Seimic Risk Analysis of Frames with Uncertain Support and PR Connection Conditions

Abstract

A hybrid reliability evaluation procedure is proposed to estimate the risk of steel frames considering the rigidity of connection and supports as accurately as possible. Nonlinearities due to geometry, material, partially restrained (PR) connections, and flexible supports are considered in the proposed algorithm. The unique feature of the algorithm is that the earthquake loading can be applied in the time domain, providing an alternative to the random bigration approach. The proposed algorithm intelligently integrates the concepts of the finite element method, the response surface method, the first order reliasility method, and the iterative linear interpolation scheme. The algorithm is verified using Monte Carlo simulation. With the help of an example, it is shown that the proposed algorithm can be used to estimate risk for both the serviceability limit state may become supports to be rigid and fesigning the frame for the strength limit state may not be appropriate. The flexibility of connections and supports and the uncertainty in modeling them have a considerable influence on the overall behavior of frames, particularly under seismic loading. An efficient, robust, and accurate method is proposed to evaluate the reliability of such frames.