The risk for progressive collapse of RC frame structures located in seismic areas in Romania

In this study the risk for progressive collapse of RC framed buildings located in seismic areas in Romania is investigated. Structures with three, six and ten stories, each in turn are designed for three distinct seismic zones: low (ag=0.08g), moderate (ag=0.16g) and high (ag=0.24g). Using the provisions provided by the GSA (2003) Guidelines, a nonlinear dynamic analysis is carried out first in order to establish the risk for progressive collapse of the models under investigation. It is shown that all the structures are not expected to fail when subjected to abnormal loading (sudden column removal). A nonlinear incremental dynamic analysis is conducted next in order to estimate with the maximum accuracy the ultimate load bearing capacity to progressive collapse of the damaged models. Based on the capacity curves provided by this procedure, it is shown that all the structures are capable of sustaining a higher load than the standard GSA loading before failure. Using these capacity curves, the influence of the seismic design on the progressive collapse resistance is quantified as well