What Engineers Should Learn from the Big Dig Tragedy

The dust has settled from the Big Dig tunnel collapse in Boston two years ago, but there are still important lessons for engineers to learn from the fatal tragedy, which was easily avoidable.

“The message still hasn’t adequately penetrated enough that when engineers are dealing with new materials, they should use caution with the sources that they rely on,” says Myer Ezrin, a failure analysis expert and former researcher at the University of Connecticut’s Institute of Material Science. “Engineers working with material they have little or no experience with — particularly if it is a life and death matter as it was in the Big Dig — have to investigate the choices and then confirm that investigation.”

In Ezrin’s view, these are the engineering errors made in the ceiling of Boston’s Interstate Connector Tunnel:

The wrong material was chosen as the adhesive to hold up the concrete panels as a suspended ceiling.

There was a communication breakdown between the construction engineers and the resin suppliers’ engineers.

Engineers failed to adequately investigate why anchor bolts using the same adhesive in another tunnel failed in 1999.

Use of a suspended ceiling, particularly one made from concrete, was a mistake in the first place.

On July 10, 2006 a passenger car traveling to Boston’s Logan Airport passed through the D Street portal of the Interstate 90 connector tunnel in Boston, part of a project often referred to as the “Big Dig.” As the car approached the end of the tunnel around 11 p.m., 26 tons of concrete panels fell, killing a passenger. The panels were part of a suspended ceiling anchored to the concrete roof with threaded bolts in an epoxy-filled hole that had been drilled. Massachusetts Attorney General Martha Coakley charged epoxy supplier Powers Fasteners of Brewster, NY, with one count of involuntary manslaughter, which carries a maximum fine of $1,000. Other contractors avoided possible criminal charges with a $450 million settlement with state and federal officials