Reliability‐Based Design of Wood Members Subject to Ponding
Publication: Journal of Structural Engineering
Volume 119, Issue 11
Abstract
Ponding loads coupled with creep effects may contribute significantly to the nonperformance (ultimate failure) of wood roof members. Proposed load and resistance factor design (LRFD) specification provisions for the flexural design of wood beams in roof systems that may be subject to ponding loads include: (1) A check to determine if the member is subject to ponding loads as designed; and (2) a modified design equation to include a ponding moment amplification factor. These equations, however, include largely empirical treatments of creep effects using creep factors taken directly from the previous National Design Specification for Wood Construction. These creep factors were originally developed for use in deflection‐checking equations. This study investigates the effects of creep on the safety of wood roof beams subject to ponding loads. The results of the analysis are used to evaluate a creep factor for design on a more rational basis that includes time effects (i.e., the coupling of creep and moment magnification). Finally, the validity of proposed LRFD specifications is examined and suggestions are made for their modification.
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Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 119 • Issue 11 • November 1993
Pages: 3326 - 3343
Copyright
Copyright © 1993 American Society of Civil Engineers.
History
Received: Jun 24, 1992
Published online: Nov 1, 1993
Published in print: Nov 1993
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