All eyes have been on the aging Herbert C. Bonner Bridge over Oregon Inlet for the better part of the past two decades as the North Carolina Department of Transportation and other federal and state agencies figured out how to replace it.
However, concerns about Hatteras Island?s only land link have soared since DOT closed the bridge for safety reasons for 12 days in December. That came after a routine sonar test on the bridge?s bents ? or piers ? showed serious scouring of the sand around one particular area.
So when DOT announced a few weeks ago that the bridge would close for 30 minutes on Monday, March 10, for a routine scan of the bridge, it got the attention of many folks who worry about the span?s safety and their passage on and off the island by highway.
And all this comes while DOT?s plan to replace the bridge with a parallel span and address the ?hotspots? of overwash on Pea Island as they occur is being challenged in state and federal courts by environmental groups.
Construction on the new bridge was scheduled to begin in January of last year. Fifteen months later, it?s still not underway.
Time is indeed running out for the 50-year-old bridge that has served well past its expected lifespan.
DOT is pouring money into repairs to keep the bridge standing until the legal problems are sorted out.
But the department is also being proactive with what we might think of as regular medical checkups.
Lest we continue to fret if DOT makes an announcement about a scan or checkup, it?s good to understand what is happening on a regular basis to keep the bridge safe for the traveling public.
In an interview earlier this week, DOT spokeswomen Nicole Meister and Jennifer Garrifo, along with members of the department?s Location and Surveys unit, explained the regular tests that are being used to check the condition of the bridge.
The latest scans, Meister said, have uncovered no new problems to require another safety closure.
Bent 166 ? the one with the severe scouring of the pilings ? has been repaired, and the contractor, Carolina Bridge Company, has begun a similar project on Bents 162 to 165. NCDOT has monitored scour in this area since December. While the scour at this location is in no way as critical as it was at Bent 166, the department decided to be proactive and move forward with similar work out of an abundance of caution while crews were still mobilized at the bridge.
A complete sonar scan of the bents on the bridge is performed monthly. A sonar scan of Bent 166 is done every two weeks.
The sonar scans should not require closures, Meister said.
However, quarterly and after major storms, DOT performs a top-deck scan.
According to a DOT news release, in 2012, the department installed scanning technology to allow it to closely monitor any movement of the bridge. A series of GPS points are marked along 150 of the bridge?s 200 spans. Each point is surveyed once each season, including before the start of hurricane season, and after each storm to see if it has moved.
The bridge is closed briefly during the top-deck scan. A truck, moving slowly at about 15 mph, moves over the bridge and back again, checking the GPS points. Then the most recent scan is compared to previous ones to check for any unusual movement of the deck.
DOT has promised the public that closures for monitoring the bridge will be brief and announced in advance.
And, of course, the bridge would be closed if the department has any safety concerns.
We all hope regular checkups will keep the bridge going until there is a resolution to the legal issues ? and most of us hope that the federal Court of Appeals will agree with the opinion of U.S. District Court Judge Louise Flanagan of North Carolina?s Eastern District.
Last September, Flanagan ruled in favor of DOT and the Federal Highway Administration in a lawsuit to stop the planned bridge replacement brought by the Southern Environmental Law Center on behalf of its clients, Defenders of Wildlife and the National Wildlife Refuge Association.
SELC appealed Flanagan? ruling last October and recently asked the U.S. Court of Appeals for the Fourth District in Richmond, Va., to hear oral arguments in the case.
A three-judge panel will hear the oral arguments on Tuesday, May 13, at 9:30 a.m. in Room 348 of the federal courts building in Richmond.
The event is open to the public, so you can drop by if you are in the neighborhood.