JP7027197B2 - Sheath joint with shear key function, PC floor slab, and PC floor slab connection method - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention is a sheath for inserting a PC steel material embedded in a reinforced concrete precast member (hereinafter referred to as a PC member) or a reinforced concrete precast deck (hereinafter referred to as a PC deck) to which prestress is applied and connected. Regarding sheath joints that connect each other. More specifically, the present invention relates to a sheath joint with a sheer key function that has a sheer key function as a fail-safe.

Conventionally, in the floor slab replacement work of a bridge, the bridge is replaced in half sections in order to avoid traffic congestion. At that time, the floor slab is also replaced with a PC floor slab, and when replacing each half section with a PC floor slab, prestress is applied to the lateral tightening of these bridge axis perpendicular joints by a post-tension method. And are connected.

When such a connection portion of the PC deck in the direction perpendicular to the bridge axis is prestressed at intervals of 500 mm using a steel material having a diameter of 21.8 mm or more, the friction of the prestressed joint is applied to the shearing force of the seam. You can counter it with force. However, when this prestress is loosened and the frictional force between the PC decks is reduced, there is a problem that the PC decks may be displaced in the vertical direction. Therefore, there has been a request to provide a fail-safe function in such a case.

For example, in Patent Document 1, when a plurality of concrete precast decks 11 are laid on a bridge girder in the direction of the bridge axis to construct a road, the concrete precast deck 11 is divided into two in the direction perpendicular to the bridge axis and traveled. A floor slab 11A for lanes and a floor slab 11B for overtaking lanes are formed, and the floor slabs 11A and the floor slabs 11B adjacent to each other in the direction perpendicular to the bridge axis are connected by a cotter type joint 13, and the cotter type joint 13 is released. Disclosed is a stepwise construction method of a precast deck that replaces each deck 11A for a traveling lane or every 11B for a deck for overtaking lanes (claim 1, the specification of the scope of the patent claim of Patent Document 1). See paragraphs [0043] to [0072] of the book, FIG. 9 of the drawing, etc.).

In the stepwise construction method of the precast deck of Patent Document 1, it is said that the concrete precast deck for the traveling lane or the concrete precast deck for the overtaking lane can be easily replaced.

Further, in Patent Document 2, a joint convex portion 50 is integrally provided at the joint end portion of the precast concrete slab 23, and a joint concave portion 51 is integrally formed at the joint end portion of the other precast concrete slab 43, and one of the precasts is precast. A guide pin 55 made of a material having a lower lateral elasticity coefficient than that of concrete is projected from the joint end surface of the concrete slab 43, and the guide pin 55 is provided in the guide hole portion 54 opened in the joint end surface of the other precast concrete slab 23. Construction of a concrete slab to construct a concrete slab 20 by guiding both precast concrete slabs 23 and 43 to desired positions while guiding the joint convex portion 50 into the joint concave portion 51 by inserting the joint convex portion 50. The method is disclosed (see claim 1 of the scope of patent claims in Patent Document 2, paragraphs [0060] to [0081] of the specification, FIGS. 7, 8 and the like in the drawings).

In the method for constructing a concrete deck in Patent Document 2, it is said that the position can be strictly controlled so that a step does not occur in both precast concrete slabs.

However, in the stepwise construction method of the precast deck of Patent Document 1 and the construction method of the concrete deck of Patent Document 2, when the frictional force between the PC decks is reduced, the PC decks may be displaced in the vertical direction. I couldn't solve the problem. Therefore, as a fail-safe function, even when the prestress is loosened due to an earthquake or deterioration over time and the frictional force between the PC decks is reduced, the weight of the PC decks (death) is prevented so that the decks do not shift in the vertical direction. It is required to take measures that can counter the load) and wheel load.

