Engineering Materials

Engineering materials is a discussion led by Design News Contributing Materials Editor Doug Smock on important new developments and applications that affect mechanical design. Metals covered include all types of steel and nonferrous metals, in all shapes. Resins covered include nylons, polycarbonates, polysulfides, polyimides, and polybutylene terephthalate (PBT). Other materials covered include ceramics and rubber. Topics covered include materials enhancement, new applications, process technology, tooling, sustainability, and economic issues. Posts will include latest news from global events such as K 2007, the Alliance of Plastics Processors Annual Conference, the National Plastics Exposition, and the annual technical conference (ANTEC) of the Society of Plastics Engineers.

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Monday, July 30, 2007

Big Dig Epoxy: We Should Have Listened to Pogo

A close look at the epoxy failure in Boston’s Big Dig shows how even the best engineering intentions can go wildly awry because of poor communications through an extended supply chain. It was widely know that fast-setting epoxy was not capable of holding sustained loads over time. That issue is now summed up by the National Transportation Safety Board as the “creep” problem. A Massachusetts highway engineer, Clement Fung, made it clear from the git-go that the fast-setting epoxy would not be approved for use in the I-90 connector tunnel ceiling because it lacked the requisite approvals. To make a long story short, the material, however, later was approved for use in non-demanding applications, such as putting tiles on walls of the tunnel. The quick-setting epoxy arrived on the work site first. Workers—apparently completely unaware of the difference—used the quick-setting materials for the ceiling.

Here’s a wild kicker: All of this, starting with request for approval to install, took place within less than a month.

Here’s another wild kicker: The total value of the epoxy materials involved was less than $1,300.

The complete communications breakdown is due at least in part to the supply chain involved. The epoxy was sold at the work site by a salesman for a local distributor of products packaged and developed by Powers Fasteners of New York. Powers Fasteners had hired a prestigious engineering firm (Simpson, Gumpertz & Heger) to solicit the necessary approvals from Massachusetts highway engineers.

According to a published report, the epoxy salesman involved plead the Fifth amendment 27 times when questioned by NTSB investigators last spring.

So who was responsible to make sure the right information got to the work site? The NTSB said it was Powers Fasteners’ responsibility. Any of you who buy from distributors, however, know that the OEM may or may not be available to supply on-the-job training, particularly for such a small order. With hindsight, of course, things would have been different.

There are still puzzling issues remaining: 1) Where else was the fast-setting epoxy used? 2) To what extent should epoxy of any type be used for long-term loads, such as holding ceiling bolts in tunnels? 3) What communications protocols should be implemented in the future to make sure such stunning problems do not occur again?

We are in a national frenzy right now about potential attacks by terrorists. But as the great man Pogo once said, “We have met the enemy... and he is us"

Related entries in: Design News |

(Add your comments)

at 7/30/2007 1:52:43 PM, Joe Eng said:
Good story but an important fact is missed. MHD was not in charge of the Big Dig. The Mass Turnpike Authority had ownership and authority. MHD approval only covered MHD projects. The Powers people never told MTA/Big Dig Project personnel that its Fast Set material had a creep problem. Clem Fung, MHD said he wouldn''t approve it for "MHD" work. Now we know why Powers rep plead the 5th.

at 7/31/2007 4:41:05 AM, DON DRISCOLL said:
Powers gave all the information about its epoxies to the Mass High Dept., the suppliers of the panels, designers, engineers, and the any agency involved in the installation of the panels. The powers company provided all memos dating back to 1999 about the proper epoxy to use and how it was to be installed. They were denied doing pull tests and destruction tests on the anchors. The salesman who took the fifth was NOT a Powers rep. Powers fully cooperated with the NTSB investigation and provided every document that was asked for. The blame stands with the supplier, and contractors who installed the anchor rods wrong. If the proper epoxy had been used and installed properly the accident would of never taken place. The panels that were used were also heavier than what was on the original design. If the managers and state were not in a big hurry to get the job done ahead of schedule and proper tests had been allowed the failures would of been discovered before the accident. Get all the facts before you put your spin on the truth Joe.

at 7/31/2007 11:05:54 AM, Joe Eng said:
Don, Let me un-spin the truth for you. Read carefully, Mass Highway, (MHD) did not have jurisdiction over the Big Dig Project, the information sent to MHD was for statewide MHD project use. Powers’ proposed ultimate (destructive) pull test gives information on ultimate capacity not long term creep characteristics. Jack Armor, Powers Fasteners took the 5th, 29 times and failed to answer a single question, he wouldn’t even verify who he worked for, not the action of a company representative with nothing to hide. A Powers Engineer visited the site with Armor in October 1999 and said that the problems were installation related and proposed a test that wouldn’t detect a creep problem. The panels were heavier than the Ted Williams Tunnel, but the heavier panels were the basis of the I-90 Ceiling as bid and as built design, no change here, you’re struggling with the facts again. The only tests proposed by Powers were ultimate pull tests and torque tests and both were completely discredited by NTSB and the lab reports. The NTSB report is complete the documents are all on their website and in the public docket FTP site. Don, ensure you have a good command of the facts before you weave your own tale. You should make sure your information coordinates with Powers’ Press Release, letter to the editor and latest information provided the press last week.

at 8/8/2007 2:57:29 PM, Brian C said:
Whoever came up with installing concrete panels overhead in the first place, should be blamed. Who in their RIGHT MIND would suspend anything that heavy, over anyplace that people pass thru? Something like that should be either "thru bolted", or not put up at all.

at 8/8/2007 4:37:00 PM, interested said:
ok, so Powers may have submitted info to Mass Hwy Dept. and, ok, Joe Eng is right that Mass Hwy was not the manager of the Big Dig in 1999. but here's the question that no one is asking and Powers isn't answering: why didn't Powers change its product literature to clearly state that Fast-set epoxy should not be used in overhead applications if it knew in 1999 that it shouldn't? Powers didn't add that language to its product literature until May of 2007. Why??

at 8/11/2007 8:28:51 AM, Joe Eng said:
PM, thats a very good question does Don have the answer?

at 7/2/2008 5:20:45 PM, All wrong said:
Modern continetal has just been charged with the crime of using the wrong epoxy, Knowing about it and Installing it wrong anyway.

at 7/2/2008 7:34:03 PM, Hello said:
Research This? The sale of standard set epoxy had arrived A day after the panels were being installed. There has been the question of the distributor never selling and delivering fast set epoxy to the job. Question, what was used? Also If you reaserched more You woud find out the ditributor plead the 5th not the manufacturer.

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