Rapt: I misunderstood the initial query not knowing the hard/soft metric was at play. Thanks for the correction
ajk1: Thanks for the info, glad i don't need to deal with uncertainties like that in our supply chains
Ok, so, after much deliberation, I have a solution that passes the "sniff test";
1) soil passive bearing reaction is ignored on all stems
2) Weight of house on slab + weight of slab + weight of trapped soil between stems was considered to provide weight to resist in friction alone
End result...
Strictly speaking and in reality, you're right however I guess this boils down to what the governing code requires. Just looking through AS3600, it specifies nominal diameter, excluding ribs etc. This would lead to conservative results with the way the code is written bu American or Canadian...
The structure as a whole is best described as a 3-sided box with the open side facing a downwards slope. Total dimensions are 12m x 6m. Retaining wall is on the 3 sides enclosing, open side is for vehicle access to park under the house. Retaining wall does not extend beyond bounds of the...
Interesting and valid point. I've always assumed that both can be used because that's what i was taught as an graduate from a guy who had 25yrs experience in Iran, a highly seismic zone. This guy was a guru of industrial foundation design. Not to say he wasn't ever wrong but you've raised a very...
Sorry about that, I have been inconsistent with what I posted. I had hoped to not rely on the weight of the structure but as you pointed out, only 2 stems contributing is a more realistic scenario. In this instance, I then need to consider weight of the structure and slab also for friction...
Recalculated all of the above on the basis of only 2 stems resisting but with the additional house over contributing to friction resistance also. I'm sitting pretty happy with this now, have I missed anything major?
Yes, estimated as about 6kN/m length. Its a single storey timber house over, not a large amount of weight
Majority of the structural load is applied on a wall running perpendicular to the wall shown so, left to right in my sketch. This force is translated to the slab below and not to the...
Strong vote for Option 1 as well. I don't think this is a good application for bonding concrete to concrete, especially in a snow-prone area - the freeze-thaw action would probably result in the slab cracking up quite quickly
Regardless of what the book states, there's merit in taking the nominal diameter anyway as it is a smaller value and therefore more conservative for development lengths. AS3600 indicates nominal diameter, ignoring bar ribs
1) It takes substantial movement to mobilize passive pressure - the wall may move well over an inch before passive pressure is fully mobilized.
Correct, i'm hoping that utilising the weight of the structure over will prevent passive soil pressure being necessary. As always, conservative design...
If it helps at all Australian Code says to treat it the same as a 180° bend for development length which is 3x bar diameter bend radius + 4x bar diameter extension.
Typically I would aim for less than Span/500 deflection or 10mm, whichever is smaller. A bit more restrictive than standard requirements because bi-folds are a bit more sensitive to deflection from what builders have been telling me.
As for a weight/m2, I'm not sure I follow. Do you mean...
Hi everyone,
I've been practising for about 5 years now and have done my fair share of retaining walls and have come across something interesting. To be short, the site geology is rocky with 0.5 - 1m of residual soils over the top of the bedrock. In order to design the footing I've been...
