Modelling of post-tensioned precast reinforced concrete frame structures with rocking beam-column connections

2004 NZSEE Conference ABSTRACT: Recent earthquakes have identified that buildings designed to a performance based criteria need not only resist the ground excitation but remain, in many situations, undamaged once ground motions have abated. One promising approach is the use of post-tensioned frame structures assembled from precast reinforced concrete members. A modelling approach has been developed which provides for the accurate simulation of the developed compression zone and accounts for the shift of the neutral axis in the contact area over the duration of earthquake motion. Furthermore, the beam elongation effects are captured as well as the effects on the structure due to the lengthening of the post-tension tendons. A new multi-spring contact element has been developed and included in the finite- element program RUAUMOKO. The distribution of the stiffness along the contact area of the rocking elements is calculated based on a number of different integration schemes. The model is compared with experimental displacement controlled tests undertaken with beam-column subassemblies and experimental dynamic tests of a multi-storey frame structure.