Market Square Tower: Multifamily High-Rise At 777 Preston St.

[toxtethogrady]

It is. I am surprised to see that style, which seems to be more suited for Chinese supertalls like the Chow Tai Fook and the Ping An.

[arche_757]

Is it?  Most building cores are large.  Remember this is a 40 floor apartment tower.  They've got to provide emergency egress for the hundreds of people who will live here.  Not to mention the US does not allow emergency egress via elevators (despite them being housed in 2-hour rated firewalls), so stairs are the ONLY way to evacuate in an emergency that is allowed by code.

[monarch]

^^^ THIS!  i am not abreast at all to construction techniques.  however, even i find that this foundation construction is a bit unique / bizarre for an edifice of this size and scale.

[jmitch94]

This is really going to be a massive building 

[Purdueenginerd]

What is that large inner core of the building? I'm sure its partly for elevators but it seems really large.

 

Those cores/elevator shafts encompass a large portion of the shear and lateral resistance of the structure, making the structure stiffer and less likely to laterally move significantly during seismic or wind events. They can also allow for larger 'floor plates' uninterrupted by support column which can be beneficial for apartment or office units. One of the more famous examples of a skyscraper with a large core is the World Trade Center towers before 9/11. 

Edit:

 

Some light reading http://www.purdue.edu/newsroom/research/2011/110920BowmanSkyscrapers.html

 

I used to work at this lab when I was an undergrad on the project listed above, very early in the research project (2007-2008). 

 

 

 

Edited March 30, 2015 by Purdueenginerd

[Tumbleweed_Tx]

WTC before 911 didn't have a core, it had elevator shafts and stairways. . That's why it collapsed as all the downward force was supported by the outer columns, which were compromised.

[democide]

WTC before 911 didn't have a core, it had elevator shafts and stairways. . That's why it collapsed as all the downward force was supported by the outer columns, which were compromised.

 

Nope, you're wrong.  The twin towers had a strong inner core made up of 47 columns.  It shared the gravity load with the outer columns.   If anything, the top part (above the crash location) should have tipped over.  That actually did happened to the south tower.  However, as the top part tipped over, the lower part collapsed completely onto itself without that downward force you speak of. 

[Purdueenginerd]

WTC before 911 didn't have a core, it had elevator shafts and stairways. . That's why it collapsed as all the downward force was supported by the outer columns, which were compromised.

 

Not to start an argument, regarding WTC, thus I apologize to everyone else. But you are very incorrect. Please see attached images of WTC during construction for what is clearly the structural core. 

 

 

 

 

I would suggest reading the NIST reports in regard to the structural analysis and failure mechanisms of the WTC towers. They talk about the original calcs, original drawings, the load analysis, and likely and confirmed damaged support columns. 

 

http://www.nist.gov/el/disasterstudies/wtc/wtc_finalreports.cfm

 

Edit: Fair warning, some of the PDFS on the link are over 60 mb. Its been a few years since I read through them all, but if youre into structural analysis and failure analysis its a good read. 

Edited March 31, 2015 by Purdueenginerd

[jmitch94]

God the amount of steel in those towers was insane, not to mention the money it must have cost to build those behemoths.  

[Luminare]

Not to start an argument, regarding WTC, thus I apologize to everyone else. But you are very incorrect. Please see attached images of WTC during construction for what is clearly the structural core. 

 

 

 

 

I would suggest reading the NIST reports in regard to the structural analysis and failure mechanisms of the WTC towers. They talk about the original calcs, original drawings, the load analysis, and likely and confirmed damaged support columns. 

 

http://www.nist.gov/el/disasterstudies/wtc/wtc_finalreports.cfm

 

Edit: Fair warning, some of the PDFS on the link are over 60 mb. Its been a few years since I read through them all, but if youre into structural analysis and failure analysis its a good read. 

 

This building only failed in fire proofing, and in structure used for the flooring. They used web joists everywhere in this thing! and on top of that they used spray on fire proofing. So not only do you have a floor system that is super light, but you have spray on fire proofing with given the right amount of impact or even the right amount of temperatures could render it useless. However you can't really blame the engineers or even the architect for this design. It's only foolish in retrospect, but you can't really design a building to take the full force of a airplane collision! That's just absurd. The design was truly revolutionary for the time because it created an interesting relationship between the skin of the building and it's core and both had to work together. The exterior, most people forget, was a load bearing facade. The entire skin was an exoskeleton. This exoskeleton and the core were the parts of the building that took the load of the building freeing the entire floorspace of the interior making the building very flexible for tenants.

 

Now why are we talking about WTC?

 

Edit: From learning about this building and my structures prof in college. Never use open steel web joists for your structural floor! Only use it in roofing. I think it's good advice to live by

Edited April 1, 2015 by Luminare

[BigFootsSocks]

Yeah but can jet fuel melt steel beams?

