PROBABILITY-BASED LRFD FOR ENGINEERED WOOD CONSTRUCTION

The newly developed load and resistance factor design (LRFD) specifica tion for engineered wood construction in the United States uses probab ilistic methods as the technical basis for selecting design strength r equirements, load combinations and load factors. Special characteristi cs of wood and wood products as structural materials are considered. T he strength of wood structural products depends on the rate of applica tion and duration of the loads. LRFD criteria for the ultimate limit s tates account for this dependence by means of a time effect factor. Th e apparent increase in strength of wood structural systems comprised o f several nominally identical and repetitively used members is taken i nto account with a system factor. Serviceability limit states of defle ction and vibration are addressed with some general code guidelines an d a nonmandatory commentary. (C) 1997 Elsevier Science Ltd.