Tension stiffening effects in reinforced concrete members

Abstract

This thesis is in two parts which are related by the common theme of tension stiffening. Part I develops the concept of a stress-strain envelope to model the behaviour of the concrete in tension below the neutral axis of a reinforced concrete beam. This is substantiated by an analysis of the data from fourteen test beams. The envelope concept is then applied to the calculation of the moment-curvature relationships for these beams, which are also compared with the test results .Part II presents an experimental investigation of the longitudinal reinforcement strain distributions in reinforced concrete tension members. Test results for fourteen specimens having various cross-sections and reinforcement types are presented, with the reinforcement strains being measured by strain gauging the reinforcement internally. The comprehensive analysis of the test results includes specific design recommendations concerning bond stresses at working loads. Suggestions are made for further work.