First-Order Reliability Analysis of Wood Structural Systems

Abstract

Computer simulation and an approximate method were used to study the lifetime behavior of wood floor and roof systems. A simplified beam-spring model was used to model the systems. In this study, two-way action of the sheathing; partially composite action between the sheathing, connectors, and lumber members; the random mechanical properties of the lumber members; the random postyield properties of the partially composite members; and the cumulative damage of wood were included. The approximate method was the first-order reliability method incorporated with the distributions of order statistics. System reliability analysis, including system effects and load duration effects, is presented in this paper. System factors for load and resistance factor design (LRFD) as they are related to component properties, mostly the postyield properties of partially composite members and variability of lumber modulus of rupture (MOR), are determined. The results herein apply only to uniformly loaded systems simply supported at two edges.