Further, in Patent Document 3, a tubular guide convex portion 80 that protrudes from the joint end surface and is continuous with the sheath 6 is provided at the joint end portion of one precast concrete slab 30, and the joint end of the other precast concrete slab 20 is provided. A female side guide member 7 continuous with the sheath 6 is provided in the portion, and by inserting the guide convex portion 80 into the female side guide member 7, the joining key convex portion 21 is guided into the joining key recess 31 and both precast concretes are provided. A method for constructing a concrete slab in which plates 20 and 30 are guided to each other at a desired position and sheaths 6 and 6 through which the PC tensioning material 4 is inserted is connected is disclosed (the scope of patent claims in Patent Document 3). 1, Paragraphs [0044] to [0060] of the specification, FIGS. 8 to 10 of the drawings, etc.).

The method for constructing a concrete deck described in Patent Document 3 is said to be able to perform strict position control of both precast concrete slabs and connection work of sheaths at the same time, and to efficiently construct a PC deck. However, the method for constructing a concrete deck described in Patent Document 3 has not been able to solve the above-mentioned problem.

Japanese Unexamined Patent Publication No. 2014-177767 Japanese Unexamined Patent Publication No. 2016-98490 Japanese Unexamined Patent Publication No. 2017-197999

Therefore, the present invention has been devised in view of the above-mentioned problems, and the purpose of the present invention is to move the members up and down only by shear resistance even when the prestress is loosened and the frictional force between the PC members is reduced. It is an object of the present invention to provide a sheath joint with a shear key function, a PC member, a PC deck, a PC member connecting method, and a PC deck connecting method for preventing displacement in the direction.

The sheath joint with a shear key function according to claim 1 is a sheath joint for connecting sheaths embedded in each PC deck at a connection portion for connecting PC decks, and one end thereof can be connected to each sheath. A pair of cylindrical joint bodies and a cylindrical key member that can be connected to one or both of these pair of joint bodies are provided, and the key members are subject to the weight and wheel load of the PC deck. It has a strength that can be countered by shear resistance, and is buried in one of the pair of joint bodies so that the portion exposed from the end face of the PC deck fits within the seam between the PC decks. It is possible and is configured to be able to be pulled out to the intermediate point of the pair of joint bodies, and is characterized by having a shear key function capable of countering the dead load and live load of the PC deck with shear resistance. And.

The sheath joint with a shear key function according to claim 2 is a sheath joint for connecting sheaths embedded in each PC deck at a connection portion for connecting PC decks, and one end thereof can be connected to each sheath. A pair of cylindrical joint bodies and a cylindrical key member that can be connected to one or both of these pair of joint bodies are provided, and the key members are subject to the weight and wheel load of the PC deck. The key member has a strength that can be countered by shear resistance, and the key member is configured to be screwable to one of the pair of joint bodies and to be loosely fitted to the other . It is characterized by having a shear key function that can counteract dead load and live load with shear resistance .

The sheath joint with a shear key function according to claim 3 is the sheath joint with a shear key function according to claim 2 , and the key member can be substantially embedded so as to be screwed into one of the pair of joint main bodies and fit between the seams. It is characterized by being configured.

The PC deck according to claim 4 is a PC deck made of reinforced concrete having a sheath through which a PC steel material is inserted, and a cylindrical joint body having one end connected to the sheath is embedded in the PC deck. A cylindrical key member having a strength that can withstand its own weight and wheel load by shear resistance is contained in the joint body so that the portion exposed from the end face fits within the seam with another adjacent PC deck. It is characterized in that it can be buried and can be pulled out to an intermediate point between the joint body and the joint body embedded in the other PC deck .

The PC deck according to claim 5 is characterized in that, in the PC deck according to claim 4 , reinforcing bars that oppose the split tensile stress acting on concrete are embedded around the joint body.

