Effect of joint width on shear behaviour of wet joints using reactive powder concrete with confining stress

Abstract

The filling concrete in a wet joint without steel reinforcements of precast segmental bridges is one of the weakest part of the bridges under shear. The joint width tends to be narrowed in construction, but structural shear behaviour might be different when the joint geometry varies. Therefore, it is crucial to study the shear behaviour of wet joints with various joint widths. In this study, the shear behaviour of wet joints with confining stress induced by the effect of joint width was investigated via experimental research and numerical simulation. A calculation model was proposed to evaluate the shear capacity of wet joints considering the effect of joint width. The experimental results revealed different failure modes of wide and narrow joints with a change in the force transmitting path. The wide joint exhibited brittle failure with one diagonal crack, whereas two symmetrical cracks were observed in the narrow joint before its failure. The load–displacement curve of the narrow joint exhibited two fluctuations, whereas that of the wide joint exhibited only one. These fluctuations represented the number of the cracks occurring in the joints. The numerical results demonstrated that the rotation effect, which was induced by different joint widths, caused a longer crack in the wide joints. Additional concrete was involved in the shear load transfer because the vertical area of shear component along the crack expanded. The average ratio of the calculations from the proposed formula to the results of this study and previous researches was 1.14, which showed to be accurate to predict the shear capacity of the wet joints.