Sunday, March 30, 2014
by Rick Steelhammer
EAST LYNN — Thanks to composite materials and a WVU-designed bridge rehabilitation project, a badly rusted span providing access to a campground at East Lynn Lake has been saved from possible demolition. The span will open to traffic as scheduled in May, and should serve campers for decades to come.
The project also saves taxpayers more than $135,000, since the rehab work was done at 60 percent of the cost of conventional repairs and could serve as a national demonstration project for government agencies dealing with infrastructure construction and maintenance.
The 40-year-old bridge spanning the East Fork arm of East Lynn Lake had been reduced to one traffic lane, a six-ton weight limit and a 10-mph speed limit because of severely corroded steel support pilings. Officials with the U.S. Army Corps of Engineers’ Huntington District, which manages East Lynn Lake, were considering closing the span after structural engineers found that up to 50 percent of some of the steel pilings supporting it had corroded away.
Happily, a solution to the problem of repairing the bridge was in the works. In 2009, the Corps’ Engineering Research and Development Center became interested in testing the viability of using composite materials in public works projects to enhance durability and reduce maintenance costs.
A contract to conduct the study was awarded to West Virginia University’s Constructed Facilities Center, a unit of the university’s College of Engineering and Mineral Resources. There, Dr. Hota GangaRao, director of the CFC, had been working on ways to integrate composites into infrastructure construction and repair since the late 1980s.
With support from the National Science Foundation and the Corps’ R&D division, GangaRao and WVU were commissioned to test possible uses of composites on six Corps of Engineers projects, ranging from the installation of new emergency gate recess filler panels made with fiber reinforced polymers at Willow Island Lock and Dam in Pleasants County to repairing concrete lock discharge ports at Tennessee’s Chickamauga Lock and Dam by wrapping them underwater with reinforced polymer fabric.
The East Fork Bridge is the largest of the six sites involved in the research project.
John Clarkson, a structural engineer with the Huntington District and a former student of GangaRao, praised the work ethic of the WVU engineering students who spent hands-on time working on the bridge, helping complete the repairs in less than the allotted time, in spite of weeks of unfavorable weather.
“They really jumped in here and helped us,” he said.
“The students were here two or three days a week,” said GangaRao, who was at East Lynn Lake on Thursday, as a crew of engineering students removed scaffolding from the just-completed bridge rehab. “The actual construction time here was about two and a half weeks. Without the students, we couldn’t have finished here that soon.”
While repairing the bridge through conventional means would have required welding, scraping and painting to fix the bridge piers, the WVU-Corps of Engineers project made that irrelevant.
To repair the East Fork Bridge, quarter-inch-thick, 20-inch-diameter jackets of fiber-reinforced polymer were placed around the corroded H-beams that made up the bridge piers. Next, sheaths of fiberglass-reinforced polymer were wrapped snugly around the jackets. Finally, soupy self-consolidating concrete was pumped into the voids separating the beams from the polymer jackets.
The concrete and the polymers that encase it provide three layers of protection against future corrosion and give the bridge more than twice its original strength.
Welders or other special equipment were not needed to rehabilitate the Wayne County bridge, since “the composite jacket that goes around the piles is fastened with screws, and the fiberglass polymer that wraps around it is applied by hand,” Clarkson said. “All the composite material used was bought off the shelf.”
GangaRao said sensors that measure corrosion, humidity and temperature have been installed in the bridge. “We’re using a solar panel to run it,” he said.
“Good stuff is happening here,” said Col. Leon Parrott, commander of the Corps’ Huntington District, who inspected the bridge Thursday. “When you can combine innovation with teaching and research to protect our infrastructure, it’s a good thing. The technology used here can be used statewide and across the nation.”