Date of Award

Fall 2001

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Civil and Environmental Engineering

First Advisor

Foley, Christopher M.

Second Advisor

Heinrich, Stephen M.

Third Advisor

Vinnakota, Sriramulu

Abstract

Performance-based seismic design has received significant attention in recent years. ATC (1996) and ATC (1997) outline nonlinear static analysis procedures for the evaluation of structure performance during seismic events. Recently, the yield point spectra technique (Aschheim 2000; Aschheim and Black 2000) has been proposed as a nonlinear static technique for assessing displacement demand placed on building structures during seismic events. Aschheim (2000) and Aschheim and Black (2000) provide an evaluation of the yield point spectra method for fully restrained (FR) structural steel buildings. However, the yield point spectra method contains several assumptions that require verification for PR (semi-rigid) steel frameworks. The objective of this thesis is to perform a detailed evaluation of the yield point spectra technique with respect to application of performance based seismic design of PR steel frames. These frames may be beneficial in seismic zones due to the possibility of isolating damage in specified locations, reducing seismic demand, resulting in more economical structures that still satisfy performance objectives. To achieve this, an understanding of seismic design and analysis will be demonstrated. Two structural steel prototype frames are developed and evaluated. Partially restrained beam-to-column connections and partially restrained base plate connections are used to create combinations of FR/PR frameworks. The yield point spectra technique is utilized to predict seismic demand within many FR and PR frames for various ground motions of varying duration and magnitude. Assumptions implicit in the technique, including the seismic behavior being dominated by first mode response and a relatively stable yield displacement with changes in the lateral strength and stiffness resulting from connections variation, are evaluated. A suite of ground accelerations for various mean recurrence intervals is used for inelastic time history analysis. This analysis of the evaluation frames is used to provide comparison of the demand predicted using the YPS procedure. Particular attention is placed on plastic hinge rotations and connection rotations in the comparison. Recommendations are made regarding the applicability of the yield point spectra method for predicting seismic demand in PR steel frames.

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