Nonlinear Modeling of Truss‐Plate Joints

Abstract

A theoretical model is developed for predicting mechanisms of load transfer between a wood member and a metal die‐punched truss plate. The model, which treats a truss‐plate tooth as a beam on an inelastic foundation of wood and applies Runge‐Kutta numerical analysis to solve the governing differential equations, predicts the load‐displacement trace and ultimate load of truss‐plate joints. The model is verified with eight truss‐plate joint types, three of which varied the number of teeth and five the plate and grain angle. Theoretical and experimental load‐displacement traces show good agreement. Experimental traces show no significant difference between multiple teeth in rows and columns, indicating little stress interaction among teeth. The theoretical model accurately predicts the ultimate load and failure modes for complete joint test types, which vary with plate and grain geometry; teeth face bearing on end grain failed by tooth withdrawal or plate tensile failure, teeth edge bearing on end grain failed by plate peelback, and teeth bearing on side grain failed in wood perpendicular to grain.