Seismic resistance of a reinforced concrete building before and after retrofitting Part II: The retrofitted building

摘要

This paper deals with the evaluation of the seismic resistance of a reinforced concrete building after a seismic retrofitting that includes both a partial reinforcement of the existing structure and a base isolation system. The seismic performance of the building has been evaluated with reference to the collapse conditions. To this aim three-dimensional nonlinear static analyses have been performed and a procedure for the definition of simplified two-degrees-of-freedom nonlinear systems, equivalent to the base isolated building, has been assessed. The equivalent simplified systems allowed to perform a wide number of nonlinear dynamical analyses with reference to several seismic inputs. The ultimate capacity of the retrofitted building has been conventionally expressed in terms of the minimum PGA that causes the collapse of the building according to a prescribed design spectral shape.