What is going on in this photo?

HX_Guy · #1 Posted **May 1, 2009, 5:51 AM**

I figured if anyone can answer this, it's people who read this sub-forum.

This is a project currently going up in Phoenix (obviously). One tower is already 19/27 floors up and the other is still a "maybe" in a lot of people's eyes yet the developer says it will happen.

The second tower is supposed to go up where the large square rebar (or whatever) is in the following pic once the parking garage reached street level.

What is the large square section and is it something related to the parking garage or is it related to the second tower? Basically...does it mean the second tower is a reality or...

Coldrsx · #2 Posted **May 1, 2009, 10:21 PM**

looks like the raft slab to me... but yes, pouring that would likely mean the 2nd tower is going ahead (mind you it could still be capped at grade)

HX_Guy · #3 Posted **May 2, 2009, 12:13 AM**

And a "raft slab" is?

mersar · #4 Posted **May 2, 2009, 2:46 AM**

In towers that use it, its a huge slab that is usually several feet to several meters thick that acts as the foundation for the tower itself. For instance the Bow in Calgary has one that is roughly 10 feet thick that the tower sits on, whereas the parking garage around it would only have a slab thick enough to act as the floor on the ground

harryc · #5 Posted **May 2, 2009, 3:01 AM**

This at a later stage (from Chicago, the rebar from the tops of the caissons can be seen as the slightly bent rods sticking straight up.

Full set

Kelvin · #6 Posted **May 2, 2009, 12:54 PM**

It is a bit small for a raft - as the intent of a raft is to float the entire building. It is for sure intended to be a thickened slab, meaning that the immediate area of the thickening is expected to have higher loading.

If you say another building has been planned for that area then it is a strong indication that it could be, for example, an area intended to carry the central shaft and shearwalls. However, it may not necessarily indicate that the second building will be built with the first. Occasionally a second foundation is built "now" in order to not disturb the first building's foundation later on - esp. if deep excavations are required.

HX_Guy · #7 Posted **May 2, 2009, 2:25 PM**

Quote:

Originally Posted by Kelvin

It is a bit small for a raft - as the intent of a raft is to float the entire building. It is for sure intended to be a thickened slab, meaning that the immediate area of the thickening is expected to have higher loading.

The second building's tower portion has a pretty small footprint, especially compared to the first. Here are a coupon renderings...

(Second tower on the left, first tower on the right grayed out)

(Low quality, but again, second tower on the left with first tower currently under construction on the right)

HX_Guy · #8 Posted **May 2, 2009, 9:15 PM**

Sure enough, today it looks like in the picture posted above. One of the workers on side said it's the elevator shaft for the parking garage and tower.

The tower crane going up is supposedly for the parking garage and a third tower crane will go in for the tower on the opposite corner of the lot. That doesn't make a whole lot of sense to me though as shouldn't the tower crane be pretty close to the tower itself so it can be anchored?

GWHH · #9 Posted **Jun 17, 2009, 4:29 AM**

This is an easy one. They are building a secert underground command center for the new world order

Supt11CJ · #10 Posted **Jun 24, 2009, 5:37 PM**

It is a mat foundation for the elevator core of the building. Typical construction for a "mat slab".

Jasonhouse · #11 Posted **Jun 25, 2009, 4:05 AM**

I bet that slab has north of 300 cubic yards of concrete in it...