Tests of Post-Frame Building Diaphragm

Abstract

Diaphragm test results of a full-scale post-frame building are presented. The post-frame building was tested at various stages of construction to determine the contributions of the different components of the building system as metal cladding was added. Subsequently, the effectiveness of different bracing systems (steel bracing, plywood sheathing, and stitching of panel overlap seams) was evaluated for supplemental reinforcement of an end wall that contains an opening equal to 25% or 50% of the area of the end wall. Wind loading was simulated by applying horizontal loads at the eave. Measured eave deflections and applied loads were used to predict stiffness values of interior frames, roof diaphragm, and end walls. Strain gauges were installed on roof purlins in end, middle, and intermediate bays across the building width to determine the interaction between the roof framing system and the metal-cladding membrane. The full-scale tests provided several insights, including (a) in-plane deflection of end walls, (b) continuity between the two roof halves, (c) load sharing between frames, (d) interaction between roof purlins and metal cladding, and (e) contribution of interior purlins in resisting diaphragm forces.