What would cause a building to shake?

[Mark Hennebury]

So a skyscraper in China starts shaking for no apparent reason. Anyone have any ideas what would cause it?

Thousands of shoppers in the southern Chinese city of Shenzhen fled the vicinity of a 957-foot (291-meter) skyscraper Tuesday, after it inexplicably began swaying.

https://img-s-msn-com.akamaized.net/tenant/amp/entityid/BB1gTgbN.img?h=810&w=1438&m=6&q=60&o=f&l=f

Follow the link for the story.

https://www.msn.com/en-ca/news/world/shenzhen-seg-plaza-people-flee-in-panic-as-skyscraper-wobbles-in-china/ar-BB1gTeke?ocid=sf


https://www.youtube.com/watch?v=MwFg0J1IfQs

[Peter Kelly]

Seems like a combination of factors likely due to not having a mass dampening system installed: https://www.theguardian.com/world/2021/may/20/china-skyscraper-wobble-shenzhen-winds-rail-lines-weather-reports

Interestingly, the wobbling movement was vertical rather than lateral.

[Edwin Santos]

With a building that tall and narrow, it could be related to vortex shedding. Maybe harmonics too. Usually the designers test scale models of the design in a wind tunnel to identify the issues. Very interesting area of structural engineering.

See here:


https://www.youtube.com/watch?v=ebx5Y5qOmTM
https://www.youtube.com/watch?v=ebx5Y5qOmTM

[Adam Herman]

i would guess some kind of harmonic issue as well. interesting. also, china builds these things as fast as possible with little regard to proper engineering.

[Mark Hennebury]

I worked at a engineering firm that did wind tunnel testing on tall buildings, i built the models that were tested in the wind tunnel. We built scale models out of Balsa wood and printed plastic models which we installed hundreds of tiny tubes that were connected to sensor to measure wind pressure at various places. We also built a scale model of the surrounding city scape to place the new design in, The whole setup was placed in the wind tunnel and tested.

The reports on this building have said that there was no wind issue. They said that there was only a slight breeze. It will be interesting to see what the attribute the cause to.



With a building that tall and narrow, it could be related to vortex shedding. Maybe harmonics too. Usually the designers test scale models of the design in a wind tunnel to identify the issues. Very interesting area of structural engineering.

See here:


https://www.youtube.com/watch?v=ebx5Y5qOmTM
https://www.youtube.com/watch?v=ebx5Y5qOmTM

[Mark Hennebury]

Shenzhen is a new city with a lot of skyscrapers.

458521

https://www.cnn.com/style/article/shenzhen-skyscraper/index.html

https://shenzhenshopper.com/2731-future-shenzhen-the-new-wave-of-skyscrapers.html





i would guess some kind of harmonic issue as well. interesting. also, china builds these things as fast as possible with little regard to proper engineering.

[Doug Garson]

+1 on the wind harmonics, the Tacoma Narrows bridge was brought down by 40 mph winds in 1940.https://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge_(1940)

[Mark Hennebury]

The building has been there for 21 years.!

[Bill Dufour]

In 21 years other tall buildings have gone up and disrupted airflow around the older one.
Bill D

[Andrew Hughes]

I think it’s payback from Mother Nature for blaming the corona virus on her.
Everyone know it was gain of function research.

[John K Jordan]

The reports on this building have said that there was no wind issue. They said that there was only a slight breeze. It will be interesting to see what the attribute the cause to.


Too many wild parties at one time.

New round of nuclear testing.

Tiny black hole hit the earth.

High school prank: "Ok, on the signal we all run to the other side of the building then run back."

A record number of cicadas coming out of the ground.

Elon Musk drilling another underground tunnel.

Space aliens approaching. Video at 6.

[Mel Fulks]

The tremor might just exist in the hands of the camera people. “Camera- rowdyree”

[Warren Lake]

likely too many Yutes inside dancing all at once making Tik Tok videos

[Kev Williams]

so I've read above China builds 'as fast as possible with little regard to proper engineering', and 'the wobbling movement was vertical rather than lateral'...

