What is Dowel Bar? its Purpose and Uses
Dowel bar is a mild steel round and smooth bar provided in between two slabs. However, It restricts the horizontal movement of the slab. Above all, they are placed in the longitudinal direction i.e towards in traffic direction at a mid-depth of the slab.
Fig.1 – Joints Configuration of Four Lane Road
The above rough figure shows the joints configuration of Four Lane Road. Where blue colour lines are Dowel Bars and Green colour lines are Tie Bars. Most Importantly, These are used in road construction.
The maximum joint spacing in rigid pavement shall be 5m
Fig.2 – Recommended Dimensions of Dowel Bars for Rigid Pavement for and Axle Load of 10.2 T
For Example, by considering the slab thickness of 300mm
38mm dia MS Dowel Bars of 500mm length are to be used at every contraction joint spaced at 5m and at the expansion joint. The Dowel Bars shall be cut smooth with a power saw. However, these shall be cut from full-length MS rods in advance and stocked in reinforcement yard.
So, to protect Dowel Bars from corrosion, these are coated by epoxy paint or anti-corrosion treatment. These bars can be placed in pavement either by mechanical or manually.
PURPOSE
- It effectively transfers load from one slab to another slab.
- Helps to maintain two slabs at the same height.
- Reduces corner cracking.
- Improves the performance of the pavement joint.
USES
- Reduces the deflection and stresses.
- Increases the initial pavement life.
- Increases load carrying capacity of the slab.
- Dowel bar can be used in RCC slab and columns.
In conclusion, Dowel Bars are mechanically inserted by a “Dowel Bar Inserter (DBI)” with vibration into the concrete.
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Also Read: Construction Methodology of Box Culvert
