Posts tagged with "Skyscrapers":
Seattle is updating building codes for new skyscrapers after a shocking study revealed that the power and nature of earthquakes in the region pose a significant threat to its tall buildings, one that is worse than experts could have imagined.
The Seattle Times recently reported on results from the M9 Project, a four-year study that aimed to estimate the effects of a magnitude 9 Cascadia earthquake, revealed that the vast, sediment-filled basin under Seattle can magnify the type of ground shaking that puts high-rises at risk of collapse by a factor of two to five, which can trigger stronger surface effects than earthquakes in nearby California.
When rattled by an earthquake, the Times explained, the region's glacial-packed soils, which can extend more than four miles underground, violently shake and convulse, trapping massive seismic waves within the basin that underlies most of the city. Intense shaking like this could last for two minutes, which is four times longer than the average quake. While shorter buildings under 10 stories can withstand the earth's back-and-forth motion, tall buildings tend to whip back and forth under those conditions until they are on the verge of collapse.
As the Times reported, as a result of these findings, Seattle and its neighbor, Bellevue, plan on revising seismic construction standards for new buildings over 240 feet, or over 20 stories tall. These standards will require high-rises to be stronger and more sturdy than their predecessors, without the additional cost.
The plan to revise building codes has also raised concerns regarding Seattle’s older high-rises, many of which were constructed between the 1960s and 1990s, prior to when the dangers of earthquakes were fully understood. Older high-rises have a greater risk of major damage and collapse due to their fracture-prone welded joints, which are supposed to secure the steel frame, as well as their poorly-reinforced concrete supports. Seattle’s renowned Rainer Tower, for example, with its golf-tee-shaped base, was built in the 1970s and undoubtedly has fracture-prone welds. According to the study, buildings like that are up to five times more likely to collapse during an intense earthquake than a modern building.In Seattle, where the seismic threat to skyscrapers is higher than in California because of the city's sedimentary basin, there have still been no attempts to research and pinpoint dangerous high-rises. While the city is taking steps forward by enhancing construction standards, retrofitting old concrete and steel high-rises may be the next necessary step. This may prove costly, but taking time to fix the underlying structure of older buildings could prevent serious levels of damage that can be catastrophic to the community.
One hundred and thirty-three years after the first skyscraper appeared, in an era when air rights are just another tradable commodity and globalization can make one city feel much like another, Scott Johnson argues compellingly in Essays on the Tall Building and the City that skyscrapers have become a reflection of their particular region. To prove his point, the architect and cofounder of Los Angeles–based firm Johnson Fain closely analyzes high-rises in New York City, London, Paris, Tokyo, Shanghai, Abu Dhabi, and São Paulo through a series of essays and lush photographic spreads. In each essay, Johnson provides richly detailed context about the particular city’s history and its approach toward urban planning. His selection of cities is not accidental; from one of the newest metropolises to some of the oldest, Johnson demonstrates how each region’s tall buildings are shaped by a particular history and culture.
In his chapter on Paris, Johnson delves into the city’s ruthless zoning practices, from the 1850s push to transform medieval alleyways and pedestrian haunts into grand, easily patrolled boulevards, to the 20th-century creation of perimeter “new towns” that encouraged growth only on the outskirts of the central city. Famously, the city banned all high-rises in 1972 after the public outcry over the Tour Maine-Montparnasse. As a result, many of Paris’s built skyscrapers bear a kind of hushed, almost reticent form, utilizing step-backs and semi-transparent facade elements to visually reduce their volumes. The four towers of the National Library of France use a combination of glass and wood shutters to create a vivid interior life but the appearance of a “monolithic nature” on the outside, for example.
In contrast, Abu Dhabi’s towers are rooted in a much more eager, demonstrative soil. The city’s relative lack of historical precedent gives rise to some of the most imaginative and fluid skyscrapers in the book; from the Capital Gate to the Strata Tower, Abu Dhabi’s skyscrapers reflect a big-picture idea of what a “global city” should be, their often mixed-use programs perched on a context-free coastline. Similarly, the frequently playful skyscrapers in Tokyo spring from a weird mix of strict building-code safety regulations and a kind of spot-zoning mentality stemming from a weak master urban plan. From the decorous facade of the Yamaha Ginza building to Jun Mitsui’s Ice Cubes, Tokyo’s signature skyscrapers are identifiable by a vivid energy pushing against strictures, like otherwise well-behaved children attempting to burst free from parental oversight.
Although an argument could be made that skyscrapers are inherently a global typology instead of a regional one due to the myriad financial, design, and political entities that help put them together, Johnson’s case studies offer a compelling aesthetic sampling. There are, of course, numerous nondescript towers that fill out every city’s skyline. In this book, Johnson concentrates on those buildings that share the characteristics he believes defines each metropolis; the wide variety of architectural firms, clients, and timelines involved elevates his observations beyond mere coincidence. Once you entertain Johnson’s thesis, it becomes easier to conceive of those towers that lack regional characteristics as merely structural tourists jostling among the denizens.
In keeping with the other two volumes of his series on skyscrapers, Performative Skyscraper: Tall Building Design Now and Tall Building: Imagining the Skyscraper, Johnson has attempted to create a book that is not only accessible to young architects but eye-opening to veterans of the profession. By virtue of sharing his nuanced eye and macroscopic understanding of each of these urban centers, Johnson provides not only a refreshing take on tall buildings, but also the idiosyncratic ground from which these cities spring.
“Essays on the Tall Building and the City” Scott Johnson, Balcony Press $45.00
Just like sea sickness, our propensity to motion-induced discomfort is situation and environment dependent. For example, people at a concert in a grandstand will accept a completely different level of vibration than those in a hospital operating theatre.The new simulation facilities will be funded by the Universities of Bath and Exeter, as well as the Engineering and Physical Sciences Research Council. The study hopes to shed some light on this curious phenomenon, and could possibly establish new standards for allowable levels of a building’s motion for the health and safety of its occupants. News via: Council on Tall Buildings and Urban Habitat (CTBUH). Written by Osman Bari. Want more from ArchDaily? Like their Facebook page here.