دانلود رایگان مقاله انگلیسی روشی ساده برای مدل خط اتصال بتن- میلگرد فولادی در بتن مسلح - اشپرینگر 2017

Abstract

For correct description of cracking process in reinforced concrete structural elements, the simulation of the behaviour of steel rebarconcrete interface is always of primary importance. This paper proposes a simplified method to model the steel rebar-concrete interface in RC structures. The proposed method considers the introduction of massive elasto-plastic isotropic bond element as steel rebarconcrete interface. Stress-strain behaviour curve required for elasto-plastic isotropic material is obtained by performing conventional pull-out tests on concrete. For plain concrete matrix, an orthotropic damage model based on plasticity and damage theories was adopted for finite element modelling in Finite Element (FE) code CASTEM. In order to validate the proposed approach, a comprehensive experimental program was designed and carried out. Under this program, pure tension test on RC prisms and flexural test on RC beams were performed. Testing of proposed steel rebar-concrete interface bond model in numerical simulation of RC prism subjected to pure tension and RC beam in flexure, and comparison of numerical simulation results with experimental data is also discussed in this paper.

4. Conclusions

A simplified approach to model steel-concrete interface in reinforced concrete structures has been proposed in this contribution. Interface between steel rebar and concrete is modelled using volumic element with elasto-plastic multi-linear hardening behaviour. Stress-strain curve required for interface bond element in RC is obtained from experimental pull-out test results modified by a reduction coefficient of 0.5 to account for the difference in shear stress distribution along the steel bar in pull out test specimen and in other RC elements. The ability of proposed approach to model steel-concrete interface has been illustrated by testing it in simulating behaviour of RC prism subjected to pure tensile loading and RC beam in flexure. Simulation results indicated good agreement with experimental observations. The simplicity of the simulation approach lies in the fact that all model parameters have definite physical meanings and their values may be determined by performing some classical tests on concrete and steel specimens.