Questions on Shear Behavior of Structural Concrete and Answers Provided by Mechanical Models. The Challenge of Performance-Based Shear Design

Abstract

The shear behavior and strength of reinforced and prestressed concrete structures is difficult to predict due to the complex resistant mechanisms that are mobilized and the different types of failure that can occur. This has given rise to many of the simplified formulations previously developed for shear calculation being empirical in nature, which lack a clear theoretical basis and they do not provide qualitative information on structural behavior. Therefore, performance-based design becomes difficult using such types of formulations. In this paper, some questions about shear behavior and design are raised, apparently without an immediate answer from the performance point of view, and possible answers based on structural mechanics are provided. The physical phenomena that determine the shear behavior, the resistant mechanisms that are developed, the fundamental parameters that govern them, to what extent they influence and how they are contemplated in some simplified formulations are analyzed. The importance of mechanical models is raised and some examples of how these models can be naturally adapted to multiple project situations, evaluation and reinforcement of existing structures are shown.

Theoretical Model for the Shear Strength of Prestressed Concrete Beams with FRP Tendons

“…The compressed block at the end of the crack is very small, resulting in a very low value of Vc. However, the friction force along the second branch of the critical shear crack as a part of the aggregate interlock, whose vertical component is considered to be incorporated as Vw (Marí 2023).…”