CHINA ALERT! A 1,167ft Skyscraper Started SHAKING For No Reason

Added: 2026-06-02

[00:00:00]In the city of Shenzen, where the skyline is a stopwatch, Seg Plaza was once the proudest number on the dial.

[00:00:08]1,167 ft of pale concrete with a silver needle on its head. A tower the city used as its own self-portrait. And then on the afternoon of May 18th, 2021, on a Tuesday so unremarkable the wind never crossed 9 m/s, the self-portrait began to move. Coffee cups slid off desks 70 stories above the street. Thousands of people poured out of the lobby and looked up at a building that should not have been moving and was. Why? This is SEG Plaza, a 72story skyscraper built and named for the Shenzhen Electronics Group, a tower that was once the proud face of Chinese high-rise engineering.

[00:00:58]It was the world's tallest building using concrete filled steel tubular columns.

[00:01:04]It received the second prize of the National Science and Technology Progress Award in 2000.

[00:01:11]And then over 3 days in May 2021, it resonated 21 times.

[00:01:19]The cause was not an earthquake. It was not the subway running underneath it. It was not the construction next door. The cause was a decision made before a single floor was poured.

[00:01:33]A decision to build the tower faster than the rules of building allowed. This is the terrible engineering behind Shenzen's swaying skyscraper.

[00:01:44]To understand what went wrong inside SCG Plaza on May 18th, 2021, you have to understand a phrase that the city of Shenzen taught the rest of China to say with pride.

[00:01:57]Shenzhen speed.

[00:02:00]In 1982, 2 years after the Chinese government opened Shenzhen as its first special economic zone, the city's leaders proposed a 50story international trade center.

[00:02:12]They had almost no experience building skyscrapers.

[00:02:16]They built it anyway.

[00:02:18]By 1985, the Guamo building was finished. Local lore says it rose at a rate of one floor every 3 days.

[00:02:26]That pace was given a name, Shenzhen speed. It became a standard, a boast, a challenge to anyone who built afterward.

[00:02:37]For a decade, contractors across China tried to match it. But by the mid 1990s, Shenzen wanted to break it.

[00:02:46]In 1996, the Shenzen Electronics Group went public and rolled some of the proceeds into a flagship project. The SCG Plaza would be taller than the Guauo building.

[00:02:58]It would use a structural system that had never been attempted at this scale anywhere in the world. A forest of steel tubes filled with concrete.

[00:03:07]And most importantly, it would be built faster than anything the city had ever raised.

[00:03:15]According to a graduate student thesis unearthed by Chinese media in 2021 and reported by Bloomberg, SEG Plaza did not merely match Shenzen's speed. It beat it.

[00:03:29]The tower rose at a pace of one floor every 2.7 days. The same thesis also noted something colder. Construction had begun before the design and review process was even complete. Updated plans were delivered while concrete was already curing on the floors below.

[00:03:48]Completed sections sometimes had to be reworked because the drawings had moved on without them.

[00:03:54]The blueprints were chasing the building. The building was not waiting for the blueprints.

[00:04:00]This is the original sin end of SCG Plaza.

[00:04:04]Not a single weak bolt, not a corrupt inspector.

[00:04:10]The original sin is the decision that the schedule mattered more than the sequence. That a tower could be reviewed in midair instead of on paper.

[00:04:19]That speed was a virtue even when speed meant pouring concrete around plans that were still being drawn.

[00:04:26]Every consequence that followed, every panic, every viral video, every warning from a foreign consulate traces back to that single choice.

[00:04:39]For decades, engineers who design tall buildings have respected a quiet rule about decoration.

[00:04:46]Anything you put on top of a finished tower is not the tower. The flag poles, the lightning rods, the antennas, all of it is jewelry on a building. And jewelry behaves differently from architecture.

[00:05:00]Jewelry sings in the wind. SEG Plaza was crowned with two long masts.

[00:05:07]Roughly 64 meters of steel rose above the roof, lifting the official tip height of the tower from 957 ft to 1,167 ft.

[00:05:20]That extra 210 ft was what made SCG Plaza one of the tallest skyscrapers in China at the turn of the millennium.

[00:05:29]It was also what made it a 64 meter wind instrument.

[00:05:33]To understand what those mass did on May 18th, you have to picture a phenomenon called vortex induced resonance.

[00:05:42]When wind slides past a slender vertical object, it does not pass cleanly. It peels off the back in alternating swirls, one to the left, one to the right, in a regular rhythm. Engineers call this pattern a Carmen vortex street. Each swirl gives a small push.

[00:06:02]If the rhythm of the pushes lines up with the natural frequency of the object, the object begins to vibrate harder and harder at the same beat.

[00:06:13]The cheapest version of this phenomenon is the way a car radio antenna trembles at certain speeds on the highway.

[00:06:20]The most expensive version is a 1,167 ft tower in the middle of a city.

[00:06:27]By 2021, two decades of weather had aged the masts on top of SCG Plaza.

[00:06:34]Investigators later reported that their physical features had changed. Minor damage had accumulated. Their natural frequency had drifted. On the afternoon of May 18th, with wind reported at no more than 9 m/s and an 8° C temperature swing across the day, the rhythm of the vortices and the rhythm of the masts lined up. The needle on top of the tower began to oscillate in resonance.

[00:07:02]And because the masts were bolted into the roof, the building below began to oscillate with them. Imagine a knitting needle taped to the top of a flag pole.

[00:07:12]Tap the needle in just the right rhythm and the whole pole starts to whip.

[00:07:19]That is what happened in Haong Bay on a Tuesday lunchtime.

