OVERLOAD BEHAVIOR OF SHEATHED LUMBER SYSTEMS

Computer simulation was used to study the overload behavior of sheathe d lumber systems. Simulations included in this study covered two-way a ction of the sheathing; partial composite action between the sheathing , connectors, and lumber members; the random mechanical properties of the lumber members; and the random postyield properties of the partial composite members. A trilinear spring model and a member-replacement technique were introduced to account for the nonlinear behavior of par tial composite members. The primary factors affecting system overload behavior are the variation in the modulus of rupture of the lumber mem bers and the three parameters that describe the postyield properties o f the partial composite members. System-failure criteria are developed and are related to the same factors. A distinction is made between br ittle-member systems and nonbrittle-member systems. The results apply for uniformly distributed loads applied to the system and do not inclu de the effects of load duration.