Super Typhoon Mangkhut, which lashed Hong Kong, Macau and southern China’s Guangdong province over the past weekend, also put the region’s many high-rises and supertalls to the test.

Iconic Hong Kong landmarks such as the 118-story International Commerce Centre, the 88-story International Finance Centre, the geometric, prism-like Bank of China Tower and others were largely unscathed on Sunday as Mangkhut swept through the city. The Hong Kong Observatory hosted the No 10 typhoon warning, the most severe level of its five-grade storm-warning hierarchy, for 10 hours.

Yet across the border in mainland China’s bourgeoning tech hub of Shenzhen, howling gales and squalls from the monster typhoon wreaked havoc.

Other than shattered windows, flooding and fallen trees that were everywhere to be seen across the region, perhaps the most dramatic and even slightly horrifying sight was the falling glass and debris from a swaying skyscraper.

Video clips of Shenzhen’s Ping An Finance Center – a 600-meter, 115-story office tower that is the world’s fourth-tallest building – being enveloped by rain and clouds with what appeared to be shards and debris falling from the humongous tower have gone viral on China’s social networking platform since Sunday.

Some said the tower, taller than the One World Trade Center in New York, was shaking as seen from the ground. Shenzhen recorded a top mean wind speed of 52.6 meters per second during the thick of the typhoon.

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The 600-meter, 115-story Ping An Finance Center in Shenzhen is currently the world’s fourth-tallest building. Photos: Asia Times

What has further fueled concern and online chatter about the safety of the supertall tower was a likely leaked e-mail communication between senior executives of the owner of the tower, the Shenzhen-based insurance conglomerate Ping An Group.

The e-mail, titled “safety precautions against Mangkhut,” was a reply to the group’s founder and chief executive officer Peter Ma, and it contained only one line in an enlarged font, stating that the tower “reached its designed maximum swing allowance of 2 meters just now.”

Photo: Weibo
A screenshot of the leaked e-mail, which noted the tower swung as much as 2 meters amid the strong gales. Photo: Weibo

Ping An Group issued a statement on Monday that after thorough inspection of the entire building, technicians found no substantial damage to its facade and glass walls and that its maximum pendulum movement recorded during the typhoon was around “50% of the designed range of its tuned mass damper,” without elaborating further.

The damper referred to is a device made of huge concrete blocks or steel plates mounted on higher floors of a skyscraper to absorb and reduce the amplitude of mechanical vibrations resulting from strong winds, so as to avoid discomfort and even outright structural failure.

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A diagram of a damper inside Taipei 101, the tallest building in Taiwan. Photo: Handout

Shenzhen’s construction and buildings authority also affirmed that the tower was structurally sound.

A structural engineer said the 2-meter horizontal swing was “minuscule” and unlikely to pose a threat to the tower’s structural integrity, compared with its height of 600 meters as well as its stout concrete and steel footing on the ground.

The tower once made headlines in March 2013, when its construction was halted by watchdogs because of the suspected use of adulterated concrete made with unprocessed sea sand, which could corrode the weight-bearing steel core over time. Construction resumed after satisfactory sample testings.

According to the tower’s structural designer, New York-based Thornton  Tomasetti, the 620,000-ton, 500,000-square-meter tower has eight main columns with trusses branching out to support each floor.