Lattice Girder Elements in Bending: Pilot Experiment.

A test was conducted on two Lattice Girder Elements in order to evaluate the mechanical behaviour in bending. Lattice Girder Elements are used as permanent formwork in in-situ concrete construction. However, the present design method for the elements is based on empirical expressions and is believed to be over conservative and, most important, not sufficient to describe the mechanical behaviour. In the conducted test it was found that the peak-load was limited by buckling of the top chord in the lattice girder. Furthermore, cracking of the concrete started at a low load level (typical at 20 percent of the peak-load). However, the crack widths were small even at the peak-load. The suggested analytical method seems to be able to predict the behaviour rather well but the study indicates some parameters that are crucial and which need to be investigated further