Vamvatsikos D., Zeris C. (2010). Seismic performance sensitivity and uncertainty of an RC building due to random vertical loads and accelerations. Proceedings of the 3rd International fib Congress and Exhibition, Washington, D.C.
Abstract | We investigate the influence of the uncertain value of the gravity loads and the vertical ground motion component on the seismic performance of a nonductile reinforced concrete building. Seismic guidelines typically enforce the use of the Gκ + 0.3Qκ combination, where Gκ, Qκ are the characteristic dead and live loads, respectively. However, their true values and their influence to the seismic response are not known. Using a typical existing five-story reinforced concrete building, we employ incremental dynamic analysis to evaluate the seismic performance under probabilistic load distributions in combination with the use or not of the vertical component of ground motion. Multiple accelerograms are scaled to several levels of intensity, both in the horizontal and in the vertical sense, to evaluate the building capacity in limitstates ranging from serviceability to global dynamic instability and structural collapse. Thus, it is shown that the highly variable live loads tend to increase the response uncertainty especially when they dominate over dead loads. On the other hand, the effect of vertical accelerations depends on the magnitude of the gravity loads, with higher loads causing significant capacity reductions across all limit-states considered.