1、 Guide for Buckling and Ultimate Strength Assessment for Offshore Structures GUIDE FOR BUCKLING AND ULTIMATE STRENGTH ASSESSMENT FOR OFFSHORE STRUCTURES APRIL 2004 (Updated February 2014 see next page) American Bureau of Shipping Incorporated by Act of Legislature of the State of New York 1862 Copyr
2、ight 2004 American Bureau of Shipping ABS Plaza 16855 Northchase Drive Houston, TX 77060 USA Updates February 2014 consolidation includes: March 2013 version plus Corrigenda/Editorials March 2013 consolidation includes: February 2012 version plus Corrigenda/Editorials February 2012 consolidation inc
3、ludes: November 2011 version plus Notice No. 2 November 2011 consolidation includes: July 2011 version plus Notice No. 1 July 2011 consolidation includes: July 2010 version plus Corrigenda/Editorials July 2010 consolidation includes: October 2008 version plus Corrigenda/Editorials October 2008 conso
4、lidation includes: June 2007 version plus Corrigenda/Editorials June 2007 consolidation includes: June 2006 Corrigenda/Editorials June 2007 Corrigenda/Editorials and added list of updates ABSGUIDE FOR BUCKLING AND ULTIMATE STRENGTH ASSESSMENT FOR OFFSHORE STRUCTURES .2004 iii Foreword Foreword This
5、Guide for the Buckling and Ultimate Strength Assessment of Offshore Structures is referred to herein as “this Guide”. This Guide provides criteria that can be used in association with specific Rules and Guides issued by ABS for the classification of specific types of Offshore Structures. The specifi
6、c Rules and Guides that this Guide supplements are the latest editions of the following. Rules for Building and Classing Offshore Installations for steel structure only Rules for Building and Classing Mobile Offshore Drilling Units (MODUs) Rules for Building and Classing Single Point Moorings (SPMs)
7、 Rules for Building and Classing Floating Production Installations (FPIs) for non ship-type hulls. In case of conflict between the criteria contained in this Guide and the above-mentioned Rules, the latter will have precedence. These criteria are not to be applied to ship-type FPIs, which are being
8、reviewed to receive a SafeHull-related Classification Notation. (This includes ship-type FPIs receiving the SafeHull-Dynamic Load Approach Classification Notation) In these vessel-related cases, the criteria based on the contents of Part 5C of the ABS Rules for Building and Classing Steel Vessels (S
9、VR) apply. The criteria presented in this Guide may also apply in other situations such as the certification or verification of a structural design for compliance with the Regulations of a Governmental Authority. However, in such a case, the criteria specified by the Governmental Authority should be
10、 used, but they may not produce a design that is equivalent to one obtained from the application of the criteria contained in this Guide. Where the mandated technical criteria of the cognizant Governmental Authority for certification differ from those contained herein, ABS will consider the acceptan
11、ce of such criteria as an alternative to those given herein so that, at the Owner or Operators request, both certification and classification may be granted to the Offshore Structure. ABS welcomes questions on the applicability of the criteria contained herein as they may apply to a specific situati
12、on and project. ABS also appreciates the receipt of comments, suggestions and technical and application questions for the improvement of this Guide. For this purpose, enquiries can be sent electronically to rsdeagle.org. iv ABSGUIDE FOR BUCKLING AND ULTIMATE STRENGTH ASSESSMENT FOR OFFSHORE STRUCTUR
