Pile foundation on uncompacted sand?

I am now checking for a project that have stand-alone
R.C. foundation on uncompacted sand (15m thickness of that layer). The support reaction on column foot is about 100 Ton and I think it is better to use pile foundation instead. Am I right?

 

[Ron]

To make that assessment, you need more information than you have provided. If a geotechnical investigation has been done, the level of "compaction" of the sand as you have stated should be known. What is below the 15m of sand?

200 kips is a reasonably high column load, but not necessarily one which would require a deep foundation system. There are other parameters to consider as well. I suggest you get closely involved with the Geotechnical Engineer of Record. If you don't have one, I suggest you get one.

 

[Sean2]

I agree with Ron: you should contact a professional who will take responsibility for your foundation design.

There are other options, which may or may not suit your proposed development. The key is the level of settlement and differential settlement which will be tolerable.

For example, you may consider constructing a basement, and if your building and the service connections are reasonably tolerant, you MIGHT avoid any special foundation measures, as you load the soil at depth with a load equivalent to that of the soil you have had to remove to construct the basement. The soil hardly "knows" the building is there. However, this can only be applied in particular circumstances, and you MUST take advice before applying this solution.

Among the issues your professional adviser will explore is, as Ron has suggested, further information on the stratigraphy - i.e. what lies below the "uncompacted sand".