Mexico church roof collapses

[JAE]

Here's a news link.

https://apnews.com/article/mexico-tamaulipas-church-roof-collapse-fa4f4a42499533ee8d3517f349ae5d14

 

[JAE]

Video of the collapse here:

https://news.sky.com/video/mexico-c...g-sunday-mass-killing-several-people-12974802

 

[JAE]

It appears some of the pews created some support - possibly saving lives.

 

[JLNJ]

Wow. No snow, no rain, no wind. I wonder how long it stood there prior to collapse.

 

[azcats]

Are these some sort of tension bar?

Roof/Ceiling looks CIP. I don't really understand the system.

[URL unfurl="true"]https://www.elsoldetampico.com.mx/local/iglesia-que-se-derrumbo-en-tamaulipas-tenia-60-anos-de-antiguedad-parroquia-de-la-santa-cruz-10784268.html[/url]

 

[SWComposites]

Held up by prayers?

 

[Sym P. le]

Iglesia Santa Cruz (Parroquia Santa Cruz) - Google Maps Link

 

[Sym P. le]

Western most section remains intact as if the demising wall offered support.

elfinanciero.com.mx

 

[Sym P. le]

Were structural issues already apparent when this photo was taken?

 

[Lomarandil]

SymPle, that just looks like form marks to me.

Thin shell folded plate roof. Yes, tension ties transverse to resist the thrust at the eaves.

The video angle I'm seeing makes me suspicious of the collapse originating at the far (obscured) wall. Seems like the plate is moving laterally away a good bit at the near peaks prior to full collapse.

 

[Sym P. le]

Lomarandil, do you have a link to that video?

 

[Sym P. le]

From the above posted video link, an isolation of the collapse as an animated GIF (random screen grabs, so no guarantee of frame timing).

It looks as though the roof lost support at the connection to the north wall, falling straight down and initially pulling in the east and south street facing walls before pushing them out as the collapse progresses.

Included is a Google Maps Street View for detailed perspective of animation, and screen grab indicating vacant structural components at the north wall.

https://news.sky.com/video/mexico-c...g-sunday-mass-killing-several-people-12974802

Google Maps Street View
Google Maps Aerial View

 

[Sym P. le]

A step further east in Street View gives a more exact perspective of the above video frames.

A Street View time lapse indicates the original church structure in April 2009 (two frames), a north addition prior to August 2019, a roof in poor state of repair at least until June 2021, a new roof in the later half of 2021, a rather decent looking structure in January 2023.

Google Maps Street View
Google Maps Aerial View

 

[Sym P. le]

... that just looks like form marks to me.

Yes, I now see another image from Google Maps that shows clear form marks on the ceiling.

Are these some sort of tension bar?

From more imagery at Google Maps, I believe the bar is just a stage prop. I don't see any other transverse elements in any imagery to suggest they are used in this structure. Also, the stage lighting / sanctuary lighting is screened from the pews creating the stark light patterns seen in the imagery.

 

[Sym P. le]

I stand corrected on the cross ties. I didn't look closely enough but the Google images are clear. It looks like rebar.

And a better quality video on X-twitter

 

[Sym P. le]

A view across to the north wall.

infobae.com/mexico

And a 3D view derived from some screen shots.

 

[Sym P. le]

The area of the northwest corner of the sanctuary suffered disproportionately greater damage than the northeast end and pulled on the structural addition. This could get interesting.

milenio.com

 

[Sym P. le]

Upon closer inspection of the video frames, I can see the siding on the addition above the sanctuary being pulled west and the earliest puff of dust rising in the corner of the small crook in the addition. The sight line is consistent with the collapse initiating in the northwest corner of the sanctuary.

A few videos from inside the addition have been posted to Facebook so I've taken some screen shots of the relevant area showing the steel frame and one twisted element. I also note that a masonry support column for the original sanctuary structure has been pushed over in front of the twisted steel element.

 

[Sym P. le]

Not much rebar visible in the broken trough.

 

[Sym P. le]

A parting shot across the building to the proposed initiation site and a revisit of the 3D focused on the same area.

Now, aside from lack of rebar, how would this roof system come apart?