Skip to comments.Cheaper, faster path led to failure [ Big Dig ]
Posted on 12/24/2006 1:56:20 AM PST by SunkenCiv
Construction engineer John Tsikouras suspected that the salesmen were not telling him the whole story. The men from Newman Associates, a bolt distribution company, approached him in August 1999 and said they wanted his professional advice about a tunnel ceiling that was part of Boston's Big Dig. But Tsikouras said their questions seemed intended to get the Rhode Island engineer's approval rather than his expertise.
Would it be safe to hang the concrete ceiling from 7.5-inch-long bolts? No, Tsikouras said. What if the bolts were 5 inches long instead? "I can ask my mother that one," he replied: Even less safe, obviously. Then, the firm that designed the ceiling sent word through Newman that the ceiling would be far lighter than Tsikouras estimated. Would the bolts be strong enough then? Yes, Tsikouras replied, after making more calculations, "the bolts passed with flying colors."
(Excerpt) Read more at boston.com ...
I kind of liked it when I drove through.
I used to be in the nut and bolt biz.
When someone wants to shave points off a bid, that's the first place they look.
If that's cheap and fast, I'd hate to see expensive and slow.
Maybe it had to do with the depth to which it would be anchored.
The panels are not structural, but they create a plenum for the extraction of stale air - that's the rel reason they are needed. They are heavy because they are designed against flutter and movement.
The bolts are imbedded in epoxy filled drilled holes in concrete. The bolts are NOT (as I understand it) j-bolts or other typical embedded bolts.
The bolts are essentially glued into the concrete, and then the panels are hung from them.
This whole idea gives me serious pucker.
Secondly, this story is an attempt by the Boston Globe to shift the blame for the Big Dig fiasco to the engineers and the people who designed the structure.
The Globe does not want to implicate the Unions and the political corruption class in Mass (Democrats).
I lived in Boston in the pre-Big Dig era. Back then, they were estimating the cost of the project (this was in the late 1980's) and a friend of mine who worked for MIT Research Engineering (MITRE) told me the project would cost twenty fold that estimate because it would take place in Massachusetts - a sinkhole of corruption that even people on this board cannot fathom.
Boston and the state saw Federal Dollars gift wrapped in a bow when the project was approved.
Everyone got in line and had their hand out for "their share."
The Union bosses ruled this project from start to finish.
The cost overun on this project is a joke. It cost approximately 14.6 billion to build which puts it at ten times it's estimate. Add cutting corners, major blunders and even death and you get the message. The person who was the project overseer of this fiasco did the worst job imaginable. Had he worked for me he would have been on the outside looking in real quick. No accountability=you're fired! There is just no excuse for this except perhaps greed and the ripping off of the taxpayer. Oh, by the way 60% of the funding came from the federal government (you and me).
msnbc.msn.com/id/3769829/ - Boston's Big Dig finally opens to public is the article
I would have specified steel embedments in the concrete above...and steel embedments in the concrete panels and then specified that a certified welder weld the two together in the field. Then any exposed steel or welds would be covered by a concrete patching crew afterwards...If there were any at all.
Possibly more expensive but thats the way we did it at the company I worked for. Also, as an engineer, I would've had to review all drawings to ensure that the embedments in the tunnel in the one blue print matched up to the embedments in the other blu print for the panel castings.
Very tedious, but at least no one dies.
I would think that the time required to drill holes OVERHEAD in the field to glue the bolts into place would have ate up any savings they could possibly have realized by A: not designeing decent connections, B: not Taken time to place steel embedments and C: not checking for matching locations.
Have you ever personally drilled overhead into concrete??? Unless they had a special rig, it would take a full day for 1 guy to drill holes just for one panel!! Maybe even more time than that.
If someone had designed a connection at the plant I worked for that specified that much field work the prints would never have made it to the production floor. The autocad guys would have sent it right back to the engineer with notes about how stupid engineers are compared to regular working folks...except phrased politely of course.
this is the reason hyannis orcinus wins every election by 85% of the vote, now why lurch wins reelection is still a mystery.
Are you saying that state governments and their agents would commit fraud on the public by obviously manipulating and twisting safety results into an outrageous lie? That's amazing!
BTW, how is national healthcare coming along?
What they should have done is kept the elevated highway in place so that we would have twice the capacity we have now and maybe the tunnel portion could be reserved for those who are just passing through the city. Now that would make a difference.
Speaking of the elevated highway coming down, I thought we were going to have green parks after it was torn down with leafy trees and pedestrian-friendly paths leading to Fanueil Hall and the waterfront? Instead, they have spent two years pouring ugly, thick concrete slabs surrounded by thick wire mesh fences and it is still an absolute nightmare trying to be a pedestrian in that area.
I like that pic. I wish I still knew guys at the department of transportation. I'da sent that to them...they'da loved it.
