Patent Application
20140030029
The disclosure relates generally to foundation construction and repair and, more particularly, to a system and method for driving foundation pilings with tapered ends in connection with an apparatus that is adapted to raise and support foundation structures.
Buildings, including houses, office buildings, strip malls and the like, are often constructed such that a building frame, or other structural component, rests on a foundation. Foundation types are generally known and can include concrete slabs, reinforced concrete slabs, pier-and-beam, footings, and other types. Sometimes foundations include structures that are deep enough to contact, or tie into, solid strata such as bedrock. Other foundations are made shallow and rest on soil above the bedrock. These foundations may include structures, such as concrete slabs for example, that distribute the weight of the building across a relatively large area of the soil.
Changing soil conditions and/or improper building construction can result in portions of the building sagging or drooping. This can be caused by parts of the foundation sinking where the soil conditions are insufficient to support the structure. The sagging and drooping can, in turn, cause damage to the frame, drywall, flooring, plumbing, and other components of the building.
When a foundation structure such as a slab sinks, it becomes necessary to raise the sinking portion and support it such that it does not re-settle or sink further. Prior techniques have involved jacking up the slab and positioning pilings below the foundation for support. However, the pilings are not in contact with the solid strata, so additional foundation sinking can still occur. Additionally, these techniques can be very expensive and can be visually unpleasing as the repair components such as the pilings are typically visible after the repair work is completed.
Some prior systems involve driving a series of pipes or other foundation support structures into the ground. The pipes may be driven hydraulically or with a helix-type drive. A first pipe section is driven to a desired depth. Assuming that a ground, or downward, end of the pipe has not yet reached bedrock or some other stable strata, it is necessary to affix a second pipe section to the upward end of the first pipe section and then continue the pipe driving process. Prior systems have employed a coupling section to join the two foundation support pipe sections. The coupling section has an inner diameter slightly larger than the outer diameter of the joining ends of the two foundation support pipe sections. The coupling section overlaps the abutting joint between the two foundation support pipe sections and is affixed to the pipe sections (e.g., by weld or bolts) to join the two foundation support pipe sections.
With prior foundation support driving methods utilizing pipe sections, two respective pipe ends had to be joined using a coupling section. In these prior systems, the coupling section has an inner diameter slightly larger than the outer diameter of the joining ends of the two foundation support pipe sections. The coupling section overlaps the abutting joint between the two foundation support pipe sections and is affixed to the pipe sections (e.g., by weld or bolts) to join the two foundation support pipe sections.
It has been discovered that these prior systems are deficient for a number of reasons. First, the need for a coupling section to join two foundation support pipe sections results in additional materials and a higher cost of the system. Second, adding a coupling section makes the system more complex and, therefore, more difficult to use and install. This can result in lengthening the necessary time for foundation repair work. Third, because the two joined pipe ends have the same diameter, the pipe ends are resting on one another when driven into the ground. This does not provide particularly good stability in the overall foundation support. Although the coupling section receives some of the stress of the coupling, some of the stress can be imparted to the pipe ends.
In view of the deficiencies of prior foundation support systems, certain embodiments of the invention provide an apparatus for use in foundation support systems and methods. The apparatus may include a foundation support structure, such as a piling, which may have a plurality of sections. The sections may be pipes or any other suitable structures which may be used in the foundation support system.
A piling may have a first, lower or ground end, which may include a helix tip. The helix tip may include a plurality of helix blades that are designed to drill into the ground and pull the first piling section downward. A second, or upper, end of the first piling section has a tapered portion such that a first, or lower, end of a second piling section may be fitted onto the upper end of the first piling section, thereby creating an overlap region of the two combined piling sections. The two piling sections may be affixed to one another (e.g., by a weld, one or more bolts, or other suitable connections).
According to one example embodiment an apparatus for supporting at least a portion of a building structure is provided. The apparatus includes a piling, which has multiple piling sections. A first piling section is adapted to be coupled to a second piling section. At least one of the first and second piling sections has a first end and a second end. One of the first and second ends is adapted to be driven into strata upon which the building structure is disposed. The other of the first and second ends has a tapered portion adapted for coupling to an end of the other piling section.
In another embodiment a method is provided for driving a piling. One step of the method is driving a first end of a first piling section into strata until a predetermined length of the first piling section remains exposed above the strata. The first piling section has a second end. Another step of the method is coupling a first end of a second piling section to the exposed second end of the first piling section to form a piling structure. The first end of the second piling section has an inner diameter that is different than the inner diameter of the second end of the first piling section. At least one of the coupled ends of the first and second piling section is tapered so that at least one of the coupled ends fits inside the other of the coupled ends. Another step of the method is driving the piling structure deeper into the strata.
