Z‐Section Girts Under Negative Loading

As part of a wall system in low‐rise industrial buildings, cold‐formed Z‐section girts are attached along one side to cold‐formed steel panels and are often supported along their span by sag rods. Thus, some degree otrestraint is present against the lateral and rotational displacement of these girts. The use of sag rods as a bracing device is often rejected in design on the assumption that the wall panels, once erected, provide adequate lateral restraint to the girts. However, if the wall system is under negative pressure, the Z‐sections are attached to the wall panels along the tension flange. In this case, the bracing contribution of the wall panels is also neglected in the design calculations. Results from a theoretical and experimental program showed that the omission of the restraint contribution of sag rods and steel panels leads to overconservative designs.