A New Proposed Passive Mega-Sub Controlled Structure and Response Control

Abstract

It is still a serious challenge for structural engineers to effectively reduce the seismic responses of tall and super tall buildings to further improve these structural safeties. In order to solve this problem, in this article a new kind of structural configuration, named passive mega-sub controlled structure (PMSCS), is presented, which is constructed by applying the structural control principle into structural configuration itself, to form a new structure with obvious response self-control ability, instead of employing the conventional method. In the analysis of PMSCS the equations of motion of the seismically excited system are developed, based on a realistic analytical model of the complete mega-structural system. Expressions of the displacement and acceleration response of the structure, resulting from simulated earthquake ground motions represented by stationary and nonstationary random processes, are derived. These responses are then determined for both the PMSCS and its conventional mega-sub structure (MSS) counterpart, whose configuration was modeled after the traditional mega-frame that was used in the construction of the Tokyo City Hall. A parametric study of the structural characteristics that influence the response control effectiveness of the PMSCS is presented and discussed. The region over which these structural characteristics yield the optimum seismic response control of the PMSCS is identified and serves as a very useful design tool for practitioners. The study illustrates that the proposed PMSCS offers an effective means of controlling the seismic displacement and acceleration response of tall/super-tall mega-systems. It also overcomes shortcomings exhibited in earlier proposed mega-sub controlled structural configurations.