At 11:55 on May 20, the shaking occurred again in Shenzhen Sage Building.
Wuhan Morning News reporter saw in the building 26th floor, there are office staff to take the elevator down to evacuate. In the elevator, a woman said that the shaking lasted almost a minute, “longer than yesterday”.
Subsequently, she showed a video to the reporter. In the video, the glass teapot of water kept shaking.
When the shaking occurred, in the building on the 6th floor, it was a different story. The merchants here are still calmly working, and no signs of evacuation, evacuation radio sounded when several merchants are enthusiastically discussing the sale of goods.
“Shaking are used to it.” A man said.
In the following hour, the building shakes twice more, the reporter felt a clear sense of vertigo.
In the afternoon, a staff member of the Sage Building property told reporters that all office staff located in the upper floors of the building have been evacuated, “the building is currently only out of all personnel.
Sage building internal monitoring
20, is Shenzhen Huaqiang North Saige building sudden shaking third day, the weather is clear, occasionally breezy. The weather forecast shows that today the maximum wind level 3.
At around 10:00 am, the reporter saw in the Sage Building Gate 1, the site is still closed management, there are staff in front of the gate to check the identity of people entering and leaving.
Around the building, surrounded by a circle of police cordon, there are security personnel in persuading the masses close to the building.
The reporter found at the east gate that the previously stacked steel pipes, barbed wire and wooden boards had been removed, and no protective shed was built at the scene.
The first day around 9:00 pm, the reporter had seen here, several large trucks loaded with steel pipes, boards and barbed wire parked at the door, a crane is constantly unloading.
Site workers had told the Wuhan Morning Post reporter, they will begin to erect a protective shed around the Sage Building, “but the leadership is still discussing.”
Inside the building, some merchants from the 1st to the 10th floor have been in the field to return to work. Here is located in the lower floors of the building, for the store area, a large number of stores selling various types of electronic products gathered here.
Merchants keep packing and loading goods, very busy. A merchant said that today there are orders, need to ship, must come to deal with. But most of the merchants are currently closed, the goods in the counter packed empty, the door is closed.
The 10th floor up for the office area. That morning, the reporter randomly visited several floors, were found, each floor has office staff. A woman said that they just finished property release application form, the property does not allow to stay in the building for a long time.
In a place located in the building’s upper floors, the reporter also found that the building installed the relevant detection devices, and posted “monitoring equipment, do not touch” signs.
In the central floor, the reporter also found a similar marker points.
Monitoring equipment and shaking
Around 11:55, the building suddenly began to shake, the reporter then evacuated.
The reporter saw that the elevator was crowded with evacuees, a woman said that she was dizzy for a long time. “The water in the teapot on the table has been shaking non-stop for longer than yesterday.”
After the incident, Wuhan Morning Post reporter came to the 6th floor, where the merchants did not evacuate signs, most of them still calmly work.
Several merchants gathered around the counter to discuss the shaking just now, a woman said that just now she felt strong and dizzy. But she had a relaxed expression and a calm look.
Reporters asked why they did not run away at that time, a man next to her said, “the two days at this point in time every day shaking, are used to it.” And another woman said, “they are working, life is not worth it, there is no need to run.”
The reporter first personally felt the building shaking is in 25 minutes. Around 12:20 p.m., a merchant pointed to the water fountain bucket and said loudly, “Look, it’s shaking again.”
Subsequently, several merchants went around, the bucket, the water was clearly visible in the left and right shaking. At this point, the reporter felt, a little dizzy, slightly uncomfortable. Close to the wall, it is clear that you can feel the signs of shaking.
Subsequently, the radio issued a reminder, asking people not to stay in the building, quickly evacuated. At this point, the reporter saw that the merchants located on the 1st to 10th floors did not evacuate signs.
The third shaking occurred at about 12:55, the reporter first felt a pang of nausea, a strong sense of vertigo on the chest, and then clearly felt the floor under the feet in motion. On the side, the metal door of the fire hydrant kept swaying from side to side, visible to the naked eye.
In the afternoon, a staff member of the property told reporters that the current office staff located in the upper floors of the building has been evacuated, “all personnel in the building only out of the building.
Subsequently, the reporter returned to some of the floors previously visited to see that all personnel above the 10th floor have been evacuated, the morning office, the company has also locked the door.
And in the 69th floor, several technicians are constantly debugging equipment. A side of the property staff told reporters that these are installed to monitor the device.
