Tips for Placement of Reinforcements in Concrete Members

The site engineer should examine clearance at stirrups and column ties that protrude beyond other reinforcement.

A clear cover between the top of the slab and the top of reinforcements must be maintained, especially if exposed to an aggressive environment as in the bridge deck slab.

In the case of double mat reinforcement, it is advised to align steel bars vertically above each other in horizontal directions to facilitate concrete pouring and consolidation.

Provide openings in the top mat reinforcement to place fresh concrete easily and prevent scattering and concrete segregation.

In case of extremely congested reinforcement, create an opening by moving congested steel bars to each side to make way for concrete placement. Move the steel bars to the previous position after concrete pouring is completed. Sometimes, the displaced bars can be left at their place if the designer approves them.

The nominal coarse aggregate size in the concrete mixture should not be greater than three-quarters of the spacing between bars to ensure the flow of concrete through steel bars and avoid honeycombing.

The head of vibrators should fit between steel bars to consolidate concrete adequately. If a small vibrator head is used, reduce the spacing between vibration points and increase vibration time. All vibrators should be functional and prevent concrete placement unless spare vibrators are available.

Stagger bar splices to ease the concrete placement.

Ensure that the splice of column ties is staggered around the corners of the column. It is not recommended to place splice of column ties above each other.

When splices are welded, make sure that the weld is of the required size and length. The bars should not be burned, or their cross-section should not be reduced due to welding.

The use of tack welding is prohibited because it weakens the bars at the tack location. If contract documents allow tack welding, it should be done by professionals. It is recommended to carry out weld tests if many welds are made.

It is common to use splicing sleeves for large bars.

The mechanical splices should be approved by the designer otherwise it is not permitted to use.

Anchor steel bars, whenever required, by bending it around another bar, by extending it to the point of zero stress, or by bending it to 90 degrees or semicircular hook of specified minimum radius.

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