Shear behavior of ultra-high performance concrete corbels：Experimental study and modified strut-and-tie model

In this study, a static loading test was performed to examine the shear behavior of twelve ultra-high performance concrete ( UHPC) corbels. The impact of key parameters, such as shear-span ratio, steel fiber volume ratio, and stirrup reinforcement ratio on corbels' mechanical behavior, were explored. The test findings reveal that the cracking load of UHPC corbels is significantly higher than that of the corbels without steel fiber, and the failure mode changes from shear failure to flexural failure. Reducing the shear-span ratio and increasing the stirrup reinforcement ratio substantially improved the shear capacity of the corbels. Furthermore, a modified strut-and-tie model was developed for predicting the shear capacity of UHPC corbels. A shear test database for UHPC corbels was compiled to validate the accuracy of the proposed method. The model showed strong agreement with the test results and demonstrated satisfactory adaptability. Finally, four other models from national standards and academic proposals were evaluated under the same conditions. The proposed model showed superior correlation with the experimental data, suggesting its potential to improve the design and application of UHPC corbels in practical engineering contexts.