A new analytical procedure for the derivation of displacement-based vulnerability curves for populations of RC structures

A new procedure is proposed for the derivation of analytical displacement-based vulnerability curves for the seismic assessment of populations of reinforced concrete structures. The methodology represents an optimum solution compromising between reliability and computational efficiency. Adaptive pushover analysis is employed within a capacity spectrum framework of assessment, to determine the performance of a population of building models for increasing ground motion intensity. The building model population is generated from a single design through consideration of material parameter uncertainty, with design of experiment techniques used to optimise the population size. Uncertainty in ground motion is accounted for through the use of suites of accelerograms with characteristics that are representative of the hazard level associated with the performance level assessed in each vulnerability curve. The new homogeneous reinforced concrete damage scale, which is experimentally calibrated to maximum inter-storey drift for different structural systems, is used to determine the damage state of the building at the performance point. The results of the assessments are used to construct response surfaces from which the damage statistics forming the basis of the vulnerability curves are generated through re-sampling. The proposed methodology is illustrated for the case of low-rise, infilled RC frames with inadequate seismic provisions. The derived curves show good correlation with observational post-earthquake damage statistics.