JP6995539B2 - PCa version joint structure and its construction method - Google Patents

Description

The present invention relates to a joint structure of a PCa plate, which is a plate-shaped precast member, and a method for constructing the joint structure.

Conventionally, a pier structure has been constructed in a harbor or the like by using a PCa (precast) member which is a reinforced concrete structure manufactured in advance in a factory or the like.

For example, in Patent Document 1, a PCa girder member erected between steel pipe piles erected at predetermined intervals, which is a straight beam-shaped main body and a steel pipe pile head disposed in a part of the main body. It is composed of an annular socket portion that is externally inserted into the socket portion, and the socket portion is provided stepwise below the main body so that its top surface is located on the same plane as the bottom surface of the main body, and the socket portion is provided. A PCa girder member is disclosed above which is provided with a hooking portion that protrudes horizontally from the main body and is suspended from the top of the steel pipe pile (claims of Patent Document 1). 1. Of the above, paragraphs [0018] to [0027] of the specification, FIGS. 10 to 15 of the drawings, etc.).

On the other hand, as a deck of a bridge, a PCa (precast) deck, which is a plate-shaped reinforced concrete structure, is manufactured in advance at a factory or the like, the PCa deck is transported to a construction site, and a plurality of PCa decks are arranged at predetermined intervals. A plurality of PCa decks are integrated by laying them apart from each other and constructing a joint structure in the separated spaces.

For example, in Patent Document 2, the upper end reinforcing bars and the lower end reinforcing bars of the bridge axial direction reinforcing bars, which are the main reinforcing bars of the PCa deck slab, are projected from the end of the deck slab as joint reinforcing bars, respectively, and the joint reinforcing bars thereof are proposed. Disclosed is a joint structure of a PCa deck provided with an enlarged diameter portion that is larger than the diameter of a reinforcing bar in the direction of the bridge by fitting a crimping grip or the like to the end portion of the bridge (Patent Request of Patent Document 2). Scope claim 1, paragraphs [0016] to [0024] of the specification, FIGS. 5, 6 and the like in the drawing).

Therefore, the joint structure of the PCa deck having the joint reinforcing bar in which the enlarged diameter portion such as the crimp grip described in Patent Document 2 is formed is applied to the pier structure as shown in Patent Document 1 to the steel pipe pile. It is also conceivable to cover the steel girders with a jacket, place the PCa deck on those steel girders, and integrate the steel girder and the PCa deck with the joint structure of the PCa deck described in Patent Document 2. ..

However, in the joint structure of the PCa floor slab described in Patent Document 2, the joint length of the joint reinforcing bar needs to be 15 times or more the nominal diameter of the reinforcing bar, and concrete is cast around the joint reinforcing bar by casting a plurality of concrete. There is a problem that the width of the packing portion for integrating the PCa floor slab is increased. For this reason, there is a problem that the flange width required for the bottom plate of the packed portion becomes larger than the flange width of the steel girder required for strength, which is uneconomical. Therefore, when applying the PCa deck to the pier structure, it is required to reduce the size of the padded portion as much as possible.

Further, even when the joint structure of the PCa deck described in Patent Document 2 is applied as a deck of a normal bridge, there is a similar requirement. In other words, when the bridge is used (shared) as a road bridge, etc., and one side is renewed half by half, the width of the padded part is narrowed as much as possible to reduce the amount of concrete cast in the field, and early-strength concrete etc. is used for the padded part. There was a request to shorten the construction period such as using it.

It should be noted that the joint length of the above-mentioned joint reinforcing bar needs to be 15 times or more the nominal diameter of the reinforcing bar due to the stress acting on the joint reinforcing bar in which the enlarged diameter portion is formed due to the bending rigidity of the reinforcing bar from verification experiments and the like. This is because the length is set to suppress the brittle fracture form in which the covered concrete of the padded concrete is extruded and peeled off by a phenomenon similar to the dowel action.

