Numerical modelling of contact element for concrete-to-concrete bond

Abstract

Interface shear strength is an essential requirement to ensure composite action of a composite slab. In order to achieve full composite action, the shear strength at the interface must be strong enough to resist horizontal shear which totally depends on bond and shear of the contacted surfaces. The horizontal shear must be effectively transferred through the interface of the elements. This research is aimed to investigate the shear strength at interface of existing concrete with new layer of concrete topping by use of numerical analysis. The importance of such knowledge is enhanced by the fact that precast slab is mostly preferable in construction of floor and roof system because of the economical use of the concrete and its light weight properties. In this study, two contact elements namely Rigid Body and Slide Line are used to model concrete-to-concrete bond of existing concrete and new layer of concrete topping. To this regard, the proposed material modelsare integrated into finite element software through a basis of experimental data from small scale push-off test. The main consideration include in model are details of the structural components, contact condition between existing concrete and new layer of concrete topping, associated boundary conditions and loading. The load-slip relationship of finite element analysis result is then verified with the experimental test. From the finite element analysis result, the Slide Line contact element shows good agreement with experimental result with 20.12% difference compare to 28.41% by Rigid Body contact element.