Traditional Method of Connecting Rebars


For more than a century, construction practices in the building of concrete structures have focused on the use of steel reinforcement to transfer tension forces. Lap splicing became the traditional method of connecting the steel reinforcing bars, largely due to a misunderstanding that lap splicing is a “no-cost” splicing. Lap splicing requires the overlapping of two parallel bars. The overlap load transfer mechanism relies on the concrete around it to transfer the load.

Lap Splicing DrawingRebar Lap Splicing

However, lap splicing is not always the proper means of connecting reinforcing bars for the following reasons:
• Use of lapped joints is time consuming in terms of design and installation
• Lead to serious congestion within the concrete due to the increased lapped rebar volume
• Lapped joints are very dependent upon the quality of the concrete for load transfer
• Poor compaction of the concrete will compromise the performance of the joint and might result in ‘honeycombs’

Rebar Congestion
Stains, corrosion and breakage of starter bars left for future extension

Mechanical Splices: The Technology for Present and Future

Today, the use of mechanical splices or widely known as coupler is superior in its load transfer to lapped splicing as it creates a direct mechanical connection between the 2 bars which is similar in its behavior to a continuous reinforcing bar.

Mechanical Splices Drawing Mechanical Splices

In general the use of mechanical splices system will:
• Improve structural integrity
• Improve design options
• Achieve an ideal balance of steel and concrete by eliminating unnecessary rebar
• Reduce the congestion and weight of the structure.
• Lessens the amount of embodied CO2
• Reduce the rebar cost as lapping uses more steel than couplers

So there are only advantages…

Neat Site
Mechanical splices avoids bend and rebend of reinforcement bar and improve site safety

Other than the benefits listed, trends toward stronger buildings, increased geography impacted by seismic zone mapping and increasing needs for safer buildings will also affect the potential value of a building. Hence, with many different types of reinforcing coupler system available in the market, designers can easily incorporate them into future plans.

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A wide range of couplers for different applications is available at Halfen Moment. As the strength of the coupler connection depends on qualitative threading of the rebars, do only rely on a serious partner who offers consistent and controlled quality threads.

Explore the range of Moment® couplers available here.

 

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August 1, 2017