JP7495895B2 - Anchor device - Google Patents

Description

The present invention relates to an anchor device for fixing a fixed object, such as a steel structure, to a concrete structure used, for example, in a bridge.

In general, when fixing a fixed object such as a steel structure to a concrete structure such as a bridge pier or abutment, an anchor is embedded in the concrete structure and the fixed object is fixed to a base plate attached to the anchor.

The first conventional example of such an anchor is one in which an anchor hole is pre-formed in a concrete structure, an anchor bolt fastened to a base plate is inserted into the anchor hole, and the gap in the anchor hole is filled with mortar to embed the anchor bolt (see, for example, Patent Document 1).

As a second conventional example, an anchor bolt is embedded in a concrete structure before concrete is poured, and the anchor bolt is fastened to a base plate having holes for inserting the anchor bolt. In this case, the holes for inserting the anchor bolt are provided at positions corresponding to the multiple anchor bolts, and are formed with an inner diameter approximately equal to the outer diameter of the anchor bolt (see, for example, Patent Document 2).

In a third conventional example, similar to the second conventional example, an anchor bolt is embedded in a concrete structure before concrete is poured, and the anchor bolt is fastened to a base plate having a hole for inserting the anchor bolt. In this case, the hole for inserting the anchor bolt is formed with an inner diameter larger than the outer diameter of the anchor bolt to absorb misalignment, and the anchor bolt is fixed to the base plate by welding a washer attached to the anchor bolt to the base plate on-site (see, for example, Patent Document 3).

JP 2013-213333 A Japanese Patent No. 5907447 JP 2008-13912 A

However, in the first to third conventional examples, the anchor bolt embedded in the concrete structure is subjected to not only the axial tensile force (pulling force) of the anchor bolt but also the radial shear force of the anchor bolt from the fixed object. In order to ensure the strength against such loads, the anchor bolts have to be made thicker and there are an increased number of them, which creates the problem of a correspondingly larger base plate. In particular, in concrete structures where reinforcing bars are arranged at high density, there is a problem that the thicker diameter and increased number of anchor bolts make it difficult to place the anchor bolts due to interference with the reinforcing bars.

In addition, in the second conventional example, the base plate cannot absorb errors in the installation position of the pre-embedded anchor bolts, so if the installation precision is low, the shear force is not evenly distributed to each anchor bolt.

Furthermore, in the third conventional example, the washer before welding can absorb errors in the installation position of the anchor bolt. However, since the washer needs to be welded on-site, welding work in narrow areas becomes difficult, and if the spacing between the anchor bolts is increased to ensure welding space, the base plate becomes larger.

It is also known that a base plate is provided with a stud to prevent shearing, thereby reducing the shear force applied to the anchor bolt. In this case, the axial pull-out force of the anchor bolt is also applied to the stud, but because the stud is usually designed as a resistance member only to shear forces, there is a problem in that the strength of the stud cannot be ensured sufficiently against the pull-out force.

The present invention was made in consideration of the above problems, and its purpose is to provide an anchor device in which the pull-out force on the anchor bolt is not applied to the anti-slip member, and the shear force on the anti-slip member is not applied to the anchor bolt.

In order to achieve the above object, the present invention provides an anchor device for fixing an object to a concrete structure, comprising: a first base plate arranged with one surface in the thickness direction facing the surface of the concrete structure; a slip-stop member provided on one surface in the thickness direction of the first base plate and embedded in the concrete structure; a second base plate arranged on the other surface in the thickness direction of the first base plate with one surface in the thickness direction facing the object to be fixed to the other surface in the thickness direction; an anchor member embedded in the concrete structure; and an anchor bolt having one end engaged with the other surface in the thickness direction of the second base plate and the other end connected to the anchor member. The first and second base plates are provided with a through-portion through which the other end of the anchor bolt can be inserted in the axial direction and can move in a direction perpendicular to the axial direction, and the first and second base plates are engaged with each other so that the movement of the anchor bolt in the axial direction is permitted and the movement of the anchor bolt in the direction perpendicular to the axial direction is restricted.

