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Infrastructure Technology Institute

Midwest Bridge Working Group

Prof. Robert Connor of Purdue University presents applied research results at the Winter 2010 Midwest Bridge Working Group meeting

The Midwest Bridge Working Group (MBWG), a technology transfer forum sponsored by ITI and operated by the University of Kentucky, held its winter meeting December 13-14, 2010. The meeting was hosted by the Indiana Department of Transportation at the Indiana Government Center in downtown Indianapolis.

In spite of blizzard conditions across the region on the day before the meeting which forced many people to cancel travel plans, the meeting attracted 118 people: 47 state department of transportation personnel representing 14 states, 13 researchers representing five universities, two Federal Highway Administration representatives, and the balance representing consultants, vendors, and industry.

The meeting was divided into a full day of maintenance, inspection, and safety topics of general interest to bridge professionals followed by a half-day session dedicated exclusively to coatings for steel and concrete bridges.

Harry Capers of Arora & Associates kicked off the meeting with a presentation on the findings of National Cooperative Highway Research Program project 20-24(37E) on sharing best practices among state departments of transportation. Several subsequent presentations showcased recent research studies and performance evaluations by state departments of transportation. Chris Keegan of the Washington State DOT presented the results of a bridge washing pilot project to establish a procedure by which the benefits of power-washing bridges to remove salt residue and other corrosive debris could be realized without causing environmental problems in the river below the bridge. Michael Sprinkel of the Virginia DOT presented a case study on the failure and repair of a deck closure pour (the strip of concrete that completes the deck of a bridge between two girders), which included an investigation of the failure mechanism and recommendations for repair. Scott Neubauer of the Iowa DOT and Jeremy Shaffer of InspectTech Systems discussed the development of a bridge inspection data management system for Iowa. Bruce Brakke, also of the Iowa DOT, re-examined a number of fractures in Iowa steel girder bridges over the past 30 years in light of lessons learned in the Hoan Bridge failure in Milwaukee in December 2000.

Prof. Robert Connor of Purdue University presented results from two research projects. The first was a fitness-for-purpose investigation of the US-41 bridge over the White River in southern Indiana. The bridge was to be subjected to extremely heavy permit truck loads due to construction of a power plant in the area. Prof. Connor presented his team’s analysis of the bridge for various limit states under the expected loads and then compared the predictions to data acquired from sensors on the bridge as heavy trucks crossed. Prof. Connor’s second presentation was a discussion of advanced computer image analysis to identify out-of-plane bending and other performance problems on gusset plates.

Ted Zoli of HNTB gave a presentation on a rare but serious bridge safety incident: hydrocarbon fuel fires on bridges. Recalling the 2007 gasoline tanker fire and subsequent collapse of the I-580 “MacArthur Maze” connector in Oakland, California, and similar incidents, Zoli discussed the mechanics of hydrocarbon fires as they related to bridges and ways to mitigate the risks and respond to bridge fires.

Vendor presentations included a selection guide for bridge deck joints and seals, hydrodemolition for repair of concrete bridge elements, automated entry of inspection data using tablet computers, new non-destructive testing methods for bridge decks, and acoustic imaging for underwater bridge inspection in situations where diving would be unsafe.

Recognizing that protective coatings (including, but not limited to, paints) are critical for preservation of bridges, the second day of the meeting was devoted exclusively to coatings. Presentations included improved methods for field measurements of surface profiles, performance evaluation of one-coat paint systems on new steel bridges, weathering performance of various polyurethane coating formulations, new coating systems for bridges, inspectability of certain coating systems, and the results of a 20-year study of bridge repainting system performance.

The next MBWG meeting will be held in June 2011 in St. Louis.