What is the Difference Between Plain Bars and Deformed Bars

Plain bars and deformed bars are both types of steel reinforcement used in concrete construction. When it comes to reinforcing concrete, understanding the difference between plain bars and deformed bars is very important.

What is the difference between plain bars and deformed bars? Plain bars have smooth and round surface whereas deformed bars have lugs, indentations, or ribs along their length.

Key Areas Covered

1. What are Plain Bars  
      – Definition, Properties, Use
2. What are Deformed Bars
      – Definition, Properties, Use 
3. Similarities Between Plain Bars and Deformed Bars
      – Outline of Common Features
4. Difference Between Plain Bars and Deformed Bars
      – Comparison of Key Differences
5. FAQ: Plain Bars and Deformed Bars
      – Answers to Frequently Asked Questions

Key Terms

Plain Bars, Deformed Bars

What are Plain Bars

Plain bars are steel bars with smooth and round surfaces without ridges and deformations. They bend easily. This property is used in making applications that require custom shapes, such as closed loops that hold deformed bars in place within concrete.

The property of weldability is used in instances such as when welding is required in connecting bars to extend the length. Furthermore, the production cost of plain bars is lower due to the lack of deformations on the surface. But the smooth texture creates a weaker mechanical bond with surrounding concrete.

Some applications of plain bars include spacers, dowels, lifting precast concrete and in non-structural applications. Plain bars with hooks can be embedded in precast concrete units for safe lifting and placement. They can be used for gates, railings, or other non-structural elements requiring basic reinforcement.

What are Deformed Bars

These deformed bars are made up of steel. They have deformations, lugs, indentations, or ribs along its length. These deformations define how they interact with concrete. These deformations grip the surrounding concrete and prevent them from slippering under tension or stress, creating a stronger mechanical bond.

Some applications of deformed bars include beams, columns, slabs, and foundations. Beams are horizontal structures that resist bending forces. In these structures, deformed bars take up the tension in the bottom section, which helps prevent cracking. Slabs, which are also horizontal structures, experience bending; here, deformed bars placed inside the concrete resist cracking from tension. In foundations, deformed bars help to prevent cracking and assist in weight distribution.

Similarities Between Plain Bars and Deformed Bars

1. Both are made of steel, which is a strong material.
2. They are long, slender steel bars.
3. Moreover, both have the main function of reinforcing concrete structures.

Difference Between Plain Bars and Deformed Bars

Definition

• Plain bars are steel bars with smooth and round surfaces without ridges and deformations, whereas deformed bars are steel bars with deformations, lugs, indentations, or ribs along their length.

Surface

• Plain bars have smooth surfaces, while deformed bars have lugs, ribs, or indentations along their surface.

Deformation

• The deformations on deformed bars create a better grip with surrounding concrete than that in plain bars.

Tensile Strength

• Deformed bars often have a slightly higher tensile strength compared to plain steel bars.

Slippage

• Plain steel bars are more prone to slippage within concrete than deformed bars.

Conclusion

Both plain bars and deformed bars are types of steel reinforcement used in concrete construction. The main difference between plain bars and deformed bars is that plain bars have smooth and round surface whereas deformed bars have lugs, indentations, or ribs along their length.

FAQ: Plain Bars and Deformed Bars

1. What is the advantage of deformed bar?

Deformed bars, with their ribbed texture, grip concrete better than smooth bars. This creates a stronger bond, allowing them to bear heavier loads and resist cracking. This makes them ideal for high-stress structures like bridges and buildings.

2. What is a plain bar?

A plain bar is a steel reinforcing rod with a smooth surface. It offers decent tensile strength for concrete structures. While it bonds well with concrete, its weakness lies in resisting high stress or tension.

3. Why is it called deformed bars?

The bars are intentionally given bumps, lugs, or ribs (deformations) to increase their surface area. This textured surface creates a stronger grip with surrounding concrete.

4. Where are plain bars used?

Plain bars are common in concrete elements like foundations, slabs, and beams where resisting pulling forces (tension) isn’t critical. Their smooth surface makes them easier to bend and work with for non-structural applications.

5. What is the difference between rebar and bar?

A rebar is a specific type of bar – a steel bar with ridges. These ridges (deformations) help it lock into concrete for better reinforcement, unlike smooth bars, which can slip. So, rebar is like a specialized bar for strengthening concrete.

Reference:

1. “Bond behavior of plain bar in highly ductile fiber-reinforced concrete (HDC) subjected to monotonic and repeated loading.” Journal of Building Engineering. Science Direct. 

Image Courtesy:

1. “Steel Bar” By Tudor Barker (CC BY-NC-SA 2.0) via Flickr
2. “Deformed Steel Bar Lot” (CC0) via PeakPX