While high-rise buildings have long been a part of the urban landscape for some cities (first emerging in the late-19th century), others are just beginning to grow upwards. Commercial and residential uses tend to dominate high-rise developments, with commercial buildings accounting for 52% of such projects completed in 2016. With intensifying urbanization and a growing population, the opportunity to reduce a building’s footprint is often worth taking.
There are a number of factors contributing to the rise in building heights, with some of the key drivers discussed below:
As urban centers continue to grow and sprawl, the acute shortage of space is leading developers to build upwards. High density solutions are necessary to combat both the lack of space, and the cost of land, providing a high proportion of rentable floor space per unit area of land. The cost of land creates an effect that raises the per floor cost of a building of a given height and creates an incentive to build taller, in order to spread the land cost over a larger number of floors.
The suitability of a site will depend on site specifics, and the proposed use of the site. High utilization of a small site combats the cost of land.
In major cities that find themselves adjacent to agricultural land, there will be a restriction on random expansion and urban sprawl. Therefore, as the expansion of the city hits this boundary as it grows outwards, the only option will be to go upwards instead. There are also many other factors – for example, in Rio de Janeiro and Hong Kong, the quality of the terrain is a significant consideration, while the lack of suitable land area in locations like the United Arab Emirates can also cause issues.
The ‘going higher’ phenomenon is undeniably driving a significant proportion of the high-rise market. This is particularly true in the Middle East and Asia, with seven of the world’s ten tallest buildings in these locations. Of the high-rise buildings completed in 2016, a staggering 84% were in Asia, where it is often seen as an expression of progress and civilization.
Large uninterrupted elevations offer significant opportunities for economies of scale (as well as efficiency and speed). Modularization, rationalization of unit types and the standardization of section sizes, details and fixings all contribute in this regard. Furthermore, it is much easier for governments and local authorities to manage and plan for population growth within a smaller geographic area, which will result from high-rise construction. Ultimately, it is typically more economically viable to fulfil demand on public services and infrastructure.
High density solutions are necessary to combat both the lack of space, and the cost of land, providing a high proportion of rentable floor space per unit area of land.
Although high-rise buildings offer distinct benefits, it should also be noted that they can pose unique logistical issues, which can be reflected in the preliminary costs. Height, shape and size of such buildings, as well as the architectural treatment and articulation of the elevations all have an impact. Furthermore, incremental increases in height lead to disproportionate increases both in the overall mass and the resulting additional cost of main structural elements. Ultimately, the per square meter value of the completed project must be viable.
With high investment costs, long gestation periods and the potential for a high degree of repetition, the application of BIM technology can offer considerable benefits in the construction of high-rise buildings. From design optimization and plan installation to de-risking project investment, BIM can provide a degree of predictability that enables effective and efficient decisions to be made. The enhanced graphical techniques can bring about greater opportunities in the planning and communication of construction intent. It can be used to virtually induct teams onto the site and plan activities extensively, which in turn can offer improved productivity and safety.
The challenges posed by the design and execution of high-rise construction are considered some of the more complex issues within the industry, and are fundamentally down to a fine balancing act between engineering, economics and construction management. Buildings must not only be functional and economically viable, but they must be robust against wind loading and other elements, as well as accessible and fire safe. With the number of fires in high-rise buildings in recent years, the issue of fire safety is all the more fundamental in the construction of these developments.
Ultimately, high-rise developments form an integral part of the ecosystem of most major cities globally. Cityscapes are defined and punctuated by these tall buildings, which offer distinct benefits to the city and its population.