Well, maybe not good vibrations, but vibrations nonetheless. According to The Post, shop owners along Second Ave. have found yet another aspect of the Second Ave. Subway construction project that irks them. This time, vibrations from the construction have shaken up the bricks in the surrounding buildings. Due to the dangers of falling bricks, the MTA has constructed sidewalk scaffolding, and owners say their businesses are suffering. The agency, however, says that the vibrations are not weak enough to loosen the bricks and that the buildings were structurally weak before the construction. And so it goes.
Second Ave. business picking up good vibrations
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Couldn’t they have just done cut-and-cover and avoided all this nonsense…?
Considering how long utility relocation has taken for the TBM launch box alone, can you imagine how long it would have taken to do for the length of Phase I? Part of the point of doing the tunneling with a TBM instead of cut-and-cover is avoiding having to move miles of infrastructure.
What they’re doing at the current construction site is cut and cover. They have to construct the launch box using cut and cover techniques before they can put the tunnel boring machine in the ground. They’re just now putting in the second half of the panels that will provide the temporary street surface during the construction, and are starting the deep excavation of the launch box at the south end of the construction zone. With cut and cover, the sort of inconvenience that we’re seeing between 91st and 96th streets would be felt all along the length of the route. Instead, it’ll only happen in a few areas.
It’s happening in the blocks near 72nd and 86th as well. Thus the major intersections of the East Side all have cut and cover anyway.
They need to use cut and cover to excavate for the stations. TBM isn’t going to provide the space needed for them. They are minimizing cut-and-cover to locations where they absolutely need it, mainly because TBM is the faster and more economical approach.
Maybe I’m off-base, but I was just getting the sense that they’re using this tunnel-boring method at what must be a vastly greater expenditure over the tried-and-true cut-and-cover method that worked just fine for… every other subway line in Manhattan, and for what? To keep businesses on 2nd Avenue happy? Yeah, that’s important, but at what cost? In the old days this line would have already been done by now.
Tunnel Boring Machines are actually more economically feasible in these modern times. Labor is not as cheap in NYC as it used to be. Also, they never would have gotten through the environmental impact study phase had they gone with cut and cover. The dust problems alone from cut and cover would have been a nightmare. In addition, back in the day, the city had a lot more lax policies on fire department access, garbage collection and such. Also, back in the day, the city government didn’t really care about anyone. Tammany Hall was in it for themselves, which occasionally meant that infrastructure got built (construction projects provide so many interesting opportunities for graft).
The hammering and drilling for the secant pile walls is what is causing these ‘supposed’ structurally deficient buildings to have issues. These would go on regardless.
Tunnel Boring Machines are a tried a true method in NYC and around the world. They dug the Channel Tunnel and they’re digging the Gothard Base Tunnel through the entire base of the Alps from Italy to Switzerland. They’ve been using TBMs to dig the NYC DEP Water Tunnel #3 for quite sometime. They’re using them quite successfully on the East Side Access project right now. So, its not an expensive untested technology or something. The TBMs are faster at digging through the various hard rocks of Manhattan better than drill and blast or cut and cover. If it were cut and cover there would be blasting going on at the surface. Imagine the complaining and issues if that were happening.
Its not surprising to me that there are structural problems with some of these buildings. Maintenance isn’t usually the highest priority of most landlords lists (you’re lucky if it makes the top 50). The question really is who is responsible for paying for the repairs.