Comparison of capacity curves of reinforced concrete buildings using ADINA moment-curvature element and SAP2000 lumped plasticity model

Abstract

One of the most important steps in the establishment of the capacity curve using pushover analysis is setting up reasonable member nonlinear properties that control the inelastic behavior of reinforced concrete (RC) members. The length of the plastic hinge is one of the major effective parameters in such type of analysis when using lumped plasticity models. In this study, the finite element program ADINA which has the capabilities in defining the non-linear properties through the moment-curvature for element, without the need to define the plastic hinge length, was utilized to obtain the capacity curve for three RC buildings. Also, the capacity curve was obtained using the user-defined non-linear hinge properties in SAP2000 software in which the nonlinear elements are defined by assigning plastic hinges at the ends of RC members. The potential differences between capacity curves obtained using the user-defined hinge properties by SAP2000 and the moment-curvature element in ADINA were investigated. Two four-storey and one eight-storey RC frames with different ductility were considered to represent low to medium rise buildings. The results of analysis showed that the base shear capacity obtained by SAP2000 model for different plastic hinge length values were almost identical and the base shear value obtained by ADINA model was little lower than that obtained by SAP2000 models, the variation in base shear capacity ranged between 3.55% and 6.53%. However, the displacement capacity was significantly affected by the value of the plastic hinge length.