Design, Optimization and Nonlinear Response Control Analysis of the Mega Sub-Controlled Structural System (MSCSS) Under Earthquake Action

Abstract

The lately proposed mega sub-controlled structure (MSCSS) remarkably improved the seismic resistance ability and reduced vibration effects much more than the mega substructure (MSS). However, the controlling effectiveness and its optimization remain a significant concern. In this paper, a new configuration of MSCSS is analyzed in which viscous dampers are optimally arranged between mega-frame and substructural frame and optimal damper parameters are investigated. Also, rubber bearings are designed and introduced at the top of the additional column to ease the horizontal constraints between the additional column and mega-floor beam and improve the structural design of MSCSS, so that the structure has a larger span and further reduces the structural response. The result showed that optimal parameters of the damper and its optimal arrangement have a significant influence in the control effectiveness of MSCSS. Furthermore, the addition of a rubber bearing at the top of the additional column improves the mechanical behavior of the column and further reduces the acceleration response of both the mega-frame structure and the substructure. This paper also shows that the percentage reduction of the acceleration is more within the substructure than at the mega-frame structure. The seismic response of this structure under El Centro is less than the Taft (NE) wave and the percentage reduction is more under the Taft wave than under the El Centro wave.

Response control analysis of a new mega‐subcontrolled structural system (MSCSS) under seismic excitation

“…The analytical model of the newly proposed MSCSS is represented as a simplified three-lumped-mass model based on the two-lumped-mass model presented for base isolation structures by Kelly, who employed an equivalent linear model to represent the hysteretic behavior of the isolation system. [27,28] The elevation view along with plans of different sections in the traditional MSS, improved MSCSS [9] and newly proposed MSCSS configurations are shown in Figure 1.…”

“…F I G U R E 1 Configurations: (a) MSS, (b) MSCSS by Abdulhadi et al, [9,10] The dynamic equation of motion for the superstructure (i.e., above the mid-story isolator) for the proposed MSCSS under seismic excitation can be expressed as…”

“…Fragility analysis further showed that the improved MSCSS exhibits better resilience to strong seismic excitations, as the MSCSS requires a high-intensity earthquake to reach moderate damage limits, whereas the MSS reaches its collapse damage limit under a high-intensity earthquake. [9,10] Under a collapse-prevention performance level, the failure probability of the MSCSS is 30% lower than that of the MSS, and the failure probability of the mega-structure is 50% lower than that of its substructure. MSCSS demonstrated a greater than 10% response control rate and an approximately 20% base shear control rate under long-period ground motions.…”

“…For this purpose, inverted V-bracing (chevron) and LRBs are designed and introduced into the structure to study its structural response control. Finite element analysis is carried out on the proposed MSCSS by using ABAQUS, and the results for the traditional MSS, MSCSS and improved MSCSS [9] are compared to enhance the understanding of the complicated nature of the MSCSS, which will have a significant impact on future research. Additionally, an innovative and improved MSCSS configuration with a mid-story isolation system is proposed, resulting in a significant improvement in the total structural response.…”

Seismic behavior of MSCSS based on story drift and failure path

“…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. Fan et al (2020) and Abdulhadi et al (2020) have demonstrated that if lead rubber bearings (LRBs) are installed between the additional columns and the mega-beams as shown in Figure 1, that is to release the connections between sub-frames and the upper mega-beams, the seismic performance of MSCSS can be further improved. In the past, most studies on MSCSS used the story drift ratio (SDR), acceleration, or energy dissipation as indicators to measure the effect of vibration control (Zhang et al 2005(Zhang et al , 2009Limazie et al 2013;Fan et al 2020).…”