Experimental and theoretical model study on shear performance of ultra-high performance concrete corbels

Through static tests on 12 ultra-high performance concrete (UHPC) corbels, this study investigates the influence of key parameters, such as shear span-to-depth ratio, steel fiber volume ratio, and stirrup reinforcement ratio, on the shear behavior of corbels. The results indicate that, compared to high performance concrete corbels without steel fibers, UHPC corbels exhibit a significant increase in cracking load, accompanied by a transition in failure mode from shear failure to flexural failure. Reducing the shear span-to-depth ratio and increasing the stirrup reinforcement ratio enhance the shear carrying capacity of the corbels. Collected experimental data of UHPC corbels were used to evaluate the applicability of shear capacity calculation formulas for corbels in the specifications GB 50010—2010 ‘Code for design of concrete structures’ and JGJ / T 465—2019 ‘Standard for design of steel fiber reinforced concrete structures’, as well as the theoretical models. It is observed that the existing models tend to be conservative, resulting in underestimated predictions of UHPC corbel capacity. Based on this assessment, an improved strut-and-tie model suitable for predicting the shear capacity of UHPC corbels was proposed. The model’ s average ratio of computed results to the experimental results collected in this study is 1. 15, with a coefficient of variation of 0. 07. The improved model demonstrates better accuracy and consistency compared to existing computational models, serving as a reference for UHPC corbel design. © 2024 Science Press. All rights reserved.