Experimental Investigation of the Diaphragm Behavior of a New Deep Steel Deck Profile with Flange and Web Stiffeners

Abstract

In North America, steel deck diaphragms are commonly used in low-rise commercial and industrial buildings as a roofing system to resist gravity loads. They are also used to transfer the in-plane shear forces generated by wind and seismic loads to the lateral force-resisting systems. A new 100 mm deep steel deck profile with longitudinal web and flange stiffeners, the MS100 profile, is being developed by Metal Sartigan Inc., Polytechnique Montreal, and Université de Sherbrooke. This type of deep stiffened steel deck is produced for the first time in Canada. This article describes a series of five large-scale monotonic quasi-static diaphragm test programs that was conducted on the new deep deck profile. Power-actuated fasteners were used for structural connections where self-drilling screws were used for side-lap connections. In each test, the diaphragm shear strength and stiffness were measured together with the global ductility. The measured strength and stiffness values are compared to AISI S310-20 and AISI S310-16 predictions. The results showed that MS100 steel deck diaphragms can exhibit sufficient strength for typical building applications. In the tests, it was observed that the shear strength was controlled by local buckling of the deck webs at the exterior support when closely spaced connections were used. For these specimens, the AISI S310-20 calculation method could predict reasonably well the shear strength, compared to AISI S310-16, even if the method does not account for the presence of web stiffeners. As expected, the measured diaphragm shear stiffness of such a deep deck profile is relatively low. The ductility of the tested diaphragms as measured under monotonic quasi-static loading varies from 6.95 to 11.2.