JP2021031902A - Joint structure for concrete precast member - Google Patents

Abstract

To significantly shorten a construction period, and to increase the placement interval of joints to facilitate quality control during erection by making it possible to increase the engagement area per joint.SOLUTION: A female joint 3 consisting of a groove-type engaging part 6 having a groove-shaped cross section in a plan view and a female joint anchor part 7 extending rearward thereof is embedded in a joint end surface of a precast member 1A on one side with a joint 2 as a boundary at prescribed intervals in the horizontal direction with a vertical groove 5 facing the outside. A male joint 4 consisting of a male joint anchor part 9 having a tip formed so as to project outward and a fixing part 8 that is provided at the tip of the male joint anchor part and can be inserted into the groove-type engaging part 6 is embedded in a joint end surface of a precast member 1B on the other side at prescribed intervals in the horizontal direction. The groove-type engaging part 6 is formed in a vertically long shape that is long in the vertical direction. The fixing part 8 is formed in a vertically long shape that is long in the vertical direction. The male joint anchor part 9 is formed in a flat plate shape along a plane in the vertical direction.SELECTED DRAWING: Figure 5

Description

The present invention relates to a joint structure for joining concrete precast members used for a floor slab of a bridge or the like.

Conventionally, concrete precast floor slabs manufactured in factories, site yards, etc. have been used in the floor slab replacement work for bridges and the like in order to shorten the construction period. As a joint structure for connecting the concrete precast slabs to each other, various structures have been proposed and put into practical use.

The most commonly used joint structure is the so-called loop joint. In this loop joint, as shown in FIG. 22, the loop-shaped joint reinforcing bars 51 and 52 projecting in the bridge axis direction at different positions are arranged at appropriate intervals, and the loop-shaped joints 51 and 52 are arranged in the direction perpendicular to each other. It is a joint structure 50 in which a reinforcing bar 53 is inserted from the ground, and cast-in-place concrete 54 is cast in a space between the precast floor slabs to connect adjacent precast floor slabs to each other.

Further, the application of the loop joint structure is conditional on the floor slab thickness being 240 mm or more. Therefore, when the floor slab thickness is thinner than that, for example, the "rationalized joint" shown in Patent Document 1 below. A joint structure called is used. In the "rationalized joint", as shown in FIG. 23, a fixing head 62 having a diameter larger than the diameter of the connecting reinforcing bar is formed at the tip of the linear connecting reinforcing bar 61 without using the loop reinforcing bar. On each joint side surface of the precast floor slab body, a large number of these are projected on the upper edge side and the lower edge side of the precast floor slab body at predetermined intervals in the horizontal direction, and both precast floor slab bodies are connected within the joint interval. The joint structure 60 is such that the reinforcing bars 61, 61 ... Are alternately arranged and overlapped in the horizontal direction, the reinforcing bars 63 are arranged at predetermined positions, and then cast-in-place concrete 64 is placed within the joint interval.

Further, various mechanical joints have been conventionally proposed in which labor saving is achieved by eliminating the installation of reinforcing bars in the filling portion and the construction period is shortened by reducing the filling material. For example, in addition to the simplest mechanical joint (for example, see Patent Document 2 below) in which a male joint is fitted to a female joint fitting having a grooved cross section, Patent Document 3 below includes a concrete precast floor slab and the like. It is a joint structure for joining the plate-shaped concrete structures of the above to each other in a state of being arranged in the plane direction, and at least an upper opening upward and a peripheral opening communicating with the upper opening in a part of the peripheral portion thereof. The axis of the first joint fitting having a substantially U-shaped cross section and having a fitting hole inside the fitting hole is attached to both joint ends of the concrete structure to be joined to each other. Is placed along the thickness direction of the concrete structure or diagonally with respect to the thickness direction, and the upper opening faces the upper surface and the peripheral opening faces the joint end face, and the fitting is made from each opening. The holes are buried in a state of communicating with the outside, the peripheral openings of the first joint fittings are opposed to each other, and in the facing state, the connecting portion extending over the peripheral openings of the first joint fittings and the connecting portion. A second joint fitting that is integrally formed at both ends of the first joint fitting and has a fitting portion that is housed inside the first joint fitting and that cannot be detached from the peripheral opening. Each concrete structure to be joined by inserting it from the upper opening into the fitting hole of the joint fitting is connected, and the inside of the fitting hole is filled with a solidifying material to fit the first joint fitting and the second joint fitting. Disclosed is a joint structure of a concrete structure, which is characterized in that the and is fixed to each other.

Further, in Patent Document 4 below, a C-shaped joint fitting having a groove hole having a lip groove type cross section is opposed to each other, and a cotter having an H type cross section is inserted into a groove hole that is united in an H shape and fastened. In the joint device, bolt holes are drilled in the vicinity of the central portion of the left and right flange portions of the cotter having an H-shaped cross section, and the C-shaped joint fitting has a bottom surface portion having a predetermined thickness. A cotter type joint device is disclosed, characterized in that a locking portion for a bolt to be inserted into the bolt hole is provided on the bottom surface portion.

Japanese Unexamined Patent Publication No. 2015-1045 Japanese Patent Application Laid-Open No. 2017-190629 Public Relations Japanese Unexamined Patent Publication No. 7-71195 Japanese Unexamined Patent Publication No. 2001-214964

The mechanical joint structure described above is superior to others in that it can minimize restrictions due to lane restrictions and traffic restrictions by shortening the construction period and minimize the impact on surrounding traffic. However, in the case of the so-called "cotter type joint" as in Patent Documents 3 and 4, excessive accuracy is required for erection of the floor slab in order to insert the H-shaped cotter, which makes it difficult to insert the cotter. In the unlikely event that such a situation occurs, there is concern that it may cause a significant delay in the process. Further, the so-called "cotter type joint" as in Patent Documents 3 and 4 has a problem that the manufacturing cost is high and the construction cost is greatly affected.

Further, as in Patent Document 2, in a joint structure in which a male joint provided with a circular fixing member at the tip of a reinforcing bar is fitted to a female joint having a groove-shaped cross section, a female joint and a male joint are used at each location. Since the engagement area of the floor slabs is small, in order for the floor slabs to have a constant connection strength as a whole, the joint arrangement interval must be reduced and many joints must be installed on the joint end faces. For this reason, there is a problem that it takes time and effort in manufacturing, and the narrower the joint spacing is, the more the positioning accuracy at the time of erection is required, which makes it difficult to control the accuracy.

