Officials said that “non-structural concrete at an expansion joint” below Huntington Avenue became dislodged and fell into a ...

Authorities are on-scene after piece of concrete fell from the top of a downtown Boston tunnel on the road below.

MassDOT said a section of "non-structural concrete at an expansion joint" under Huntington Avenue fell into a travel lane Friday afternoon.

Expansion joints are the long strips you see between sections of road on a bridge. They allow the concrete to move without cracking in conditions like extreme heat. This is not an uncommon issue.