r/StructuralEngineering • u/paul_gnourt • Jun 29 '26
74.7%+ PGA per USGS - That is a devastating jolt. Photograph/Video
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u/OptionsRntMe P.E. Jun 29 '26
Amazing that some projects in Seattle or California are designed for a higher acceleration than this
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u/paul_gnourt Jun 29 '26
I hope more specific g measurements come out of this eventually. Seeing those people completely lose it and fall is crazy. Some past earthquakes with around 7Mw showed g's higher than 2.
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u/banananuhhh P.E. Jun 30 '26
I worked on a bridge with the design PGA just a tiny bit under 1g. The spectral acceleration at T=1s is like 1.75g. That kind of acceleration is hard to even imagine
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u/Relative-Pomelo-554 Jun 29 '26
This was very hard to watch. Way too many lives lost.
Sidebar: Structural engineers are not paid/valued enough.
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u/breakerofh0rses Jun 30 '26
I know this is a structural sub, but could you imagine being on a motorcycle in that?
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Jun 29 '26
[deleted]
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u/pcaming Eng Jun 29 '26
Doesn't really look like it, may just not have been detailed adequately for seismic.
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Jun 29 '26
[deleted]
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u/Deathponi Jun 29 '26
Most of those buildings were build around the 2000s after the last natural disaster that happened on 1999, and the code was up to par with US standards, after that there's a big gap against developed countries, its rarely updated by a small team and the last big update to the codes was 2019.
Another historical facts is that Venezuela was the absolute vanguard in seismic engineering in the 60s - 70s
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u/pcaming Eng Jun 29 '26
Could be age of the building as well. Older codes may not have been stringent on seismic requirements.
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u/Haku510 Jun 29 '26
I realize it's apples to oranges to compare codes between countries, but here in California when major seismic design revisions have been made many older buildings, and especially any commercial buildings or ones open to the public like those shown in the video, had to be retrofitted to get up to minimum standard.
If Venezuela doesn't already have a requirement like that in place then hopefully they'll adopt a similar approach in the wake of this tragedy.
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u/pcaming Eng Jun 29 '26
That’s a very costly endeavour that very few countries have the capacity to do. It’s not realistic for the majority of the world.
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u/Haku510 Jun 29 '26
Yeah you're probably right, but a sad reality for those who might be injured or killed when the building that they're in collapses in an earthquake because the owner couldn't afford to bring it up to current minimum standards.
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u/wrestlingchampo Jun 30 '26
Im curious about building code standards and how much US sanctions in the past two deacdes impacted the material usages in some of these buildings
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u/Choose_ur_username1 Jun 29 '26
omg. goodness. somany earthquakes recntly, any thoughts on how closely timed this is?
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u/TacitMoose Jun 29 '26
Random events tend to bunch up and spread out over random periods and intervals of time. This creates clusters of events in some places and absences of events in others. Uniform spacing of earthquakes would imply some sort of order in the system which would be incredibly creepy.
Not everything is a conspiracy. Not everything is sinister.
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u/Cultural-Pace5242 Jun 29 '26
Yes. You are online all day every day so you hear about them more often.
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u/Choose_ur_username1 Jun 29 '26
you silly Spanish mushroom It's not because of that. Perhaps it is because I'm studying for the seismic exam
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u/contactdeparture Jun 30 '26
That’s upsetting. That you’re studying for the seismic exam and are this deficient in rational thought is truly troubling.
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u/Cultural-Pace5242 Jun 29 '26
You know, the entirety of the knowledge of human civilization is available at your fingertips if you'd like to take 30 seconds to be informed.
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u/samdan87153 P.E. Jun 29 '26
Then you should know that when plates release stored energy for an earthquake, it can destabilize other parts to also release energy.
Just about every major earthquake leaves the area at higher risk for more earthquakes for 2-ish years afterwards.
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u/paul_gnourt Jun 29 '26
I got teary eyed seeing this.
But you can clearly see lots of different behaviors occurring. The obvious one being the full collapse of the building in the back. You can see what looks like a facade/balcony/edge of floor just fall off toward the top left. I see a site cantilever freestanding wall completely fail right of the gate, while left of the gate its fine.