Patent application title: Post-Installed Sleeve Device For Compensating Loss Of Shear Capacity
Inventors:
Benjamin Joseph Pimentel (New York, NY, US)
IPC8 Class: AE04G2302FI
USPC Class:
52514
Class name: Static structures (e.g., buildings) with means for split-prevention or damaged part repair
Publication date: 2015-01-29
Patent application number: 20150027078
Abstract:
A post-installed sleeve device is provided for compensating loss of shear
capacity of a concrete slab due to a hole drilled in the concrete slab.
The sleeve device includes a hollow member of, for example, a cylindrical
shape, and a lower sandwich member and an upper sandwich member shaped,
for example, as ring members. The hollow member is inserted into the
drilled hole such that an upper section of the hollow member extends
above a top surface of the concrete slab. The lower sandwich member
includes an inner edge rigidly attached to a bottom edge of the hollow
member. The upper sandwich member includes an inner edge engageably
connected to the upper section of the hollow member. The upper sandwich
member and the lower sandwich member sandwich the concrete slab
surrounding the drilled hole therebetween for compensating the lost shear
capacity of the concrete slab due to the drilled hole.Claims:
1. A sleeve device for compensating loss of shear capacity of a concrete
slab due to a hole drilled in said concrete slab, said sleeve device
comprising: a hollow member inserted into said drilled hole, said hollow
member comprising an upper section extending above a top surface of said
concrete slab; a lower sandwich member comprising an inner edge rigidly
attached to a bottom edge of said hollow member; and an upper sandwich
member comprising an inner edge engageably connected to said upper
section of said hollow member, wherein said upper sandwich member and
said lower sandwich member are configured to sandwich said concrete slab
surrounding said drilled hole therebetween for compensating said loss of
said shear capacity of said concrete slab due to said drilled hole.
2. The sleeve device of claim 1, wherein said upper sandwich member and said lower sandwich member are configured to increase area of a shear critical section around said drilled hole in said concrete slab for compensating said loss of said shear capacity of said concrete slab due to said drilled hole.
3. The sleeve device of claim 1, wherein said hollow member is of a generally cylindrical shape.
4. The sleeve device of claim 1, wherein a cross section of said hollow member is of a geometric shape comprising a circular shape.
5. The sleeve device of claim 1, wherein one or more of said lower sandwich member and said upper sandwich member are ring members affixed to said hollow member, wherein said ring members are configured to transfer shear stresses through said hollow member to compensate said loss of said shear capacity of said concrete slab due to said drilled hole.
6. The sleeve device of claim 1, wherein said hollow member is configured as an extensible hollow member to be inserted into said drilled hole of a plurality of dimensions and to enable said upper sandwich member and said lower sandwich member to adjustably sandwich said concrete slab surrounding said drilled hole of said dimensions.
7. The sleeve device of claim 1, further comprising a plurality of gripping members positioned on and attached to an upper surface of said upper sandwich member, wherein said gripping members are configured to provide a grip for engageably connecting said upper sandwich member to said hollow member.
8. A sleeve device for compensating loss of shear capacity of a concrete slab due to a hole drilled in said concrete slab, said sleeve device comprising: a hollow member inserted into said drilled hole, said hollow member comprising a threaded upper section extending above a top surface of said concrete slab; a lower ring member comprising an inner edge rigidly attached to a bottom edge of said hollow member; and an upper ring member comprising an inner threaded edge engageably connected to said threaded upper section of said hollow member, wherein said upper ring member and said lower ring member are configured to sandwich said concrete slab surrounding said drilled hole therebetween for compensating said loss of said shear capacity of said concrete slab due to said drilled hole.
9. The sleeve device of claim 8, wherein said upper ring member and said lower ring member are configured to increase area of a shear critical section around said drilled hole in said concrete slab for compensating said loss of said shear capacity of said concrete slab due to said drilled hole.
10. The sleeve device of claim 8, wherein said hollow member is of a generally cylindrical shape.
11. The sleeve device of claim 8, wherein a cross section of said hollow member is of a geometric shape comprising a circular shape.
12. The sleeve device of claim 8, wherein said hollow member is configured as an extensible hollow member to be inserted into said drilled hole of a plurality of dimensions and to enable said upper ring member and said lower ring member to adjustably sandwich said concrete slab surrounding said drilled hole of said dimensions.
13. The sleeve device of claim 8, further comprising a plurality of gripping members positioned on and attached to an upper surface of said upper ring member, wherein said gripping members are configured to provide a grip for engageably connecting said upper ring member to said hollow member.
