US20170167139A1 - Shallow undercut concrete anchor - Google Patents
Shallow undercut concrete anchor Download PDFInfo
- Publication number
- US20170167139A1 US20170167139A1 US15/371,645 US201615371645A US2017167139A1 US 20170167139 A1 US20170167139 A1 US 20170167139A1 US 201615371645 A US201615371645 A US 201615371645A US 2017167139 A1 US2017167139 A1 US 2017167139A1
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- anchor
- plug
- sleeve
- concrete
- legs
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- 239000004567 concrete Substances 0.000 title claims abstract description 98
- 230000007246 mechanism Effects 0.000 claims description 15
- 239000000463 material Substances 0.000 claims description 10
- 238000005553 drilling Methods 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 5
- 239000011178 precast concrete Substances 0.000 claims 5
- 238000009434 installation Methods 0.000 abstract description 19
- 238000006073 displacement reaction Methods 0.000 description 20
- 230000007704 transition Effects 0.000 description 5
- 238000010276 construction Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 238000009428 plumbing Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000004873 anchoring Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000002601 radiography Methods 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/08—Members specially adapted to be used in prestressed constructions
- E04C5/12—Anchoring devices
- E04C5/125—Anchoring devices the tensile members are profiled to ensure the anchorage, e.g. when provided with screw-thread, bulges, corrugations
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/38—Connections for building structures in general
- E04B1/48—Dowels, i.e. members adapted to penetrate the surfaces of two parts and to take the shear stresses
- E04B1/483—Shear dowels to be embedded in concrete
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/62—Insulation or other protection; Elements or use of specified material therefor
- E04B1/92—Protection against other undesired influences or dangers
- E04B1/98—Protection against other undesired influences or dangers against vibrations or shocks; against mechanical destruction, e.g. by air-raids
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/08—Members specially adapted to be used in prestressed constructions
- E04C5/12—Anchoring devices
- E04C5/122—Anchoring devices the tensile members are anchored by wedge-action
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
- E04G21/12—Mounting of reinforcing inserts; Prestressing
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/02—Structures consisting primarily of load-supporting, block-shaped, or slab-shaped elements
- E04B1/04—Structures consisting primarily of load-supporting, block-shaped, or slab-shaped elements the elements consisting of concrete, e.g. reinforced concrete, or other stone-like material
- E04B1/06—Structures consisting primarily of load-supporting, block-shaped, or slab-shaped elements the elements consisting of concrete, e.g. reinforced concrete, or other stone-like material the elements being prestressed
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
- E04C5/06—Reinforcing elements of metal, e.g. with non-structural coatings of high bending resistance, i.e. of essentially three-dimensional extent, e.g. lattice girders
- E04C5/0645—Shear reinforcements, e.g. shearheads for floor slabs
Definitions
- Post-tensioned (PT) slabs are typically flat slabs,band beam slabs or ribbed slabs.
- PT slabs offer the thinnest slab type, as the tensile stress to which the slab is exposed is limited by a compressive wire system. Longer spans can be achieved due to pre-stress, which can be used to counteract deflections.
- the slabs are pre-stressed by cables/wires that pass through the slabs.
- PT slabs are becoming more widely used for a number of reasons. Slabs can be thinner which will usually result in cost savings at least as a result of using less cement. In addition, less material necessarily means that the slabs are more environmentally friendly. Thinner lighter slabs lend to faster and easier construction/erection processes. Furthermore, PT slab concrete structures can usually bear load sooner than other conventional load bearing structures if not immediate. In fact, PT slabs are already the most common type of reinforcing floors (e.g., in high-rise construction and parking garages).
- FIG. 1 shows a PT slab having wire passing through it which wires are secured and tensioned at outer ends of the slab.
- the anchors support various systems such as plumbing or electrical equipment.
- an anchor may be secured in a PT slab which forms the ceiling in a building (e.g., a parking deck) so that a threaded rod can be supported from the anchor which threaded rod in turn supports piping for the building's sprinkler system.
- anchors may be positioned before the concrete is poured and thereby are cast in place.
- Post cast anchors are available in the industry that require drilling into the set concrete, inserting an anchor, and expanding the anchor to grip and secure itself in the hole.
- wire can be located as close as 1 or 2 inches from the slab concrete surface. Therefore, the location of and depth to which holes can be drilled for insertion of post cast anchors is limited.
- the present invention discloses a shallow undercut concrete anchor capable of resisting large loads while requiring a 3 ⁇ 4′′ embedment depth of less.
- an anchor system for securing an object (e.g. a pipe system) to a structure (e.g., a parking deck or slab of a high rise or other building).
- the system includes a concrete structure including a cylindrical opening in the concrete surface thereof.
- the concrete cylindrical opening can include an open end and a closed end.
- the system also uses an anchor which includes a sleeve and a plug.
- the sleeve includes at least two legs extending toward a first end of the sleeve and the sleeve also includes a second end.
- the sleeve further including a cylindrical through opening from the first end to the second end.
- the plug includes a first end and a second end and the plug also includes an increasing diameter portion disposed toward a first end of the plug. Furthermore, the plug including a locking opening. The second end of the plug is received in the cylindrical through opening until the increasing diameter portion engages the legs. The locking opening of the plug is accessible through the cylindrical through opening at the second end of the sleeve.
- the concrete cylindrical opening includes a cylindrical wall having a radius and a depth of approximately 3 ⁇ 4′′ or less. The anchor, via the first ends of the sleeve and plug respectively is received in the concrete cylindrical opening to approximately the depth.
- legs of the sleeve After installation, legs of the sleeve extend radially outward past the wall and the increasing diameter portion prevents inward movement of the legs to lock the sleeve and the plug in turn in the concrete cylindrical opening. Furthermore, dynamic loading on the plug (e.g., via a threaded rod) when the anchor is in use generates a dynamic radially outward force on the legs to secure the anchor in the concrete hole.
- FIG. 1 shows an embodiment of the general concept f the type of slab in which the present invention anchor can be installed.
- FIG. 2 shows a cross-sectional view of an embodiment of a conventional anchor for use in the slab of FIG. 1 .
- FIG. 3 shows a bottom perspective view of an embodiment of the anchor of the present invention.
- FIG. 4 shows a cross-sectional view of the preset anchor of FIG. 3 .
- FIG. 5A shows a perspective view of an embodiment of a sleeve of the anchor of FIG. 3 .
- FIG. 5B shows a front view of the anchor of FIG. 3 .
