A new report shows North America has been surpassed by both Asia and the Middle East in terms of ‘supertall’ buildings (i.e. greater than 300 m [984 ft]), and that more than half of the planet’s highest-rising buildings have been built in last four years.
Engineering insurer Allianz Global Corporate & Specialty’s (AGCS’) paper, “Supertall Buildings Risk Bulletin,” examines the ever-accelerating growth of new-generation skyscrapers.
By 2020, the average total height of the tallest 20 buildings in the world is expected to be close to 600 m (2000 ft)—double the height of the Eiffel Tower—thanks to new technologies, materials, and design elements.
North America now accounts for only 16 percent of the world’s tallest buildings, and its highest—the 540-m (1776-ft) One World Trade Center in New York—is believed to be just taller than half the proposed Kingdom Tower in Jeddah, Saudi Arabia.
South East Asia (48 percent) and the Middle East (30 percent) are home to more than three-quarters of the tallest 100 buildings. China has 30 of the world’s top 100 tallest buildings in 15 cities, while Dubai is home to 20 percent of the tallest 50 buildings.
“The eastward trend is set to stay, driven by rapid economic and demographic growth, urbanization, strong investor appetite for flagship real estate assets, and lower labor costs than in the traditional Western markets,“ explained Ahmet Batmaz, AGCS global head of engineering risk consulting.
The report also looks at challenges with supertall buildings, as the world’s first mile-high towers are approaching. Elevator technology is lagging behind, with cars capable of ‘only’ transporting people about (2000 ft) due to braking and cabling limitations. Other challenges include:
? availability of materials to potentially replace steel and cement;
? safety measures for occupants and surrounding areas;
? damping systems to reduce negative impact from wind or seismic activity;
? solar heat gain with glass façades;
? cranage and lifting items to extreme heights;
? maintaining verticality as the building height increases;
? elastic shortening of constructed building elements as the imposed weight from the completed building increases; and
? fire risk both during construction and occupied phases.