ABSTRACT

Due to the dynamic nature of progressive collapse, nonlinear dynamic (NLD) analysis following initial damage of columns or bearing walls is the most realistic approach to investigate the progressive collapse performance. However, the NLD analysis with typical finite-element-based numerical modeling is too computationally demanding and time consuming, and thus it is not widely accepted in practice. Rather, simplified approaches are preferred. Dynamic Load Amplification Factor (DLAF), defined as the ratio of the resistance to the applied constant load at the same deformation, can be easily used to convert nonlinear static results into NLD ones. DLAF can be determined either by curvefitting formula (DoD, 2010) or by energy-based approach (Dusenberry & Hamburger, 2006, Izzuddin, et al., 2008, Tsai & Lin, 2008). However, the former only works for structures with plastic hardening resistance and the latter ignores the damping.