Further, in Patent Document 3, a lower joint reinforcing bar and an upper reinforcing bar are provided by a lower reinforcing bar (27) and an upper reinforcing bar (28) having a shape in which a U-shaped end is folded back by bending from one reinforcing bar. A joint structure of a PCa deck surrounded from all sides of a joint reinforcing bar is disclosed.

However, the lower reinforcing bar (27) and the upper reinforcing bar (28) in the joint structure of the PCa floor slab described in Patent Document 3 suppress the occurrence of cracks in the concrete, and the amount of work for assembling the reinforcing bar and the concrete placement at the site are suppressed. It was provided for the purpose of reducing the amount. Therefore, even if the amount of concrete placed is reduced, the lower reinforcing bar (27) and the upper reinforcing bar (28) are provided without necessarily denting the joint end face (12A) and the second joint end face (12B). Since it can be placed at a predetermined position, it is possible to reduce the amount of concrete placed on site (see paragraph [0057] of Patent Document 3 and the like), and it is possible to reduce the width (dimensions) of the padded portion. It wasn't a thing.

The reason is that the lower reinforcing bars (27) and the upper reinforcing bars (28) having the same diameter as the lateral reinforcing bars arranged so as to be orthogonal to the bridge axial reinforcing bars protruding from the PCa deck as joint reinforcing bars in the padding portion. This is because the first extension portion (27C) and the second extension portion (28C), which are the fixing lengths of the above, are required to be 15 times or more the nominal diameter of the reinforcing bar according to the provisions of the road bridge specification. That is, the joint length of the joint reinforcing bar, which is required to be 15 times or more the nominal diameter of the reinforcing bar described above, cannot be reduced, and the width (dimension) of the padded portion is not reduced (see FIG. 12).

Further, in the joint structure of the PCa floor slab described in Patent Document 3, the lower joint reinforcing bar (27) and the upper reinforcing bar (28) surround and restrain the lower joint reinforcing bar and the upper joint reinforcing bar, and cracks in concrete occur. It is said to suppress. However, in the first place, if an appropriate joint structure is used as in the joint structure of the PCa deck described in Patent Document 2, cracks do not occur in the concrete, and a reinforcing bar for suppressing cracks is unnecessary.

Japanese Unexamined Patent Publication No. 2007-77575 Japanese Unexamined Patent Publication No. 2012-62664 Japanese Unexamined Patent Publication No. 2017-106231

Therefore, the present invention has been devised in view of the above-mentioned problems, and an object thereof is the width of the padded portion while suppressing the brittle fracture form in which the cover concrete is extruded and peeled off. It is an object of the present invention to provide a PCa plate joint structure capable of shortening (dimensions) and a method for constructing the same.

The PCa plate joint structure according to claim 1 is a PCa plate joint structure in which concrete is poured and integrated at a filling portion connecting the PCa plates, and the upper end reinforcement of the main bar of the PCa plate and the upper end reinforcement of the PCa plate are integrated. A plurality of joint bars extending over the upper and lower stages where the lower end bars extend to the stuffing portion, and a plurality of lateral bars extending over the upper and lower tiers arranged so as to be orthogonal to the plurality of joint bars at the stuffing portion. , And the expanded diameter portion is formed at the end of each of the plurality of joint bars, and the stress applied to the joint bar by the cover concrete on the open surface of the PCa plate is used. The fog peeling suppressing reinforcing material that prevents extruding and peeling is arranged on the vertical outside of the open surface side of the upper end and lower end bars of the plurality of joint bars and inside the enlarged diameter portion. The cover peeling suppressing reinforcing material has a horizontal U-shape with the open end where one of the four sides is open as the lower end or the upper end, and the U-shaped end is not folded back. It is characterized by.

The PCa plate joint structure according to claim 2 is the PCa plate joint structure according to claim 1. The fog peeling suppressing reinforcing material has an enlarged cross section of the fog peeling suppressing reinforcing material at the open end. It is characterized in that an enlarged portion is formed.