In another embodiment an apparatus is provided for forming a piling structure. The apparatus includes a body portion and a tapered portion extending from an end of the body portion. The body portion and the tapered portion form a first piling section. The tapered portion is adapted to couple to an end of a second piling section to create an overlap area wherein an end of one of the first and second piling sections fits inside an end of the other of the first and second piling sections to form a piling structure adapted to be driven into strata.
In another example embodiment, a piling structure is provided and includes a first piling section and a second piling section. At least one of the first and second piling sections has a tapered portion. An end of one of the first and second piling structures fits inside an end of the other of the first and second piling sections to form an overlap region where the first and second piling sections are coupled.
In another example embodiment a method for forming a piling is provided. A first piling section is driven partially into strata. A second piling section is coupled to the first piling section to form a piling structure, which may be driven further into the strata. To couple the first and second piling sections, one end of one of the first and second piling sections is fitted inside an end of the other of the first and second piling sections to form an overlap region. The piling structure may be used to support a raised foundation structure.
One or more of the embodiments may provide some, none, or all of certain of the following advantage. One advantage is that with the joining configuration of certain embodiments, no extra material is needed. This can result in less expensive and simpler foundation support systems, as well as shorter repair times.
The various embodiments may present other advantages, and may include various other features and aspects. These additional advantages, features, and aspects will be apparent to one of ordinary skill in the art from the drawings, the detailed description, and the claims.
For a more complete understanding of this disclosure and its features, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:
Various embodiments are illustrated in
Similarly, the term building structure is also not intended to be limiting and may refer to any structure that is disposed upon or above strata. Thus, the term building structure may refer to buildings, homes, office buildings, apartments, town homes, warehouses, retail buildings, storage facilities, silos, power plants, chemical facilities, industrial structures, garages, walls, piers, docks, seawalls, retaining walls, foundations, footers, concrete slabs, bridges, railroads, and/or any other type of manmade structure that may rest upon, or above, the ground or other strata.
The driving mechanism may be a hydraulic system having a drive head. Alternatively, the driving mechanism may be a helix system in which the lead piling section has a helix tip with helical blades. With this system, the piling is rotated such that the helix blades screw into the ground. While certain embodiments are described in connection with these driving mechanisms, they are examples only, and any driving mechanism may be employed. Thus, the described embodiments have applicability whenever the system utilizes multiple piling sections.
If the first piling section is driven to a maximum distance, such that the upward end is at its lowest useful point, and the lower end has not reached bedrock, a second piling section may be affixed to the first piling section. A first, or lower, end of the second section is affixed to the second, or upward, end of the first piling section. The combined piling may then be driven further into the ground. This may be repeated, with piling sections being added, until the first piling section contacts stable strata, such as bedrock, thereby meeting a predetermined amount of resistance. It should be understood that certain embodiments have usefulness in configurations where the overall piling structure is not driven into contact with bedrock. And, in these situations, a predetermined resistance causing cessation of the driving process may be less than that associated with reaching bedrock.
The upward end of each piling section may be tapered so that there is a portion of the upward end having an outer diameter that is slightly less than an inner diameter of the corresponding lower end of the piling section being connected. In this way the upward end of a given piling section is inserted into the lower end of the adjacent piling section. An overlap region is created and extends along the length of the portion of the reduced-diameter upward end of the respective piling section. The two piling sections may be affixed to one another (e.g., by weld, bolts, or other connections) in the area of the overlap region.
Certain embodiments are described in terms of one or more pipe ends being tapered and with an upper end of a lower pipe section being tapered to fit inside the lower end of an upper pipe sections. However, it should be understood that the tapered-end pipe sections may be joined with other taper configurations. For instance, the sections may be joined in a reverse direction. That is, an upper end of a pipe section may have the same diameter as the body of that section, while the lower end of the pipe section above it has a tapered end. Thus the lower end of the upper pipe section fits into the upper end of the lower pipe section. In still another alternative embodiment, the lower end of an upper pipe section has a diameter that is expanded or widened so as to fit over the upper end of the lower pipe section. In this case, the upper end of the lower pipe section may have either a diameter which is the same as the diameter of its body, or a tapered diameter. This configuration may also be reversed so that the upper end of the lower pipe section has a widened diameter to receive a lower end of the upper pipe section. Other alternatives may exist so long as one or both joined ends of respective pipe sections are tapered or widened. In certain places in the description, the terms “tapered” and “widened” are used interchangeably.
