Experimental and Numerical Analysis of Continuously Coupling Timber-Lightweight EPS Concrete Composite System

A composite system based on concrete and timber represents a very successful engineering solution in the process of optimization of construction. Nowadays, by combining different timber products and concrete classes it is easy to achieve improved engineering features for elements in different static systems or load cases. This paper presents an overview of the research initiated by solving the problem of the actual load-bearing capacity of the already built composite timber-EPS systems which based their calculation on the theory of coupling timber with normal concrete. The research was taken at the Faculty of Civil Engineering, the University of Zagreb to define the behavior of timber-Extruded Polystyrene (EPS) lightweight concrete composite system for two different connecting methods, with discrete and continuously distributed connectors. Dowels are used as discrete connectors and vertically positioned steel sheet in combination with built-in reinforcing mesh was used as a continuous connector with significantly proven advantages compared to the discrete dowel type in the case of reverse cycling loads. Shear tests, as well as full-test of the continuous connector, showed the full-composite behavior of the composite system up to the two-third of failure force which also indicates a possible application of the system at the bridge structures as well. Numerical analysis was performed. Numerical models and laboratory measurements show good matching so the model can be taken as a base for further system optimization and design calculations. Critical review and recommendations for further improvement of this coupling method are presented.