13、ES .2004 Table of Contents GUIDE FOR BUCKLING AND ULTIMATE STRENGTH ASSESSMENT FOR OFFSHORE STRUCTURES CONTENTS SECTION 1 Introduction 1 1 General . 1 3 Scope of this Guide . 1 5 Tolerances and Imperfections . 1 7 Corrosion Wastage . 1 9 Loadings 2 11 Maximum Allowable Strength Utilization Factors 2
14、 SECTION 2 Individual Structural Members 4 1 General . 4 1.1 Geometries and Properties of Structural Members 4 1.3 Load Application 4 1.5 Failure Modes 5 1.7 Cross Section Classification 10 1.9 Adjustment Factor 10 3 Members Subjected to a Single Action . 10 3.1 Axial Tension . 10 3.3 Axial Compress
15、ion . 11 3.5 Bending Moment 13 5 Members Subjected to Combined Loads 15 5.1 Axial Tension and Bending Moment 15 5.3 Axial Compression and Bending Moment 15 7 Tubular Members Subjected to Combined Loads with Hydrostatic Pressure 17 7.1 Axial Tension, Bending Moment and Hydrostatic Pressure . 17 7.3 A
16、xial Compression, Bending Moment and Hydrostatic Pressure 17 9 Local Buckling . 19 9.1 Tubular Members Subjected to Axial Compression . 19 9.3 Tubular Members Subjected to Bending Moment 19 9.5 Tubular Members Subjected to Hydrostatic Pressure 20 9.7 Plate Elements Subjected to Compression and Bendi
17、ng Moment 21 ABSGUIDE FOR BUCKLING AND ULTIMATE STRENGTH ASSESSMENT FOR OFFSHORE STRUCTURES .2004 v TABLE 1 Geometries, Properties and Compact Limits of Structural Members . 6 TABLE 2 Effective Length Factor . 12 TABLE 3 Minimum Buckling Coefficients under Compression and Bending Moment, ks22 FIGURE
18、 1 Load Application on a Tubular Member 4 FIGURE 2 Effective Length Factor . 13 FIGURE 3 Definition of Edge Stresses . 21 SECTION 3 Plates, Stiffened Panels and Corrugated Panels . 23 1 General . 23 1.1 Geometry of Plate, Stiffened Panel and Corrugated Panels 23 1.3 Load Application 25 1.5 Buckling
19、Control Concepts 26 1.7 Adjustment Factor . 27 3 Plate Panels 27 3.1 Buckling State Limit . 27 3.3 Ultimate Strength under Combined In-plane Stresses 30 3.5 Uniform Lateral Pressure . 31 5 Stiffened Panels 31 5.1 Beam-Column Buckling State Limit . 32 5.3 Flexural-Torsional Buckling State Limit . 35
20、5.5 Local Buckling of Web, Flange and Face Plate . 37 5.7 Overall Buckling State Limit . 37 7 Girders and Webs . 39 7.1 Web Plate 39 7.3 Face Plate and Flange 39 7.5 Large Brackets and Sloping Webs 39 7.7 Tripping Brackets 39 7.9 Effects of Cutouts 40 9 Stiffness and Proportions 40 9.1 Stiffness of
21、Stiffeners 40 9.3 Stiffness of Web Stiffeners 41 9.5 Stiffness of Supporting Girders 41 9.7 Proportions of Flanges and Faceplates . 41 9.9 Proportions of Webs of Stiffeners 42 11 Corrugated Panels 42 11.1 Local Plate Panels . 42 11.3 Unit Corrugation 42 11.5 Overall Buckling 44 13 Geometric Properti
22、es 45 13.1 Stiffened Panels 45 13.3 Corrugated Panels 46 FIGURE 1 Typical Stiffened Panel . 24 FIGURE 2 Sectional Dimensions of a Stiffened Panel . 24 FIGURE 3 Typical Corrugated Panel . 25 vi ABSGUIDE FOR BUCKLING AND ULTIMATE STRENGTH ASSESSMENT FOR OFFSHORE STRUCTURES .2004 FIGURE 4 Sectional Dim
23、ensions of a Corrugated Panel . 25 FIGURE 5 Primary Loads and Load Effects on Plate and Stiffened Panel . 26 FIGURE 6 Failure Modes (Levels) of Stiffened Panel 27 FIGURE 7 Unsupported Span of Longitudinal 34 FIGURE 8 Effective Breadth of Plating sw. 35 FIGURE 9 Large Brackets and Sloping Webs 39 FIG
24、URE 10 Tripping Brackets 39 SECTION 4 Cylindrical Shells 47 1 General . 47 1.1 Geometry of Cylindrical Shells . 47 1.3 Load Application 48 1.5 Buckling Control Concepts 48 1.7 Adjustment Factor 49 3 Unstiffened or Ring-stiffened Cylinders 50 3.1 Bay Buckling Limit State 50 3.3 Critical Buckling Stre
25、ss for Axial Compression or Bending Moment 50 3.5 Critical Buckling Stress for External Pressure . 51 3.7 General Buckling . 52 5 Curved Panels 53 5.1 Buckling State Limit . 53 5.3 Critical Buckling Stress for Axial Compression or Bending Moment 53 5.5 Critical Buckling Stress under External Pressur