“The building has shaken a few more times today, always panicked working inside, and I do not know how it will be handled.” He said.
Sage Building
Tremors
Saige Building is located in the southernmost side of Huaqiang North Street, the building’s total height of 355.8 meters, a total of 79 floors, 75 floors above ground, 4 underground, with a total construction area of 170,000 square meters, is currently the world’s tallest steel pipe concrete structure building, is now the fifth tallest building in Shenzhen.
The lower 10 floors of the building are tetrahedral, with a podium and mainly stores. The upper 60 floors are cylindrical, mainly office buildings, with many companies distributed among them.
The building towers into the clouds, in the surrounding tall buildings, but also obviously to be a large part of the higher.
At around 1:00 pm on the 18th, the building suddenly shook and about 15,000 people flocked to evacuate from the building. Subsequently, the relevant departments issued a briefing that there was no earthquake in Shenzhen that day, and there were no high winds around the Sage Building, the maximum wind force of 5 that day.
Experts at the scene did not find the glass curtain wall off and ground cracks, the main structure of the building and the surrounding environment was not found to involve safety abnormalities.
According to media reports, this is not the first time that the Sage building shaking.
An insider from the Sage Group said, “six or seven years ago, when the typhoon also shook once, but not so obvious, and then also returned to normal. At present, it is the reason of ‘tremor’, the building is still safe.” .
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The “shaking” of the Sage Tower: once created 2.7 days to build a floor of “Shenzhen speed”
In the afternoon of May 18, the 355-meter-high Shenzhen Huaqiang North Saige Plaza building suddenly shaking, merchants and citizens running emergency evacuation. Subsequently the building shaking video on the Internet screen, and on the microblogging hot search.
According to the official notification issued by the relevant departments, there was no earthquake and typhoon in Shenzhen that day. Experts at the scene did not find the glass curtain wall off and ground cracks, the preliminary determination of the “tremor” caused by the shaking, the main structure of the building and the surrounding environment is not found to involve safety abnormalities.
May 19, the “Daily Economic News” reporter came to Huaqiang North again to learn that the whole street has resumed the prosperity of the past, but the Sage Building pulled up a cordon, although not completely shut down, but currently only allow the 1 ~ 10 floor of the business to pick up goods, delivery.
May 19, Huaqiang North street. Photo credit: Liu Ling, every reporter
In the back door of Saige Building, a large trailer full of steel pipes and protective nets and a crane were parked, and a survey team from CMTC was monitoring the building. Site staff told reporters that Shenzhen has set up an on-site command, relevant leaders and experts are still upstairs for discussion, further analysis of the causes and the development of emergency treatment plan.
For the outside world on the Saige building is not installed “dampers” questions, Saige Group insiders told reporters that the construction of the Saige building earlier, when the structural design is not needed dampers. At present, experts recommend the installation of dampers, but the final plan has not yet come out. “Six or seven years ago when the typhoon also swayed once, but not so obvious, after that also returned to normal. At present, it is the reason of ‘tremor’, the building is still safe.” Sage Group insiders said.
After the “shaking” of the Sage building, there are comments that the recent surge in cryptocurrency, Huaqiang North bosses in the stalls digging Chia coins, thousands of mechanical hard disk vibration together, causing the building resonance. In this regard, a mining store owner Li Cheng (a pseudonym) told reporters that this is completely nonsense: “Mining requires mining machines to run 24 hours a day without power, the Sage market will lose power at night, it is simply impossible to mine. They see some stalls have mining machines running, just the store in the measurement machine or P plate.”
The day after the “shake”
These two days, although the Sage building has not resumed business, but downstairs there is a group of “look up”, head up, with cell phones to shoot this “shaking” on the hot building.
A property manager of the Sage Building revealed to the “Daily Economic News” reporter that the main structure of the building is safe due to the preliminary identification of experts as “tremor” caused by the shaking, so merchants can still go in and out to pick up goods. Mr. Wu (pseudonym), who pulled a cart of goods out of the building, told reporters that he could go upstairs to get something after registering at the door, but the front door only allows merchants from the 1st to the 10th floor to go up and get it, not higher, “to take the goods out a little more at ease”.
