Piling

This application is a continuation-in-part of our application Ser. No. 10/241,962 filed Sep. 12, 2002 now, abandoned, which is a continuation in part of our patents Ser. No. 09/275,991, filed Mar. 25, 1999, now U.S. Pat No. 6,309,143 B1 of Oct. 30, 2001 (hereafter “143”) and Ser. No. 09/947,854, filed Sep. 7, 2001, now U.S. Pat. No. 6,468,003 of Oct. 22, 2002 (hereafter “003”) and also claims priority of the following provisional applications of ours: 60/086,916 filed May 27, 1998 and 60/116,643 filed Jan. 21, 1999.

This invention relates to piling

The entire disclosure of said patents '143 and '003 is hereby incorporated herein by reference.

Also incorporated herein by reference is the entire disclosure of said application Ser. No. 10/241,962 which was published as Publication 20, US-2003-0014929-A1 on Jan. 23, 2003.

FIG. 1 is a schematic side view of the framework of a building supported by piles whose tapered sections are embedded in cohesive soil.

FIG. 2 is a view in elevation of a pile composed of a plurality (two in this case) of tapered portions butt welded together (as disclosed in '143 with respect to its FIG. 11). It also shows the hammer used to drive that pile.

FIG. 3 is a plan view of the bottom of the pile driving hammer of FIG. 2 , showing, in dashed lines, the outline of the top of the pile of FIG. 2 .

FIG. 4 is a view in elevation of groups of the piles of FIG. 2 driven into the ground and overlain by a pile cap.

FIG. 5 is a view in elevation of the top of a structure like that of FIG. 2 except that the top has been formed to a circular cross section for attachment to a circular pipe.

It has been found that the piles of this invention can provide a surprisingly high load-carrying capacity even if the pile driving is stopped when the tapered body is largely embedded in cohesive soil (such as clay or cohesive silt) rather than in granular soil. At that stage the energy needed for further driving (as measured by resistance of the pile to movement under the blows of the pile-driving hammer) is relatively small but the actual load-carrying capacity, as measured by load tests, can be much higher than that expected for such a small driving energy. This discovery makes it unnecessary, for instance and in many cases, to continue driving through the cohesive soil down into an underlying layer of granular soil. Examples 1, 2 and 3 below illustrate the driving into cohesive soil. It will be understood that, after the driving described in each of these Examples, a supported structure (such as a conventional pile cap and a building supported thereon, or the base slab of a fuel tank) is placed on the pile while the tapered body is still largely embedded in the cohesive soil layer.

As described in '143, the tapered polygonal sections can be produced by folding a single sheet of steel. '143 states that the “tapered lengths” may be fabricated in lengths of 5 to 40 feet (1.5 m to 12 m)′. With present equipment the production of the tapered structures in lengths greater than about 40 feet by folding a single sheet is relatively impractical. However, for some soil conditions and support criteria it is desirable to use still longer tapered structures, e.g. of lengths as great as about 80 feet (24 m) or longer (as noted in '143 with reference to its FIG. 11). Such tapered piles, illustrated in FIGS. 2 to 5 , nay be composed of two (or more) separately folded tapered tubes. For example, the pile may be composed of a lower tapered polygonal portion 101 , 30 feet long, having a bottom diameter of 8 inches to which is butt welded, at 102 , an upper polygonal portion 103 , 30 feet long, the diameter and cross section of the bottom 104 of that upper portion 103 being the same as the cross section of the top of portion 101 and the top 106 of the upper portion 103 having a diameter of 32 inches, so that the slope of the entire pile is 0.0167 foot per linear foot. A tip 107 is welded to the bottom of the lower portion 101 . In the piles shown in FIGS. 2 to 4 the top 106 is of polygonal cross section and driven by direct blows of a pile driving hammer having a recess 111 . The recess shown is circular in cross section and has a diameter corresponding to that of top 106 .

As shown in FIG. 5 the top 112 of the upper portion of piles like those of FIGS. 2 to 4 may be formed to circular cross section and butt welded to a circular pipe 113 in the manner described in '143. The pile is preferably driven into the ground by blows applied to the top of pipe 113 .

It is understood that the foregoing detailed description is given merely by way of illustration and that variations may be made without departing from the spirit of the invention. The Abstract is given merely for the convenience of technical researchers and is not to be given any weight with respect to the scope of the invention.