14. A method for compensating loss of shear capacity of a concrete slab due to a hole drilled in said concrete slab, said method comprising: providing a sleeve device comprising: a hollow member comprising an upper section; a lower sandwich member comprising an inner edge rigidly attached to a bottom edge of said hollow member; and an upper sandwich member comprising an inner edge engageably connectable to said upper section of said hollow member; inserting said hollow member of said sleeve device into said drilled hole of said concrete slab to rigidly contact an upper surface of said lower sandwich member of said sleeve device with a lower surface of said concrete slab, wherein said upper section of said inserted hollow member extends above a top surface of said concrete slab; engageably connecting said inner edge of said upper sandwich member of said sleeve device to said upper section of said inserted hollow member; and sandwiching said concrete slab surrounding said drilled hole by said upper sandwich member and said lower sandwich member of said sleeve device for compensating said loss of said shear capacity of said concrete slab due to said drilled hole.
15. The method of claim 14, wherein said sandwiching of said concrete slab surrounding said drilled hole by said upper sandwich member and said lower sandwich member of said sleeve device comprises: transferring a first shear stress through said concrete slab, thereby producing a first compressive force on an upper surface of said lower sandwich member; converting said first compressive force to a second shear stress from said lower sandwich member to said upper sandwich member through a wall of said hollow member; converting said second shear stress to a second compressive force from a lower surface of said upper sandwich member, said second compressive force being transferred to said top surface of said concrete slab; and converting said second compressive force to a third shear stress, said third shear stress being transferred to a supporting column.
16. The method of claim 14, wherein said upper sandwich member and said lower sandwich member of said sleeve device are configured to increase area of a shear critical section around said drilled hole in said concrete slab for compensating said loss of said shear capacity of said concrete slab due to said drilled hole.
17. The method of claim 14, wherein said hollow member of said sleeve device is of a generally cylindrical shape, and wherein a cross section of said hollow member of said sleeve device is of a geometric shape comprising a circular shape.
18. The method of claim 14, wherein said hollow member of said sleeve device is configured as an extensible hollow member to be inserted into said drilled hole of a plurality of dimensions and to enable said lower sandwich member and said upper sandwich member to adjustably sandwich said concrete slab surrounding said drilled hole of said dimensions.
19. The method of claim 14, wherein one or more of said lower sandwich member and said upper sandwich member of said sleeve device are configured as ring members affixed to said hollow member to transfer shear stresses through said hollow member to compensate said loss of said shear capacity of said concrete slab due to said drilled hole.
20. The method of claim 14, further comprising providing a grip for engageably connecting said upper sandwich member of said sleeve device to said hollow member of said sleeve device by a plurality of gripping members positioned on and attached to an upper surface of said upper sandwich member.
Description:
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and the benefit of provisional patent application No. 61/858,123 titled "Post-installed Sleeve Device For Compensating Loss Of Shear Capacity", filed in the United States Patent and Trademark Office on Jul. 25, 2013. The specification of the above referenced patent application is incorporated herein by reference in its entirety.
BACKGROUND
[0002] Concrete structures, for example, reinforced concrete flat slabs or concrete slabs are extensively used in the building construction industry. In conventional building renovations, vertical utility pipes are typically positioned adjacent to concrete columns due to architectural or mechanical requirements. To position vertical utility pipes in a concrete slab, holes have to be created in the existing concrete slab. Manual drilling is a widely adopted method to create a hole in a concrete slab, where a drill bit of a specific size is used to drill a hole of a predetermined radius and depth in the concrete slab. However, holes created by drilling reduce the shear capacity of the concrete slabs. Engineers must recalculate moment and shear capacities of the concrete slabs when sleeves are placed in close proximity to supports or concrete columns. In many cases, structural changes are required to compensate for the loss of shear capacity caused by pipe penetrations. A pipe penetration in a concrete slab may substantially reduce the shear capacity of the concrete slab and in some cases cause a shear failure.
[0003] Hence, there is a long felt but unresolved need for a post-installed sleeve device that compensates for loss of shear capacity of a reinforced concrete slab, after a hole is drilled in the reinforced concrete slab proximal to a supporting column. Moreover, there is a need for a post-installed sleeve device that allows architects and mechanical engineers more flexibility in locating mechanical piping with minimal work and effort.
SUMMARY OF THE INVENTION
[0004] This summary is provided to introduce a selection of concepts in a simplified form that are further disclosed in the detailed description of the invention. This summary is not intended to identify key or essential inventive concepts of the claimed subject matter, nor is it intended for determining the scope of the claimed subject matter.
[0005] The post-installed sleeve device disclosed herein addresses the above stated need for compensating loss of shear capacity of a reinforced concrete slab, after a hole is drilled in the reinforced concrete slab proximal to a supporting column. Moreover, the sleeve device disclosed herein allows architects and mechanical engineers more flexibility in locating mechanical piping with minimal work and effort. The sleeve device disclosed herein is a device, for example, made of metal used in an existing cast-in-place concrete structure to reinforce shear capacity of the concrete structure by attaching two sandwich members, for example, ring shaped members to an upper section and a bottom edge of the sleeve device. The sleeve device disclosed herein is configured to transfer shear stresses in the concrete slab.
