Pile Support Slab Design

[stevenspm]

Hello,
I am hoping someone can help direct me to design guide or reference material. I am designing a slab that will be supported by steel piles. The slab will be constructed between two underground structures, which is why we are using piles. The pile will be driven to bedrock. I have been searching through the ACI and other codes looking for required edge distances, along with searching this forum, and I have not found much help. Are there requirements for pile edge distance from the slab to pile?

Thanks,

 

[structSU10]

CRSI publishes a pile cap design guide - the limit states for edge distance outline there would apply - you generally want to make sure you have enough edge distance to preclude punching and develop your rebar past the pile. If you are working in a tight space, add some extra edge distance to account for tolerance of pile placement.

 

[SlideRuleEra]

stevenspm - The project sounds like it will have more in common with an "underground" bridge (two pile bents [rows] supporting a one-way reinforced concrete span) than a building.
structSU10 has given a pretty good summary of pile cap design - edge distance, punching shear, and construction tolerance. For reference, a typical pile driving spec allows any piling to be horizontally out of design location by 3" in any direction.

Here is a "Structure Magazine" review of the mentioned CRSI document: Link
Note the very first sentence: "Although pile caps are an important structural element, they are generally neglected in textbooks on structural design." The publication appears to be more oriented toward pile groups than pile bents.

For light loads, a pile supported slab can be designed with thickened build-downs at piling locations instead of discrete pile caps.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[stevenspm]

Thanks for the replies and information.