Miami Beach, Champlain Towers South apartment building collapse, Part 10 79

[SFCharlie]

A continuation of our discussion of this failure. Best to read the other threads first to avoid rehashing things already discussed.
Miami Beach, Champlain Towers South apartment building collapse
Miami Beach, Champlain Towers South apartment building collapse, Part 02
Miami Beach, Champlain Towers South apartment building collapse, Part 03
Miami Beach, Champlain Towers South apartment building collapse, Part 04
Miami Beach, Champlain Towers South apartment building collapse, Part 05
Miami Beach, Champlain Towers South apartment building collapse, Part 06
Miami Beach, Champlain Towers South apartment building collapse, Part 07
Miami Beach, Champlain Towers South apartment building collapse, Part 08
Miami Beach, Champlain Towers South apartment building collapse, Part 09


SF Charlie
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[SFCharlie]

Wow! Stunning.

SF Charlie
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[Santos81]

When the bulk of the collapse happened, it seems in photos that the stucco ceiling going across the front of the first floor detached from the slab and fell across the driveway and right over a black SUV parked there. I suspect that this blocked the front doors and it wasn't immediately realized in the dark and confusion.

The Automatic Doors at the main entrance don’t appear to have Emergency Breakaway operation marked at minimum; at worst they don’t have breakaway from the interior.

I also questioned this, as it would be a long walk around to the beach side to get easy access to the pool deck. I imagine she could have climbed down near where the sideways car was, as she got an injury at some point.

The interior route perhaps? This is the path followed according to her own statement.

 

[LionelHutz]

SF Charlie - that’s exactly what I think the top two arrows point to. The building visible behind are parts that haven’t dropped either at all or as much. I think the bottom arrow points to the 12th floor.

Js5180 - Im still not sure what bands you mean. Your arrow isn’t clear at all. Those appear smooth in real life ao it’d be rather difficult to know if they move vertically by looking at them and the stuff On top of them does drop so the most likely conclusion I could make is that they are also dropping.

 

[MaudSTL]

Quote:

The guard was helping people escape from the basement. It's unclear how she got there, being as how there's no access to the stairs from the lobby?

I also questioned this, as it would be a long walk around to the beach side to get easy access to the pool deck. I imagine she could have climbed down near where the sideways car was, as she got an injury at some point.

I too questioned this. In reviewing Ileana Monteagudo’s (611) interviews, it seems that she made it all the way down to the ruined garage and there encountered Shamoka Furman who guided her out.

>>>>>Edited. Ms. Monteagudo mentions climbing and having to get across a gap that was so wide that she would have had to jump if she hadn’t found a place to put her foot so she could instead step over the gap. Per the WaPo feature, they ended up in the visitor parking lot.

 

[Santos81]

Rendering with reference objects aligned with CCTV frame for reference. Something is still not quite right about the positioning of the camera and/or the reference objects.

The camera is located at:

N 25° 52.32451069'
W 80° 7.21234571'
Elev: 15’ NAVD
Direction: 326° Magnetic
Azimuth: 0°

 

[Spartan5]

Js5180

Can you explain what parts of the building the 3 arrows are pointing to?

From top to bottom:
PH parapet wall
12th floor parapet wall
11th floor balcony

All of which appear to have followed the stories below them down the 1.5 floors or so that were in the process of collapsing when the video started.

Note that there are no columns standing proud above that front face of the building as were observed elsewhere during both the collapse of the reminding portions and subsequent demolition of the remainder. As those at the front face of the building were riding it down at that point.

 

[SFCharlie]

The camera is located at:

Thanks for the info!
One of the problems in duplicating the CCTV view is that our object of interest is in a far corner of the frame, where the most distortion from the very wide angle lens in greatest.


SF Charlie
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[Santos81]

One of the problems in duplicating the CCTV view is that our object of interest is in a far corner of the frame, where the most distortion from the very wide angle lens in greatest.

Not an issue with the right software suite. It’s going to be extremely difficult from within AutoCAD Architecture alone.