[0006] The sleeve device disclosed herein comprises a hollow member, for example, of a generally cylindrical shape, a lower sandwich member, and an upper sandwich member. The hollow member is inserted into a hole drilled in the concrete slab such that an upper section of the inserted hollow member extends above the top surface of the concrete slab. The lower sandwich member comprises an inner edge rigidly attached to a bottom edge of the hollow member. The upper sandwich member comprises an inner edge engageably connected to the upper section of the hollow member. The upper sandwich member and the lower sandwich member are configured to sandwich the concrete slab surrounding the drilled hole therebetween for compensating the lost shear capacity of the concrete slab due to the drilled hole. In an embodiment, the upper sandwich member and the lower sandwich member are configured as an upper ring member and a lower ring member respectively. In this embodiment, the hollow member comprises a threaded upper section, and the upper ring member comprises an inner threaded edge that is engageably connected to the threaded upper section of the hollow member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The foregoing summary, as well as the following detailed description of the invention, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, exemplary constructions of the invention are shown in the drawings. However, the invention is not limited to the specific methods and structures disclosed herein. The description of a method step or a structure referenced by a numeral in a drawing carries over to the description of that method step or structure shown by that same numeral in any subsequent drawing herein.
[0008] FIG. 1 exemplarily illustrates a top perspective view of a post-installed sleeve device for compensating lost shear capacity of a concrete slab due to a hole drilled in the concrete slab.
[0009] FIG. 2 exemplarily illustrates a front elevation view of the post-installed sleeve device.
[0010] FIG. 3A exemplarily illustrates a sectional view of the post-installed sleeve device taken along a sectional line A-A shown in FIG. 1.
[0011] FIG. 3B exemplarily illustrates an enlarged view of a portion of the post-installed sleeve device marked X in FIG. 3A, showing threaded sections of the post-installed sleeve device.
[0012] FIG. 4 exemplarily illustrates a top plan view of the post-installed sleeve device.
[0013] FIGS. 5A-5C exemplarily illustrate insertion and assembly of the post-installed sleeve device in a hole drilled in a concrete slab for compensating loss of shear capacity of the concrete slab due to the drilled hole.
[0014] FIG. 6 exemplarily illustrates a top perspective view of multiple post-installed sleeve devices positioned in a concrete slab proximal to a supporting column.
[0015] FIG. 7 exemplarily illustrates a top plan view, showing post-installed sleeve devices of different diameters positioned in a concrete slab proximal to a supporting column.
[0016] FIG. 8 illustrates a method for compensating loss of shear capacity of a concrete slab due to a hole drilled in the concrete slab.
[0017] FIG. 9 exemplarily illustrates a side view of a concrete slab with the post-installed sleeve device inserted into a hole drilled in the concrete slab, showing a shear critical section of the concrete slab.
[0018] FIGS. 10A-10B exemplarily illustrate top plan views of a supporting column and a concrete slab of different dimensions, showing shear critical sections of the concrete slabs.
[0019] FIG. 10C exemplarily illustrates a top plan view of a supporting column and a concrete slab with a hole drilled proximal to the supporting column, and showing a shear critical section of the concrete slab.
[0020] FIG. 10D exemplarily illustrates a top plan view of a supporting column and a concrete slab with the post-installed sleeve device inserted into a hole drilled in the concrete slab, proximal to the supporting column, and showing a shear critical section of the concrete slab.
DETAILED DESCRIPTION OF THE INVENTION
[0021] FIG. 1 exemplarily illustrates a top perspective view of a post-installed sleeve device 100 for compensating lost shear capacity of a concrete slab 501 due to a hole 502 drilled in the concrete slab 501 exemplarily illustrated in FIGS. 5A-5C. As used herein, "shear capacity" refers to maximum shear stress that a concrete structure, for example, the concrete slab 501 can withstand before shear failure of the concrete structure. Also, as used herein, "shear stress" refers to an external force per unit area acting on a structure or a surface parallel to a plane of the structure or the surface. The sleeve device 100 disclosed herein is, for example, a steel sleeve device used in an existing cast-in-place reinforced concrete slab 501.
[0022] The sleeve device 100 is made of, for example, multiple types of steel with multiple tensile strengths, an alloy, or other structural material. The sleeve device 100 disclosed herein comprises a hollow member 101, a lower sandwich member, for example, a lower ring member 103, and an upper sandwich member, for example, an upper ring member 104. As used herein, "sandwich member" refers to a mechanical structure used for rigidly sandwiching the concrete slab 501 surrounding the drilled hole 502. The sandwich member is, for example, a ring shaped member, a load transfer plate, etc. For purposes of illustration, the detailed description refers to the sandwich members being configured as ring members 103 and 104 for transferring shear stresses through the hollow member 101 to compensate loss of shear capacity of the concrete slab 501 due to the drilled hole 502; however, the scope of the sleeve device 100 disclosed herein is not limited to the sandwich members being configured as the ring members 103 and 104, but may be extended to include sandwich members configured as alternate affixations comprising, for example, plates, bars, bonding agents such as epoxy adhesives, etc., and other functionally equivalent structures to transfer shear stresses from the concrete slab 501 through the hollow member 101. In an embodiment, the lower sandwich member and the upper sandwich member can be of the same type, for example, ring members 103 and 104, or of different types, for example, a combination of a ring member 103 or 104 and a plate, a combination of a ring member 103 or 104 and bars, etc.
