Skyscrapers have been long part of urban cityscapes. They are typically found in busy and dense urban areas and are considered especially convenient for commercial and business areas.Today, skyscrapers are an increasingly common sight where land is expensive, as in the centers of big cities, because they provide such a high ratio of rentable floor space per unit area of land.
History of High Rise
With our growing technological pace it is hard to imagine that the first skyscrapers were built in the 1880s! Although high rise apartments of over 10 stories have been found in Ancient Roman civilisations. The structural definition of the word skyscraper was refined later by architectural historians, based on engineering developments of the 1880s that had enabled construction of tall multi-story buildings. This definition was based on the steel skeleton as opposed to constructions of load-bearing masonry.The American technological revolution of 1880 to 1890 saw a burst of creativity in architecture and civil structure technology. It produced a wave of new inventions that helped architects to build higher than ever before: Bessemer steel, formed into I-sections in the new rolling mills which enabled taller and more flexible frame design than the cast iron of the previous era; the newly-patented sprinkler head allowed buildings to escape the strict, 23-metre height limit, which was imposed to control the risk of fire; and the patenting of AC electricity allowed elevators to be electrically powered and rise to ten or more stories.
Need for High Rise
As urbanisation becomes a key aspect of modern living, the need for space is essential. Cities find it far more convenient to build vertically than to spread horizontally. This is a key factor in managing city infrastructure and makes it easier for the governing bodies to manage the demands of a growing population.The design and construction of skyscrapers involves creating safe, habitable spaces in very tall buildings. The buildings must support their weight, resist wind and earthquakes, and protect occupants from fire. Yet they must also be conveniently accessible, even on the upper floors, and provide utilities and a comfortable climate for the occupants. The problems posed in skyscraper design are considered among the most complex encountered given the balances required between economics, engineering, and construction management.
Sustainability
In recent years the term Sustainability has turned from a trend to a necessity. Sustainability in the context of high rise buildings includes the built and natural environments, including the performance of structures, types of materials, construction practices, absolute minimal use of materials and natural resources, energy within the structure, and a holistically integrated building systems approach.Sustainability covers economic benefit, resource efficiency, environmental protection and social development. Well developed building codes are now geared towards sustainability. It is common practice for local and central government to build committees to provide sustainability and environmental codes. These codes must keep in mind both sustenance and business in mind. The LEED certification is an internationally recognised green building standard that has found great acceptance around the globe.
"1 Bligh Street" in Sydney is a pioneer in sustainable construction in Australia. It has been constructed as an ecologically sustainable development and was awarded six-star green status by the Green Building Council of Australia. Sustainable features include a basement sewage plant that recycles 90 percent of the building waste water, solar panels on the roof and air conditioning by chilled beams. It’s full double-skin façade with external louvres. These conserve energy, eliminate sky glare and optimise user comfort. The angle of the louvre blades is automatically adjusted according to their orientation to the sun. A naturally ventilated, full height atrium, on the southern side of the building, maximises natural light to each office level.Sustainability also includes the proper planning and operations of the building. The Hearst Tower, completed in 2006 is a great testament to this. The tower’s impact on the local and global tall building industry is evident, especially its forward-looking green strategies. Using 26% less energy than a building constructed to normal code, Hearst Tower features a distinct, thermal efficient diagrid that provides a vast open interior. Since completion the building has continued to receive a number of environmental upgrades, allowing it to keep pace with the latest green standards.
Touching on the building owner’s commitment to sustainability, Louis Nowikas, vice president of the Hearst Corporation, stated, "It is not enough to build a green building, we must make sure that the building continues to perform and improve over the long haul."
Technological Advances
Project teams and other experts are working tirelessly to improve high rise technologies.These interventions range from using more cost effective materials, improved supply chains and project and construction management methodologies, improving occupant comfort and research to improve aerodynamic damping and reducing seismic effects.
Some examples include, Hi-Res CFD Studies for Pedestrian Comfort, to provide an accurate analysis of the wind microclimate at the human scale around tall buildings.
The Brunkeberg System that allows for the rapid installation of façade units through a workflow incorporating special delivery containers, automated horizontal / vertical distribution, and crane-less lifting mechanisms with speeds of 60 m/s.
Image Source: awards.ctbuh.org
Habitats Rather Than Standalone
The impact of a tall building is far wider than just the building itself, and makes significant contributions to the urban realm in connection with tall buildings.Architects and planners ensure that new projects demonstrate a positive contribution to the surrounding environment, add to the social sustainability of both their immediate and wider settings, and represent design influenced by context, both environmentally and culturally.
Image Source: awards.ctbuh.org
Barangaroo South is Sydney’s largest urban renewal project since the 2000 Olympics and is targeted to become Australia’s first large scale carbon neutral community.Barangaroo is one of only 17 projects globally to be part of the C40 Cities-Clinton Climate Initiative’s Climate Positive Development Program. The site is capable of being water positive, with an on-site blackwater treatment plant capable of supplying one million litres of recycled water a day to the precinct and surrounding suburbs.
Barangaroo is also targeting zero net waste to landfill by 2020.
Upon completion Barangaroo South will become home to around 1,500 residents, there will be next generation office space for 23,000 workers, more than 80 new retail outlets and over 50% of the precinct will be open public spaces for everyone to enjoy.
Incorporating Design with Innovation and Sustainability
Shanghai Tower, pioneers a new prototype for tall buildings. Placed in close proximity to Jin Mao Tower and Shanghai World Financial Center, the tower rises high above the skyline, and has a curved façade and spiraling form symbolizing the dynamic emergence of modern China. But its twisting form goes beyond a whimsical design decision; wind tunnel tests confirm a 24 percent savings in structural wind loading when compared to a rectangular building of the same height. The tower’s program is organized into nine vertical zones. Each of these vertical neighborhoods rise from a sky lobby, a light-filled garden atrium that creates a sense of community and supports daily life with a varied program catering to tenants and visitors."Shanghai Tower shows the greatest commitment to communal space in a tall building since Commerzbank Tower completed in 1997. It contains the world’s first truly ‘inhabitable’ double-skin façade on a skyscraper, which is not only remarkable for its intended greenery, but its incorporation into the tower’s overall ventilation strategy. The sacrifice of valuable floor area to realize this social amenity proves that the aspirations for Shanghai Tower went far beyond mere commercial gain."
Antony Wood, Juror, Executive Director, CTBUH, Chicago
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