[Purdueenginerd]

Hope youre joking but I do get this question a lot. 

 

The answer is no, But it doesnt have to.  It also changes the coefficient of thermal expansion for steel as a function of temperature. I wont get into the material science of steel transitioning from solid to liquid, and how thats not an instantaneous occurance . But if you truly want to read about how temperature affects steel members.

 

Go to AISC (American Institute of Steel Construction): Steel Construction Manual and refer to the equation on 2-31. This equation will give you the coefficient of thermal expansion for steel from 100 to 1200 degrees F. From that, you can calculate, how much a member will 'grow' under a given temperature, which puts new stresses on the connections.

PDF would be too large to provide here, and its about a 500 dollar design code. 

 

Then, go to AISC Design Guide 19: Fire Resistance of Structural Steel Framing

Link (Pdf): http://portales.puj.edu.co/wjfajardo/ESTRUCTURAS%20MET%C3%81LICAS/AISC/AISC%20Design%20Guide%2019%20-%20Fire%20Resistance%20Of%20Structural%20Steel%20Framing.pdf

Go to Table X.1 on Page 70 of the PDF and you'll see that steel starts to lose yield capacity at around 800 degrees. 

 

 

 

[BigFootsSocks]

[Luminare]

 

To put what he said into perspective. Wood actually performs better in a fire than bare steel! It's like heating any metal, once it begins to heat up you bringing it closer to the state at which it was formed in the first place meaning it becomes more malleable. So going back to the WTC example (which I hope this is the end of this example so it doesn't get further away in this thread) the beams didn't melt, instead the started to slowly bend from the increased load which it would normally be able to hold in it's normal state, but because of the heat it lost that property and started to bend meaning it couldn't hold the load and simply collapsed. All that needed to happen btw was that one to two floors completely failing and the rest was a domino effect as each floor staked like pancakes all the way down to ground zero.

[democide]

Hope youre joking but I do get this question a lot. 

 

The answer is no....

 

Thank you for your response, very informative.  NIST also agrees that jet fuel does not melt steel, and they adamantly deny that melted steel was found at ground zero, yet we have eyewitnesses who said they saw it, and there is video and photo evidence of it too.

[Timoric]

-

 

Edited July 8, 2019 by Timoric

[nonenadazilch]

Thank you for your response, very informative.  NIST also agrees that jet fuel does not melt steel, and they adamantly deny that melted steel was found at ground zero, yet we have eyewitnesses who said they saw it, and there is video and photo evidence of it too.

 

Without rational explanation is WTC 7's improbable free-fall into its footprint.

 

All that needed to happen btw was that one to two floors completely failing and the rest was a domino effect as each floor staked like pancakes all the way down to ground zero.

 

Also improbable.  The steel structure below the impact zones were unaffected by any heat and therefore - minus any other destructive force upon it - present an imposing upward resistance to the falling of the failed structure above it.  Yet as history shows they offered no resistance whatsoever to the downward force of the upper floors.  At a minimum, the rational outcome for each tower would be a non-symmetric collapse whereby, instead of falling relatively 'neatly' into its footprint, chunks of the building would be strewn over a much wider swath at ground-level with a lower segment of the tower still standing.  For this scenario to play out in the second tower in virtually mirror fashion is quite a feat indeed.  The weakness and general acceptance of NIST's presentation survives due to our collective servility in the midst of national grief, uber-patriotism and its accompanying jingoism.

Edited April 3, 2015 by nonenadazilch

[wxman]

Without rational explanation is WTC 7's improbable free-fall into its footprint.

 

 

Also improbable.  The steel structure below the impact zones were unaffected by any heat and therefore - minus any other destructive force upon it - present an imposing upward resistance to the falling of the failed structure above it.  Yet as history shows they offered no resistance whatsoever to the downward force of the upper floors.  At a minimum, the rational outcome for each tower would be a non-symmetric collapse whereby, instead of falling relatively 'neatly' into its footprint, chunks of the building would be strewn over a much wider swath at ground-level with a lower segment of the tower still standing.  For this scenario to play out in the second tower in virtually mirror fashion is quite a feat indeed.  The weakness and general acceptance of NIST's presentation survives due to our collective servility in the midst of national grief, uber-patriotism and its accompanying jingoism.

 

It's not improbable you nincompoop. The buildings pancaked didn't they? And not necessarily neatly either I might add. Did you not see planes fly into the buildings at over 400 mph? Survivors inside those builds commented on how violantly those buildings swayed--some saying they thought the building was going to topple upon impact. I'm not a structural engineer but I assume that structure was compromised beyond repair at the point of impact, even if the towers had remained standing due to bent beams and twisting of the towers.

