EFFECT OF SPACING OF TRANSVERSE REINFORCEMENT ON THE LAPPED SPLICED GFRP-RC COLUMNS SUBJECTED TO CYCLIC-REVERSED LOADS

摘要

Recently, the non-corrodible fibre-reinforced polymer (FRP) materials have been used successfully as reinforcement for concrete structures. However, the behaviour of glass (G) FRP-reinforced concrete (RC) columns under seismic loading has not been explored yet. This paper presents the results of an experimental program that investigates the contribution of GFRP transverse reinforcement to the confinement of concrete core in lap-spliced GFRP-RC columns. Three full-scale column specimens were constructed and tested to failure under quasi-static cyclic-reversed loads. All specimens were reinforced with GFRP longitudinal bars and transverse stirrups. The columns had 350-mm square cross section and 1850-mm cantilever length. Each column was cast on heavily steel-RC footing measuring 1400×1400×600 mm~3, which was constructed to simulate rotational fixity of the column and to force the failure to occur in the column. The splice length for each column was equal to sixty times the diameter of the longitudinal column reinforcement. The test variable was the spacing between the transverse GFRP reinforcement (75,100 and 150 mm). Test results are presented in terms of mode of failure, load-drift diagrams, energy dissipation, ultimate capacity and code comparison, if applicable. The results showed that, decreasing the spacing of spiral reinforcement improved both the strength and the deformability of the columns. Moreover, the requirement of the Canadian standard for FRP-RC buildings related to the amount of confinement provided by GFRP transverse reinforcement is adequate to ensure stability of the longitudinal bars.