PREFABRICATED MONOLITHIC SLAB WITH CELLULAR CONCRETE SLABS UNDER VERTICAL LOAD ACTION

The paper presents the results of testing by standard distributed loading of two full-scale fragments of precast monolithic slab (PMS). Each fragment was a cell of PMS, including precast autoclaved aerated concrete slabs,installed in a dense group and enclosed in a closed monolithic reinforced concrete frame. The PMS fragments are supported by the ends of the slabs on continuous linear supports that emulate the bearing walls of the building. At the sides,the fragments are supported on point supports by the frame. The paper considers the new data on the nature of the PMS operation and distribution of forces and deformations in its elements under load. A group of plates in each cell of the PMS works under load as a solid plate, freely supported along the contour on the girdles of the framing frame. The moments occurring in this slab under load along the slabs are absorbed by their working reinforcement, while the moment across the slabs causes a transverse strut in the slab plane below. The close contact between the ends of the slab and the cross members of the frame creates a longitudinal brace in addition to the transverse brace. The action of the transverse and longitudinal reactive struts largely cancels out the forces in the slab cross-sections from the action of the load applied to the PMS, which is confirmed by the results of comparative tests of freely supported twin slabs given in the paper. The experiments also showed that these gaps are supported by the chords of the frame flanking the PMS cell. The failure of both fragments was caused by the failure of the sections at the corners of the frame edge with the failure of their longitudinal reinforcement or its yielding. This was followed by sliding of the precast slabs and failure of their sections.