Date of Award
Doctor of Philosophy
Progressive collapse is a situation when one or more key structural elements fail resulting in the failure of adjoining structural elements and, in return, leading to partial or total collapse of the entire building. One method of reducing the likelihood of a progressive collapse situation is to have structures designed with high redundancy so that a higher level of force distribution can take place after the failure of key structural elements. For an accurate evaluation of the structural behavior in a progressive collapse scenario, a nonlinear dynamic analysis (NDA) that considers the geometric and material nonlinearity should be conducted. The goal of this evaluation is to assess whether or not the structure is likely to collapse. The procedure of performing nonlinear dynamic analysis to design structures to resist progressive collapse is complicated; therefore, engineers usually perform simplified static analyses as opposed to conducting computationally expensive dynamic analyses. Codes such as General Service Administration (GSA2003), Department of Defense (DoD2005), and Unified Facilities Criteria (UFC2009) allow three types of analysis in the alternate path method: linear static (LSA), nonlinear static (NSA), and NDA. In LSA and NSA, for considering the dynamic amplification effect, gravity loads are increased using a load increase factor (LIF). LIF is equal to two for LSA and NSA, based on GSA2003 and DoD2005. In UFC2009 and GSA2013, the LIF is calculated using code equations. Previous studies show these coefficients are very conservative. Finding the optimal load increase factor (LIF) for both LSA and NSA would be more cost effective in the design of structures to help them resist progressive collapse. In this study, by considering effective variables, the researcher attempted to find an optimal and reliable LIF for steel buildings.
dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.
Ghaffari, Yousef, "Improved Value For Load Increase Factor In Progressive Collapse" (2015). Electronic Theses and Dissertations. 1314.