May 19, the door of the Sage Building. Photo credit: Liu Ling, every reporter
However, a seller of electronic products, Mr. Liu told reporters that the market semi-closed state more or less impact on business, just let the merchants in the delivery of goods, guests can not go upstairs. Sage building near the staff of the Yuan Tong Express said, “these two days are not much express, the building is not open yet, there is no business. It may also affect several days. The reporter entered the Sage Building and saw that half of the businesses from the first to the fourth floor have closed their stores, and some of the remaining businesses packaged and shipped in front of the stores. In a mining machine store door, two sales people are assembling mining machines. A salesperson told reporters that because most of their business is done online, basically the mine bosses these old customers, so the building semi-closed did not affect them too much, is assembling the mining machine is anxious to send out.
Subsequently, the “Daily Economic News” reporter came to the back door of the Sage building, saw a large trailer and a crane parked in front of the door, the trailer is loaded with steel pipes and protective net. A site staff told reporters that steel pipes and protective nets are used to strengthen the outer glass curtain wall, is still waiting for the program. However, on May 20, the director of Sage told reporters that the steel pipe on the trailer has been pulled away, temporarily do not need to use.
In the Saige building office building entrance, a number of security guards pulled up a cordon, do not allow non-staff to enter, the staff told reporters that Shenzhen has set up on-site command, relevant leaders and experts are still upstairs to discuss, further analysis of the causes and the development of emergency treatment program.
May 19, the back door of the Sage Building. Photo source: Liu Ling, every reporter
Ltd. (hereinafter referred to as CMCR) survey team also mapped different angles around the building, mapping staff while measuring and recording data, a surveyor told the Daily Economic News reporter, according to (that) afternoon of continuous monitoring, the building’s monitoring results are nothing wrong.
At 22:25 on May 19, the official micro-blog of “Futian Release” released the latest information, saying that entrusted by the Shenzhen Housing and Construction Department, from 21:00 on May 18 to 15:00 on May 19, a number of professional organizations to monitor the vibration, tilt, settlement and other conditions of the Saige Building in real time, the three indicators are far less than the norm. The three indicators are far less than the permitted values, and the monitoring data do not show any abnormalities.
Among them, the maximum acceleration of vibration on the 69th floor of Saige Building occurred at 13:51 on the 19th, which was less than the requirement of “Technical Regulations of Concrete Structure of High-rise Building-JGJ3-2010” about the wind vibration acceleration limit of 0.25m/s2 at the top point of office and hotel, and the monitoring amplitude of two institutions were 0.045m/s2 and 0.044m/s2 respectively.
In addition, the tilt rate of Saige Building was measured by Shenzhen Housing Safety and Construction Engineering Quality Inspection and Appraisal Center, and the measurement results showed that the tilt rate was between 0.01% and 0.02%. According to the Building Foundation Design Code, the tilt rate measurement result is far below the code standard (<0.2%). The settlement monitoring results of Sage Building are between -0.05mm~0.00mm, with stable change values and stable building settlement.
In other words, the continuous monitoring results of professional institutions show that the tilt rate and other monitoring results of Saige Building are in line with the code standards and the main structure of the building is safe. “Futian release” again said that the specific reasons for the vibration is being further verified, the relevant situation will be informed in a timely manner.
In accordance with the May 19 afternoon reporter was informed of the “emergency information special report” file, the provincial and municipal experts, the preliminary view: First, the Shenzhen Sage building is up and down trembling rather than left and right swing; Second, the cause of trembling is a variety of factors coupled, mainly the impact of wind, and subway operation (two subways from downstairs) and the impact of temperature (the last two days the temperature rose, the temperature difference of 8 degrees, the impact on the steel structure Thirdly, the main structure of Sage Building is safe, the internal structure is solid, and various ancillary facilities are intact.
2.7 days a floor, is the quality over?
Public information shows that the Sage Plaza building is located in the busy Shennan Middle Road and Huaqiang North Road intersection, completed in 1999. The total height of the building is 355.8 meters, with 79 floors, 75 floors above ground and 4 floors underground, with a total construction area of 170,000 square meters.
It is worth mentioning that the Saige Building was once the third tallest building in Shenzhen and one of the tallest steel pipe and concrete buildings in the world, which also created the “Shenzhen speed” of one floor in 2.7 days.
After the public attention caused by the shaking of the Saige Square, a thesis on the construction of the Saige Square many years ago was also turned up, saying that the Saige Building was “designed and constructed at the same time”, the thesis was written by Jin Dianqi, who was studying for a master’s degree at Huazhong University of Science and Technology.
