From the latest PA Progress Report, March 2011 ...
ONGOING COORDINATION TO BUILD THE VEHICULAR SECURITY CENTER
www.wtcprogress.com
While much of the above-grade progress at the World Trade Center (WTC) site is becoming obvious to throngs of tour- ists, daily commuters, and even the nation, the Port Au- thority and its contractors are also diligently working to create the below-grade Vehicular Security Center, or VSC.
Scheduled to open at the end of 2013, the VSC will play an extremely im- portant role in the safety and security of the WTC site. It will be used to screen buses, trucks and cars entering the WTC site and its wide array of facilities—one aspect of a comprehensive WTC-area police security plan.
Coordinating the construction of major office buildings, a transportation hub, a national memorial and all the significant underground infrastruc- ture required on this complex 16-acre site (with two active train systems running through it every day), is no simple task. Among the many chal- lenges of a construction site of this size and complexity is the coordination between all stakeholders, including other projects and nearby residents and businesses. The Port Authority has a comprehensive logistics plan of the various activities for each project and meets regularly with internal project managers, various government agencies, and adjacent property owners. The Port Authority also provides for and encourages an ongoing dialogue to adjacent properties, and attempts to address any issues or concerns as quickly and efficiently as possible.
In the case of the VSC, coordination with nearby properties such as 90 West Street—a residential building located directly adjacent to the VSC construction site—has occurred since the beginning of construction and will continue into the future as the Port Authority continues its early-ac- tion construction activities in the southwest corner of the WTC site. Regu- lar meetings and coordination also occurs with the National September 11 Memorial and Museum—under construction just to the north of the VSC site; 130 Cedar Street—an adjacent hotel; and the Lower Manhattan Development Corporation—tasked with the deconstruction of the 130 Liberty Street building, which was partially located on the VSC site. In ad- dition, other stakeholders include a number of government agencies with a role in the project or involvement in nearby efforts to revitalize Lower Manhattan.
An example of this close coordination during the VSC project occurred during the construction of the “bathtub” walls, a series of concrete panels necessary to isolate the excavated area from the surrounding soil and to prevent water infiltration. These panels are 22 feet wide, 3 feet thick, and 65 feet deep. Because of its proximity to the New York State Department of Transportation’s Route 9A reconstruction project, weekly coordination was necessary and is still part of the project’s continual momentum. The logistics of utilizing 160 trucks per day in order to haul away more than 70,000 cubic yards of soil from the site also poses coordination challenges for the construction of the VSC, as the main thoroughfare for this activity is one of the most heavily-used highways in the region.
Other initiatives to facilitate the construction of the WTC site within the context of a growing downtown residential population include mitigation efforts to lessen construction equipment noise. The Port Authority uti- lizes state-of-the-art equipment to excavate, drill and erect the site in the quickest method possible, and requires contractors to retrofit equipment in order to mitigate noise in the surrounding community. When con- trolled blasting is necessary, the Port Authority will alert nearby proper- ties in advance and will create specific notices to complement the weekly newsletters and various print materials as part of the ongoing efforts from the Port Authority.
A view from Phase 2 of the VSC as we begin to Jet Grout under the now gone Deutsche Bank building.
A pond which we are filling to equalize water pressure inside the basement walls of the old DB building before drilling down.
Sorry if it has been covered, but did they take out the entire basement of the DB building? I don't know how many floors were underground. Isn't there some huge vault down there?
And fantastic insider shots and info! Thanks!
The lowest basement level in DB was at elevation 278' (approx 30' below the grade of the surrounding streets; so not overly deep. The pond that you see above is 16' deep, filling that 278' basement level. Future construction will be going much deeper than that...another 50' in places.
The CAT excavator in the foreground of the above picture is beginning to chop down the rock to lower elevation in Phase 1 of the project...another 40' to go below his tracks. The old Liberty St bridge can be seen above the site.
Wow. The bathtub wall is amazing. Just a few months ago we were watching them place them inside the ground, and to watch the site get excavated this far...it's just amazing.
http://news.yahoo.com/s/yblog_dnainfo/green-lake-replaces-deutsche-bank-building
An interesting article on the lake I mentioned above...they don't have the reasons totally correct as to why the lake was created but the gist of it is there. It's leaking by the way....and has dropped 5ft over the past week so it will be a very temporary sight in Lower Manhattan!
Last edited by IrishInNYC; April 15th, 2011 at 02:59 PM.
Question: Why isn't the groundwater pressure a problem on the southern section of the DB foundation?
THe Deutsche Bank building rested on landfill, which in turn sits on a layer of groundwater
"The building provided opposite forces [to counteract the upward pressure]," Brathwaite told Community Board 1 Monday. "Now that the building is no longer there, we have to [create] opposite forces with water."
Huh? what is this? Yosemite Park? so the One train goes through water?
I can answer both of the above questions simultaneously:
The more correct reason why the "lake" was filled was due to the fact we are puncturing the existing DB pressure slab in order to create the new, extended bathtub. The danger with that, is the slab under DB was at elevation 278', normal watertable is at around 294' (only 10' or so below street level so yes, the 1/9 subway box is almost entirely submerged below the watertable). If we drilled through the slab, without raising the water table inside the DB footprint to 294', there was a real danger of water rushing up through the hole and causing settling underneath the subway box along Greenwich St.
The simple reason the lake is only on the north end is because there was already a hole there...it's important to not just think of it as only the lake, the water is at that level throughtout the entire DB site, infiltrating through the material we are working on to within a couple of feet below the machinary.
Feel free to ask any more questions, I'm happy to answer them.
Last edited by IrishInNYC; April 15th, 2011 at 02:40 PM.
Thanks. That clears it up.Originally Posted by IrishInNYC
Will the park above the VSC be at the ground level of West Street or will one have to ascend steps from West Street to enter it.
Last edited by londonlawyer; April 19th, 2011 at 08:18 AM.
There was some discussion a while back in this thread about the wall of the VSC that will be along West Street. No details of this area have been released, so where steps might be is a mystery.
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