Structures, like people, have character. They could be warm and inviting, graceful, elegant, intimidating and overbearing, mysterious or delicate. Many elements shape a building’s character - from its design to the colours and the materials used in construction.
Metal as a construction material has had a long history of producing structures with striking personalities.
For over a century, the Eiffel tower, in France, which is made of Iron, has symbolised industriousness, and to some, it is a figure of love. It is daring and domineering as it dominates every photo captured of Paris’ skyline.
Steel, one of the most popular metals in construction, has also competitively produced innovative and equally outstanding monumental structures.
A few examples would be the Gateway Arch in the US which is simple in design yet richly symbolic, the Beijing National Stadium, also known as the bird’s nest, and the Sydney Harbour Bridge in Australia, among others.
Increasing production and innovation
Over the years, steel has become the go-to construction material for developers who want to produce unique structures. Subsequently, the steel industry has adapted to this demand by increasing production and advancing the steel making process.
The World Steel Association reports that in 1950 for instance, there was only 189 million tonnes of steel produced in the world, while 70 years later in 2020, that figure had risen tenfold to 1,878 million tonnes.
These numbers show that steel is gradually becoming an essential construction material after concrete. And the increase in production is definitely as a result of advanced production processes which improve the metal’s workability, malleability and durability.
“As a permanent material which can be recycled over and over again without losing its properties, steel is fundamental to a successful circular economy,” this statement by the World Steel Association captures one of the benefits of using steel in construction. Its recyclable nature makes it sustainable and to an extent environmentally friendly.
Steel can be produced from mined iron ore or by melting scrap metal and re-producing it into different pre-engineered building parts. In addition, steel products are pre-fabricated at the manufacturing process (as opposed to manual brick and mortar), therefore cutting construction time significantly.
Steel produced years ago was prone to rusting and corrosion. It was also too hard, and would break or buckle when exposed to excessive pressure. Under high temperatures, the metal would also weaken and expand, lowering the integrity of structures made from it. The production process, especially in the 90s, was also costly, therefore the world produced smaller quantities of the metal. The 21st century, however, came with advanced production capacity and better-quality steel.
Tinning, one of the final stages in the steel making process, involves coating metals to prevent corrosion. Advancements in the tinning process have resulted in better quality steel with lower maintenance cost. Annealing, another critical stage in steel production, entails heating the metal at a specified temperature and creating a suitable environment for the metal to cool at a strategic pace. Annealing is done to alter the properties of a metal and reduce impurities.
The resulting product is easier to cut and shape and is less hard. Advancements in the annealing process have impacted what professionals in the construction industry can or cannot do with steel. With improved production processes, architects, structural engineers and other players in the industry got creative with structural designs. This explains why we are seeing some of the interesting innovations in steel construction, from prefabricated steel buildings built to steel facade and Architecturally Exposed Structural Steel (AESS).
Architecturally Exposed Structural Steel (AESS) is one of most exciting innovations which combines aesthetics with functionality. Traditionally, steel has been used to reinforce concrete structures, meaning the metal is often hidden in layers of cement, concrete and brick. AESS however leaves the steel structure exposed as a way of showing off the detailing and the beauty of the metal. AESS is often used in high-end projects, resulting in sculptural structures such as the Beijing Museum.
In some cases, architects will combine AESS with glass to enhance its functionality and aesthetic purposes. AESS parts are normally pre-fabricated in factories, with manufacturers taking excessive precaution when handling the parts to ensure every detail is as specified in the design.
From crisp lines, smooth curves and fine geometric shapes, anything is possible with AESS, making steel one of the most versatile construction materials.
You can never achieve certain detailing in construction with concrete, wood or glass, which are less flexible when it comes to creating shapes. AESS brings art into construction and it redefines the experience of anyone who visits the building, be it a library, company headquarters, an airport or a monumental structure in memory of a public figure.
Pre-Engineered Steel Buildings
Pre-fabricated buildings are the grand 21st century innovation as they revolutionised our approach to construction. There is, however, a big difference between materials used in pre-fabricated structures. Wood, concrete and steel are some of the popular ones, and each offers a unique set of advantages. Pre-fabricated steel structures are popular due to their durability.
Steel can withstand different climatic conditions and routine use does not wear it out fast, unlike wood which may rot when exposed to water. With advanced production technology, prefabricated steel is galvanised to prevent rusting, a common concern when it comes to metals.
Prefabricated parts are manufactured in factories and assembled on site, a process that could take eight to 10 weeks. The light gauge steel used is naturally lighter, making the assembling process much easier.
One key advantage of using prefabricated steel is the fixed cost aspect. Unlike brick-and-mortar construction whereby the construction cost inflates during execution (depending on the contractor’s project management skills), buying a prefabricated building comes at a fixed cost.
And in the recent past, steel companies have come up with ways to produce aesthetically pleasing designs that blend in well with conventional buildings, from multi-story commercial buildings to sizeable bungalows. Steel prefabs are also versatile as they can be designed into churches, schools, warehouses, offices, residential buildings and factories.
Finally, cladding is another innovative way of using steel. Materials such as wood, stone, concrete, aluminium and copper have been used in cladding, with each offering diverse benefits. Stone brings an element of edginess and nature while copper is loved for its orange-brownish finish.
But if you want a toned down, chic, silver-like appearance on your exterior walls, steel is your metal. In addition to the muted, yet elegant look, steel is a strong and durable cladding material that can protect a building for ages at a low maintenance cost.
Galvanized steel withstands rainy and dry seasons, making it the perfect clad if you want to cut down on re-painting cost of a building.
These are but a few ways to use steel innovatively, but with advancing technology in production, there will be endless ways of constructing with steel.
For instance, as the need for renewable energy increases, wind turbines which are made of steel will be in high demand in the near future. Steel turbines are created with sharp blades which collect the kinetic energy in wind. The energy is then turned into electricity.
Kenya is host to the largest wind power project in Africa, The Lake Turkana Wind Project which was launched in 2019. It seems concrete, which has dominated the construction industry for centuries, just got a strong competitor.