[0023] As exemplarily illustrated in FIG. 1, the hollow member 101 is of a generally cylindrical shape. A cross section B-B of the hollow member 101 is, for example, of a circular geometric shape or another geometric shape that allows the upper sandwich member, for example, 104 to be engageably connected to the upper section 101d of the hollow member 101. The hollow member 101 defines an inner void 102 therewithin for inserting, for example, plumbing piping, mechanical piping, heavy gauge wiring, etc. The hollow member 101 is configured in multiple shapes that allow multiple insertions, for example, mechanical structures and electrical components to be inserted through the inner void 102 of the hollow member 101 that is inserted into the hole 502 drilled in the concrete slab 501, or insertions that require an opening for mechanical, architectural, or other purposes.
[0024] The hollow member 101 is inserted into a hole 502 drilled in the concrete slab 501 exemplarily illustrated in FIGS. 5A-5C. The hollow member 101 comprises a threaded upper section 101d proximal to a top edge 101a of the hollow member 101. The threaded upper section 101d of the inserted hollow member 101 extends above a top surface 501a of the concrete slab 501. The lower ring member 103 comprises an inner edge 103a also exemplarily illustrated in FIG. 3A, rigidly attached to a bottom edge 101b of the hollow member 101. The upper ring member 104 comprises an inner threaded edge 104a engageably connected to the threaded upper section 101d of the hollow member 101. In an embodiment, the sleeve device 100 comprises multiple gripping members 105 positioned on and attached to an upper surface 104b of the upper ring member 104. The gripping members 105 provide a grip for engageably connecting the upper ring member 104 to the hollow member 101. In an embodiment, the gripping members 105 are configured as rectangular tabs. The upper ring member 104 and the lower ring member 103 sandwich the concrete slab 501 surrounding the drilled hole 502 therebetween for compensating the lost shear capacity of the concrete slab 501 due to the drilled hole 502. The lower ring member 103 and the upper ring member 104 transfer shear stresses through the hollow member 101 to compensate loss of the shear capacity of the concrete slab 501 due to the drilled hole 502. In an embodiment, the shear stresses are transferred from the concrete slab 501 to the lower ring member 103 and the upper ring member 104 of the sleeve device 100, through the hollow member 101 as disclosed in the detailed description of FIG. 9.
[0025] FIG. 2 exemplarily illustrates a front elevation view of the post-installed sleeve device 100. The sleeve device 100 disclosed herein is constructed by attaching two sandwich members, for example, the ring members 103 and 104 or plates to the bottom edge 101b and the threaded upper section 101d of the hollow member 101 respectively. The hollow member 101 is inserted into a hole 502 drilled in a concrete slab 501 exemplarily illustrated in FIGS. 5A-5C, to reinforce the concrete slab 501. The hollow member 101 is, for example, made of steel. The lower ring member 103 is, for example, a metallic ring shaped plate welded to the bottom edge 101b of the hollow member 101. Welding is performed between the inner edge 103a of the lower ring member 103 exemplarily illustrated in FIG. 1, and the bottom edge 101b of the hollow member 101. The upper ring member 104 is threadably engaged to the upper section 101d of the hollow member 101.
[0026] FIG. 3A exemplarily illustrates a sectional view of the post-installed sleeve device 100 taken along a sectional line A-A shown in FIG. 1. FIG. 3B exemplarily illustrates an enlarged view of a portion of the post-installed sleeve device 100 marked X in FIG. 3A, showing threaded sections, for example, a threaded upper section 101d of the hollow member 101 and a threaded section 104d on an inner threaded edge 104a of the upper ring member 104 of the post-installed sleeve device 100. The upper ring member 104 is, for example, a metallic ring shaped plate with the threaded section 104d defined along the inner threaded edge 104a of the ring shaped plate. The threaded section 104d along the inner threaded edge 104a of the upper ring member 104 is engaged with the threaded upper section 101d of the hollow member 101 within a predetermined thickness 501g of the concrete slab 501 exemplarily illustrated in FIG. 9.