Jin Dianqi’s thesis was titled “Shenzhen Saige Plaza Construction Project Analysis”, in which he pointed out that the construction process of the Saige Building had “failed to provide complete construction drawings when bidding for the general contractor for the whole project after the foundation was completed. But the foundation part has invested more than 50 million in the early stage, if the stoppage of work and other drawings will certainly cause the financial cost of the invested funds to increase, the arrow is on the string, had to send. So in a hurry, the project was tendered with some structural drawings of the podium for general contracting.” The paper also pointed out that the tender was invited, and the general contractor was also determined, but one step was slow, and the construction was often stopping and waiting for the drawings and reworking after construction according to the drawings, which led to many unnecessary disputes and increased the project cost. This phenomenon of designing and constructing at the same time has continued until the structural engineering of Sage Plaza was completed.
The paper also mentioned that after the steel structure was topped out on April 8, 1999, the construction of the antenna part was not completed until September 30 of the same year. When everyone was relaxed and happy to celebrate the 50th anniversary of the founding of New China, the ground pedestrians found that the antenna of Saige Square was swaying violently, at that time Shenzhen was windy and sunny, only breezy, it turned out that the antenna’s design calculation error caused resonance.
At that time, the construction and design party immediately called all the people, in time to set up safety facilities, day and night to cut the top 26 meters, lift the danger. After recalculating the installation up 13 meters, and made local modifications.
Based on the content of the paper, a number of netizens asserted that the shaking of the Sage Plaza may still be linked to the foundation quality problems.
Li Yong, deputy general manager of China Construction Group, said in an interview with the Daily Economic News that the design of high-rise buildings is allowed to have amplitude, each building situation is different, the specific parameters to be determined by the design unit. In his opinion the first important thing is to study what the source of amplitude is, whether it exceeds the design limit, “there is no quality problem is not just say”.
It is understood that Jin Dianqi is currently the director of operations of the Shenzhen Institute of Urban Public Safety Technology, Shenzhen City Security Softcom Technology Group Limited (hereinafter referred to as City Security Softcom) chairman. For the content of the paper, “Daily Economic News” reporter called City Security Softcom, the other side said that for the time being do not accept interviews.
Red Star News reported that the paper’s instructor Zhang Zigang said that the author has ideas, but does not represent science. According to Zhang Zigang, Jin Dianqi was majoring in business administration, not architecture, but at the time she had some ideas, and not to say that the authority.
Deep Sage director secretary Peng Aiyun said in reply to the Daily Economic News reporter interview, at present, the building body was not found to be a safety hazard, online many self-media to attract attention, released a lot of inaccurate information, causing social panic.
For this building body shaking led to the closure of business, deep SAGE will compensate the tenants? The building body shaking, the Sage Plaza late rental income and brand whether it will have an impact? Peng Aiyun said, for the time being, not, at present (Sage Plaza) in normal use, 19 building office and business personnel are still in and out of normal, only in the detection and monitoring process, in order to ensure the accuracy of the detection and monitoring work, to do the appropriate protection.
Is it necessary to install dampers?
In the document of the “Special Report on Emergencies Information”, a key word is mentioned – dampers. The document said that the Sage Tower was not installed with dampers, and experts suggested that the next step could be to consider installing dampers to improve wind and earthquake protection and comfort.
Damping is a physics term that refers to the attenuation of force and dissipation of energy. The so-called dampers, is placed on the structural system can provide resistance to movement, dissipation of motion energy of special components device.
The specific principle is that the damper adjusts its own frequency close to the control frequency of the main structure, and when the main frequency of the main structure is excited by the wind force, the damper will resonate with the main structure in the opposite direction due to the inertia of the oscillator and the return force generated by the spring. In the vibration process, part of the energy on the main structure will be converted into the kinetic energy of the damper oscillator, part into the elastic potential energy of the spring, while the remaining part will be dissipated by the damper to play the effect of weakening the vibration of the main structure.
As for the role played by dampers in super tall buildings, a professorial senior engineer of Xiamen Construction Bureau shared by Mingyuan Real Estate Research Institute said that super tall buildings are too large in height to width ratio and too soft in structure, and it is difficult to effectively change the self-vibration frequency of the structure only through structural design adjustment. Especially for steel buildings, the damping is small, and it is necessary to set wind dampers in some special parts or set damping walls, eccentric supports, flexural restraint supports and other energy-consuming elements to achieve the purpose of reducing wind-induced effects.