So, hasn't anyone else's house 'settled'?
458539458540
-notice the 2"+ rock under the back wheel of the BBQ to level it? ;)

Lax engineering in the foundation deptartment and vertical wobbling, both are signs the thing's just moving farther down into the ground a bit...

[Jerome Stanek]

Street traffic could account for the shaking

[Jim Matthews]

Even money says the substructure isn't as designed, likely without pretensioned concrete pilings. There's no downside to cutting corners in Chinese construction and maintenance is a passe Western idea.

[Mark Hennebury]

The tower comprises a steel-reinforced concrete core with external steel tube columns filled with concrete. It has four basement levels.[4] (https://en.wikipedia.org/wiki/SEG_Plaza#cite_note-fireperformance-4)
It was constructed for Seg Plaza Investment and Development with investment from the Shenzhen SEG Group Co. Ltd. The tower was designed by Chinese architecture firm Hua Yi Designing Consultants Limited (Chinese (https://en.wikipedia.org/wiki/Chinese_language): 华艺设计顾问有限公司).[5] (https://en.wikipedia.org/wiki/SEG_Plaza#cite_note-tallbuildingsbook-5)

The octagonally-shaped building is the tallest in the world to be built with concrete-filled steel tubular columns.


Height: 356 meters / 1,168 feet


Preliminary inspections by on-site experts found that there are no safety-related abnormalities in the building’s main structure or surrounding environment, the government said in the statement.
There were no cracks found in the ground nearby, the interior steel structure was normal, and curtain wall panels and other decorative surfaces did not fall off or sustain damage, it added.


It seems to stand quite high above all the surrounding buildings, it seems strange that a light breeze would do anything to it.

458572

An interesting article about the construction industry in Shenzhen.

https://www.bloomberg.com/opinion/articles/2021-05-24/shenzhen-s-shaky-tower-is-a-cautionary-tale

[glenn bradley]

Obviously some western propaganda.

[Frederick Skelly]

[QUOTE=Mark Hennebury;3123140]An interesting article about the construction industry in Shenzhen.

https://www.bloomberg.com/opinion/articles/2021-05-24/shenzhen-s-shaky-tower-is-a-cautionary-tale[FONT=Merriweather]

That was an interesting article. He claimed building collapses occur regularly in china. I didnt know that. He also said concrete made with sea sand corrodes steel. Does anyone understand why? I'd previously thought sand was not permeable, and wouldnt soak up chemicals from salt water. But I guess that must be wrong?

Fred

[Doug Garson]

Don't think the salt is absorbed by the sand, it just coats the sand. If it was thoroughly rinsed, there would be no problem.

[Mark Hennebury]

I read somewhere today, that the swaying could be caused by a combination of wind, street traffic and a subway. Still it's all quite fascinating and i am interested to know what actually caused it.

That Bloomberg article was interesting, hard to know if its all true, same with everything these days.

[Frederick Skelly]

Don't think the salt is absorbed by the sand, it just coats the sand. If it was thoroughly rinsed, there would be no problem.

Thank you. That makes far more sense to me. :)

[Clifford McGuire]

What can be done about it?

[Lee DeRaud]

I blame graboids...isn't a new 'Tremors' sequel due out soon? :)

[Jim Koepke]

i would guess some kind of harmonic issue as well. interesting. also, china builds these things as fast as possible with little regard to proper engineering.

Hi Adam, do you have links to articles on this?

A quick search indicated that innovative building techniques have sped up construction but it also indicates they are not cutting safety, engineering or disregarding international building standards and regulations:


“I think this goes back to an innovative form of modular Lego like construction,” Alastair Campbell, Investment Manager-Asia Pacific at Kames Capital told CNBC via email.

