Strut and Tie Models for Strength and Deformation of RC Members

Abstract

Strut and tie models (STM) that can be used to determine strength and deformation limits for reinforced concrete (RC) members are presented herein. Conventional STM have been used for strength design, but they cannot appropriately address the ductility of members that is important to ensure safety under severe cyclic loads. The proposed STM is constituted to address the end region of flexural members, including plastic hinge regions, and will be the basis for the calculation of deformation and corresponding shear strength as well. The behavior of each component of the STM is evaluated based on material properties and stress paths. The elongation of the tie element depending on crack spacing/width is obtained from the bond-slip relationship. The contraction of the strut element is simply determined from the properties of concrete. The presented STM will provide useful tools for both design and evaluation of ductility-required RC members.