Building Integrity
Taipei 101 is renowned as an architectural and engineering marvel, owing to the innovative techniques implemented to ensure structural stability amidst challenging environmental conditions and potential disasters. The building's design factors in its vulnerability to earthquakes, exemplified by a 7.1 magnitude tremor experienced during construction, as well as its resilience against natural disasters, such as a category 5 typhoon in 2015. These incidents underscore the necessity for robust structural integrity and flexibility to withstand unforeseen calamities.
Taiwan Geographical and Tectonic Features of Taiwan
Why Taipei 101 we need special structural design?
Geographical Location
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Its location exposes it to the path of typhoons, which are powerful tropical cyclones that form over warm ocean waters in the Pacific.
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Taiwan's proximity to the Western Pacific Basin, where typhoons originate, means that it frequently experiences these intense storms during the typhoon season, which typically runs from May to October.
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The mountainous terrain of Taiwan further exacerbates the impact of typhoons.
Taiwan Typhoon Route Example (Source: OCHA, 2009)
The island's central mountain range runs north to south, dividing Taiwan into eastern and western regions. When typhoons make landfall, they often interact with these mountainous areas, causing orographic lifting, which enhances rainfall on the windward side of the mountains. This can lead to flash floods, landslides, and mudslides, particularly in vulnerable areas with poor drainage or deforestation. Taiwan's geographical location in the Western Pacific Ocean exposes it to the direct impacts of typhoons, making it imperative for the nation to implement robust mitigation measures to minimize the potential damage and protect building structures.
Tectonic Setting
Taiwan Major Faults(Huang et al., 2017) Taiwan Tectonic Setting(Source: Mikenorton, 2022)
​Taiwan's tectonic setting is characterized by its location at the convergence of several tectonic plates, making it a seismically active region. The island lies along the boundary of the Philippine Sea Plate to the east and the Eurasian Plate to the west, with the Philippine Sea Plate subducting beneath the Eurasian Plate along the eastern coast of Taiwan. This subduction zone is known as the Ryukyu Trench. The collision and subduction of these tectonic plates result in frequent seismic activity, including earthquakes and the occasional occurrence of tsunamis. The interaction between the Philippine Sea Plate and the Eurasian Plate has led to the formation of the Central Mountain Range, a prominent geological feature that runs along the length of Taiwan. In addition to subduction-related seismicity, Taiwan is also influenced by the presence of numerous active faults distributed across the island. These faults accommodate the ongoing tectonic movement and contribute to localized seismic hazards. Among the most well-known faults is the Chelungpu Fault, which caused significant damage during the 1999 Chi-Chi earthquake. Overall, Taiwan's tectonic setting is complex and dynamic, shaped by the convergence and interaction of multiple tectonic plates. This geological activity not only contributes to the island's rugged topography but also presents challenges in terms of seismic risk management and disaster preparedness.
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Reference: Taiwan History Seismic Data (Wu et al., 2008)
Three wind-related issues that engineer have to deal with
Reference: The Engineering Hub (2023)
01.
High Wind Speed
The open space at higher altitudes allows for higher wind speeds due to the fewer obstructions that could slow down the wind.
02.
Large contact area with wind (force)
Increase in the surface area of the building, which provides a larger platform for the wind to push against.
03.
Sway of the building
With the increase in height, structures become much more flexible and easier to sway by the wind forces.
Two peaks to be avoid
Reference: The Engineering Hub (2023)
01.
Earthquake
Due to the unique geographical location and tectonic features
02.
Damper
To see how damper aviod the disastrous impacts from earthquakes
So... How Engineer Deal with the two peaks?
