Seismic Analysis of a Low-Damage Precast Wall with End Columns (PreWEC) Including Interaction with Floor Diaphragms

Abstract

The 2010/2011 Canterbury earthquakes have demonstrated that low-damage structural systems should be adopted to improve the seismic performance of concrete buildings and to reduce the economic and social impact of building damage in future earthquakes. One such low-damage structural system is selfcentering precast concrete walls that utilise jointed construction and unbonded post-tensioning. A new low-damage concrete wall system that uses this self-centering design is PreWEC, which consists of a precast wall with end columns. The PreWEC system was designed to overcome the deficiencies of previous low-damage wall systems by increasing the moment capacity in a cost effective manner, so that the PreWEC system is comparable to traditional reinforced concrete construction in addition to providing superior seismic resilience. It is important that when a building is constructed using a low-damage wall system, its seismic performance, including the self-centering capability, is not compromised by damage caused to other structural elements when the building is subjected to an earthquake input motion. Similarly, it is important to avoid damage occurring during excitation that arises from interaction between the wall system and other structural elements. Experimental and analytical validation of the PreWEC system is summarised in addition to details of analytical studies that were performed to examine the interaction between the PreWEC wall, the floor diaphragms and gravity columns, as well as the seismic response of a prototype building that included PreWEC walls. Recommendations are presented to improve the seismic design practice for low-damage concrete buildings with specific consideration to the wall-to-floor interaction.