Design Flaw??? - Striper Talk Striped Bass Fishing, Surfcasting, Boating

BigFish · 07-15-2006, 12:12 AM

Alright! I have seen the video of the area where the panels collapsed......heard all the discussion and theory of why it happened! They are saying it was either the improper installation of the bolts which were epoxied into place? (Epoxied???? That sounds bad!) Or the epoxy was old and brittle????? (Old and brittle????Did they think this stuff was going to last forever and get younger and stronger???) I want to know when we are going to hear the phrase...."Design Flaw" used? Poor engineering in my opinion caused this tragic event! A guy from MIT did a demo on the news tonight showing what happened on a small scale model. Naturally what happened was the bolts supporting the panel from above center let go and the weight dispersement was sent to the supports on the side walls and these then gave way causing the panel to release and fall. I have several questions in regards to this design.

1. Why did they use cement slabs instead of a fiberglass panel? Fiberglass would offer soundproofing, easier installation and maintenence, support would have been a non issue.....not to mention perhaps more cost efficient if not in the beginning perhaps over time.

2. Why was the panel supported from above by a single bolt and cable which was drilled into the cement above and epoxied into place as opposed to having the bolt or a threaded rod installed permanently in the ceiling above via a metal plate perhaps when it was built?

3. The design shows support on either end via tie bars and a single cable support from above but the bulk of the weight of this slab/panel resides in its length and I have to wonder why there were no angle supports length wise between each panel as added support???

It just seems to me that the design of these panels is flawed in every way and these "brilliant" engineers who designed it used no common sense what so ever in the design of this portion of the tunnel and I can't wait to hear the words "Design Flaw" because that in reality is what is at issue here! Not the installation....not the epoxy...(though I think both may be suspect in their own right) it is the design which proved fatal....and unfortunately so!

Any thoughts?

Backbeach Jake · 07-15-2006, 06:42 AM

Personally, I can't believe that the engineers would try to hold tons and tons of concrete overhead with a few bolts set in epoxy. I wouldn't build a suspended ceiling like that for my kitchen, much less a major tunnel that under constant vibration and wet/dampness. There are many light weight and fireproof materials that could have been used.

Raven · 07-15-2006, 07:20 AM

just imagine if we had a tremmor
or an earthquake...
another natural disastor that
we're over due for...
during rush hour...

the fact that just one motorist
was killed is a freakin miracle

Swimmer · 07-15-2006, 08:39 AM

Cement panels are the only possible units that would work for the purpose that they are there. Why, because if a fire were to start underneath the panels if they were fiberglass or plastic the smoke would kill everyone or the melting plastic dropping on people as they run from a tunnel fire would cause catastrophic injuries also.

Epoxied bolts, right..........

Slipknot · 07-15-2006, 08:57 AM

1 - fiberglass = flammable and needs maintenence

2 - good question and one they will be regretting for a long long time, I guess the eggheads that came up with it have used the method before

don't know
sounds idiotic to epoxy screws in place, I mean moronic

oke:

3 - maybe there was no room above for that, who knows, you'd have to see the drawings and plans.

I thought the epoxied screws were in question Larry. I heard they were too short. Also I can't imagine an epoxy being strong enough to hold up that kind of weight. That whole project is flawed with all the cost cutting shortcuts taken because of the overpriced coruption. Too many problems they just passed over to deal with later, that's not right. Whoever hired incompetent contractors should be held responsible also. There seems to be plenty of blame to go around and now the finger pointing begins.

Bigcat · 07-15-2006, 09:06 AM

You see all the big signs on the hi-ways ,guess what is holding them up

sok · 07-17-2006, 07:24 PM

Quote:

Originally Posted by Swimmer

Cement panels are the only possible units that would work for the purpose that they are there. Why, because if a fire were to start underneath the panels if they were fiberglass or plastic the smoke would kill everyone or the melting plastic dropping on people as they run from a tunnel fire would cause catastrophic injuries also.

Epoxied bolts, right..........

