Estimation of inelastic displacement ratio for base‐isolated structures |
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| Authors: | Saman Yaghmaei‐Sabegh Sina Safari Karim Abdolmohammad Ghayouri |
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| Affiliation: | Department of Civil Engineering, University of Tabriz, Tabriz, Iran |
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| Abstract: | This study develops a straightforward approximate method to estimate inelastic displacement ratio, C1 for base‐isolated structures subjected to near‐fault and far‐fault ground motions. Taking into account the inelastic behavior of isolator and superstructure, a 2 degrees of freedom model is employed. A total of 90 earthquake ground motions are selected and classified into different clusters according to the frequency content features of records represented by the peak ground acceleration to peak ground velocity ratio, Ap/Vp. A parametric study is conducted, and effective factors in C1 (i.e., fundamental vibration period of the superstructure, Ts; postyield stiffness ratio of the superstructure, αs; strength reduction ratio, R; vibration period of the isolator, Tb; strength of the isolator, Q; ratio of superstructure mass to total mass of the system, γm) are recognized. The results indicate that the practical range of C1 values could be expected for base‐isolated structures. Subsequently, effective parameters are included in simple predictive equations. Finally, the accuracy of the proposed approximate equations is evaluated and verified through error measurement, and comparisons are made in the analyses. |
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| Keywords: | base‐isolated structures frequency content inelastic displacement ratio performance‐based analysis |
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