Types of Reinforcement Bars in BBS
Reinforcement bars (rebars) are essential components of reinforced concrete structures, providing the tensile strength required to counteract the forces acting on concrete. Different types of reinforcement bars, such as plain, deformed, and coated bars, are used based on the specific requirements of a project. Each type of bar is considered in the preparation of a Bar Bending Schedule (BBS).
Types of Reinforcement Bars
1. Plain Reinforcement Bars
Plain bars have a smooth surface and are typically made of mild steel. These bars are suitable for light reinforcement tasks where bond strength is not a critical factor.
- Surface: Smooth and uniform.
- Strength: Lower tensile strength compared to deformed bars.
- Applications: Used in small-scale construction, non-critical structures, and as dowels in expansion joints.
2. Deformed Reinforcement Bars
Deformed bars have a ribbed or twisted surface, providing better bonding with concrete. These are widely used in modern construction.
- Surface: Ribbed or twisted to improve the bond with concrete.
- Strength: Higher tensile strength than plain bars.
- Applications: Used in beams, columns, slabs, and other load-bearing structures.
- Examples: HYSD bars and TMT bars.
3. Coated Reinforcement Bars
Coated bars are treated with protective coatings to enhance their resistance to corrosion and other environmental factors. Common coatings include epoxy and galvanized layers.
- Types of Coatings: Epoxy-coated, galvanized, or polymer-coated.
- Durability: High resistance to corrosion, making them suitable for marine and coastal structures.
- Applications: Used in bridges, piers, water treatment plants, and other structures exposed to harsh environments.
Example of BBS with Different Types of Bars
Consider a beam reinforced using deformed and coated bars. The BBS for this beam might look like this:
| Bar Mark | Diameter (mm) | Type of Bar | Shape | Length of Each Bar (m) | Number of Bars | Total Length (m) | Weight per Meter (kg) | Total Weight (kg) |
|---|---|---|---|---|---|---|---|---|
| 1 | 16 | Deformed (TMT) | Straight | 5.0 | 12 | 60.0 | 1.580 | 94.8 |
| 2 | 12 | Epoxy-Coated | Stirrups | 1.2 | 20 | 24.0 | 0.888 | 21.312 |
In this example, TMT bars are used for the main reinforcement, while epoxy-coated bars are used for stirrups to resist corrosion in a marine environment.
Conclusion
Understanding the types of reinforcement bars is essential for selecting the right material for construction. Plain bars are suitable for light structures, deformed bars are ideal for high-strength requirements, and coated bars are essential for durability in harsh environments. Incorporating these bar types into a BBS ensures accuracy, efficiency, and quality in construction projects.