Experimental Investigation of Dapped Ends with Diagonal Reinforcement

Abstract

Reinforced concrete dapped-end connections are susceptible to formation of inclined cracks at the reentrant corner under service conditions. As these connections also work with high shear stresses, they require a high amount of reinforcement to ensure sufficient load-bearing capacity. To deepen the understanding of this topic, an experimental campaign of eight large-scale dapped-end connections featuring diagonal reinforcement is presented. These specimens, which are among the largest available in the literature, are similar in size to the dapped ends typically used in bridges. The test series captures both flexural and shear failures of dapped ends. The crack displacements, crack patterns, and elongation of main reinforcement are reported, with 56 continuous measurements of deformations. The test results of this study are used in conjunction with a similar study on specimens with orthogonal reinforcement to investigate the impact of reinforcement layout. For the same amount of dapped-end reinforcement, specimens with diagonal reinforcement are considerably stronger than the corresponding connections with orthogonal reinforcement. For both reinforcement layouts, the crack widths exceeded typical code provisions under service conditions.