Engineers with the West Virginia Division of Highways (WVDOH) have been hard at work designing a solution for a massive sinkhole impacting Route 20 in the Summers County town of Hinton, where bridge crews from several counties gathered this past weekend to erect a temporary bridge, which was open to traffic on Sunday, Nov. 20.
The sinkhole is unlike any other, with a very fine ash material washing away beneath both a police station and the roadway itself. Lead discovered in the material makes the permanent solution more difficult, but a long term repair is also underway.
“West Virginia Division of Highways’ workers are the best in the country at incident management,” said Secretary of Transportation, Jimmy Wriston, P.E. “Time and time again, they prove they can get in and get the work done. They work together, as one Department of Transportation.”
Joe Pack, P.E. Deputy State Highway Engineer of Operations, said a 90-year-old drain under the road began failing in June, leading to the collapse. While the WVDOH is used to repairing clogged or collapsed drains, the sheer size of the problem in Hinton required an unconventional approach.
WVDOH work crews installed a 120-foot temporary culvert and fill material under the road, but heavy rains from Hurricane Nicole on Friday, Nov. 11, washed out the fill and made the sinkhole worse.
The quickest way for WVDOH to ensure continued safe travel on WV 20 in the area of the sinkhole was to build a temporary bridge beside the hole. The WVDOH employed a prefabricated bridge “kit” manufactured by the Mabey Bridge Company for the job.
The bridge is made up of prefabricated beams and trusses which can be assembled on site without the need for special tools or construction methods. The main components of the bridge arrived in Hinton the morning of Friday, Nov. 18, and WVDOH crews began bolting the sub-assemblies together.
“We just put it together like a big Lego set,” Pack said. A similar temporary bridge was recently installed at Laneville in Tucker County to replace a bridge that had been closed for safety reasons.
A crew of 16 men and women from District 9, District 10, and WVDOH Central Forces spent most of Friday and Saturday bolting the bridge together. With Thanksgiving approaching, they were thankful the snow flurries did not turn into heavy snow. The main span was completed on the evening of Saturday, Nov. 19, and the bridge reopened to traffic at about 2:30 p.m. Sunday, Nov. 20.
The temporary bridge is 11 feet, nine inches wide and has an overhead clearance of 13 feet, six inches because of overhead power lines. The temporary bridge will be in place until the WVDOH can complete repairs to the existing culvert to restore water flow under the road until a permanent, 300-foot steel drainage structure can be installed. The WVDOH hopes to put the permanent repair out for bid by the end of 2022.