Autodesk flow of:

Civil3D -> Revit -> 3DSMax

This will be far easier and yield a 100% accurate view.

 

[MarkBoB2]

The first photo below shows the first frame of the surveillance camera video. On the extreme left-hand corner of the Champlain Tower building we can see that both windows and parapets appear to be dark while the undersides (i.e., ceilings) of the balconies appear to be light. This is because: 1) the camera is located close to the ground, which gives it a view of the undersides of the balconies, and 2) the photo has been taken at night when the only illumination of the Tower is from the adjacent building, which means that we are viewing features by reflected light only. Since more reflection is produced by the undersides of the balconies they appear to be light, while the windows and parapets reflect the light away from the camera causing them to appear to be dark. The relative brightness of these same features appears to be noticeably different under daylight illumination as shown in the second photo below.

Since both windows and parapets appear to be dark while the bottoms of balconies appear to be light, there should be the following layers on top of each other over the right middle section of the building (from bottom to top):
1) 12th floor window (dark)
2) 12th floor balcony ceiling (light)
3) 12th floor parapet (dark),
4) PH windows (dark),
5) PH balcony ceiling (light), and
6) PH parapet (dark).
Note that the PH windows in this section of the building are obscured by the 12th floor parapet, which should make them appear to be half the height of the PH windows in the right corner part of the building. But the 12th floor parapet also appears to be dark to the eye, so the PH windows in this section of the building actually appear in the photo to be the same size as the PH windows in the corner of the building.

Over the left middle section, above the partially lighted 12th floor, the following layers should be seen (from bottom to top):
1) 12th floor window (lighted)
2) 12th floor balcony ceiling (light)
2) 12th floor parapet (dark).
Note that the light 12th floor balcony ceiling merges into the lighted 12th floor window, making the lighted 12th floor window in the photo appear to be taller than normal.

If we now look at the first frame of the best imagery we can find of the CCTV surveillance video, and not merely the blurred image shown above, what we actually see over the middle right section is this (from bottom to top):
1) 12th floor window (dark)
2) 12th floor balcony eiling (light)
3) 12th floor parapet (dark),
4) PH windows (dark),
5) PH balcony ceiling (light) - but thinner on the left than on the right
6) No dark layer above the light layer.

This implies to me that the entire PH parapet over the right middle section of the building is missing, along with part of PH balcony on the left-hand side of this right middle section.

The simulation by rodface appears to be quite realistic, and he should be congratulated for his effort. But I would recommend that he change the brightness levels of the balcony ceilings and parapets to better simulate viewing them in reflected light than in daylight. This should then bring his simulation even closer to the CCTV video.

 

[Santos81]

the photo has been taken at night when the only illumination of the Tower is from the adjacent building

What about the pole lighting of the public beach access and plaza level exterior lighting at CTS?

 

[MarkBoB2]

Santos81 asked:

What about the pole lighting of the public beach access and plaza level exterior lighting at CTS?

Good point. I don't know how these light sources might change the relative brightness of the building features. But one can clearly see in the CCTV photo that the illumination is higher on the left-hand side of the building than on the right-hand side, implying that reflected light is being used. The photo taken in daylight is more uniformly illuminated.

 

[Santos81]

Good point. I don't know how these light sources might change the relative brightness of the building features. But one can clearly see in the CCTV photo that the illumination is higher on the left-hand side of the building than on the right-hand side, implying that reflected light is being used. The photo taken in daylight is more uniformly illuminated.

Wouldn’t hurt to start with the PA corridor lighting…

 

[SFCharlie]

Windows only appear dark if the room lights aren't on. We can gauge the reflected light by the large vertical stucco stripes. The appearance of the parapets can be gauged by the remaining parapets on the eastern most section. It is the same for the balcony undersides.
(Please note that the first frame is uniformly dark, and the frames gradually lighten up until at least the fifth frame.) (This is why I use brightness and contrast setting to attempt to obtain uniform appearance through out.)

