Nomenclature and Glossary 1.1 Nomenclature Note: The terms not defined here are uniquely defined in the sections in which they are used. 1.1.1 Material Properties E = modulus of elasticity, ksi. G = shear modulus,
32、ksi. v = Poissons ratio. Fy= minimum specified yield stress of material, ksi. y= 3/yF yield stress in shear, ksi. Fp= proportional limit stress in compression, ksi. pr= Fp/ Fystress ratio defining the beginning of nonlinear effects in compression. 1.1.2 Plate Geometry and Related Parameters a = plat
33、e length or larger dimension, in. b = plate width or shorter dimension, in. D = Et3/12 (1 - v2) plate flexural rigidity, kips-in. t = plate thickness, in. = a/b 1 aspect ratio = EFtby/)/( slenderness ratio 1.1.3 Stiffener Geometry and Related Parameters A = cross sectional area, in.2 Aw= web area, i
34、n.2 b = spacing between stiffeners, in. be= effective width of attached plating, in. bf= flange total width, in. Cw= warping constant (see formulas in Table 4.4-1), in.6 d = web depth, in. I = minimum moment of inertia, in.4Ic= polar moment of inertia about centroid, in.4Is = polar moment of inertia
35、 about shear center, in.4 Il= moment of inertia of symmetric I-section in the plane of minimum stiffness, in.4 I2= moment of inertia of symmetric I-section in the plane of maximum stiffness, in.4 J = torsion constant (see formulas in Table 4.4-1), in.4K = effective length ratio, normally taken as un
36、ity. L = unsupported length, in. Lb= bracing distance, in. Bulletin 2V-Design of Flat Plate Structures 1 Ly= length at which there is a transition between elastic and plastic limit state moments for lateral buckling, in. r = A / I radius of gyration, in. S = section modulus for bending of symmetric
37、I-section in the plane of maximum stiffness, in.3 s = spacing between tripping brackets, in. t = attached plate thickness, in. tf= flange thickness, in. tw= web thickness, in. = EFrKLy/)/( stiffener slenderness ratio. 1.1.4 Stiffened Panel Geometry and Related Parameters A = entire panel length, in.
38、 A2= area of flange in stiffened plating (zero in the case of flat bar stiffeners), in.2As= stiffener area, in.2 B = entire stiffened panel width in the case of a stiffened panel (see Figure 5.1-1), or distance between webs for effective flange breadth calculations (see Figure 5.2-1), in. 2b = plate
39、 breadth, or distance between webs, in. (See Figure 5.6-1) bef= effective breadth, in. d = spacing between stiffeners = 2b, in. h = one half web depth, in. Is= moment of inertia of one stiffener about an axis parallel to the plate surface at the base of the stiffener, in.4L = length, in. cL = distan
40、ce between points of zero bending moment, in. n = number of sub-panels (individual plates). t = plate thickness, in. tf= flange thickness, in. tw= web thickness, in. = aspect ratio of whole panel = )/()1(1232dtIvs = As/(Bt) = )/()1(12)/(22kEvFtBy , modified slenderness ratio for uniaxially stiffened
41、 panels, where k is the buckling coefficient. Ix, Iy= moment of inertia of the stiffeners with effective plating extending in the x- or y-direction, respectively, in.4 Ipx, Ipy = moment of inertia of the effective plating alone associated with stiffeners extending in the x- or y-direction, respectiv
42、ely, about the neutral axis of the entire section, in.4 sx, sy= spacing of the stiffeners extending in the y- or x-direction, respectively, in. Bulletin 2V-Design of Flat Plate Structures 2 tx, ty= equivalent thickness of the plate and the stiffeners (diffused) extending in the x-direction or y-dire
43、ction, respectively, in. Mx, My = moment per unit length that produces a stress fxor fy, respectively, kips ra, rb= bending lever arm associated with fxor fy, respectively, i.e., distance from the neutral axis of the stiffener with the effective breadth of plate to the outer fiber of the flange (for
44、 the flange stress) or of the plate (for the plate field stress), in. 1.1.5 Deep Plate Girder Geometry and Related Parameters Af= flange cross-sectional area, in.2 a = spacing between transverse web stiffeners, in. ah= web opening height, in. Bf= width of unstiffened flange in a beam with only one w
45、eb, or half the distance between successive longitudinal stiffeners or webs, together with any adjacent outstand, in. (See Fig. 6.1-4.) b = spacing between longitudinal web stiffeners, in. (See Fig. 6.3-1.) be= effective plate flange width attached to web stiffeners, in. bh= web opening length, in.
46、(See Fig. 6.3-1) ds= spacing between web longitudinal stiffeners, in. dw= web depth, in. Rf = flange radius of curvature, in. sh= clear distance along the longitudinal direction between web openings, in. tf= flange thickness, in. tw= web thickness, in. = slope of web to horizontal. 1.1.6 Stresses 1.
47、1.6.1 Normal Stresses: f = normal stress, ksi. fx, fy= normal stress directed along the x and y axis, ksi. fxy= in-plane shear stress, ksi fse= elastic serviceability limit state stress, ksi. fsp= plastic serviceability limit state stress, ksi. fu= ultimate limit state stress, ksi. fxse= normal stre
48、ss fsewhen the plate is compressed in the x direction alone, ksi fyse= normal stress fsewhen the plate is compressed in the y direction alone, ksi. fxyse= edge shear stress fsewhen the plate is loaded in pure shear, ksi. fxysp= edge shear stress fspwhen the plate is loaded in pure shear, ksi. fxyu=
49、edge shear stress fuwhen the plate is loaded in pure shear, ksi. fxl= limit state normal stress in the x direction when the plate is compressed in the x direction, ksi. Bulletin 2V-Design of Flat Plate Structures 3 fyl= limit state normal stress in the y direction when the plate is compressed in the y direction, ksi. fxyl= limit state shear stress when the plate is loaded in pure shear, ksi. 1.1.6.2 Sh
