Shear-torsion tests on 400 mm hollow core floor

Fifteen load tests on a floor comprising four prestressed hollow core slabs were carried out to clarify the interaction of shear and torsion. The slabs were 400 mm in depth, 1.2 m in width and 7 m in length. The ends of the slabs were simply supported on concrete beams. The loads in each test comprised one or two concentrated loads close to the support. In twelve tests the loads were limited to a typical service load. In these tests the behaviour of the floor was relatively linear and no sign of failure could be observed. In three tests the floor failed locally. The observed failure loads were 25-97% higher than in a reference test on a single slab unit with identical support conditions. In the first failure test with one point load the failure mode was punching. In other two tests with two point loads, as well as in the reference test with one point load, the failure was a typical shear-torsion failure. As a subtask of HOLCOTORS project, the test results have been used by Chalmers University of Technology for calibration of computerized calculation methods they have developed. This work is published elsewhere. Therefore, the present design practice has not been evaluated here in view of the obtained results.