Scaffolding Query
Scaffolding Query
(OP)
i'm involved in temporary works and have been asked to check the calcs of a small facade retention scaffold. my query is, how large a percentage of wall self weight should the transverse bracing be required to take? the calcs ive been given show 10%, i may be wrong but this figure seems rather small






RE: Scaffolding Query
Do not forget also to consider some amount of differential settlement; shored façades are usually besides excavations and some coordinated evaluation of the likely settlements should be included in the study; for the kind of excavation works that work well, it is likely the differential settlement center to end of any part or the whole will be less than 1/400 or otherwise cracks would start to be quite apparent.
RE: Scaffolding Query
The reason I ask is that if there is more than one, after the first lift cures and the second is applied, there may be enough strength in the first to allow arching action to occur, limiting the load seen to the scaffold. This could also be extrapolated to the lateral bracing to reduce that load.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Scaffolding Query
I used to have to calculate this type of load from scretch for concrete panels in fire.
You can reasonably think of the brick wall as a similar situation overall.
Now taking the wall as a solid straight rectangle allow for a reasonable out of plumb of say 5% or 1 in 20. Ignoring any base fixity the mass of the wall will then act at Height/20 from the centreline of the equivalent vertical wall.
You then get an overturning moment of Wt.x Ht./20
Taking the reaction at half the height you get
Rn.xHt/2 = Wt.x Ht./20
or Rn = Wt./10 or 10% of weight
I would only use this if the wall had serious out of straightness issues otherwise I would usually use half of this for an old wall and possibly none for a perfectly plumb wall.