- FIG. 5C shows a cross sectional view of the sleeve of the anchor of FIG. 3 .
- FIG. 5D shows an enlarged cross sectional view of a portion of the sleeve of the anchor of FIG. 3 .
- FIG. 6A shows a perspective view of the plug of the anchor of FIG. 3 .
- FIG. 6B shows a side view of the plug of the anchor of FIG. 3 .
- FIG. 6C shows a cross-sectional view of the plug of the anchor of FIG. 3 .
- FIG. 7A shows a graph of load vs. displacement of the anchor of FIG. 2 .
- FIG. 7B shows a graph of another load vs. displacement of the anchor of FIG. 2 .
- FIG. 7C shows yet another graph of load vs. displacement of the anchor of FIG. 2 .
- FIG. 8A shows an exploded drilling and setting system of the anchor of FIG. 3 .
- FIG. 8B shows an assembled drilling and setting system of the anchor of FIG. 3 .
- FIG. 8C shows a side perspective view of the anchor of FIG. 3 in the post set configuration.
- FIG. 8D shows a cross-sectional view of the anchor of FIG. 3 in the post set configuration.
- FIG. 8E shows a bottom view of the anchor of FIG. 3 set in a portion of concrete that is broken out of a concrete surface to reveal a bottom portion of the set anchor, the failed surface of the concrete, and the concrete hole.
- FIG. 9 shows a graph of load vs. embedment depth in un-cracked concrete for the anchor of FIG. 3 .
- FIG. 10 shows a graph of load vs. embedment depth in cracked concrete for the anchor of FIG. 3 .
- FIG. 11A shows a table of values from which to determine reliability of the anchor of FIG. 3 under various installation conditions.
- FIG. 11B shows a table of values from which to determine reliability of the anchor of FIG. 3 under various installation conditions.
- FIG. 12 .A shows a graph of load vs. displacement of the anchor of FIG. 3 .
- FIG. 12B shows a graph of another load vs. displacement of the anchor of FIG. 3 .
- FIG. 13A shows a graph of displacement vs. cycles for a constant 120 lb load of the anchor of FIG. 3 .
- FIG. 13B shows a graph of load vs. displacement for an oversized hole using the anchor of FIG. 3 .
- FIG. 1 shows a post stressed concrete slab unit 10 .
- Slab unit 10 includes a volume (e.g., a rectangular volume) of poured and cured concrete 20 and a plurality of tension wires 30 passing through the concrete volume 20 .
- An individual wire 40 may be disposed at different depths in the direction of thickness of the slab based on loads expected to be experienced at particular areas of the slab when installed.
- Wires anchors 50 are positioned at outer surfaces of concrete 20 and tension of wires 30 may be adjusted there. With respect to the top and bottom outer surfaces of the concrete slab 20 , wire 40 may be positioned within 1 or 2 inches of the outer surfaces of the concrete.
- Some post cast anchors are used in PT slabs today. For example mini drop-in anchors with the following characteristics are used.
- FIG. 2 shows a cross section of the prior art mini drop-in anchor design. At a relatively low load the friction mechanism fails with the anchor being pulled out of the concrete hole.
- FIGS. 7A-7C illustrate some experimental results that show pull out failures of mini drip-in anchors at specific loads in un-cracked concrete.
- the graph in FIG. 7A plots load in terms of displacement (i.e., movement of the anchor out of the hole). The graph clearly shows steady movement of the anchor out of the hole as load in the desired load range increases.
- FIGS. 7B and 7C show graphed results of load in terms of displacement for a desired load when mini drop-in anchors are set in cracked concrete.
- FIGS. 7B and 7C clearly show that the anchors reach an unacceptable displacement during the desired load range and then completely fail. There is therefore a need to develop an anchor with an embedment depth of 3 ⁇ 4′′ or less that can consistently bear larger loads.
- FIG. 3 shows a perspective view of the shallow undercut anchor 100 of the present invention in its assembled, but preset configuration.
- a plug 300 is received in a sleeve 200 .
- FIG. 4 shows a cross-section of the plug and sleeve anchor of FIG. 3 .
- FIG. 5A shows a perspective view of sleeve 200 .
- Sleeve 200 is of a generally cylindrical form having an inner cylindrical surface 202 and an outer generally cylindrical surface 204 both of which define a sleeve wall 206 between.
- Inner cylindrical surface 202 includes a chamfer at its upper and lower ends for ease of insertion of plug 300 and threaded rods (described in further detail below).
- Sleeve 200 also includes an upper portion 210 and a lower portion 240 .
- a recessed waistband 260 At an interface between upper portion 210 and lower portion 240 is a recessed waistband 260 in wall 206 .
- Lower portion 240 includes a plurality of legs 250 A-D that extend downward from recessed waistband 260 . Between each pair of adjacent legs 250 is a gap 254 . (lap 254 extends from lower portion 240 to upper portion 210 .
- gap 256 extends from a lowermost end of the legs 250 upward through recessed waistband 266 and terminating at an annular stress relief opening 256 .
- Legs 250 of lower portion 240 can be said to include an upper portion 268 connected to a lower portion 272 .
- Lower portion 272 includes a converging edge 274 which engages the concrete hole wall during installation. The shape of the converging edge (about 90°) ensures that the pressure exerted on the concrete hole wall will be large to encourage cutting into the concrete.
- the outer generally cylindrical surface 204 at lower portion 240 includes a V-shaped recess 264 .
- V-shaped recess 264 extends between recessed waistband 260 and a lower terminal end 273 of legs 250 .
- V-shaped recess 264 extends radially inward so that a mouth of the V-shape opens radially outward creating a smaller wall radius at the point/apex of the V and defining a thinner wall section at the point of the V.
- the wall section being thinner at the point/apex of the V since generally inner cylindrical surface 202 maintains a constant radius through sleeve 200 .
- the two legs of the V forming recess 264 define outer wall surface portions 269 , 271 that are disposed approximately 144° apart.
- FIG. 6A shows a perspective view of plug 300 of anchor 100 .
- Plug 100 is made of steel or similar strength metals or materials.
- FIGS. 6B and 6C show that plug 300 includes a generally cylindrical upper portion 310 , a generally cylindrical lower portion 355 and an increasing diameter portion 350 connecting the lower portion 355 to the upper portion 310 .
- the increasing or tapered radius portion includes a first radius and a second increased radius and upper portion 310 connects to increasing diameter portion 350 at the first diameter.
- lower portion 355 connects to increased diameter portion 350 at the second increased diameter.