First piling section 12 may be viewed as having a first-width, or first-diameter portion 15. Section 12 also has a second-width, or second-diameter portion 17. Portion has a smaller, or reduced diameter as compared with portion 15. The first and second portions 15 and 17 both have a sidewall that is relatively parallel with the longitudinal axis of the piling section. First and second portions 15 and 17 are joined by transition portion 16. Transition portion 16 reduces the width, or outside diameter, of the first piling section 12. First piling section 12 may be viewed as having a tapered end portion 11 that extends from the beginning taper point 30 to the second end 14 of first piling section 12.
Second piling section 22 may be viewed as having a first-width, or first-diameter portion 25. Section 22 also has a second-width, or second-diameter portion 27. Portion has a smaller, or reduced diameter as compared with portion 25. The first and second portions 25 and 27 both have a sidewall that is relatively parallel with the longitudinal axis of the piling section. First and second portions 25 and 27 are joined by transition portion 26. Transition portion 26 reduces the width, or outside diameter, of the second piling section 22. Second piling section 22 may be viewed as having a tapered end portion 21 that extends from the perimeter at the beginning taper point 40 to the second end 24 of first piling section 22.
Second end 14 of first piling section 12 has an outer diameter that is slightly smaller than an inner diameter of the first end 23 of second piling section 22. Thus, second end 14 of first piling section 12 fits inside of first end 23 of second piling section 22. In this manner, second piling section 22 may be positioned onto the second end of first piling section 12. Second piling section 22 can slide down on first piling section 12 until it reaches a point in the taper portion 16 where the outer diameter of first piling section 12 is the same as the inner diameter of first end 23 of second piling section 22. At this point, second piling section 22 may move no further downwardly along first piling section 12. This stopping point is either at or slightly below the ending point 32 of the taper of first piling section 12.
The joining of first and second piling sections 12 and 22 creates an overlap region, which extends longitudinally along the combined piling sections from a point coinciding with second end 14 of first piling section 12 downward to a point coinciding with first end 23 of second piling section 22. This overlap section, among other things, provides stability to the combined piling sections. The length of the overlap section may be adjusted, for example, by increasing or decreasing the distance between second end 14 of first piling section 12 and ending point 32 of taper section 16. A longer overlap section may provide a more stable connection between the piling sections.
It should be noted that the described configuration of the taper sections is an example only. Some alternative configurations have already been described. Other configurations exist as will be apparent. For instance, the taper may begin at a certain point and have a straight-line profile ending at a second point inward toward the piling's longitudinal axis from the first point. The straight-line, or linear, profile is illustrated, for example, in
It should also be understood that the combined piling may include more than two piling sections. Multiple piling sections may be repeatedly fitted onto one another as the combined piling is driven or screwed into the ground until the lower-most end of the first piling section comes into contact with stable strata such as bedrock.
As shown in
Moreover, and particularly with respect to pilings that are helically driven, the connection between the piling sections allows the entire combined piling to be rotated without one piling section slipping or remaining stationary with respect to one or more other piling sections. For instance, if the uppermost piling section was being rotated, and if it was not affixed to the next lower piling section, the uppermost piling section might spin while the adjacent piling section already in the ground remained stationary due to the friction between its outer surface and the ground.
As mentioned previously, and as an alternative, the piling may be driven into the ground by a known hydraulic drive system. The drive system may have one or more ram units with corresponding pistons and arms driven by the pistons. Accordingly, the one or more ram units may be actuated simultaneously to cause a retracting motion of their corresponding pistons and arms, causing a clamp assembly to grab or clamp the piling and force it downward as needed. Other driving mechanisms and methods may be used as desired.
In practice, and according to another example embodiment, the first piling section is driven into the ground. At a certain distance, the lower end of the first piling section has not yet encountered bedrock or otherwise stable strata. However, the first piling section has been driven to a depth in which there is still a workable upper end. The second piling section is positioned onto the first piling section and affixed thereto. The driving process is continued driving the combined piling further into the ground. While there is still a workable upper end of the second piling, but before the piling has reached stable strata, the third piling section is positioned onto the second piling section and affixed thereto. Then the driving process is continued. Adding piling sections and repeating the driving process is continued until the lower end portion of the combined piling encounters a predetermined resistance in the ground, which is usually in the form of bedrock or otherwise stable strata, in which case the aforementioned driving process is terminated.
As illustrated in
Although the present invention has been described with several embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present invention encompass such changes and modifications as falling within the scope of the appended claims.