“This is not a case of a Chinese builder throwing up a building as fast as possible in order to make a quick buck and a sign of lax building regulations. Rather the intention was to demonstrate an efficient building technique, after all the Chinese have built a lot of huge apartment blocks over the last 20 years.”

However, such speed has raised questions on the buildings’ sustainability, longevity and safety even though some analysts have said that the construction companies follow international building standards and regulations.

“Undoubtedly, there are poorly constructed and designed buildings in China, particularly due to historically poor application and oversight of planning and building laws. However, I suspect that the application of laws has probably been tightened and standards enforced since the anti-corruption drive initiated by President Xi Jinping in 2012. The penalties for breaching building laws can be severe,” Kames’ Campbell told CNBC.

This was about a 57 story building that was put up in 19 days, found at > https://www.cnbc.com/2016/08/23/a-skyscraper-in-two-weeks-does-chinas-building-boom-hide-bigger-problems.html

The article suggests the current problem in China caused by the high speed of construction is an over supply of vacant floor space.

NOTE: this article is from 2016.

jtk

[Jim Matthews]

My point got buried in the discussion.

Something changed, as this swaying was not noted before. Absent seismic activity, or lateral loads from wind all that remains is either the occupants or foundations.

My bet is on what can't be seen, below ground.

The CCP is not known for transparency regarding public works or robust regulation of construction materials.

https://www.wired.com/2013/03/poor-quality-chinese-concrete-could-lead-to-skyscraper-collapses/

[Adam Herman]

Hi Adam, do you have links to articles on this?

A quick search indicated that innovative building techniques have sped up construction but it also indicates they are not cutting safety, engineering or disregarding international building standards and regulations:


jtk

https://www.youtube.com/watch?v=q00nTSAcMhs

https://www.wired.com/2013/03/poor-quality-chinese-concrete-could-lead-to-skyscraper-collapses/
plenty of others.

its really down to their contracting and administration, where its better to be corrupt than do the right thing. just because the building plan says a thing must be some spec, does not make it so in the real world.

just noticed i grabbed the same article as above.

[Kev Williams]

. just because the building plan says a thing must be some spec, does not make it so in the real world.

Reminds me of friend of mine, he's construction designer & welder who helped build the Utah Jazz Delta Center arena; he explained 'the real world' issues that came with that project, the biggest one being that when the end of the building was about to be connected up to the beginning, they found that the building's end was 11" shorter than the beginning... Don't know exactly how they dealt with that but 'that's what trim is for' probably came into play ;)

[Mark Hennebury]

Corruption is not just a Chinese problem.
Anywhere there are people there is corruption.
My Father was a government construction building inspector for the Public Works Department
They needed inspectors, and some of the inspectors needed inspectors, and some of the department managers needed inspectors... there were often scandal's and arrests in big government contracts.

https://en.wikipedia.org/wiki/Big_Dig

The Big Dig was the most expensive highway project in the US, and was plagued by cost overruns (https://en.wikipedia.org/wiki/Cost_overruns), delays, leaks, design flaws, charges of poor execution and use of substandard materials, criminal arrests,[2] (https://en.wikipedia.org/wiki/Big_Dig#cite_note-2)[3] (https://en.wikipedia.org/wiki/Big_Dig#cite_note-3) and the death of one motorist.[4] (https://en.wikipedia.org/wiki/Big_Dig#cite_note-The_Associated_Press-4) The project was originally scheduled to be completed in 1998[5] (https://en.wikipedia.org/wiki/Big_Dig#cite_note-5) at an estimated cost of $2.8 billion (in 1982 dollars, US$7.4 billion adjusted for inflation as of 2020).[6] (https://en.wikipedia.org/wiki/Big_Dig#cite_note-inflation-6) However, the project was completed in December 2007 at a cost of over $8.08 billion (in 1982 dollars, $21.5 billion adjusted for inflation, meaning a cost overrun of about 190%)[6] (https://en.wikipedia.org/wiki/Big_Dig#cite_note-inflation-6) as of 2020.[7] (https://en.wikipedia.org/wiki/Big_Dig#cite_note-7)The Boston Globe (https://en.wikipedia.org/wiki/The_Boston_Globe) estimated that the project will ultimately cost $22 billion, including interest, and that it would not be paid off until 2038.[8] (https://en.wikipedia.org/wiki/Big_Dig#cite_note-8) As a result of a death, leaks, and other design flaws, Bechtel (https://en.wikipedia.org/wiki/Bechtel) and Parsons Brinckerhoff (https://en.wikipedia.org/wiki/Parsons_Brinckerhoff)—the consortium that oversaw the project—agreed to pay $407 million in restitution and several smaller companies agreed to pay a combined sum of approximately $51 million.[9] (https://en.wikipedia.org/wiki/Big_Dig#cite_note-9)