- Upper portion 310 includes an outer surface 312 and an interior opening 320 .
- Opening 320 includes an inner wall surface 322 which is fitted with a locking mechanism such as a female threaded (e.g., for receiving a male threaded rod). Opening 322 is further defined by a cone shaped volume or opening 323 in a bottom of opening 322 . Outer surface 312 further includes a boss or projection 360 which engages with a shaped recess of sleeve 200 to secure plug 300 to sleeve 200 and keep the two parts together as an anchor until anchor 100 is to be installed,
- a locking mechanism such as a female threaded (e.g., for receiving a male threaded rod). Opening 322 is further defined by a cone shaped volume or opening 323 in a bottom of opening 322 .
- Outer surface 312 further includes a boss or projection 360 which engages with a shaped recess of sleeve 200 to secure plug 300 to sleeve 200 and keep the two parts together as an anchor until anchor 100 is to be installed,
- FIG. 7A shows a graph of load vs. displacement of the prior art anchor of FIG. 2 in cracked 2,500 psi concrete.
- the various trials i.e., t 1 -t 3
- load i.e. a pulling out load
- FIG. 7B and 7C show graphs of load vs. displacement of the prior art anchor of FIG. 2 .
- FIG. 8A shows an installation mechanism 800 with which anchor 100 of the present invention can be installed.
- installation mechanism 800 includes a drill bit mechanism 820 and an impact installation tool 840 .
- Drill bit mechanism 820 includes a chuck receiving portion 822 for being received in a power tool such as a power hammer or hammer drill.
- Drill bit mechanism 820 also includes a bit 824 for drilling a. suitably sized hole in concrete (e.g., a post tensioned slab).
- a flange 826 is also provided on drill bit mechanism 820 with a surface 828 for controlling a depth to which bit 824 enters the concrete and gauging the angle in which the hole is being drilled.
- Impact installation tool 840 includes a receptacle 842 for receiving bit 824 and includes a guide 844 .
- Impact installation tool 840 also includes a shoulder 846 for limiting the axial distance guide 844 is inserted into upper portion 210 anchor 100 .
- FIG. 8B after a hole is drilled in the concrete using drill bit mechanism 820 , impact installation tool 840 is place over bit 824 until impact installation tool 840 engages surface 828 .
- anchor 100 is placed over guide 844 with guide 844 being received in opening 320 of sleeve 200 until a topmost portion 850 of sleeve 200 engages shoulder 846 .
- FIG. 8C shows a side view of an anchor 100 in the installed configuration
- FIG. 8D shows a cross-sectional view of anchor 100 of the present invention in the installed configuration.
- FIG. 8E shows a concrete portion broken out of a concrete slab to reveal a bottom view of a set anchor 100 .
- FIG. 8E clearly shows that after setting, edge 274 is lodged in the concrete hole 900 radially outward past the concrete hole wall.
- edge 274 This extension of edge 274 past a radial limit of hole 900 and into the concrete prevents or resists radial movement of anchor 100 over and above the simple friction resistance methods of the prior art. Furthermore, flexing back of legs 250 and thus edge 274 as an anchor pulling out load is applied is resisted or prevented by increasing diameter portion 350 and transition portion 352 .
- increasing diameter portion 350 not only blocks or prevents radially inward collapsing when loading, but any further axial pull out force applied to increasing diameter portion 350 translates into a further radially outward force exerted on surface 276 of legs 250 .
- increasing diameter portion 350 creates a dynamic continuous radially outward force on legs 250 rather than just a passive prevention of leg collapse because increasing diameter portion 350 of plug 300 is free to move axially relative to legs 250 of wedged sleeve 200 .
- outer wall of the second threaded end of plug 300 may have a slightly smaller radius than the adjacent surrounding sleeve inner wall as shown in FIG. 4 .
- the smaller plug wall radius can ensure that the walls can freely move past each other telescopically and minimize the friction caused between the inner and outer walls. Therefore, after installation when threads of plug 300 are loaded in the pull out direction, that load is transferred minimally (if at all) into friction, but mostly through the increased diameter portion 350 which in turn radially outwardly loads legs 250 .
- the final installation configuration of anchor 100 has terminal end 273 of legs 250 extending down proximate or to lower end 355 of plug 300 . Because lower end 355 of plug 300 is cylindrical (not tapered like 350 ), when leg 250 gets jammed or forced between hole 900 and lower end 340 , surface 276 of lower portion 272 gets force radially over and against a diameter transition 352 . Lower portion 272 also gets forced inward by wall 900 . Specifically, lower portion 272 if forced or bent inward toward lower end 355 . Therefore, wall 900 pushes radially inward on an end of leg 250 (e.g., at 274 ) as diameter transition 352 pushes radially outward.
- the present invention anchor 100 therefore provides at least two mechanisms (i.e., transferring axial plug load into outward radial three on legs and flexing of legs over transition 352 ) for dynamically resisting pull out displacement from hole 900 . Furthermore, in that final installation configuration, at least a portion of surface 269 engages wall or hole 900 while surface 271 and edge 274 engage wall 900 and extend into wall 900 .
- diameter transition 352 is positioned to engage surface 276 such that a final position of wall 269 may be generally vertical. In this configuration, inner surfaces of portions 268 and 272 rotates to engage and become supported by an angled increasing diameter portion 350 and/or a lower portion 355 .
- FIG. 9 shows a graph of load vs. embedment depth in un-cracked concrete for the anchor of FIG. 3 .
- FIG. 10 shows a graph of load vs. embedment depth in cracked concrete for the anchor of FIG. 3 .
- Both of FIGS. 9 and 10 show lines defined by applicable building code equations where the present invention anchor 100 always fails at loads acceptably above code minimums for both high and low strength concretes.
- the present invention anchor is capable of developing a tensile capacity of about 455 lbs in a cracked-concrete condition, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi; is capable of developing a shear capacity of about 985 lbs in a cracked-concrete condition, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi; is capable of developing a tensile capacity of about 410 lbs in a seismic condition, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi; is capable of developing a shear capacity of about 895 lbs in a seismic condition according to national code, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi.
- National codes can be found in ICC Evaluation Service's ICC-ES Report (ESR-3912) Division: 03 00 00—Concrete Section:03
- FIGS. 11A and 11B show the results of a series of reliability tests for various concrete strengths, cracked and un-cracked concretes, and for embedment depths. The data shows acceptable values in all cases.
