STEEL-DECK-REINFORCED CONCRETE DIAPHRAGMS .1

Steel-framed buildings are typically constructed using steel-deck-rein forced concrete floor slabs. The in-plane, or diaphragm, strength and stiffness of the floor system are frequently utilized in the lateral-l oad-resisting system design. However, design provisions for composite diaphragms do not exist in any U.S. specification, and limited experim ental data are available to assess the behavior of these systems. This paper presents the results of an experimental research program in whi ch 32 full-size composite diaphragms were loaded to failure. Partial r esults from a large series of elemental tests performed in conjunction with the full-size tests are also presented. Typical composite diaphr agm limit states are described, and the controlling limit state for ea ch of the full-size tests is indicated. The results presented in this paper provide background for a companion paper, in which the developme nt of an analytical procedure to determine the strength and stiffness of the experimental composite diaphragms is presented. The procedure i s based, in part, on results of finite-element modeling of the experim ental diaphragms. A description of the models and the results are also given in the companion paper.