Tie bars and dowel bars are used interchangeably. But they are different.

The term dowel bar is not a new thing. It’s just the regular steel, which we extend to some length for future concrete construction. It’s more of a field name.

What are the dowel bars?

Steel reinforcement extended to a particular length for future extension in a framed structure is called a dowel bar.

Column Section

The round steel bars are provided in the concrete structure to transfer the load uniformly without restricting the joint movement.

No confusion. Let see in detail…

Where is it Used?

The dowel bar is mostly used in the column, slab, staircase design where the possible areas may extend in the future. 

For example, when you plan to pour concrete for the 6m column, you have poured 3m in a day & planned to balance concrete another day. Now the extension of the balance rod is called the Dowel bar in the column.

No, that was lap length, Right?

The lap length & dowel bar both are different. The term dowel bar is a term used to denote the extension of the rod in columns or slab.

For example, Assume a boy who is a first-class student; he also plays cricket. In this first-class student, boy e1590033112920

playing cricket specifies the characteristics of that boy. In general, he is a boy.

Development length and lap length denotes the rebar‘s specification, whereas a dowel bar is the name of that work.

The dowel bar length will be in the range of 45d to 50d (d- Dia of the bar) in the part of the structure work.

The same term is applicable for the slab, staircase & sunshade other construction parts of the structure. 

In concrete pavement

 A smooth round steel bar is provided between the two concrete elements to transfer the load without restricting the horizontal joint movement uniformly. The dowel bars are provided in equal spacing up to 250mm to 300mm rigid pavement.

These bars can accommodate the expansion happening due to the horizontal movement.

Dowel Bar Placement

Advantages of Dowel Bar

  • To avoid the disintegration of the concrete pavement due to the substantial horizontal movement.
  • Easily extend the structure if the dowel is provided, little drilling is necessary to insert the rod for the structure extension.

Typical Scenario

The dowel bar is used in reinforcement to connect the old and new concrete structures.

You would see the reinforcement bars are extended in a column over the slab level to connect the next slab.

You may aware that a steel rod has the maximum length is 12m but we cannot pour concrete up to 12m in a single moment.

So the concrete may pour to a certain length and the remaining portion will be poured after some time. Hence the steel bars are extended for joining the new and old concrete it is called dowel bar.

Happy Learning 🙂

Author

Bala is a Planning & QS Engineer working at Megha Engineering & Infrastructure Limited. He is the author, editor of Civil Planets.

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