1. Steel Lab., Sejong University, Seoul, Korea
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
세종대학교 Steel Lab

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

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

5. Steel Lab., Sejong University
Introduction
Design Methods
Steel Lab., Sejong University

6. Benefit of Nonlinear Inelastic Analysis
Introduction
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

7. Steel Lab., Sejong University
Introduction
Load-Displacement
Steel Lab., Sejong University

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

30. Steel Lab., Sejong University, Seoul, Korea
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