A building foundation support system includes first and second components having a distal end formed with an outer surface and at least two spaced apart ribs or with at least two spaced apart grooves. When the ribs are respectively inserted into the grooves, a rotationally interlocked mechanical connection is established between the distal ends. One of the first and second components is an elongated pile shaft and the other is a drive tool coupler for driving the elongate pile shaft into the ground proximate the building foundation.

A foundation support system and method includes support components having mating ends with a pair of fastener holes and a rotational interlock feature configured to partly engage one another while the rotational interlock features are misaligned, and to self-align and fully engage the rotational interlock features via a rotation of one of the ends relative to the other while also automatically aligning the pairs of fastener holes to simplify an insertion of a fastener while avoiding fastener hole deformation when the foundation support components are driven to a desired depth on a building site to support the building foundation.

Embodiments disclosed herein include a building support system that includes a plurality of caissons that extend below building grade to one or more of an engineered depth and a competent subsurface. Each caisson is topped with a caisson cap that includes various elements and mechanisms for engaging with a structural steel member of a building module. A screw jack that operates within each caisson supports one or more building modules. Multiple screw jacks in multiple caissons raise and lower the entire building structure under electrical control, including remote control.

A hydraulic lift caisson for lifting buildings includes a pair of support columns fixed at first ends to a support column base plate and at second ends to an anchor plate, a lifting post disposed between the pair of support columns and fixed to a lifting post base plate, wherein the lifting post base plate slides along the pair of support columns, and a plurality of threaded lifting rods disposed between the support columns and the lifting post. The lifting post base plate slides along the pair of support columns together with the lifting post when the threaded lifting rods are lifted upward by hydraulic jacks disposed on the anchor plate.

A modular foundation support system includes modular foundation support components including shafts provided with integrally formed coupler features on their respective distal ends. The coupler features are configured with a non-uniform wall thickness defining a plurality of sections of respectively different diameter to matingly couple the shafts to one another in a torque transmitting relationship. The coupler features may be integrally formed and fabricated on the distal end of each respective shaft.