Helical cassed pull down pile as a soilder pile?
Helical cassed pull down pile as a soilder pile?
(OP)
I have a job that I am doing the concrete work and excavation and underpinning. In one corner there will be a 17' deep cut along an existing building and front sidewalk. The building will be jacked up and supported on steel so we can excavate and build new foundations. But the front corner along the sidewalk will need to be shored. The site engineers want no vibration because of the existing structure are 100+ years old rubble foundation not in good shape. The boring for that location shows fill for the first 4-5 feet N Value 12- 17, then brown clayey silt with trace of fine sand from 5-10 feet N Value 11-10, then Grey clayey silt with trace of fine sand from 10-30 feet with N Values 10-12. Ground water was at 22 feet. I have evolved an engineer to come up with some designs. I was think if it is possible to use a 1 3/4" helical pile with a 10"12"14" helices as the lead and then add an displacement plate to install a 6" Sch. 40 steel casing to be grouted solid. So I would like to install these piles as solider piles 6' OC with wood lagging total dept.35 feet so you will have a 17'6" embedment and 17'6" pile sticking up out of the cut. What I am trying to eliminate is using tiebacks or al east use a little as possible so we avoid the utilities in the street.





RE: Helical cassed pull down pile as a soilder pile?
If you need to minimize vibrations, use drilled in HP or WF soldier beams, tiedback or braced as required. Or, you could drill in larger diameter pipe soldier beams. However, the wall would still need lateral support.
It would also be nice to hear a few more details of your underpinning system.
RE: Helical cassed pull down pile as a soilder pile?
RE: Helical cassed pull down pile as a soilder pile?
The underpinning along the existing building was to been done with a traditional pit excavation concrete and dry pack. The site eng deemed the rubble wall with no footing was unstable so they decided to support on one and the end with timber cribbing placed inside the basement and timber cribbing placed outside with steel I beam carrying the load so we can demo an rebuild to the new deeper elevations needed for the new building to be built after.
I am equipped to do helical piles and helical soil nail also with some mods. My rock drill attachment can be modified to do titan bars for tie backs if necessary. So that why we are trying to do the work in house if possible if not it will be subbed out to the approved contractor.
RE: Helical cassed pull down pile as a soilder pile?
The underpinning of rubble wall sounds dicey. Granted, I have not seen it, but working with rubble is never fun. If it is very good shape you may be able to do what you are talking about, however more commonly a series of short concrete beams spliced together under the rubble and that beam is supported.
Finally, this sounds like a job for a shoring contractor and engineer wiyh experience in this sort of work. This is not the job to move into this type of work.
Question; Did Atlas & Chance merge?
RE: Helical cassed pull down pile as a soilder pile?
RE: Helical cassed pull down pile as a soilder pile?
RE: Helical cassed pull down pile as a soilder pile?
RE: Helical cassed pull down pile as a soilder pile?
RE: Helical cassed pull down pile as a soilder pile?