Less than standard grade concrete was used in the Big Dig and now there are concerns that it might start leaking and falling apart. Well, more than it already has.

'The worst-case scenario is it collapses," said Paul J. Tikasky, a civil engineer at Penn State University and a board member of the American Concrete Institute. ''It depends how bad it is, but it could happen, sooner than later."

Michael Sullivan says that's over the top and there's no reason to doubt the structural integrity of the Dig. He's probably right. After all, U-Mass Boston is still standing thirty years after the MBM scandal.

But if you want to see the effects of sub par concrete and what those shiny new Big Dig tunnels might look like in a few years, take a ride through the parking garage at U-Mass in Dorchester. It ain't pretty.