Abstract

In certain cases the concrete slab of wood concrete composite beams can crack; deformations will increase and the internal forces will be redistributed. At present, the design recommendations available vary from ignoring the effect to reducing stiffness by 60%. In order to characterize more correctly the influence of the concrete cracking on the force distribution in wood concrete composite beams a research project was conducted involving theoretical analysis and laboratory tests. First, a parameterized nonlinear FEM model was elaborated and calibrated by real test data available from the literature. Second, shear tests were conducted with test specimens that simulate the concrete cracks by a small separation between the concrete and the timber. The results indicate that the concrete cracking does not only reduce the stiffness of the concrete slab itself but also leads to a significant stiffness reduction of the shear connectors embedded in it.