Prediction of behavior of UHPC beams based on truss models

Abstract

There is renewed interest in studying the shear mechanism of concrete beams. Ultra-High Performance Concrete (UHPC) is an advanced material with great mechanical properties, making it widely adopted in engineering structures. In this paper, a truss model analogy is used to study the behavior of UHPC beams under point loads. The model is developed based on a variable angled truss where the UHPC tensile behavior is considered. The proposed truss model is validated with UHPC beam experimental results database collected from available literatures. The results indicate that the behavior of the UHPC beam is well explained by the truss model. A parametric study on the effect of shear span-to-depth ratio, UHPC compressive strength, longitudinal bottom reinforcement ratio and steel fiber content on the beam load carrying capacity is conducted based on the truss model. The results of parametric study are used to develop prediction equations for UHPC beam load carrying capacity in this study. Finally, a comparison between the proposed prediction equations and existing prediction equations in available literatures is conducted. The results indicate that the proposed equations slightly underestimated the experimental value with relatively lower coefficient of variation and simpler equation format, indicating a potential engineering application.