| Supported underpinning piers -> Monitor Keywords |
|
|
 
Supported underpinning piersRelated Patent Categories: Hydraulic And Earth Engineering, Foundation, UnderpinningSupported underpinning piers description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070048095, Supported underpinning piers. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The present invention relates to foundation support of structures via the use of supported underpinning piers. BACKGROUND [0002] Foundation underpinning is a technology used for extending a structure's foundation to a deeper elevation. There are several methods of foundation underpinning. [0003] Concrete pit underpinning consists of hand and/or machine excavated pits that are filled with concrete. The concrete pits are placed beneath an existing footing. A conventional underpinning concrete pit is a continuous concrete member that extends from the bottom of the footing to a suitable bearing stratum. [0004] FIG. 2A shows a conventional concrete pit underpinning system that utilizes concrete underpinning pits 24 placed below footings 22 to extend the building's foundation below the excavation bottom 20. FIG. 2A and 2B is a sectional view of a portion of FIG. 1, which shows a building 10 adjacent an excavation site 12. As shown in FIG. 1, soil within the excavation site has been removed to form an excavation 12 having an excavation face 14 adjacent to a wall of building 10. Numerous soil nails 16 have been placed through face 14 to form a retaining wall that can resist lateral loads formerly resisted by the excavated earth. However, temporary and even permanent retaining walls may not provide sufficient resistance to vertical loads from adjacent structures. As such, excessive settlement of structures may occur. Foundation underpinning systems are useful for reinforcing a building's foundational support proximate an excavation site. [0005] Concrete underpinning pits 24 of FIG. 2A can be machine and/or hand dug and are filled with concrete. Concrete underpinning pits can be expensive to form and can be difficult to install through ground that is hard or contains cobbles and/or boulders. Underpinning pits 24 may also be difficult to install in ground that is below the groundwater table. Even when the ground does not contain rocks or other hard materials, extensive work is needed to excavate for the pits below existing footings 22. [0006] Another type of foundation underpinning uses jack piles, which are sectional metal piles installed beneath an existing footing and attached to the footing. The jack pile is typically made of steel. The jack pile is pushed into the earth using a jack that reacts against the bottom of the existing footing. Additional sections are attached to increase the length of the jack pile. After suitable bearing stratum has been reached, the footing load is transferred to the jack piles and the jack assembly is removed. Jack piles with hollow sections may be filled with concrete or cementitious grout. [0007] A further type of foundation underpinning uses bracket piles, which are piles installed adjacent to an existing footing. The bracket pile is typically made of steel. A steel bracket attaches to the pile and extends beneath the footing to transfer load from the footing to the pile. Bracket piles are driven into the ground or are placed into a previously drilled hole and extend to a suitable bearing stratum. A bracket pile must have a section modulus large enough to support the bending moment applied by the bracket. [0008] Yet another type of foundation underpinning uses helical piles. Helical piles are sectional piles that can be installed beneath or adjacent to an existing footing. The helical piles may be made of steel. The helical piles may include a center bar around which intermittent helical plates may be connected. The helical piles may be installed by rotating the pile into the ground until a suitable bearing stratum is reached. The footing load can then be transferred to the helical pile. [0009] Similar to bracket piles, jack piles or helical piles, micropiles are also piles that may be attached to a footing. Micropiles are typically made of steel pipe filled in with cementitious grout and/or steel bars surrounded by cementitious grout, which are attached to the footing. Micropiles can be installed using rotary drilling methods. Conventional micropiles have a small diameter relative to traditional wooden or concrete piles. Hollow core injection bars, shown in FIG. 3C are a type of micropile that uses grout pumped through the hollow core to enable drilling and to bond the steel bar to the ground. Conventional micropile underpinning practice is to install micropiles adjacent to existing footings or through holes bored in existing footings. Micropiles are installed adjacent to existing footings when access for boring through the footing is limited or when the footing is too small to be bored through or too small to make an adequate connection without enlarging the footing. When