Pile Axial Capacity Enhancer

Abstract

The present disclosure addresses increasing the axial holding capacity of a pile by adding a capacity enhancer in the form of an external ring, cylindrical or otherwise, to the pile, often at the bottom of the pile. Adding the capacity enhancer to the pile increases the axial holding capacity by increasing the surface area of the pile and maximizing the use of the higher soil strength by engaging the higher strength of the deepest soil layer. The axial holding capacity is increased without increasing the overall diameter of the pile or its length, and with a very nominal increase in total weight.

What is claimed is: 
     
         1 . An apparatus for a foundation comprising:
 a first elongated member with a first length and a first cross-section; and   a second elongated member with a second length and a second cross-section,   wherein the second elongated member is connected near an end of the first elongated member, and wherein the second cross-section is greater than the first cross-section and the second length is less than the first length.   
     
     
         2 . The apparatus of  claim 1 , wherein the second elongated member is attached concentrically with the first elongated member. 
     
     
         3 . The apparatus of  claim 1  or  2 , wherein the second elongated member is connected near the end of the first elongated member that will be located in the deepest portion of the soil. 
     
     
         4 . The apparatus of any of  claims 1 - 3 , wherein the first elongated member is a cylinder and the first cross-section has a first diameter, and wherein the second elongated member is a cylinder and the second cross-section has a second diameter. 
     
     
         5 . The apparatus of any of  claims 1 - 4 , wherein the ratio of the length of the first member to the first diameter is between 0.5 to 8. 
     
     
         6 . The apparatus of any of  claims 1 - 5 , wherein the ratio of the length of the second member to the second diameter is between 0.2 to 1. 
     
     
         7 . The apparatus of any of  claims 1 - 6 , wherein the ratio of the length of the first member to the length of the second member is between 5 to 20. 
     
     
         8 . The apparatus of any of  claims 1 - 7 , wherein the ratio of the diameter of the second member to the diameter of the first member is between 1.2 to 2. 
     
     
         9 . The apparatus of any of  claims 1 - 3  and  5 - 8 , wherein the second elongated member is a polygon. 
     
     
         10 . A method of improving the axial capacity of a pile comprising:
 providing a pile with a first length and a first cross-section;   attaching a capacity enhancer with a second length and a second cross-section,   wherein the capacity enhancer is connected near an end of the pile, and wherein the second cross-section is greater than the first cross-section and the second length is less than the first length.   
     
     
         11 . The method of  claim 10 , wherein the capacity enhancer is attached concentrically with the pile. 
     
     
         12 . The method of  claim 10  or  11 , wherein the capacity enhancer is connected near the end of the pile that will be located in the deepest portion of a soil. 
     
     
         13 . The method of any of  claims 10 - 12 , wherein the pile is a cylinder and the first cross-section has a first diameter, and wherein the capacity enhancer is a cylinder and the second cross-section has a second diameter. 
     
     
         14 . The method of any of  claims 10 - 13 , wherein the ratio of the length of the pile to the first diameter is between 0.5 to 8. 
     
     
         15 . The method of any of  claims 10 - 14 , wherein the ratio of the length of the capacity enhancer to the second diameter is between 0.2 to 1. 
     
     
         16 . The method of any of  claims 10 - 15 , wherein the ratio of the length of the pile to the length of the capacity enhancer is between 5 to 20. 
     
     
         17 . The method of any of  claims 10 - 16 , wherein the ratio of the diameter of the capacity enhancer to the diameter of the pile is between 1.2 to 2. 
     
     
         18 . The method of any of  claims 10 - 12  and  14 - 17 , wherein the capacity enhancer is a polygon.