NEW YORK | 200 Greenwich - 2 WTC | 1,226 FT | 55 FLOORS

[Big Towers]

No, No, I know that the foundations are suppose to have that shape, because that's what the building's shape is if you look directly down from the top.

I'm talking about that edge on the southwest corner of the concrete core. As you can see from pictures and webcam images, the southwest corner makes the entire foundation walls not-symetrical, like they are shown on wtc.com floor/ground plans.

I drew a picture to demonstate what I'm trying to say:



As you can see, I circled the area where the foundation walls are bent.

[Obey]

I don't think they are bent in the first place.

[STR]

There won't be any elevators in that part of the building anyway. Not that far down, nor in that particular corner. All of the passenger elevators in 2WTC are arranged in a cruciform shape along the two central corridors of the building.

The core itself will change shape nearly a dozen times on the way to the roof. This particular shape will hold until the ground floor.

[uakoops]

It's hard to see b/c the drawing is so small, but it looks like only the inside edge of the core is bent, while the outside is straight. Therefore it seems that the core wall will actually be extra-thick right at that corner. In some of the older pictures at wtc.com you can see the extra rebar in that area, particularly this one: http://www.wtc.com/media/images/d/14_59_2011_01_04-Tower-2.jpg

I wonder why they need the extra strength in that area.

I also noticed that the south wall of the core has one row of rock anchors, while the north wall has 2 rows.
http://www.wtc.com/media/images/d/14_59_2010_10_04-2WTC---Credit-Joe-Woolhead.JPG

[scalziand]

@davidinasia:

I can't answer your concrete question, but I can answer your question about the pegs in the columns. They are called studs, and they are for connecting the steel with the concrete to make it act as a single structural unit. However, this does not necessarily mean that the rebar is directly attached to the studs.

[davidinasia]

Originally Posted by scalziand

@davidinasia:

I can't answer your concrete question, but I can answer your question about the pegs in the columns. They are called studs, and they are for connecting the steel with the concrete to make it act as a single structural unit. However, this does not necessarily mean that the rebar is directly attached to the studs.

Thanks, I figured it would be something like that.

[OneWorldTradeCenter]

The construction site reminds me at those of One WTC in 2008.

[Patapsco]

Taken March 14, 2011

[MadGnome]

You never know. They're competing for inches so fiercly down there they might be cutting corners (never used that in a literal sense before) just to make room for something else in that spot.

[NYguy]

Great comparison shot...

rbenkovitz

[Obey]

That's definitely the best shot to show the old WTC site. We should get more from that angle.

[Zensteeldude]

Originally Posted by MadGnome

You never know. They're competing for inches so fiercly down there they might be cutting corners (never used that in a literal sense before) just to make room for something else in that spot.

As uakoops said, it is actually a thicking of the core wall. What we can see now is the inside form for that area of the wall.

[Zensteeldude]

Originally Posted by uakoops

.

I also noticed that the south wall of the core has one row of rock anchors, while the north wall has 2 rows.
http://www.wtc.com/media/images/d/14_59_2010_10_04-2WTC---Credit-Joe-Woolhead.JPG

That has to do with prevailing winds. The prevailing wind is from the west northwest. I'm sure that there are other factors, like Towers One and 7.

[uakoops]

Thanks for the explanation Zen. But wouldn't the building would be most exposed to southwest winds because of all the open space there from the memorial plaza?

And what happens if they design a building for a certain wind direction and then later they build another highrise right next to it?

[Zensteeldude]

The loads are calculated over the hight of the building. (Tower 2 is much taller than most of the surrounding structures and that exposure is factored into the design.)

Also note that the building is over designed. In the case of Tower 2 the design factor is probably around 1.8. Or 1.8 times the expected forces. Any future construction near the tower would not be an issue.

[MadGnome]

I didn't read uakoops extra rebar post well enough. It's not my fault. I have an extra copy of the lazy gene.

Originally Posted by uakoops

Thanks for the explanation Zen. But wouldn't the building would be most exposed to southwest winds because of all the open space there from the memorial plaza?

And what happens if they design a building for a certain wind direction and then later they build another highrise right next to it?

I'm guessing the base windload from wind on the semi-protected bottom half of the tower isn't too significant to the load from wind on the unprotected top part.
Putting other buildings nearby should just reduce the windload on the first building. Nothing wrong with being too strong in one direction.

[Big Towers]

New perimeter steel columns have arrived for the southwest portion of the foundation. I'm guessing they're being installed as we speak.

[Zensteeldude]

It looks like some of the columns on the west side of the tower are split and offset. In other words they form an A below grade, that is probably because they straddle the below grade ramp that leads to T1's freight dock.

The earthcam hi-res shows this.

By the way, they erected alot of columns on the south-west .

[Big Towers]

Are the tower cranes that are currently installed on the 2WTC going to rise along with the tower, or are they going to install new ones once the 2WTC reaches street level?

[Zensteeldude]

The current cranes are capable of going to the top.