Experimental investigations on a novel concrete truss structure with cast iron nodes

Abstract

Truss structures are among the most efficient load-bearing structures in the building industry. Thus, concrete truss structures were already built in the early years of reinforced concrete construction. However, the difficulties associated with their execution prevented the permanent establishment of concrete truss structures. In this context, this article shows a possibility to further exploit the potential of concrete truss structures. A truss structure consisting of concrete struts and cast iron nodes is presented. The components are connected by a grout, whose bond to the cast iron nodes is ensured by shear keys at the inner surface of the nodes. In order to investigate the load-bearing behaviour of this new connection, an experimental program with two types of tests was conducted: tests on grout-cast iron plate assemblies under axial loading and tests on concrete-cast iron pipes assemblies under bending. The evaluation of these test series and the discussion of the results are the focus of this article. As relevant characteristics of the load-bearing behaviour of the connection the bond strength and stiffness were determined. Different failure modes were observed and need to be addressed for the structural design of the connection. All in all, this study indicates that the new type of connection has a good load-bearing behaviour and could encourage the use of concrete truss structures for future applications.