Treesearch

The Connell Lake bridge was constructed in early 1991 on the Tongass National Forest, Alaska, as a demonstration bridge under the Timber Bridge Initiative. The bridge is a stress-laminated deck structure with an approximate 36-ft length and 18-ft width and is the first known stress-laminated timber bridge constructed in Alaska. Performance of the bridge was monitored for 2-1/2 years, beginning at bridge construction. Performance monitoring involved gathering and evaluating data relative to the moisture content of the wood deck, the force level of the stressing bars, and the deflection...

In this study, we developed a simple equation to calculate average fiber stress values for design of glued-laminated (glulam) timber utility structures as a function of design bending stress. We took design stress in bending values specified by the American Institute of Timber Construction (AITC) for various combinations of glulam timber, applied appropriate end-use adjustments, and determined an appropriate factor to obtain average modulus of rupture. Fiber stresses for glulam were then determined from the average modulus of rupture values using the relationship between these values and...

In bridge applications, it is often necessary to minimize the depth of the bridge structure to provide for the required hydraulic opening or reduce the volume of approach fill. For bridges that utilize structural glued-laminated (glulam) timber beams as stringers, reinforcement using thin strips of pultruded E-glass-fiber-reinforced plastic (GFRP) composites may permit reduced depth, because the reinforcement has the potential to increase stiffness and strength. This study is part of an overall effort aimed at evaluating the potential for commercial production of glulam-GFRP beams in...

The Sanborn Brook bridge was constructed in August 1991, 10 miles northeast of Concord, New Hampshire, as part of the demonstration timber bridge program of the USDA Forest Service. The bridge is a simple-span, double-lane, stress-laminated deck superstructure constructed from Southern Pine lumber and is approximately 25 ft long and 28 ft wide with a skew of 14 degrees. The performance of the bridge was monitored continuously for approximately 2 years, beginning shortly after installation. Performance monitoring involved collecting and evaluating data pertaining to the moisture content of...

The Big Erickas bridge was constructed during September 1992 in Baraga County, Michigan. The bridge is 72 ft long, 16 ft wide, and consists of three simple spans: two stress-laminated deck approach spans and a stress-laminated box center span. The bridge is unique in that it is one of the first known stress-laminated timber bridge applications to use Eastern Hemlock sawn lumber and a combination of stress-laminated decks and a stress-laminated box in a single bridge. Performance of the bridge was monitored for 35 months, beginning at the time of installation. Monitoring involved gathering...

The feasibility of utilizing cant-sawn hardwood lumber, which would not usually be desired for furniture manufacture, was studied for the manufacture of structural glued-laminated (glulam) timber. Two red maple beam combinations were evaluated: (1) a glulam combination designed with E-rated lumber in 25 percent of the outer laminations (top and bottom) and No. 3 grade lumber in 50 percent of the center laminations and (2) a wide-width glulam combination with laminations made from nominal 2- by 4- and 2- by 6-in. No. 2 grade lumber laid edge-to-edge having staggered end joints (termed 2 by...

This report presents a relational database with estimates of annual production capacity for all mill locations in the United States where paper, paperboard, or market pulp were produced from 1970 to 2000. Data for more than 500 separate mill locations are included in the database, with annual capacity data for each year from 1970 to 2000 (more than 17, 000 individual data records). Numeric code, company name, city, state, region, and local postal ZIP code are included in the database. Capacity estimates are given for each of 12 principal categories of paper or paperboard commodities as...

This paper summarizes a cooperative research program between the USDA Forest Service, Forest Products Laboratory (FPL), in Madison, Wisconsin, and Forintek Canada Corp. in Vancouver, British Columbia, Canada. This research program provided detailed creep1rupture and some creep information for composite panel products. Commercially produced plywood, oriented strandboard (OSB), and minimally aligned waferboard were tested to identify nine mills (three for each product) that produced panels with a range of flexural creep performance. The three plywood, three OSB, and three waferboard products...

The Lake States of Michigan, Minnesota, and Wisconsin consist of 49.4 million hectares (122 million acres) of land, 19.8 million hectares (49 million acres) of which are forested, with 6% of those having been removed by law from timber production. Aspen (Populus tremuloides) is an important component of this resource. In recent years, a concern that the aspen cut will exceed its growth has surfaced. That is, Will the aspen supply be adequate to support the growing solid-wood, composite, and paper industries in the Lake States region? To satisfy the increased demand for forest products, it...

Recent research on the release of wood preservatives from treated wood used in sensitive environments has not considered the potential contribution from construction residues. This study sought to develop leaching rate data for small construction debris and compare those to the release rate from treated wood itself. Western hemlock boards were pressure treated with chromated copper arsenate Type C (CCA-C), and then common construction tools were used to generate sawdust or shavings from those boards. These wood particles were then leached in deionized water, and the leaching rate was...