Therefore, the main problem of the present invention is to eliminate the installation of reinforcing bars in the filling portion to save labor, reduce the filling material, and stabilize the construction efficiency by facilitating the alignment and the like. A mechanical joint structure of concrete precast members that can shorten the construction period and increase the engagement area per joint to increase the joint placement interval and facilitate quality control during erection. To provide.

In order to solve the above problems, the present invention according to claim 1 is a joint structure for joining concrete precast members to each other.
From the groove-shaped engaging part having a groove-shaped cross section in a plan view and the female joint anchor part extending behind it at a predetermined interval in the horizontal direction on the joint end surface of the concrete precast member on one side of the joint part. The female joint is buried with the vertical groove facing the outside.
A male joint anchor portion whose tip is formed so as to protrude outward at predetermined intervals in the horizontal direction on the joint end surface of the concrete precast member on the other side of the joint portion, and the groove type engagement provided at the tip thereof. A male joint consisting of a fixing part that can be inserted into the part is embedded,
The female joint of the concrete precast member on one side is engaged with the male joint of the concrete precast member on the other side, and the concrete precast members are connected to each other. The ground material is filled in the gap between the upper space and / or the lower space of the engaging portion and the concrete precast member on one side and the concrete precast member on the other side.
The groove-shaped engaging portion is formed in a vertically long shape that is long in the vertical direction, the fixing portion is formed in a vertically long shape that is long in the vertical direction, and the male joint anchor portion is formed in a flat plate shape along a vertical plane. Provided is a joint structure of a concrete precast member, characterized in that it is formed of.

In the invention according to claim 1, a state in which a female joint having a groove-shaped engaging portion having a groove-shaped cross section in a plan view on a concrete precast member on one side of the joint portion faces the vertical groove to the outside. A male joint is embedded in a concrete precast member on the other side of the joint portion, and these female joints and the male joint are engaged with each other, and the concrete precast members are connected to each other. The grout material is filled in the gap between the internal space of the engaging portion, the upper space and / or the lower space of the grooved engaging portion, and the concrete precast member on one side and the concrete precast member on the other side. As a result, the concrete precast members are joined to each other.

Since it has a simple mechanical engagement structure in which the fixing portion of the male joint is engaged with the groove type engaging portion of the female joint, the allowable range of error is large, and the alignment can be performed by absorbing the manufacturing error and the construction error. Since it can be easily performed, the construction period can be significantly shortened. The grout material is filled with the internal space of the grooved engaging portion, the upper space and / or the lower side space of the grooved engaging portion, and the concrete precast member on one side and the concrete precast member on the other side. Since it is a gap portion and the filling amount of the grout material can be reduced, the working time can be shortened and the construction cost can be reduced. Furthermore, since the gap between the concrete precast members is small, the size of the concrete precast members can be increased to the limit of the transportation conditions, and the number of concrete precast members installed can be increased as compared with the conventional loop joint. Can be reduced by about 10 to 20%.

Further, in the joint structure according to the present invention, the groove-shaped engaging portion of the female joint is formed in a vertically long shape that is long in the vertical direction, and the fixing portion of the male joint inserted in the groove-shaped engaging portion is also vertically and vertically. Since the male joint anchor portion that is formed in a vertically long shape that is long in the direction and extends behind the fixing portion is formed in a flat plate shape along the vertical plane, it is formed at the tip of the reinforcing bar like a conventional mechanical joint. Compared to a structure in which a male joint provided with a circular fixing member fits into a female joint, it has a vertically long engaging structure that is longer in the vertical direction, so that the engagement area between the female joint and the male joint is per location. Increases and the joint strength increases. Therefore, even if the arrangement interval of the joints is increased, a constant connection strength between the precast members can be ensured, the number of joints can be reduced, and quality control at the time of erection can be facilitated.

The present invention according to claim 2 provides the joint structure of the concrete precast member according to claim 1, wherein the female joint anchor portion is formed in a flat plate shape along a plane in the vertical direction.

In a structure in which the tip of the reinforcing bar is welded or friction-welded to the rear surface of the female joint as in Patent Document 2, the joint strength between the reinforcing bar and the female joint is low, and the structure tends to be unstable. On the other hand, in the invention according to claim 2, since the female joint anchor portion extending behind the groove type engaging portion is formed in a flat plate shape along the vertical plane, the groove type engaging portion is formed. The integrally formed female joint anchor portion stabilizes the structure of the female joint.

The concrete according to claim 3, wherein the female joint anchor portion and the male joint anchor portion are arranged independently of the reinforcing bars arranged on the concrete precast member. A joint structure for precast members is provided.

In conventional mechanical joints, male joints and female joints are directly connected to the force distribution bars extending in the bridge axis direction, so the installation position of the joints may be restricted in relation to the force distribution bars, and design is free. There was a problem that the degree was low. On the other hand, in the invention according to claim 3, the joint structure can be improved independently of the force distribution bar, so that the joint strength can be improved and the degree of freedom in design can be improved.

According to the fourth aspect of the present invention, there is provided a joint structure of a concrete precast member according to any one of claims 1 to 3, wherein the female joint is manufactured by a mold casting method.

The invention according to claim 4 defines the material of the female joint. The female joint is preferably manufactured by a mold casting method having a high degree of freedom in shape. On the other hand, the male joint may be manufactured by a mold casting method like the female joint, or may be manufactured by a flat plate such as a steel plate.

The present invention according to claim 5 provides a joint structure of a concrete precast member according to any one of claims 1 to 4, which is filled with concrete instead of the grout material.

In the invention according to claim 5, concrete is filled instead of the grout material in order to reduce the construction cost.

According to the sixth aspect of the present invention, a plurality of ridges or dents extending in a predetermined direction are formed on the outer surface of the female joint at intervals in a direction orthogonal to the extending direction of the ridges or dents. The joint structure of the concrete precast member according to any one of claims 1 to 5 is provided.

In the invention according to claim 6, the fixability of the female joint is enhanced by forming an uneven fixing portion on the outer surface of the female joint.

The present invention according to claim 7 provides the joint structure of the concrete precast member according to any one of claims 1 to 6, wherein the concrete precast member is a floor slab.