 

Did you not see the collapse of the buildings? They did exactly what you said was improbable. If those planes, which  by the way were wide body 767's, no small jet, had hit only the top 2 or 3 floors, I would agree that it would be more improbable to cause a complete collapse of said structure. But those planes compromised the structural integrity (fire proofing) around floor 76 (nor sure of the exact floors). Using floor 76 as the example, there was still a 34 story building above impact. That's 34 stories of steel, glass, furnture ect. Once those support columns, the ones that remained in tact, gave way, there was no way to stop the cascade with that kind of weight above it.

 

Look at the link:

 

https://www.youtube.com/watch?v=k_64RigP1Fk

 

The clips at 40 seconds, 1:10, 1:35, 3:06 among others make it clear that this was not a "neat, unform" pancake collapse. The top of the building was nearly decaptitated. Look how the top of the building appears to fall off the rest of the tower, leans over if you will, before subsequently collapsing. So I'm not really sure what your point is.

 

Using the word ''improbable'' makes you seem like a conspiracy theory wack job who is certain the building were brought down by dynomite verses packed jetliners. Let me guess, you also think Elvis is alive because you saw him in Vegas?

Edited April 3, 2015 by wxman

[Luminare]

It's not improbable you nincompoop. The buildings pancaked didn't they? And not necessarily neatly either I might add. Did you not see planes fly into the buildings at over 400 mph? Survivors inside those builds commented on how violantly those buildings swayed--some saying they thought the building was going to topple upon impact. I'm not a structural engineer but I assume that structure was compromised beyond repair at the point of impact, even if the towers had remained standing due to bent beams and twisting of the towers.

 

Did you not see the collapse of the buildings? They did exactly what you said was improbable. If those planes, which  by the way were wide body 767's, no small jet, had hit only the top 2 or 3 floors, I would agree that it would be more improbable to cause a complete collapse of said structure. But those planes compromised the structural integrity (fire proofing) around floor 76 (nor sure of the exact floors). Using floor 76 as the example, there was still a 34 story building above impact. That's 34 stories of steel, glass, furnture ect. Once those support columns, the ones that remained in tact, gave way, there was no way to stop the cascade with that kind of weight above it.

 

Look at the link:

 

https://www.youtube.com/watch?v=k_64RigP1Fk

 

The clips at 40 seconds, 1:10, 1:35, 3:06 among others make it clear that this was not a "neat, unform" pancake collapse. The top of the building was nearly decaptitated. Look how the top of the building appears to fall off the rest of the tower, leans over if you will, before subsequently collapsing. So I'm not really sure what your point is.

 

Using the word ''improbable'' makes you seem like a conspiracy theory wack job who is certain the building were brought down by dynomite verses packed jetliners. Let me guess, you also think Elvis is alive because you saw him in Vegas?

 

Dude don't even give him the time of day. He clearly has an agenda. Lets not fuel it I researched this while in college during my structures course. The guy simply can not accept the realities of what happened. The reason why he is using "improbable" is because he clearly is a conspiracy theorist. The floors did pancake on top of each other. The debris which radiated out from the building was from the floors above where the planes struck, anything that was inside of the office, and exoskeleton falling outwards since it no longer had it's connection with the core structure. In fact I would like a mod to please move or delete any posts about WTC or conspiracy as we are now far away from the originial intent of the question asked about the core of this building and how it relates to WTC....which it does only in look, but is constructed from concrete and not out of steel making this an entirely different case from WTC making everything that has been discussed about WTC completely irrelevant.

[Purdueenginerd]

Deep Breath.

 

/Sigh

 

 

Nonenadalize clearly never took a Highschool physics.

 

W=∫Fdx

W = ΔE

KE=1/2 mv^2

ΔKE=∫Fdx

Where F=Impact force, W equals Work, E equals Energy in a system, KE is Kinetic Energy. Your homework, tonight is to estimate the mass of 10 floors. Moving, 12 feet due to gravity, and determine how much force is applied.  When you do that: Find me a construction material on this planet that can resist that kind of energy and force. 

 

 

 

Edited April 3, 2015 by Purdueenginerd

[Purdueenginerd]

 In fact I would like a mod to please move or delete any posts about WTC or conspiracy as we are now far away from the originial intent of the question asked about the core of this building and how it relates to WTC....which it does only in look, but is constructed from concrete and not out of steel making this an entirely different case from WTC making everything that has been discussed about WTC completely irrelevant.

 

agreed, and I apologize for kind of introducing it as an example. 

[Subdude]

Guys, this has wandered too far off topic.  Please address future posts in this topic to the topic.

 

 

[hindesky]

 

[jmitch94]

wow this is speeding up rather quickly 

[HtownWxBoy]

Seriously ... this tower is rising fast! 

[H-TownChris2]

It's already the height of the garage that's right next to it! Wow

[BigFootsSocks]

I'm still waiting to see what's on that side of this tower...

[DRUTH]

updated photo:

[Gator Purify]

updated photo:

 

At this rate, Market Square Tower will start to peek over the garage by late June.

[toxtethogrady]

Or sooner.