PHILADELPHIA | FMC Tower @ Cira Centre South | 736 FT | 49 FLOORS - Page 122

phillyheights · #**2421** Posted **Aug 12, 2015, 7:30 PM**

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this is better!

mmikeyphilly · #**2422** Posted **Aug 12, 2015, 9:19 PM**

Quote:

Originally Posted by japmes

I still don't understand what's happening with the core. How will the elevator shafts continue upward?

I'm glad I'm not the only one who is in suspense!

Maybe they won't have elevators. Since these levels will most likely be occupied by College Age folks (I was gonna say kids, but I'm old enough already!), Well, maybe they will just have 21 floors or so with steps?!?

But from what it looks like, they may continue with a separate core altogether? Maybe? I picture an atrium where they catch the separate elevator. They take an express to the 28th, 29th? We shall see. If anyone wants to tell us, I'm all ears.

Plokoon11 · #**2423** Posted **Aug 12, 2015, 9:55 PM**

Theres going to be a core it will be half the size stepped down for the next portion.

miesian · #**2424** Posted **Aug 12, 2015, 9:55 PM**

Quote:

Originally Posted by mmikeyphilly

I'm glad I'm not the only one who is in suspense!

Maybe they won't have elevators. Since these levels will most likely be occupied by College Age folks (I was gonna say kids, but I'm old enough already!), Well, maybe they will just have 21 floors or so with steps?!?

But from what it looks like, they may continue with a separate core altogether? Maybe? I picture an atrium where they catch the separate elevator. They take an express to the 28th, 29th? We shall see. If anyone wants to tell us, I'm all ears.

. They are transitioning from steel to concrete for the upper floors. When they assemble the concrete climbing structure, which will be a smaller core from the office part, it will move fast. A composite.

jsbrook · #**2425** Posted **Aug 12, 2015, 10:38 PM**

Quote:

Originally Posted by Plokoon11

Theres going to be a core it will be half the size stepped down for the next portion.

Will you be able to ride from ground to top floor without elevator transfer? There are worse things in the world but elevator transfer would be annoying for AKA guests and the like.

gttx · #**2426** Posted **Aug 12, 2015, 11:13 PM**

Quote:

Originally Posted by jsbrook

Will you be able to ride from ground to top floor without elevator transfer? There are worse things in the world but elevator transfer would be annoying for AKA guests and the like.

It sounds like some of the elevators are just dropping out of the core at this point. Ie, one bank will serve the lower levels only, while the other will go all the way up the tower.

RWSMADCONC · #**2427** Posted **Aug 13, 2015, 12:32 PM**

Quote:

Originally Posted by gttx

It sounds like some of the elevators are just dropping out of the core at this point. Ie, one bank will serve the lower levels only, while the other will go all the way up the tower.

As noted above, there is a transition at Level 28. The core that encloses the elevators from Lower Walnut to L28 is about 38 ft x 110 ft; above the 28th it is about 30 ft x 30 ft. The elevators for the residential level are in that smaller portion, and do not stop at the lower floors which are office floors.

The steel frame changes to concrete above L28; big-— steel trusses will be erected over the next 6 weeks to transfer the residential tower to the steel office portion. The residential tower steps back at the north to close to the present core wall (below)---look for the northwest crane to be bismantled after the trusses are erected, and a new core form setup appear to run the core on up ahead of the residential floors.

Any questions?

mmikeyphilly · #**2428** Posted **Aug 13, 2015, 12:52 PM**

Quote:

Originally Posted by RWSMADCONC

Any questions?

Got it! Many, many many thanks

Well, actually there is one question?
Why did the architect/developer decide to go from steel to concrete in the first place? Is it cheaper materials? more desirable settings as opposed to "cold" steel girders, etc. Would it have been cheaper or easier to stay all steel, or was there a specific reason? Okay, I lied that's more than one question!
But Thanks again,

Citylover94 · #**2429** Posted **Aug 13, 2015, 1:29 PM**

If the upper portion of the tower is residential that may be why because concrete insulates sound pretty well.

