Browsing by Author "Wang, Xiping"

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Advancing Technology to Manufacture Trusses From Hardwood Lumber
(University of Minnesota Duluth, 2001-09) Brashaw, Brian K; Vatalaro, Robert J; Lackore, Michael; Ross, Robert J; Wang, Xiping; Forsman, John
Low-grade hardwood lumber is abundant across the Lake States and the Northeast United States. This product has historically been used as pallet lumber, crating material, and firewood with values of $200-$300 per thousand board feet. Further, several low-valued hardwood species have become prevalent in these areas through past forestry practices. In order to actively manage the forests for historical species, new and higher value markets must be established. The purpose of this project was to evaluate the use of sugar maple (Acer saccharum) and red maple (Acer rubrum) as structural lumber in metal plate pitched and parallel chord trusses. Groups of trusses were manufactured with both chords and webs from hardwood lumber, from softwood chords and hardwood webs and from chords and webs from softwood lumber. Testing was completed according to ANSl/fPI 2-1995, Standard for Testing Metal Plate Connected Wood Trusses. Results showed that both pitched and parallel chord trusses manufactured from hardwood lumber had strength and stiffness that was equivalent to or better than softwood trusses manufactured from spruce-pine-fir (SPF) and southern yellow pine (SYP) lumber. Trusses manufactured with SPF chords and hardwood webs had properties that were equivalent to or better than complete SPF trusses. The findings indicate that the potential use of low-grade hardwood lumber as truss lumber would result in large volumes of this material being utilized in a higher value application.
Condition Assessment of Main Structural members of the U.S. Brig Niagara
(University of Minnesota Duluth, 2006-12) Wang, Xiping; Wacker, James P
The US Brig Niagara in Erie, Pennsylvania is a reconstruction of an early 19th century wooden warship of the United States Navy. One of six warships built to regain control of the upper Great Lakes from the British during the War of 1812, the hastily built Magara was Commodore Oliver Hazard Perry's relief flagship in the Battle of Lake Erie on September 1051813. In the battle, the entire British squadron of six warships was captured by Perry's nine ship squadron. This pivotal event in the war of 1812 secured the Northwest Territory, opened supply lines, and lifted the nation's moral. After the war, Niagara served as a station ship in Erie until she was scuttled in Presque Isle Bay in 1820. The wreck was raised and rebuilt in 1913 to commemorate the centennial of the battle and became part of the Erie Maritime Museum. Niagara was rebuilt again between 1933 and 1943 and placed ashore in downtown Erie. She underwent her third reconstruction, between 1988 and 1990, which enabled her to return to the water as an active Sailing ship. The testing results show no sign of decay on any of the cant frames and the knighthead tested. However, because the micro-drilling testing was very limited in the forepeak area, we can not conclude that all parts of the cant frames and the knighthead are free from decay.
Condition Assessment of the Masts of Highlander Sea
(University of Minnesota Duluth, 2006-11) Wang, Xiping; Wacker, James P
The Highlander is a 154 ft Grand Bank Topsail Schooner with a round wine glass bottom and full keel, overhanging transom design and Carvel wood planked construction. She was built in 1924 at the Yard of James and Tarr Shipwrights of Essex, Massachusetts. The vessel’s design was created by Starling and Burgess. The Highlander sails with a fixed core complement of Master, Mate, Botswain and Cook and a sailing complement of cadets.
