Rotational Stiffness of Wood Truss Joints in Lateral and Diagonal Bracing and Truss–Wall Connections

Abstract

The modeling and structural analysis of roof systems composed of metal plate–connected wood trusses (MPCWTs) require a detailed understanding of the rotational stiffness associated with various connections of the MPCWTs to the bracing elements and to the walls supporting the roof. The purpose of this study was to measure the rotational stiffness of several truss–bracing and truss–wall connections attached to MPCWTs to be used for structural modeling. Bracing included discrete and continuous bracing supporting the top and bottom chords of trusses. Truss–wall connections used single fasteners and proprietary sheet-metal connections. For the bracing connections, the rotational stiffness of the discrete bracing was greater than the rotational stiffness of the continuous bracing. Joist hanger–style truss–wall connections had greater rotational stiffness compared with hurricane ties or single-fastener connections. The rotational stiffness of hurricane ties was much greater when the applied torque caused a tension force in the hurricane tie versus a compression force. The rotational stiffness of hurricane ties from two different manufacturers was not significantly different.