Seismic performance of precast posttensioned concrete frame under low reversed cyclic loading

Abstract

SummaryA precast posttensioned (PT) concrete frame, which consists of PT composite beams, precast columns, and cast‐in‐place (CIP) core regions, was developed as an emulative structure in this paper. Cyclic loading tests were conducted on two 1/3‐scale frames, including a precast frame and a CIP control specimen, to investigate the seismic performance. The axial compression ratios of the specimens were 0.4 and 0.3 for the interior and exterior columns, respectively. The test results showed that the precast frame failed in mixed sidesway mechanism which was similar to that of the CIP control specimen. The hysteresis loops of both the precast and CIP frames were pinched but relatively plump, which exhibited good energy dissipation. The loading capacity of the precast frame was comparable to that of the CIP control specimen, and the deviation of average value was less than 5%. The average ductility of the roof, first interstory, and second interstory of the precast frame was 4.18, 4.24 and 4.18, respectively, which was approximate to that of the CIP control specimen. The stiffness degradation of the precast frame was also found to be quite similar to that of the CIP control specimen. Based on the test results, a degenerated four‐linear restoring force model was developed.