[0027] FIG. 4 exemplarily illustrates a top plan view of the post-installed sleeve device 100. The upper ring member 104 and the lower ring member 103 of the sleeve device 100 extend outward from an outer wall 101c of the hollow member 101 of the sleeve device 100 as exemplarily illustrated in FIGS. 1-2. An inner void 102 defined within the hollow member 101 of the sleeve device 100 allows insertions, for example, plumbing piping, mechanical piping, heavy gauge wiring, etc., through the hole 502 drilled in the concrete slab 501 exemplarily illustrated in FIGS. 5A-5C. The lower ring member 103 and the upper ring member 104 attach the sleeve device 100 to the concrete slab 501. The gripping members 105 attached to the upper surface 104b of the upper ring member 104 are also exemplarily illustrated in FIG. 4.
[0028] FIGS. 5A-5C exemplarily illustrate insertion and assembly of the post-installed sleeve device 100 in a hole 502 drilled in a concrete slab 501 for compensating loss of shear capacity of the concrete slab 501 due to the drilled hole 502. As exemplarily illustrated in FIG. 5A, a hole 502 is drilled in the concrete slab 501 using a drill apparatus 503. After the hole 502 is drilled in the concrete slab 501, the sleeve device 100 is inserted through the drilled hole 502 from a lower surface 501b of the concrete slab 501 such that the threaded upper section 101d of the inserted hollow member 101 extends above a top surface 501a of the concrete slab 501 as exemplarily illustrated in FIGS. 5B-5C. The upper surface 103b of the lower ring member 103 is held in rigid contact with the lower surface 501b of the concrete slab 501. The inner threaded edge 104a of the upper ring member 104 exemplarily illustrated in FIG. 3B, is engageably connected to the threaded upper section 101d of the inserted hollow member 101 to sandwich the concrete slab 501 surrounding the drilled hole 502 in the concrete slab 501 between the upper ring member 104 and the lower ring member 103. The gripping members 105 are used for tightening the upper ring member 104 down to the concrete slab 501.
[0029] In an embodiment, on inserting the hollow member 101 into the drilled hole 502, if there is a gap 504 defined between the outer wall 101c of the hollow member 101, the upper surface 103b of the lower ring member 103, and an inner surface 501c of the concrete slab 501, grout is filled in the gap 504 to ensure full contact of the sleeve device 100 with the drilled hole 502, if required. After filling the grout in the gap 504, the upper ring member 104 is engageably connected to the hollow member 101 to sandwich the concrete slab 501 surrounding the drilled hole 502 between the upper ring member 104 and the lower ring member 103.
[0030] FIG. 6 exemplarily illustrates a top perspective view of multiple post-installed sleeve devices 100a, 100b, and 100c positioned in a concrete slab 501 proximal to a supporting column 601. The sleeve devices 100a, 100b, and 100c are positioned adjacent to each other in the concrete slab 501 with the threaded upper section 101d of each hollow member 101 extending above a top surface 501a of the concrete slab 501. As exemplarily illustrated in FIG. 6, the sleeve device 100c is positioned in a perpendicular direction with respect to the other two sleeve devices 100a and 100b. The sleeve devices 100a, 100b, and 100c are used in an existing concrete slab 501 to increase slab shear capacity when penetrations, for example, drill holes 502 exemplarily illustrated in FIGS. 5A-5B, are made in the vicinity of supporting columns 601. The lower ring member 103 and the upper ring member 104 increase the size of a shear critical section 501f exemplarily illustrated in FIG. 9. As used herein, "shear critical section" refers to a section in the concrete slab 501, which defines a slab-column joint punching shear capacity. Also, as used herein, the term "shear capacity" refers to an ability of a concrete structure to withstand a maximum shear stress before occurrence of a shear failure in the concrete structure. The lower ring member 103 and the upper ring member 104 can prevent shear failure within a predefined threshold range of the sleeve device 100a, or 100b, or 100c, thereby reinforcing the shear capacity of the concrete slab 501. The "threshold range" of the sleeve device 100a, or 100b, or 100c is defined by the American Concrete Institute (ACI) in Building Code Requirements for Structural Concrete, ACI 318, chapter 11.
[0031] Consider an example where a concrete slab 501 is positioned such that an edge 501e of the concrete slab 501 is proximal to a supporting column 601, and an edge 501d of the concrete slab 501 is distal to the supporting column 601. A hole 502 exemplarily illustrated in FIGS. 5A-5B, proximal to the supporting column 601, is drilled in the concrete slab 501. After drilling the hole 502, the concrete slab 501 experiences shear stresses 602 and 603 around the drilled hole 502 that are perpendicular to the top surface 501a of the concrete slab 501. As loads on the edge 501d of the concrete slab 501 increase, the shear stresses 602 and 603 at the drilled hole 502 also increase, thereby increasing risk of a shear failure in the concrete slab 501 at the drilled hole 502. To prevent the shear failure of the concrete slab 501, the post-installed sleeve device, for example, 100c exemplarily illustrated in FIG. 6, is inserted into the drilled hole 502 such that the upper surface 103b of the lower ring member 103 is held in rigid contact with the lower surface 501b of the concrete slab 501. The inner threaded edge 104a of the upper ring member 104 is then engageably connected to the threaded upper section 101d of the hollow member 101 as exemplarily illustrated in FIG. 3B. The upper ring member 104 and the lower ring member 103 of the sleeve device 100c sandwich the concrete slab 501 surrounding the drilled hole 502, thereby increasing area of the shear critical section 501f exemplarily illustrated in FIG. 9, around the drilled hole 502 in the concrete slab 501.
