Evaluation of Seismic Fragility Analysis of the Mega Sub-Controlled Structural System (MSCSS)

Abstract

The improved mega sub-controlled structure system (MSCSS) significantly reduced the building responses and improved the control effectiveness as compared to conventional mega substructure (MSS). However, since the MSCSS is designed to resist future earthquakes, the seismic risk assessment of the structure remains a significant concern. In this study, the seismic risk analysis of MSCSS is performed to probabilistically compare the building performance and its resistance to future earthquake damage at certain categories of limit states (LSs), which include category one (slight damage, moderate damage, and collapse damage LS) and category two (damage control and collapse prevention). The comparison is realized with the result of the traditional MSS. The probability of exceedance of the above damage LS for a particular ground motion (GM) intensity (i.e. Sa (T1,5%)) is evaluated to assess and compare the vulnerability of these buildings. The evaluation is done through developing fragility curves and relationships for MSCSS and MSS. The result showed that the improved MSCSS has strong seismic resistance ability and provides a better response from a nonlinear analysis result. Furthermore, the fragility curve of moderate and collapse damage LSs indicated that MSCSS requires higher GM intensity to reach a moderate and collapse damage LS than MSS. That means MSCSS is the most stable with a significant difference as compared to its counterpart. This is also true for the second category of LS, that is, damage control and collapse prevention. While at the slight damage LS, both the MSCSS and MSS require approximately the same GM intensity to reach a slight damage LS, as the difference is not significant.

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.…”

“…Configurations: (a) MSS, (b) MSCSS by Abdulhadi et al, [ 9,10 ] and (c) newly proposed MSCSS. Dimensions are in meters…”

“…For further confirmation, configuration 1 (proposed by Abdulhadi et al [ 9,10 ] ) and configuration 13 are analyzed under the service load, as LRBs show improved performance under loading conditions. Figures 9–11 clearly indicate that configuration 13 has a much better controlled structural vibration response under seismic excitation than configuration 1.…”

“…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.…”

“…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.…”