In the invention according to claim 7, a floor slab used for a bridge or the like is used as the concrete precast member.

As described in detail above, according to the present invention, labor saving is achieved by eliminating the installation of reinforcing bars in the filling portion, and in addition to the effects such as reduction of the filling material, the construction efficiency is reduced by reducing the number of installations and facilitating the alignment. Precast concrete member that can be stabilized and the construction period can be shortened significantly, the engagement area per joint can be increased, the joint arrangement interval can be increased, and the accuracy control at the time of erection can be facilitated. It is possible to provide a mechanical joint structure of.

It is a top view which shows concrete precast floor slabs 1A, 1B. It is the II-II sectional view. FIG. 3 is a sectional view taken along line III-III of FIG. It is an enlarged plan view of the joint part 2. It is a VV cross-sectional view of FIG. FIG. 6 is a sectional view taken along line VI-VI of FIG. It is VII-VII sectional view of FIG. The female joint 3 is shown, (A) is a front view, (B) is a plan view, (C) is a left side view, (D) is a right side view, and (E) is an E-E sectional view of (B). It is a floor slab perspective view which shows the male joint 4. The male joint 4 is shown, (A) is a front view, (B) is a plan view, (C) is a left side view, and (D) is a right side view. It is (A)-(C) of the procedure diagram of the joining procedure of the precast floor slab. It is a top view which shows the concrete precast floor slabs 1A, 1B which concerns on the modification. It is the XIII-XIII sectional view. It is a cross-sectional view of XIV-XIV of FIG. The female joint 3 according to another form example is shown, (A) is a front view, (B) is a top view, (C) is a left side view, (D) is a right side view, (E) is a bottom view, ( F) is a vertical sectional view (FF sectional view of (B)). FIG. 5 is an enlarged cross-sectional view of a main part of the outer surface of the female joint 3 (XVI-XVI cross-sectional view of FIG. 15C). FIG. 5 is an enlarged cross-sectional view of a main part of the outer surface of the female joint 3 (XVII-XVII cross-sectional view of FIG. 15 (D)). A male joint 4 according to another embodiment is shown, (A) is a front view, (B) is a top view, (C) is a left side view, and (D) is a right side view. It is a front view of the vertical groove 5 which concerns on a modification. It is sectional drawing of the joint part 2 which concerns on the modification. It is a perspective view which shows the embedded state of the female joint 3. It is a vertical cross-sectional view which shows the conventional loop joint. It is a vertical cross-sectional view which shows the conventional rationalized joint.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The present invention is a mechanical joint structure for joining concrete precast floor slabs (hereinafter, simply referred to as precast floor slabs). In general, in the case of mechanical joints, compared to conventional loop joints and rationalized joints, labor can be saved by eliminating the installation of reinforcing bars in the filling part, and the construction period can be significantly shortened by reducing the filling material. However, there are drawbacks such as the joint itself is expensive, the construction cost is high, and high accuracy is required for alignment. Therefore, the present invention proposes a mechanical joint structure having a simple structure, capable of absorbing a predetermined amount of error, and excellent in alignment workability.

Specifically, as shown in FIGS. 1 to 3, the joint structure has a predetermined interval in the horizontal direction (direction perpendicular to the bridge axis) on the joint end surface of the precast floor slab 1A on one side of the joint portion 2 as a boundary. Then, in a plan view, a female joint 3 composed of a groove-shaped engaging portion 6 having a groove-shaped cross section and a female joint anchor portion 7 extending behind the groove-shaped engaging portion 6 is embedded with the vertical groove 5 facing the outside, and the joint portion is formed. A male joint anchor portion 9 having a tip protruding outward at predetermined intervals in the horizontal direction on the joint end surface of the precast floor slab 1B on the other side of the boundary of 2, and the female joint 3 provided at the tip thereof. A male joint 4 composed of a fixing portion 8 that can be inserted into the groove type engaging portion 6 is embedded.
As shown in FIGS. 4 to 7, the female joint 3 of the precast floor slab 1A on one side is engaged with the male joint 4 of the precast floor slab 1B on the other side, that is, the groove type engagement of the female joint 3. The fixing portion 8 of the male joint 4 is inserted into the portion 6 so that both floor slabs are joined to each other, and the internal space IS of the groove type engaging portion 6, the upper space US of the groove type engaging portion 6, and one side. It is a joint structure in which the grout material 18 is filled in the gap portion M between the precast floor slab 1A and the precast floor slab 1B on the other side.

Hereinafter, the details will be described in more detail.

First, the female joint 3 provided on the precast floor slab 1A on one side will be described in detail with reference to FIGS. 4 to 8.

As shown in detail in FIG. 8, the female joint 3 has a groove-type engaging portion 6 having a groove-shaped cross section in a plan view in which a vertical groove 5 is formed on the front end surface, and the groove-shaped engaging portion 6. It is a metal member composed of an end face on which the vertical groove 5 of the portion 6 is formed and a female joint anchor portion 7 extending rearward from the end face facing the end face.

The groove-shaped engaging portion 6 has a box-like shape in which the upper surface is opened and the vertical groove 5 along the vertical direction is formed on the front surface in communication with the opening upper surface. The bottom surface of the groove-type engaging portion 6 may be opened in the same manner as the top surface, but as shown in FIG. 8 (E), a bottom plate for closing the bottom portion is provided to provide a bottomed groove-type cross section. Is preferable. This makes it possible to prevent the groove-type engaging portion 6 from opening to both sides. Further, an opening (not shown) for communicating the filler may be provided in the central portion of the bottom surface of the groove type engaging portion 6.

The groove-shaped engaging portion 6 is formed in a vertically long shape that is long in the vertical direction. That is, the height H in the front view shown in FIG. 8A is formed to have a larger dimension than the width B and the depth C in the plan view shown in FIG. 8B. The height H of the groove-shaped engaging portion 6 is preferably 1.2 to 3 times, preferably 1.5 to 2 times, the width B or the depth C. The height H of the groove-shaped engaging portion 6 is preferably about 50 to 90%, preferably about 60 to 80%, with respect to the thickness of the precast floor slab 1A, and is substantially at the center of the precast floor slab 1A in the thickness direction. It is better to place it in a position.

As shown in FIG. 8, the width dimension B of the groove type engaging portion 6 is approximately 80 to 150 mm, preferably 100 to 130 mm, and the depth dimension C is equal to or less than the width dimension B. It is preferably about 60 to 120 mm, preferably 70 to 100 mm.