[0032] An average shear stress (v) is defined as force (F) per unit area (A) in accordance with the formula below:
ν≡(F/A)
[0033] The shear force F acts on an area A. This area A is the area of the shear critical section 501f around the drilled hole 502 as exemplarily illustrated in FIG. 10C. As the average shear stress ν is inversely proportional to the area A, the shear stress v increases if the area A is decreased. Hence, drilling a hole 502 in the concrete slab 501 proximal to a supporting column 601 reduces the area A, thereby increasing the shear stress ν. The lost shear capacity can be defined as the area of the drilled hole 502 multiplied by the original shear stress v that the concrete slab 501 experienced before drilling the hole 502. By introducing the sleeve device 100a, or 100b, or 100c into the drilled hole 502, the lost shear capacity can be compensated for through the added shear capacity of the sleeve device 100a, or 100b, or 100c. Hence, as a result of sandwiching of the concrete slab 501 surrounding the drilled hole 502, by the upper ring member 104 and the lower ring member 103 of the sleeve device 100a, or 100b, or 100c, the area A or the area of the shear critical section 501f around the drilled hole 502 increases, thereby decreasing the shear stresses 602 and 603 at the drilled hole 502. Since the upper ring member 104 and the lower ring member 103 increase the area of the shear critical section 501f around the drilled hole 502 in the concrete slab 501, the concentration of the shear stresses 602 and 603 exerted at the drilled hole 502 decreases. The sleeve device 100a, and/or 100b, and/or 100c thus strengthens the shear capacity of the concrete slab 501 surrounding the drilled hole 502 to mitigate risk of a shear failure of the concrete slab 501 by compensating the lost shear capacity of the concrete slab 501 due to the drilled hole 502.
[0034] FIG. 7 exemplarily illustrates a top plan view, showing post-installed sleeve devices 100a and 100b of different diameters D1 and D2 respectively, positioned in a concrete slab 501 exemplarily illustrated in FIG. 6, proximal to a supporting column 601. In an embodiment, the hollow member 101 of the sleeve device 100a or 100b is configured as an extensible hollow member 101 to be inserted into a drilled hole 502 exemplarily illustrated in FIGS. 5A-5B, of different dimensions and to enable the upper ring member 104 and the lower ring member 103 of each of the sleeve devices 100a and 100b to adjustably sandwich the concrete slab 501 surrounding the drilled hole 502 of multiple dimensions. The diameters of the extensible hollow members 101 of the post-installed sleeve devices 100a and 100b may be D1 or D2 based on multiple parameters, for example, physical dimensions such as diameter or circumference of the drilled hole 502, thickness 501g of the concrete slab 501 exemplarily illustrated in FIG. 9, etc.
[0035] FIG. 8 illustrates a method for compensating loss of shear capacity of a concrete slab 501 due to a hole 502 drilled in the concrete slab 501 exemplarily illustrated in FIGS. 5A-5C. A post-installed sleeve device 100 comprising a hollow member 101, an upper sandwich member, for example, an upper ring member 104, and a lower sandwich member, for example, a lower ring member 103 as exemplarily illustrated in FIGS. 1-4 and as disclosed in the detailed description of FIGS. 1-7, is provided 801. The hollow member 101 of the sleeve device 100 is inserted 802 into the drilled hole 502 of the concrete slab 501 to rigidly contact an upper surface 103b of the lower sandwich member of the sleeve device 100 with a lower surface 501b of the concrete slab 501. The upper section 101d of the inserted hollow member 101 extends above a top surface 501a of the concrete slab 501. An inner edge 104a of the upper sandwich member of the sleeve device 100 is engageably connected 803 to the upper section 101d of the inserted hollow member 101. The upper sandwich member and the lower sandwich member sandwich 804 the concrete slab 501 surrounding the drilled hole 502 therebetween for compensating the loss of shear capacity of the concrete slab 501 due to the drilled hole 502. Due to the sandwiching 804 of the concrete slab 501 surrounding the drilled hole 502 by the upper sandwich member and the lower sandwich member of the sleeve device 100, a shear stress is transferred 804a through the concrete slab 501, thereby producing a compressive force caused by shear in the concrete slab 501 on an upper surface 103b of the lower sandwich member. As used herein, "compressive force" refers to a force resulting from compression of two members against each other, causing transfer of load through bearing from one member to the other member. For example, a compressive force results from the compression in between the lower surface 501b of the concrete slab 501 and the upper surface 103b of the lower ring member 103 exemplarily illustrated in FIG. 9. The shear stress in the concrete slab 501 causes the compressive force. The compressive force is then converted 804b to a shear stress from the lower sandwich member to the upper sandwich member through the outer wall 101c of the hollow member 101. The shear stress is then converted 804c to a compressive force from the lower surface 104c of the upper sandwich member. The compressive force is transferred 804c to the top surface 501a of the concrete slab 501. The compressive force is then converted 804d to a shear stress which is transferred 804d to a supporting column 601 exemplarily illustrated in FIG. 9.