Demonstration of Hardwood Trusses in Residential Construction Projects
(University of Minnesota Duluth, 2002-01) Brashaw, Brian K; Vatalaro, Robert J; Ross, Robert J; Wang, Xiping
The hardwood lumber industry is a key component of the forest products industry in the Lake States and Northeast regions of the United States. Two of the primary lumber species include sugar maple (Acer saccharum) and red maple (Acer rubrum). High grade lumber from these species has an extremely high value, often exceeding $1,500/thousand board feet (M bdft). Lower grades of maple including pallet lumber usually sell for $200 to $275/M bdft. A cooperative Lake States research team developed the technical and economic background necessary for using low grade maple as structural components in metal-plate trusses and prefabricated wood I-joists. Specific projects that have been completed addressed the following research topics: lumber yield and recovery, lumber properties, acce\erated drying schedules, truss plate fasteners, truss fabrication and testing, I-joist fabrication and testing, and :financial assessments. An important step prior to implementation was the development of several demonstration projects using structurally graded maple lumber. A relationship was established with the Duluth Chapter of Habitat for Humanity International and a demonstration project was developed to use the red maple lumber in trusses for two houses with attached garag~s that were to be built during the summer of 2001. To minimize concerns oflumber length and s_pecies, we chose to use red maple as truss webs with spruce-pine-fir (SPF) chords in the house section and red maple for both the truss chords and webs in the attached garage. Red maple cants were obtained, sawn into 2- by 4-in. dimension lumber and dried using an accelerated kiln schedule. Structural grading was completed using an E-computer with visual overrides for #2 a11d #3 grade lumber. Truss designs were completed and sealed by a professional engineer and the trusses were manufactured by Kylmala Truss in Duluth, Minnesota. Natural Resources Research Institute (NRRI) personnel were involved in the setting of the trusses. There were no specific problems noted from the use of red maple in either the house or garage trusses. A second demonstration project was designed to use sugar maple lumber as web stock in a standard storage truss in a garage built in rural Duluth, Minnesota. Kiln-dried hard maple remaining from earlier projects was graded using a commercial E-computer. The lumber was then provided to Kylmala Truss for use in manufacturing a 6:12 pitch garage truss that spanned 26 ft. The trusses were set by NRRI personnel and covered with oriented strandboard (OSB) sheathing. There were no specific problems or challenges identified from using hard maple in the trusses, although it was difficult to hand nail siding to the hard maple web on the gable end trusses.
Development of Flexural Vibration Inspection Techniques to Rapidly Assess the Structural Health of Rural Bridge Systems
(University of Minnesota Center for Transportation Studies, 2008-09) Brashaw, Brian K.; Vatalaro, Robert; Wang, Xiping; Sarvela, Kevin; Wacker, James P.
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 bridges. Each bridge was also inspected using commercially available advanced inspection equipment to identify any major structural problems with individual bridge components such as timber pilings, pile caps, and girders. Two bridges were identified that needed immediate maintenance attention. The relationship between the load deflection data and the vibration characteristics showed a useful relationship and the results indicate that forced-vibration methods have potential for quickly assessing timber bridge superstructure stiffness. However, improvements must be made to the measurement system to correctly identify the 1st bending mode frequency of the field bridges. This global vibration technique has potential benefits for routine inspections and long-term health monitoring of timber bridge superstructures.
Development of Flexural Vibration Inspection Techniques to Rapidly Assess the Structural Health of Rural Bridge Systems: Phase II
(Minnesota Department of Transportation, 2009-12) Brashaw, Brian K.; Vatalaro, Robert J.; Wang, Xiping; Verreaux, Matthew; Sarvela, Kevin
Current timber bridge inspection procedures used in Minnesota and across the United States are mostly limited to visual inspection of the wood components. Use of advanced techniques like stress wave timing, moisture meters, resistance drills will significantly improve the reliability of the inspections but these inspection techniques are time consuming. The objective of this project was to conduct vibration testing of dowel laminated timber bridge systems to better understand the potential for using vibration testing to assess the structural health and condition of bridges in Minnesota. A second key objective was to improve and automate the vibration testing system that is currently being used. This research showed that the forced vibration system developed is an effective tool for conducting forced vibration tests of timber bridges and that there is a noted increase in frequency during each successive stage of construction. A reliable means for assessing the peak frequencies and an identification of the mode still needs to be developed for this system to use the vibration response to predict the EI product for use in load ratings. Each bridge has a unique set of vibration characteristics that were identified using the automated system. These characteristics showed peaks in amplitude as the frequency of the vibration was increased from 0 - 35 Hz during testing. It is believed that monitoring of the characteristic vibration response for each bridge would be a means of identifying changes in structural health over time due to wood decay, accidents, vandalism, or lack of maintenance.
