Performance-Based Seismic Fragility Analysis of a Double-Tower Structure with a Large Podium.

Purpose: Considering the sudden change of the structure shape of a double-tower structure with a large podium (DTS), the mechanical properties of the structure under earthquake are extremely complex. Therefore, it is very important to evaluate the seismic fragility of new structures such as the DTS under different control schemes. This paper uses the seismic fragility analysis method based on IDA to study the seismic performance of the DTS. By comparing and analyzing the control effects of different control schemes, the advantages of composite passive control schemes are highlighted, which provides a theoretical basis for pre-earthquake disaster prevention and post-earthquake damage assessment of the DTS. Methods: With the aim of minimizing the mean–variance of the total vibration energy of the structure, the optimal control parameters of the energy dissipation damper are obtained by combining theoretical analysis with finite element simulation. Then the optimal arrangement scheme of the energy dissipation damper is determined by arrangement and combination. Considering that the previous structural performance level division methods cannot accurately reflect the results of the seismic fragility analysis of the DTS, the performance grade and damage grade of the structure were divided into five limit states and six damage degrees for the first time in this paper, and on this basis, the seismic fragility analysis of the DTS under two different control schemes was carried out based on IDA. Results: The response curves of each substructure of the equivalent single-DOF model are consistent with those of the multi-degree-of-freedom layer shear model (multi-DOF model), which indicates the validity and rationality of the equivalent single-DOF model are verified. Conclusion: The research shows that the equivalent single-DOF model of the DTS avoids a large number of iterative calculations, improves the calculation efficiency, retains the accuracy of the multi-DOF model, and has good applicability and rationality. In addition, the finite element simulation results show that the failure of the DTS under the two control schemes is caused by the failure of the isolation bearing. Compared with the LIC scheme, the CPC scheme improves the structure's seismic performance as a whole. [ABSTRACT FROM AUTHOR]