Reinforce Existing Wood Retaining Wall
Reinforce Existing Wood Retaining Wall
(OP)
I have a friend who went ahead and built a 5' high railroad tie wall without any permits. Well, the town got involved and now obviously wants it certified by an engineer. It was built with almost no reinforcement. Any suggestions on how to reinforce the wall sufficiently? I can't find any resources anywhere for design of wood walls.
Bryan Nesteriak, P.E.
B&B Engineering
www.bbengrs.com





RE: Reinforce Existing Wood Retaining Wall
build the retaining wall using concrete. Place the railroad ties in front to cover up the concrete
RE: Reinforce Existing Wood Retaining Wall
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Reinforce Existing Wood Retaining Wall
http://www
www.SlideRuleEra.net![[idea] idea](https://www.tipmaster.com/images/idea.gif)
www.VacuumTubeEra.net
RE: Reinforce Existing Wood Retaining Wall
The information that SlideRule Era attached seems to deal with vertical, cantilevered, timber soldier beams with horizontal lagging. I would be surprised if that is how the subject wall was constructed.
www.PeirceEngineering.com
RE: Reinforce Existing Wood Retaining Wall
www.PeirceEngineering.com
RE: Reinforce Existing Wood Retaining Wall
The wall was constructed with 6x6 P.T lumber and stacked it like a typical residential railroad tie wall. Every 10' he installed 2 perpendicular ties back to a 3' long 6x6. I am exploring to see if I can add additional support since it obviously doesn't meet the standard criteria as it is so he doesn't have to remove and rebuild.
RE: Reinforce Existing Wood Retaining Wall
First drill some holes in front and set vertical posts say 4 feet deep- with tops at the wall top, maybe two posts together.
Then, where those vertical posts are added in front he ought to be able to install those utility pole anchors at some slight angle from the horizontal from near the top of the wall set sufficiently far back to provide anchorage. Tie them to those vertical posts.
The Chance anchor company may have some guidelines as to what capacity can be developed per anchor. A geotech engineer could calculate it knowing the soil conditions.
Of course the structural evaluation of the wall horizontal membersalso is involved.
RE: Reinforce Existing Wood Retaining Wall
This assumes its less invasive to remove a few timbers from the top of the wall than to drill at the base of the wall.
RE: Reinforce Existing Wood Retaining Wall
'Chance anchors' are soil nails which is mechanically stabilized earth (MSE) system. Embedment depth about 8' and spacing 2 rows at 4 feet, $300 - $500 per, plus strengthening of wall face. I don't have confidence in the longevity of the helical steel plate anchors.
Deadman anchors (tiebacks) need to be grouted to full bond length beyond the slope failure plane, about 15 feet or more, specialty equipment required, local company (Virginia) JES does a lot of these for basement walls, cost about $1000 per, spacing 2 rows at 8 feet. Load testing required, long term creep is a problem in soft cohesive soils.
I considered concrete buttresses in front of the wall. this saves some concrete material but the 'reverse cantilever' footing still needs to be continuous along length of wall and reqiures more width than a regular cantilevered footing under the wall.
I'm currently considering simply grading for a sloped embankment, no wall, but we may not have adequate room.
Also am looking at a wood 'crib' wall which will salvage a lot of the existing wood material. The crib wall design is another form of the MSE system seen with geogrids and soil nails.
HTH,
David