Analytical Extension of Higher Modes Participation in The Estimation of Seismic Response of Tall Hybrid Framed Tube Structures comprising Mega Zipper Elements

Abstract

This paper presents a computational approach to the analytical performance of the modal pushover method (MPA) in predicting nonlinear response parameters of tall buildings comprising hybrid framed tube with large-scale zipper elements. The accuracy of the results based on MPA is evaluated by comparing the benchmark responses obtained through conducting two sets of nonlinear time history analyses (NLRHA). Also, the effects of higher modes on the structural response parameters are measured by considering three computational vectors of the ordered lateral loading prepared according to the participation of the basic mode, as well as the first 3 and 5 transitional modes, separately. In this study, the determination of the target displacement in MPA was set based on the results of NLRHA under two groups of near and far-field records. The variation range of response parameters of the three high-rise 30-story studied structures was evaluated based on conducting a series of MPA as well as NLRHA analyses. The structural system of the first studied model is a combined framed tube structure. The second and third introduced studied models contain a multi-story arrangement of large-scale zipper elements on the basic skeleton by connecting the aforementioned zipper elements to the columns on the ground floor. The multi-story arrangement of large-scale zipper elements has been aimed at preventing the formation of an intensive expanded plastic mechanism and avoiding the possible buckling mode in the columns of the lower floors. The computational outputs of the MPA are compared with the results of the NLRHA (as exact values) and the standard error percentage is estimated. Evaluation of the results presented in this study demonstrates the relatively desirable computational capability of the MPA method in predicting the behavior characteristics of tall building structures with a symmetric and regular rigid skeleton at plan and height. Moreover, it was observed that the presence of large-scale zipper elements in the resistant system could reduce the seismic response parameters and also relatively increases the overall dynamic stability of the high-rise structural skeleton.