Cyclic Behavior Of Hollow-Core Diaphragm Subassemblies

This paper highlights the results of the experimental phase of a comprehensive research project on the seismic performance of hollow-core diaphragms. The four specimens tested resembled a subdiaphragm region framed by beams. Variations in the boundary conditions of the hollow-core slabs and the inclusion of a cast-inplace concrete topping slab were considered. A bidirectional test fixture was used for simultaneous control of in-plane lateral load and bending deformations. Global and local behaviors were examined under a sequence of increasing cyclic demands. Untopped hollow-core diaphragm specimens exhibited stable behavior that was influenced by shear strength along longitudinal joints and a bearing mechanism that developed between the hollow-core slabs and the supporting beams. The performance of the topped specimen was affected by localized damage to the cast-in-place concrete topping and large demands on the welded-wire mesh reinforcement.