As a result, when a pull-out force (tensile force) occurs in the axial direction from the fixed object to the anchor bolt, the pull-out force is transmitted in sequence to the second base plate, the anchor bolt, and the anchor member, and the support force of the anchor member becomes the resistance force against the pull-out force. At that time, since the second base plate is engaged with the first base plate so as to be movable in the axial direction of the anchor bolt, the pull-out force on the anchor bolt is not transmitted to the first base plate, and the pull-out force is not applied to the anti-slip member of the first base plate. Also, when a shear force occurs in a direction perpendicular to the axial direction of the anchor bolt from the fixed object, the shear force is transmitted in sequence to the second base plate, the first base plate, and the anti-slip member, and the support force of the anti-slip member becomes the resistance force against the shear force. At that time, since the second base plate is engaged with the first base plate so as to restrict movement in a direction perpendicular to the axial direction of the anchor bolt, the shear force is reliably transmitted from the second base plate to the first base plate. In addition, the anchor bolt is inserted through the through-holes of the first and second base plates so that it can move in a direction perpendicular to the axial direction of the anchor bolt, so no shear force is applied to the anchor bolt from the second base plate.

According to the present invention, the pull-out force on the anchor bolt is not applied to the stud, and the shear force of the anti-slip member is not applied to the anchor bolt, so the transmission path of the pull-out force and shear force applied from the fixed object side can be reliably separated between the anchor bolt and the anti-slip member. This allows the anti-slip member to be designed with an appropriate strength as a member that resists only shear forces, and the strength of the anti-slip member against shear forces can be sufficiently ensured. In addition, the anchor bolt can be made thinner and the number of bolts can be reduced, so the first and second base plates can be made smaller.

FIG. 1 is a front view of an anchor device according to an embodiment of the present invention; Plan view of the anchor device A-A line cross-sectional view Side view of anchor device Cross-sectional view along line B-B Partially exploded side view of the anchor device Partially exploded perspective view of the anchor device A front view showing the installation process of the anchor device A front view showing the installation state of the anchor device. Schematic front view showing the state of transmission of pull-out force to the anchor bolt Schematic front view showing how shear force is transmitted to the stud FIG. 13 is a front cross-sectional view of a main part showing a modified example of the recessed portion. FIG. 11 is a plan view showing a modified example of the engagement member; FIG. 13 is a front view showing another example of installation of the anchor device.

Figures 1 to 11 show one embodiment of the present invention, illustrating an anchor device for fixing an object to a concrete structure.

This anchor device includes a first base plate 10 that is placed on the surface of the concrete structure 1 with one side (lower side) in the thickness direction facing the surface of the concrete structure 1, a second base plate 20 that is placed on the other side (upper side) in the thickness direction of the first base plate 10 with one side (lower side) in the thickness direction facing the surface of the first base plate 10 with an object to be fixed to the other side (upper side) in the thickness direction, an anchor member 30 that is embedded in the concrete structure 1, an anchor bolt 40 that has one end (upper end) engaged with the upper surface of the second base plate 20 and the other end (lower end) connected to the anchor member 30, and a disk-shaped engagement member 50 that engages the first base plate 10 and the second base plate 20.

The first base plate 10 is made of a rectangular flat steel material and is arranged so that its thickness direction is perpendicular to the surface of the concrete structure 1. The first base plate 10 is provided with a plurality of through holes 11 as through-holes that penetrate in the thickness direction, and each anchor bolt 40 is inserted into each through hole 11 in the thickness direction of the first base plate 10. Each through hole 11 has an inner diameter larger than the outer diameter of the anchor bolt 40 (for example, 2 to 3 times the outer diameter of the anchor bolt 40), and is provided in a row on both ends of the first base plate 10 in the front-rear direction, and is arranged at equal intervals along the long side of the first base plate 10. A circular recess 12 that engages with the lower side of the engagement member 50 is provided on the upper surface of the first base plate 10, and the recess 12 is formed to a depth smaller than the thickness dimension of the first base plate 10.

