Dear Bill,

I would reply your questions with regard to deep foundation practice in Iran.

1- I remember drop hammers was used about 30 years ago for jetties designed for about 200 ton crafts in north and also South of Iran. I desined and supervised such a jetti in genaveh Iran. You may find its photo at http://www.behrah.com/comment_show.php?cid=1288.

I think drop hammers are presently abonded by engineers. However they are rarely used by local contractors to construct  temporary jetties using timber piles in the North of Iran. They are constructed in rivers and used for fishery boats.

2- I would approximately suggest 8, 2 and 90 percent for pneumatic, hydraulic, and diesel hammers respectively. Vibratory hammers are not included. I would say vibratory hammers are used in 25percent of Iranian projects. The rest are blow hammers.

Best wishes

Ali Fakher

Drop hammers are still common place in New Zealand for residential and light commercial buildings - these buldings are typically stand alone 1 to 2 stoery timber framed.  Commonly used to install end bearing timber piles 4 to 10 metres deep.