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Repair and Remedial Work

Repair and Remedial Work

The MBT range of couplers is ideal for applications involving the replacement of corroded or damaged reinforcement as bar ends require no preparation or rotation.

MBT ET Couplers

When two MBT ET type couplers are used, the replacement bar is cut approximately 5mm shorter than the original length to allow clearance for insertion between the sound ends of the in-situ bars. MBT ET couplers are pushed fully over both ends of the replacement bar and temporarily held in position. The replacement bar is then correctly positioned and the couplers moved to a previously marked position on the existing bars indicating half the length of the coupler. The lockshear bolts are tightened to complete the installation.

The below application is suitable where the bar being replaced is at least 2 x MBT ET coupler length (see page 22) + 100mm.

Bar replacement using two MBT ET Couplers

MBT Continuity C Series Gap Closer

A smaller section of bar can be removed and replaced by an MBT Continuity C Series coupler. The central threaded stud can be modified to suit the gap. The table below provides the minimum bar length (dimension A) and minimum concrete pocket length (dimension B) to be cut away to facilitate this solution.

Bar Diameter (mm)Minimum Dimension (A)Minimum Dimension (B)
12 100 300
16 115 345
20 147 441
25 177 531
32 214 642
40 300 900

Installation

Bar replacement using MBT Continuity C Series Gap Closer

1) Orientate so threaded sections face inwards and pass the two halves of the continuity coupler over the opposing bar ends to leave the gap visible.

2) Insert appropriately sized stud in the gap and rotate each half of the coupler so the stud locates fully in each internal thread.

3) Tighten locknuts against the couplers. Shear bolt heads to complete installation by starting from the centre and working outwards and partly tightening the lockshear bolts using either a ratchet wrench or a nut runner as appropriate. Do not use impact tools. Repeat again, this time fully tightening the lockshear bolts.

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Proud Sponsors of DISC 2018

Ancon is a proud sponsor of the 6th UK DISC (Developments in Structural Concrete) Conference, taking place at the Institution of Structural Engineers in London, on 29 November 2018.