Caissons along a property line
Caissons along a property line
(OP)
I have a foundation recommendation for caissons on a site that has buildings built up to the property line. Two questions:
1. How close can a caisson be drilled next to and adjacent building?
2. With my buildings perimeter columns going to need to be eccentric to the caisson, Would you build a haunch on the caisson, or build a strap beam to an interior caisson and cantilever it to the property line to pick up the column?
1. How close can a caisson be drilled next to and adjacent building?
2. With my buildings perimeter columns going to need to be eccentric to the caisson, Would you build a haunch on the caisson, or build a strap beam to an interior caisson and cantilever it to the property line to pick up the column?






RE: Caissons along a property line
Then I'd use a concrete cantilever beam (perpendicular to the property line) to extend across two caissons and over to the property line to pick up the column.
RE: Caissons along a property line
RE: Caissons along a property line
RE: Caissons along a property line
1) room needed from the edge of the rig to center of shaft for drilling
2) size of bell (usually 3 x shaft dia. max.)
3) drilling tolerance
RE: Caissons along a property line
Dik
RE: Caissons along a property line
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: Caissons along a property line
RE: Caissons along a property line
RE: Caissons along a property line
RE: Caissons along a property line
I assume that yes the slab on grade is also supported by the piles. But that doesn't mean you need beams, maybe pilecaps and a slab.
Are these piles "bell ended"
I usually assume a spacing of 3 x diameter, so one question is whether the adjacent building is piled and whether the pile locations are known.
RE: Caissons along a property line
Your geotech will be able to tell you about setback and spacing, since there is no general rule applicable to all soils. In some cases, such as stable, cohesive soils drilled to shallow depths, it may acceptable to drill near the property line or existing structure.
You may want to consider auger-cast or micropiles if they fulfill your needs better (i.e., drilling closer to the existing structure.) If you need closely spaced piers, you may also need to drill and place them in stages, since part of the spacing requirement is based on disturbing an empty hole by drilling another too close to it. Some of the spacing requirements are also to avoid group action (reducing capacity like block shear in a steel connection.)
RE: Caissons along a property line