The method for constructing a PCa plate joint structure according to claim 3 is a method for constructing a PCa plate joint structure in which concrete is poured and integrated at a packing portion connecting PCa plates to each other, and is an upper end of a main bar. PCa plates having a plurality of joint bars in which the streaks and the lower end streaks extend outward and an enlarged diameter portion is formed at the end portion are juxtaposed at predetermined intervals to serve as the filling portion. One of the four sides that prevents the cover concrete on the open surface of the padded portion from being pushed out and peeled off by the stress acting on the joint bar after the plate parallelization step and the PCa plate parallelization step. A horizontal U-shaped shape with the open end open to the lower end or the upper end, and the cover peeling suppression reinforcing material whose U-shaped end is not folded back, is used for the upper end and lower end muscles of the plurality of joint bars. Of these, it is characterized by comprising a reinforcing material arranging step of arranging the reinforcing material on the outside in the vertical direction on the open surface side and on the inside of the enlarged diameter portion.

According to the invention according to claim 1 or 2 , a plurality of joints are provided with a cover peeling suppressing reinforcing material for preventing the cover concrete on the open surface of the PCa plate from being extruded and peeled by the stress acting on the joint reinforcement. Of the upper end and lower end bars of the bar, since they are arranged on the outer side in the vertical direction on the open surface side and on the inner side of the enlarged diameter portion, the cover concrete is extruded in the joint structure of the PCa plate. The width (dimensions) of the padded portion can be shortened while suppressing the fracture form. Therefore, when the present invention is applied to a pier structure, the width of the upper flange of the steel girder of the pier structure can be reduced, and the steel girder of the optimum design according to the strength can be obtained, which is economical. Become. In addition, even when the present invention is applied to the deck of a bridge, the width of the padding is made as narrow as possible to reduce the amount of concrete cast on site, such as by updating one side at a time while using (sharing) the bridge. The period can be shortened.
Further, according to the invention according to claim 1 or 2, the fog peeling suppressing reinforcing material has a horizontal U-shaped end having an open end in which one of the four sides is open, and the U-shaped end. Is not folded back, so that the fog peeling suppressing reinforcing material can be easily placed in a predetermined place after the PCa plate is installed. Therefore, it is possible to shorten the work time of the construction work of the joint structure of the PCa version and reduce the installation cost.

In particular, according to the invention of claim 2 , since an enlarged portion in which the cross section of the fog peeling suppressing reinforcing material is enlarged is formed at the open end of the fog peeling suppressing reinforcing material, the PCa plate is a PCa floor slab. Even if the plate thickness is thin and the fixing length cannot be obtained at the straight part up to the open end of the cover peeling inhibitor reinforcement, the required adhesive force can be obtained and the cover concrete is pressed.

According to the invention of claim 3 , after the PCa plate juxtaposition step, the cover concrete on the open surface of the PCa plate is prevented from being extruded and peeled off by the stress acting on the joint bar . A horizontal U-shaped end with an open end with one open side as the lower end or upper end, and a brittle peeling suppression reinforcing material with the U-shaped end not folded back, is used for the upper end and lower end muscles of multiple joint bars. Of these, since it is arranged on the outer side in the vertical direction on the open surface side and on the inner side of the enlarged diameter portion, in the joint structure of the PCa plate, the padding portion is suppressed while suppressing the brittle fracture form in which the cover concrete is extruded. The width (dimensions) of can be shortened. Therefore, when the present invention is applied to a pier structure, the width of the upper flange of the steel girder of the pier structure can be reduced, and the steel girder of the optimum design according to the strength can be obtained, which is economical. Become. In addition, even when the present invention is applied to the deck of a bridge, the width of the padding is made as narrow as possible to reduce the amount of concrete cast in the field, such as by updating the bridge by half while using (sharing) the bridge. The period can be shortened.

