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.

Seismic behavior of MSCSS based on story drift and failure path

“…Zhang et al (2005)] established a more realistic analysis model and studied the range of the optimal relative mass ratio and relative stiffness ratio of MSCSS to achieve the best vibration control under random wind loads. Later, Zhang et al (2009) studied the response of MSCSS under the action of simulated ground motion represented by static and non-stationary random processes. In the study, additional columns, as shown in Figure 1, are added above each MSCSS sub-frame to reduce the excessive bending moments in mega-beams so that the larger spans of the mega-beams can be achieved.…”

Dynamic Response of a Combined Isolation Based Mega-Substructure under Bidirectional Near-Fault Ground Motions

“…Shaking table tests of a normal reinforced concrete megaframe structure and a multifunctional vibration-absorption reinforced concrete megaframe structure were performed, and the dynamic characteristics, the seismic responses, and the failure mechanism of these two models under earthquake motions were studied [24]. Passive mega-substructure-controlled structures were presented, and a parametric study of their structural characteristics was performed [25][26][27]. A mega-substructure isolation system was developed, and shaking table tests of the isolated structure, lower substructure-consolidated structure, and the aseismic structure were carried out.…”

Dynamic Reliability Analysis of Mega-Sub Isolation System Under Random Ground Motion

“…Lan et al [3] proposed a multifunction mega-sub isolation structure, which has the function of the mass dampers and base isolation as well as damping energy dissipation. Qin et al [4,5] and Zhang et al [6,7] investigated the control performances of the mega-sub controlled structure with different control strategies. Seismic responses of the mega-sub controlled frame with friction damper were analyzed by Lian et al [8,9].…”