Enhancing seismic performance of reinforced concrete dual wall-frame buildings: Integrating alternative modeling and design approaches

This study delves into two critical issues related to the seismic analysis and design of Chilean reinforced concrete dual wall-frame buildings. First, it evaluates the efficacy of Special Boundary Elements (SBEs) in shear walls, whose seismic performance enhancement remains uncertain despite recent (i.e., after the 2010 earthquake) mandates in Chile. Second, it investigates the relevance of explicit inclusion of slabs in 3D nonlinear models (in dual wall-frame buildings slabs are often not modeled for computational expediency). Various analytical models of a representative 16-story dual wall-frame archetype building are meticulously evaluated using Perform3D. Different vertical heights of the SBEs (ranging from 0 to 5 stories) and different values of the effective flexural stiffness of the slabs (ranging from 0 to 100% of the gross cross-section stiffness) are considered. Subduction ground motions representative of the Chilean seismicity are selected and scaled based on detailed seismic hazard analyses. Evaluation metrics include collapse fragility functions and 50-year collapse probabilities. Inelastic deformations in the shear walls are thoroughly analyzed. It was found that the effective flexural stiffness of the slabs has a non-negligible influence on the analytical collapse probability, and that SBEs do not provide ductility but they do reduce the collapse probability.