In addition, a plurality of studs 13 are provided on the underside of the first base plate 10 as anti-slip members. Each stud 13 is made of a rod-shaped steel material extending in the thickness direction of the first base plate 10, and its upper end is joined to the underside of the first base plate 10 by welding or the like, and its lower end is formed so as to expand in the radial direction. The studs 13 are provided in a row on each of both ends in the width direction of the first base plate 10, and are arranged at equal intervals along the short side of the first base plate 10, and are arranged in a staggered manner between the row of through holes 11 on one end side of the first base plate 10 in the front-rear direction and the row of through holes 11 on the other end side of the first base plate 10 in the front-rear direction. In addition, a plurality of screw holes 15 into which temporary fixing bolts 14 as temporary fixing members are screwed are provided on the peripheral side of the first base plate 10.

The second base plate 20 is made of a rectangular flat steel material and is arranged so that its thickness direction is perpendicular to the surface of the concrete structure 1. The second base plate 20 is formed so that its front-rear dimensions and width dimensions are equal to those of the first base plate 10, and is placed on the upper surface of the first base plate 10 so that its long and short sides match the positions of the long and short sides of the first base plate 10. The second base plate 20 is provided with a plurality of through holes 21 as through-holes that penetrate in the thickness direction, and each anchor bolt 40 is inserted into each through hole 21 in the thickness direction of the second base plate 20. Each through hole 21 has an inner diameter larger than the outer diameter of the anchor bolt 40 (an inner diameter equal to the through hole 11 of the first base plate 10), and is provided in the same position and in the same number as each through hole 11 of the first base plate 10. In addition, a circular recess 22 is provided on the underside of the second base plate 20 with which the upper side of the engagement member 50 engages, and the recess 22 is formed to a depth smaller than the thickness dimension of the second base plate 20.

In addition, plate-shaped fixing members 23 to which a fixed object (not shown) is fixed are joined to the upper surface of the second base plate 20, and the fixing members 23 are provided at locations in the front and rear at intervals so that the thickness direction is the front-rear direction. A plurality of plate-shaped ribs 24 fixed to the upper surface of the second base plate 20 are joined to one surface in the thickness direction of each fixing member 23, and each rib 24 is arranged at intervals in the width direction of the second base plate 20 so that the through hole 21 is located between them. Note that the fixing members 23 are shaped according to the size and load of the fixed object, so the illustration is simplified in this embodiment. In addition, a plurality of bolt insertion holes 25 through which temporary fixing bolts 14 are inserted are provided on the peripheral side of the second base plate 20, and each bolt insertion hole 25 is provided at the same position and in the same number as the screw holes 15 of the first base plate 10.

The anchor members 30 are made of multiple channel steels extending in the width direction of each base plate 10, 20, and are arranged in pairs spaced apart in the front-rear direction. Each anchor member 30 is connected by a connecting member 31 extending in the front-rear direction, and two connecting members 31 are provided on the upper and lower sides of each anchor member 30, and are joined to each anchor member 30 by welding or the like. In this case, a gap is provided between the pair of anchor members 30 arranged in the front and between the pair of anchor members 30 arranged in the rear, allowing the anchor bolt 40 to be inserted in the vertical direction.

The anchor bolt 40 is made of a round bar-shaped steel material, and a threaded portion 41 is formed on each of both ends. The upper end side of the anchor bolt 40 is inserted through the through holes 11, 21 of the first and second base plates 10, 20, and is inserted through a first bearing plate 42 as a first locking member arranged above the second base plate 20, a second bearing plate 43 as a second locking member arranged below the first base plate 10, and an elastic plate 44 as an elastic member 44. The first bearing plate 42 is arranged between a nut 45 screwed onto the anchor bolt 40 and the upper surface of the second base plate 20, and is locked to the upper surface of the second base plate 20. The second bearing plate 43 is arranged between another nut 45 screwed onto the anchor bolt 40 and the lower surface of the first base plate 10, and is locked to the lower surface side of the first base plate 10 via an elastic plate 44. The first bearing plate 42 is made of a rectangular steel plate larger than the through hole 21, and has a hole 42a through which the anchor bolt 40 passes. The second bearing plate 43 is made of a disc-shaped steel plate larger than the through hole 11, and has a hole 43a through which the anchor bolt 40 passes. The elastic plate 44 is made of an elastically deformable member such as rubber, and is made of a disc-shaped steel plate larger than the through hole 11 and with an outer diameter equal to that of the second bearing plate 43, and has a hole 44a through which the anchor bolt 40 passes.

