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Development of Software for Practical Nonlinear Inelastic Analysis S.E. Kim Department of Civil and Environmental Engineering Sejong University Seoul,

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Presentation on theme: "Development of Software for Practical Nonlinear Inelastic Analysis S.E. Kim Department of Civil and Environmental Engineering Sejong University Seoul,"— Presentation transcript:

1 Development of Software for Practical Nonlinear Inelastic Analysis S.E. Kim Department of Civil and Environmental Engineering Sejong University Seoul, Korea Steel Lab., Sejong University, Seoul, Korea

2 Contents Introduction Nonlinear Analysis Nonlinear Inelastic Analysis Verification Modeling and Design Principles Design Example Conclusions Steel Lab

3 Incompatibility of Conventional Design Procedure Introduction Steel Lab., Sejong University, Seoul, Korea Linear Elastic Analysis of System Member Capacity Check by Design Equation Developed on Nonlinear Inelastic Concept

4 Analysis Methods Introduction Steel Lab., Sejong University, Seoul, Korea

5 Design Methods Steel Lab., Sejong University Introduction

6 Benefit of Nonlinear Inelastic Analysis Accounts for geometric and material nonlinearities. Not necessary for separate member capacity check. Overcomes the difficulties due to incompatibility. Steel Lab., Sejong University Introduction

7 Load-Displacement Steel Lab., Sejong University Introduction

8 FEM(ABAQUS, ANSIS, etc.) –Accurate but not practical Plastic – Zone –Accurate but not practical Second – Order Modified Plastic Hinge –Acceptably accurate and practical Introduction Steel Lab., Sejong University, Seoul, Korea Nonlinear Inelastic Analyses

9 2-D Beam-Column Steel Lab., Sejong University Nonlinear Analysis

10 2-D Force - Displacement Stability Functions Steel Lab., Sejong University Nonlinear Analysis

11 Stability Functions Nonlinear Analysis Steel Lab., Sejong University, Seoul, Korea positive in tension

12 3-D Force - Displacement Nonlinear Analysis Steel Lab., Sejong University, Seoul, Korea Stability Function

13 Inelastic Nonlinear Force - Displacement Steel Lab., Sejong University, Seoul, Korea Nonlinear Inelastic Analysis

14 Inelasticity Associated with Residual Stresses Steel Lab., Sejong University, Seoul, Korea for Nonlinear Inelastic Analysis

15 Inelasticity Associated with Flexure Steel Lab., Sejong University, Seoul, Korea for Nonlinear Inelastic Analysis

16 Force-State Parameter( ) AISC-LRFD (Kanchanalai 1977) for Steel Lab., Sejong University, Seoul, Korea Nonlinear Inelastic Analysis

17 Force-State Parameter( ) Orbison (1982) Where, (strong-axis) (weak-axis) Steel Lab., Sejong University, Seoul, Korea Nonlinear Inelastic Analysis

18 Modification of Element Stiffness for the Presence of Plastic Hinge at End A Steel Lab., Sejong University, Seoul, Korea Nonlinear Inelastic Analysis

19 Column Verification Steel Lab., Sejong University, Seoul, Korea

20 Orbisons Six-Story Space Frame Material property Yield Stress 36 ksi Youngs modulus 30,000 ksi Shear modulus 11,500 ksi Load Uniform floor pressure 100 psf Wind load 6 kips (in the Y-direction) Verification Steel Lab., Sejong University, Seoul, Korea

21 Load-Displacement Verification Steel Lab., Sejong University, Seoul, Korea

22 Proposed Modeling Modeling and Design Principles Steel Lab., Sejong University, Seoul, Korea : 10

23 ABAQUS Modeling : 50,000 Modeling and Design Principles Steel Lab., Sejong University, Seoul, Korea

24 Geometric Imperfection Braced Member Unbraced Frame Modeling and Design Principles Steel Lab., Sejong University, Seoul, Korea

25 Design Format AISC-LRFD : member Proposed : system Modeling and Design Principles Steel Lab., Sejong University, Seoul, Korea

26 Twenty-Two Story Frame Design Example Steel Lab., Sejong University, Seoul, Korea Material property Yield Stress 36 ksi Youngs modulus 30,000 ksi Shear modulus 11,500 ksi Load Uniform floor load 115 psf Wind load 7. 8 kips (in the Y-direction)

27 Plan and Elevation of 22-Story Frame Plan Elevation Design Example Steel Lab., Sejong University, Seoul, Korea

28 Member Sizes of 22-Story Frame Beams Columns (1-11 story)Columns (12-22 story) Design Example Steel Lab., Sejong University, Seoul, Korea

29 Load-Displacement Design Example Steel Lab., Sejong University, Seoul, Korea

30 Conclusions A practical inelastic nonlinear analysis of three-dimensional steel frames has been developed Stability functions enable only one or two element per member to capture nonlinear effects The CRC tangent modulus and softening plastic hinge model predict inelastic behavior reasonably well The proposed analysis can be used in lieu of the costly FEM analysis The proposed design method overcomes the difficulties due to incompatible of ASD and LRFD Steel Lab., Sejong University, Seoul, Korea


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