Recent earthquake engineering research undertaken at the University of Canterbury has aimed at determining whether New Zealand designed and built precast concrete structures, which incorporate precast concrete hollow-core floor slabs, possess inadequate seating support details. A full scale precast concrete super-assemblage was constructed in the laboratory and tested in two stages. The first stage investigated existing construction and demonstrated major shortcomings in construction practice that would lead to very poor seismic performance. This paper presents the results from the second stage that investigates the efficiency of improved construction details on seismic performance. The improved details consist of a simple (pinnedtype) connection system that uses a low friction bearing strip and compressible material for the supporting beams together with a 750mm wide timber infill between the perimeter beams and the first precast floor unit. Test results show a marked increase in performance between the new connection detail and the existing standard construction details, with relatively small amounts of damage to both the frame and flooring system at high lateral drift levels. The results show that interstorey drifts in excess of 3.0% can be sustained without loss of support of the floor units with the improved detailing The overall performance of the super-assembly is determined in terms of the hysteretic performance and the fragility implications in terms of the drift damage are classified. Recommendations for future design and construction are made based on the performance of the super-assemblage test specimen and a probabilistic fragility analysis.
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