The PC deck connecting method according to claim 6 is a PC deck connecting method in which prestress is applied with a PC steel material to connect the PC decks to each other, and one end thereof is connected to a sheath through which the PC steel material is inserted. A cylindrical key member having a strength that can withstand the weight and wheel load of each PC deck of the PC deck with shear resistance is connected to the cylindrical joint body embedded in the PC deck. The process and the joint body in which the key member housed in the joint body of the PC deck is embedded in the joint body and another PC deck after the PC deck is placed on the main girder. It is characterized by having a key member withdrawal process for drawing out to the intermediate point of the above.

According to the inventions according to claims 1 to 3 , the sheath joint with a shear key function prevents the decks from shifting in the vertical direction even when the prestress is loosened as a fail-safe and the frictional force between the PC decks is reduced. be able to. For this reason, even if the prestress decreases due to various causes such as earthquakes and aging deterioration, such as when the decks of bridges are replaced with PC decks in half sections, there is no risk of the decks shifting in the vertical direction and replacement. The durability and reliability of the later deck will be improved.
Further, according to the inventions according to claims 1 to 3, the sheaths and the PC decks can be connected to each other simply by connecting the key member to the joint body, and the PC decks can be efficiently connected to each other in a short time. be able to.

In particular, according to the invention of claim 2 , if the key member is screwed to one of the pair of joint main bodies, the sheaths can be connected to each other simply by fitting and fitting into the other joint main body. Therefore, the PC decks can be connected to each other more efficiently and in a short time.

In particular, according to the invention of claim 3 , the key member can be stored in the PC deck almost completely. Therefore, when the PC floor slab is lifted by the lifting machine, it is possible to prevent the protruding key member from coming into contact with something and being damaged or caught.

According to the inventions according to claims 4 to 5 , when the PC decks are connected to each other, the sheath joint with the shear key function loosens the prestress as a fail-safe, and even if the frictional force between the PC decks is reduced, the decks are connected to each other. Can be prevented from shifting in the vertical direction.

In particular, according to the invention of claim 5 , in addition to the above-mentioned action and effect, even if the prestress is reduced and the stress is concentrated on the sheath joint with the shear key function, the circumference of the sheath joint of the PC deck is It is possible to suppress the occurrence of split fracture.

According to the invention of claim 6 , even when the prestress between the connected PC decks is loosened and the frictional force between the PC decks is reduced, the sheath joint with the shear key function allows the decks to move in the vertical direction. It is possible to prevent the displacement. Therefore, the sheath joint itself functions as a fail-safe when an abnormality occurs in prestress. For this reason, even if the prestress decreases due to various causes such as earthquakes and aging deterioration, such as when the decks of bridges are replaced with PC decks in half sections, there is no risk of the decks shifting in the vertical direction and replacement. The durability and reliability of the later deck will be improved.
Further, according to the invention of claim 6, when the PC floor slab is lifted by a lifting machine or the like, the protruding key member is prevented from coming into contact with something and being damaged or caught, and is short. PC decks can be connected to each other efficiently in time.

It is a vertical sectional view which shows the sheath joint with the shear key function which concerns on embodiment of this invention cut along the axial direction. It is a vertical cross-sectional view along the bridge axis right angle direction which shows the connection part which connects PC floor slabs which concerns on embodiment of this invention. It is a figure which shows the connection part as above, and (a) shows the connection part which concerns on this embodiment. Further, (b) shows a shear key type connection portion which is a modification of the connection portion, and (c) shows a cast-in-place shear key type connection portion. It is a process explanatory view which shows the preceding part erection process of the PC deck connecting method which concerns on embodiment of this invention, and (a) is the vertical sectional view along the bridge axis orthogonal direction which shows the connection part which connects PC decks to each other. , (B) is a partially enlarged cross-sectional view showing only the sheath joint of the connection portion. It is a process explanatory view which shows the process of erection of the trailing part of the PC floor slab connection method of the same above, (a) is the vertical sectional view which shows the said connection part, (b) is the partial enlarged sectional view which shows only the sheath joint of the said connection part. It is a figure. It is explanatory drawing which shows the key member drawing process of the same PC floor slab connection method, (a) is the vertical sectional view which shows the said connection part, (b) is the partial enlarged sectional view which shows only the sheath joint of the said connection part. be. It is a process explanatory view which shows the prestress introduction process of the same PC floor slab connection method, (a) is the vertical sectional view which shows the said connection part, (b) is the partial enlarged sectional view which shows only the sheath joint 1 of the said connection part. It is a figure.