26、e 54 7 Ring and Stringer-stiffened Shells 55 7.1 Bay Buckling Limit State 55 7.3 Critical Buckling Stress for Axial Compression or Bending Moment 56 7.5 Critical Buckling Stress for External Pressure . 57 7.7 General Buckling . 58 9 Local Buckling Limit State for Ring and Stringer Stiffeners 58 9.1
27、Flexural-Torsional Buckling . 58 9.3 Web Plate Buckling 60 9.5 Faceplate and Flange Buckling . 60 11 Beam-Column Buckling 60 13 Stress Calculations . 61 13.1 Longitudinal Stress 61 13.3 Hoop Stress . 62 15 Stiffness and Proportions 63 15.1 Stiffness of Ring Stiffeners 63 15.3 Stiffness of Stringer S
28、tiffeners . 64 15.5 Proportions of Webs of Stiffeners 64 15.7 Proportions of Flanges and Faceplates . 64 ABSGUIDE FOR BUCKLING AND ULTIMATE STRENGTH ASSESSMENT FOR OFFSHORE STRUCTURES .2004 vii FIGURE 1 Ring and Stringer-stiffened Cylindrical Shell 47 FIGURE 2 Dimensions of Stiffeners . 48 FIGURE 3
29、Typical Buckling Modes of Ring and Stringer Cylindrical Shells 49 SECTION 5 Tubular Joints 65 1 General . 65 1.1 Geometry of Tubular Joints . 65 1.3 Loading Application . 66 1.5 Failure Modes 66 1.7 Classfication of Tubular Joints . 66 1.9 Adjustment Factor . 67 3 Simple Tubular Joints . 67 3.1 Join
30、t Capacity 67 3.3 Joint Cans . 69 3.5 Strength State Limit . 70 5 Other Joints . 70 5.1 Multiplanar Joints 70 5.3 Overlapping Joints . 71 5.5 Grouted Joints . 71 5.7 Ring-Stiffened Joints . 72 5.9 Cast Joints . 72 TABLE 1 Strength Factor, Qu68 FIGURE 1 Geometry of Tubular Joints . 65 FIGURE 2 Exampl
31、es of Tubular Joint Categoriztion 67 FIGURE 3 Examples of Effective Can Length 69 FIGURE 4 Multiplanar Joints 70 FIGURE 5 Grouted Joints . 72 APPENDIX 1 Review of Buckling Analysis by Finite Element Method (FEM) . 73 1 General . 73 3 Engineering Model 73 5 FEM Analysis Model . 74 7 Solution Procedur
32、es 74 9 Verification and Validation 74 This Page Intentionally Left Blank ABSGUIDE FOR BUCKLING AND ULTIMATE STRENGTH ASSESSMENT FOR OFFSHORE STRUCTURES .2004 1 Section 1: Introduction SECTION 1 Introduction 1 General The criteria in this Guide are primarily based on existing methodologies and their
33、 attendant safety factors. These methods and factors are deemed to provide an equivalent level of safety, reflecting what is considered to be appropriate current practice. It is acknowledged that new methods and criteria for design are constantly evolving. For this reason, ABS does not seek to inhib
34、it the use of an alternative technological approach that is demonstrated to produce an acceptable level of safety. 3 Scope of this Guide This Guide provides criteria that should be used on the following structural steel components or assemblages: Individual structural members (i.e., discrete beams a
35、nd columns) see Section 2 Plates, stiffened panels and corrugated panels see Section 3 Stiffened cylindrical shells see Section 4 Tubular joints see Section 5 Additionally, Appendix 1 contains guidance on the review of buckling analysis using the finite element method (FEM) to establish buckling cap
36、acities. 5 Tolerances and Imperfections The buckling and ultimate strength of structural components are highly dependent on the amplitude and shape of the imperfections introduced during manufacture, storage, transportation and installation. Typical imperfections causing strength deterioration are:
37、Initial distortion due to welding and/or other fabrication-related process Misalignments of joined components In general, the effects of imperfections in the form of initial distortions, misalignments and weld-induced residual stresses are implicitly incorporated in the buckling and ultimate strengt
