Stiffness of screw-fastened, metal-clad, timber-framed roof diaphragms with openings in the sheeting.

ABSTRACT Fifteen nominal 2.34 m x 3.66 m (7-2/3 ft x 12 ft) diaphragms were constructed, tested, and analyzed with a plane truss analog. The analog predicted the diaphragm stiffness within approximately 10% of test values. Four of the diaphragms had 33% and six had about 11% of the sheeting removed. Those with 33% of the sheeting removed were ineffective as diaphragms; whereas, the stiffness of the diaphragms with 11% of the sheeting removed was more dependent on the type and location of the fasteners. Three of the diaphragms had the purlins recessed, which resulted in a small decrease in stiffness. The general behavior of the diaphragms is discussed.