Design for Vertical Load on Horizontal Connections in Large Panel Structures

Abstract

T Ire essential difference between a cast-in-place concrete structure and a precast large panel structure is the nature of connections between elements. Connections serve to transfer forces between elements. The ability of large panel structures to perform satisfactorily under all loading conditions depends on the integrity of the connections. Connections must transmit gravity loads from floor to wall elements, from wall to wall elements, and from wall elements to the foundation. If connections are inadequate, the design strength of the adjoining elements may not be fully utilized. However, the design strength of walls may be considerably greater than the required strength. Connections are classified' with respect to location, direction, and funetion. They may be interior or exterior, horizontal or vertical, and wall-to-wall or wall-to-floor connections. A wall-tofloor connection is known also as a horizontal joint or a horizontal connection. The most widely used horizontal connection is the platform connection, also known as the closed or American type connection. The interior American connection as shown in Fig. 1(a) consists of precast top and bottom wall panels, and prestressed concrete hollow-core slabs supported continuously on plastic bearing pads. The space between the ends of floor planks is filled with castin-place grout which may also fill a part of the hollow slab cores. The wall panel above the connection rests on drypacked mortar approximately 1-in. (25 mm) thick, Mortar is packed from both sides of the wall to completely fill the