From adding more height to a high-rise building to taking away ongoing costs through sustainability – steel structures always come out on top:
Whether it’s reduced construction cost or increased building height, there are numerous ways that steel structures get the ‘one-up’ on their construction counterpart, concrete.
Steel’s versatility offers contractors a number of commercial advantages, from design flexibility and reducing overall time spent on a build to its ability to be reworked or 100% recycled at a building’s end-of-life. These are just some of the reasons it is chosen over and above, or at least alongside, concrete as the main material of construction for a new building.
Steel is more cost effective than concrete, particularly for high-rise buildings, for a number of reasons.
Because a steel frame’s elements are pre-fabricated, pre-punched or even part-built in a factory, the build time, materials and labour required on site is reduced. Additionally, the manufacture of frames in approved factories ensures high quality control for a better end-product. The reduced time spent on site makes pre-made steel structures particularly attractive for developments in already populated areas; such as city centres where new office blocks are needed but disruption to neighbours is required to be kept to a minimum.
In Greater Manchester we supported the development of a multi-storey, multi-use facility, Vision Tameside, to benefit both current and future generations. Contractors working on behalf of the local authority were keen to use steel in the construction to allow for future reconfiguration of the two buildings, employing our expertise to develop a column layout for the steel frame, that can be adapted at a later date if need be.
The variety in steel frames available for use, from braced or moment-resistant frames to higher grade steel sections for more strength, grants designers’ flexibility to deliver both structurally sound and aesthetically-appealing buildings. Vision Tameside was praised for incorporating a striking, cantilevered façade as well as its internal adaptability.
As well as allowing for pre-fabrication before erection, steel’s high strength to weight ratio allows for reduced loads on the building’s foundations, so additional work to reinforce pre-existing foundations is not needed for steel structures. And, once erected, a steel structure is not delayed by slow strength gain, as concrete is, making the overall project more time efficient.
For these reasons, main contractors are more and more often changing plans from concrete constructions to steel, to enjoy costs savings without compromising on build quality. Our work with BAM Construction on a London office block in Kings Cross, is an example of this. Careful consideration had to go into the foundational structure and weight of the building – which we supplied steelwork, pre-cast stairs and metal decking for – as it stands over two Thameslink tunnels. Original plans for a concrete structure were revised to steel frames due to both weight and cost implications.
These benefits are being enjoyed by other contractors in the capital too – the Newfoundland development in London’s Canary Wharf towers from a small space, also straddling underground tunnels. Its builders used structural steelwork to make optimal use of a modest plot and the on-site restrictions placed on contractors during its build. Its small footprint (just 58m by 26m) meant a steel structure was the natural choice to ensure a lightweight but high-rise construction.
And these are just two of many examples. In 2019, 60 new high-rise buildings (more than 20 storeys) were completed in London alone. In such densely populated areas, constructions of so many tall buildings simply wouldn’t be possible without the time and social benefits steel structures ensure.
However, since the completion of these buildings, the world looks very different; particularly once-busy metropolitan areas. The construction and architecture industries are alive to the reality that the way we use our spaces and buildings could soon be very different, with the potential for mass ‘deurbanisation’ as more people work from home.
Luckily, steel, once again, steps to the fore to be part of the solution should the need arise to rethink usage of major cities’, like London’s, office blocks. Its adaptability, able to re-worked after construction, as well as during, means owners and managers of steel constructed buildings will be able to adapt their properties to meet changing demands.
The Newfoundland tower, mentioned above, demonstrates this. It is a build-to-rent space, chosen as best use of that plot – over hotel schemes and residential properties for sale – to meet the changing needs of London’s housing market.
However, that particular structure does also utilise concrete. In fact, it is a good example of how steel can be used in conjunction with concrete; steel’s construction material competitor is as often its partner as its counterpart.
As displayed by iconic buildings like Dubai’s Burj Khalifa or Kuala Lumpur’s Petronas Towers, which both use reinforced concrete for their main structures, combination of the two can be world-leading. But there will be few projects seeking quite the same grandeur as these – nor with the same seemingly endless budgets. And it is steel alone, thanks to its relative lightness, that allows for the uppermost floors of Burj Khalifa that make it the world’s tallest building.
High-rise buildings built with steel are able to accommodate more floors within the total height thanks to steel’s lightness and efficiency in not requiring as much depth as concrete to support the weight loading of additional floors.
And steels flexibility isn’t just in the multitude of structural forms it can take. Steel’s literal flexibility allows buildings to move with and deflect weather conditions like wind, so high rise buildings made with steel frames are better able to cope with adverse weather conditions; as Burj Khalifa, which withstands soaring temperatures and sandstorms, demonstrates.
These skyscraper’s locations in areas with little to no seismic activity, mean use of concrete in their structures is low risk. Were they in areas of high earthquake loading, such as the East Coast of the US or Japan, steel would be the preferred material, for its ability to withstand seismic loading. New Zealand has shifted from concrete to steel in its builds since a series of earthquakes in 2010 and 2011 in which a number of buildings were badly damaged and, tragically, hundreds of people were killed. Steel’s ductility allows it to withstand these types of shocks. Protecting inhabitants is, after all, the most important focus and benefit of a good building.
Steel is the ideal material for multi-story or high-rise buildings, granting commercial, social and physical benefits.