ENGLISH CENTER - Fiberglass probably isn't the first thing that comes to mind when people think about building bridges, but that may change some day, thanks to an experimental project nearing completion on a bridge over English Run.
Workers from State College-based Glenn O. Hawbaker Inc. recently began replacing the bridge's steel grate deck with a deck made with a type of fiberglass called fiber reinforced polymer - or "FRP."
The deck is the first of its kind in Lycoming County, said county transportation planner Mark Murawski.
Workmen install an experimental fiberglass deck on a bridge spanning English Run in English Center. The deck, the first of its kind in Lycoming County, can be installed in about two weeks, while a concrete deck takes two months to complete.
According to Duane Daniels, an engineer with Larson Design Group overseeing the project, 5-inch by 5-inch lengths of FRP tubes glued together into rectangular sections comprise the base for the deck. Gravel is glued to the top of the panels to secure a concrete wearing surface, Daniels said.
"The tubes actually have higher tensile strength than your typical steel reinforcement," said Jerome S. O'Connor, president and CEO of Bridge Composites LLC, the Hornell, N.Y.-based company distributing the deck.
According to O'Connor, the strength comes from the fact that the material is composed of continuous glass fibers that run the length of the tubes rather than chopped particles used in regular fiberglass.
The deck must be capable of bearing heavy loads because the bridge provides the only access over the creek for trucks hauling coal for Fisher Mining Co., Murawski said.
The old bridge deck was beginning to deteriorate, and that eventually would have required a weight limit posting on the bridge, he said.
"Mining company trucks need to carry a 40-ton limit," Murawski said. "Imposing a weight limit on the bridge would be a significant economic hardship to the mining company because they have to run truck trips with less weight to get coal to Newberry Yard (in Williamsport) to ship it out by train."
The steel grate deck also allowed salt and debris to collect on the bridge's steel support beams, which corroded the beams, he said.
According to Murawski, the fiberglass deck was chosen to replace the old deck because it could be installed much quicker than concrete; two weeks for the fiberglass deck compared to two months for a concrete deck.
The extended shutdown time for the bridge would have created a financial hardship for the mining company, he said.
"You can't close the mine down for two months. That just wasn't going to work at this site," he said. "We needed something that could be put in quickly."
"The speed of construction is the number one reason why we are doing this at this location," Daniels said. "The mine just can't cease operation for (two months)."
According to Murawski, the new deck is lightweight, which puts less strain on bridge support beams.
"(A single FRP tube) is lighter than a baseball bat," Daniels said. "It hardly weighs anything."
According to Daniels, the steel deck was removed in about four hours. In addition to a new deck, the bridge will receive new steel safety rails and new guide rail approaches, Daniels said.
The question of how to pay for the bridge was answered when federal funding became available for the experimental fiberglass bridge materials, Murawski said. The funding was available with the stipulation the bridge be monitored to determine how the deck stands up to use over time, he said.
The federal government provided $163,000. The remaining cost - $173,000 - was paid for mostly with state Department of Transportation funds and a small amount of county liquid fuels money, he said.
"That was an added bonus," Murawski said. "We could secure more money because we were doing a demonstration project."
The project hit a speed bump after the funding was approved. A deck was ordered from the only fiberglass deck manufacturer in the country, and it went bankrupt.
Murawski said he began searching for another manufacturer and finally found one - in Australia. Bridge Composites LLC distributes the decks for the company.
According to O'Connor, the bridge deck is one of only 120 in the country. That isn't many, given the fact that there are almost 600,000 bridges 20 feet or longer in the United States, he said.
In some countries, the material has been successfully used to build entire bridges, not just decks, he said.
If the deck proves to be successful, it could pay dividends for the entire state, Murawski said.
Pennsylvania has a backlog of bridges in need of repairs and fiberglass could be the answer for many of the smaller spans, he said.
"When we see there are problems with our smaller bridges, we'll take a look at this as a possible alternative," he said. "It opens up a whole new world for us."
"It will probably be 10 years before this is accepted and used on a regular basis," O'Connor said.