placed adjacent to a footing, the micropile can be fastened to the footing via laterally extending the footing to encapsulate the upper portion of the micropile. When a micropile extends through a bored hole in a footing, a top portion of the micropile is mechanically affixed to the footing or the bored hole is grouted to affix the micropile to the footing. [0010] FIG. 2B illustrates a conventional micropile underpinning system that includes a micropile 18 extending through a footing 22 of a building 10. For the conventional micropile underpinning system shown in FIG. 2B, micropiles 18 have been placed through footings 22 of the building to extend the building's foundation to a location where adequate vertical support exists, such as below excavation bottom 20. Micropiles 18 may include drilled, driven, or jacked micropile formed from steel and cementitious grout. These micropiles depend upon shear transferred through a bored hole in the footing to provide support to the footing. In other configurations in which micropiles 18 are placed adjacent to the footings 22, the footings require extensive work to laterally extend them to encapsulate a top portion of the micropile or to otherwise fasten the micropile to the footing. [0011] For the conventional micropile underpinning system of FIG. 2B, any seismic events or lateral movement in the soil adjacent to the excavation face 14 may cause large bending moments to occur along the micropiles 18, which degrades structural support to the building. In particular, such moments can be high where the micropiles 18 connect with the footings 22 or otherwise connect to the building's foundation. [0012] U.S. Pat. No. 6,012,874 to Groneck et al. discloses a micropile casing and method according to the conventional micropile method of FIG. 2B, but which improves the connection between the micropile and the building's footing to enhance load transfer and resistance to bending moments. The Groneck system uses micropiles placed through existing footings, which nonetheless can experience high bending moments where they connect to the footings and can, thus, degrade the footings and their connection therewith over time. SUMMARY [0013] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. [0014] Aspects of the present invention relate to supported underpinning pits and related systems and to methods of foundation underpinning for a structure. According to aspects of the invention, an underpinning system may include one or more elongated support members, such as a micropile, extending from an underpinning pier below a structure's foundation. A plurality of micropiles may be coupled with the underpinning pier to substantially vertically extend the depth of the structure's foundation, as well as to reduce the potential of bending moments being applied to individual micropiles. [0015] Aspects of the invention further include methods for installing micropile supported underpinning piers and related systems. The foregoing summary of aspects of the invention, as well as the following detailed description of various embodiments, is better understood when read in conjunction with the accompanying drawings, which are included by way of example, and not by way of limitation with regard to the claimed invention. BRIEF DESCRIPTION OF THE DRAWINGS [0016] FIG. 1 is an elevational perspective view of a sample building and a portion of a sample excavation site, in which the prior art systems of FIGS. 2A and 2B and aspects of the present invention may be implemented. [0017] FIGS. 2A and 2B are sectional views of the building of FIG. 1 showing conventional concrete pit and micropile underpinning systems. [0018] FIGS. 3A and 4-6 are sectional views of the building of FIG. 1 illustrating micropile supported underpinning piers according to various aspects of the invention. [0019] FIG. 3B is a top plan view of the building of FIG. 1 showing example locations for the micropile supported underpinning piers of FIGS. 3A and 4-6. [0020] FIG. 3C is a sectional view of a hollow core injection bar that may be used with the supported underpinning piers. [0021] FIG. 7 illustrates a method for providing micropile supported underpinning to a structure according to aspects of the invention. Continue reading about Supported underpinning piers... Full patent description for Supported underpinning piers Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Supported underpinning piers patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Supported underpinning piers or other areas of interest. ### Previous Patent Application: Riser keel joint assembly Next Patent Application: Soil conditioner Industry Class: Hydraulic and earth engineering ### FreshPatents.com Support Thank you for viewing the Supported underpinning piers patent info. IP-related news and info Results in 0.17276 seconds Other interesting Feshpatents.com categories: Software: Finance , AI , Databases , Development , Document , Navigation , Error 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
