Posted on 07/11/2007 9:00:02 PM PDT by Ernest_at_the_Beach
Sure there are anchors that have the tensile strength on the anchor and on its embedment, but why not have a lipped channel, a "J" bolt embedded, or another item as I understood from an earlier thread that this was not embedded into rock, but instead anchored to sub-structure above.
What an amazing observation from someone who knows absoltely nothing about construction.
It’s just amazing how people with zero knowledge of construction can call standard construction practice ‘criminal’.
Boston...figures : )
Don’t disagree. This issue is largely due to politics, really. The put in the tunnel to meet the 1995 opening date, a political milestone. There was no forethough in the design for installation of the panels. Had they done so, a couple hundred $7 richmond anchors would have simply and efectively solved the design problem.
The magnitude of this project made everything dificult. There are hardly enough design engineers with the required competence to do everyday stuff, but when you are doing about the same amont of tunnel construction in a 10 mile area that is normally done across the country, the required manpower runs short, and stuff gets overlooked. Yeah, it’s a really bad oversight, but the initial designers did what was required, politically, to get the tunnel built and opened on schedule.
It may not have been rock, but roof slabs on these tunnels were 8' thick concrete, designed to survive a direct 747 crash, it's probably more competent than rock.
You’re way over my head now....
Can anyone say “root cause analysis”? A design that is prone to fail due to a single source of error like this is a rather poor one, in my opinion. Absolutely zero redundancy in the solution they chose. The whole thing was dependent on each and every bolt being epoxied into the ceiling holding fast. I’d hang my head in shame if I was the engineer that signed off on this design.
Was the glue made in China? THAT would not surprise me at all.
Romney’s Folly.
Well, anyone who works with the many types of epoxy resins, that's who. Read it in the West Systems manual, among other places. Talk to a guy who does bodywork on Corvettes, or repairs hull damage at any boat yard in Massachusetts.
This ain't rocket surgery.
Also, this is a possibly purposeful blind investigatory alley. Those panels were much too heavy for the fastening application.
If you bond an anchor 1” into concrete, the concrete will likely spall out in a cone shape, because you don’t develope the pullout over a big enough area.
Concrete strength is measured in pounds per square inch.
You need that cone big enough to carry the intended load, so you need to go deeper into the concrete to get that area of the cone of pressure large enough to carry the load. the deeper the anchor bolt, the larger the face of the failure plane, which is the surface of the concrete, or the flat part of the cone, as I try to describe it.
That seems to be the death knell for many people. They're a bunch of criminals with money that was stolen from the taxpayers.
Yeah, spread out the load over a bigger surface area.....I can understand that perfectly. Its calculating it that I won’t even attempt.
I’m a ‘tug on it’ type guy. I tug on it...”yep, that should hold”
Epoxy made in China?
With melamine filler?
/s (maybe)
They are used successfully in mining applications all the time. For the ignoratti here, there is epoxy and there is epoxy. using a formulation not designed for the application is the culprit.
Incredible, what next?? We'll probably hear how some phantom company with a P.O. Box can get nuclear certification from the government in weeks without background checks....
Bonging while bonding is great for first dates but lousy for building tunnels.
Kinda of like you trying to hold on to a sliver of soap in the shower and scratch at the same time.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.