Probability of collapse evaluation for high-rise reinforced concrete buildings in the event of near-fault earthquakes and soil-structure interaction effects

This paper presents a probabilistic evaluation of the seismic performance of 10, 20, and 30-story reinforced concrete buildings with dual systems located in Tehran, Iran, considering the effects of Soil-Structure Interaction (SSI). The buildings are designed according to the Iranian seismic code, and their nonlinear planar models are developed in OpenSEES, accounting for two fixed and flexible-base conditions. The concentrated plasticity approach is employed to simulate the nonlinear response of frame elements, while the displacement-based fiber elements are utilized to model the shear walls. The Winkler springs and dashpot technique was used to capture the uplift of the foundation in flexible-based models. The planar models are then subjected to nonlinear static and dynamic analysis, as well as Incremental Dynamic Analysis (IDA), followed by fragility assessment and collapse risk evaluation using the risk integral method. A suite of pulse-like and non-pulse near-field earthquakes is employed to account for the effects of impulsive characteristics of the ground motions on the performance of buildings with rocking foundation. The probabilistic assessment of building models was conducted based on FEMA P695 methodology. The results indicate that the performance of flexible-base buildings is improved for the strong earthquakes and pulse-like records. However, the advantages of foundation flexibility are diminished in taller buildings due to their larger weight and higher mode effects. The foundation rotation is found to be lower than the performance limits of the seismic code. Finally, the SSI exhibits varying effects on the collapse risk of buildings of different heights, with a positive effect on shorter buildings, whereas its impact on taller buildings depends on the expected seismic hazard level at the site.