It is a perspective view which shows the pier structure which has the joint structure of the PCa version which concerns on embodiment of this invention. It is a vertical sectional view orthogonal to a steel girder which shows the joint structure of the PCa plate which concerns on embodiment of this invention. It is a vertical sectional view along the steel girder which shows the joint structure of the same above. It is a partially enlarged perspective view which shows the above-mentioned joint structure in the state before placing the stuffed concrete. It is a perspective view which shows the fog peeling suppression reinforcing material which concerns on embodiment of this invention. It is a vertical sectional view orthogonal to a steel girder which shows the joint structure of the conventional PCa deck. It is a vertical cross-sectional view along a steel girder showing the conventional joint structure of the above. It is a process explanatory drawing which shows the PCa plate parallel arrangement process of the method of constructing the joint structure of the PCa plate which concerns on embodiment of this invention. It is a process explanatory drawing which shows the lateral bar arrangement process of the construction method of the said joint structure. It is a process explanatory drawing which shows the reinforcing material arrangement process of the said joint structure construction method. It is a process explanatory drawing which shows the filler filling process of the said joint structure construction method. It is explanatory drawing explaining that the width of the packing part does not shrink in the joint structure of the conventional PCa floor slab.

Hereinafter, an embodiment for implementing the joint structure of the PCa plate according to the present invention and the method for constructing the joint structure will be described in detail with reference to the drawings.

<PCa version joint structure>
First, the joint structure of the PCa plate according to the embodiment of the present invention will be described with reference to FIGS. 1 to 5. A case where the joint structure of the PCa plate according to the present invention is applied to a floor slab constituting a pier structure installed in a harbor or the like will be described as an example.

FIG. 1 is a perspective view showing a pier structure PS having a PCa version joint structure according to an embodiment of the present invention. As shown in FIG. 1, in the pier structure PS according to the illustrated embodiment, a steel girder G is suspended between steel pipe piles P erected at predetermined intervals via a jacket, and a plurality of PCa floors are suspended on the steel girder G. It is a structure in which plates S, ..., S are placed at predetermined intervals to be a filling portion described later. The pier structure PS is installed in a harbor or the like and is used as an artificial ground for a pier of a large cruise ship or the like.

FIG. 2 is a vertical cross-sectional view orthogonal to the steel girder G showing the joint structure 1 of the PCa floor slab (hereinafter, simply referred to as the joint structure 1) which is the joint structure of the PCa plate according to the embodiment of the present invention. Is a vertical cross-sectional view along the steel girder G showing the joint structure 1. Further, FIG. 4 is a partially enlarged perspective view showing a joint structure 1 showing before placing the padded concrete C.

As shown in FIGS. 2 to 4, the joint structure 1 is a structure for connecting and integrating the above-mentioned PCa floor slabs S, and is a space (interval) formed between the PCa floor slabs S. It is a structure applied to the padding portion 2. Filling materials such as concrete C and mortar are placed in the filling portion 2 to integrate the PCa floor slabs S with each other.

In this joint structure 1, the upper end bars S1 and the lower end bars S2 of the main bar of the PCa deck S extend to the stuffing portion 2, and the joint bars 3 and 4 are arranged so as to be orthogonal to these joint bars 3 and 4. It is provided with a plurality of lateral streaks 5 extending over the upper and lower stages and a fog peeling suppressing reinforcing material 6.

The reference numeral SJ is a stud with a head, and the stud SJ with a head is welded to the steel girder G by stud welding, and the steel girder G and the PCa deck S are synthesized by the concrete C of the packing portion 2. , Has a function to integrate.

(Joining bar)
The joint bars 3 and 4 are deformed steel bars (JIS G3112) for reinforced concrete such as SD345 and SD390 in which the main bar of the PCa floor slab S extends outward and protrudes to the filling portion 2. Is. The joint bar 3 is the extension of the upper end bar S1 of the main bar of the PCa deck S, and the joint bar 4 is the extension of the lower end bar S2 of the main bar of the PCa deck S. Of course, the joint bars 3 and 4 are not limited to the deformed reinforcing bars, and other steel materials can be used.

