Basic steel H pile questions

[apsix]

I'm a structural engineer looking for some basic knowledge on driven steel H piles (having only dealt with concrete CFA and driven timber piles)
1. Is there a simple relationship between Uniaxial Compressive Strength and safe bearing capacity?
2. Is the end bearing capacity based on the cross section area of the steel pile? (if so H piles seem to be at a disadvantage compared to 'solid' piles such as concrete or timber)
3. For H piles I assume the perimeter length for shaft friction would be equal to; 2 x (depth + width), is this correct?

Thanks

 

[BigH]

Suggest you check a couple of good piling books: Tomlinson's Pile Design and Construction; Chellis (old but good). If you can get Tomlinson's Foundation Design and Construction, section 8.12.2 gives a nice discussion of H-piles - also see section 7.7.2. He recommends that end-bearing base resistance in granular soils or rocks be only on the net cross-sectional area of the steel as there may not be a useful 'plug' build-up between the flanges. For skin friction in granular, the perimeter would be conservative. Chellis gives a few nice 'tricks' that can be used to increase the bearing.

 

[jheidt2543]

BigH:

Can you give a more complete citation of Chellis's book? I did find both of the Tomlinson books are available in the U.S. Pile Design and Construction is about $280 and Foundation Design and Construction is about $80. I couldn't find anything on Chellis's book.

 

[PSlem]

Pile Foundations by Robert D. Chellis, McGraw-Hill, 1961. I picked mine up used on Amazon

 

[Panars]

In Ohio (USA) it is common to use H-piles driven to rock. The piles are driven to refusal (defined as 20 blows per inch, 25 mm) and the capacity is based on the structural capacity of the steel (Fy x Area / 4). Friction type H-piles are also used, but generally only when it is necessary to penetrate a very dense granular soil layer or there are a lot of cobbles and boulders.

 

[BigH]

I've been lucky - I got my recent edition of Tomlinson's Foundation book in India for about US$8 and had my first Tomlinson Pile Book in Indonesia for about US$5. Of course, I upgraded the later for about $80. Jim - see if you know anyone going over to UK - might be able to get it cheaper. But both are excellent books. PSalem has given the Chellis book which was the original bible of piles. I remember one trick to weld steel plates between the flanges about 8 to 10 ft. up from the bottom of the pile to help give it some bearing when driving into sand. Else, it goes on for ages. Panars is correct on driving to rock - in Ontario the same thing - and also into the glacial till. On redriving in till, though, it can take off again. I've a good study of driving into till but sadly it is in deep storage and I can't get to it.
to all.