The S.C. Department of Transportation has answered some of the lingering questions surrounding the sudden closure and later reopening of the James B. Edwards bridge that snarled traffic across the Charleston region after a cable snapped in May.
The DOT addressed a question several people seem to have asked after seeing some of the damage to the bridge: Did the agency make repairs with duct tape back in 2010?
“The actual connections were not made using duct tape,” the DOT said in a series of written answers. “Duct tape is present, but it appears that it was used to help cover grout ports.”
The answer further explained that “grout ports” are holes where grout is injected into the structure to fill gaps.
Most of the other questions and answers focused on inspections of the bridge and some of the ongoing work happening after the majority of the westbound lanes of Interstate 526 reopened.
For example, could other bridges across the state face similar issues with cable corrosion and failure?
While it’s possible for damage to occur to any bridge over time, the DOT said that the bridge of the Wando River is the only one of its kind in the state. The segmental box bridge design includes pre-stressed, concrete segments that are reinforced with cables and tendons running under and across the bottom of the bridge.
One of the most eye-opening data points showed the Wando bridge is handling 65% more vehicles per day than originally projected.
The DOT said the Wando bridge was projected to handle 32,800 vehicles a day in 2007 on the westbound and eastbound lanes combined. However, 54,200 vehicles per day actually used the bridge that year, the agency said.
“The increased traffic volumes lead to congestion and lower travel speeds on the route; it does not cause any concern about structural loading,” the DOT said.
More questions and answers can be found here (.pdf), and the S.C. DOT has a public documents page for those interested in the details of the bridge closure and the status of the repairs. Here are some of the questions and answers regarding the more immediate structural issues:
- What are the recent lane closures overnight on the westbound side of the Wando bridge for?
“SCDOT is placing temporary concrete barriers to continue to work on the structural redundancy implementation for both bridges.”
- What exactly was done to fix the problem of the tendon embedded in the concrete on the westbound side that needed to be replaced?
“Two additional tendons were installed to provide additional structural support in place of the ruptured tendon. The ruptured tendon is currently being removed and replaced.”
- What was done to ensure that none of the other cables will break or become damaged?
“SCDOT has performed extensive testing, will provide redundancy by installing additional tendons and implement real time monitoring.”