Reply With QuoteTonight ...
There are four large beams placed in that rectangular depression located near the west end of the transit level , to the left of the center line. I find that an unusual piece of construction. Does anyone know what is going on there?
Tonight ...
They're elevator wells for the mezannine level to the subway.Originally Posted by SidewalkSuper
I think he meant horizontal ones. Looks like they just span the lower-level roadway to spread load of Hub columns that will go across.
Thank you! It's no wonder I couldn't figure them out. I was focused on finding some heavy load to be placed on the beams and never thought that they were compensating for reduced support from below.
Just wonderful. Last night, they installed 10 or 11 horizontal beams to the inside of the rib bases on the north side of the oculus. The first 5 or 6 may be part of one of the east end entrance levels. But the rest (#6-#11) make the rendering that I have been using as a reference for the future appearance of the east end totally useless, since it does not show anything to be built in this space. The so-called rendering I have been using shows the mezzanine walkway to the outside of the rib bases, and, until now, the steelwork supported that. Now, I have no idea what is going on.
There are some site diagrams posted around the forum which should help you get a feel for the construction.
Take a careful look at this:
http://brookfieldproperties.com/cont...mat-20115.html
You can see that the columns are set back and that the Calatrava arches extend from the mid and top level platforms defined by the new beams that you mentioned.
Thank you! That animation provides a much clearer picture of the supports than does the old picture I was using. I gather, since the weight of the rib is borne by the rib bases, that the bottom 25 feet or so of the ribs only serves to enhance the visual sweep of the ribs, but does not provide significant structural support to the main parts of the ribs. If I am correct, that would explain why the new beams are cantilevered from the rib bases and have no support at their distal ends.
Based on the video I made a diagram of how the finished product would look. No wonder the PATH hall had to be tied into Towers 2 and 3; this is some crazy stuff!
The brown is the steel they're welding in between the columns and Tower's 2 and Tower 3. The gray is the steel columns, the blue are the cantilevers they're putting up and the green is yet to come; the actual roof structure. Not only is it a member of the roof but it helps support the "wings" as well. Zen used to say that the best part of a building is its construction, and it's definitely proving to be so.
Nice graphic.
The arch piece with the little beams sticking out of it, that was lying near the slider, was installed next to the East wall of the hub.
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It's hard to make out from the aerial cam views but, when looking at the photo in the previous post and at various cam views, it appears that there is a marked grade change across the block where the Calatrava oculus will rise, moving downward both from east to west and north to south. The structure for the oculus appears to be constructed so the plane of the oculus will be flat.
Anyone know what that grade change across the plaza amounts to?
And how they are designing the plaza surrounding the oculus to deal with that? Are they simply gently sloping the plaza surface to meet / move away from the oculus, or are any stepped areas included?
Meanhwile, Tishman is seeking bids from contractors to procure & install stone for the interior of the Hub ...
WTC Transportation HUB Project
April 16, 2012
Invitation for Bid – BP #20 –Transit Hall Interior Stone
Tishman/Turner, A Joint Venture is soliciting sealed bids for Transit Hall Interior Stone on behalf of the Port Authority for the World Trade Center Transportation Hub Project. Sealed Bids will be received at the offices of Tishman/Turner, JV at 100 Broadway, New York, NY 10005, until the date and time listed below, after which they will be opened and publicly read aloud. A lump sum contract award will be made in writing to the responsible bidder with the lowest responsive bid. See below for further IFB information.
Scope Description: The furnishing and installation of approximately 225,000 square feet of preselected Interior Stone for the WTC Transportation Hub-Transit Hall, including the Grand Stairs and Concourse elevations. The contractor must purchase the pre-selected stone from the authorized supplier. The Contractor shall be responsible to coordinate the fabrication, delivery and installation of the Interior Stone, including all required detailing, shop drawings and submittals.
Approximate Range of Contract Value: $10,000,000 - $25,000,000
Approximate Contract Duration: 18 Months (Detail within Scope Documents)
Sealed Bid Opening: May 24, 2012 @ 3:00 PM
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