[0036] FIG. 9 exemplarily illustrates a side view of a concrete slab 501 with the post-installed sleeve device 100 inserted into a hole 502 drilled in the concrete slab 501 exemplarily illustrated in FIGS. 5A-5B, showing a shear critical section 501f of the concrete slab 501. The shear critical section 501f is defined as an area located at a distance (d/2), referenced by 501h in FIG. 9, from a supporting column 601, where "d" is the thickness 501g of the concrete slab 501. The positioning of the shear critical section 501f in the concrete slab 501 at a distance "y" from the supporting column 601 is therefore, defined by a 1:2 slope triangle of height equal to the thickness 501g of the concrete slab 501 and base 501h equal to half of the thickness 501g of the concrete slab 501, where "y" is the hypotenuse of the 1:2 slope triangle. The sandwiching of the concrete slab 501 surrounding the drilled hole 502 by the upper ring member 104 and the lower ring member 103 of the sleeve device 100, transfers a shear stress 901 through the concrete slab 501, thereby producing a compressive force 902 on an upper surface 103b of the lower ring member 103. The compressive force 902 is then converted to a shear stress 903 from the lower ring member 103 to the upper ring member 104 through an outer wall 101c of the hollow member 101. The shear stress 903 is then converted to a compressive force 904 from the lower surface 104c of the upper ring member 104. The compressive force 904 is transferred to the top surface 501a of the concrete slab 501. Thus, the compressive force 902 occurs distal to the supporting column 601, while the compressive force 904 occurs proximal to the supporting column 601. The concrete slab 501 imposes the compressive force 902 from the lower surface 501b of the concrete slab 501 onto the upper surface 103b of the lower ring member 103, and the sleeve device 100 imposes the compressive force 904 from the lower surface 104c of the upper ring member 104 onto the top surface 501a of the concrete slab 501. The compressive force 904 is converted to a shear stress 905. The shear stress 905 is transferred to the supporting column 601. Thus, by sandwiching the concrete slab 501 at the drilled hole 502, the shear stress 901 distal to the supporting column 601 is transferred through the hollow member 101 and proximal to the supporting column 601.
[0037] FIGS. 10A-10B exemplarily illustrate top plan views of a supporting column 601 and a concrete slab 501 of different dimensions, showing shear critical sections 501f of the concrete slabs 501. The concrete slabs 501 exemplarily illustrated in FIGS. 10A-10B are free of penetrations. Consider an example where a concrete slab 501 of thickness (d), for example, 1 foot ('), that is, 12 inches ('') is supported by a supporting column 601 as exemplarily illustrated in FIG. 9. Consider the shear critical section 501f to be at a distance (d/2) away from the supporting column 601 and is therefore 6'' from the supporting column 601. The area (A) of the shear critical section 501f can be calculated by multiplying the perimeter (P) of the shear critical section 501f at a distance (d/2) from the supporting column 601 with the thickness (d) of the concrete slab 501 in accordance with the formula below:
A=(P*d)
[0038] Therefore, as exemplarily illustrated in FIG. 10A, the area (A) of the shear critical section 501f is [(34''+34''+31''+31'')*12'']=1560 square inches.
[0039] Consider another example where the concrete slab 501 of thickness (d) 12'' is supported by a supporting column 601 of dimensions 1' by 1', that is, 12'' by 12'' as exemplarily illustrated in FIG. 10B. Consider the shear critical section 501f to be at a distance (d/2) away from the supporting column 601 and is therefore 6'' from the supporting column 601. The perimeter (P) of the shear critical section 501f can be calculated as 2'*4, that is, 24''*4. The area (A) of the shear critical section 501f is a multiplication product of the perimeter (P) of the shear critical section 501f and the thickness (d) of the concrete slab 501. Therefore, the area (A) of the shear critical section 501f is [(24''*4)*12'']=1152 square inches.
