ABSTRACT
The stability of precast concrete buildings is achieved in one of two ways. First, the horizontal loads due to wind are transmitted to shear walls or moment-resisting frames by the floor (and/or the roof) acting as a horizontal ‘deep beam', or some other appropriate model, known as a floor diaphragm (because of its depth to floor area being small). The diaphragm must be checked in both orthogonal directions because the complementary shear stresses perpendicular to the direction of loading may be equally as important as those in the direction of the load. Various structural models can be applied to model the shear transfer mechanism between the diaphragm and the bracing elements. The behaviour of a precast hollow-core floor diaphragm is different from that of a solid slab because the precast unit has large in-plane stiffness relative to that of the joints.
