Timber Lagging Degredation
Timber Lagging Degredation
(OP)
I have a project where standard yellow pine timber lagging was used for a temporary soldier pile and lagging wall. Lagging is untreated. The owner would like the lagging removed as they are worried about voids developing long-term. It has always been my understanding that timber lagging will lose its strength over time, but not its volume, so leaving the lagging in place is not a big deal as long as it is not asked to support any loads. I cannot find a reference for this to convince the owners engineer. Can anyone confirm this and does anyone have a reference that I could provide?
Thanks for your help.
Thanks for your help.





RE: Timber Lagging Degredation
RE: Timber Lagging Degredation
Don't you have termites where you are? Wood left in the ground attracts them.
RE: Timber Lagging Degredation
http://www.eng-tips.com/viewthread.cfm?qid=109779
RE: Timber Lagging Degredation
RE: Timber Lagging Degredation
The only place I see lagging removed is the upper 2 to 4 feet below finished grade.
www.PeirceEngineering.com
RE: Timber Lagging Degredation
The real question the owner should be asking is: "To what depth does lagging need to be removed in order to meet a specified settlment criteria?"
Removal of lagging in the upper 2-4 feet will minimize any settlement immediately adjacent.
Next time, though, I would specify preservative treatment.
RE: Timber Lagging Degredation
I don't have a name of the reference, but you can google 'National Forest Service stake tests' and it should come up.
Lastly, regarding 'pine floating', it would be awfuly hard for it to float after overcoming the shear force of concrete poured against it as well as the insitu soil it was retaining when that concrete was poured.
RE: Timber Lagging Degredation
RE: Timber Lagging Degredation
My statement that pine floats was just comparing the SG of pine to the soil which is the decayed product. The decayed product is the same matter, but it occupies less volume.
RE: Timber Lagging Degredation
Except for the upper few feet of the soldier beams and lagging, a temporary sheeting wall with untreated lagging is usually abandoned in place. On permanent soldier beam walls with CIP or precast concrete facings, untreated lagging is also used and left in place. However, some owners, such as PADOT, require some minimal amount of treatment for lagging that will remain in place. Often this lagging is un-dried, hardwoods, treated only to refusal. If a permanent soldier beam wall will have exposed lagging as its finished face (which I do not recommend), then the lagging should be kiln dried, properly treated softwood.
www.PeirceEngineering.com
RE: Timber Lagging Degredation
Wedlmic