Powers Fasteners Issues Documents To Show Big Dig ‘Fault Lies Elsewhere’

Jason Sandefur

In the wake of a federal report on the 2006 fatal ceiling collapse in Boston”s Big Dig tunnel, Powers Fasteners released a statement saying “the events that led to the collapse of the ceiling panels and the death of Melina Del Valle cry out for explanation and accountability. We believe, however, that it would be an untenable conclusion if the federal investigators were to consider Powers Fasteners in any way responsible, since there is overwhelming evidence that the fault lies elsewhere.”
With an unresolved criminal investigation focusing on all 15 companies involved in the Big Dig project, Powers Fasteners revealed to FIN that it has stepped up efforts to defend its actions.
The Brewster, NY-based fastening systems manufacturer has retained communications consultant Karen Schwartzman to handle the media storm over the report.
The National Transportation Safety Board concluded that the probable cause of the July 10, 2006, collapse, which crushed a 38-year-old woman as she and her husband drove through the tunnel, “was the use of an epoxy anchor adhesive with poor creep resistance, that is, an epoxy formulation that was not capable of sustaining long-term loads.”
That finding sparked a public debate over who was ultimately responsible for the use of fast-set epoxy to suspend the 4,600 pound concrete ceiling slabs.
While the report faulted ceiling designer Gannett Fleming Inc. for failing to stipulate which kind of epoxy to use during installation, the NTSB findings also criticized Powers for providing what the board claimed was “inadequate and misleading” information about the limitations of fast-set epoxy – a charge Schwartzman strongly denied to FIN.
She said Powers supplied designer Gannett Fleming, builder Modern Continental, and epoxy distributor Newman Renner Colony LLC with an International Conference of Building Officials (ICBO) evaluation report on Power-Fast epoxy by December 1999. The report, which was incorporated into the final design specifications for the ceiling, made it “very, very clear that there were limitations to fast-set epoxy, which could make it inappropriate to use for long-term live loads,” Schwartzman emphasized.
Company memos supplied to FIN support Powers” claim that as far back as 1999 the company explained the limitations of fast-set epoxy to firms and agencies involved in the Big Dig, including the Massachusetts Highway Department.

” “The Quick-Set anchors have passed all ICBO criteria except the high-temperature creep,” one company memo, dated July 12, 1999, stated.
” A July 21, 1999, memo notes that William Alderman of Powers Fasteners explained to designers that “all amine based fast-set epoxies do not meet the elevated temperature creep requirements by a significant margin,” and that fast-set epoxy has “ICBO acceptance for short-term loading due to seismic and wind events.”
” And an August 19, 1999, claims that the MHD acknowledged the creep limitations of fast-set epoxy, leading it to approve standard set epoxy for use in the tunnel.

The memos also indicate that Powers communicated this critical information – namely, the difference in creep characteristics between its fast-set and standard set epoxy to Newman Renner Colony, the company that supplied the suspended ceiling system components, including the epoxy, to the project.
Powers Not Allowed To Do Pull Tests
When some of the bolts began slipping soon after installation in 1999, Powers was called in to assess the problem.
In fact, contractors began installing ceiling anchors in July 1999 – days before Powers shipped a $1,287.60 special order for 120 units of its Power-Fast standard set epoxy, which was earmarked specifically for use in the ceiling, Schwartzman told FIN. She said fast-set epoxy was already on site for other applications, but was never intended for the ceiling anchors. At the time Powers had no reason to suspect fast-set epoxy has been used for the ceiling.
“If somebody special orders a product, you expect they”re going to use it,” Schwartzman noted.
Schwartzman provided FIN a copy of a October 21, 1999, field engineer report, written by Powers field engineer manager Stephen Rice, that documents Powers” efforts to diagnose the cause of the bolt slippage during construction.
When “slight movement” was detected in six 316 SS 5/8 inch threaded rod at 5 inch embedment about one week after installation in 1999, Rice arrived on site to assess the situation.
“We discussed possibly conducting destructive testing,” Rice noted in his report. “This was not received very well. Tearing up the concrete even in a discreet location would be unacceptable to some.”
Torque tests at the time revealed that “the anchor (nuts) were tightened to 120 lbs” instead of the 90 lbs of torque specified by Powers.
“This confirmed the suspicion that there were application problems,” Schwartzman told FIN.
Schwartzman emphasized that Rice was “denied the right to do pull tests” to determine the cause of slippage.
In a July 15, 2007, letter to the editor published by the Boston Globe, Powers president Jeffrey Powers stated “the NTSB made it clear that had (a pull) test been performed, the source of the problem could have been identified.
“Further, the test we were allowed to perform pointed solely to installation problems,” Jeffrey Powers wrote.
“Also, well before the Big Dig project team decided how to respond to the problem, Powers provided it with a report in which it was clearly stated that the fast-set epoxy was approved only for short-term loads.”
The NTSB later faulted project consultant Bechtel/Parson Brinckerhoff and Gannett Fleming for failing to conduct pull tests on the anchors. But federal investigators also criticized Powers Fasteners, citing the company’s “failure … to determine that the anchor displacement that was found … in 1999 was a result of anchor creep due to the use of the company”s Power-Fast Set epoxy.”
Powers responded strongly to that criticism.
“Powers did not know that Fast Set was used for the ceiling in place of the Standard Set epoxy, which we had every reason to believe, was used, based on what we were asked to supply,” the company stated. “Powers was asked by its distributor to supply a special order of Standard Set epoxy for use in the tunnel ceiling and that is exactly what we did.”
Schwartzman noted that the NTSB confirmed application errors by acknowledging that 19 of the 20 failed anchors “showed voids in epoxy,” demonstrating that “insufficient epoxy was applied to the bolts.” These voids reportedly reduced bolt load capacity by up to 40%. Plastic caps were also placed on every bolt during installation, reducing the weight-bearing capacity by another 10%.
“In essence, the NTSB concluded … that for 19 of the 20 failed bolts, the load bearing capacity had been cut in half,” Powers Fasteners stated.
Powers Cooperated with Investigation
Despite media reports to the contrary, Powers Fasteners “fully cooperated with the NTSB investigation, answering every question and providing every document requested,” Jeffrey Powers declared.
Massachusetts Attorney General Martha Coakley is still deciding whether to press criminal charges in connection with the accident, leaving a great deal of uncertainty for Powers Fasteners and the other 14 Big Dig contractors.
“This is a very serious matter,” Schwartzman noted.
The NTSB is currently making final revisions to the comprehensive Big Dig report, which should be finalized in the coming weeks. \ �2007 FastenerNews.com