As shown in FIG. 8D, the width S of the vertical groove 5 formed in the groove type engaging portion 6 is 20 to 60 mm, preferably 30 to 50 mm, and constitutes the male joint 4 described later. The size is 110 to 220%, preferably 120 to 200% of the thickness of the male joint anchor portion 8. The ratio of the male joint anchor portion 8 to the thickness is preferably set to an appropriate numerical range because the allowable range of manufacturing error or construction error is closely related. Further, if this ratio is made too large, the engagement of the male joint 4 with the fixing portion 8 becomes small, and the joint strength decreases. Therefore, it is desirable to form the male joint 4 at a predetermined ratio. When the upper end portion of the vertical groove 5 is formed wide as shown in FIG. 19 (when the inclined portion 5a described later is provided), the width S excludes the wide portion (inclined portion 5a) of the upper end portion. It is the width dimension of the part where both side edges are parallel.

The vertical groove 5 may be formed so as to penetrate in the vertical direction from the upper end edge to the lower end edge of the groove type engaging portion 6, but as shown in FIG. 8, the length from the upper end edge to the lower half is halfway. It is preferable that the U-shaped vertical groove is formed by the vertical groove. By connecting the lower end portion as a U-shaped vertical groove, it is possible to prevent the vertical groove 5 from opening to both sides. Further, the flutes 5 may be formed to have substantially the same width over the entire length as shown in FIG. 8D, or may be formed at the upper end of the flutes 5 as shown in FIG. , An inclined portion 5a in which the groove width gradually increases toward the upper side may be provided. By providing the inclined portion 5a, when the precast floor slab 1B on the other side is dropped from above, the protruding male joint anchor portion 8 can be easily inserted into the vertical groove 5.

As shown in FIGS. 4 and 5, in a state where the precast floor slab 1A on one side and the precast floor slab 1B on the other side are joined, a male joint is formed so as to project from the joint end surface of the precast floor slab 1B on the other side. The anchor portion 8 is inserted into the vertical groove 5, and the fixing portion 8 provided at the tip of the male joint anchor portion 8 is inserted into the internal space of the groove type engaging portion 6.

As shown in FIG. 8, the female joint anchor portion 7 extending rearward of the groove-shaped engaging portion 6 is preferably formed in a flat plate shape along a plane in the vertical direction. The female joint anchor portion 7 extends rearwardly by a predetermined length from the central portion of the wall surface facing the wall surface on which the vertical groove 5 of the groove type engaging portion 6 is formed. The rear end of the female joint anchor portion 7 is provided with a rear end fixing portion 7a that protrudes on both sides and has a flat plate shape along a plane parallel to the joint end surface.

The height dimension of the female joint anchor portion 7 is preferably formed to be substantially the same width over the entire length, and is 30 to 100%, preferably 40 to 60% with respect to the height H of the groove type engaging portion 6. It is better to say.

The female joint anchor portion 7 is preferably arranged independently of the bridge axial reinforcing bar arranged on the precast floor slab 1A. That is, the stress in the bridge axial direction acting on the female joint 3 is substantially supported only by the female joint anchor portion 7, and does not act on the reinforcing bars in the bridge axial direction. In this way, by providing the female joint anchor portion 7 independently of the bridge axial reinforcing bar, the degree of freedom in design can be improved in the arrangement of the bridge axial reinforcing bar, and when connecting to the bridge axial reinforcing bar, the degree of design freedom can be improved. , It is difficult to apply to curved or inclined reinforcing bars, but in the case of the female joint 3 according to the present invention, which is arranged independently of the reinforcing bars, it can be applied as long as it does not interfere with adjacent reinforcing bars. It will be possible.

Further, the length of the female joint anchor portion 7 in the bridge axis direction is preferably 1.2 to 3 times, preferably 1.5 to 2 times, the depth C of the groove type engaging portion 6. It is not necessary to provide the precast floor slab 1A over the entire length in the bridge axis direction. As described above, since the length of the female joint anchor portion 7 is short and it is not connected to the reinforcing bar in the bridge axial direction, it is easy to handle the precast floor slab 1A at the time of manufacturing, and the handleability is improved.

In order to dispose the female joint 3 on the precast floor slab 1A on one side, as shown in FIGS. 4 and 5, the groove type engaging portion 6 externally removes the opening and the vertical groove 5 on the upper surface from the joint end surface. The female joint anchor portion 7 is placed in a state of being completely embedded inside the skeleton of the precast floor slab 1A.

As a manufacturing method of the female joint 3, it is desirable to manufacture the female joint 3 by a mold casting method capable of increasing the degree of freedom in shape. As a result, the groove type engaging portion 6 and the female joint anchor portion 7 can be integrally formed, and the joint portion main body and the anchor portion are integrated without welding, pressure welding, bolt fastening, or the like to form a structure. It is stabilized, there is no concern about fatigue damage, a high-strength joint structure can be obtained, and the precast floor slab 1A can be easily manufactured. Further, by manufacturing by the mold casting method, the adhesive strength with concrete is increased, and the fixability of the female joint 3 is improved.

Next, the male joint 4 provided on the precast floor slab 1B on the other side will be described with reference to FIGS. 4 to 6, 9 and 10.

As shown in FIG. 9 and FIG. 10 in detail, the male joint 4 includes a male joint anchor portion 9 whose tip side is provided so as to project from the joint end surface of the precast floor slab 1B and whose base end side is embedded in concrete. It is a metal member provided at the protruding tip of the male joint anchor portion 9 and composed of a fixing portion 8 that can be inserted into the groove type engaging portion 6 of the female joint 3.

The fixing portion 8 is a wide portion protruding from both sides of the male joint anchor portion 9 in a plan view shown in FIG. 10 (B), and is an upper surface in the internal space of the groove-shaped engaging portion 6 of the female joint 3. It is formed so that it can be inserted downward from the opening.

The fixing portion 8 is formed in a vertically long shape that is long in the vertical direction. That is, the height K of the fixing portion 8 in the front view shown in FIG. 10A is formed to have a larger dimension than the width D of the fixing portion 8 in the plan view shown in FIG. 10B. The height K of the fixing portion 8 is preferably 60 to 90%, preferably 70 to 80%, with respect to the height H of the groove type engaging portion 6, as shown in FIG. With the precast floor slabs 1A and 1B joined, it is preferable to arrange the precast floor slabs 1A and 1B substantially at the center in the vertical direction of the groove type engaging portion 6.