1487 · #**2430** Posted **Aug 13, 2015, 5:40 PM**

Quote:

Originally Posted by mmikeyphilly

Got it! Many, many many thanks

Well, actually there is one question?
Why did the architect/developer decide to go from steel to concrete in the first place? Is it cheaper materials? more desirable settings as opposed to "cold" steel girders, etc. Would it have been cheaper or easier to stay all steel, or was there a specific reason? Okay, I lied that's more than one question!
But Thanks again,

Most residential buildings are concrete instead of steel. I think one factor is that residential buildings tend to have smaller floorplates and are more conducive to concrete. When you have large floorplates where the perimter of the building can be relatively far from the core I think steel is superior. Another benefit of concrete construction is that you arent really dealing with lead times or the logistical issues of trucking in and lifting beams day after day. the operation is almost totally local (except for concrete truck deliveries) which is a plus. You dont need to add spray on fireproofing with concrete either. I think concrete is often the choice if the building's design parameters allow it-which is not the case with most office buidlings.

http://business.inquirer.net/102225/concrete-or-steel

mmikeyphilly · #**2431** Posted **Aug 13, 2015, 6:32 PM**

Quote:

Originally Posted by 1487

Most residential buildings are concrete instead of steel. I think one factor is that residential buildings tend to have smaller floorplates and are more conducive to concrete. When you have large floorplates where the perimter of the building can be relatively far from the core I think steel is superior. Another benefit of concrete construction is that you arent really dealing with lead times or the logistical issues of trucking in and lifting beams day after day. the operation is almost totally local (except for concrete truck deliveries) which is a plus. You dont need to add spray on fireproofing with concrete either. I think concrete is often the choice if the building's design parameters allow it-which is not the case with most office buidlings.

http://business.inquirer.net/102225/concrete-or-steel

Thanks 1487, That was a great article! Very informative, and it solved a lot of the questions as to why concrete or steel. Thanks for sharing that!

hammersklavier · #**2432** Posted **Aug 14, 2015, 7:42 AM**

Generally (but not always) steel is favored for office construction, while concrete is favored for residential construction. Concrete is more spatially efficient (lower ceiling heights = more stories per vertical feet). Coach Tower being a concrete building is surprising, for example, because one would normally expect a large office building to be steel.

What I am finding surprising is that they're using a mixed construction here. One would think that the benefits of using one mode or another would be cancelled out by the relatively more complex structural engineering required to make a structural transition from steel to concrete.

It'll be interesting to see whether or not a certain large building with a Four Seasons at the top will also have that kind of structural transition...

1487 · #**2433** Posted **Aug 14, 2015, 12:38 PM**

Quote:

Originally Posted by hammersklavier

Generally (but not always) steel is favored for office construction, while concrete is favored for residential construction. Concrete is more spatially efficient (lower ceiling heights = more stories per vertical feet). Coach Tower being a concrete building is surprising, for example, because one would normally expect a large office building to be steel.

What I am finding surprising is that they're using a mixed construction here. One would think that the benefits of using one mode or another would be cancelled out by the relatively more complex structural engineering required to make a structural transition from steel to concrete.

It'll be interesting to see whether or not a certain large building with a Four Seasons at the top will also have that kind of structural transition...

The other thing you have to remember is that many office buildings- especially modern ones like the CC have very high ceilings to allow light to penetrate deep into the floorplan. That is another factor that makes steel more attractive. Residential buildings have lower floor heights and I believe concrete works better when you have less floor height. Also, you don't need huge column free expanses in residential buildings because each floor is divided up into so many units anyway. I found contradictory info about which method is faster- some articles say an efficient concrete pouring operation is faster than steel while other sites said steel is faster to erect and less labor intensive. I also read that advances in concrete have made it more competitive vs steel in many hi rise applications. It's stronger than it used to be and there are types that cure faster than older types which means you can pour more floors more quickly.