Effect of Freezing Temperature on Stress Wave Speed of Green Ponderosa Pine Boards
(University of Minnesota Duluth, 2003-06) Wang, Xiping; Ross, Robert J
The purpose of this pilot study was to investigate the effect of freezing temperature on stress wave measures of green ponderosa pine boards and to quantify the relationship between stress wave speeds of green boards measured at room temperature and freezing temperature. This study was conducted under a service agreement between the Natural Resources Research Institute (NRRI) at the University of Minnesota Duluth and CHH Fibre-Gen Inc.
Evaluation of the Use of Acoustic Technology to Identify Low Value Logs
(University of Minnesota Duluth, 2007-06) Wang, Xiping; Ross, Robert J; Brashaw, Brian K; Vatalaro, Robert J; Johnson, Scott
The purpose of this service was to evaluate the feasibility and effectiveness of a resonance based acoustic technique for sorting low grade and low value logs from the chip wood mix stems. This work is conducted under a service agreement between the Natural Resources Research Institute (NRRI) at the University of Minnesota Duluth and the Seneca Sawmill Co. in Eugene, Oregon.
Heat Sterilization Times of Five Hardwood Species: Stress Wave E-Rating of Specimens
(University of Minnesota Duluth, 2004-09) Wang, Xiping; Forsman, John W; Erickson, John R
Heat Sterilization of lumber, timbers and pallets is currently used to kill insects to prevent their transfer between countries in international trade. A typical requirement is that the center of any wood configuration be held at 133 °F (56 °C) for 30 min. However, the time required for the center to reach this temperature can vary widely depending on a number of factors such as wood species, physical prope1iies, cross-sectional dimensions, and heating medium, etc. The overall objective of this project was to quantify the effects of wood species, cross-sectional dimension, and heating medium on the time required to heat the center of hardwood lumber and timbers to 133 °Fat a heating temperature of 160 °F (71 °C). A stress wave E-rating procedure was also added to examine if the stress wave properties of lumber and timbers can be any useful in predicting heating times for untested species in the future.
Low Frequency Vibration Approach to Assess the Performance of Wood Structural Systems
(University of Minnesota Duluth, 2003-10) Wang, Xiping; Ross, Robert J; Erickson, John R; Forsman, John W
The primary means of inspecting buildings and other structures is to evaluate each structural member individually. This is a time consuming process that is expensive, particularly if sheathing or other covering materials must be removed to access the structural members. This report presents an effort to use a low frequency vibration method for assessing the structural performance of wood floor systems.
Stress Wave Sorting of Red Maple Logs for Structural Quality
(University of Minnesota Duluth, 2001-11) Brashaw, Brian K; Wang, Xiping; Vatalaro, Robert J
Existing log grading procedures in the United States make only visual assessments of log quality. These procedures do not incorporate estimates of the modulus of elasticity (MOE) oflogs. It is questionable whether the visual grading procedures currently used for logs adequately assess the potential quality of structural products manufactured from them, especially those in which MOE is of primary concern. The purpose of this study was to investigate the use of stress wave nondestructive evaluation (NDE) techniques to sort red maple logs for the potential quality of lumber obtained from them. Twenty red maple logs were nondestructively evaluated using longitudinal stress wave techniques and sorted into four stress wave grades. The logs were then sawn into lumber. Finally, the lumber specimens were dried and graded a final time using longitudinal stress wave techniques. The results of this study showed that good relationships existed between stress wave times measured in logs and the lumber produced from the logs. It was found that log stress wave grades have a positive relationship with the lumber grades. Logs with high stress wave grades produced high grade lumber. These findings indicate that the longitudinal stress wave technique could be used in sawmills to sort logs/cants for the production of high MOE products.

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