DAMAGE ACCUMULATION IN WOOD STRUCTURAL MEMBERS UNDER STOCHASTIC LIVE LOADS

Abstract

Damage accumulation in wood structural members was assessed using realistic stochastic modeling of live load. The model indicates that practically all damage occurs when the live load intensity is equal or nearly equal to the nominal live load, L n , a quantity required by codes for design. Currently, basic allowable stresses for wood are calculated assuming a period of 10 years spent at the nominal live load. The model indicates that the time the live load is at or above the nominal is not 10 years but about 40 days in a reference period of 50 years, strongly suggesting that the 10-year period generally assumed for setting allowable stresses is much too long.