Shear behavior of shallow-wide beams strengthened by external SHCC jacket

Abstract

ABSTRACT Shallow wide beams in structural systems are a good solution for many architectural constraints. In addition, these beams give construction time saving because of the simplicity of formwork and reinforced placement. Structural deficiency arises in the ultimate shear capacity of such beams as some codes neglect the contribution of shear reinforcement. Shear strengthening by Strain-Hardening Cementations Composites (SHCC) in form of a 2-sided or u-shaped jacket along shear spans provides a reliable solution.SHCC is an engineered cementitious composite having far superior to conventional cement mortar and has ingredients to contribute most optimally and efficiently to the various properties. The objective of this research is to study the shear behavior of shallow wide beams strengthened in shear with external SHCC layers along with the effect of vertical stirrups on the shear strength of shallow wide beams. An experimental program consisting of eleven specimens divided into three groups has been carried out. The investigation focused on studying the shear behavior of shallow wide beam with and without stirrups, examining the effect of thickness and grade of SHCC as a shear strengthening technique with various jacketing patterns with and without inserted external stirrups. The experimental results are further compared with predictions of particular international code provisions. Based on the comparative analysis of the conservative code's predictions for shallow beams, a modification is proposed to improve the predictions of the Egyptian code’s provisions for ultimate shear. The suggested equations account for the shear span to depth ratio, longitudinal reinforcement ratio, size effect, jacketing confinement, inclination of the compressive stresses to the beam axis besides the concrete/SHCC grades.