Building "Shaking" in Shenzhen

[Randy W]

Alert: Shenzhen Safety Alert Corrected Copy

from americancitizensinchina@state.gov

 

Security Alert -

Location: SEG Tower/Huaqiangbei Area, Shenzhen, Guangdong Province

 

Event: Following May 18, reports of shaking at the SEG Tower located in the Huaqiangbei (electronics market) area of Shenzhen, and the evacuation of people from the building and in the immediate vicinity, U.S. Consulate General in Guangzhou employees have been instructed to avoid the SEG Tower/Huaqiangbei area until further notice. 

 

The U.S. Consulate General in Guangzhou recommends that all U.S. citizens avoid the SEG Tower and Huaqiangbei area until further notice.

 

Actions to Take:

·         Monitor local and international media for updates.

·         Notify friends and family of your safety.

·         Use caution when walking or driving.

 

[Randy W]

from the Global Times

Shenzhen’s 355-meter skyscraper wobbles, evacuated and cordoned off

Quote

 

The bureau said Tuesday afternoon that it is probing why the SEG Plaza wobbled, which is a 355-meter-high iconic building in the city. It added that there was no earthquake striking the city or nearby areas on Tuesday.

At around 1pm on Tuesday, hundreds of people were seen running into the street near the plaza, and the video clips were among the most viewed on China's Sina Weibo on Tuesday.

It is reported that the plaza has been temporarily evacuated and now sealed off. Fire department and police are examining the case.

Swaying usually only occurs when there is an earthquake and that it would be abnormal for the SEG Plaza to wobble if there is no earthquake, Lu Jianxin, a senior engineer from China State Construction Engineering Corporation, told a local newspaper.

"Judging from what's published, this could be a sheer conincidence - resonance," Lu explained, noting that this is only his guess.

 . . .

The building stopped vibrating at 1:30 pm and no safety abnormalities have been found in the building's main structure and its surrounding area, the city's housing and construction bureau also said in a post on its official Weibo account later in the day.

Reiterating that there are no ground cracks, the bureau said that the building's interior steel structure and its decorative surfaces are in normal condition. The cause of the vibration is still being investigated, according to the bureau, noting that the building's main structure remains safe.

 

 

[Randy W]

 

[Randy W]

SEG Plaza is cleared of safety issues by local inspectors while US consulate warns citizens to stay away after mysterious shaking

• Real-time monitoring of the building’s vibration frequency, tilt rate and settlement degree found that they did not exceed official safety parameters
• Merchants were allowed to enter the SEG Electronics Market on Wednesday, but customers were still being denied entry

A photo posted on Chinese social media shows people in the street after they ran out of the SEG Plaza on Tuesday. The city’s government has said the structure is safe. Photo: Handout

from the SCMP

The Shenzhen housing and construction bureau commissioned multiple professional institutions to conduct real-time monitoring of the building’s vibration frequency, tilt rate and settlement degree from 9pm on May 18 to 3pm on May 19, and found them all to be within official ranges set by China’s safety bodies, according to the statement released on the official WeChat account of the Shenzhen government.

 . . .

Chinese media reported that employees at the city’s emergency management bureau said in an internal document that the shaking was possibly caused by a combination of factors, including wind, the subway line below the building, and temperature differences inside and outside the building.

[Randy W]

On May 20th, Shenzhen's third tallest skyscraper, the 356 meters tall SEG Plaza, shook once again for the third time after similar shaking on the 18th and 19th. 

On the same day, a number of SEG Plaza merchants said that around 12:30pm, the 35th, 55th, 60th and many other floors felt shaking, and security guards have informed merchants on higher floors to evacuate. 

There is also a video uploaded by netizens showing a number of large trucks carrying building materials into SEG Plaza. Various construction materials are also piled up on the ground floor of the building. 

The group said that according to the test data, everything is normal and do not exceed the corresponding limitations. 

Some netizens called into question the causes of shaking given by the experts. So why didn’t it shake before?

The construction quality of SEG Plaza has since become a hot topic of discussion.

356m Tall Skyscraper Shaking Again, Monitoring Data released, analysis of the causes of shaking

[Randy W]

Shenzhen’s Shaky Tower Is a Cautionary Tale
After decades of heedless growth, a reckoning may finally be at hand.

from Bloomberg

Quote

 

A decade later, the city was booming, and Shenzhen SEG Co. was keen to go even bigger. In 1996, the company went public and rolled some of the proceeds into SEG Plaza. Last week, Chinese media unearthed a report on the building’s construction authored by a (then) graduate student. She noted that “Shenzhen speed” wasn’t speedy enough for SEG Plaza: The tower was raised at a rate of one floor every 2.7 days. She also found that the building’s construction began before the design and review process was even complete, and that updated plans were delivered throughout the project, meaning that completed sections would often have to be reworked.

