Analysis of Nonlinear Connection Systems in Wood Dwellings

Abstract

Connection systems, such as those joining floor, wall, and foundation, have been long recognized as the weakest structural link in light‐frame wood dwellings. This paper describes a procedure for structural analysis and a computer program, COMPCON, for predicting overall stiffness and strength of such connection systems. The program incorporates the finite element method and a linear step‐by‐step analysis that includes multilinear models for behavior of wood materials, joints, and intercomponent gaps. Model accuracy is verified by comparing predicted results to known solutions for simple systems and to observations obtained in testing nine assemblies that simulate connections among foundation, floor, and wall. Predicted and observed deflections agree closely. Sensitivity studies show that stiffness caused by nailing exterior sheathing to lumber framing affects interactions the most. Connection behavior is highly nonlinear; stiffness generally decreases with the load, but it can also increase when interlayer gaps close.