The high-rise future is here now
Updated: 2011-12-30 07:40
By Shi Jianguang (China Daily)
Building of the 606-meter-high Wuhan Greenland Center, in the business district of Wuchang in Wuhan, Hubei province, started just over a year ago, and when it is finished it will be China's second-tallest building. The project's total construction area is about 3 million square meters and the cost is 30 billion yuan ($4.7 billion, 3.6 billion euros). The complex will include five-star hotels, A-grade office buildings, luxury apartments and shops.
From the outside Wuhan Greenland Center is cone shaped. The building rises from a triangular base, tapering upward, thereby reducing the pressure of the wind and eddy currents, a perfect combination of high-rise design and practical structure.
Modern high-rise buildings originated in the US, and they quickly became a worldwide phenomenon. The Council on Tall Buildings and Urban Habitat (CTBUH) says that 10 years ago there were 286 buildings in the world over 200 meters tall; now there are 634. They are located in 32 countries and regions; 403 are in Asia, 63 percent of the total. Bahrain, Dubai, Indonesia, Kuwait, Qatar and Vietnam are particularly active in constructing such buildings. But the busiest market is China. The average height (421 m) of China's top 10 tallest buildings is much higher than that of any other country.
At present China accounts for about a third of the world's 634 high-rise buildings over 200 meters high; the US accounts for about a quarter, and India for just 0.3 percent.
The number of completed high-rises exceeding 200 meters and 300 meters has been a record every year since 2007. A total of 78 to 94 skyscrapers over 200 meters will have been completed this year, which will make 2011 a record breaker.
The development of high-rise buildings has undergone many changes over the years. CTBUH says that in 1990, 80 percent of the world's 100 tallest were located in North America. But by September this year that figure had dropped to 27 percent. High-rise buildings are mostly located in Asia (45 percent; China accounted for 34 percent), and the Middle East (24 percent).
Over the past few decades high-rise buildings have been used mainly for offices, but there has been a dramatic shift. Residential and mixed use in the past decade has increased from 12 percent to 38 percent.
In the past 10 years the structural materials used in these buildings have also undergone major change. The use of steel, which has been replaced by hybrid materials and concrete, has fallen from 90 percent in 1970 to about 23 percent.
With the height and the size of high-rise buildings on the increase, high-rise construction consumes a lot of building materials, so practicality of structure has become increasingly important. From these high-rise buildings, especially mega high-rise ones, we can see that design ideas often draw on cultural concepts, plant morphology, different physical life forms, practical use of mechanical forces, energy saving technology or sustainable development demands. Behind various structures and morphology lie these design aspects.
Architectural plans based on cultural concepts, national identity, history and other elements are a universal given. The resulting structural stability, uniformity, symmetry, and compliance with other basic principles are the basis for a practical structure. If you can draw on the cultural concepts in accordance with how a high-rise structural system is organized, and form an overall plan, the favorable conditions will be there for a practical structural design.
Various plant forms have natural growth characteristics. Imitating or drawing on their form elements to conceive an architectural idea gives birth to the natural growth factor in the formation of a rational structure; it is an appropriate way of conceiving high-rise building plans that will give birth to a practical structure. Mountains, churches, sails, shells, books, screws and other everyday items have to adapt to natural conditions or to meet the practical effects of wind and other natural forces. When such things are kept in mind, high-rise buildings will be highly practical in their structure.
Analyzing factors such as wind and earthquakes, which affect the level of high-rise building load, is one way of calculating practicality and layout in high-rise building plans. It is also a way of using scientific principles to guide engineering design. Integrating the features of the construction spot and the environmental conditions with practical mechanical force to form new and unique architectural design solutions is where the wisdom of the architect lies.
In light of the call for sustainable development, the way high-rise buildings achieve energy saving, environmental protection, green, low carbon and other design goals has become the focus of development. In planning, various technical goals and practical structural forms need to be combined Network-tube structures, floor rotation, separated traffic layouts and green space are just a few examples of where technical innovation can be applied. Analysis of high-rise buildings has shown that as long as you pay attention to the practical side of the structure, all kinds of ideas are feasible.
The world's accelerating urbanization has brought about a surge in the population density of cities. Urban expansion and all kinds of civil construction have sustained rapid development. With the resource constraints that the world faces, and the need to respect the environment, high-rise buildings have an unprecedented opportunity for development.
Respecting the needs of sustainable development, energy efficiency, disaster prevention and mitigation and improving the quality of life, those who design and build high-rise buildings face new challenges.
More emphasis needs to be put on the overall layout. Architectural plans and design can no longer treat elements such as furniture, fittings, interior space and partitioning, equipment, systems, structural systems, maintenance of external decoration, space environment as individual items. More attention needs to be paid to the unity of the function of each element and the overall needs.
For example, external maintenance and dcor can be solved by an integrated system of structure and equipment and of site environment. Resolving questions of internal space, functions such as transport, the environment and communication need to be considered as a whole. Revising the traditional division of labor and design philosophy holds the key to success.
High-rise buildings should reflect the flexibility and variability of the architecture. Paying more attention to the structural system as a whole not only satisfies structural needs but also respects architectural prerequisites.
In today's high-rise buildings another requirement is the latest technology relating to wind, solar and other renewable energy methods. Waste recycling and reuse, wastewater reuse and rainwater harvesting technologies have a bright future in high-rise buildings. Maximizing the use of these new technologies is essential if sustainable development is to be respected.
The way ahead involves exploring new structures, innovative design concepts and using high technology.
The author is a professor at Xiamen University.