SCDOT answers Wando Bridge questions
On June 29, Brittany Peacock, Public Information Coordinator for the South Carolina Department of Transportation provided these responses to additional questions SCDOT received from several media outlets regarding the I-526 Wando Bridge, which was closed from May 14 until it re-opened on June 2. The closure caused extensive traffic problems for Daniel Island and the entire Charleston area. Structural concerns and possible additional traffic closures remain a concern for area residents.
1. Was duct tape used on connections in 2010? If so, why and how long was the duct tape applied to those connections on both the east and west bound sides of the Wando Bridge? The actual connections were not made using duct tape. Duct tape is present but it appears that it was used to help cover grout ports (holes where the grout was originally injected).
2. There were numerous cracks on the eastbound side of the Wando Bridge in 2012. Were those cracks sealed? Cracks are common in concrete bridge structures and monitored through the normal bridge inspection process. Any cracks that impact the structural integrity of the bridge would be repaired as directed by an engineer…There are no cracks in the structure that create a structural or safety concern.
3. According to the 2010 inspection report findings, water intrusion was also found on the eastbound side of the Wando Bridge. What steps did SCDOT take after the water intrusion was discovered on the eastbound side? In August 2011, SCDOT patched and sealed over 2,400 grout holes on the structures, including 1,522 locations on the eastbound structure.
4. Do you have any details about lane closures overnight on the westbound side of the Wando Bridge? We noticed cones out early on a recent morning. And do you know if any more lane closures are scheduled? SCDOT is placing temporary concrete barriers to continue to work on the structural redundancy implementation for both bridges.
5. DOT has been doing some 526 bridge repair staging on DI, under 526, specifically next to the tennis center. How long might they be there, as the City/DNR is supposed to be eventually using that property for boat landing parking? Will DOT be permanently using that property for bridge things? Any way you can try and see what their intentions are? Berkeley County had been using part of that property for recycling containers for residents and again, the future City plans? SCDOT has used and will continue to use this area for staging and storage of materials and equipment for bridge maintenance projects. There are currently no approved permits for non-SCDOT use.
6. While there were several inspection reports provided from reviews done by outside engineers we saw no status updates, emails or reports related to the weekly examinations of the James B. Edwards Bridge that DOT started after a corroded cable needed repairs in 2016. Were those weekly reviews documented in some fashion? If so, how can we access those documents? Information related to the weekly examinations can be accessed from SCDOT’s website at the following link, under “Asset Management”, “Wando Tendon Monitoring” - https://www.scdot.org/travel/travel-wando-closure.aspx.
7. The documentation provided by DOT appears to show actual traffic counts on the bridge for that time period but not the projections for traffic volume. We are interested in seeing what was projected for comparison with actual counts. The original bridge construction plans show a projected average daily traffic (ADT) of 32,800 for I-526 (east and west bound combined) for year 2007. Actuals from 2007 were 54,200 vehicles per day (combined eastbound and westbound). The increased traffic volumes lead to congestion and lower travel speeds on the route; it does not cause any concern about structural loading.
8. Is there additional documentation that was not immediately available? SCDOT has completed the historical record and additional documentation can be accessed from SCDOT’s website at the following link: https://www.scdot.org/travel/travel-wando-closure.aspx
9. What exactly was done to fix the problem? 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.
10. Could the same thing happen with other elements of the bridge? Anything is possible, but SCDOT is taking a proactive approach and providing redundancy. Health monitoring to maintain real time awareness of the bridge performance is also being implemented.
11. What happened to the broken cables and damaged cable (after the breaks)? A forensic analysis was performed on the cable to help identify the specific cause of the failure. The cable is currently being removed and replaced.
12. 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.
13. Are there other bridges in S.C. similar to this one that you have now inspected to make sure this is not happening with those? The I-526 over Wando structures are the only post-tensioned concrete segmental box bridges in the state.
14. Is there any way to ensure that this doesn’t happen at all (preventative)? SCDOT will continue preventative maintenance activities as the structures age along with providing structural redundancy.