Hereinafter, an embodiment for carrying out a sheath joint with a shear key function, a PC member, a PC deck, a PC member connecting method, and a PC deck connecting method according to the present invention will be described in detail with reference to the drawings.

<Sheath joint>
First, with reference to FIG. 1, a sheath joint 1 which is a sheath joint with a shear key function according to an embodiment of the present invention will be described. A PC floor slab will be illustrated as a PC member. FIG. 1 is a vertical cross-sectional view showing the sheath joint 1 cut along the axial direction.

As shown in FIG. 1, the sheath joint 1 includes a pair of cylindrical joint bodies 2 and 2'and a cylindrical key member 3 that can be connected to either of these pair of joint bodies 2 and 2'. , Consists of. This sheath joint 1 is used at a connection portion (seam G) for connecting PC decks (S1 and S2) described later along a bridge axis orthogonal direction Y orthogonal to the bridge axis direction X as a lateral tightening by a post-tension method. It is a bridge axis orthogonal direction joint connecting the sheaths S3 embedded in each PC deck (S1, S2). Further, the sheath joint 1 has a shear key function as a fail-safe, as will be described later.

(Joint body)
The joint main body according to the present embodiment is composed of a first joint main body 2 embedded in the first PC floor slab S1 and a second joint main body 2'embedded in the second PC floor slab S2. It is a pair of left and right members. Both the first joint main body 2 and the second joint main body 2'consist of cylindrical main body portions 20, 20'. The main body portions 20 and 20'are provided with sheath connecting portions 21 and 21', which are one end portions connected to the sheath S3, and key connecting portions 22, 22', which are one end portions connected to the key member 3. ..

The main bodies 20 and 20'are made of metal castings (cast iron), and the outer diameter (φ78 mm) of the key connection parts 22 and 22'is larger than the outer diameter (φ70 mm) of the sheath connection parts 21 and 21'. It is formed. Further, the main body portions 20 and 20'are embedded so that the end faces of the key connection portions 22 and 22'are exposed from the end faces on the seam G side of the PC deck (S1, S2), and are embedded in the main body portions 20 and 20'. A PC steel material that applies post-tension prestress is inserted.

Of course, the main body portions 20 and 20'are not limited to castings, and it goes without saying that they may be made of metal such as steel members or other materials such as resin. In short, the main body according to the present invention is not limited to a specific material, and may be able to withstand a predetermined shearing force, and may have a shear-key function as a fail-safe. However, the main body is inexpensive and economical because it is made of a metal casting (cast iron).

The sheath connecting portions 21 and 21'have an inner diameter (φ54 mm) slightly larger than the outer diameter (φ52 mm) of the sheath S3. Further, on the inner peripheral surface of the sheath connecting portions 21 and 21', thread grooves 23 and 23'that are screwed with the threads formed on the outer periphery of the sheath S3 are formed so that they can be screwed to the outside of the sheath S3. ing.

Further, the key connecting portion 22 of the first joint body 2 is formed with a circumferential surface 24 having an inner diameter (φ62 mm) slightly larger than the outer diameter (φ60 mm) of the key member 3, and the outer side of the key member 3 is formed on the circumferential surface 24. It is loosely fitted to and can be fitted.

On the other hand, the key connection portion 22'of the second joint body 2'is formed with a thread groove 24'that is screwed with a thread 31 described later formed on the outer peripheral surface of the key member 3, and is formed in the second joint body 2'. The key member 3 can be screwed.

