Thailand/Myanmar Earthquake: VIDEO Dramatic collapse of a high rise in Bankok 1

[human909]

I have no engineering commentary at this stage. But this does capture a near complete collapse:

https://twitter.com/x/status/1905511502435791007

https://twitter.com/x/status/1905515797234991340

 

[FacEngrPE]

7.7 magnitude earthquake, building under construction. Many under construction buildings will not meet design case load capacity, and this was a strong shaking. Many other buildings / structures damaged. This is clearly a tragedy.

Building collapses in Bangkok after powerful earthquakes rock Thailand and Myanmar​

By Associated Pres
7:00pm Mar 28, 2025

 

[bones206]

It looks like the structural elements were nominally complete since they were already adding glazing. I wonder if the tower crane interaction played a part.

 

[thebard3]

Yeah, I'm not sure that had anything to do with 'under construction', as you can see the sides begin to crumble as a whole before the thing comes down.

 

[IRstuff]

Yikes, we were just there in November

 

[LittleInch]

If you step through it slowly, yes the windows start to all fall out, but the key is the collapse in the middle of at least two of those outer columns which just snap in half and the the whole pancake collapse starts.

Very twin towers like in design by the look of it, central concrete core and then concrete outer columns,

 

[JAE]

I’ve seen where they have upgraded the event to an 8.2. That’s a big one.

 

[FacEngrPE]

Link to USGS shake map https://earthquake.usgs.gov/earthquakes/eventpage/us7000pn9s/shakemap/intensity

Bangkok ground shaking was nowhere near as intense as near the fault.

 

[IRstuff]

The live map on the site puts the magnitude in/around Bangkok at around 4.6, although there are areas pushing 4.9, which should have been a minor event for known seismically active region.

 

[Sym P. le]

Chatuchuk, where the building collapsed is rated at 5.7

 

[human909]

Sorry for not posting more in my original post. I was tired and didn't have much to add.

As reports have come out, particularly from Myanmar, we are heading the true tragic extent of this natural disaster. (Which obviously incorporates many many engineering disasters.). The number of deaths recorded could rapidly increase as local authorities and others get a chance to properly assess the situation. In terms of death and damage this building is likely a just a blip on the radar. But from and engineering perspective this will likely remain of high interest.

Why did this NEW high rise fail when seemingly the majority if not all others of a similar vintage and supposedly built to as similar or less conservative code survive?​

 

[IRstuff]

Chatuchuk, where the building collapsed is rated at 5.7

The USGS map for the area is showing M5.1

I don't think we ever got that far north in the city; we were mostly about 5 miles south of the building that collapsed.

 

[Sym P. le]

The latest reporting is that the collapsed structure was a Chinese development, leading to speculation that it had various design or construction deficiencies. Videos taken from various vantage points offer differing ideas of the collapse initiation though in the end, I believe it will be seen as a foundation failure - Youtube.




From USGS shakemap/intensity

 

[bones206]

Some thoughts/observations:

The lower exterior columns spanned multiple stories and would have been vulnerable to progressively greater p-delta effects.

There were adjacent lower structures that may have kneecapped the tower if they were oscillating out of phase.

It appears the tower core was offset to one side of the building.

 

[human909]

EDIT and summary:
The last video linked shows the pr-collapse incident approximately 5seconds before the collapse.

I am fairly confident the collapse was initiated at the base of the core. We can all but rule out the exterior columns. The rear exterior columns adjacent to the core could have gone first but then I'd expect a less symmetric collapse about the core. Instead we can see the core collapse and the rest of the floor and columns go and the 0.5-1s later then rest of the columns are joining it.

Some thoughts/observations:

The lower exterior columns spanned multiple stories and would have been vulnerable to progressively greater p-delta effects.

There were adjacent lower structures that may have kneecapped the tower if they were oscillating out of phase.

It appears the tower core was offset to one side of the building.

I was going to agree with you enthusiastically. However after watching multiple other videos available online those lower exterior columns were some of the last to go. From what I can see the core was the first thing to collapse. You can see this from the tower crane starting its downward movement very early. And the façade folding up on itself as it is briefly held up by the external columns while internal support is lost.

You can especially see the way the the collapsed seemed to rapidly spread from the core at the central rear in a few vidoes. I've yet to see a vidoe that properly shows the rear of the building. This is a good video, frame by frame is great to get an idea of the progression.

You can also hear the noises from the structure prior to the collapse and see the tower crane swaying quite significantly.

UPDATE:
With a bit of help from google earth I found a rear view of the building. There must be video out there somewhere showing the collapse from this view.

EDIT AGAIN:
In this video here you can distinctly see and hear the initial collapse. You can see the building drop maybe 100-200mm, while remaining "intact" and it remained like that for another 5 seconds before the collapse.

Moment skyscraper under construction collapses in Bangkok after earthquake – video

Footage shows moment tower block under construction collapses in Bangkok after city rocked by earthquake

www.theguardian.com

 

[Sym P. le]

The lower east face glazing doesn't move much initially. The ground level core east face (if that's what it is) doesn't move at all. I say if that's what it is because the roof level core appears much smaller and set back further, unless that top portion is just a reduced cap. In the end, it looks like the west core face drops first and pulls the rest of the building down with it.

 

[bones206]

I think the tower crane was mounted inside the core somehow. That Fox10 video that human909 posted really shows the cab and counterweight swaying with large displacements well above the roofline. The reaction forces to that counterweight motion inside the core would have been massive.

 

[human909]

I think the tower crane was mounted inside the core somehow. That Fox10 video that human909 posted really shows the cab and counterweight swaying with large displacements well above the roofline. The reaction forces to that counterweight motion inside the core would have been massive.

Except the tower crane isn't likely to trigger a collapse from the bottom. If it was a collapse from the top then I'd be looking closely at the crane. The weight and moment of the crane at the base is pretty negligible compared to the weight of the building.

Have a look at the last video that you have to click through to the Guardian to see. There was a clear event 5s prior. It wouldn't surprise me if there were even prior events as the number of mobile phones recording specifically directed at that building does indicate it it was giving indications prior to collapse.

 

[hetgen]

Collapse likely from a weak-story mechanism (slender roof columns) and stiffness discontinuity, causing progressive failure.

Watching the video from The Guardian, it seems the roof was not a factor in the collapse. The collapse definitely began at a lower level.




Heartfelt condolences to the victims.

\

 

[Sym P. le]

Nice sequence. Given the number of videos posted, the hardest part of the evaluation is finding the one that shows the initiation, and we still have more work to do there. It was intriguing to think the penthouse led the collapse but obviously it wasn't the case.