- FIGS. 12A and 12B shows a graph of load vs. displacement of the present invention anchor 100 in low and high strength cracked concrete.
- the various trials i.e.,lines of the graph
- the steeper curve shows the desirability of the present invention anchor 100 under the stated test conditions and which could not be achieved with the prior art anchor solution.
- FIG. 13A shows a graph of displacement vs.
- FIG. 13B shows a graph of load vs. displacement for an oversized hole using the anchor of FIG. 3 .
- the characteristic low slope behavior of the various trial graphs illustrate the hesitation of the present invention anchor 100 to pull out or to displacement.
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Abstract
A concrete anchor capable of resisting large loads while requiring minimal embedment depth. The system includes a concrete structure including a cylindrical opening in the concrete surface thereof. The system also uses an anchor which includes a sleeve and a plug. The sleeve includes at least two legs extending toward a first end of the sleeve. The plug includes an increasing diameter portion disposed toward a first end of the plug. The plug includes a locking opening. After installation, legs of the sleeve extend radially outward past the wall and the increasing diameter portion prevents inward movement of the legs to lock the sleeve and the plug in turn in the concrete cylindrical opening. Furthermore, dynamic loading on the plug via the locking opening when the anchor is in use generates a dynamic radially outward force on the legs to secure the anchor in the concrete hole.
Description
- The following application hereby incorporates by reference and derives priority from U.S. Provisional Application No. 62/265,212 filed on Dec. 9, 2015, now pending.
- Post-tensioned (PT) slabs are typically flat slabs,band beam slabs or ribbed slabs. PT slabs offer the thinnest slab type, as the tensile stress to which the slab is exposed is limited by a compressive wire system. Longer spans can be achieved due to pre-stress, which can be used to counteract deflections. The slabs are pre-stressed by cables/wires that pass through the slabs.
- PT slabs are becoming more widely used for a number of reasons. Slabs can be thinner which will usually result in cost savings at least as a result of using less cement. In addition, less material necessarily means that the slabs are more environmentally friendly. Thinner lighter slabs lend to faster and easier construction/erection processes. Furthermore, PT slab concrete structures can usually bear load sooner than other conventional load bearing structures if not immediate. In fact, PT slabs are already the most common type of reinforcing floors (e.g., in high-rise construction and parking garages).
-
FIG. 1 shows a PT slab having wire passing through it which wires are secured and tensioned at outer ends of the slab. When individual slab units are combined in the construction of a building structure, that structure will sometimes require anchors attached thereto. The anchors support various systems such as plumbing or electrical equipment. For example, an anchor may be secured in a PT slab which forms the ceiling in a building (e.g., a parking deck) so that a threaded rod can be supported from the anchor which threaded rod in turn supports piping for the building's sprinkler system. - Most PT slabs have three options for anchoring. First, anchors may be positioned before the concrete is poured and thereby are cast in place. Post cast anchors are available in the industry that require drilling into the set concrete, inserting an anchor, and expanding the anchor to grip and secure itself in the hole. Because PT slabs are relatively flat/thin, the cables/wires that pass through the concrete are generally close to the surface of the concrete. Specifically, wire can be located as close as 1 or 2 inches from the slab concrete surface. Therefore, the location of and depth to which holes can be drilled for insertion of post cast anchors is limited. In fact, to ensure that drilled holes are not improperly installed, builders presently use slow and expensive radiography equipment to locate cable/wire within the cast PT slab. In any case (by some building codes) holes for receiving post cast anchors cannot be drilled to greater than a ¾″ depth.
- As mentioned above, many of the anchors that will be secured in a concrete slab can be preset anchors. On the other hand, for various reasons it may not be possible or desirable to utilize preset anchors. Therefore, after the slab has been cast there will frequently be a need to install a support mechanism for an auxiliary building system (e.g., plumbing, electrical, etc.). There is therefore a need to develop a system which utilizes a post cast concrete anchor for securing within a drilled hole that is ¾″ or less in depth. There is also a need to develop such an anchor that can bear a minimum load under various standard test conditions.
- The present invention discloses a shallow undercut concrete anchor capable of resisting large loads while requiring a ¾″ embedment depth of less. Specifically, the present invention discloses an anchor system for securing an object (e.g. a pipe system) to a structure (e.g., a parking deck or slab of a high rise or other building). The system includes a concrete structure including a cylindrical opening in the concrete surface thereof. The concrete cylindrical opening can include an open end and a closed end. The system also uses an anchor which includes a sleeve and a plug. The sleeve includes at least two legs extending toward a first end of the sleeve and the sleeve also includes a second end. The sleeve further including a cylindrical through opening from the first end to the second end. The plug includes a first end and a second end and the plug also includes an increasing diameter portion disposed toward a first end of the plug. Furthermore, the plug including a locking opening. The second end of the plug is received in the cylindrical through opening until the increasing diameter portion engages the legs. The locking opening of the plug is accessible through the cylindrical through opening at the second end of the sleeve. The concrete cylindrical opening includes a cylindrical wall having a radius and a depth of approximately ¾″ or less. The anchor, via the first ends of the sleeve and plug respectively is received in the concrete cylindrical opening to approximately the depth. After installation, legs of the sleeve extend radially outward past the wall and the increasing diameter portion prevents inward movement of the legs to lock the sleeve and the plug in turn in the concrete cylindrical opening. Furthermore, dynamic loading on the plug (e.g., via a threaded rod) when the anchor is in use generates a dynamic radially outward force on the legs to secure the anchor in the concrete hole.
