LONG RAPIDS TOWNSHIP - Engineers will spend this morning investigating the cause of a huge hole that formed under one of the old foundations of a M-65 highway bridge that crosses the north branch of the Thunder Bay River. A $2.678 million replacement bridge is under construction near Maple Lane Road, and the old structure is being used to handle traffic.
The 6-by-10-square-foot void six feet deep was discovered at 12:30 p.m. after a truck crossed the bridge only to get hung up when its rear axle collapsed through the pavement, Eric Precord, transportation coordinator with the Michigan Department of Transportation service center in Alpena, said.
"It looks like some type of erosion," said Precord, who was at the site Friday evening. "There was nothing in the preliminary work to ever show that was down there."
The old bridge and the abutment did not collapse, and no one was injured, he said.
Meanwhile, a detour has been set up with flashing message signs at each end of the closure providing motorists with the latest information, he said:
* northbound motorists on M-65 should head east onto Long Rapids Road, go north on Bolton Road and pick up Long Lake Highway to get around the obstruction.
* southbound M-65 motorists should take Long Lake Highway east to Bolton, then south and pick up Long Rapids Road west.
Although weight restrictions are still in effect for Alpena County, ending Wednesday, truck traffic will be allowed to use the detour, because it is an emergency situation, Precord said. Presque Isle County roads are considered all-season, and do not have weight restrictions.
The $2.678 million replacement bridge has been under construction since mid-February and motorists were using one lane of the old bridge to cross the river.
When construction is completed around Labor Day, depending on delays, the new bridge will consist of two 60-foot wide spans of prestressed concrete. The bridge also will be wider than the original structure.
Betsy Lehndorff can be reached via email at firstname.lastname@example.org or by phone at 358-5693. Follow Betsy on Twitter @bl_alpenanews.