GEORGIA — The Halloween storm continues to disrupt traffic on I-89. On Thursday, the Vermont Agency of Transportation (VTrans) will close one lane southbound north of Exit 18 as part of its efforts to repair a 580-foot culvert damaged by the storm.
The closure will take place at 9 a.m., after the morning commute, and will last for three weeks, VTrans said in a statement.
The culvert runs under all four lanes of I-89 and Skunk Hill Road in Georgia. It is 30 feet below ground.
During the Halloween storm water flowed through perforations in the culvert, increasing the size of those perforations and washing away sediment around the culvert. There was then settling around the culvert, which led to the closing of a northbound lane on I-89, explained Kristin Higgins, the structures program manager for VTrans. Higgins is personally heading up this project.
Replacing the culvert would have cost $12 million and caused extensive traffic disruption.
Instead, VTrans will be inserting a liner, essentially “a pipe within a pipe” into the culvert, said Higgins. The cost is for this approach is $5 million.
Phase one will be inserting the liner and grouting around the edges. Phase two will be shoring up those areas where settling has occurred and reopening the northbound lane, she explained.
The work must be completed by the end of April to qualify for federal assistance.
VTrans has already replaced a culvert under the southbound ramp at Exit 18, which cost $2.5 million. That culvert was more severely damaged, said Higgins.
“We were really lucky,” she said of the 580-foot culvert. That culvert held its shape, making it possible to insert the new pipe within it.
Inserting the liner is the most cost effective repair option, said Higgins. The new pipe also has a 50-year life.
Asked if there was anything in particular about this area which caused two culverts to fail, Higgins said it was simply the result of where the storm occurred.
“A culvert doesn’t rear its ugly head so quickly,” said Higgins. “It takes a while to se there’s been damage.”