Mold can grow anywhere — even on the Delaware Memorial Bridge. That could spell danger for drivers if it goes unchecked.
Operators of the bridge put a $35 million dehumidification system into operation in October 2017 designed to protect bridges.
The problem? Humid air. When it reaches the steel cables that support one of the world’s largest suspension bridges it can create a $1 billion problem.
To prevent any potential cable failures and danger to motorists, operators of the bridge, operators decided to use the technology. The Delaware Memorial Bridge is only the second bridge in the U.S. to do so.
“This is an investment in the future and something that will lengthen the lifespan of this bridge,” said Delaware River and Bay Authority Executive Director Thomas Cook. “It’s a small investment which will pay dividends for years.”
Cook and several authority officials and members of the team which installed the cable preservation system donned hardhats and safety vests as they ventured inside the New Jersey anchorage on the Delaware-bound span of the bridge to show off the new, small room which houses the dehumidification plant. Identical rooms like it have been installed in each of the three other anchorages on the twin spans. With just a flick of a switch, they put the system into operation for the north cable on the span of the bridge.
“The primary goal is to extend the lives of the main cables that form the suspension bridge and carry the load from the suspended spans,” said DRBA Project Engineer Shekhar Scindia. “The main cables are the most critical components of the suspension span.”
American Bridge Company of Coraopolis, Pa., was awarded the contract and began installation of the dehumidifier in 2016. The project is expected to be finished in the spring of 2018.
Part of the project includes installing wraps around two 4,100-foot-long cables on both two bridges. That process can be seen by those who drive the bridges as workers uses the suspended walkways following the cables from the road surface to the top of the bridge towers.
The high-tech dehumidification units were installed inside the bridges’ anchorages, and air injection and exhaust ports are positioned along the cables.
The system works by forcing dry air through the entire length of the cable which pushes out the moist air. The cables are made up of about 8,000 single strands of steel wire which air can travel between.
An inspection found some signs of corrosion already taking place on the bridge cables about five years ago, so the dehumidification system was seen as a proactive step, officials said.
The system is paid for through toll receipts and equipped with remote sensors and advanced monitoring systems to ensure it is functioning as intended.
The bridges connecting New Jersey and Delaware carry about 70 million vehicles each year and are a key transportation link along the Northeast Corridor between Washington, D.C. and New York City.
Source – NJ