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Vivian Au

As Super Typhoon Ragasa battered Hong Kong with hurricane-strength winds on Wednesday morning, some worried residents felt their high-rise buildings sway, but experts and authorities have assured the public that such movements are normal.
Ragasa, which triggered the highest-level No 10 warning signal, came within about 100km south of Hong Kong in the morning before the storm was downgraded to a severe typhoon in the afternoon.
“Most of the buildings in Hong Kong have been built with wind calculations in mind, and vibration is an expected phenomenon when they face strong winds,” Robin Leung Chi-tim, president of the Hong Kong Institute of Surveyors, said on Wednesday.
He said that the taller and slimmer a building was, the higher the chance it was expected to sway in strong winds.


Leung added that such buildings were designed with elasticity, which allowed them to sway and then return to their normal position.
Elasticity is a material’s ability to stretch, bend or change shape when a force is applied to it, and then return to its original shape and size once that force is removed.
Leung reassured the public that the swaying did not compromise safety, as a rigid, non-swaying building would be “overdesigned and not cost-effective”.

A resident who identified himself as Peter and lives in a high-floor flat in Tseung Kwan O said that he felt his building sway so much in the morning that even the light fixtures in his home were moving visibly.
He expressed serious concerns about building safety.
The Buildings Department said on Tuesday in a social media post that it was a “normal phenomenon” for residents in high-rises to feel some swaying.
The department said that the reinforced concrete used in most skyscrapers had ductility, which refers to how much a material can be stretched or pulled without breaking.
It added that common structural components like walls underwent slight deformation from external forces, which was usually not easily noticeable to the naked eye.




Tony Za Wai-gin, past chairman of the building division of the Hong Kong Institution of Engineers, said buildings were constructed with a “pendulum effect” in mind, which allowed them to sway when facing strong winds.
However, he insisted that the extent of the swaying should not be excessive, saying it should not exceed one five-hundredth of the building’s height.
Veteran structural engineer Ngai Hok-yan said that authorities had provided clear guidelines for building structures with elasticity to withstand strong winds and extreme weather.
“Buildings swaying within their elastic limits is normal,” he said.
He added that normally, when a building swayed, its structural integrity should remain safe.
The Observatory issued the No 8 typhoon signal at 2.20pm on Tuesday and upgraded the warning to No 9 and No 10 in the early hours of Wednesday.
Ragasa maintained a maximum wind speed of 220km/h near its centre on Tuesday, beating the 210km/h recorded for Super Typhoon Saola, which triggered a No 10 signal in 2023.
The China Meteorological Administration had dubbed Ragasa the “king of storms” of the northwestern Pacific Ocean, warning that it would be the strongest typhoon to hit the country this year and would bring extreme rainfall.


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Hong Kong

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Some worried residents felt their high-rise buildings sway as hurricane-force winds battered the city


Some worried residents felt their high-rise buildings sway as hurricane-force winds battered the city.


Hong Kong buildings swaying in Super Typhoon Ragasa ‘nothing to worry about’

.css-1c6uqr6{color:inherit;font-weight:inherit;font-size:inherit;font-family:inherit;line-height:inherit;overflow-wrap:break-word;}Some worried residents felt their high-rise buildings sway as hurricane-force winds battered the city

Some worried residents felt their high-rise buildings sway as hurricane-force winds battered the city