JACKSONVILLE, Fla. -

The Mathews Bridge is still standing, and that is pure luck, according to bridge designer and University of North Florida civil engineer professor Adel ElSafty.

"We got lucky because the extent of damage was not as severe as it could have been, and the magnitude of force was not significant enough to cause this kind of collapse," ElSafty said.

But he said the bridge is being closely monitored for future collapse.

The missing piece, called a member, was holding up part of the bridge. With the member missing, that force has to be supported somewhere else.

"It's about the shift and the movement. Did that structure move? Did it shift? Did the support move somehow?" ElSafty said.

He said the underside of a bridge is designed for impact from a ship. For instance, the Dames Point Bridge has pilings designed for impact and a structure on the outside to make sure that ships do not hit the pilings.

But whether it's the Dames Point Bridge, built in 1989, or an older bridge like the Mathews, ElSafty says the top side of a bridge is never designed for impact.

"I think people have underestimated the significant damage to the bridge as a result of this collision from the start," he said.

Maritime attorney Rod Sullivan also agrees it's luck the bridge is still standing. He believes someone mismeasured the draft of the ship, the height of the ship and the impact of the tide.

Sullivan said those measurements should have been confirmed by the Coast Guard when the plan to transport the ship was approved.

And a harbor pilot should have been on board. Harbor pilots have intimate knowledge of the water and are licensed by the state of Florida, but because this was a federal ship, a pilot wasn't required by law.

"It's penny wise and pound foolish to transport a ship like this without a state licensed harbor pilot on board," Sullivan said.