What is steel?
Steel is an alloy of iron and carbon containing less than 2% carbon and 1% manganese and small amounts of silicon, phosphorus, sulphur and oxygen.
It is the world’s most important engineering and construction material. It is used in every aspect of our lives; in Building and construction products, Furniture, Motor vehicle body parts, refrigerators and washing machines, Cargo ships, Agriculture , Health Sector machinery etc.
Steel is categorized based on various different factors that can influence its properties and uses. For instance, the rate steel is cooled can impact how its molecules are joined together, as can the amount of time the steel is held at several critical temperature points during the cooling process. It is possible for two steels with the same alloy content to have different grades based on this heat treatment process.
Steel grading standards are widely used by scientists, engineers, architects, and government agencies to ensure quality and consistency of materials. These standards provide a common language to communicate the properties of steel with great specificity, and guide product manufacturers toward proper processing and application procedures. In Kenya, The Kenya Bureau of Standards has issued guidance on all steel products both locally manufactured and imported.
Benefits of using steel in construction
Steel has a unique combination of properties that make it an ideal construction material. It offers a number of significant advantages relative to other building materials, including the below:
Speed of construction
The majority of structural steelwork is prefabricated, with very little site work required other than assembly via bolted connections. This leads to fast construction times and, with attention to staged delivery, decongested construction sites, which makes it ideal for congested CBD building projects on small sites.
Unlike concrete, steel frames are full strength as soon as they are completed, allowing immediate access for following trades. Steel decking provides a safe platform immediately for work to proceed. Innovation in construction is continually improving speed and safety outcomes.
With up to 70% labor reduction possible using a steel solution compared to alternatives, fewer people equals a safer construction site. Prefabrication and dedicated lifting points on assemblies make for defined well-controlled erection processes. Steel decking and integrated edge protection facilitate safer working platforms.
Value for money
Faster construction means earlier handover and tenancy. Smaller member sizing (in particular, columns) equals greater net lettable space. Longer spans equates to more flexible internal spaces. The strength of steel, requiring fewer beams and providing more usable open space.
Robustness and ductility
Steel is an inherently ductile material, responding to overload in a controlled fashion with managed load retention. The size and shape of steel members can be configured to provide a level of structural robustness not easily achievable with other more brittle construction materials.
Prefabrication of structural steelwork is the ‘business as usual’ case. Prefabrication brings fabrication shop control over quality and the dimensional accuracy of computer numerical control (CNC) machinery. Precise control over quantities reduces waste and workflows incorporating seamless integration back to the 3D design models ensure errors are minimized
A steel structure is intrinsically lighter than an equivalent concrete structure due to the higher strength and stiffness of steel. With lightness comes reduced load on foundations, hence smaller foundations and an ability to perform better for some ground conditions. Weight reduction enables retrofitting onto existing structures for extension or refurbishment. Adding extra floors to existing structures is a common example, and architectural intent preserved.
Is reusable and endlessly recyclable
The various attributes of steel which allows for bending and reshaping resulting in creation of various other items for diverse use from construction to home décor , window panes and doors has made steel a preferred raw material in various areas.
Contains at least 25% recycled steel
Steel is often referred to as green. This is due to its recyclability levels from its mining as iron ore to its various applications.
Recycling saves both natural resources and energy and the more steel is recycled the more the environment is preserved.
The versatility of steel gives architects the freedom to achieve their most ambitious visions. Combining form and function, steel can span incredible distances and offer slenderness and refinement to create what can only be described as ‘steel sculpture’.
Architects will appreciate the opportunities for architectural expression offered by steel, such as the:
✔ clear expression of function enabled by externally exposed steel structure
✔ use of tubular members to provide efficient design with aesthetically slender members
✔ flexibility of openings in members, which can be used to accentuate ‘lightness’ or to accommodate services
✔ easy forming of curved members
✔ structural efficiency of tension members, particularly for long-span enclosures
✔ ability to design connections as ‘architectural statements’ with refined detailing
✔ flexibility of managing fire resistance of exposed steelwork, utilizing intumescent coatings, concrete filling or water filling (of tubular sections)
Given steel is assembled on site, typically with bolted connections, it’s easy to reconfigure steel elements to suit adaption of the building or structure to different purposes. The clear lines of load transfer allow strengthening and retrofitting with straightforward on-site welding. Reduced weight allows for additional floors or extensions on existing buildings. Large spans facilitate future repurposing of internal spaces with no or minimal structural modification.
Enables energy efficiency in buildings and construction projects
The energy efficiency of steelmaking facilities varies depending on production route, type of iron ore and coal used, the steel product mix, operation control technology, and material efficiency. … Steel saves energy over its many life cycles through its 100% recyclability, durability and lightweight potential.