-
FIG. 1 shows an embodiment of the general concept f the type of slab in which the present invention anchor can be installed. -
FIG. 2 shows a cross-sectional view of an embodiment of a conventional anchor for use in the slab ofFIG. 1 . -
FIG. 3 shows a bottom perspective view of an embodiment of the anchor of the present invention. -
FIG. 4 shows a cross-sectional view of the preset anchor ofFIG. 3 . -
FIG. 5A shows a perspective view of an embodiment of a sleeve of the anchor ofFIG. 3 . -
FIG. 5B shows a front view of the anchor ofFIG. 3 . -
FIG. 5C shows a cross sectional view of the sleeve of the anchor ofFIG. 3 . -
FIG. 5D shows an enlarged cross sectional view of a portion of the sleeve of the anchor ofFIG. 3 . -
FIG. 6A shows a perspective view of the plug of the anchor ofFIG. 3 . -
FIG. 6B shows a side view of the plug of the anchor ofFIG. 3 . -
FIG. 6C shows a cross-sectional view of the plug of the anchor ofFIG. 3 . -
FIG. 7A shows a graph of load vs. displacement of the anchor ofFIG. 2 . -
FIG. 7B shows a graph of another load vs. displacement of the anchor ofFIG. 2 . -
FIG. 7C shows yet another graph of load vs. displacement of the anchor ofFIG. 2 . -
FIG. 8A shows an exploded drilling and setting system of the anchor ofFIG. 3 . -
FIG. 8B shows an assembled drilling and setting system of the anchor ofFIG. 3 . -
FIG. 8C shows a side perspective view of the anchor ofFIG. 3 in the post set configuration. -
FIG. 8D shows a cross-sectional view of the anchor ofFIG. 3 in the post set configuration. -
FIG. 8E shows a bottom view of the anchor ofFIG. 3 set in a portion of concrete that is broken out of a concrete surface to reveal a bottom portion of the set anchor, the failed surface of the concrete, and the concrete hole. -
FIG. 9 shows a graph of load vs. embedment depth in un-cracked concrete for the anchor ofFIG. 3 . -
FIG. 10 shows a graph of load vs. embedment depth in cracked concrete for the anchor ofFIG. 3 . -
FIG. 11A shows a table of values from which to determine reliability of the anchor ofFIG. 3 under various installation conditions. -
FIG. 11B shows a table of values from which to determine reliability of the anchor ofFIG. 3 under various installation conditions. -
FIG. 12 .A shows a graph of load vs. displacement of the anchor ofFIG. 3 . -
FIG. 12B shows a graph of another load vs. displacement of the anchor ofFIG. 3 . -
FIG. 13A shows a graph of displacement vs. cycles for a constant 120 lb load of the anchor ofFIG. 3 . -
FIG. 13B shows a graph of load vs. displacement for an oversized hole using the anchor ofFIG. 3 . -
FIG. 1 shows a post stressedconcrete slab unit 10.Slab unit 10 includes a volume (e.g., a rectangular volume) of poured and cured concrete 20 and a plurality oftension wires 30 passing through theconcrete volume 20. Anindividual wire 40 may be disposed at different depths in the direction of thickness of the slab based on loads expected to be experienced at particular areas of the slab when installed. Wires anchors 50 are positioned at outer surfaces ofconcrete 20 and tension ofwires 30 may be adjusted there. With respect to the top and bottom outer surfaces of theconcrete slab 20,wire 40 may be positioned within 1 or 2 inches of the outer surfaces of the concrete. - Some post cast anchors are used in PT slabs today. For example mini drop-in anchors with the following characteristics are used.
-
Thread Diameter [in.] ¼″ ⅜″ ½″ Drill Bit Diameter [in.] ⅜ ½ ⅝ Embedment depth [in.] ⅝ ¾ 1 (16 mm) (25.4 mm) Threaded Depth [in.] ⅜ 13/32 ⅝ Installation Torque [ft-lbs] 3 5 10 - These mini drop-in anchors utilize a friction mechanism to resist pull out failure.
FIG. 2 shows a cross section of the prior art mini drop-in anchor design. At a relatively low load the friction mechanism fails with the anchor being pulled out of the concrete hole.FIGS. 7A-7C illustrate some experimental results that show pull out failures of mini drip-in anchors at specific loads in un-cracked concrete. The graph inFIG. 7A plots load in terms of displacement (i.e., movement of the anchor out of the hole). The graph clearly shows steady movement of the anchor out of the hole as load in the desired load range increases. Similarly,FIGS. 7B and 7C show graphed results of load in terms of displacement for a desired load when mini drop-in anchors are set in cracked concrete.FIGS. 7B and 7C clearly show that the anchors reach an unacceptable displacement during the desired load range and then completely fail. There is therefore a need to develop an anchor with an embedment depth of ¾″ or less that can consistently bear larger loads. - The structure of the present invention will now be described with respect to
FIGS. 3-6 .FIG. 3 shows a perspective view of the shallow undercutanchor 100 of the present invention in its assembled, but preset configuration. In this assembled configuration aplug 300 is received in asleeve 200.FIG. 4 shows a cross-section of the plug and sleeve anchor ofFIG. 3 .FIG. 5A shows a perspective view ofsleeve 200.Sleeve 200 is of a generally cylindrical form having an innercylindrical surface 202 and an outer generallycylindrical surface 204 both of which define asleeve wall 206 between. Innercylindrical surface 202 includes a chamfer at its upper and lower ends for ease of insertion ofplug 300 and threaded rods (described in further detail below).Sleeve 200 also includes anupper portion 210 and alower portion 240. At an interface betweenupper portion 210 andlower portion 240 is a recessedwaistband 260 inwall 206.Lower portion 240 includes a plurality oflegs 250A-D that extend downward from recessedwaistband 260. Between each pair ofadjacent legs 250 is agap 254. (lap 254 extends fromlower portion 240 toupper portion 210. Specifically,gap 256 extends from a lowermost end of thelegs 250 upward through recessed waistband 266 and terminating at an annularstress relief opening 256. -
Legs 250 oflower portion 240 can be said to include anupper portion 268 connected to alower portion 272.Lower portion 272 includes a convergingedge 274 which engages the concrete hole wall during installation. The shape of the converging edge (about 90°) ensures that the pressure exerted on the concrete hole wall will be large to encourage cutting into the concrete. - The outer generally
cylindrical surface 204 atlower portion 240 includes a V-shapedrecess 264. V-shapedrecess 264 extends between recessedwaistband 260 and a lowerterminal end 273 oflegs 250. Furthermore, V-shapedrecess 264 extends radially inward so that a mouth of the V-shape opens radially outward creating a smaller wall radius at the point/apex of the V and defining a thinner wall section at the point of the V. The wall section being thinner at the point/apex of the V since generally innercylindrical surface 202 maintains a constant radius throughsleeve 200. The two legs of theV forming recess 264 define outerwall surface portions - Plug 300 will now be described with reference
FIGS. 6A-6C .FIG. 6A shows a perspective view ofplug 300 ofanchor 100.Plug 100 is made of steel or similar strength metals or materials.FIGS. 6B and 6C show thatplug 300 includes a generally cylindricalupper portion 310, a generally cylindricallower portion 355 and an increasingdiameter portion 350 connecting thelower portion 355 to theupper portion 310. The increasing or tapered radius portion includes a first radius and a second increased radius andupper portion 310 connects to increasingdiameter portion 350 at the first diameter. Similarly,lower portion 355 connects to increaseddiameter portion 350 at the second increased diameter.Upper portion 310 includes anouter surface 312 and aninterior opening 320.Opening 320 includes aninner wall surface 322 which is fitted with a locking mechanism such as a female threaded (e.g., for receiving a male threaded rod).Opening 322 is further defined by a cone shaped volume or opening 323 in a bottom ofopening 322.Outer surface 312 further includes a boss orprojection 360 which engages with a shaped recess ofsleeve 200 to secureplug 300 tosleeve 200 and keep the two parts together as an anchor untilanchor 100 is to be installed, -
