The Big Crumble – Probes; evidence; memos

| July 28, 2006

While the State of Massachusetts has been carrying out its own investigations, the National Transportation Safety Administration has started its own separate probe into the causes of the Big Dig Crumble’s collapse earlier this month (via Andrew Miga at the Associated Press via Forbes):

Federal investigators are looking into whether vibrations from nearby construction could have shaken loose bolts in a Boston highway tunnel, allowing its massive ceiling panels to collapse on a passing motorist….

Federal officials have so far issued 12 subpoenas to Big Dig contractors, subcontractors and others since the collapse, Lynch said.

The subpoenas closely mirror ones issued in a state criminal probe that could result in involuntary manslaughter charges.

State Attorney General Tom Reilly said Thursday that he was focusing on the work of project manager Bechtel/Parsons Brinckerhoff and its limited liability contracts with the state, though he emphasized no one involved was “off the hook.”

Some of the 40,000 documents gathered so far in the state probe make it clear that project officials were concerned as far back as 1999 about whether the epoxy anchor bolt system could support the 3-ton ceiling panels.

“Now we have to find out, what did they do about it?” he said.

A spokesman for the company did not immediately return a call seeking comment.

The NTSB, in that same briefing, noted that workers damaged critical evidence regarding the tunnel’s collapse (via Casey Ross at the Boston Herald):

Critical evidence in the Big Dig criminal probe has been compromised because a worker dislodged key bolts with a sledgehammer after the collapse, a mistake that could hurt efforts to pinpoint blame for the fatal failure, federal authorities said.

>Lawmakers briefed by the National Transportation Safety Board said the damage to the evidence, which appeared to be inadvertent, has caused concern among investigators trying to reconstruct the collapse and decipher its precise cause.

“In some cases, it could have decreased the evidentiary value of (the bolts),” U.S. Rep. Stephen Lynch (D-South Boston) said, adding that the unknown worker apparently was trying to collect bolts for investigators, but left some badly damaged.

In the meantime, Timothy Noah over at Slate has gotten a jump on the Smoking Gun and actually published a Big Crumble document — meeting minutes from a January 10, 2000 meeting, in which (among other things) someone raises concerns about the epoxy used to hold in the infamous bolts:

There has been an apparent failure of the epoxy for some direct attach ceiling anchors in the first 100 feet of the tunnel. This has resulted in repairs and additional testing.

Here’s hoping Noah and/or the Smoking Gun people get their hands on more documents. However, this particular memo is cited by Mass Att’y General Tom Reilly in his claim that the Big Crumble’s top officials and engineers knew of these and other problems (again via Casey Ross at the Boston Herald):

The early failures of Big Dig ceiling supports were known by the project’s top officials and engineers, Attorney General Tom Reilly aid today, announcing that criminal investigators are following a chain of mistakes that leads to the highest levels of the $14.6 billion project.

”At the end, we will have answers and we will find out who is responsible and will hold companies accountable all the way up, including Bechtel (Parsons Brinckerhoff),” Reilly said this afternoon.

Reilly, who is leading the criminal probe, confirmed a Herald report yesterday that revealed project officials knew of problems with epoxy bolts in the section of the I-90 Seaport Connector tunnel where Milena Del Valle, 38, was killed July 10.

“I don’t think there is any question that those companies knew that there were problems with the installation of the (epoxy) system in that area,” Reilly said. ”I don’t think there is any question about that.”

A January 2000 memo obtained by the Herald showed that top project officials were discussing failure of epoxy sealing supports ”in the first 100 feet of the tunnel.” The collapse that killed Del Valle occurred within the first 200 feet of the tunnel, investigators have said.

And, to back up Reilly’s claims, here are some more examples of problems that Big Crumble officials and engineers knew about and chose to ignore (via Scott Helman and Sean Murphy at the Boston Globe; emphasis mine):

Managers overseeing construction of the ill-fated ceiling in the Interstate 90 connector tunnel in 1999 were baffled to see ceiling bolts “creeping out” of their holes even after they had passed a strength test, according to engineers’ notes.