The width D of the fixing portion 8 is formed to have substantially the same width over the entire length in the vertical direction, and is formed so as to have substantially the same protruding width from both sides of the male joint anchor portion 9 extending rearward thereof. The width D of the fixing portion 8 is formed to have a size larger than the width S of the vertical groove 5 formed in the groove type engaging portion 6, and as shown in FIG. 6, the fixing portion 8 is formed in the groove type engaging portion 6. In the state of being inserted into the joint end surface, both side portions of the fixing portion 8 and both sides of the vertical groove 5 have an overlap margin U with respect to the direction orthogonal to the joint end surface (bridge axis direction). Since this overlapping allowance U is formed over the entire length of the fixing portion 8 in the height direction, the engagement area between the female joint 3 and the male joint 4 becomes large, and the joint strength between the female joint 3 and the male joint 4 is increased. You will be able to increase it.

The male joint anchor portion 9 extending behind the fixing portion 8 is formed in a flat plate shape along a plane in the vertical direction. One end of the male joint anchor portion 9 having such a flat plate shape protrudes from the joint end surface of the precast floor slab 1B on the other side, is connected to the center portion in the width direction of the fixing portion 8 in the vertical direction, and the other end is the other. It is arranged in a state of being embedded inside the skeleton of the precast floor slab 1B on the side. At the rear end of the male joint anchor portion 9, a rear end fixing portion 9a having a flat plate shape that protrudes on both sides in a plan view shown in FIG. 10B and is parallel to the joint end surface is provided. There is.

The male joint anchor portion 9 and the fixing portion 8 are formed so that the height of the male joint anchor portion 9 and the height of the fixing portion 8 are substantially the same at these connecting portions, and the upper and lower ends of the male joint anchor portion 9 and the fixing portion 8 are substantially the same. It is preferable to form. As a result, the stress acting on the fixing portion 8 can be substantially evenly distributed by the entire male joint anchor portion 9.

In the embodiment shown in FIG. 10A, the height of the male joint anchor portion 9 is formed at a relatively small height behind the intermediate portion. The ratio of the height of the rear portion formed at a relatively small height to the height of the front portion formed at a relatively large height is 40 to 80%, preferably 55 to 75%. It is good to do. When changing the height, if a step portion or the like whose height changes suddenly is provided, stress concentrates there and causes damage. Therefore, as shown in the illustrated example, the inclined portion 9b whose height gradually changes is provided. It is preferable to provide it. The slope of the inclined portion 9b is preferably 30% or less, preferably 20% or less with respect to the direction in which the male joint anchor portion 9 extends. The inclined portion 9b may be provided at either the upper or lower end of the male joint anchor portion 9, but it is preferably formed in a tapered shape by providing the inclined portion 9b at both the upper and lower end edges as shown in the illustrated example. The inclined portion 9b is preferably formed in a portion of the male joint anchor portion 9 embedded in concrete of the precast floor slab 1B, and the portion protruding from the joint end surface is substantially equal to the height K of the fixing portion 8. It is preferably formed at the same constant height. On the other hand, as shown in FIG. 20, the male joint anchor portion 9 may be formed so as to have a substantially uniform height over the entire length. As a result, the fixing strength of the male joint anchor portion 9 can be further increased. At this time, the fixing portion 8 and the rear end fixing portion 9a connected to the front end edge and the rear end edge of the male joint anchor portion 9 are formed at substantially the same height as the height of the male joint anchor portion 9. Is preferable.

The plate thickness T of the male joint anchor portion 9 may be formed with substantially constant dimensions over the entire length, or may be changed. In any case, the groove type engaging portion 6 is formed to have a size smaller than the width S of the vertical groove 5.

As a method for manufacturing the male joint 4, steel plates may be joined by welding or the like, but it is preferably manufactured by a mold casting method capable of increasing the degree of freedom in shape. By manufacturing by the mold casting method, the fixing portion 8 and the male joint anchor portion 9 can be integrally formed, and the joint portion main body and the anchor portion can be integrated without welding, pressure welding, bolt fastening, or the like. As a result, the structure is stabilized, there is no concern about fatigue damage, a high-strength joint structure can be obtained, and the precast floor slab 1B can be easily manufactured. Further, by manufacturing by the mold casting method, the adhesive strength with concrete is increased, and the fixability of the male joint 4 is improved.

(How to combine precast floor slabs 1A and 1B)
As shown in FIG. 11 (A), the male joint 4 of the precast floor slab 1B that follows in the following order with respect to the groove type engaging portion 6 of the female joint 3 of the precast precast floor slab 1A that has already been installed. The precast floor slab 1B is installed while the fixing portion 8 is dropped in the vertical direction from the upper side, and the two are aligned (FIG. 11 (B)). In the connection between the female joint 3 and the male joint 4, as shown in FIG. 11B, the male joint anchor portion 9 protruding from the joint end surface of the male joint 4 is provided in the vertical groove 5 of the groove type engaging portion 6. At the same time, the fixing portion 8 is inserted into the internal space of the groove type engaging portion 6 of the female joint 3 so that both precast floor slabs 1A and 1B are connected. In the present invention, since the female joint 3 having the groove type engaging portion 6 and the male joint 4 having the fixing portion 8 have a simple fitting structure, the permissible value of the error is large, and the manufacturing error and the construction error are caused. It can be absorbed and aligned easily.

Next, as shown in FIG. 11C, the internal space IS of the groove type engaging portion 6, the upper space US of the groove type engaging portion 6, the precast floor slab on one side and the precast floor on the other side. The grout material 18 is filled in the gap portion M with the plate. Instead of the grout material 18, concrete may be filled.

In the above embodiment, it has been described that the female joint 3 is provided on the joint end surface of the precast floor slab 1A on one side and the male joint 4 is provided on the joint end surface of the precast floor slab 1B on the other side. When joining three or more floor slabs, a female joint 3 is provided on one opposite surface of one rectangular precast floor slab, and a male joint 4 is provided on the opposite side of the precast floor slab. Precast floor slabs are installed by joining the floor slabs in order.

