How steel helps Taiwan's tallest building, Taipei 101, survive earthquakes and other extreme weather events

Taipei 101, Taiwan's tallest skyscraper
Steel is used in multiple ways to ensure Taipei 101 is able to survive extreme weather events iStock

A combination of a structural system equipped with steel outrigger trusses and a central braced core, eight concrete-filled steel box mega columns, composite floors with reduced section steel beams and a steel sphere tuned mass damper helped Taipei 101, survive Taiwan’s fiercest earthquake in 25 years.

Located on what’s known as ‘the ring of fire’, seismic faults that encircle the Pacific Ocean, Taiwan is particularly susceptible to earthquakes and typhoons.  Consequently, all construction on the island must be designed with earthquakes and extreme weather in mind. So, when local architecture firm C.Y. Lee & Partners was working on the plans for Taipei 101, which at the time of launch, in 2004, was the world’s tallest skyscraper, the focus was on ensuring it could endure extreme weather conditions, including gusts of wind up to 60 miles per second, and earthquakes.

And, when Taiwan was struck by its most powerful earthquake in 25 years in April 2024, registering a magnitude of 7.4, the building was seen to visibly sway, as it was expected to do in the event of a tremor, but it experienced no structural damage. Two elements of its design, both featuring steel, are to thank for this.

The steel orb that helps Taipei 101 survive earthquakes
The steel pendulum within Taipei 101 serves as a tuned mass damper, which can reduce up to 40% of the building's movement iStock

Taipei 101 holds the world record for the largest tuned mass damper

Firstly, Taipei 101 retains its place in the Guinness Book of Records for having the world’s largest tuned mass damper or harmonic absorber, as they are also known. Tuned mass dampers are designed to move in an opposing direction to the oscillations of the structure within which they sit. Every tuned mass damper must be custom designed for the infrastructure it is to become a part of.

The turned mass damper in Taipei 101 was designed by Motioneering and constructed by A+H Custom.  The pendulum’s 730-ton steel sphere is suspended from cables anchored on the 92nd floor and stabilised by hydraulic cylinders. This particular tuned mass damper is especially vast to take into account the building’s height and its tendency to sway in an extreme weather event. As the steel sphere swings, it counteracts any swaying motion in the building’s structure and can reduce up to 40% of its movement. Visitors can now enjoy the views from the tower’s observation points and admire the orb that swings within it.

Secondly, Taipei 101 is constructed with steel-concrete composite elements, which are employed throughout the structure, extending from its deep foundations, outrigger trusses and mega columns to the composite floors that make up the tower.

When the compressive strength of concrete is combined with the tensile strength of steel, you create a structure that is simultaneously stable and elastic. In this case, it allows the building the flexibility to sway in extreme weather and the strength and rigidity to resist the forces that extreme weather events bring.

As climate change is leading to more extreme weather events and the risk of earthquake-related damage is high, architects and structural engineers are increasingly looking for the latest innovations in steel construction to make their designs safe and strong.