FIG. 7A shows a graph of load vs. displacement of the prior art anchor ofFIG. 2 in cracked 2,500 psi concrete. The various trials (i.e., t1-t3) show a steady undesirable displacement of the anchor out of the sleeve as load (i.e. a pulling out load) is applied. A steeper curve would be more desirable but could not be achieved with the prior art anchor solution. Similarly,FIG. 7B and 7C show graphs of load vs. displacement of the prior art anchor ofFIG. 2 . -
FIG. 8A shows aninstallation mechanism 800 with which anchor 100 of the present invention can be installed. Specifically,installation mechanism 800 includes adrill bit mechanism 820 and animpact installation tool 840.Drill bit mechanism 820 includes achuck receiving portion 822 for being received in a power tool such as a power hammer or hammer drill.Drill bit mechanism 820 also includes abit 824 for drilling a. suitably sized hole in concrete (e.g., a post tensioned slab). Aflange 826 is also provided ondrill bit mechanism 820 with asurface 828 for controlling a depth to whichbit 824 enters the concrete and gauging the angle in which the hole is being drilled. -
Impact installation tool 840 includes areceptacle 842 for receivingbit 824 and includes aguide 844.Impact installation tool 840 also includes ashoulder 846 for limiting theaxial distance guide 844 is inserted intoupper portion 210anchor 100. As shown inFIG. 8B , after a hole is drilled in the concrete usingdrill bit mechanism 820,impact installation tool 840 is place overbit 824 untilimpact installation tool 840 engagessurface 828. Similarly,anchor 100 is placed overguide 844 withguide 844 being received in opening 320 ofsleeve 200 until atopmost portion 850 ofsleeve 200 engagesshoulder 846. - Installation of
anchor 100 can then be completed when the powered hammer/hammer drill mechanism is driven so thatshoulder 846 drivessleeve 200 overplug 300.FIG. 8C shows a side view of ananchor 100 in the installed configuration andFIG. 8D shows a cross-sectional view ofanchor 100 of the present invention in the installed configuration. Assleeve 200 is forced overplug 100,legs 250 each ride up on increasingradius portion 350 and forcing alower portion 240 ofsleeve 200 outward radially. Aslegs 250 are forced outward, bending stresses atwaistband 260 increases and since the sleeve wall diameter is reduced atwaistband 260, each leg begins to bend outward atwaistband 260. The result is a sort of rotation oflower portion 240 of the sleeve wherelower portion 240 is supported in the new set rotated position byplug 300's increasingdiameter portion 350. - Also as
legs 250 are forced outward,edge 274 is forced into the surround concrete wall of the concrete hole into which the anchor is to be set. The forcing results from impact tosleeve 200 which urginglegs 250 over increasingdiameter portion 350 and outward into the concrete hole wall forcibly displacing a portion of the concrete to extend radially past thehole wall 900.FIG. 8E shows a concrete portion broken out of a concrete slab to reveal a bottom view of aset anchor 100.FIG. 8E clearly shows that after setting,edge 274 is lodged in theconcrete hole 900 radially outward past the concrete hole wall. This extension ofedge 274 past a radial limit ofhole 900 and into the concrete prevents or resists radial movement ofanchor 100 over and above the simple friction resistance methods of the prior art. Furthermore, flexing back oflegs 250 and thus edge 274 as an anchor pulling out load is applied is resisted or prevented by increasingdiameter portion 350 andtransition portion 352. - Moreover, because the pulling out load is applied to plug 300 via locking
member 322, increasingdiameter portion 350 not only blocks or prevents radially inward collapsing when loading, but any further axial pull out force applied to increasingdiameter portion 350 translates into a further radially outward force exerted onsurface 276 oflegs 250. In other words, increasingdiameter portion 350 creates a dynamic continuous radially outward force onlegs 250 rather than just a passive prevention of leg collapse because increasingdiameter portion 350 ofplug 300 is free to move axially relative tolegs 250 of wedgedsleeve 200. As a result, under the condition of a crack in the wall ofconcrete hole 900 which might increase the hole size, any pulling out load applied to plug 300 as the hole gets larger also will tend to further spreadlegs 250 apart radially to compensate as the hole gets larger. Furthermore, outer wall of the second threaded end ofplug 300 may have a slightly smaller radius than the adjacent surrounding sleeve inner wall as shown inFIG. 4 . The smaller plug wall radius can ensure that the walls can freely move past each other telescopically and minimize the friction caused between the inner and outer walls. Therefore, after installation when threads ofplug 300 are loaded in the pull out direction, that load is transferred minimally (if at all) into friction, but mostly through the increaseddiameter portion 350 which in turn radially outwardly loadslegs 250. - The final installation configuration of
anchor 100 hasterminal end 273 oflegs 250 extending down proximate or tolower end 355 ofplug 300. Becauselower end 355 ofplug 300 is cylindrical (not tapered like 350), whenleg 250 gets jammed or forced betweenhole 900 andlower end 340,surface 276 oflower portion 272 gets force radially over and against adiameter transition 352.Lower portion 272 also gets forced inward bywall 900. Specifically,lower portion 272 if forced or bent inward towardlower end 355. Therefore,wall 900 pushes radially inward on an end of leg 250 (e.g., at 274) asdiameter transition 352 pushes radially outward. This creates an radially outward flexing of a lower end oflegs 250 which can be cantilevered relative to plug 300 to provide a dynamic or elastic outward biasing oflegs 250 againstwall 900 that may compensate for hole size variations do to cracking or other concrete failure over the course of an installation life. Thepresent invention anchor 100 therefore provides at least two mechanisms (i.e., transferring axial plug load into outward radial three on legs and flexing of legs over transition 352) for dynamically resisting pull out displacement fromhole 900. Furthermore, in that final installation configuration, at least a portion ofsurface 269 engages wall orhole 900 whilesurface 271 and edge 274 engagewall 900 and extend intowall 900. In one embodiment,diameter transition 352 is positioned to engagesurface 276 such that a final position ofwall 269 may be generally vertical. In this configuration, inner surfaces ofportions diameter portion 350 and/or alower portion 355. -
FIG. 9 shows a graph of load vs. embedment depth in un-cracked concrete for the anchor ofFIG. 3 .FIG. 10 shows a graph of load vs. embedment depth in cracked concrete for the anchor ofFIG. 3 . Both ofFIGS. 9 and 10 show lines defined by applicable building code equations where thepresent invention anchor 100 always fails at loads acceptably above code minimums for both high and low strength concretes. - According to national codes, the present invention anchor is capable of developing a tensile capacity of about 455 lbs in a cracked-concrete condition, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi; is capable of developing a shear capacity of about 985 lbs in a cracked-concrete condition, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi; is capable of developing a tensile capacity of about 410 lbs in a seismic condition, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi; is capable of developing a shear capacity of about 895 lbs in a seismic condition according to national code, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi. National codes can be found in ICC Evaluation Service's ICC-ES Report (ESR-3912) Division: 03 00 00—Concrete Section:03 16 00—Concrete Anchors which is incorporated herein by reference in its entirety.
