Foundation options is swampy locations
Foundation options is swampy locations
(OP)
Hi,
I am doing the structural design for a 2 storey house constructed in a very swampy location. The house is to be constructed out of 8" masonry blocks and 5" thick concrete floor slabs. I have done a few test pits and there is atleast 12 feet of "muck". Bedrock is nowhere to be seen. The site is going to be raised by about 4 feet for flood protection and the ground floor is going to be an additional 3 feet above the fill.
I am currently exploring foundation options and the raft foundation seems like a reasonable solution as opposed to more expensive options such as piling. My question however is whether the 4 feet of fill will be sufficient to distribute the loads so that I don't have any settlement issues considering that the house is heavier than a timber framed structure. If not, what would be a recommended fill layer and how far beyond the building footprint should I extend the fill layer.
Are there other economical foundation options that I can explore?
Thanks
I am doing the structural design for a 2 storey house constructed in a very swampy location. The house is to be constructed out of 8" masonry blocks and 5" thick concrete floor slabs. I have done a few test pits and there is atleast 12 feet of "muck". Bedrock is nowhere to be seen. The site is going to be raised by about 4 feet for flood protection and the ground floor is going to be an additional 3 feet above the fill.
I am currently exploring foundation options and the raft foundation seems like a reasonable solution as opposed to more expensive options such as piling. My question however is whether the 4 feet of fill will be sufficient to distribute the loads so that I don't have any settlement issues considering that the house is heavier than a timber framed structure. If not, what would be a recommended fill layer and how far beyond the building footprint should I extend the fill layer.
Are there other economical foundation options that I can explore?
Thanks





RE: Foundation options is swampy locations
RE: Foundation options is swampy locations
RE: Foundation options is swampy locations
RE: Foundation options is swampy locations
RE: Foundation options is swampy locations
Of course if the piling are point-bearing, the piling and house probably will "stay-put" (at a constant elevation) while the yard, access stairs, driveway, etc. "go down".
Sometimes sites like this are a loose-loose situation. A few months ago I had to talk a potential client out of building on a similar site.
www.SlideRuleEra.net
RE: Foundation options is swampy locations
RE: Foundation options is swampy locations
RE: Foundation options is swampy locations
I am not a big fan of surcharging organic soils for support of foundations, especially if they are thick. Sure, you can accommodate for primary and secondary consolidation, but the "tertiary" consolidation of organic soils can be significant, uneven and relatively difficult to predict.
Personally, I would either use deep foundations or get the organics out. As noted before, if deep foundations are selected, you need to be concerned about walkways, drives and especially utility connections.
RE: Foundation options is swampy locations
RE: Foundation options is swampy locations
With the raft foundation were you contemplating supporting the 5 ft thick concrete floor on columns transferring the load to the raft or a box created by grade beams. This could be expensive as well.
I am guessing here about the actual construction details. However, this is an important ingredient to your design and what approach you may want to take.
As SlideRuleEra has said sometimes you have to walk away from a site.
Problem with a house is that if cracks occur you will be readily taken to court. Litigation is high in this area and one needs to be careful and advise the owner accordingly.
RE: Foundation options is swampy locations
Time is also an issue so likely preloading and raft foundation is out. I will probably advise piling for the building foundations and removal of as much muck as practically possible along the road, sidewalk, areas
I will also be advising on a Geotech Eng to assist in the foundation design.
Thanks Again.
RE: Foundation options is swampy locations
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Foundation options is swampy locations
RE: Foundation options is swampy locations
f-d
¡papá gordo ain’t no madre flaca!
RE: Foundation options is swampy locations
RE: Foundation options is swampy locations
If any problems with the building, you should share the guilt!
Dik
RE: Foundation options is swampy locations
Design to consider the flood forces.