Horizontal Joint Tests. Supplement Report B. Design and Construction of Large-Panel Concrete Structures

摘要

Full - scale tests conducted on horizontal joints to investigate the behavior of wall - to - floor connections are described in this research report, one of three studies on the integrity of large - panel concrete structures. Sixteen full - scale joint tests involved specimens consisting of an assembly of precast hollow - core floor slabs and precast concrete wall elements forming a wall - to - floor connection. The specimens represented a short length of wall from a large - panel building. Grout was used to fill the joint between the ends of the floor slabs. Transmission of vertical load through the joint was examined by applying vertical compressive force in increments. The seven splitting tests were made on specimens consisting of a short wall element loaded to represent partial surface loading present in the joint. Controlled test variables were strength of grout, amount of transverse wall reinforcement, filled or unfilled slab cores, and applied floor moment and rotation. Compressive strength of concrete and precast hollow - core slab elements were kept constant. Patterns of grout crushing, wall splitting, and slab crushing were identified. The tests indicated that joint capacity increases with grout compressive strength, wall splitting does not occur when low - strength grout is used, filling slab cores with grout directly affects joint strength, inadequate dry packing below the upper wall panel leads to loss of joint strength, and floor moment and rotation do not affect joint capacity. Various design methods for determining load capacity of horizontal joints are discussed, comparisons of measured and calculated strength for various joints are made, and details of the experimental program and properties of grouts used are provided, as are detailed recommendations for specific analysis and design of connections. Illustrations and photographs support the study; references are included.