Simplified non‐linear dynamic analysis of base isolated buildings subjected to general plane motion

Considers hysteretic non‐linear models for modelling horizontal force‐displacement characteristics of an isolation system subjected to general plane motion. Simple close form solution of the stiff differential equation of hysteretic model for forces mobilized in the non‐linear elements of the base isolation system are obtained. Simulates experimental shear force‐displacement loops obtained from the bi‐axial tests by different investigators. Both the experimental and the simulated hysteresis loops are found to be in good agreement. Develops a unified solution algorithm for computation of response of different types of base isolated buildings, considering non‐linear behaviour of the isolation systems, subjected to multi‐directional motion. The solution algorithm is based on the implicit‐implicit partitioned Newmark’s method in predictor‐corrector form. Response of the base isolated symmetrical building as obtained from the solution algorithm and the computer programs developed are in good agreement with that obtained from the more complex numerical studies reported in the literature. Response of a three storeyed symmetrical building isolated by pure friction isolators and laminated rubber bearings has been obtained using this simple yet accurate solution algorithm.