The influence of axial load variation on the seismic performance of in-plan irregular RC buildings

Abstract It is well known that the axial load plays an important role in the evaluation of the structural capacity of RC columns. In existing buildings this problem can be even more relevant than in new ones, since the material can easily present poor mechanical properties. The paper is aimed at the investigation of the role of the axial load variation on the seismic capacity of RC columns, evaluated in terms of limit chord rotation. The study is performed with reference to an RC building case-study, which is a doubly symmetric 4-storey RC building, where the in-plan irregularity is given by an inhomogeneous distribution of the concrete strength of the columns at the first storey. The axial load variation affects both the seismic response and capacity of the case-study; the seismic performance of the case-study is therefore investigated as a function of the axial load variation.