Big Dig Firm Pleads Guilty to Supplying Substandard Concrete

hi all

This story demonstrates what is wrong with the media, although I expect more from a technical publication. The story merges two separate issues on the big dig into one very confusing story. First, Aggregate Industries did provide over 5,700 out of specification concrete loads (10-12 cyds) to the Big Dig through the use of doctored loads of out of spec concrete. The rejected or out of spec concrete was reworked with additives, additional water and in some cases supplemented with new mix to make it appear fresh an in spec and a new batch slip was fabricated for the load, hence the fraud committed by 6 employees. Second, the I-90 ceiling collapse had nothing to do with the concrete issue above. The ceiling collapse has been attributed to the inappropriate use of Powers Fasteners, Power Fast Epoxy. The cause of the accident as determined by NTSB (full report on line and good reading) was the use of the Fast Set version of the Power Fast Epoxy. Although Powers sold this product as simply a faster cure/gel time version of their Standard Set product, it had completely different creep attributes under sustained loads. The Fast Set version had severe creep (deformation over time) characteristics, which was known by Powers as early as 1995, but they failed to modify their brochures or published engineering data and they simply continued to sell it as one product with two cure/gel time versions. The product, Power Fast Epoxy (without version distinction) was approved for use under the confusing documentation or lack of version distinction from the manufacturer. Even when there were early installation failures and Powers field personnel witnessed the installation and product use they did not point out the creep problems with Fast Set. In this case, the proximate cause of the collapse is clear; the Powers Fasteners knew its product characteristics, witnessed its application first hand and failed to act on this information to avert a later collapse. The only other problem is the lack of an in-service inspection program from the owner which may have caught the problem early enough to prevent the collapse.

The entire Talking Points article is as defective as the concrete and the epoxy. It uses a hedline about the concrete without any in depth explanation of the case and then goes into the epoxy failure with a rambling typical of a technophobic style of journalism while the subject demands a competent analysis. Who was the engineer approving plans for a project where such unusual engineering practice was used that could have a serious failure mode. The fault belongs to the civil engineering profession alone. They know politicians and contractors are crooks so the engineers should have established a foolproof system of qualifying materials and practice.

I live in the Northeast, but I have to admit I haven't been following this story very closely, mostly because I suspect that whatever real culprits there may be will get off with no penalties because they know somebody in the Massachussetts State Government. Most State Governments very piously throw rocks at 'Big Business,' but since they make the rules, are usually far more corrupt. Be that as it may, the reason I'm making this post is to ask how it was determined that there was criminal negligence, and not simply incompetence. For that matter, how did they determine that it was a contractor at fault? I wonder if it ever occurred to anybody that a bureaucrat in State Government could have meddled and insisted that things be done this way? I worked for Federal Government contractors long enough to know that this sort of thing is a common occurrence at the Federal level, so I would be surprised were it not also that way at the State Level. But of course, we All Know that Evil Big Business is at fault, so let's not go looking anyplace but there (loses interest in bogus politics once more) ...