The Impact of Strength on the Seismic Performance of Frames

Student: Jia Wang
Supervisors: Prof. Robert E. Englekirk


Traditionally, increasing structure strength is regarded as an approach to improve seismic performance by most design codes. However, design experience tells us that it does not always work, which implies the presumed monotonic relationship between strength and seismic performance is problematic.

The aim of this paper is to explore the actual relationship between performance and a structure’s strength. The relationships developed between frame strength and performance parameters are based on an inelastic time history analysis of high-rise, medium-height, and low-rise frames, both steel and concrete, using three representative earthquake records. The inelastic, elastic time history analyses and push-over analyses are carried out using RAM Perform 2D.

It is shown that there exists an optimal strength range in the performance vs. strength relationship. Within this range, the structure performs best under earthquakes and the cost is most effective. The optimal strength range is not uniformly quantifiable in terms of percentage of building weight since it is influenced by many factors, but its identification is extraordinarily significant from a seismic design perspective. We could also reasonably assume that the study might lead to a more efficient concept design from performance's point of view.

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