Pile Uplift

[cfarmer]

I am working on the design of a steel framed 4 storey office building founded on piles. I have quite significant uplift loads at the columns of the braced bays. The geotechnical engineer has provided an uplift resistance of 20% of the pile compressive resistance. With 245mm dia. steel piles this works out to a factored uplift resistance of 360kN/81 kips (Limit States design used for foundation design in Canada).
Does this seem reasonable?
Any suggestions to combat the uplift and reduce required # of piles. At all braced bay locations the # of piles is based on resisting the uplift.
I've used the resultant of the (EQ uplift less Dead load) / pile uplift resistance to determine the # of piles.

 

[cfarmer]

Info as follows was requested:
Factored pile capacities for various sizes.
Pile downdrag loads
Earthquake design data (Site classification for seismic site response - OBC 2006)
Pile uplift resistance (for uplift at braced bays)
Lateral resistance of vertical piles and allowable vertical and lateral load capacities of battered piles (various size and batter options).
Pile testing recommendations
Protections against frost
Minimim separation distances from adjacent buildings for piling operations
Foundation drainage
Slab on grade construction


To clarify the statement about "...not getting many questions about lateral resistence...". This was a geotech in another city and I had asked if he could provide a lateral resistance value of the vertical piles so that I could determine the number and location of my battered piles. Sorry for the confusion.
I wanted to know if this is typically how you handle the base shear. Are other considerations made such as grade beam/soil friction accounted for. Even with no battered piles (as I've seen some designs), the structure must still have significant lateral resistance to base shear?

Regarding the embedment depth of 7m, we've done several piling jobs in the area and have had no previous problems.

Thanks to all for the help and suggestions!