Tragverhalten randnaher Betondübel unter Längsschubbeanspruchung

Load bearing behavior of concrete dowels in a location close to a free surface under longitudinal shear stress.

Over the last decades, composite structures made of steel and concrete have been developed in order to allow for the economic and competitive construction of buildings and bridges. Due to the new developments of innovative shear connectors such as concrete dowels, high requirements are expected for the load-bearing capacity and the ductility. The shear connectors are often used in slender structures. Concrete dowel close to a free concrete surface of a slab introduce longitudinal shear forces, which cause failure- relevant splitting stresses in direction of the slab thickness, similar to the horizontal lying headed studs. This failure mechanism of concrete dowels with a low concrete cover perpendicular to the central axis of the shear connectors has not been explicitly considered in the structural design models. First experiments in order to investigate the load-bearing capacity and the ductility of concrete dowels in a location close to a free surface in shear and pull-out tests were carried out. Some relevant parameters that have influence on the load-deformation behavior of concrete dowels located closely to the surface are discussed with reference to the experiments.