Currently I have a job consisting of bored piles socketed in rock. The rock is generally close to ground surface and it is slightly weathered to fresh, high to very high strength. (Pad footing not an option due to space constraints; There is large lateral loads and bending moments)
There is a particular pier that requires 3 1200dia piles to fit within approx 4m width. In this case, the piles c/c spacing will need to be very close. I would like to know what is the recommended minimum spacing. I came across a textbook by Das that for piles in rock, the minimum spacing should be Diameter+300mm, in order to distribute the loads equally between individual pile. Can anyone second on that?
I thought of using barettes. But is it feasible to construct in rock? Noise constraints is also another issue.