Advanced Steel Construction

Vol. 2, No. 4, pp. 355-373 (2006)


INELASTIC ANALYSIS OF STEEL FRAMES ACCOUNTING FOR STIFFNESS DEGRADATIONS

 

Lei Xul1,* and Yuxin Liu2

    1 Canadian Cold Formed Steel Research Group

Department of Civil Engineering, University of Waterloo

          Waterloo, Ontario, Canada N2L 3G1

  *(Corresponding author. E-mail:This email address is being protected from spambots. You need JavaScript enabled to view it.)

    2Atomic Energy of Canadian Limited (AECL)

Received: 13 July 2005; Revised: 5May2006; Accepted:6 May2006 

 

DOI:10.18057/IJASC.2006.2.4.3

 

ABSTRACT:

This paper presents a method for nonlinear inelastic analysis of steel frameworks considering both flexural and shearing stiffness degradations in the inelastic range. With the introduction of the so-called stiffness degradation  factors  to  characterize  stiffness  deterioration  associated  with  inelastic  flexural  and  shearing deformations, the stiffness matrix for a beam-column member is formed as in the conventional matrix displacement method of analysis. In deriving the  stiffness coefficients,  geometrical nonlinearity and shear deformation (Timoshenko beam model) are taken into consideration. The material constitutive models account for nonlinear behaviour under single and/or combined stress states. The computational model allows the incremental procedure to reach loading levels at which instability and/or plastic mechanisms occur. Also accounted for in the computational model is the influence of residual stresses on initial-yield and full-yield capacities of members. The proposed nonlinear analysis method is applied for three steel frame examples. Comparisons between the proposed method and other published methods are presented. The results suggest that the proposed method realistically accounts for geometrical nonlinearity and inelastic flexural and shearing behaviour, and is computationally efficient.

 

Keywords:Nonlinear analysis, inelastic behavior, stiffness degradation, shear deformation, steel frameworks

 

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