Strength Requirements for Shear Diaphragms Used for Stability Bracing of Steel Beams

Abstract

Light-gauge metal sheeting is often used in steel building and bridge industries as concrete deck formwork. Besides providing support to the fresh concrete, the sheeting acts as a shear diaphragm and provides continuous lateral bracing to the top flanges of the beams to which they are attached. An adequate stability-bracing system must possess sufficient stiffness and strength to control deformations and brace forces. Strength requirements for shear diaphragms are currently not well established. A computational study was conducted to develop strength requirements for shear diaphragms bracing simply supported steel beams. Both end-fastener and sidelap-fastener connections were modeled in the study. To the best of the authors’ knowledge, this is the first study to quantify the stability-induced forces in sidelap fasteners. The effects of deck width and number of end and sidelap fasteners on brace forces were investigated. Expressions were developed to estimate the stability-induced brace forces in end-fastener and sidelap-fastener connections.