Void form for constructing post-tensioned foundation piles

Abstract

A void form for use in constructing pile foundations is placed between the pile and the pile cap before the pile is post-tensioned. Once the pile has been tested and tensioned to design load, the void form is filled with a hardenable material to provide continuous vertical support to the foundation.

1 . A void form for a post-tensioned pile comprising:
 an upper wall and a lower wall, each having an outer peripheral edge and an inner peripheral edge;   an outer wall joining the outer peripheral edges of said upper wall and said lower wall;   an inner wall joining the inner peripheral edges of said upper wall and said lower wall;   said walls defining a chamber; and   at least two apertures in said upper wall, each adapted to receive a tube.   
   
   
       2 . The void form of  claim 1  wherein said outer wall is perpendicular to said upper and lower walls. 
   
   
       3 . The void form of  claim 1  wherein said outer wall comprises upper and lower sloped sections meeting at a ridge between said upper and lower walls. 
   
   
       4 . The void form of  claim 1  wherein said upper wall is convex. 
   
   
       5 . A method of constructing a post-tensioned pile, comprising the steps of:
 placing an anchored pile within an anchor hole;   placing a void form on top of said anchored pile;   placing a pile cap on top of said void form;   post-tensioning said anchored pile across said void form and said pile cap to a pre-determined load; and   filling said void form with hardenable material.   
   
   
       6 . The method of  claim 5 , wherein said hardenable material comprises grout. 
   
   
       7 . The method of  claim 5 , comprising the further step of placing a compressible ring around the void form. 
   
   
       8 . The method of  claim 5 , comprising the further step of leaving a top portion of an anchor in said anchored pile protruding through said pile cap. 
   
   
       9 . The method of  claim 8 , comprising the further steps of:
 leaving a recess in said pile cap around said top portion of said anchor; and   filling said recess with hardenable material after post-tensioning said anchored pile.   
   
   
       10 . The method of  claim 5  comprising the further step of providing a bar anchor effective for anchoring said anchored pile. 
   
   
       11 . The method of  claim 5  comprising the further step of providing a strand anchor effective for anchoring said anchored pile. 
   
   
       12 . Use of a void form to construct a post-tensioned pile, comprising the steps of:
 placing an anchored pile within an anchor hole;   placing said void form on top of said anchored pile;   placing a pile cap on top of said void form;   post-tensioning said anchored pile said void form and said pile cap to a pre-determined load; and   filling said void form with hardenable material.