Modeling of Precast Building Frames for Seismic Response Analysis

Precast beam–column connections have been the subject of numerous experimental studies examining their performance under seismic loading, but investigations into the performance of the entire precast concrete frame structure incorporating these connections have not received as much attention. The seismic behavior of a 10-story precast concrete building frame is investigated with respect to those of a monolithic building frame. The effect of different types of possible modeling of the precast frame on its seismic behavior is studied.

For this purpose, 12 types of modeling of the beam–column joint were considered. The responses derived from different types of frame modeling are compared to identify the best model to adopt for the seismic analysis of precast building frames. Three hysteresis effects, namely isotropic, kinetic, and Takeda, are included in the study. The efficacy of each type of hysteretic effect is evaluated for both monolithic and precast frames. For the nonlinear seismic analysis, the backbone curves describing the moment-rotation relationship of the precast and monolithic joints are taken from the existing literature. Two types of precast joints, namely, emulated and non-emulated joints, are investigated.

For comparison of results between various cases, the average responses obtained from an ensemble of seven earthquake records are used. The responses include maximum base shear, peak top story displacement, maximum inter-story drift (MIDR), and absolute maximum acceleration. The results of the study indicate that the seismic analysis of a monolithic frame using standard modeling leads to an underestimation of the peak top story displacement and MIDR of the frame.

The seismic performance of the precast concrete frame is observed to be the same, if not more, as compared to that of the monolithic frame.