The key connection portion 22'of the second joint main body 2'is a key connection portion of the first joint main body 2 so that the key member 3 is screwed into the key connection portion 22'(between the seams G). It is set longer than 22. Therefore, when the key member 3 is completely screwed into the key connection portion 22', the key member 3 is substantially buried in the second joint body 2', and the key member 3 is exposed from the end surface of the second PC deck S2. The part to be used is designed to fit between the seams G.

(Key member)
The key member 3 includes a steel cylindrical key body portion 30 having a thickness of 8 mm, an inner diameter of φ44 mm, and an outer diameter of φ60 mm, and a screw screwed into the above-mentioned thread groove 24'on the outer peripheral surface of the key body portion 30. A mountain 31 is formed.

The key member 3 is a so-called ring shear key that exerts a shear key function for connecting the first joint main body 2 and the second joint main body 2'. Here, in order to exert the shear key function, it is necessary to have at least a strength capable of countering the own weight of the PC deck (S1, S2), which is a dead weight, with shear resistance. Of course, it is preferable to be able to counter the load (Total load) obtained by adding the design wheel load (live load) of the vehicle traveling on the PC deck (S1, S2) to the dead load. Needless to say.

Specifically, assuming that the key member 3 alone bears the load obtained by adding the wheel load of 100 kN to the dead load, does the shear stress degree τs of the key member 3 become an allowable stress degree of 80 N / mm ² or less? It was confirmed. The cross-sectional area As of the key member 3 is 1306.9 mm ² , the shear stress degree τs = 76.5 N / mm ² , and the condition is satisfied.

Although the example in which the key member 3 is screwed to the second joint body 2'has been described as an example, the key member 3 may be screwed to the first joint body 2. In short, it is desirable that the key member 3 is screwed to one of the floor slabs and the other is loosely fitted to be free. This is because because it is free, only the shearing force acts on the key member 3, and the bending stress is not transmitted. Further, it goes without saying that the joining of the joint body and the key member is not limited to screwing, and other known joining methods may be used. However, it is desirable that the joint body and the key member can be easily attached and detached.

According to the sheath joint 1 according to the embodiment of the present invention described above, the prestress is loosened as a fail-safe, and the frictional force between the first PC deck S1 and the second PC deck S2 is caused by some cause. Even if it is lowered, it is possible to prevent the seam G between the decks from shifting in the vertical direction.

Further, according to the sheath joint 1, the sheaths S3 can be connected to each other simply by loosely fitting the key member 3 to the first joint body 2, and the PC decks can be efficiently connected to each other in a short time. ..

In addition, according to the sheath joint 1, the key member 3 can be substantially completely housed in the PC deck. Therefore, when the PC floor slab is lifted by the lifting machine, it is possible to prevent the protruding key member from coming into contact with something and being damaged or caught.

<PC floor version>
Next, with reference to FIG. 2, a PC deck (S1, S2) will be described as an example of a PC member provided with a sheath joint with a shear key function according to an embodiment of the present invention. FIG. 2 is a vertical cross-sectional view taken along a direction perpendicular to the bridge axis showing a connection portion connecting PC decks according to an embodiment of the present invention.

As shown in FIG. 2, the first PC floor slab S1 and the second PC floor slab S2 are prestressed and connected. The first PC deck S1 and the second PC deck S2 are both precast decks made of reinforced concrete in which predetermined reinforcing bars R1 are arranged, and the pretensioned PC steel PC1 is a bridge shaft. A prestressed concrete deck buried along the perpendicular direction Y.

Further, the joint between the first PC deck S1 and the second PC deck S2 in the direction perpendicular to the bridge axis is posted by the PC steel PC2 inserted into the sheath S3 pre-embedded in these decks. Prestress is applied by the tension method, and they are pressed against each other and joined.

The sheath S3 is a resin sheath having an inner diameter of φ45 mm and an outer diameter of φ52 mm, which is made of a resin such as polyethylene resin. Of course, it goes without saying that the sheath according to the present invention may be made of any material as long as it is a sheath in which a predetermined PC steel material can be inserted and can be connected to the sheath joint 1. ..