SEG Plaza wasn’t the only project to cut such corners. For years, Shenzhen’s contractors made cement with sea sand. It’s far cheaper than river sand, and for good reason: It corrodes the structural steel that holds up buildings. In 2013, the city identified 31 companies that had used sea sand in construction and suspended eight of them for a year — but it never identified any at-risk buildings. Perhaps unsurprisingly, building collapses are a regular, recurring tragedy in China.

If construction problems had impeded Shenzhen’s march to affluence, the government would’ve intervened decades ago. But the unvarnished truth is that China’s epic economic boom happened inside of poorly built offices and factories. In many cases, the relatively modest investment in infrastructure gave building owners and landlords little incentive to stick to a building’s original purpose. A few years after opening, for example, SEG Plaza became a global hub for trading cheap, used electronic components — rather than the new ones that the company had hoped to drive. Chinese traders in, say, New York might buy 5,000 used desktops from a Wall Street bank and ship them to south China. Within a couple of months, their semiconductors would be on sale in an SEG stall.

It wasn’t the kind of business that Shenzhen wanted to advertise to the world (when dignitaries were in town, the government would actually shut the plaza down). Its mere existence hinted at the city’s relatively flexible attitude to intellectual property. But over the years, the neighborhood surrounding SEG Plaza filled with malls also marketing used components to up-and-coming manufacturers who weren’t exactly scrupulous about patents and trademarks.

In recent years, it became obvious that SEG Plaza’s best days were behind it. Chinese consumers who once sought out the largely disposable electronics built from SEG’s inventories were moving up to better devices. When I first visited the tower in the mid-2000s, the dim 10-story mall at its base was a crowded and relentless warren of stalls, all packed with chips and computers for sale. In the last half-decade, the stalls have become increasingly populated with beauty products, electronic cigarettes and crypto-mining rigs. Shenzhen’s freewheeling days as an unaccountable manufacturer of low-cost goods are over. 

Also gone are the days when buildings like SEG Plaza could be erected at Shenzhen speed, and when used electronic marketplaces would dominate China’s biggest cities. In both cases, the country has moved on to better and more expensive things. Still, it won’t be easy to erase or forget the buildings and industries that paved the way to China’s current affluence. The swaying of SEG Plaza is just the most prominent reminder that the reckoning could be lengthy, and expensive.

 

 

[Randy W]

Tenants evacuated from Shenzhen’s swaying SEG Plaza skyscraper demand compensation as investigation into cause continues

• Many tenants selling electrical goods in Shenzhen’s fifth-highest tower want to be compensated for business disruption and early termination of their leases
• Mystery still surrounds the periodic trembling of the 72-storey tower after 10 days

Quote

 

In an internal notice to the tenants dated May 20 shared by the official news agency Xinhua, the building owner said no one would be allowed to enter until an investigation was finished, without giving an idea of the time frame.

The SEG Group has banned “all owners, merchants and tenants from entering or leaving the SEG Building and electronics market … [which] will open again after the relevant inspection work is completed”, the statement said.

The measure came into effect last Friday.
Ten days on, there is still no official explanation for the shaking and the tower remains closed.
The Shenzhen Housing and Construction Bureau has commissioned multiple professional institutions to monitor the building since the incident. Tests have found everything to be within official ranges set by China’s safety bodies, according to a statement released on the official WeChat account of the Shenzhen government.

 

 

[Randy W]

Chinese investigators announce cause of mysterious shaking in skyscraper

• Planned work includes removing antennas and repairing damage – but plaza will no longer be among Shenzhen’s 10 tallest buildings
• Property agent says the landlord may have to offer substantially discounted rent to get tenants back and restore confidence

It's not clear that this will be very re-assuring.

Quote

 

The main cause of mysterious shaking in the SEG Plaza in Shenzhen two months ago was a “vortex-induced resonance” from two long masts on top of the building, say investigators.

They said that while the building was safe overall, necessary rectification work – including removing the long antennas and repairing “damage accumulated” over the past two decades – was expected to take over a month, according to a statement on Thursday.

“The perceived vibration of the SEG Plaza building is caused by a combination of vortex-induced resonance of the rooftop masts and changes to the dynamic characteristics of the building,” it said.

Investigators conducted 63 vibration tests which showed that when the masts vibrated at a frequency of 2.12 Hz, “bending and torsion vibration” of the building occurred, the statement said.

The team of experts said the building had suffered “accumulative damage” over the past two decades, especially on floors connected to the rooftop masts. However, they stressed that such damage did not affect the building’s overall safety.