[0040] Nominal shear capacity (Vn) of the concrete slab 501 at the supporting column 601 is the sum of shear capacity (Vc) of the concrete slab 501 and shear capacity (Vs) of shear reinforcement, that is, the sleeve device 100 in accordance with the formula below:
Vn=Vc+Vs
[0041] The shear capacity (Vc) of the concrete slab 501 is 4 times the multiplication product of the area (A) of the shear critical section 501f and the square root of the strength (f'c) of the concrete slab 501 in accordance with the formula below:
Vc=A*4* {square root over (f'c)}
where f'c is the strength of the concrete slab 501, for example, about 5000 pounds per square inch (psi). Therefore, the shear capacity (Vc) of the concrete slab 501 having the shear critical section 501f exemplarily illustrated in FIG. 10B, is 1152*4* 5000=325835 lbs. The shear capacity (Vs) of the sleeve device 100 is zero since the concrete slab 501 exemplarily illustrated in FIG. 10B, is free of penetrations and therefore free of the sleeve device 100. Therefore, the nominal shear capacity (Vn) of the concrete slab 501 at the supporting column 601 is 325835+0=325835 lbs.
[0042] FIG. 10C exemplarily illustrates a top plan view of a supporting column 601 and a concrete slab 501 with a hole 502 drilled proximal to the supporting column 601, and showing a shear critical section 501f of the concrete slab 501. Consider an 8'' core hole 502 drilled in the concrete slab 501 of thickness (d) 12'' having a strength of 5000 pounds per square inch (psi) as exemplarily illustrated in FIG. 10C. The area (A) of the shear critical section 501f is then calculated as A=[(24''*4)-8'']*12''=1056 square inches. The shear capacity (Vc) of the concrete slab 501 can then be calculated as 1056*4* 5000=298682 lbs. Therefore, the nominal shear capacity (Vn) of the concrete slab 501 at the supporting column 601 is 298682+=298682 lbs because the sleeve device 100 is not inserted into the hole 502. Thus, the 8'' core drilled hole 502 reduces the nominal shear capacity (Vn) of the concrete slab 501 at the supporting column 601 by 27153 lbs.
[0043] FIG. 10D exemplarily illustrates a top plan view of a supporting column 601 and a concrete slab 501 with the post-installed sleeve device 100 inserted into a hole 502 drilled in the concrete slab 501 exemplarily illustrated in FIG. 10C, proximal to the supporting column 601, and showing a shear critical section 501f of the concrete slab 501. The ring members 103 and 104 of the sleeve device 100, exemplarily illustrated in FIG. 1, are configured to sandwich the concrete slab 501 surrounding the drilled hole 502, thereby compensating for the lost nominal shear capacity (Vn) of the concrete slab 501 at the supporting column 601 due to the drilled hole 502. The relatively stiffer sleeve device 100 confines the sandwiched concrete slab 501 surrounding the drilled hole 502, thereby eliminating shear failure within the confined concrete slab 501 surrounding the drilled hole 502. Thus, the sleeve device 100 bridges the penetration created in the concrete slab 501 due to the drilled hole 502 and increases the perimeter (P) of the shear critical section 501f of the slab-column connection. Consider the sleeve device 100 is a rigid sleeve device and the associated deformation of the sleeve device 100 is negligible under shear forces. The enhanced shear capacity of the sleeve device 100 that is required to compensate the lost nominal shear capacity (Vn) is controlled by the thickness of the ring members 103 and 104 of the sleeve device 100. When the sleeve device 100 is inserted into the drilled hole 502 and is configured to provide for the lost nominal shear capacity (Vn)=27153 lbs of the concrete slab 501 due to the drilled hole 502, the total nominal shear capacity (Vn) of the concrete slab 501 at the supporting column 601 becomes equal to or larger than the nominal shear capacity (Vn)=325835 lbs of the concrete slab 501 at the supporting column 601 before penetration of the concrete slab 501 with a drilled hole 502. Thus, the sleeve device 100 compensates the lost shear capacity of the concrete slab 501 due to the drilled hole 502.
[0044] Consider an example where a sleeve device 100 is configured as a steel sleeve device to provide a shear capacity (Vs)=27153 lbs for compensating the lost nominal shear capacity (Vn) of the concrete slab 501 at the supporting column 601. To provide this compensation, steel area (As) of each of the ring members 103 and 104 of the steel sleeve device 100 exemplarily illustrated in FIGS. 1-2, is configured in accordance with the formula below:
As=Vs/(0.4*ft)
where "fy" is the design yield strength of the steel used to configure the ring members 103 and 104. Consider "fy" as 60000 psi. Therefore, the steel area (As) is [(27153)/(0.4* 60000)]=1.13 square inches. As long as each of the ring members 103 and 104 of the sleeve device 100 is configured with the area (As) required for effective shear force transfer width, the shear capacity (Vn) lost due to penetration of the concrete slab 501 with the drilled hole 502 can be compensated.
[0045] The foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention disclosed herein. While the invention has been described with reference to various embodiments, it is understood that the words, which have been used herein, are words of description and illustration, rather than words of limitation. Further, although the invention has been described herein with reference to particular means, materials, and embodiments, the invention is not intended to be limited to the particulars disclosed herein; rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. Those skilled in the art, having the benefit of the teachings of this specification, may effect numerous modifications thereto and changes may be made without departing from the scope and spirit of the invention in its aspects.
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