As described above, since the joint in the direction perpendicular to the bridge axis Y is prestressed, if the prestress by the PC steel PC2 is sound, the first PC deck S1 and the second PC deck S2 The shearing force acting on the seam G between the two can be countered by the frictional force between the end faces of the PC decks (provided that the joint material is present) due to prestress.

However, there is a demand for a fail-safe function that prevents the seam G from shifting in the vertical direction even when the prestress becomes abnormal due to deterioration over time or an earthquake. Therefore, the sheath joint 1 with a shear key function described above is installed in the seam G between the PC decks (S1 and S2) according to the embodiment of the present invention.

Specifically, the above-mentioned first joint body 2 is embedded in the first PC floor slab S1, and the above-mentioned second joint body 2'is embedded in the second PC floor slab S2. Then, the above-mentioned key member 3 is arranged so as to be bridged between the first joint main body 2 and the second joint main body 2'.

Therefore, even if the prestress in the direction perpendicular to the bridge axis is reduced and the frictional force acting between the decks is reduced, the key member 3 exerts the function of the shear key and the seam G moves up and down. It is possible to prevent the displacement in the direction.

However, as described above, even if the key member 3 has a strength that can withstand the dead weight by the shear resistance, when the shearing force acts, the key member 3 and the sheath joint 1 are subjected to the strength. Stress is concentrated. Therefore, the concrete around the first joint body 2 and the second joint body 2'to which the shear stress is transmitted may be cracked or the like by the split tensile stress acting through the sheath joint 1.

Therefore, around the first joint main body 2 and the second joint main body 2'of the first PC floor slab S1 and the second PC floor slab S2 according to the present embodiment, the reinforcing bar SP that opposes the split tensile stress Is arranged. This reinforcing bar SP is a spiral D13 reinforcing bar (Urubon D13 of High Frequency Neturen Co., Ltd .: registered trademark) in order to obtain a high concrete binding force with a small amount of reinforcement.

Here, as shown in FIG. 3A, the shape of the seam G according to the present embodiment is such that the end faces of all the floor slabs are linear, the total joint width is about 20 mm, and the lower end face is One of them protrudes and the width of the lower end of the joint is about 5 mm. Therefore, it is possible to easily prevent the joint mortar from leaking with a urethane sponge or the like.

As shown in FIG. 3B, the shape of the seam G may be a shear key type seam G'in which the convex portion and the concave portion are fitted to each other. The filler to be filled in the joint of this seam G'is an adhesive. Therefore, there is a risk of deterioration over time.

Further, as shown in FIG. 3 (c), it is also possible to use a cast-in-place shear key type joint G in which the recesses face each other. It is necessary to consider the filler to be filled in the joint in order to shorten the time.

According to the PC floor slab (S1, S2) provided with the sheath joint with the shear key function according to the above-described embodiment, since the reinforcing reinforcement SP is arranged, in addition to the action and effect of the sheath joint 1, the split It can withstand tensile stress and suppress cracking.

<PC floor slab connection method>

Next, a PC deck connecting method will be described as a PC member connecting method according to the embodiment of the present invention with reference to FIGS. 4 to 7. The case of replacing the existing concrete deck with a PC deck for each half section of the bridge will be described.

(Preceding part erection process)
FIG. 4 is a process explanatory view showing a process of erection of a preceding portion of the PC deck connecting method according to the present embodiment, in which FIG. A vertical cross-sectional view along the direction, (b) is a partially enlarged cross-sectional view showing only the sheath joint 1 of the connection portion.

First, in the PC deck connecting method according to the present embodiment, the half cross section of the existing concrete deck S'placed on the plurality of main girders H1 is removed, and as shown in FIG. 4A, the half cross section is removed. The leading portion erection step is performed in which the above-mentioned first PC floor slab S1 which is the leading portion is placed between the main girders H1 and erected. At this time, as shown in FIG. 4B, only the first joint main body 2 embedded in the first PC deck S1 is present in the sheath joint 1.

