[mamelukesabre]

If what you say is true, then the anchors would be like old fashioned lag bolts. that would be that last thing I would choose to hang these panels.


Here's my assumptions...admittedly based on ignorance of this tunnel:

The panels are apparently falling on people. This leads me to believe the panels are purely architectural in nature and contribute nothing in terms of the structural integrity of the tunnel itself...otherwise we would be reading of a tunnel collapse and people sealed off and trapped and running out of air...etc.


Without a schematic, I'm going to simplify everything and imagine these concrete panels are like a bigger version of drywall on your ceiling. Lets say they are 8" thick and supported at or near the corners by bolts. I would probably have specified brackets of some kind protruding from the back of the panel to be bolted to a steel framework of some kind above the panels. Actually, I would have preferred welded connections of some kind...but bolts it is, for whatever reason. If the bolts were in fact some kind of lag-like bolt...then length is indeed a serious factor...unless they are screwing into the side of a steel tube or I-beam or something. Then the thickness of the steel they are screwing into becomes the determining factor...not the length of the bolt. Also, if the bolts are machine type threaded into nuts on the otherside of a tube or plate then you need to consider the washer adequacy.

[John Valentine]

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.

[tuvals]

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