Looks as if there is plenty of blame to go around. I don't see anyone mentioned in this article who is clean. Any time a project manager is trying to make a name for himself everyone else suffers. Some more than others as we now see. If bolting failed one time in any test I was involved in we would have found out why and corrected the problem. The idea of continuing when a large percentage failed is inviting disaster.
You can't be serious. It achieved it purpose magnificently. Put billions of dollars in the hands of Massachusetts politicians. Your traffic problems were never a consideration.
"the length of the bolt should not make any difference as far as i can tell."
So then size doesn't matter.
It is scary that with all the money spent on this, that somebody would feel the need to cut costs. That's Billion with a B, folks.
I do work at a Department of transportation (Mississippi). That looks like a job a District Maintenance paint-striping crew would do. I have had all kinds of problems with contractors, and my share of arguments and Mexican standoffs with them, but even the worst private contractor is far better at road-building than your average Highway Department crew.
I am so proud to be a member of this forum!
Would you say that one and a half times the bolt diameter would suffice for embedment in concrete with epoxy bonding?
Of couse not. Obviously, bolt length is a factor in such a design.
All the stress that the bolt is holding has to go thru the first "length" of 1.5 * dia. this is comparable to the weakest link in a chain. If the first length can not do the job, you have the wrong bolt. It really does not matter if the bolt was one mile long.
"Cheaper, faster path led to failure [ Big Dig ]"
It seems like every single new weapon system program manager that shows up at the pentagon has memorized the mantra "Better, Faster, Cheaper." And we all know how famously some of those programs have succeeded.
One wag in my office has a triangle on his whiteboard with each side labelled better, faster, and cheaper. His tagline says" You can pick any two sides; some programs give you only one."
You can do it right, or you can do it over.
LOL... the original explanation of the bolting apparatus they gave to the press sounded like it was for the absurdity of 'asthetics'. But this proves once again that careers... and money... beat out a human life every time.
There are people at all three levels, local, state and federal, who need to be held to account for this.
US taxpayers should get a refund from the State of Massasschusetts. How much did the federal guvment spend on this thing, Kennedy's Hole, $15 billion?
According to your reasoning then, a one inch bolt embedded one and one half inches into concrete would be capable of holding the full tensile strength of the bolt.
Were you on the Big Dig design team?
"I would have specified steel embedments in the concrete above...and steel embedments in the concrete panels and then specified that a certified welder weld the two together in the field."
How much field experience do you have?
This system has been used for years to anchor heavy equipment to FLOORS where there is relatively little tensile load on the joint and where you are assured that the epoxy is well contained while it sets up.
This would probably be the worst application for this type of a fastener in that a full bond could not be assured particularly given the field installation methods.
I cannot say what the design specification was in this application, but I would not feel comfortable with less than a 5X margin of safety (but then my supervisors have always deemed me to be conservative). Should one of them fail, the adjacent fasteners must take up the load. But given your description of the panel, it is more likely that several of the fasteners failed simultaneously over a period of time. I.e., a poorly designed application for a marginally installed product.
The failure was undoubtedly NOT in the bolt, rather in the epoxy attachment to the concrete. The 1.5X rule is valid for a threaded fastener into similar materials (steel into steel), but in this application, it does not apply.
You really need much more than 1.5X engagement when using epoxy to secure the fastener, and the bonding operation is very depentent on the quality of the application (operator dependent). Most critical applications require extensive validation testing to assure the bond process is peformed properly.
Do you comprehend how a chain is as strong as it's weakest link?
Have you ever thought about why nuts are only so thick? Bolts do their work in the first threads, once you are in the proper amount, you do not gain any more strength.
And to answer your stupid question, no I do not have anything to do with the Big Dig, except pay taxes.
From what I heard, the workers faild to clean out the holes after they were drilled, so the epoxy bonded to the dust.
"From what I heard, the workers faild to clean out the holes after they were drilled, so the epoxy bonded to the dust."
Not an unreasonable observation, but even with a clean hole, how do you assure a 100% bond in an overhead hole?
I'm only happy that it was not my product in that application.
Not cheaply. You would have to cure the epoxy under pressure.
I would be interested to know if the whole epoxy plug pulled out of if the threads in the plastic pulled out of the hole. The issue here is not the length of the bolt but the strength of the plastic threads and the strength of the glue to the concrete and dirt. Hind sight being 20/20 I think Studs should of been placed in the concrete.
You seem unable to comprehend what is being discussed regarding the bolt failure. The stupidity isn't mine.
And won't be.
You asked if I was a Big Dig engineer. That was a stupid question. Only a stupid person would think that someone involved with the Big Dig would be disusing the issue on a forum such as this. That is why you asked the stupid question. Tell me why it was a smart question, if you believe it was not a stupid question, then I will revise my opinion of you being a stupid person.
My goodness, buried in the article's lies is a little of the truth!