01 Tuned Mass Damper’s Function during Earthquakes and Typhoons
Seismic waves generated by earthquakes can induce various types of movement in buildings, depending on factors such as ground motion frequency, direction, building height, and construction. This movement, ranging from swaying to oscillation, poses a risk of structural failure if excessive. Similarly, the force of wind against tall buildings can result in significant motion, even exceeding a meter. This motion, characterized by swaying or twisting, can affect upper floors and compromise the stability of skyscrapers. The tuned mass damper is a device mounted in structures to reduce mechanical vibrations. Its oscillation frequency is tuned to be similar to the resonant frequency of the building it is mounted to, and reduces the object's maximum amplitude during the earthquake or typhoon seasons.
Tuned Mass Damper_©99percentinvisible.org
Source: (TenTwenty | Webdesign, 2017)
Taipei 101 Mass Damper Location
At the top of Taipei 101, spanning from the 86th to the 92nd floors, resides a colossal pendulum known as a Tuned Mass Damper (TMD). This pendulum serves as a counterbalance to mitigate the effects of wind forces, thereby minimizing the building's sway during typhoons. Additionally, the presence of the damper enhances occupant comfort during periods of strong winds.
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Operating on the principle of utilizing building motion, the damper employs giant shock absorbers to convert motion into heat by directing fluid through small internal apertures. As the building sways, the mass within the damper moves in the opposite direction, effectively dissipating energy generated by wind oscillations and reducing overall movement.
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Comprising 726 tons and measuring 6 meters in diameter, the pendulum consists of stacked steel plates and accounts for 0.24% of the total building weight. Notably, during a recent Category 5 typhoon, the damper exhibited an unprecedented sway of 100 centimeters or 39 inches.
reference: (TenTwenty | Webdesign, 2017)
02 Structure and foundation
Explaination of how engineer enhance the building integrity
Foundation
Foundation Details_©youtube.com
The site of Taipei 101 necessitates a meticulously planned foundation system due to its soil composition, characterized by soft clay adjacent to colluvial soil with low load-bearing capacity. Additionally, a layer of soft sandstone lies beneath at a depth of 40 to 60 meters, requiring a sturdy foundation. The structure employs a matte foundation with bored piles to distribute superstructure loads. Its 21-meter-deep basement, coupled with a water table 2 meters below ground level, exerts an uplifting force on the foundation. Consequently, a 1.2-meter-thick, 47-meter-deep slurry wall was constructed to support below-grade excavation and foundation work.
Superstructure
Engineering
The building rises 508 meters above the ground and resembles an ancient pagoda. Its structural design draws inspiration from the appearance of bamboo, which is lightweight, flexible and strong
Building section and details_©civilengineeringforum.com
Ductile steel framework
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A ductile steel framework encases the supercolumns, designed to flex during earthquakes. These frames support the outward slope of the building, creating its distinctive inverted pyramid shape.
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Floor-high steel outrigger trusses
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These trusses connect the core columns to the supercolumns, widening the building to enhance resistance against overturning.
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Pliant steel
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The tower utilizes pliant steel with a low yield to ultimate tensile stress ratio, enabling it to accommodate plastic strain during natural disasters. This steel is weldable, with a microalloyed, thermomechanically processed, and accelerated cooled fine microstructure. Five types of steel plates, with yield strengths ranging from 412 to 510 MPa and tensile strengths from 570 to 720 MPa, were used, all with a carbon equivalent (Pcm) of less than 0.29. These plates were produced using the TMCP process, requiring specially constructed steel processing plants.
Learn more about the structural engineering of
Taipei 101
Other special characteristics related to building integrity
Security System
In short: 24/7 protection, 365 days a year. Professionally trained security personnel and an advanced integrated electronic security system utilize and manage the visitor pass system, access control management system, and elevator management to improve operation of the whole building security.
Fire System
The most complete fire protection system, including non-combustible building materials, is used in the main building and all renovation work. When an emergency occurs, the integrated safety programs are automatically activated, fire doors are closed, and smoke exhaust systems are activated. Escape routes are supplied with air and pressure. There are two refuge rooms in the mechanical floor on every eighth floor. The mechanical floors above the 34th floor have outdoor refuge platforms to ensure a safe and sound environment and have obtained gold fireproof seals.