Timber Sleeper Retaining Wall
Timber Sleeper Retaining Wall
(OP)
Hi
I am being tasked with designing a retaining wall, 900mm high for a garden wall, using timber sleepers.
I have no idea how to go about this initially, I can get my soil loadings and moment applied, but not sure where to start with my resistance of this, the client is eager to use sleepers.
Do I use traditional retaining wall design, using self weight of the timber and a small lean mix base to resist this? Or do I need to design the timber for the pressure at the bottom of the wall as a beam spanning between vertical posts?
Some urgent help would be great!!!!
I am being tasked with designing a retaining wall, 900mm high for a garden wall, using timber sleepers.
I have no idea how to go about this initially, I can get my soil loadings and moment applied, but not sure where to start with my resistance of this, the client is eager to use sleepers.
Do I use traditional retaining wall design, using self weight of the timber and a small lean mix base to resist this? Or do I need to design the timber for the pressure at the bottom of the wall as a beam spanning between vertical posts?
Some urgent help would be great!!!!






RE: Timber Sleeper Retaining Wall
http://www.fairfaxcounty.gov/dpwes/publications/re...
RE: Timber Sleeper Retaining Wall
Step one -> convince the owner to not use a timber wall.
Step two -> use a segmental retaining wall (precast blocks).
We actually don't design these due to their poor performance. But if I were to -> draw your pressure diagram due to soil and surcharge, then find a load path. I assume sleepers are deadman/tieback, right? Are you planning on designing a soildier pile with tie-back type system?
This is a short wall but the dead load of the timbers is pretty small. I'm not sure what you mean by base?
That sounds reasonable, but I'm sure they will be upset about digging the holes for the posts.
EIT
www.HowToEngineer.com
RE: Timber Sleeper Retaining Wall
RFreund - I'm in a monumental battle, google has caused a war, he is a keyboard warrior (like myself now!) and found walls that have been used and is adamant he wants us to design it this way, no matter how I fight he keeps going back to these examples.
As a base I mean a small concrete plinth to build up off, nothing structural as such, but would provide some dead load, with posts cast in to this base to the rear. They are happy to have posts which is mad.
I have looked at deadmans/tie backs and would specify them, although I think he is going to be a nightmare client, because it "may cost more"!
RE: Timber Sleeper Retaining Wall
Mike McCann
MMC Engineering
RE: Timber Sleeper Retaining Wall
If the are ok to dig posts then design it as a soldier pile and lagging wall. They will probably have to embed the posts say 6'-8' oc about 1.5xH - 2xH in the ground and maybe even in concrete or some sort of pier. If you add a tie back then this embedment could be shorter. Make sure you design the connections for the appropriate pressure (near the base of the wall should be worst case). Also design the lagging to span between posts. Make sure to put some sort of drainage aggreate and perferated drain pipe wrapped in filter fabric or something to this effect.
Again I'm just not a fan of timber walls but maybe there is a place for them.
Actually it's probably not a bad idea to put in a longer tie back, this way when they have to rip it out there is room to install a proper wall...
EIT
www.HowToEngineer.com
RE: Timber Sleeper Retaining Wall
I'm not happy with it, though I have justified it as mentioned designing as a timber beam spanning between posts for the pressure applied at the bottom of the wall. With tie backs included the effective length should only be about 900mm in total so I'm reasonably satisfied. And yes, I would love him to change his mind and put a proper wall in.
RE: Timber Sleeper Retaining Wall
RE: Timber Sleeper Retaining Wall
Mike McCann
MMC Engineering
RE: Timber Sleeper Retaining Wall
RE: Timber Sleeper Retaining Wall
RE: Timber Sleeper Retaining Wall
Either way, still not a fan of timber. But I understand at 3' tall there's not much of a threat for injury.
EIT
www.HowToEngineer.com