Behavior of Stress‐Laminated Timber Highway Bridge

Abstract

This paper recounts an examination of longitudinal stress‐laminated timber deck bridges as a solution to the tremendous need for replacement bridges, particularly on rural roads. A long‐span full‐scale deck was built in the laboratory and subjected to a series of tests and theoretical analyses to obtain behavioral information. The stress‐laminating procedure was found to be an effective means of developing a wide “distribution width” for resisting loads on a longitudinal deck bridge. The laboratory study was followed by construction of a prototype bridge in the United States and development of a method for assembling a bridge deck from prefabricated stressed panels. In addition to having a wide distribution width, the stress‐laminated deck was found to provide a medium range bridge span with a thin section allowing sufficient hydraulic clearance, to be able to built with a simple anchorage system for prestressing rods, to provide an economic bridge system compared with steel and concrete, and to be quickly and easily erected. The primary limitation in use of the system is in the span range which can be attempted without exceeding deflection limits.