foundation design on structural fill

[ohyeh]

If a 2m*2m square footing will be installed on a 5 m thick structural fill, how can I get the properties of the structural fill for the settlement and bearing capacity? Is there a reference having properties for different types of structural fills? If we do test in the laboratory or in the field, what kind of test should be carried out? Basically, I want to know the bearing capacity based on settlement requirement.

 

[fattdad]

DM 7.1 or 7.2 provides typical values for compacted fills. You may want to refer to that. Mostly however, I'd say it goes by your local experience. There are local correlations between SPT and modulus, CPT and modulus or you can also use a DPT to get a modulus value. Not sure there is a simple answer. . . .

f-d

¡papá gordo ain’t no madre flaca!

 

[BigH]

oyeah: what kind of structural fill? Is it a well-graded crushed stone "base" course type of gradation compacted to, say 97% MDD (Modified)? Is it a fine to medium sand compacted to similar? Is it a clayey silt fill? The answers to these questions is important to advise on what kind of loading one would might put on. If you were to use a well-graded crushed stone "base" type of material (Say like Ontario MOT Granular A or B TypeI)properly compacted, then you could probably put on 400 kPa with settlement less than 25 mm (assuming that the base on which you sit is not "affected" by the footing - of if it is, it is reasonable "stuff". This value would be far too high if you were using a clayey silt as a structural fill - in this case 150 kPa might be attainable. You should look into the FHWA publication website as they have a manual of using bridge abutments on engineered fill: Check out the list (it is something like 15 or so listings down) at

http://www.fhwa.dot.gov/engineering/geotech/pubs