But in response to your inquiry, it depends on if you are using the pipe pile as a displacement pile or not. If there is no end cap, then it is not a displacement pile. Generally, pipe piles are installed as displacement piles with an end cap, and while placing the concrete for the pile cap, the pipe is filled with concrete.
This is the font of wisdom that is put out by the FHWA. http://www.fhwa.dot.gov/engineering/geotech/library_listing.cfm Scroll down to "Design and Construction of Driven Pile Foundations". The download was prepaid by your taxes.
If you fill it with sand, you then need to ask if you need to compact the sand. And if you need to compact the sand, how are you going to compact it and test the compaction. I am lazy, I will fill it with concrete, vibrate it, and test the cylinders in a lab.
Regards, Harold Sprague
Date: Mon, 24 Oct 2011 12:18:06 -0400
Subject: Steel Pipe Piles
I have a bridge footing supported on 24" diameter steel pipe piles. The bridge is a grade crossing (no water) and the footing is below finish grade, so the piles will have lateral support from the soils for their full height. The piles do not experience any tension.
Is it typical practice to provide a reinforced concrete plug at the top of the pile? Or just sand fill?
M. David Finley, P.E., P.A.
2086 SW Main Blvd - Suite 111
Lake City, FL 32025