End-colloquium Lucas van Bemmelen

Failure Behavior of Cast-In Lattice Girder Connections in Composite Concrete Floors

In 2017, the parking garage of the Eindhoven Airport collapsed. It consisted of composite concrete floors placed in such a layout that the floors had to transfer a positive moment between plates. The collapse launched widespread research into the structural reliability of these floors. Special attention was brought to the so-called critical detail: a detail in the floors where a positive moment has to transfer from one plate to the other plate through the in-situ layer. Three main failure modes were determined: yielding of the reinforcement, failure of the interface between the two concrete layers, and lattice girder pull-out failure. 

Previous research focused on these failure modes. However, a potential for research is still present on the subject of lattice girder failure. Experimental research was conducted on the lattice girder pull-out in tension and numerical research on the failure in a full-floor FE model. Detailed knowledge about the behavior in combined loading, as is the case in composite concrete floors, is still absent and unclear. The relation between the embedment depth of the lattice girder and the exact resistance of the anchorage point is investigated. 

This research focuses on the failure behavior of lattice girders connections under combined loading consisting of a tension force, shear force, and a moment. This resembles situations often occurring inside composite concrete floors when applied near a mid-span joint containing a critical detail. An experimental setup is created to test the lattice girders in-situ anchorage when subjected to the combination of these forces.