PHILADELPHIA | Comcast Technology Center | 1,121 FT | 60 FLOORS

[1487]

anyone else recall an office buidling needing 3 cranes in this city? The fact that they need 3 to cover the area shows how massive this building is- and the fact that it takes up an entire block definitel factors into it only having 59 floors. If this buidling was on a smaller site it would've been considerably taller. the boom of the crane is now visible (barely) over the top of 2 logan square now. I still can't see any of the building from the north though. Its going to be a while before the core is visible due to 1717 Arch.

[Philly Fan]

Speaking of the third tower crane, look at how long the boom is on that thing--no problem reaching the easternmost portion of the site:

[JawKneeQuest]

Today's 12th Floor (Comcast Center) Update for ya.....

[iheartphilly]

Originally Posted by JawKneeQuest

Today's 12th Floor (Comcast Center) Update for ya.....

Impressive shot. These guys have some big nuts to be working off the low ground-walking on steel beams and cranes. The 3 cranes hopefully will help move this along at a faster pace.

[Plokoon11]

Massive!

[ekt8750]

From the looks of things on the webcam, they're lifting the mobile cranes out of the bathtub right now.

EDIT: Or not lol

[PhillyPhlyr]

Originally Posted by Plokoon11

Id assume no, have you seen how big that core is?

Oh yeah, I get an up close and personal look at it a couple times a week!

Originally Posted by Human Scale

I have not studied structural engineering but I imagine since the core is the core it can stand on its own, being the strongest part. If anything, the steel would be an impediment to the core, although it is not.

Although it is hollow, I understand where you're coming from, I would think they support each other and the core could only rise so high before it needed support to stay standing. (obviously I'm a total amateur with no knowledge of structural engineering whatsoever )

[mmikeyphilly]

Wow! This core is getting (humungous!)

This is such a complicated skyscraper to erect, with all of the logistics and pieces of a huge puzzle to put together. Not the typical cross beam construction. The floor plans (from the animated video) show that the floor plans are open, and some have atriums, etc. Will be very interesting to see how they erect the eastern end.
One question? Has anyone else wondered what those steel beams holding up the southern wall, (on the eastern side). I know this sounds weird, but when I see those beams, I think of how they put beams on the bathtub wall of the destroyed World Trade Center. (To hold back the Hudson!) Is this normal, or are they waiting for steel to be erected there as a permanent structure?

[boxbot]

Originally Posted by mmikeyphilly

One question? Has anyone else wondered what those steel beams holding up the southern wall, (on the eastern side). I know this sounds weird, but when I see those beams, I think of how they put beams on the bathtub wall of the destroyed World Trade Center. (To hold back the Hudson!) Is this normal, or are they waiting for steel to be erected there as a permanent structure?

The pit is so deep and so long that they're needed for reinforcement until the steel gets erected. They're temporary.

[mmikeyphilly]

Yes, that's true. It would make sense that the hole being dug that deep, and with the immense length of the dig, that the supports would make sense. But, going back to December 13, and the Photo taken by volguus zildrohar shows the supports at that location, and not on the northern wall. It seems that they were put in place that far back, and haven't been removed, even 'til now. It just seemed to me that maybe they found some weak foundation problem, or just as a safety against the street caving in. I'm sure they know what they're doing, but it just made me wonder.


[QUOTE=volguus zildrohar;6843020]December 13

[ekt8750]

[QUOTE=mmikeyphilly;7110002]Yes, that's true. It would make sense that the hole being dug that deep, and with the immense length of the dig, that the supports would make sense. But, going back to December 13, and the Photo taken by volguus zildrohar shows the supports at that location, and not on the northern wall. It seems that they were put in place that far back, and haven't been removed, even 'til now. It just seemed to me that maybe they found some weak foundation problem, or just as a safety against the street caving in. I'm sure they know what they're doing, but it just made me wonder.

Originally Posted by volguus zildrohar

December 13

That could be where the concourse opening is and it's just a temporary wall that needs to be propped up.

[TechTalkGuy]

Maybe they found the hidden treasure from William Penn and wanted to safeguard the hidden vault?

If the concourse is on the other side, then that theory makes the most sense.

Still, my imagination would always wonder if there are any hidden treasures beneath the streets.

[1487]

When you have to hold up a wall like that they often inject steel cables into the soil/rock behind that wall and tie them to steel beams to reinforce the structure and resiste the pressured of all that soil on that shoring wall. I'm thinking in that corner underground utilities prevented them from using that method to achieve the necessary reinforcement of that retaining wall so they had to support that wall from the inside of the pit until the permanant stuctural steel is erected to lock everything in place and provide adequate resistance to the bearing pressure of the earth on the other side of that wall.

[ekt8750]

Originally Posted by TechTalkGuy

If the concourse is on the other side, then that theory makes the most sense.

That's SE corner of the foundation and the concourse runs underneath JFK and Cuthbert St so you'd have to think the entrance to that would be on the SE corner.

[Plokoon11]

Green crane goes bye bye.

[ekt8750]

Originally Posted by Plokoon11

Green crane goes bye bye.

Yup and they've started planting some box beams into the foundation on that side near the core.

[summersm343]

Update from Building Philly



https://www.facebook.com/BuildingPhilly

[TechTalkGuy]

Is the core actually rising?
That photo looks no different from the other day.

[hammersklavier]

Originally Posted by Human Scale

I have not studied structural engineering but I imagine since the core is the core it can stand on its own, being the strongest part. If anything, the steel would be an impediment to the core, although it is not.

The most important property of concrete is that it is a "compressive" material. That is, concrete performs well when other stuff (like more concrete!) is stacked on top of it but fails easily when placed under what is called tensile stress, stress that occurs when it is pulled apart instead.

Steel, by contrast, performs extremely well under tensile loads. That's why bridges' structural members -- trusses, girders, cables and the like -- are often made of steel. It performs reasonably well under compression, but where it truly shines is under tension.

Reinforced concrete is concrete poured around a steel mesh. The trick with reinforced concrete is that the concrete's compressive properties and steel's tensile properties have to counterbalance each other; go too far one way or the other and the whole structure will fail. Reinforced concrete performs well under tension as well, which is why incredible structures like the Tunkhannock Viaduct could be built out of it a century ago, and bridges like the Oresund today.

The major structural mechanism for modern steel skyscrapers grows out of the "tube" design, such as was used for the original WTC and Sears Willis Tower. In this design, the floorplates effectively act not unlike bridge decks, their loads being transferred into the reinforced-concrete core and along the building's outer facade. In early tube designs (particularly during the Brutalist era) the outer facade was also concrete and could be used as structural element as well; these days, the steel skeleton itself seems to be more than enough.

[MikeNigh]