Ted Williams Tunnel

[Marc]

there's no way what you're saying happened could happen.

At least, not without large sums of money and possible mutual oral gratification.

Naturally.






Ok, so I go for the little knife, and you go for the jugular. If he moves I'll give him a very serious scratch that may require stitches.

 

[ctenidae]

If he moves I'll give him a very serious scratch that may require stitches.

Maybe not stitches, but I guarantee he'll need some Bactine and possibly a peice of gauze when we're done with him! That'll learn him to draw plates with only four bolts! Did you notice the other plate? it only has two, for chrissakes. That's going to earn him a nasty Indian rub.

 

[hiroto]

Typically this sort of thing happens when a contracter with no engineering background is attempting to cut costs by reducing factors of safety in the design without consulting the engineers first.

Or, it could be engineer pressured by management to cut cost reduced the safety
margin, thinking the margin was still suffice based on the engineering data from the
glue manufacture whoes data was based on much better controlled process.
Note that in the article the glue manufacture is suspecting epoxy was not properly mixed.

I take back my "Amazing... " comment. It is a tough call if the design should have
considered the possiblity of the bonding failure, and it is not obvious when this bolts
test with 8/50 failure was done. You cannot build anything if you don't trust the engineering data of the materials you are using to a certain degree.

It could well be that this method is used reliably widely and the contractor did
amazingly bad job of applying it, or the engineering data of the glue was way too
optimistic, not considering the level of variation expected on actual construction site.

 

[ctenidae]

If they'd only used JB Weld instead of some fancy-schmancy epoxy, it would have been fine. Really, they should have just built the whole thing from JB Weld.

 

[ChileMass]

If they'd only used JB Weld instead of some fancy-schmancy epoxy, it would have been fine. Really, they should have just built the whole thing from JB Weld.

Or that Gorilla Glue they sell in the checkout lane at Home Depot........I hear it's the world's strongest......

 

[ctenidae]

Ooh, forgot about the Gorilla Glue.

 

[Marc]

Ooh, forgot about the Gorilla Glue.

I heard they've already got duct tape crews patching more tunnel leaks. They should've built the whole damn tunnel from duct tape.

 

[ctenidae]

If it moves and shouldn't, use duck tape.
If it doesn't move and should, use WD-40.

Go here: www.marketwatch.com
Enter the symbol WDFC in the "Get Quote" box at the top.
Click on "Profile" under the company name
Read teh "Company Information"

Greatest. Business. Synopsis. Ever.

 

[smitty77]

Or that Gorilla Glue they sell in the checkout lane at Home Depot........I hear it's the world's strongest......

On a side note, from Workbench Magazine August 2006 issue:

"Gorilla Glue: Dogs Love It!

I like Gorilla Glue because it works. Dogs like because it smells like peanuts. Or maple syrup. Or peanuts covered in maple syrup. Whatever. They like the smell of it, and they eat it. And then it expands into something the size of a Nerf football that has to be surgically removed.

There are at least two confirmed cases of this happening, and both dogs survived. Gorilla Glue is aware of the problem and has changed the labeling to warn specifically against animal contact. Our advice is to continue using Gorilla Glue, but take care to store it as cautiously as other household chemicals."

--- End of Side note.
I'm a civil engineer, though I have zero experience with structures so I'll reserve my own semi-professional opinions on design. I'll just add that I agree with Mark in that we don't know what the design requirements and assumed safety factors were to begin with, and cannot really compute without some advanced software. That being said, has anyone heard if the failure was due in part to the weight of the concrete panels? I'll elaborate:

The major component in concrete is the aggregate which is commonly sand and stone, but it can be anything, including lava rock (which is less dense than quarried stone) or even tiny glass beads. Natually occurring materials such as stone can have a variation in density. This density can be measured, but it is a fairly time consuming process (the traditional method takes two days) and therefore is not checked as often. The problem lies in the fact that conrete mixes are designed volumetrically, based on these density values, and if the density changes during production the resulting conrete ceiling panel can be heavier or lighter than originally anticipated. I've heard the 3 ton number bandied about, but does anyone know if this is the true measured weight of the panel, or just the design value? If the panel actually weighs 4 tons, and some of the epoxy was poorly applied, a catastrophic failure is more certain. One would think each precast panel would be weighed before it was put into service, but with this project any shortcut seems like a possibility.

Just my two cents.
Smitty

 

[smitty77]

Or, it could be engineer pressured by management to cut cost reduced the safety
margin, thinking the margin was still suffice based on the engineering data from the
glue manufacture whoes data was based on much better controlled process.
Note that in the article the glue manufacture is suspecting epoxy was not properly mixed.

Although all anyone hears in the news is how contractor XYZ tried to screw the state out of millions, the reality is there are many reputable companies out there trying to produce a safe and reliable product for the state. What you don't hear is how inept and retarded state agencies like MassPike and MassHighway are. In Massachusetts, there is a lot of handholding going on when it comes to construction practices and methods. I'll explain:

In QC testing, there are two basics types of specifications. Method Specs and End-result Specs, as quoted from the New England Transportation Technician Certification Program's Quality Assurance Technologist Course manual.

Method Specifications = "Specifications that require the Contractor to produce and place a product using specified materials in definite proportions and specific types of equipment and methods under the direction of the Agency."

End-Result Specifications = "Specifications that require the Contractor to take the entire responsibility for producing and placing a product. The Agency's responsibility is to either accept or reject the final product or to apply a pay adjustment commensurate with the degree of compliance with the specifications."

My guess, based on past interactions with the state DOT agency, is that those panels were placed under a method spec where it is likely that the state specified the design of the attachment as well as the specific size and number of bolts, rods, and brackets, as well as the specific type of epoxy. If the state requires the contractor to construct the ceiling in such a way, and the contractor complies, and the state accepts the work, how can the contractor be held liable? Of course if the contractor did not use the specified materials then all bets are off. Just don't automatically assume the contractor or some private engineering firm did the design work. It could very well have come straight from some state-run office in Boston.

Sorry its long, but it really goes up my ass when people are quick to blame the engineer or the contractor, and the state agency gets a free pass. Of course hiroto your statement still applies for a state agency engineer and the associated directives from management, it just had an anti-contractor tone to it (IMHO), like a lot of the media reports. Just pointing out the folks at MassPike could very well be held crimially responsible for all of this.
Smitty

 

[Vortex]

Smitty 77. Great post! Well thought out. I believe you have a strong field knowledge also.