5A and 5B are process explanatory views showing a step of erection of a trailing portion of the PC deck connecting method according to the present embodiment, where FIG. 5A is a vertical cross-sectional view showing the connecting portion and FIG. 5B is a sheath of the connecting portion. It is a partially enlarged sectional view which shows only the joint 1.

(Posting section erection process)
Next, in the PC deck connecting method according to the present embodiment, the remaining existing concrete deck is removed, and as shown in FIG. 5A, the above-mentioned second PC deck S2, which is a trailing portion, is used. A trailing section erection process is performed in which the main girder is placed between the main girders H1 and erected. At this time, as shown in FIG. 5B, the sheath joint 1 is in a state in which the key member 3 is already screwed into the second joint body 2'embedded in the second PC deck S2. There is.

That is, before performing the step of erection of the trailing portion, a step of screwing the second joint body 2'to the key member 3 is performed. This process should be carried out before the trailing part erection process is performed at the PC floor slab manufacturing factory or the construction site where the PC floor slab is installed.

As described above, when the key member 3 is completely screwed into the key connection portion 22', the key member 3 is substantially buried in the second joint body 2', and the key member 3 is the second PC floor slab S2. The portion exposed from the end face of the seam is designed to fit between the seams G. Therefore, in the present trailing portion erection process, the key member 3 does not get in the way even if the second PC floor slab S2 is vertically lowered when the second PC floor slab S2 is hung in the immediate vicinity of the first PC floor slab S1. Therefore, the working time of this process can be shortened.

(Key member extraction process)
6A and 6B are explanatory views showing a key member drawing process of the PC deck connecting method according to the present embodiment, in which FIG. 6A is a vertical cross-sectional view showing the connection portion, and FIG. 6B is only the sheath joint of the connection portion. It is a partially enlarged sectional view which shows.

Next, in the PC floor slab connecting method according to the present embodiment, a key member withdrawal step of turning and pulling out the key member from the placed second PC floor slab S2 is performed. In this step, specifically, a tool is inserted into the seam G, and the key member 3 screwed into the second joint body 2'is turned to be pulled out from the second joint body 2'to a predetermined position. The position for pulling out the key member 3 is such that the key member 3 is just at an intermediate point between the first joint main body 2 and the second joint main body 2'.

(Prestress introduction process)
7A and 7B are process explanatory views showing a prestress introduction step of the PC deck connecting method according to the present embodiment, FIG. 7A is a vertical cross-sectional view showing the connection portion, and FIG. 7B is a sheath joint of the connection portion. It is a partially enlarged sectional view which shows only 1.

Next, in the PC deck connecting method according to the present embodiment, the PC steel material PC2 is inserted through the sheath S3, and after the filler material filled in the seam G is hardened and a predetermined strength is developed, the PC steel material PC2 is tensioned. Then, the prestress introduction process of introducing prestress by the post-tension method is performed. As the filler, mortar, grout, an adhesive or the like is usually used.

As described above, the PC deck connecting method according to the present embodiment is completed, and the first PC deck S1 placed on the main girder H1 as the leading portion and the second PC deck S2 installed as the trailing portion. And are firmly connected by prestress.

According to the PC deck connecting method according to the present embodiment described above, even when the prestress between the connected PC decks is loosened and the frictional force between the PC decks is reduced, the sheath joint 1 with a shear key function is used. Thereby, it is possible to prevent the seam G between the floor slabs from being displaced in the vertical direction. Therefore, the sheath joint 1 itself functions as a fail-safe when an abnormality occurs in prestress.

Further, according to the PC floor slab connecting method according to the present embodiment, in addition to the above-mentioned effects, when the PC floor slab is lifted by a lifting machine, the protruding key member may come into contact with something and be damaged. , Can be prevented from getting caught. Therefore, the step of erection of the trailing portion can be performed in a short time, the working time of the entire PC deck connecting method can be shortened, and the PC decks can be efficiently connected to each other. Further, it is not necessary to move the trailing portion in the horizontal direction to fit the key member 3.

