Unified Softened Membrane Model for Torsion in Hollow and Solid Reinforced Concrete Members: Modeling Precracking and Postcracking Behavior

Abstract

The softened membrane model for torsion (SMMT) was the first rational theory to incorporate the precracking and postcracking torsional behavior of solid RC members. A series of theoretical and experimental investigations were conducted in Taiwan to extend the SMMT to hollow RC members. This paper proposes a generalized SMMT based on the results of these investigations, determines the constitutive relationships of concrete for thin- and thick-walled hollow RC members, and develops a unified SMMT theory for hollow and solid RC members. The proposed SMMT for hollow RC members (SMMT-H) is also employed to derive a rational