H Pile and Lagging
H Pile and Lagging
(OP)
Project: New addition with a basement going in next to an existing at grade commercial building.
To retain the soil/footing for the existing building, we are considering H piles and wood lagging next to the existing footings, then put a new concrete wall on the basement side once we get deep enough.
What happens when the lagging eventually deteriorates- is there a risk of the existing building settling?
What other options have people used for lagging in conditions like this?
Thanks
To retain the soil/footing for the existing building, we are considering H piles and wood lagging next to the existing footings, then put a new concrete wall on the basement side once we get deep enough.
What happens when the lagging eventually deteriorates- is there a risk of the existing building settling?
What other options have people used for lagging in conditions like this?
Thanks





RE: H Pile and Lagging
RE: H Pile and Lagging
A tangent pile wall was my other suggestion to the GC- but they would prefer H piles.
Unfortunately, due to the proximity of the existing building we are building next to (we are right up against the existing footings), whatever we install will need to remain in place. They will not be able to get access to the lagging to remove it
RE: H Pile and Lagging
Have you ever pulled old wooden fence posts out of the ground? They're rarely rotten more than 12" into the ground, the rest is typically in perfect shape. It's not necessarily the embedding in the ground that causes issues, it's the constant wetting and drying and being exposed to the air. So if you could get heavily treated lagging with a good clay cap on top, the deterioration may not be as bad as expected.
RE: H Pile and Lagging
RE: H Pile and Lagging
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RE: H Pile and Lagging
Unfortunately, we will be as tight as possible to the existing building footings. We will be using the for retaining only- the building support structure will be independent.
Underpinning would be be a challenge for two reasons- 1. Our new basement slab will be 6 feet or so below bottom of existing footing and 2. The existing building will be occupied during construction.
The elevations would be a challenge, but we could make it work. I don't think I want to risk this with the building being occupied however.
RE: H Pile and Lagging
PS. You also know the bending and deflection capacity of the sections with respect to equivalent fluid pressures.
Good Luck.
Durtguy
RE: H Pile and Lagging
Neither of these two reasons should be a problem for underpinning. Six feet deep underpinning is rather shallow and may not require any lateral support. Most buildings being underpinned are occupied.
www.PeirceEngineering.com