Modelling of mechanical behaviour of concrete structures

Abstract

<p>This thesis deals with numerical modelling of mechanical behaviour of reinforced concrete structures. The main objective of this study is to establish a rational constitutive model for concrete subjected to monotonic or cyclic loadings and to analyze nonlinear behaviour of reinforced concrete structures by finite element method.</p> <p>The constitutive model described here is built within the framework of rate-independent theory of plasticity. In the present study, the emphasis is placed on an adequate modelling of basic trends in the behaviour of concrete, e.g. compaction-dilatancy transition, sensitivity of material characteristics to confirming pressure, gradual transition in failure mechanisms from a brittle to a ductile mode and phenomenon of cyclic degradation of material stiffness and strength, etc. The proposed model is suitable for describing strain hardening and softening response of concrete under any complex state of stress. In order to describe rigorously the strain softening response, an appropriate criterion for strain localization is derived from considerations of stability of the constitutive relations. The model is verified for a number of loading paths by comparing the numerical results with the experimental data available in the literature.</p> <p>The finite element modelling of reinforced concrete slabs is also presented. In this finite element model, the post-cracking behaviour of concrete and tension stiffening effect are modelling using the proposed constitutive theory. Moreover, some common problems relared to numerical instability are carefully studied. The nummerical results are compared with the experimental data and the results obtained from other analytical models.</p>