Steel Quantity in RCC Structure of Building
Steel is commonly used as reinforcement in reinforced concrete structures due to several advantages it offers. The quantity of steel used in reinforced cement concrete can be calculated based on the thumb rule according to the type of building element where it is used. Steel is used in building structures fabricated for internal support, exterior cladding and as reinforcement in RCC structures in buildings. Steel-framed buildings have steel beams and columns which generally use other materials for floors, walls, and external envelopes.
Steel buildings are used for various purposes including storage, work spaces and living accommodation. They are classified into specific types depending on how they are used. Reinforced concrete (RC), also called reinforced cement concrete (RCC) and ferroconcrete, is a composite material in which concrete’s relatively low tensile strength and ductility are compensated for by the inclusion of steel reinforcement having higher tensile strength or ductility.
Calculate Steel Reinforcement Quantity in RCC
Steel reinforcement quantity in Reinforced Cement Concrete (RCC) is calculated based on the quantity of cement concrete and the type of building element.
Advantages of Steel Reinforcement
Steel is commonly used as reinforcement in reinforced concrete structures due to several advantages it offers. Steel is used because it binds well to concrete, has a similar thermal expansion coefficient and is robust and relatively cost-effective. Reinforced concrete is also used to provide deep foundations and basements and is currently the world’s primary building material. Steel is structurally sound and manufactured to strict specifications and tolerances. Steel is a highly recyclable material, which means that steel buildings are environmentally friendly and can be easily recycled at the end of their useful life.
High tensile strength
Steel buildings can be erected much faster than traditional construction methods. This is because the components are pre-engineered and fabricated off-site, which means that construction can proceed much more quickly. One of the primary advantages of steel reinforcement is its high tensile strength. While concrete is strong in compression, it is weak in tension. By adding steel reinforcement, the composite material gains the ability to resist tensile forces. Steel reinforcement can withstand significant tensile stresses, enhancing the overall strength and structural integrity of the concrete.
Compatibility
Steel has a similar coefficient of thermal expansion to concrete, which means it expands and contracts at similar rates when subjected to temperature changes. This compatibility minimizes the risk of cracking or structural damage that can occur when materials with different expansion properties are used together.
Ductility
Steel is a highly ductile material, meaning it can undergo significant deformation before failure. This property is crucial in reinforced concrete structures because it allows the material to undergo strain without abrupt failure, giving the structure a warning sign and providing a margin of safety during overloading or seismic events.
Bonding with concrete
Steel reinforcement has excellent bonding characteristics with concrete. When properly designed and installed, the ribs or deformations on the surface of steel bars enhance the adhesion between steel and concrete. This bond transfers the stresses between the two materials effectively and ensures that the concrete and steel work together as a composite material.
Flexibility in design
Steel reinforcement provides designers with flexibility in creating complex structural configurations. Reinforcing steel can be easily shaped and bent into various forms, allowing for the creation of intricate and customized reinforcement arrangements that match the specific structural requirements. This flexibility helps optimize the design for load-bearing capacity, structural stability, and durability.
Durability
Steel reinforcement is highly durable and resistant to corrosion when properly protected. Concrete provides an alkaline environment that naturally passivates the steel, forming a protective oxide layer that prevents corrosion. Additionally, modern construction practices include proper cover and protective measures, such as concrete cover and epoxy coating, to ensure the longevity and durability of steel reinforcement.
Construction Speed and Ease
Steel reinforcement is manufactured in standard shapes and sizes, making it readily available and easy to handle on construction sites. The prefabricated nature of steel reinforcement allows for efficient installation, reducing construction time and labour costs.
Overall, steel reinforcement in reinforced concrete combines the compressive strength of concrete with the tensile strength and ductility of steel, resulting in a composite material that can withstand various types of loads and environmental conditions. It offers versatility, strength, durability, and ease of construction, making it a popular choice in the construction industry.
Disadvantages of Steel Reinforcement
While steel reinforcement offers several advantages in reinforced cement concrete (RCC) structures, there are also some disadvantages to consider. Here are a few drawbacks associated with the use of steel in RCC:
Corrosion
Despite the inherent resistance of steel to corrosion in the alkaline environment of concrete, it can still be susceptible to corrosion if it is not adequately protected. Factors such as inadequate concrete cover, exposure to aggressive environments (such as marine or industrial areas), and the presence of chlorides or carbonation can lead to the initiation and progression of corrosion. Corrosion of steel reinforcement can compromise the structural integrity of the concrete, leading to cracking, spalling, and reduced load-bearing capacity.
High thermal expansion
Steel has a relatively high coefficient of thermal expansion compared to concrete. When subjected to temperature changes, steel expands and contracts at a higher rate than concrete. This difference in thermal expansion can generate internal stresses within the RCC structure, potentially leading to cracking and deformation. Proper design considerations, such as expansion joints and temperature reinforcement, are necessary to mitigate these effects.
Susceptibility to fire
Steel loses its strength at high temperatures. In the event of a fire, the elevated temperatures can cause the steel reinforcement to weaken and potentially fail, reducing the load-carrying capacity of the RCC structure. Fire protection measures, such as fire-resistant coatings or concrete covers, must be implemented to enhance the fire resistance of steel reinforcement.
Cost
Steel reinforcement can contribute significantly to the overall cost of RCC structures, particularly in projects requiring substantial amounts of reinforcement. The cost of the steel itself, transportation, fabrication, and installation can add to the project expenses. Moreover, the price of steel reinforcement is subject to market fluctuations, which can impact project budgets.
Electromagnetic interference
Steel reinforcement can be susceptible to electromagnetic interference, particularly in structures where sensitive electronic equipment is installed. Electromagnetic fields from external sources or within the structure can induce currents in the steel. And leading to interference or damage to electronic systems. Proper shielding or insulation may be required to mitigate these effects.
Maintenance challenges
Over time, steel reinforcement may require maintenance and repair, especially in structures exposed to harsh environments or those experiencing corrosion. Assessing and repairing corroded or damaged reinforcement can be complex and costly, requiring specialized expertise and equipment.
It’s important to note that while these disadvantages exist, proper design, construction practices, and maintenance can help mitigate these issues and ensure the long-term performance of reinforced cement concrete structures.
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