I have some 7x5” RSJ that I plan to use for a retaining wall, with reclaimed sleepers , at between 2.5 and 2.6m , with 1500mm high. I’m guessing 1/2 the height as depth , so 750mm in the ground ... Ground is heavy clay . Site is well drained. Does that sound ok and do those RSJ’s sound ok (they look strong enough) and is in keeping with agricultural silage pits etc. Thanks
hi its a bit like apples and trees. a bit different.. the rsj, is very strong if it is supported say 4" each end, supported 3 foot one end only, well, i don't know the maths, but it depends on how important it is ? ref the wall its holding, is it likely to try and move ? do you feel lucky ! mother nature will decide .. good luck peter
It’s just a garden wall , Heavy clay hardly moves anyway ... I recon 50% of the height in the ground , good dose of crete around the base.... should be ok . Thanks
I think you talking about building a King post wall. The lateral resistance of the wall is provided by the embedment of the posts (king posts), which in your case are RSJs. Half the retained height doesn’t sound enough. In industry, retaining walls need to be designed by calculation and be Eurocode 7 compliant (BS EN 1997-1). I realise this is probably a fairly minor wall and you want size it by eye. An embedment of RSJ at least equal to the retained height would not be unreasonable. I would also dig post holes bigger than the RSJ, fill with concrete and then plunge the RSJ in. This will give a wider bearing area in the ground for the RSJ to push against the soil. Calculations would need to be done to give you a code compliant design. A closer spacing of posts will obviously increase stability, provided the embedment is sufficient.