So, What Happened?
Most local news outlets this morning are reporting the same information provided them by the Turnpike Authority.
From the Boston Globe:
A steel tieback that held the 40-foot ceiling section in place over Interstate 90 eastbound gave way, Authority Chairman Matthew Amorello said.
The Boston Herald:
[A State Trooper at the scene] said the 10-by-30 section that dropped was only half of the slab in that section of the tunnel. He said it appeared that iron securing the slab to the tunnel roof gave way.
CBS4Boston.com has a video up showing what looks to be the installation of these ceiling panels (see screengrab below). It appears the intent of this design was to create an air plenum at the ceiling for ventilation purposes. Think of it as a suspended acoustical tile ceiling in your office, only instead of lightweight ceiling tiles sitting in a aluminum grid, you've got 3-ton concrete slabs in their place, held in by steel anchors embedded into the concrete slab above.
I was unfamiliar with this particular design element until this morning when I started reading accounts of last night's fatal collapse. The first questions that came to mind were:
1. If the failure was caused by the steel hangers "giving way", what was the cause of that? Is there any evidence of water having leaked through the structural slab of the tunnel, which could have compromised the structural integrity of the steel anchors?
Naaahhh...couldn't be that. Everyone knows these tunnels are watertight as a frog's asshole.
2. What other explanations are there for these anchors failing the way it's being reported? Faulty materials? Methods? Design?
3. Now, you've got to ask yourself, which is more likely? That this was a fluke occurrence, and that all the other suspended panels in that section of tunnel are just fine? Or, that this failure was just the proverbial tip of the iceberg, and the whole ceiling could likely give way anytime now? If it's proven to be the former, good luck convincing all the people who used to drive through this tunnel of that fact.
3. Was there a qualified inspector overseeing this phase of the construction? Don't get me started going down that road again.
No doubt, these questions will be asked. Whether they're ever answered is another story altogether. One thing is certain, you can expect the Blame Game to hit never-before-seen levels of intensity over the next couple of months, if not years.