THEORETICAL SOLUTIONS OF SHEAR STRENGTH OF R/C MEMBERS CONSIDERING EFFECT OF LONGITUDINAL REINFORCING BARS AND AXIAL FORCE, AND CONTRIBUTION OF PARAMETERS

Abstract

In "Design Guidelines for Earthquake Resistant Reinforced Concrete Buildings Based on Inelastic Displacement Concept", published in AIJ, the shear strength formula does not consider the effect by longitudinal reinforcement ratio and axial force that is observed in numbers of empirical examinations. This is due to the assumption that longitudinal reinforcement bars do not yield. In this paper, we rebuild theoretical fomula limited to truss mechanism based on upper bound theorem by considering the fracture mechanism putting yield limit of longitudinal reinforcement, that is same as Doi assumed. The solutions can prove the rise of shear strength by rise of shear reinforcement, longitudinal reinforcement, or axial force. Those can also prove that the influence of axial force changes according to the amount of longitudinal reinforcement that is shown in past empirical data. By introducing the effective coefficients to each parameters of the solutions and letting the coefficients reflect past empirical data, we found out that longitudinal reinforcement and axial force contribute to shear strength, but do not contribute than shear reinforcement.