-
FIGS. 11A and 11B show the results of a series of reliability tests for various concrete strengths, cracked and un-cracked concretes, and for embedment depths. The data shows acceptable values in all cases. In addition,FIGS. 12A and 12B shows a graph of load vs. displacement of thepresent invention anchor 100 in low and high strength cracked concrete. The various trials (i.e.,lines of the graph) show a steep desirable and limited displacement of the anchor out of the sleeve as load (i.e. a pulling out load) is applied. The steeper curve shows the desirability of thepresent invention anchor 100 under the stated test conditions and which could not be achieved with the prior art anchor solution. Similarly,FIG. 13A shows a graph of displacement vs. cycles for a constant 120 lb load of the anchor ofFIG. 3 . The characteristic low slope behavior of the various trial graphs illustrate the hesitation of thepresent invention anchor 100 to pull out or to displacement. In addition,FIG. 13B shows a graph of load vs. displacement for an oversized hole using the anchor ofFIG. 3 . Here again, the characteristic low slope behavior of the various trial graphs illustrate the hesitation of thepresent invention anchor 100 to pull out or to displacement.
Claims (23)
1. An anchor for securing an object to a precast concrete structure, the precast concrete structure including a cylindrical opening in a surface of the concrete structure and the precast concrete structure further including an elongated tension member passing through the precast concrete structure, the elongate tension member further including ends secured to the precast concrete structure, the anchor comprising:
a sleeve and a plug, the sleeve and plug sharing a central longitudinal axis,
the sleeve including at least two legs extending toward a first end of the sleeve and the sleeve also including a second end opposite the first end, the sleeve further including a cylindrical through opening from the first end to the second end,
the plug including a first end for engaging the legs and a second end opposite the first end, the plug received in the cylindrical through opening along the central longitudinal axis,
a tapered portion disposed on at least one of the plug and the legs, a locking portion located on at least one of the plug and the legs,
wherein when the plug and sleeve are forced telescopically relative to each other along the central longitudinal axis, the tapered portion forces the legs to expand radially outward, and
wherein the sleeve is ¾ inches or less in the longitudinal direction and the plug is ¾ inches or less in the longitudinal direction.
2. The anchor of claim 1 , wherein the locking portion is located on the plug and a pull out load applied to the locking portion initiates a radially outward force on the legs.
3. The anchor of claim 1 , wherein the concrete cylindrical opening includes a cylindrical wall having a radius and having a depth of approximately ¾ inches or less, the anchor via the first ends of the sleeve and plug being received in the concrete cylindrical opening to approximately the depth.
3. The anchor of claim 1 , wherein in a collapsed, installed configuration, the anchor has a dimension in the longitudinal direction of about ¾ inches or less.
4. The anchor of claim 1 , wherein a leg of the sleeve extends radially outward past at least a portion of the cylindrical wall and the tapered portion preventing inward movement of the legs to lock the sleeve and the plug in turn in the concrete cylindrical opening.
5. The anchor of claim 1 , wherein the locking portion is a threaded opening.
6. The anchor of claim 2 , further including a threaded rod,
wherein the threaded rod includes a first end and a second end and the first end is couplable to the threaded opening, and
wherein a load applied to the threaded rod at the second end in an axial direction away from the concrete opening applies a radially force to the legs.
7. The anchor of claim 1 , wherein the concrete structure is in the form of a slab, and
wherein the slab includes a thickness, T in inches and the ratio of the thickness T to an anchor embedment depth, in inches, in the concrete cylindrical opening is greater than T.
8. The anchor of claim 1 , wherein the anchor is capable of developing a tensile capacity of about 455 lbs in a cracked-concrete condition according to national code, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi.
9. The anchor of claim 1 , wherein the anchor is capable of developing a shear capacity of about 985 lbs in a cracked-concrete condition according to national code, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi.
10. The anchor of claim 1 , wherein the anchor is capable of developing a tensile capacity of about 410 lbs in a seismic condition according to national code, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi.
11. The anchor of claim 1 , wherein the anchor is capable of developing a shear capacity of about 895 lbs in a seismic condition according to national code, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi.
12. A method of installing an anchor in a post tensioned concrete structure comprising the steps of:
providing a post tensioned concrete structure including a concrete surface,
drilling a cylindrical opening in the concrete surface, the opening having a depth of 0.75 inches or less,
the concrete cylindrical opening further including an open end and a closed end and a cylindrical wall having a radius, and
providing an anchor including a sleeve and a plug,
the sleeve including at least two legs extending toward a first end of the sleeve and the sleeve also including a second end opposite the first end, the sleeve further including a cylindrical through opening from the first end to the second end,
the plug including a first end for engaging the legs and a second end opposite the first end, the plug received in the cylindrical through opening,
a tapered portion disposed on at least one of the plug and the legs, a locking portion located on at least one of the plug and the legs,
inserting the first ends of the sleeve and plug into the concrete cylindrical opening at a depth from the surface of no more than 0.75 inches, and
forcing the plug and sleeve telescopically relative to each other so that the legs are forced radially outward, and so that the tapered portion prevents inward movement of the legs to lock the sleeve and the plug to the wall of the concrete cylindrical opening.
