Checks on ties?

Eventually all of them,going up for brickies,hence the hop ups,then it's being used for rendering and windows,gutters,facia.Best part is all the ties will have to be moved to the windows as they are all in the way of the brickwork,we originally had them through the window openings but got told they had to go on the steel columns.
 
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Check couplings or Supplementary couplings?

Too right 1969scaff. Where do they get them from these days.

For your scaffold to be classed as a basic scaffold it has to be built in accordance with TG20:08 Page 21-Table 1. Otherwise it will have to be designed.

Assuming it is a general purpose basic scaffold fully boarded to Table 1.(Designation 3-5-2) bay length of 2.1m with ties at every lift and on every ledger braced frame and clad with Monarflex we need to look at TG20:08 pages 30 and 31 Table 4. in order to calculate the forces on the façade of the building.

The wind speed on the Monarflex is the governing factor on the forces applied to the scaffolding façade so assuming the wind speed is likely to reach 80 miles per hour (approx 36 metres per second) the forces applied to each tie position would be in the region of 16.7kN (approx 1670kgs) The safe height of the scaffold before a design is required is 19 Metres.

Yes 19 metres and its still a basic scaffold fully boarded and sheeted with Monarflex.

If you are boxing around a steel column or beam then the two doubles on the back of the beam would be subject to slipping forces of 16.7kN or 8.35 each.
Each tie member would be subjected to a force of 8.35kN.

BS EN 74 double couplers have a safe working load of Class A - 6.1kN and Class B - 9.1kN, Therefore 2 No. EN 74 Class B couplers would take a combined safe working load of 18.2kN. which is above the 16.7kN

You could box the beam with just 1 tie member slung under the ledger or across the two standards, using 6 No EN 74 Class B doubles would be sufficient to withstand forces of 16.7kN.

However none of this will work if the bolts on the couplings are not tightened to the requirements of EN74 which is to a torque of 50Nm (Newton Metres)

Table 8 of EN74 gives the Test parameters and specified values of the couplers.

A Double (RA) coupler Class A has a slipping force of 10kN and will start to slip at 20kN and a Class B has a slipping force of 15kN and will start to slip at 30kN.

BSEN74 – Clause 10.3.2.1 states a factor of safety to be used for steel couplings is 1.65. Therefore a Class B coupling with a slippage of 15kN has a safe working load of 9.1kN.

And another important factor is – Will the building or structure withstand the forces being imposed upon it?

Hope this helps. Ken Cain
 
Ken, thanks for that info,will wrap it round a five foot a beat it into the demics head who told us to put the checks on!!! Interestingly enough all scaffolds have to be passed by a well known scaffolding safety organisation,so it will be interesting to see what they report.At the moment our gang is back on local sites,thank the Lord,although was thinking of swapping my boots for some ice skates!!!
 
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