[00:07:23]The first sign came at 12:31 p.m. Office workers on the upper floors of SEG Plaza felt the desks shift. The light fixtures swayed. The structure groaned.

[00:07:37]Within minutes, thousands of people inside the tower and the giant electronics market in its podium were sprinting toward the exits.

[00:07:45]Cell phone footage from the street showed crowds streaming out of the lobby and racing across Shenan Boulevard, looking up over their shoulders at a tower that should not have been moving and was. By that evening, hashtags about the swaying building had drawn more than 780 million views on Waybo.

[00:08:05]Investigators arrived. The Shenzhen Emergency Management Bureau ruled out an earthquake almost immediately.

[00:08:14]The Shenzen Housing and Construction Bureau commissioned realtime monitoring of vibration frequency, tilt rate, and settlement.

[00:08:22]The structure, they said, remained within official safety parameters.

[00:08:27]The main building was not in danger of collapse. And yet, on May 19th, the tower swayed again. On May 20th, it swayed a third time.

[00:08:38]Monitoring data later showed 21 separate resonance events between May 18th and May 20th. The United States consulate in Guangha issued a notice telling American citizens to avoid the area, citing inadequate information to assess the safety risks. The building's owner sealed the tower on May 21st.

[00:09:00]Tenants who had been told the structure was sound were now told they could not enter at all.

[00:09:05]Merchants in the electronics market hauled their stock onto the sidewalk in 35° C heat. The investigation that should have ended in a week stretched into months.

[00:09:18]So why not just fix it?

[00:09:20]This is where the story of SEG Plaza becomes something more than an engineering problem.

[00:09:27]because the engineering solution exists.

[00:09:30]The engineering solution was identified by the official expert panel 2 months after the first sway. They concluded that the cause of the resonance was the masts on the roof and the remedy was to remove them. That is not a metaphor. On July 16, 2021, the building's management announced a 32-day program of work to dismantle the aging masts, repair the damage that had accumulated over 20 years, and redistribute the lightning rod and aviation marker on a smaller redesigned crown.

[00:10:05]Tenants were told to move their valuables out of the building. The skyscraper and the surrounding roads were cordoned off. And then floor by floor at the top, the part of SEG Plaza that had made it 1,167 ft tall was cut away. When the work was done, the building was still standing.

[00:10:27]It was also shorter.

[00:10:29]The official tip height of SEG Plaza dropped from 355.8 m to roughly 291.6 6 m.

[00:10:40]The 1,167 ft tower became a 957 ft tower. The number on the postcards, the number on the brochures, the number the city had once boasted about no longer existed.

[00:10:54]That is the cost of the original sin.

[00:10:58]The fix did not heal the building. The fix subtracted a piece of the building.

[00:11:03]A surgeon does not love an operation that ends an amputation. But sometimes the only way to keep a patient alive is to remove the part that is making them sick.

[00:11:14]The masts on the roof of SCG Plaza had become that part. The tower that the Shenzen Electronics Group had built to be the tallest concrete filled steel tube structure in the world ended up surviving by giving up the height that had been its identity.

[00:11:31]And the deeper problem did not leave with the masts.

[00:11:35]SCG Plaza was not an isolated mistake.

[00:11:38]It was a symptom of a city that had spent 40 years measuring its skyline against a stopwatch.

[00:11:46]For most of those 40 years, Shenzen contractors made cement with sea sand.

[00:11:51]Seaand is cheaper than river sand. It is also full of chloride, which corrods the steel inside reinforced concrete from the inside out.

[00:12:01]Many of the towers raised at Shenzen speed in the 1980s and 1990s contain that sand.

[00:12:08]The reckoning for those decisions is not a single panicked Tuesday in May. It is a slow tide of inspections, retrofits, and quiet demolitions that the city will pay for over decades.

[00:12:24]SCG Plaza was the loudest possible signal that this tide was coming in. It happened in broad daylight in front of 500,000 daily visitors to the busiest electronics market in Asia on a building that the city had used as its own self-portrait.

[00:12:42]Public confidence in Chinese high-rise construction did not recover quickly.

[00:12:48]The day after the first sway, Waybo users were already writing posts that read like an indictment of the entire skyline.

[00:12:56]in today's cities. One user wrote, "There is no guarantee of the quality of these skyscrapers."

[00:13:03]So, what was the terrible engineering behind SGE Plaza?

[00:13:08]It was not just an old antenna. It was not just a car vortex street. It was a flawed philosophy.

[00:13:17]It was the belief that you could pour concrete around an unfinished blueprint and trust the blueprint to catch up.

[00:13:24]The belief that one floor every 2.7 days was a triumph instead of a warning.

[00:13:30]The belief that decorating a tower with 64 m of steel needle on the roof was a cosmetic decision instead of a structural one. The belief that physics would politely make room for the schedule. SCG Plaza did not fall. It was never going to fall. The main structure, as the inspector said, was safe. But for three days in May 2021, the city of Shenzen watched the most famous tower in its electronics district shake in a wind that should not have moved it.

[00:14:04]And the only way to stop the shaking was to climb to the top of the building and cut off the part of it that had once made the postcard.

[00:14:12]Today, the tower stands shorter and quieter than the one the city remembers.

[00:14:17]Its podium fills again with merchants.

[00:14:20]Its observation deck is open. The crowds in Haang Bay walk past it without looking up. It is a 957 ft monument to a 1,167 ft ambition.

[00:14:33]A reminder written in concrete and steel above one of the busiest streets in China of the oldest rule in construction.

[00:14:42]Gravity does not negotiate and the cheapest schedule is never the cheapest schedule.