Wood Tie Retaining Wall 2

[jerseyshore]

I haven't seen a new wood tie wall (formerly known as a railroad tie wall) in at least ten years, but just got the possible request to design one out of 6x6's.

I believe the last time my office designed one I was an intern and we used a full crib-style layout (deadmen were continuous for the full length of the wall). I'm pretty sure it was designed as a gravity/MSE wall using the weight of all of the soil area "inside" each crib made up of the deadmen and tiebacks.

I know most RR tie walls are not designed or built like that. Most have shorter deadmen staggered with tiebacks in alternating courses (see example photo below). Much less digging required this way.

So my question is does anyone have any resources or methods to design these things? Does that gravity/ MSE method even work if it was a full crib?

 

[StrucPatholgst]

Tallest timber retaining wall I've ever dealt with was 18 feet. And it was rotting apart. I can't imagine a gabion cage wall being too much more expensive, and it will last a life time.

 

[StrucPatholgst]

As for design, you're probably going to have more luck finding something prescriptive on a state's DOT website, like in a standards manual.

 

[StrucPatholgst]

This looks interesting.

https://waves-vagues.dfo-mpo.gc.ca/library-bibliotheque/103500.pdf

 

[jerseyshore]

I agree pham, it is definitely doable, it's just a bit surprising that there is basically no info outside of a few graphics.

80%, they are typically spiked with big nails. I think most spec's these days call for 60d nails. Years ago many used actual 7x9 railroad ties with big railroad spikes.

I went to a house recently that had a triple tiered RR tie wall in really bad shape. Probably 20' tall, 7' per tier stepped back about 2' or so. Was in really bad shape. That owner complained the wall was leaking a lot. I told her that she is lucky it is so porous because any additional water pressure and that thing is coming down.

But for this new project, it is a really small wall we're doing, 3.5ft on one side of the driveway and 2.5 ft on the other. Not sure why the town even cares honestly, usually under 4ft in a lot of NJ towns and it's a landscape item. Everyone does new segmental/MSE walls these days, but since the existing walls at this house are old RR ties, the owner wants to be as cheap as possible and replace it with basically the same thing. It's even worse IMO because PT 6x6's have that really ugly color. Weird look.

I'm just going to use one of the prescriptive designs since these walls are so short. The contractor even said they did a million of these in the 80s and 90s, but haven't seen one built in a decade. I'll do this one because it's short and I like the contractor, but not something I'm going to make a career out of.