The lower end of the anchor bolt 40 passes between adjacent anchor members 30, and also passes through a third bearing plate 46 arranged above the anchor member 30 and a fourth bearing plate 47 arranged below the anchor member 30. The lower end of the anchor bolt 40 is fixed to the anchor member 30 together with the third and fourth bearing plates 46, 47 by being fastened with a plurality of nuts 48 that screw into the threaded portion 41. The third and fourth bearing plates 46, 47 are made of rectangular steel plates that are larger than the distance between the adjacent anchor members 30, and the fourth bearing plate 47 has a thickness dimension larger than that of the third bearing plate 46.

The engaging member 50 is made of a disk-shaped steel material and is disposed between the opposing surfaces of the first base plate 10 and the second base plate 20. The engaging member 50 has an outer diameter dimension equivalent to the inner diameter dimension of the recesses 11, 12 of the first and second base plates 10, 20, and a thickness dimension equivalent to the combined depth dimension of each recess 11, 12. The engaging member 50 has an upper side engaged with the recess 22 of the second base plate 20, and a lower side engaged with the recess 12 of the first base plate 10. As a result, the first base plate 10 and the second base plate 20 are engaged with each other by the engaging member 50 so that the movement of the anchor bolt 40 in the axial direction is permitted and the movement of the anchor bolt 40 in a direction perpendicular to the axial direction is restricted.

In the anchor device configured as described above, first, as shown in FIG. 8, each anchor bolt 40 with an anchor member 30 fixed to its lower end is embedded in the concrete structure 1. At this time, the upper end of each anchor bolt 40 and the portion where each stud 13 is to be placed are boxed out of the concrete structure 1 to form a boxed out portion 1a that is a space where no concrete exists.

Next, the first and second base plates 10, 20, which have been temporarily fixed to each other by the temporary fixing bolts 14, are fixed to the upper end side of each anchor bolt 40 by the first bearing plate 42, the second bearing plate 43, the elastic plate 44, and each nut 45. At this time, since the elastic plate 44 is interposed between the lower surface of the first base plate 10 and the first bearing plate 42, the elastic deformation of the elastic plate 44 allows the anchor bolt 40 to move in one axial direction (upward) and in a direction perpendicular to the axial direction.

After this, post-cast concrete (e.g., non-shrink mortar) is poured into the box-out portion 1a of the concrete structure 1, and each stud 13 is embedded in the concrete structure 1 as shown in FIG. 9, and each temporary fixing bolt 14 is removed. At this time, since the through-hole 11 of the first base plate 10 is closed by the elastic plate 44, the post-cast concrete does not flow into the through-hole 11.

Here, the load transmission path in the anchor device will be explained based on Figures 10 and 11. Note that the colored parts in Figures 10 and 11 indicate the load transmission path.

First, as shown in FIG. 10, when a pulling force (tensile force) is generated in the axial upward direction of the anchor bolt 40 from the fixed object (not shown) to the fixed member 23, the pulling force is transmitted in sequence to the second base plate 20, the first bearing plate 42, the anchor bolt 40, and the anchor member 30, and the support force of the anchor member 30 becomes the resistance force against the pulling force. At that time, since the second base plate 20 is engaged with the first base plate 10 via the engagement member 50 so as to be movable in the axial direction of the anchor bolt 40, the pulling force to the anchor bolt 40 is not transmitted to the first base plate 10, and the pulling force is not applied to each stud 13 of the first base plate 10. In addition, the pulling force to the anchor bolt 40 is also applied to the second bearing plate 43, but since an elastic plate 44 is interposed between the second bearing plate 43 and the first base plate 10, the pulling force transmitted from the second bearing plate 43 to the first base plate 10 is absorbed by the elastic deformation of the elastic plate 44.

