Engineer suggests adding 900 new support anchors in Ted Williams Tunnel
(David L. Ryan/Globe Staff)
By Noah Bierman, Globe Staff
An engineering firm hired to inspect the Big Dig tunnels following the July 2006 fatal ceiling collapse recommended today that the Massachusetts Turnpike Authority install about 900 new support anchors in the Ted Williams Tunnel.
The anchors would be a backup in 250-foot sections near the tunnel entrances that are impossible to inspect because they were designed without a crawl space. The new supports would fortify epoxy bolts, which were blamed for the fatal ceiling collapse in the Interstate 90 connector tunnel.
"We think this is a viable alternative, cost-wise," said Gary Klein, an engineering consultant from Wiss, Janney, Elstner Associates, which was hired to review all of the authority's roads, tunnels, and bridges.
The ceiling has enough redundant support that the inability to inspect those areas does not pose an immediate safety threat, but it should be addressed within five years, Klein said when he explained the recommendation at today’s monthly Turnpike Authority meeting. The ceiling could also be removed and inspected, but it would probably cost more than adding the 900 support anchors, Klein said.
Klein did not estimate a cost. The fixes would add to the Big Dig’s $14.8 billion price tag, but the authority may be able to use money generated from a settlement with the project's contractors.
The Turnpike Authority has not responded to the recommendation. Klein’s contract expires at the end of June, when he and others are scheduled to make a final report to Governor Deval Patrick.
Klein also recommended retrofitting an additional 180 anchors in the Ted Williams Tunnel that are bolted into unsettled or cracked concrete that may be showing signs of leakage or slippage.
He also recommended upgrading the fire suppression system in the Callahan and Sumner tunnels. Klein said the ventilation system in those tunnels is weaker than others and that any failure could compromise safety.
