Effects of residual stresses and initial imperfections on earthquake response of steel moment frames

Mathur, Kapil

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https://hdl.handle.net/2142/24180 Copy

Description

Title

Effects of residual stresses and initial imperfections on earthquake response of steel moment frames

Author(s)

Mathur, Kapil

Issue Date

2011-05-25T15:07:33Z

Director of Research (if dissertation) or Advisor (if thesis)

Fahnestock, Larry A.

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Buildings, multi-story
• Steel frames
• Structural stability
• Seismic design
• Dynamic response
• Residual stress
• Imperfections

Abstract

The 2010 AISC Specification establishes the Direct Analysis Method (DM) as the standard stability analysis and design procedure. Although the DM has important benefits over conventional stability design methods, the interface between the DM, the AISC Seismic Provisions and the seismic design requirements in ASCE-7 is not fully established. Since the DM, which was developed for design scenarios that do not contain seismic loading, includes the effects of initial geometric imperfections and inelastic behavior compounded by residual stresses, it is critical to explore the impact of these parameters on the seismic behavior of typical steel buildings before the DM is required for seismic design. To examine these issues, a series of steel special moment-resisting frame models were subjected to monotonic pushover, cyclic pushover and response history analyses. The observed behavior was used to draw comparisons between systems with and without residual stresses and initial imperfections. Cyclic strength degradation at beam-to-column connections was also considered to examine the potential interaction it may have with the other parameters. Whereas the well-known impact of strength degradation on cyclic stability was noted, residual stresses and initial imperfections did not have any appreciable effect on stability behavior for the systems considered. The analyses conducted in this study indicate no clear benefit to using the DM when designing ductile steel systems in high seismic regions and simpler design methods may be equally effective.

Graduation Semester

2011-05

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http://hdl.handle.net/2142/24180

Copyright and License Information

Copyright 2011 Kapil Mathur

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