Energy-based collapse assessment of complex reinforced concrete structures with uncertainties

Abstract

This paper presents an integrated approach for collapse assessment of complex reinforced concrete (RC) structures regarding the randomness in nonlinear behavior of concrete. The concerned uncertainty is quantified based on a stochastic damage model (SDM) of concrete in which the fracture strain in micro-level is modeled as a Gaussian random field. By integrating the SDM into refined finite element analysis, the stochastic collapse of high-rise RC buildings subjected to strong seismic actions can be numerically simulated. An energy-based dynamic instability criterion in identifying structural collapse is recommended to further assess the structural anti-collapse reliability. Using the criterion, the collapse-resistance performance for a certain structure can be quantitatively evaluated based on the probability density evolution method, by which the randomness propagation across multiple scales of concrete and the transformation of probability structure of structural responses can be fully addressed and represented. Numerical investigation in terms of a prototype RC frame-shear wall structure is carried out. It is indicated that the randomness from concrete may dramatically affect the collapse behavior of the structure, and even lead to entirely different failure modes.