The Quadrants Method: a procedure to evaluate the seismic performance of existing buildings

In this work a new simple procedure for the evaluation of the seismic performance is formulated. It combines the results of non-linear static analysis with a specific Limit State defined by inter-storey drift-based damage threshold and the seismic demand obtained from the inelastic design spectrum. With both values it is possible to define four zones in the capacity curve which characterizes four different seismic performances. The procedure is used to evaluate two reinforced concrete framed buildings, the first one consist in a typical lowrise building designed according to current Venezuelan codes; the second one is a four-storey building designed according to older code, whose had been damaged by fire. Results shown both cases do not meet the Quadrants Method criterion then they need to be redesigned. Redesigned buildings were submitted to a non-linear dynamic analysis, representative of three hazard levels associated with three Limit States. These redesigned buildings met all the objectives associated with the hazard levels, showing the efficiency of the method for the rapid evaluation of the seismic performance of existing buildings.