Location of new foundation with old one
Location of new foundation with old one
(OP)
Hi
We are carrying out some modification in our plant for which structure is required. The location that we have selected is near any existing struture and a column.
Can anyone tell me what is the safe distance for the new foundation from existing one.
Existing foundation is have piles and for new foundation new 24" piles will be drilled which is approximately 1/2 meter away from existing foundation of column.
Abrar
We are carrying out some modification in our plant for which structure is required. The location that we have selected is near any existing struture and a column.
Can anyone tell me what is the safe distance for the new foundation from existing one.
Existing foundation is have piles and for new foundation new 24" piles will be drilled which is approximately 1/2 meter away from existing foundation of column.
Abrar





RE: Location of new foundation with old one
3 times their "diameter". If the piles in the existing structure are 24" or less then a pile spacing of 6 feet center to center (minimum) would be a starting point. You probably need a geotechnical engineer involved in the project to advise on a final decision.
Keep in mind that the distance between the existing foundation cap and the new piles is not too important - the pile SPACING is what is important.
RE: Location of new foundation with old one
You also need to be careful that excavation or drilling the new piles does not remove the lateral support of the existing piles. If you take away the dirt from one or more sides of the existing piles, you will cause an unsupported length for which the existing piles were not designed. This would reduce the pile capacity and could cause buckling.
Will you be drilling below the ground water table? Will this cause running soil and loss of ground in the drill hole near the existing piles?
RE: Location of new foundation with old one
Thanks for your reply.
Actually their is no pile under column foundation but their are piles under existing structure foundation. Pile size of existing foundation is 12", 15 m depth and the pile size for new foundation is 24” with 20 m depth. Minimum centre to centre distance between existing pile and new pile is 4.5 ft.
Depth of pile cap of existing structure foundation is above 1.6 meter below gorund level and depth of pile cap of new foundation is 2 m below ground level.
We are using reverse rotary rig for drilling of piles in which water is continuously circulated and water level is maintained to prevent caving of borehole.
1. Is there is any effect of water on existing foundations strength?
2. Is it safe to drill pile near column foundation during plant operation?
3. Is minimum distance between piles is safe?
Best regards
Abrar
RE: Location of new foundation with old one
RE: Location of new foundation with old one
On an industrial job I was involved in a man was killed (swallowed alive) by sudden earth subsidence during drilling operations. Your conditions sound like a recipe for BIG trouble.
RE: Location of new foundation with old one
RE: Location of new foundation with old one