38、h formulations. Because of their effect on strength, it is important that imperfections be monitored and repaired, as necessary, not only during construction, but also in the completed structure to ensure that the structural components satisfy tolerance limits. The tolerances on imperfections to whi
39、ch the strength criteria given in this Guide are considered valid are listed, for example, in IACS Recommendation No. 47 “Shipbuilding and Repair Quality Standard”. Imperfections exceeding such published tolerances are not acceptable unless it is shown using a recognized method that the strength cap
40、acity and utilization factor of the imperfect structural component are within proper target safety levels. 7 Corrosion Wastage Corrosion wastage is not incorporated into the buckling and ultimate strength formulations provided in this Guide. Therefore, a design corrosion margin need not be deducted
41、from the thickness of the structural components. Similarly, when assessing the strength of existing structures, actual as-gauged minimum thickness is to be used instead of the as-built thickness. Section 1 Introduction 2 ABSGUIDE FOR BUCKLING AND ULTIMATE STRENGTH ASSESSMENT FOR OFFSHORE STRUCTURES
42、.2004 9 Loadings Conditions representing all modes of operation of the Offshore Structure are to be considered to establish the most critical loading cases. The ABS Rules and Guides for the classification of various types of Offshore Structures typically define two primary loading conditions. In the
43、 ABS Rules for Building and Classing Mobile Offshore Drilling Units (MODU Rules), they are Static Loadings and Combined Loadings, and in the ABS Rules for Building and Classing Offshore Installations (Offshore Installations Rules), the ABS Rules for Building and Classing Single Point Moorings (SPM R
44、ules) and the ABS Rules for Building and Classing Floating Production Installations (FPI Rules) they are Normal Operation and Severe Storm. The component loads of these loading conditions are discussed below. The determination of the magnitudes of each load component and each load effect (i.e., stre
45、ss, deflection, internal boundary condition, etc.) are to be performed using recognized calculation methods and/or test results and are to be fully documented and referenced. As appropriate, the effects of stress concentrations, secondary stress arising from eccentrically applied loads and member di
46、splacements (i.e., P- effects) and additional shear displacements and shear stress in beam elements are to be suitably accounted for in the analysis. The primary loading conditions to be considered in the MODU Rules are: i) Static Loadings. Stresses due to static loads only, where the static loads i
47、nclude operational gravity loads and the weight of the unit, with the unit afloat or resting on the seabed in calm water. ii) Combined Loadings. Stresses due to combined loadings, where the applicable static loads, as described above, are combined with relevant environmental loadings, including acce
48、leration and heeling forces. The primary loading conditions to be considered in the Offshore Installations Rules, SPM Rules and FPI Rules are: i) Normal Operations. Stresses due to operating environmental loading combined with dead and maximum live loads appropriate to the function and operations of
49、 the structure ii) Severe Storm. Stresses due to design environmental loading combined with dead and live loads appropriate to the function and operations of the structure during design environmental condition The buckling and ultimate strength formulations in this Guide are applicable to static/quasi-static loads, Dynamic (e.g., impulsive) loads, such as may result from impact and fluid sloshing, can induce dynamic buckling, which, in general, is to be dealt with using an appropriate nonlinear analysis. 11 Maximum Allo