Generally speaking, most of the tall buildings over 300 meters are now installed with dampers. It is understood that the main body of the Taipei 101 building, completed in 2004, is the first Chinese tall building installed dampers, in the building’s 87 to 92 floor hanging a large golden ball, which weighs 660 tons, 5.5 meters in diameter, can help the building in a 12-magnitude typhoon shaking no more than the normal magnitude.
In addition, the new domestic tall buildings in recent years, such as the Guangzhou Tower, Shanghai Center Tower, Shenzhen Ping An Financial Center are installed dampers. A building industry insiders who do not want to be named told reporters, Guangdong coastal typhoons are high, super tall building design, especially to consider the resistance to wind loads, the use of reasonable, conducive to reducing the wind resistance of the building shape design structure, while increasing the wind dampers.
For the outside world on the Saige building is not installed “dampers” of doubt, Saige Group insiders told reporters, Saige building construction time earlier, when the structural design is not needed dampers. At present, experts recommend the installation of dampers, but the final plan has not yet come out, whether the final installation is still uncertain.
The insider also told reporters, “six or seven years ago when the typhoon also swayed once, but not so obvious, and then also returned to normal. At present, it is the preliminary conclusion of the experts that the ‘tremor’ causes the building to shake, just like the Humen Bridge before, the building is still safe, the specific reason for the ‘tremor’ is still being further verified”.
The shaking has nothing to do with virtual currency mining
After the “shaking” incident in the Sage Building, there was a lot of discussion online about the cause of the shaking. There are comments that because of the cryptocurrency surge, Huaqiang North bosses in the stall to dig Chia coins, hard disk disk high-speed rotation, the number of hundreds of thousands into tens of thousands, so many hard disk high-speed rotation at the same time, coupled with the northern hemisphere ground rotation bias force to the right, resulting in the resonance of the Sage building.
In this regard, a mining machine store owner Li Cheng (a pseudonym) told reporters that this is completely nonsense: “mining needs mining machine twenty-four hours of non-stop power operation, the Sage market will lose power at night, simply can not mine. They see some stalls have mining machines running, just the store is measuring the machine or P disk.”
On May 19, the mining machine stores in Huaqiang North. Image source: per reporter Liu Ling photo
Shenzhen Huaqiang North is one of the world’s largest mining machine sales distribution center, the Daily Economic News reporter has visited the mining machine business in Huaqiang North many times, from the first round of soaring market in 2017, to the mining machine winter in 2018, and then to the recovery at the end of 2020, the mining machine jianghu in Huaqiang North has experienced many ups and downs.
The Chia coin mentioned in the above statement is a very hot virtual coin recently. on the afternoon of May 19, the reporter visited the miners on the 1st to 4th floor of Sage Plaza and found that almost all mining stores had posted ads for Chia coin miners.
The reporter learned that Chia was incorporated in August 2017, claiming to develop an improved blockchain and smart trading platform. The founder of Chia is also the founder of Bit Torrent, the developer of the BT seed downloader that people in China are more familiar with.
On March 19 this year, Chia coin was officially launched on the main website and started trading on May 4. The starting point was on May 11 when, without advance notice, Amazon Cloud Services suddenly announced that it would invest about 1 billion yuan in the Chia ecology and launch the Chia coin cloud P-plate service. With all parties pushing, the coin price once surpassed $2,500.
Unlike Bitcoin and Ether, Chia uses Proof of Time and Space (PoSt), and the larger the capacity of the hard drive involved in mining, the greater the chance of getting tokens. As of now, the amount of hard drive space people are taking up to mine this coin has reached 6.34 EiB, the highest in the world and equivalent to 5% of the annual global hard drive production.
In front of a mining machine store, there are two sales people assembling the frame of Chia mining machine, they told the Daily Economic News that Chia mining machine is currently the hotter mining machine with the shortest payback cycle, which only takes 1~3 months. And compared with the one-year payback cycle of Bitcoin and Ether, Chia miners are more popular among miners.
Led by Chia coins, the price of hard drives has also gone up. According to CCTV, Sage Building merchants said, “Hard drive prices peaked around April 20, and 16TB hard drives that should have sold for around 3,000 yuan could sell for more than 6,000 yuan.”
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