Collapse assessment of substandard concrete structures for seismic loss estimation of the building inventory in the UAE

Abstract

Regional earthquake loss estimation systems describe the probability of losses that could happen by a seismic hazard to a certain region. In order to develop a loss estimation system for a region, the vulnerability characteristics of the exposed structures should be integrated with earthquake hazard and the inventory of the built environment. The accurate definition of structural collapse under earthquake loads is essential for deriving reliable vulnerability functions. In this study, the collapse of concrete buildings is described in terms of both global structural response and member failure, including shear failure modes. Experimentally verified shear strength models that effectively consider the reduction of shear strength with the concrete degradation under cyclic loading are implemented in a post-processor to monitor the shear supply-demand response of concrete structures under earthquake loads. A wide range of reference structures with diverse lateral force resisting systems and building heights is selected to represent substandard buildings in the UAE. Detailed fiber-based numerical models and a diverse set of earthquake records representing different seismic scenarios in the study region are employed in dynamic response simulations at various levels of ground motion intensities up to collapse. The effectiveness of the adopted shear strength models in predicting the brittle failure modes of substandard concrete buildings is demonstrated in this study. It is concluded that shear modeling is essential for the reliable earthquake loss estimation of pre-seismic code buildings. The advanced vulnerability functions confirm the need for mitigation strategies to reduce the earthquake losses of the substandard building inventory in the study area. This comprehensive study represents a step forward for the development of a reliable loss estimation system in the UAE and the surrounding region.