What are the columns doing inside the Detroit-Windsor Tunnel?

[roadman65]

I noticed that inside the tube of the Detroit-Windsor Tunnel around the curve on the Detroit side there are piers in the middle of the two lanes that seem to be holding up the tunnel ceiling.  What is up with these?  Is the tunnel in danger of collapse or is it to prevent trucks from straying over the center line around the curves?

[thenetwork]

I noticed that inside the tube of the Detroit-Windsor Tunnel around the curve on the Detroit side there are piers in the middle of the two lanes that seem to be holding up the tunnel ceiling.  What is up with these?  Is the tunnel in danger of collapse or is it to prevent trucks from straying over the center line around the curves?

Correct me if I'm wrong, but I believe that the columns you mention have been there since Day One.  That particular "curve" area is not under the Detroit River, so it is probably just a different way of "supporting" the tunnel over land.

[roadfro]

^ There's a video of this tunnel on it's Wikipedia entry. Taking a look at that, it appears the tunnel widens out on the Detroit side as it goes around those curves. Perhaps the columns are there to support because of the excess width, knowing there may be stuff above the tunnel ceiling due to cut-and-cover construction?