When joining three or more precast floor slabs, the female joint 3 is provided on the end surface of the precast floor slab 1B that is installed as described above and is opposite to the end surface provided with the male joint 4. In the same way, a precast floor slab that follows in the next order is installed.

(Reinforcing bar 15 for opening prevention)
As shown in FIGS. 1 and 3, for preventing opening, the female joint anchor portion 7 extends in a direction parallel to the extending direction at a predetermined distance from the female joint 3 on both sides of the female joint 3. It is preferable to arrange the reinforcing bar 15. By arranging the opening prevention reinforcing bar 15, even when an excessive tensile force acts on the male joint 4, the opening direction of the vertical groove 5 (both sides of the female joint 3) is supported by the opening prevention reinforcing bar 15. Therefore, it is possible to prevent the vertical groove 5 from being deformed in the direction of opening on both sides. That is, when there is no opening prevention reinforcing bar 15, only concrete exists on both sides of the female joint 3, so that the vertical groove 5 opens and deformation is likely to occur. On the other hand, when the opening prevention reinforcing bar 15 is arranged, the concrete on both sides of the female joint 3 is reinforced by the opening prevention reinforcing bar 15, so that deformation of the vertical groove 5 in the opening direction can be suppressed.

The opening prevention reinforcing bar 15 may be a linear bar material substantially parallel to the direction in which the female joint anchor portion 7 extends, but as shown in FIGS. 4 and 5, the groove type engagement is performed in the horizontal direction. It is preferable to use a substantially U-shaped or annular reinforcing bar in which a loop portion 16 along the vertical direction is formed at a position overlapping the joint portion 6. In order to form such a loop portion 16, a rod member having a predetermined length can be formed by bending it into a semicircular arc shape at a position substantially half in the axial direction and processing it into a substantially U shape. As a result, the opening prevention reinforcing bar 15 is formed with a loop portion 16 along the vertical direction on the side portion of the groove type engaging portion 6, and is parallel to the female joint anchor portion 7 from the upper end and the lower end of the loop portion 16, respectively. As a result, the straight portions extending rearward are arranged in two upper and lower stages, and the reinforcing strength of both side portions of the female joint 3 is further increased. It is preferable that the height of the loop portion 16 is formed to be substantially the same as the height H of the groove type engaging portion 6.

The length of the opening prevention reinforcing bar 15 in the bridge axis direction is arbitrary, but it is preferably formed with a length extending rearward from the female joint 3. In the illustrated example, the precast floor slab 1A on one side is composed of a part of the joint end face side of the bridge axial reinforcing bar formed over almost the entire length in the bridge axial direction.

As shown in FIG. 5, the loop portion 16 of the opening prevention reinforcing bar 15 is arranged at a position overlapping the groove type engaging portion 6 in the horizontal direction (direction perpendicular to the bridge axis). That is, in the cross-sectional view shown in FIG. 5, the loop portion 16 of the opening prevention reinforcing bar 15 is arranged so as to overlap the groove type engaging portion 6. As a result, the area where the opening prevention reinforcing bar 15 and the groove type engaging portion 6 overlap in the horizontal direction is larger than that when the linear opening preventing reinforcing bar is simply arranged, and the vertical portion formed in the groove type engaging portion 6 is formed. It becomes possible to surely prevent the groove 5 from being deformed in the opening direction. The top of the loop portion 16 (the top of the precast floor slab 1A on the joint end face side with respect to the bridge axis direction of the opening prevention reinforcing bar 15) is the joint end face (vertical groove 5 of the female joint 3) by the amount of the concrete cover thickness. Is located behind the end face on which the was formed).

As shown in FIG. 4, the horizontal separation distance L between the groove-shaped engaging portion 6 and the opening-preventing reinforcing bar 15 is such that the vertical groove 5 of the groove-shaped engaging portion 6 is opened by the opening-preventing reinforcing bar 15. It is preferable that the thickness is 20 to 60 mm, preferably 30 to 50 mm so that

In the example shown in FIG. 1, two of the opening prevention reinforcing bars 15 are arranged between the adjacent female joints 3 and 3, and each reinforcing bar acts as an opening prevention reinforcing bar 15 of the adjacent groove type engaging portion 6. However, when the horizontal arrangement interval of the female joints 3, 3 ... Is small, only one is arranged between the adjacent female joints 3, 3 and these are the respective female joints arranged on both sides thereof. The opening prevention reinforcing bar 15 arranged on the side of 3 may also be used (not shown).

The opening prevention reinforcing bar 15 also has a function as a reinforcing bar in the bridge axial direction, is arranged over almost the entire length of the precast floor slab 1A on one side in the bridge axial direction, and as shown in FIG. 1, the other. A plurality of similar bridge axial reinforcing bars 17 are also arranged on the side precast floor slab 1B at positions aligned with the bridge axial direction.

As shown in FIG. 1, in the floor slab of the precast floor slab 1A on one side and the precast floor slab 1B on the other side, the opening prevention reinforcing bars 15 (bridge axial reinforcing bars) and the bridge axial reinforcing bars 17 Alternatively, the reinforcing bars 19 in the direction perpendicular to the bridge axis, the PC steel wire 20 in the direction perpendicular to the bridge axis 20, and the like may be arranged in the cross direction to be firmly reinforced.

[Examples of other forms]
(1) In the above embodiment, the construction procedure of fitting the male joint 4 from the upper side is performed, but conversely, when the construction procedure of fitting the female joint 3 from the upper side is performed, the female joint 3 is fitted. An open space may be provided on the lower side, and the front vertical groove 5 may be formed so as to continuously extend upward from the lower end edge. In this case, the filling space of the grout material 18 is the internal space IS of the female joint 3, the lower space of the female joint 3, and the gap portion M.

(2) In the above embodiment, the groove-shaped engaging portion 6 is formed in a box shape with a bottomed upper surface open, but is formed with a groove-shaped cross section in which both the upper surface and the lower surface are open and penetrate in the vertical direction. May be good. In this case, both the upper surface and the lower surface of the groove type engaging portion 6 are set as open spaces, and after the male joint 4 is connected, the grout material is provided in both the upper space US and the lower side space of the groove type engaging portion 6, respectively. 18 is filled.

