Treesearch

Our society depends on wood for a variety of uses. As population increases, so does our need for wood. Steel, concrete and aluminum are some alternatives to treated wood in certain applications, but they have higher material costs, higher energy requirements in the production process, greater air and water pollution or environmental protection costs, and greater dependency on foreign sources for materials. Substitute materials may not be appropriate for some uses. For example, some types of steel may corrode; concrete may deteriorate in salt water; and plastic may not have the necessary...

Approximately 4,000 vehicle bridges in the State of Minnesota contain structural timber members. Recent research at the University of Minnesota Duluth Natural Resources Research Institute (UMD NRRI) has been conducted on vibration testing of timber bridges as a means of developing rapid in-place testing techniques for assessing the structural health of bridges. The technique involves measuring the frequency characteristics of the bridge superstructure under forced flexural vibration. The peak frequency of vibration was measured and compared to a set of load testing data for each of 9...

The participants to the workshop were given the charge to discuss (1) bridge design issues including best practices in design and detailing that could be used to improve durability, extend service life and prevent premature deterioration, (2) performance measures needed to better determine bridge condition, (3) technologies that could be used to monitor bridge life and assess condition, and (4) improving decision-making through comprehensive collection and evaluation of bridge performance and operations data and other topics which the groups felt were of importance.

Transverse vibration as a nondestructive testing and evaluation technique was first examined in the early 1960s. Initial research and development efforts focused on clear wood, lumber, and laminated products. Out of those efforts, tools were developed that are used today to assess lumber properties. Recently, use of this technique has been investigated for evaluating a range of wood materials--from logs to wood-based structural systems. This paper presents the technique and its use to evaluate a variety of wood-based materials and systems.

Technology transfer is often an afterthought for many nondestructive evaluation (NDE) researchers. Effective technology transfer should be considered during the planning and execution of research projects. This paper outlines strategies for using technology transfer in NDE research and presents a wide variety of technology transfer methods used by a cooperative research team from the University of Minnesota Duluth, the USDA Forest Products Laboratory, and other public and private cooperators.

A preliminary study to determine possible treatments that might be used to eliminate or limit value reducing stain in soft maple suggests that rapid processing and treatment with sulfur dioxide gas decreases discoloration, high-temperature drying increases discoloration, and freezing in dry ice prior to processing has no effect.

Impedance spectra were collected from Southern pine (Pinus spp.) equilibrated to a moisture content 20% and a saturated condition. Cylindrical graphite electrodes were embedded in the wood so that they met nearly end-to-end along a line parallel to the grain, and impedance properties were characterized as functions of electrode spacing and electrode contact pressure at frequencies between 1=10-1 and 3=105 Hz. The data exhibit a low-frequency tail that can be fit with a Warburg element, indicative of a diffusive motion of charge carriers. Values of the Warburg impedance were compared with...

This paper summarizes the field condition assessment of three historically significant wood vessels. The vessel WAPAMA, built in 1915, is the last surviving example of the wood steam-powered schooners designed for the 19th and 20th century Pacific Coast lumber trade and coastal service. The U.S. Brig NIAGARA is a wood war­ship of the U.S. Navy that played a pivotal role in the War of 1812 in the Battle of Lake Erie. The HIGHLANDER SEA is Grand Bank Topsail Schooner built in 1924 for use on the Great Lakes and Eastern Seaboard. A variety of state-of-the-art nondestructive testing technologie...

Over the last several decades, oriented strandboard (OSB) and similar composite materials (flakeboard) have been successfully used to sheath residential, and to some extent, commercial structures. However, when used as exterior siding, they have often failed, often even if they were painted. The performance of OSB and flakeboard has not been consistent when used outdoors. Little is known of how manufacturing parameters, such as the amount of adhesive (resin), water repellent (wax and similar products), pressing conditions, and other factors, such as geographic area and paint, affect...

On Wednesday, September 13, 2006 through Friday, September 15, 2006, forestry scientists from Michigan Technological University and their cooperators conducted decay detection tests on 10 red pines supporting a ropes course in the United States Forest Service (USFS) Nesbit Lake Camp in Sidnaw, Michigan. The Copper County Intermediate School District (CCISD), Hancock, Michigan, cooperated with the USFS in providing the recreational ropes course for use by students and other groups. The purpose of the project, in addition to detecting decay, was to research the reliability of detection...