Enhancement of seismic behaviour of precast beam-to-column joints using engineered cementitious composite

Seismic activities can cause considerable damage to the integrity of the reinforced concrete and precast concrete structures, particularly in the beam-to-column joints. This article investigates the impact of using engineered cementitious composite (ECC) with different types of fibres on the performance behaviour of novel precast beam-to-column joints subjected to cyclic loading. Six samples of the novel precast hybrid joints, including one sample with a conventional joint, were tested to evaluate the seismic behaviour of the joints. The investigated precast joints were cast using ECC with 2% volume fraction of polyvinyl alcohol fibre (with two different aspect ratios), polyethylene fibre, hooked-end steel fibre, and hybrid fibre, while normal concrete was used to prepare the conventional monolithic joint. The seismic behaviour of the precast joints exhibited better performance than the conventional monolithic joint. This is as a result of the higher tensile and flexural strengths of the ECC fibres, better mechanical bridging in the crack area, adequate amount and distribution of the fibres, good bonding in the ECC produced, the increasing resistance to slippage for the reinforcing bars, and avoidance of the spalling concrete in the joint area, which may cause shear failure. The deformation capacity of the precast joints was 12.5% higher than that of the conventional monolithic joint. In addition, the ductility values and the hysteretic energy dissipations of the precast joints were 15.69–43.14% and 25.40–49.18%, respectively greater than that of the conventional monolithic joint. Furthermore, beam flexural failure was observed for the precast samples and there was less damage compared with the monolithic sample. Thus, the novel precast joints can be potentially implemented to withstand high earthquake activities due to their superior seismic performance.