Next, as shown in FIG. 11, when a shear force is generated in the fixing member 23 from the fixed object (not shown) in a direction perpendicular to the axial direction of the anchor bolt 40, the shear force is transmitted in sequence to the second base plate 20, the engagement member 50, the first base plate 10, and the stud 13, and the bearing pressure of each stud 13 becomes the resistance force against the shear force. At that time, since the second base plate 20 is engaged with the first base plate 10 via the engagement member 50 so as to restrict the movement in a direction perpendicular to the axial direction of the anchor bolt 40, the shear force is reliably transmitted from the second base plate 20 to the first base plate 10. In addition, since the anchor bolt 40 is inserted through the through holes 11, 21 of the first and second base plates 10, 20 in a direction perpendicular to the axial direction of the anchor bolt 40 (in the radial direction of the through holes 11, 21) so as to be movable, the shear force from the second base plate 20 is not applied to the anchor bolt 40.

In this way, according to this embodiment, the first base plate 10, which transmits the shear force generated in a direction perpendicular to the axial direction of the anchor bolt 40 to the stud 13, and the second base plate 20, which transmits the pull-out force generated in the axial direction of the anchor bolt 40 to the anchor bolt 40, are engaged with each other so that the movement of the anchor bolt 40 in the axial direction is permitted and the movement of the anchor bolt 40 in a direction perpendicular to the axial direction is restricted, and the anchor bolt 40 is inserted into the through holes 11, 21 of the first and second base plates 10, 20 so as to be movable in a direction perpendicular to the axial direction of the anchor bolt 40. Therefore, the pull-out force and shear force applied from the fixing member 23 can be reliably separated between the anchor bolt 40 and the stud 13.

As a result, the pull-out force on the anchor bolt 40 is not applied to the stud 13, so the stud 13 can be designed with just the right strength as a member that resists only shear forces, ensuring that the stud 13 has sufficient strength against shear forces.

In addition, because no shear force is applied to the stud 13 on the anchor bolt 40, the diameter of the anchor bolt 40 can be reduced and the number of the anchor bolts 40 can be reduced, allowing the first and second base plates 10, 20 to be made smaller.

Furthermore, the anchor bolt 40 is inserted through the through holes 11, 21 of the first and second base plates 10, 20 so as to be movable in a direction perpendicular to the axial direction of the anchor bolt 40. This makes it possible to absorb errors in the installation position of the anchor bolt 40 when fastening the anchor bolt 40 embedded in the concrete structure 1 to the first and second base plates 10, 20, and also eliminates the need for on-site washer welding work as in the past, making on-site installation easy.

In addition, the engaging member 50 is disposed between the first and second base plates 10, 20 and engages with the recesses 12, 22 provided on the opposing surfaces of the first and second base plates 10, 20 in such a way that the anchor bolt 40 is permitted to move in the axial direction and the movement of the anchor bolt 40 in a direction perpendicular to the axial direction is restricted. This ensures that the shear force is transmitted between the first and second base plates 10, 20 and the pull-out force of the anchor bolt 40 is blocked by the engaging member 50.

Furthermore, a first bearing plate 42 is disposed between the nut 45 screwed onto the anchor bolt 40 and the upper surface of the second base plate 20 and engages with the upper surface side of the second base plate 20, and a second bearing plate 43 is disposed between another nut 45 screwed onto the anchor bolt 40 and the lower surface of the first base plate 10 and engages with the lower surface side of the first base plate 10 via an elastic plate 44. Therefore, the pulling force transmitted from the anchor bolt 40 to the lower surface side of the first base plate 10 can be absorbed by the elastic deformation of the elastic plate 44, and the transmission of the pulling force from the anchor bolt 40 to the stud 13 can be reliably blocked.