(3) The rebar 19 in the direction perpendicular to the bridge axis and the PC steel wire 20 in the direction perpendicular to the bridge axis 20 arranged in the direction perpendicular to the bridge axis have various forms as shown in FIGS. 1 to 3 and 12 to 14. Can be placed. In the illustrated example, a plurality of reinforcing bars 19 in the direction perpendicular to the bridge axis and PC steel wires 20 in the direction perpendicular to the bridge axis are arranged at predetermined intervals in the bridge axis direction as a set in which the reinforcing bars 19 are arranged in two upper and lower stages. The bridge axis perpendicular direction reinforcing bar 19 is connected and arranged at a position orthogonal to the bridge axis direction reinforcing bar 15, and the bridge axis perpendicular direction PC steel wire 20 is separated from the bridge axis direction reinforcing bar 15 on the vertical center side. Have been placed. Therefore, the vertical separation distance of the bridge axis perpendicular direction reinforcing bar 19 is larger than the vertical separation distance of the bridge axis perpendicular direction PC steel wire 20.

In the embodiment shown in FIGS. 1 to 3, the reinforcing bars 19 in the direction perpendicular to the bridge axis and the PC steel wires 20 in the direction perpendicular to the bridge axis are alternately arranged at substantially equal intervals in the direction of the bridge axis in the region other than the vicinity of the joint end face. On the other hand, in the region near the joint end face where the female joint 3 or the male joint 4 is arranged, the bridge shaft has a relatively large vertical separation distance at a position overlapping the female joint 3 or the male joint 4. The perpendicular direction reinforcing bars 19 are continuously arranged in the bridge axis direction, and the bridge axis perpendicular direction PC steel wire 20 is continuously arranged in the bridge axis direction at a position behind the female joint 3 or the male joint 4 so as not to overlap. ing. The female joint anchor portion 7 of the female joint 3 and the male joint anchor portion 9 of the male joint 4 are arranged between the vertically separated reinforcing bars 19 and 19 in the direction perpendicular to the bridge axis and not intersecting the reinforcing bars 19 in the direction perpendicular to the bridge axis. ing.

As a modification, in the morphological examples shown in FIGS. 12 to 14, the bridge axis perpendicular direction reinforcing bars 19 and the bridge axis perpendicular direction PC steel wires 20 are alternately arranged at substantially equal intervals in the bridge axis direction. The bridge axis orthogonal direction reinforcing bar 19 and the bridge axis perpendicular direction PC steel wire 20 are also arranged at the intersections of the female joint anchor portion 7 of the female joint 3 and the male joint anchor portion 9 of the male joint 4, and the intersections thereof. The female joint anchor portion 7 and the male joint anchor portion 9 of the portion are each provided with an opening or a notch for inserting the reinforcing bar 19 in the direction perpendicular to the bridge axis or the PC steel wire 20 in the direction perpendicular to the bridge axis.

(4) As shown in FIG. 15, an uneven portion for fixing may be provided on the outer surface of the female joint 3. Specifically, a plurality of ridges 24 or dents 25 extending in a predetermined direction are formed on the outer surface of the female joint 3 at intervals in a direction orthogonal to the extending direction of the ridges 24 or 25. There is. As shown in FIG. 16, the ridge 24 is a substantially trapezoidal portion having a cross section that protrudes relatively outward, and is formed in a linear or strip shape extending in the horizontal direction or the vertical direction. Further, as shown in FIG. 17, the recess 25 is a portion having a substantially trapezoidal cross section that is relatively recessed, and is formed in a linear or strip shape extending in the horizontal direction or the vertical direction.

The ridges 24 and ridges 25 may be formed on any of the outer surfaces of the female joint 3, but the precast groove 5 is formed in the groove-type engaging portion 6. It is preferable that the concave groove 25 is formed on the front end surface to be the joint end surface of the floor slab 1A, and the convex groove 24 is formed on the other surface. When a convex portion is formed on the front end surface of the female joint 3, there is a problem that it hits the formwork at the time of manufacturing the floor slab and invades the gap between the precast floor slab 1B on the other side at the time of installation. It is preferable to form the recess 25 in which the above-mentioned recess 25 is not formed.

The direction in which the ridge 24 or the ridge 25 extends with respect to each outer surface of the female joint 3 is arbitrary, but as shown in FIG. 15, the vertical groove 5 of the groove type engaging portion 6 It is preferable to form the formed front end surface, the rear end surface to which the female joint anchor portion 7 is connected, the upper surface and the bottom surface so as to extend in the horizontal direction, and both side surfaces so as to extend in the vertical direction. Further, it is preferable that the female joint anchor portion 7 is formed with orthogonal ridges 24 along the vertical direction and the horizontal direction, respectively, on both side surfaces along the vertical plane. As a result, when the female joint 3 is manufactured by the mold casting method using a mold divided into two in the width direction along the center line CL (FIG. 15 (B)) passing through the central portion of the groove width of the vertical groove 5, the front and rear It becomes possible to increase the fixing strength of the female joint 3 against the tensile force acting in the bridge axis direction on both side surfaces and the bottom surface while ensuring the ease of pulling out the mold divided into two on the end surface and the bottom surface in the width direction. .. In the example shown in FIG. 15A, a plurality of protrusions 24 along the vertical direction are intermittently arranged on both side surfaces of the groove type engaging portion 6 at predetermined intervals, but the intervals are provided. Instead, continuous ridges may be arranged in the vertical direction. Further, in the example shown in FIG. 15A, orthogonal ridges 24 along the vertical and horizontal directions are arranged on both side surfaces of the female joint anchor portion 7, but in the vertical or horizontal direction. Only the ridges 24 along the line may be arranged. As shown in FIGS. 15A, 15B, and 15F, it is preferable to provide the ridges 24 on the upper surface of the groove-type engaging portion 6 because the fixing property of the female joint 3 is improved. In the illustrated example, of the upper surface of the groove-shaped engaging portion 6 formed in a substantially C shape, a ridge 24 extending in a direction parallel to the joint end surface is formed on the rear portion on the side opposite to the vertical groove 5. There is. In the illustrated example, the ridge 24 is provided only in the intermediate portion that does not reach the edge of the rear portion, but may be arranged so as to extend to the edge.

