Adjustable pier/footing cap for creating an adjustable building foundation

Abstract

I have invented an apparatus for creating an adjustable foundation, for residential and light commercial structures, that are supported on concrete drilled piers or concrete pad footing supports. The apparatus is an adjustable pier/footing cap, added to conventional drilled piers/footings at the time of foundation construction; said drilled piers are commonly used to support a building foundation in expansive soil areas and/or in other areas where upper bearing soils are weak or incompetent. The adjustable pier/footing caps are partially imbedded in the concrete drilled piers/footings when the piers/footings are poured and then into the foundation walls of the building when said foundation walls are poured. Upon settling or upheaval of the foundation, the adjustable pier/footing caps can be adjusted to lower or raise the building without replacing the drilled pier/footing with an expensive remedial piering device, and without substantial excavation around the foundation.

1 . An adjustable pier/footing cap system that adds adjustability to a conventional drilled pier/footing building foundation, comprising a plurality of steel members connected together that create an adjustable load transfer interface between the drilled pier/footing and the foundation wall; 
   
   
       2 . The adjustable pier/footing cap system of  claim 1  wherein said plurality of steel members includes a threaded rod inserted through a steel base-plate and welded thereto, said base-plate having several reinforcing steel bars attached and extending below that create a tie connection to the reinforcing steel bars typically contained in the drilled pier/footing; the base-plate being located at the top of the drilled pier, thus providing a fixed structural support; 
   
   
       3 . The adjustable pier/footing cap system of  claim 1  wherein said threaded rod extending upward from the drilled pier and base-plate, through the typical void space provided as part of conventional drilled pier/footing foundation construction, and penetrating a second, upper steel base-plate with hole centered in the plate of sufficient size to allow the threaded rod to slide through unencumbered; said upper base-plate having a steel tube welded to the upper side that creates a cavity within which the threaded rod can slide freely; said tube having several steel reinforcing bars welded thereto that extend upward into the foundation wall; said upper base-plate being located at the bottom of the foundation wall, which is also the top of the foundation void previously described; 
   
   
       4 . The adjustable pier/footing cap system of  claim 1  wherein said threaded rod containing a third plate with threaded nut welded thereto, such that the nut and plate combination spins along the exposed threads of the threaded rod within the void zone, and when raised to the position of meeting the upper base plate creates the load transfer connection between the foundation wall and the threaded rod, and consequently to the drilled pier/footing below; said adjustment plate containing holes that align with holes in the upper plate that allow for a bolted connection between the two, thus providing for continuity of load transfer in the event of uplift forces. 
   
   
       5 . The adjustable pier/footing cap system of  claim 1  wherein said adjustment plate is unbolted from the upper plate in the event of foundation movement, and the adjustment plate is rotated to raise or lower the foundation, with the assistance of temporary jacks if needed, to the desired elevation at which point the bolts are re-installed and the jacks (if used) are removed.