MODELING THE INTERFACIAL TRANSITION ZONE BETWEEN STEEL AND CONCRETE MATERIALS IN COMPOSITE CONSTRUCTIONS

Abstract

The interfacial Transition Zone (ITZ) has long been recognized as the “weak link” in a structure. While steel materials behave relatively linear up to high stress levels, nonlinearity is a prominent characteristic of most cementitious based material. To obtain a more realistic representation to the overall behavior of composite steel-to-concrete structures, the response of the interface should be incorporated into the analysis. A Finite Element Program written in the Visual Basic programming language is developed to take into account nonlinearity of the cementitious materials, while incorporating the Interfacial Transition Zone behavior. The Transition Zone is modeled as two springs, perpendicular to each other. The individual load-deformation responses of the springs were obtained from laboratory tested specimens. The Federal Institute of Technology, Europe Model Code 2011 was used to model the cementitious material behavior. Failure criteria are analyzed based on the principal stresses at Gauss points.