Site-Specific Seismic Analysis of Buildings Supported by Lightly Reinforced Precast Concrete Walls

Abstract

This paper aims to show the application of site-specific response spectra in the analysis of buildings that are supported by lightly reinforced precast concrete walls. Previous surveys on load-bearing precast reinforced concrete walls in multi-storey buildings in low-to-moderate seismic regions have found that many existing precast walls are lightly reinforced with a connection reinforcement ratio less than the wall reinforcement ratio. When these precast walls are subjected to reversed cyclic loads, the lateral response is typically controlled by rocking and the ultimate performance is governed by the ruptures of connection dowels. This paper uses moment–curvature analyses in combination with plastic hinge analyses to evaluate the force–displacement capacity of planar lightly reinforced load-bearing precast walls. The seismic performance of a building supported by these lightly reinforced precast walls can then be assessed by superimposing the capacity curve and the inelastic site-specific response spectra developed for the building site. The proposed analytical approach is illustrated through a case study building. By comparing a lightly reinforced precast wall with a comparable limited ductile reinforced concrete wall, it is also found that, although these two walls exhibit similar force capacities, the ultimate displacement capacity of the lightly reinforced precast wall is significantly lower. This finding highlights the potential seismic vulnerability of lightly reinforced precast walls in some existing buildings.