• Structural health monitoring of Klehini River bridge

      Xiao, Feng (2012-08)
      The objective of the research is to improve the safety of bridge structures in the state of Alaska through implementation of innovative structural health monitoring (SHM) technologies. The idea is to evaluate structural integrity and serviceability, and to provide reliable information for changing structural response, etc. of monitored bridges. Based on the finite element model's moving load analysis, modal analysis results and field inspection, this study was used to establish a bridge SHM system for a particular bridge including a preferred sensor layout, system integrator and instrumentation suitable for Alaska's remote locations with harsh weather. A variety of sensors were proposed to measure and monitor structural and environmental conditions to assist in the evaluation of the performance of the Klehini River Bridge. This system is able to provide more reliable information on the real structural health condition. It can be used to improve safe performance of this bridge. As a new safety and management tool, this SHM system will complement traditional bridge inspection methods. Implementation of an effective monitoring system will likely result in a reduction in inspection manpower, early detection of deterioration/damage, development of optimum inspection cycle and repair schedules before deterioration/damage grows to a condition where major repairs are required.
    • Tire chain damage on bridge deck wearing surfaces

      Muench, Wilhelm; Hulsey, J. Leroy; Barnes, David L.; Perkins, Robert A. (2017-12)
      A light weight, durable, and damage-resistant material is needed as a wearing surface replacement for a two-lane bridge deck that is on a 6% grade. The wearing surface to be replaced is 9.2-m wide and is attached to an orthotropic closed cell steel deck that supported by two 155.9-cm wide by 414.0-cm deep steel box girders. This is a 699.5-m long six span bridge over the Yukon River located near the Arctic Circle on the gravel road section of the Dalton Highway. The bridge is located approximately 80 km north of Fairbanks, Alaska. The structure was designed in the early 1970's with a 127-mm two-layer timber deck wearing surface. Since then, the timber deck wearing surface has been replaced in 1981, 1992, 1999, and 2007. Future decking material may be composites. Factors to be considered in the selection of a new decking material include: thermal cracking, abrasion, durability, flexural strain, traction, weight, and fastening methods to the steel deck. Moreover, the material must retain its structural properties in temperatures that range from -50C to 40C. For a majority of the year, the driving surface is covered with ice and snow. Because of the steep grade, trucks typically use tire chains during the winter. These tire chains damage the current timber wearing surface and are a major factor in its deterioration. Further, the more traffic the less traction. Owing to the damage tire chains cause on the current timber wearing surface, other wearing surface materials are being considered. The purpose of this project was to evaluate possible wearing surface in the laboratory for punching shear, structural strain, modulus, traction, and resistance to tire chains. In this paper, preliminary test results for traction, and wear by tire chains are presented. This is an updated version of a paper that was first presented at ISCORD 2007, Proceedings of the 8th International Symposium on Cold Region Development, Tampere, Finland, September 25-27, 2007, with co-author, J. Leroy Hulsey.