13. The method of claim 12 , wherein the locking portion is on the plug.
14. The method of claim 12 , where in the step of providing an anchor including a sleeve and a plug is the step of providing an anchor with a sleeve and a plug each having a longitudinal dimension of ¾ inches or less.
15. An anchor system for securing an object to a structure comprising in combination:
a concrete structure including a concrete cylindrical opening in a surface thereof, the concrete cylindrical opening including an open end and a closed end, and
a anchor including a sleeve and a plug,
the sleeve including at least two legs extending toward a first end of the sleeve and the sleeve also including a second end opposite the first end, the sleeve further including a cylindrical through opening from the first end to the second end,
the plug including a first end for engaging the legs and a second end opposite the first end, the plug received in the cylindrical through opening,
a tapered portion disposed on at least one of the plug and the legs, a locking portion located on at least one of the plug and the legs,
wherein when the plug and sleeve are forced telescopically relative to each other, the legs are forced radially outward as a result of the tapered portion.
16. The anchor system of claim 15 , wherein the concrete cylindrical opening includes a cylindrical wall having a radius and having a depth of approximately ¾″ or less, the anchor via the first ends of the sleeve and plug being received in the concrete cylindrical opening to approximately the depth.
17. The anchor system of claim 15 , wherein a leg of the sleeve extends radially outward past the wall and the tapered portion preventing inward movement of the legs to lock the sleeve and the plug in turn in the concrete cylindrical opening.
18. The anchor system of claim 15 , wherein the concrete structure is a post tensioned concrete structure.
19. The anchor system of claim 18 , wherein the post tensioned concrete structure includes a wire passing through the structure, tension in the wire being applied primarily at ends of the wire.
20. The anchor system of claim 19 , further including a mechanism for adjusting the tension of the wire.
21. The anchor of claim 15 , wherein the locking portion is located on the plug and a pull out load applied to the locking portion translates into a radially outward force on the legs.
22. The anchor of claim 15 , wherein in a collapsed, installed configuration, the anchor has a dimension in the longitudinal direction of about ¾ inches or less.
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/371,645 US20170167139A1 (en) | 2015-12-09 | 2016-12-07 | Shallow undercut concrete anchor |
AU2016365744A AU2016365744B2 (en) | 2015-12-09 | 2016-12-08 | Shallow undercut concrete anchor |
EP16873814.4A EP3387271A4 (en) | 2015-12-09 | 2016-12-08 | Shallow undercut concrete anchor |
CA3007313A CA3007313A1 (en) | 2015-12-09 | 2016-12-08 | Shallow undercut concrete anchor |
PCT/US2016/065508 WO2017100392A1 (en) | 2015-12-09 | 2016-12-08 | Shallow undercut concrete anchor |
AU2021203281A AU2021203281B2 (en) | 2015-12-09 | 2021-05-21 | Shallow undercut concrete anchor |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US201562265212P | 2015-12-09 | 2015-12-09 | |
US15/371,645 US20170167139A1 (en) | 2015-12-09 | 2016-12-07 | Shallow undercut concrete anchor |
Publications (1)
Publication Number | Publication Date |
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US20170167139A1 true US20170167139A1 (en) | 2017-06-15 |
Family
ID=59014208
Family Applications (1)
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US15/371,645 Abandoned US20170167139A1 (en) | 2015-12-09 | 2016-12-07 | Shallow undercut concrete anchor |
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US (1) | US20170167139A1 (en) |
EP (1) | EP3387271A4 (en) |
AU (2) | AU2016365744B2 (en) |
CA (1) | CA3007313A1 (en) |
WO (1) | WO2017100392A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
USD856787S1 (en) | 2017-09-27 | 2019-08-20 | Illinois Tool Works Inc. | Undercut anchor attachment barrel |
US10995487B2 (en) | 2017-09-27 | 2021-05-04 | Illinois Tool Works Inc. | Undercut anchor, undercut anchor manufacturing method, and anchoring method |
US11815115B2 (en) | 2018-05-03 | 2023-11-14 | Hilti Aktiengesellschaft | Expansion anchor with protected optical code |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110593141A (en) * | 2019-09-21 | 2019-12-20 | 北京凯新浩达工程技术有限公司 | Bridge prestress reinforcing structure and reinforcing method |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4442646A (en) * | 1980-10-28 | 1984-04-17 | Ponteggi Est S.P.A. | Device for anchoring tensioning elements |
MY115793A (en) * | 1995-02-17 | 2003-09-30 | Illinois Tool Works | Masonry anchor |
FR2817303B1 (en) * | 2000-11-29 | 2004-04-23 | Prospection & Inventions | EXPANDABLE SOCKET ANKLE WITH COMPRESSIBLE PORTION |
US8434980B2 (en) * | 2010-09-25 | 2013-05-07 | Yow Cheng Co., Ltd. | Expansible anchor assembly and its fastening adaptor |
-
2016
- 2016-12-07 US US15/371,645 patent/US20170167139A1/en not_active Abandoned
- 2016-12-08 WO PCT/US2016/065508 patent/WO2017100392A1/en active Application Filing
- 2016-12-08 EP EP16873814.4A patent/EP3387271A4/en active Pending
- 2016-12-08 CA CA3007313A patent/CA3007313A1/en active Pending
- 2016-12-08 AU AU2016365744A patent/AU2016365744B2/en active Active
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2021
- 2021-05-21 AU AU2021203281A patent/AU2021203281B2/en active Active
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
USD856787S1 (en) | 2017-09-27 | 2019-08-20 | Illinois Tool Works Inc. | Undercut anchor attachment barrel |
USD880997S1 (en) | 2017-09-27 | 2020-04-14 | Illinois Tool Works Inc. | Undercut anchor attachment barrel |
US10995487B2 (en) | 2017-09-27 | 2021-05-04 | Illinois Tool Works Inc. | Undercut anchor, undercut anchor manufacturing method, and anchoring method |
US11815115B2 (en) | 2018-05-03 | 2023-11-14 | Hilti Aktiengesellschaft | Expansion anchor with protected optical code |
Also Published As
Publication number | Publication date |
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CA3007313A1 (en) | 2017-06-15 |
AU2016365744B2 (en) | 2021-05-06 |
EP3387271A4 (en) | 2019-09-04 |
WO2017100392A1 (en) | 2017-06-15 |
AU2021203281B2 (en) | 2023-09-07 |
EP3387271A1 (en) | 2018-10-17 |
AU2021203281A1 (en) | 2021-06-17 |
AU2016365744A1 (en) | 2018-06-07 |
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