The sheath joint with a shear key function, the PC deck, and the PC deck connecting method according to the embodiment of the present invention have been described in detail above, but any of the above-mentioned or illustrated embodiments are specific in carrying out the present invention. It merely shows one embodiment. Therefore, the technical scope of the present invention should not be construed in a limited manner by these. In particular, the PC floor slab has been described as an example as the PC member, but the PC member is not limited to the PC floor slab, and the present invention can be applied to any precast member made of reinforced concrete to which prestress is applied and connected. it is obvious.

1: Sheath joint (sheath joint with shear key function)
2: First joint body (joint body)
2': Second joint body (joint body)
20, 20': Main body 21, 21': Sheath connection 22, 22': Key connection 23, 23': Thread groove 24: Circumferential surface 24': Thread groove 25: Air injection hole 3: Key member 30 : Key body 31: Thread G: Seam (joint)
S1: First PC floor slab (PC floor slab)
S2: Second PC floor slab (PC floor slab)
S': Existing concrete deck PC1: (Pretension) PC steel PC2: (Post-tension) PC steel S3: Sheath SP: Reinforcing bar X: Bridge axis method Y: Bridge axis perpendicular direction

Claims (6)

It is a sheath joint that connects the sheaths embedded in each PC deck at the connection part that connects the PC decks.
Each sheath comprises a pair of cylindrical joint bodies to which one end can be connected and a cylindrical key member to which one or both of these pair of joint bodies can be connected.
This key member has a strength that can withstand the own weight and wheel load of the PC deck with shear resistance, and the portion exposed from the end face of the PC deck is within the joint between the PC decks. It is configured so that it can be buried in one of the pair of joint bodies so that it fits in, and can be pulled out to the intermediate point of the pair of joint bodies.
A sheath joint with a shear key function, which has a shear key function capable of countering the dead weight and live load of the PC deck with shear resistance. It is a sheath joint that connects the sheaths embedded in each PC deck at the connection part that connects the PC decks.
Each sheath comprises a pair of cylindrical joint bodies to which one end can be connected and a cylindrical key member to which one or both of these pair of joint bodies can be connected.
This key member has strength that can withstand the own weight and wheel load of the PC deck with shear resistance.
The key member is configured to be screwable to one of the pair of joint bodies and to be loosely fitted to the other .
A sheath joint with a shear key function, which has a shear key function capable of countering the dead weight and live load of the PC deck with shear resistance. The sheath joint with a shear key function according to claim 2 , wherein the key member is configured to be screwed into one of the pair of joint bodies so as to be substantially embedded so as to fit between the seams. A PC deck made of reinforced concrete with a sheath through which PC steel is inserted.
A portion in which a cylindrical joint body having one end connected to the sheath is embedded, and a cylindrical key member having a strength that can withstand the own weight and ring load of the PC deck with shear resistance is exposed from the end face. Can be buried in the joint body so that it fits within the seam between the other adjacent PC decks, and can be pulled out to the intermediate point between the joint body and the joint body embedded in the other PC decks. A PC floor slab characterized by being attached . The PC deck according to claim 4 , wherein a reinforcing bar that opposes the split tensile stress acting on the concrete is embedded around the joint body. It is a method of connecting PC decks by applying prestress with PC steel to connect PC decks to each other.
One end is connected to the sheath through which the PC steel material is inserted, and the cylindrical joint body embedded in the PC deck is countered by shear resistance against the own weight and ring load of each PC deck of the PC deck. The process of connecting a cylindrical key member with possible strength ,
After the PC deck is placed on the main girder, the key member housed in the joint body of the PC deck is embedded in the joint body and another PC deck at an intermediate point between the joint body and the joint body. A PC deck connecting method characterized by having a key member withdrawal process.

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