I have been out of construction supply for a few years but I believe most sprayed fireproofing is a mix of fiberglass and ?
And part of the big dig was the construction of 7 massive vent buildings just for the tunnels. I delivered to #5,6 & 7.
2 in Southie and one at the airport.

My problem is 14+ BILLION dollars and the ceiling is held up with superglue? For lack of a better description.

Slipknot · 07-17-2006, 09:37 PM

Quote:

Originally Posted by Bigcat

You see all the big signs on the hi-ways ,guess what is holding them up

I like epoxy actually, it has it's purposes.
I just used it to glue in some threaded anchors today to a solid surface countertop to hold in an undermount sink, it will also be siliconed together and if it is filled with water and fails, I would be very surprised.
I also used epoxy to hold my entire boat together and it pulls the kids on a tube at 20 MPH just fine.

I heard some of those bolts did NOT even have any epoxy on them

quality control was lacking to say the least

likwid · 07-18-2006, 06:23 AM

epoxy = stronger than concrete.

atleast west systems is.

in the west newsletter a couple years ago they did tests in putting bolts into reinforced concrete using west....
the holes were oversized and either smooth or rough.

poured concrete into the holes.... bolt rips out easy
epoxy into smooth hole... bolt and epoxy plug rips out
epoxy into rough hole.... bolt epoxy and a fairly large chunk of the surrounding concrete rips out.

The Dad Fisherman · 07-18-2006, 07:11 AM

This morning on the news they were reporting that the designers of that System and the Architects were battling about this design back in 1999. Any Bets that the Designers have some connection to the Board that was in charge of the Big Dig and the Architects were "Pressured" into using that system.

Clogston29 · 07-18-2006, 08:22 AM

For point 2, I think its for waterproofing. If there was a bolt all the way through the concrete water would find its way between the bolt and the concrete and break down both the steel and concrete resulting in ceiling leaks and structural problems for both the hangers and the tunnel roof. I know that on bridges, codes do not allow for bolts to extend through the deck, I assume the code for tunnels is similar.

From what I've heard and seen on the news, it seams like there was either a flaw with the anchor system design or just poor installation. The factor of safety is very large, I want to say around 4, on tension hangers like that so something has to be really wrong for them to fail. No epoxy definately is something really wrong.

Saltheart · 07-18-2006, 02:25 PM

They should have used Elmers glue !

Its a shame when something that big and expensive isn't done well enough to last 100 years.We sound like the USSR during one of their 10 year plans. Sure they built the buildings but they started falling apart right away. we laughed at them. I'm sure the world is laughing at us now.

tattoobob · 07-21-2006, 08:36 PM

When the company showed up to install the ceiling fasteners they were told it was a job for the steel workes, they had no idea how this system worked and in drilling the holes for the fasteners they hit all kinds of rebar and cut the bolts short and epoxied them in. this is not how the system was designed to work. to hold a 3 ton slab of concrete you need a certain lenth bolt with the correct mix of epoxy. it all came down to the steel workers union saying it was there work and that no nonunion labor was to be used on that work site. the person who made that change should be hung

BigFish · 07-21-2006, 09:14 PM

Thats the best explanation I have heard to this point and it sounds about right!

Tagger · 07-23-2006, 08:05 AM

Controls.. there has to be Controls.. Having worked on building going up in that town, I've seen a clerk take samples from every concrete truck and pour them in a pipe and number them , and do slump test also . Then they lock all the pipe samples up in a gang box. Alot of times problems are created.. Heard egg heads changed bolt layout (placement).. Guess what ,there's re bar in that concrete every wich way and figured ahead of time for hangers . Its all speculation and finger pointing until the truth comes out . I do rehab now and wish I had a nickel for everytime I heard "Make it work".. No problem since my work is mainly cosmetic and ain't going to kill someone. The blame game..This "make it work mentality" has to go . "Make it work" is a good way to duck decision making responsibilty that may come back on you later. I know the game .. Not saying this happened there , I wasn't involved . Just seems to be the trend in construction . How about the hell with profit margine,, the hell with dead lines ."This has to be done right " Plus major construction company involved has a history of grossly underbidding work . What pressure do you think that creates .