An experimental and theoretical investigation of the shear strength of reinforced concrete slabs without shear reinforcement is under way at the Ecole Polytechnique Fédérale de Lausanne. The first part of the program consists of 6 tests on two large scale bridge deck cantilevers. The specimens are tested under different configurations of concentrated forces simulating traffic loads. The observed failure mode is shear. The second part of the experimental program consists of shear tests on 12 slab strips, to investigate the influence of plastic hinge rotation on the shear strength. The test results show that the shear strength decreases with increasing plastic hinge rotation.