One bolt had slipped out of the concrete roof by more than a half-inch two months after passing its original strength test, and when workers retested the bolt, it “began to pull out with almost no resistance….

…In 1999, the failure of bolts after their initial testing led Big Dig managers to require testing of the bolts with more weight, but only after more than 80 percent of them had already been installed, according to a memo from the ceiling’s builder, Modern Continental Construction Co. There are no records that workers ever went back and retested those bolts, which are held to the tunnel roof with epoxy….
…Yesterday, one structural engineer said the tunnel ceiling should have been built with a wider margin of safety. More than 80 percent of the bolts apparently were tested up to a weight of 3,250 pounds, when the load they were supposed to carry was about 1,400 pounds. And the bolts passed if they held the test weight for only a few minutes.

“You’re talking about a real, measured safety factor of 2.4, which is too low for this type of application, no question about it,” said Stephen Buonopane, assistant professor of engineering at Bucknell University in Pennsylvania, referring to the ratio between the weight at which bolts failed tests compared to the weight they would normally bear. “It should have been obvious to people.”

He said the margin should have been at least 4 to 1, requiring tests of at least 5,000 pounds on each bolt.

Officials who oversaw the $14.6 billion Big Dig said yesterday they were relying on assurances from the company that supplied the ceiling bolts and epoxy, Powers Fasteners of New York, for their confidence in their strength. A senior Big Dig manager said Powers Fasteners had assured officials that the bolts could hold more than 20,000 pounds each, so they never expected the bolts to give way when tested with just a few thousand pounds. Officials at Modern Continental and Powers Fasteners declined to comment.

The Big Dig engineers’ field notes from 1999 and 2000, stored in archives at the secretary of state’s office, reflect concern among Bechtel/Parsons Brinckerhoff officials as an increasing number of epoxy bolts came loose when a weight of 3,250 pounds was suspended from them. In the first week of August, 1999, 14 out of 138 bolts, or 10 percent, failed their strength test and had to be replaced.

Of particular concern was the fact that at least five bolts seemingly held the weight, but then started to move later. One bolt passed the strength test on July 30, 1999, but moved more than a half-inch by Oct. 8. When workers pulled it out, they discovered most of the bolt was bare, suggesting that too little epoxy was used, and the epoxy still on the tip “was brittle and easily crumbled,” Bechtel/Parsons Brinckerhoff engineer Jim Barrett wrote, suggesting the two ingredients of the epoxy were not mixed properly. He also wrote that dust adhered to the epoxy, suggesting that the drill hole had been improperly cleaned….

…Eventually, Bechtel/Parsons Brinckerhoff called for testing all bolts with weights of 6,350 pounds. By then, work crews had already hung concrete ceiling panels from 1,000 of the epoxy bolts, and more testing would have required them to pull the panels back down. One construction official estimated that such a job would have cost at least $600,000.

No one has been able to find records that the ceiling bolts were ever retested, and construction officials involved in the Big Dig say it is highly unlikely that such expensive work would have been permitted, especially since Big Dig chief James J. Kerasiotes was zealously looking for ways to cut the Big Dig’s bloated price tag. If someone had pitched a costly retesting program, said one construction industry specialist formerly involved in the Big Dig, “the answer would not just be no. It would be hell no.”

And there you go. This is a classic project failure anti-pattern: schedule and budget pressures lead to sloppy work, then when quality testing uncovers problems, they are swept under the rug by pleading the same schedule and budget pressures. Quality work and quality testing in projects saves money, time and liability — but it’s so hard to get that across to upper management. ..bruce..

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Category: Main, Project Management, The Big Crumble

About the Author ()

Webster is Principal and Founder at Bruce F. Webster & Associates, as well as an Adjunct Professor of Computer Science at Brigham Young University. He works with organizations to help them with troubled or failed information technology (IT) projects. He has also worked in several dozen legal cases as a consultant and as a testifying expert, both in the United States and Japan. He can be reached at, or you can follow him on Twitter as @bfwebster.

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