^That is post tensioned cabling. After the concrete is poured, they will put the cables in tension to strengthen the deck. This allows for much less traditional rebar in the deck.
I was wondering the same thing. It looks like rebar, but I dont understand what its structural purpose would be.
__________________
Chicago Blackhawks, Stanley Cup Champs 2010, 2013, 2015.
Chicago White Sox, World Series Champs 2005.
Chicago Bulls, World Champs 1991, 1992, 1993, 1996, 1997, 1998.
Chicago Bears, Super Bowl Champs 1985.
Bvic, that last picture is great. Thats going to be be one long slab when it levels out after garage level. I'd say 90% of Chicago doesn't know or realize how huge this project is or what the visual impact it's going to make.
I was wondering the same thing. It looks like rebar, but I dont understand what its structural purpose would be.
Concrete works great in compression, but is pretty bad in tension. Basically you can place a lot of weight on a concrete column, but if you were to hang a concrete column from the ceiling you wouldn't be able to hang nearly as much weight from it.
The steel rebar both holds the concrete slab in compression and adds tensile strength to the slab.
__________________
If all others accepted the lie which the Party imposed, if all records told the same tale, then the lie passed into history and became truth. -Orwell
Concrete works great in compression, but is pretty bad in tension. Basically you can place a lot of weight on a concrete column, but if you were to hang a concrete column from the ceiling you wouldn't be able to hang nearly as much weight from it.
The steel rebar both holds the concrete slab in compression and adds tensile strength to the slab.
Rebar takes the tension - concrete takes the compression.
Post tension puts the concrete under compression making it stronger.
in this photo you can see both the rebar (vertical, and horizontal at right angles) and the post tension cables (running diagonally).
__________________
Harry C - Urbanize Chicago- My Flickr stream HRC_OakPark
The man who trades freedom for security does not deserve nor will he ever receive either. B Franklin.
__________________
If all others accepted the lie which the Party imposed, if all records told the same tale, then the lie passed into history and became truth. -Orwell
Thanks for all the great photo updates everybody. The documentation of this project is every bit as impressive as the construction progress so far. I'll be in town next weekend and I'll be sure to snap a few to add to the pool.
The cables take quite a circuitous route, no? The curves don't 'feel' right to me, but they definitely look deliberate and in their final resting place. Interested to see if anyone has more insight.
[QUOTE=harryc;7772128]Rebar takes the tension - concrete takes the compression.
Post tension puts the concrete under compression making it stronger.
[QUOTE=vexxed82;7772269]The cables take quite a circuitous route, no? The curves don't 'feel' right to me, but they definitely look deliberate and in their final resting place. Interested to see if anyone has more insight.
Quote:
Originally Posted by harryc
Rebar takes the tension - concrete takes the compression.
Post tension puts the concrete under compression making it stronger.
The tendons run over the tops of columns. They're sit high in the slab through the column, and low in the slab toward the center of the span between columns. This way, when the cable is pulled, the slab between columns is almost "pulled up".
__________________ Paper is fine, nerf Rock. Signed - Scissors.
The cables take quite a circuitous route, no? The curves don't 'feel' right to me, but they definitely look deliberate and in their final resting place. Interested to see if anyone has more insight.
The tendons run over the tops of columns. They're sit high in the slab through the column, and low in the slab toward the center of the span between columns. This way, when the cable is pulled, the slab between columns is almost "pulled up".
the amount of UP is very small for a HUGE amount of tension, conversely the amount of down will impose lateral tension - so the harder you push down, the stronger you make the slab.
(and yes the curved post tension cables just seems wrong).
__________________
Harry C - Urbanize Chicago- My Flickr stream HRC_OakPark
The man who trades freedom for security does not deserve nor will he ever receive either. B Franklin.
Prev
Linear Mode
