Behaviour of Reinforced Concrete Joints

Abstract

<p>No rigorous explanation exists for the behaviour of reinforced concrete joints. The lack of understanding the complex interaction may account for continued use of inadequate joint details particularly for knee joints subjected to opening moments. The object of this research was to provide a better understanding of joint behaviour through a combined experimental and analytical investigation.</p> <p>In the experimental program, 6 specimens with different types of joint details were tested under opening moment. These details reflected recent recommendations by other investigators and some adaptations of their ideas. The results served as evidence of the ability to produce effective and simple details as well as serving as a basis for evaluating the reliability of the analytical model.</p> <p>A method of analysis has been developed using the finite element method to model the behaviour of reinforced concrete including the interactions between concrete and steel in the form of bond and dowel forces. One of the principle features of this method of analysis is the built in ability to trace the propagation, location and orientation of cracking. This feature was tested by comparing predicted behaviour of beams failing in shear and flexure with test results. Very good agreement with the well documented phenomena of various modes of cracking and failure provided evidence of the validity of the analytical method.</p> <p>The analyses of the joints reproduced cracking patterns and sequences as well as capacities which are quite close to the test results. The analytical information helped to identify the primary causes of failure of premature failure and thereby provided a more rational basis for suggesting alternate joint details which will behave much better than inadequate details which are currently recommended.</p>