A performance based approach for the seismic assessment and rehabilitation of existing RC buildings

Abstract

Using the results of a past experimental project in which a non-ductile, seismically under-designed building was tested pseudo dynamically in its as-built configuration as well as in two conceptually different rehabilitated configurations, a method for a simplified seismic performance assessment, based on the standard Pacific Earthquake Engineering Research Centre (PEER) methodology, is discussed. The two retrofitting methods compared in the experimental activity were: Fiber Reinforced Polymer wrapping of all the vertical elements and r.c. jacketing of selected vertical elements. The experimental activity consisted in bi-directional pseudodynamic (PsD) tests at increasing Peak Ground Acceleration (PGA) levels on a full-scale specimen in the two configurations. For this specific study, the results of the tests were used to quantify the achieved improvements in terms of performance brought about by the two retrofitting strategies in the tested building. In order to do that, at first, the benchmark structure was converted into a real building of the same age, then the costs for rehabilitation and repair and the losses referred to the ‘realistic’ building were estimated with the advice of an Italian licensed practicing engineer, based on market values and current practice. Finally, the performance-based assessment exercise consisted into the evaluation of the costs associated to each rehabilitation measure and the expected losses during the remaining life-span of the building for all the defined limit states: these numbers represent a suitable performance indicator for a simple and straightforward comparison of the different retrofitting strategies.