[John K Jordan]

...
Anywhere there are people there is corruption.
My Father was a government construction building inspector for the Public Works Department...

I've been a concrete inspector, in-shop steel fabrication inspector, bridge and building steel construction inspector in the field, NDT tech and inspector (xray, mag particle, ultrasonics, dye penetrant, etc), and welding inspector (and I may have forgotten some others).

At every step there was opportunity to streamline the work by "overlooking" defects in exchange for money or other benefits, ESPECIALLY in nuclear power plant construction where 10s of thousands of $$ were on the line if a single defect deep inside a heavy-wall pipe weld caused it to be rejected. Even the concrete business could get testy: we once rejected the concrete on a foundation on a 1/2 completed parking garage based on lab cylinder compression tests - the concrete had to be torn out and replaced at great expense. Some contractors seemed frustrated (actually really ticked off) I and others I worked with refused to play the game. I knew an inspector or two I wondered about...

JKJ

[Frederick Skelly]

Good on you John! Your courage and integrity may well have saved lives.

Not saying it's ok by any measure, but corruption in civil works projects is an ancient vice. I've read of cases in Rome and I'll bet there were cases in Greece, Egypt and Babylon.

[Mark Hennebury]

People talk about all of the reports of shoddy construction from China, but China probably does ten times more construction projects than any other country, and the do them ten times faster.

Corruption is everywhere, you don't have to look far.

My father got a lot of pressure to sign off on a construction project, that he was supposed to inspect, but it was done before he got there; a concrete pour, if i recall. He refused to sign off because he didn't get to inspect it, and the job was halted. He got called in the bosses office and "pressure/threatened" Meanwhile a few guys in the same department were arrested for receiving gifts and paid vacations from contractors.

Funny that you mentioned Nuclear Power Stations. My father also worked at Dungeness Nuclear Power Station in the south of England way back, we had bunches of concrete core samples, probably still a few of them at the old house.

We are all human, and temptation is strong. Pressure immense. Turn a blind eye, what's the harm? look at the rewards for you and your family. It's a tough row to hoe being honest. it takes gut's to take a stand, especially when you see what it will cost you. There are no rewards for honesty. A conscience is the most expensive thing that you will ever own.
The best chance that we have is for us all to cultivate a conscience, but in the meantime, checks, balances and consequences will help.


I've been a concrete inspector, in-shop steel fabrication inspector, bridge and building steel construction inspector in the field, NDT tech and inspector (xray, mag particle, ultrasonics, dye penetrant, etc), and welding inspector (and I may have forgotten some others).

At every step there was opportunity to streamline the work by "overlooking" defects in exchange for money or other benefits, ESPECIALLY in nuclear power plant construction where 10s of thousands of $$ were on the line if a single defect deep inside a heavy-wall pipe weld caused it to be rejected. Even the concrete business could get testy: we once rejected the concrete on a foundation on a 1/2 completed parking garage based on lab cylinder compression tests - the concrete had to be torn out and replaced at great expense. Some contractors seemed frustrated (actually really ticked off) I and others I worked with refused to play the game. I knew an inspector or two I wondered about...

JKJ