PROPOSED METHOD FOR THE PREDICTION OF LATERAL RESTRAINT FORCES IN METAL BUILDING ROOF SYSTEMS

摘要

The flexural design provisions in Section C3.1 of the North American Specification for the Design of Cold-Formed Steel Members (2001) are based on the flexural member undergoing fully constrained bending with no torsional stresses. Therefore, the capacity of purlin roof systems is dependant on the ability of the roof system to properly restrain the purlins and minimize the torsion in the member. Typical metal building roof sheathing will provide partial torsional and lateral restraint to the purlin. The torsional moments are generally resolved internally within the roof deck and do not require special consideration, but the lateral forces will accumulate across the roof diaphragm and must be removed by external anchorage devices.