Non-linear dynamic analysis of an infilled RC building for increasing seismic hazard levels

A seismic assessment study on an Italian school with reinforced concrete (RC) structure built in the early 1960s is presented herein. The seismic performance of the building is evaluated, via time-history dynamic analysis, by jointly examining the response of the structural members and the masonry infills and partitions. In order to attain a comprehensive evaluation, the analysis is extended to four supplementary seismic hazard levels, identified by 50%, 40%, 30% and 20% probabilities of being exceeded over the reference structural lifespan, VR, in addition to the four ones assumed by default by the Italian Technical Standards, with 81%, 63%, 10% and 5%/VR probabilities. The results highlight unsafe stress states in a non-negligible percentile portion of columns and beams, and damaged response conditions of masonry panels beginning from the input action with 30%/VR probability. The number of structural members in unsafe conditions and significantly damaged panels increases to about 50% and 45%, respectively, for the action scaled at 20%/VR probability. This prompts to extend the assessment analysis of RC infilled structures also to an intermediate hazard level, situated in the 30-20%/VR exceedance probability range.