 

[LionelHutz]

Nice theory, but by the time you find a clearer frame, like the one I captured part of, the camera can no longer see the under side of any of the overhangs in the collapsing part. I’d say it’s more likely those slabs have hinged down so the parapets are being more lit than the other parts of the building.

 

[Nukeman948]

the photo has been taken at night when the only illumination of the Tower is from the adjacent building,

If we still want accurate lighting, we know there was more illumination than just from the adjacent building. There was a full moon out to the South/South-West. That is why the East side looks so dark compared to the South side.

 

[gonefishing2]

[highlight #FCE94F]Accommodation to Reinforced Concrete High-Rise Building Deformations and Movements[/highlight]
Apr, 2014 By Songtao Liao, Ph.D., P.E., M. ASCE, Benjamin Pimentel, P.E., Danny Jadeja, M.S., P.E. and Sunghwa Han, M.S., P.E., S.E., LEED AP In Articles, Structural Design Comments 0
During their service life, high-rise buildings and the associated nonstructural components endure various movements and deformations. Although the deformations and movements are not life threatening, inappropriate design of buildings and associated nonstructural components could induce expensive economic consequences in the long-run and, in order to ensure proper building behavior of the superstructures and the attached nonstructural elements, should not be ignored. In this article the possible deformations and movements of reinforced concrete high-rise buildings and the accommodation of the affected components are discussed.

[highlight #FCE94F]Common Deformations and Movements
Common, inevitable building movements and deformations include: differential column shortening, lateral story drift, building racking, slab and beam deflection, thermal deformation and building dynamic vibration, etc.[/highlight]

PDF Article Attached.

 

[gonefishing2]

[highlight #FCE94F]VIBRATION DESIGN OF CONCRETE FLOORS FOR SERVICEABILITY1[/highlight]
Bijan O Aalami2
This Technical Note covers the design of concrete floor systems for vibration, with an emphasis on simple and expeditious first estimates for a floor’s vibration response. The objective is to determine whether a floor meets the serviceability requirements for vibration using conservative values, or whether a more detailed analysis is warranted. The Technical Note includes several numerical examples to illustrate the application of the procedures presented.
SCOPE
In general, the vibration response of a concrete floors is attributed to:
 Consequence of foot drop in residential and commercial floors;  Rhythmic vibration, such as in dance and sport events
 Vibration in laboratories; manufacturing facilities
 Vibrations due to vehicular traffic outside a facility
 Vibrations due to operation of machinery
 Transient impulse due to earthquake, wind or other impact loads
The focus of this Technical Note is design for vibration in residential and commercial buildings, due to foot drop of walking occupants.

 

[Js5180]

It strikes me as strange, that you should choose a frame where one of the vertical white lines is obviously broken to make your case?

Well, the choice of that frame was unintentional.

But - since you point out the broken band - is it showing any downward movement? Clearly it has some sort of break or damage at a particular spot. Now you have a point of reference - does it descend at all in the time it is visible?

 

[SFCharlie]

- is it showing any downward movement? Clearly it has some sort of break or damage at a particular spot. Now you have a point of reference - does it descend at all in the time it is visible?

Yes (I believe that the frame you choose is #28. If I look at frame 33, without moving the blue arrow, I see that the brake has fallen and is fragmenting.)
Frame # 028 Column break appears at blue arrow.jpg

Frame # 033 shows column falling.jpg

SF Charlie
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[Vance Wiley]

Been there done that. 23 story, CIP posttensioned floors, exterior of spaced bearing walls with integral columns alternating with full height curtain walls. Central elevator and utility core of concrete walls.
Window sections attached to steel framing of two or three story segments, side attached to weld clips embedded in the concrete slabs.
Steel framing for glazing pulling away as much as a foot - maintenance had welded clips to steel verticals and set floor anchors to attach come-a-longs and restrain the movements.
Observed conditions, calculated shortening of the building over about 40 years, and determined there was a lack of expansion clearance in the splice joints and connections of the steel verts, and as the building shortened the steel buckled. Floors prevented buckling inward so they buckled outward.
Advised they cut sufficient clearance at joints in vertical steel framing.
End of file.