Abstract
In this report characteristics on the shear resistance of void-slabs are investigated in some series of tests with regard to the slab strips parallel to the void direction. It is pointed out that the void-ratios, i.e. the hole diameter to the slab depth ratios, influence the unit shear strength and also failure mechanizms. In the case of comparatively large ratios the unit shear strength is considerably enhanced by the combined effects of the I-type section and the web reinforcement by the winding pipes. In the caseof usual middling ratios, showing shear-compression failure mode, the ultimate shear strength takes about 1.5 times as much as the values computed from empirical formula for ordinary rectangular beams. When the hole diameter becomes small, shear-tension failure appears and the strength is almost equal to that of the corresponding rectangular beams. These results are also supported by a study of the data from some previous tests by other investigators. A simple experimental formula to evaluate these effects is presented.