Further, as shown in FIG. 15 (F), it is preferable to form a plurality of convex portions 26, 26 ... Protruding inward on the inner surface of the groove-shaped engaging portion 6, respectively. The convex portion 26 is a discrete protrusion having a chevron cross section, and is provided on each of the inner surfaces facing both side surfaces of the female joint 3. By providing the convex portion 26 ..., the fixability of the male joint 4 in the groove type engaging portion 6 is improved. The convex portion 26 provided in the intermediate portion in the vertical direction is preferably formed in a chevron shape having an apex in the central portion and gradually decreasing in height toward the outside. Further, it is preferable to provide a convex portion 26 also at the upper end portion, and the convex portion 26 provided at the upper end portion is formed by a lower half portion obtained by cutting the convex portion 26 provided at the intermediate portion in the vertical direction at the upper end portion. It is preferable that the cut surface in the vertical direction is arranged flush with the upper surface of the female joint 3 and is formed in a shape in which the height gradually decreases from the end surface toward the lower side. By arranging a convex portion 26 having a top on the upper end edge at the upper end portion of the inner surface of the groove type engaging portion 6, the concrete or grout material 17 filled in the groove type engaging portion 6 is fixed. The properties are further improved, and the mortar filled in the column can be prevented from popping out due to vibration or the like.

When the male joint 4 is manufactured by a mold casting method, as shown in FIG. 18, a concavo-convex portion for fixing may be provided on the outer surface thereof, similarly to the female joint 3. Specifically, of the male joint 4, the front end surface of the fixing portion 8, both side surfaces of the male joint anchor portion 9 along the vertical plane, and the rear end surface of the rear end fixing portion 9a of the male joint anchor portion 9, respectively. , Convex 24 is formed. In addition, uneven portions can be provided on other surfaces as well. The direction in which the ridges 24 extend is arbitrary, but as shown in FIG. 18, ridges 24 extending in the horizontal direction are formed on the front surface of the fixing portion 8 and the rear surface of the rear end fixing portion 9a, and a male joint is formed. It is preferable to form orthogonal ridges 24 along the vertical and horizontal directions on both side surfaces of the anchor portion 9. As a result, when the male joint 4 is manufactured by the mold casting method using a mold in which the male joint 4 is divided into two along the central portion of the plate thickness of the male joint anchor portion 9, the front end fixing portion 9a of the fixing portion 8 and the rear end fixing portion 9a are manufactured. While ensuring the ease of pulling out the mold divided into two on the rear surface in the width direction, it becomes possible to increase the fixing strength of the male joint 4 against the tensile force acting in the bridge axis direction on both side surfaces.

(5) As a form in which the female joint 3 is arranged on the concrete of the precast floor slab 1A on one side, the male joint 4 is fixed to the groove type engaging portion 6 of the female joint 3 when the precast floor slabs 1A and 1B are connected. It is optional as long as 8 is made insertable. In the above embodiment, as shown in FIG. 21 (A), concrete is arranged above the upper surface of the groove-type engaging portion 6 and behind the rear end of the hollow portion of the groove-type engaging portion 6. Below the upper surface of the groove-type engaging portion 6, there is a stepped joint end surface in which concrete is arranged on the rear side of the front end surface of the groove-type engaging portion 6, as shown in FIG. 21 (B). In addition, the concrete on the joint end face of the precast floor slab 1A on one side may be formed flat, and the front side portion may be formed so as to protrude from the hollow portion of the groove type engaging portion 6 from the joint end face of the concrete. As shown in FIG. 21 (C), the female joint 3 is embedded in concrete to form a hollow portion of the vertical groove 5 and the groove type engaging portion 6 and a portion where concrete is not provided only in the upper portion thereof. May be good.

(6) In the above embodiment, the concrete precast floor slab has been described as an example, but it can also be used for a joint structure for joining other concrete precast members.

1A / 1B ... Concrete precast slab, 2 ... Joint part, 3 ... Female joint 4 ... Male joint, 5 ... Vertical groove, 6 ... Groove type engaging part, 7 ... Female joint anchor part, 8 ... Fixing part, 9 ... Male joint anchor part, 15 ... Reinforcing bar for opening prevention, 16 ... Loop part, 17 ... Reinforcing bar in the direction of the bridge axis, 18 ... Grout material, 19 ... Reinforcing bar in the direction perpendicular to the bridge axis, 20 ... Reinforcing bar in the direction perpendicular to the bridge axis, IS ... Internal space of the groove type engaging part, US ... Upper space of the groove type engaging part, M ... Gap portion

Claims (7)

It is a joint structure for joining concrete precast members to each other.
From the groove-shaped engaging part having a groove-shaped cross section in a plan view and the female joint anchor part extending behind it at a predetermined interval in the horizontal direction on the joint end surface of the concrete precast member on one side of the joint part. The female joint is buried with the vertical groove facing the outside.
A male joint anchor portion whose tip is formed so as to protrude outward at predetermined intervals in the horizontal direction on the joint end surface of the concrete precast member on the other side of the joint portion, and the groove type engagement provided at the tip thereof. A male joint consisting of a fixing part that can be inserted into the part is embedded,
The female joint of the concrete precast member on one side is engaged with the male joint of the concrete precast member on the other side, and the concrete precast members are connected to each other. The ground material is filled in the gap between the upper space and / or the lower space of the engaging portion and the concrete precast member on one side and the concrete precast member on the other side.
The groove-shaped engaging portion is formed in a vertically long shape that is long in the vertical direction, the fixing portion is formed in a vertically long shape that is long in the vertical direction, and the male joint anchor portion is formed in a flat plate shape along a vertical plane. A joint structure of a concrete precast member, which is characterized by being formed of. The joint structure of a concrete precast member according to claim 1, wherein the female joint anchor portion is formed in a flat plate shape along a plane in the vertical direction. The joint structure of a concrete precast member according to claim 1 or 2, wherein the female joint anchor portion and the male joint anchor portion are arranged independently of the reinforcing bars arranged in the concrete precast member. The joint structure of a concrete precast member according to any one of claims 1 to 3, wherein the female joint is manufactured by a mold casting method. The joint structure of a concrete precast member according to any one of claims 1 to 4, wherein the concrete is filled in place of the grout material. In any of claims 1 to 5, a plurality of ridges or dents extending in a predetermined direction are formed on the outer surface of the female joint at intervals in a direction orthogonal to the extending direction of the ridges or dents. The joint structure of the concrete precast member described. The joint structure of the concrete precast member according to any one of claims 1 to 6, wherein the concrete precast member is a floor slab.

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