In addition, the through hole 11 of the first base plate 10 is closed by the elastic plate 44, which has the advantage that post-poured concrete does not flow into the through hole 11.

Furthermore, the first base plate 10 and the second base plate 20 are temporarily fixed to each other by the temporary fixing bolts 14, so that the first and second base plates 10, 20 can be temporarily fixed until installation on the concrete structure 1 is complete, and the first and second base plates 10, 20 can be easily fixed to the anchor bolts 40.

In the above embodiment, the recesses 12, 22 of the first and second base plates 10, 20 can be formed by cutting. However, as shown in FIG. 12, the recesses 12, 22 may be formed by providing through holes in the first and second base plates 10, 20 with a diameter equal to that of the locking member 50, and joining disk-shaped members 12a, 22a with a diameter equal to that of the locking member 50 to the through holes by welding or the like.

In the above embodiment, the first and second base plates 10, 20 are engaged with one locking member 50, but if the first and second base plates 10, 20 are horizontally long as shown in FIG. 13, the first and second base plates 10, 20 may be engaged with multiple locking members 50.

Furthermore, in the above embodiment, multiple studs 13 are provided as anti-slip members, but it is also possible to use a well-known anchor box as an anti-slip member.

The anchor device of the present invention can also be applied when installed on the inclined surface of a concrete structure 1 as shown in Figure 14. In this case, the anchor device is installed obliquely along the inclined surface of the concrete structure 1, and a column-shaped fixed object 60 extending vertically, for example, is fixed to the fixing member 23 of the second base plate 20.

The above embodiment is an example of the present invention, and the present invention is not limited to the above embodiment.

1...concrete structure, 10...first base plate, 11...through hole, 12...recess, 13...stud, 14...temporary fixing bolt, 20...second base plate, 21...through hole, 22...recess, 23...fixing member, 30...anchor member, 40...anchor bolt, 42...first bearing plate, 43...second bearing plate, 44...elastic plate, 45...nut, 50...engaging member, 60...object to be fixed.

Claims (6)

An anchor device for fixing an object to a concrete structure,
A first base plate is disposed with one surface in a thickness direction facing a surface of the concrete structure;
a displacement preventing member provided on one surface of the first base plate in a thickness direction and embedded in the concrete structure;
a second base plate disposed on the other surface in the thickness direction of the first base plate with one surface in the thickness direction facing the other surface in the thickness direction, and the object to be fixed is fixed to the other surface in the thickness direction;
An anchor member to be embedded in the concrete structure;
an anchor bolt having one end side engaged with the other surface side in the thickness direction of the second base plate and the other end side connected to the anchor member,
a through-portion through which the other end side of the anchor bolt is inserted in the axial direction and which allows movement in a direction perpendicular to the axial direction is provided in the first and second base plates;
An anchor device, characterized in that a first base plate and a second base plate are engaged with each other so that movement of the anchor bolt in the axial direction is permitted and movement of the anchor bolt in a direction perpendicular to the axial direction is restricted. 2. The anchor device according to claim 1, further comprising an engaging member that is disposed between the first and second base plates and engages with a recess provided on each of the opposing surfaces of the first and second base plates so as to permit movement of the anchor bolt in an axial direction and restrict movement of the anchor bolt in a direction perpendicular to the axial direction. a first locking member that is disposed between a nut that is screwed onto the anchor bolt and the other surface of the second base plate in the thickness direction and that locks onto the other surface of the second base plate in the thickness direction;
3. The anchor device according to claim 1, further comprising a second locking member that is disposed between another nut that is screwed onto the anchor bolt and one thickness surface of the first base plate and that locks onto the one thickness surface side of the first base plate via an elastic member. 4. The anchor device of claim 3, wherein the resilient member is configured to close the through-hole in the first base plate. 5. The anchor device according to claim 1, further comprising a temporary fixing member capable of temporarily fixing the first base plate and the second base plate to each other. 6. An anchor device according to claim 1, 2, 3, 4 or 5, wherein the shear stop comprises a plurality of studs spaced apart from one another in a direction perpendicular to the axial direction of the anchor bolt.

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