Creep Effect in Structural Composite Lumber for Bridge Applications
Publication: Journal of Bridge Engineering
Volume 9, Issue 1
Abstract
Structural composite lumber (SCL) is a family of newly engineered wood products that are increasing in highway bridge applications. Advantages of SCL are its high strength, flexibility, stiffness, and excellent preservative treatability. A main concern in SCL bridge applications is serviceability performance. The long-term creep behavior of SCL flexural members is not presently determinable. In order to investigate creep effects, deflection monitoring of full-scale SCL T-beam bridge members was performed under ambient conditions and an accelerated aging process. Sixteen beams were monitored under exposed weather conditions with frequent wetting and drying. Variables in the experiment were: lumber type (Douglas fir and southern yellow pine), SCL type (LVL and PSL), preservative type (CCA and penta), and dead load intensity. It was found that creep behavior in SCL bridge members closely follows the Burger theoretical model. LVL, Douglas fir, and CCA treatment causes smaller creep deflections as compared to PSL, Southern Pine, and Penta treatment. NDS type creep multipliers for SCL vary between 2.2 and 2.67 for various subcategories. A single average creep multiplier of 2.3 may be used for treated SCL bridge beams.
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Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 9 • Issue 1 • January 2004
Pages: 87 - 94
Copyright
Copyright © 2004 American Society of Civil Engineers.
History
Received: May 3, 2002
Accepted: Dec 17, 2002
Published online: Dec 15, 2003
Published in print: Jan 2004
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