Reports

Our newest report published in August 2003 is entitled "Behavior of Traditional Timber Frame Structures Subjected to Lateral Load" by Robert G. Erikson and Richard J. Schmidt of the University of Wyoming. The research was sponsored by the University of Wyoming and the Timber Frame Business Council.

Abstract

Timber framing is a method of construction in which heavy timber members are connected with carpenter-style joinery and wood pegs. Timber frames are commonly enclosed with structural insulated panels (SIPs). Current building codes do not provide guidelines for wood structures with wood pegged connections. The intent of this research was to provide a basis for implementing provisions for this type of structure in building codes.

Specifically, this project investigated the effects of lateral load on the stiffness of full-scale timber frames. The frames were tested in both the unsheathed and sheathed condition and weremodeled with a structural analysis program. Load-slip characteristics for single-fastener SIP-to-timber connections were developed. Excessive displacements of the frames indicated unacceptable flexibility when subjected to reversible lateral loads. This lack of stiffness was due to the inefficiency of knee braces for resisting lateral load. However, the knee brace system provided exceptional strength characteristics due to the substantial available compressive action of the joints. The addition of SIP sheathing significantly improved frame stiffness.

In order to accurately model the displacement characteristics of a frame, we included the characteristics of the pegged connections in the model. For sheathed frame models, the implementation of nonlinear SIP-to-timber connection elements produced accurate predictions of sheathed frame stiffness.