Safety of 60-year-old retaining walls questioned after cap collapse on SB Lodge
(WXYZ) – Tonight there is new information about this large piece of concrete that fell from the retaining wall onto the lodge’s highway Friday night.
It happened in the southern lanes near Outer Drive. The motorway is still closed on Saturday evening. Originally reported as the collapse of the retaining wall, MDOT described it as a solid concrete retaining wall cap on the previous Saturday.
About three feet high and at least 200 feet long, it fell from the top of the retaining wall and crashed onto the freeway Friday night, narrowly missing out on oncoming traffic.
“We started closing the lanes south on the M-10, but the freeway itself wasn’t completely closed,” said Diane Cross, a spokeswoman for MDOT.
That was at 8:15 p.m. – 45 minutes before MDOT’s planned highway closure at 9:00 p.m.
“On the service trip yesterday we started to work with what is known as saw cutting,” says Cross.
An investigation is investigating exactly what happened, but at the time of the saw cut, around 8:15 p.m., for some reason the hundreds of feet long section of concrete from the driveway fell onto the highway pavement and brought a worker to the ground with it.
This worker was taken to the hospital. Its condition is still unknown.
Many wonder, could it happen again? Are these 60 year old retaining walls safe to drive on?
“Because of the age of the walls, they’re inspected every three months, and we now have the inspectors out here,” says Cross.
The retaining wall is to be replaced in the spring. The work previously planned for this weekend was to remove the pressure on the retaining wall out of caution.
The cap would always be removed, just not that way. It was planned to be removed after the autobahn shutdown. A three-meter-high slope is being dug behind the retaining wall, which is also part of the original plan, but now also allows for further inspection. By removing the debris, the pressure is released and the crew can inspect the 35-foot steel rebar that hold the wall in place. These rebars are anchored and enclosed in concrete.
“We can also examine the other side of the walls and that will be part of the design that will be done over the next few months,” says Cross. “And then we’ll rebuild these walls in the spring.”
The southbound lanes of the M-10 are expected to reopen on Monday. MDOT says lanes will remain closed if inspectors believe there is a safety issue.
The service trip will be closed for the next few months.