Further, at the ends of these joint bars 3 and 4, a tubular steel material is crimped and fitted around the deformed reinforcing bar as a crimping grip to form enlarged diameter portions 3a and 4a having an expanded diameter of the reinforcing bar. Has been done. In the enlarged diameter portion according to the present invention, a nut or the like may be screwed to the threaded joint reinforcing bar, or the end portion of the reinforcing bar may be expanded in diameter mechanically or by applying heat. In short, in the enlarged diameter portion according to the present invention, the diameter is expanded near the end of the joint bar, and a supporting pressure is applied when the stress acts in the direction in which the joint bar is pulled out from the stuffed concrete C (filler). Any structure may be used.

(Horizontal muscle)
The lateral reinforcing bar 5 is a deformed steel bar for reinforced concrete (JISG3112) such as SD345 and SD390, like the joint reinforcing bars 3 and 4, and the illustrated form is a deformed reinforcing bar having a name of D19.

(Reinforcing material to prevent fogging peeling)
FIG. 5 is a perspective view showing a fog peeling suppressing reinforcing material 6 according to an embodiment of the present invention. The fog peeling suppressing reinforcing material 6 according to the present embodiment is made of a deformed steel bar (JIS G3112) for reinforced concrete of a deformed reinforcing bar having a name D16 or the like. As shown in FIG. 5, the fog peeling suppressing reinforcing material 6 has an upper side 60 and an open end 6a in which one of the lower ends of the four sides having a pair of left and right side sides 61 and 62 is open. It is bent into a shape of.

Of course, the fog peeling suppressing reinforcing material according to the present invention is not limited to steel bars, and may be strip-shaped steel materials. Further, the material is not limited to iron, and new materials such as organic fibers such as polyvinyl alcohol (PVA) fiber, polypropylene fiber, and aramid fiber, and inorganic fibers such as carbon fiber and glass fiber can be used. In short, the peeling suppressing reinforcing material according to the present invention only needs to have the strength required to fulfill the above-mentioned function and the adhesive force with the filler.

As shown in FIGS. 2, 4 and the like, the fog peeling suppressing reinforcing material 6 according to the present embodiment is located near the inside of the enlarged diameter portion 3a on the PCa deck S side and above the joint bar 3 which is the upper end bar. It is installed so that the upper side 60 is placed. The fog peeling suppressing reinforcing material 6 prevents the end portion of the joint bar 3 from rotating upward by the adhesive fixing force of the side sides 61 and 62 to the concrete C, and prevents the end portion of the joint bar 3 from rotating upward by the upper side 60. It has a function to prevent the covered concrete from being extruded and peeled off.

The reason why the upper side 60 of the fog peeling suppressing reinforcing material 6 is installed so as to be placed above the joint bar 3 is that the PCa placed on the steel girder G of the pier structure PS such as the joint structure 1. This is because in the joint structure of the deck S, the stress acting on the joint bar 3 which is the upper end bar on the open surface side becomes dominant in tension. That is, in the joint structure 1 in which the joint bar 3 has a tensile advantage, the enlarged diameter portion 3a rises in an arc by a phenomenon similar to the dowel action, so that the covered concrete of the concrete C on the open surface of the filling portion 2 is covered. However, the force acts in the direction of being pushed out by the joint bar 3.

Therefore, when the stress acting on the joint bar 4, which is usually the lower end bar, has a tensile advantage, such as when the present invention is applied to the deck of a bridge, the fog peeling suppressing reinforcing material 6 is turned upside down from the illustrated form. It is necessary to install in the state of.

Further, the reason why the fog peeling suppressing reinforcing material 6 is installed near the inside of the enlarged diameter portion 3a is that in order to prevent the enlarged diameter portion 3a from rising in an arc, the principle of leverage is used. This is because it is advantageous to install it near the tip of the joint bar 3. This is because by arranging the fog peeling suppressing reinforcing material 6 inside the enlarged diameter portion 3a, the upper side 60 of the fog peeling suppressing reinforcing material 6 is hooked by the enlarged diameter portion 3a.

In short, the fog peeling suppressing reinforcing material according to the present invention is arranged on the outer side in the vertical direction on the open surface side of the joint bars 3 and 4 on which the tensile force acts, and on the inner side of the enlarged diameter portions 3a and 4a. It suffices if it has been done.

In the joint structure 1 according to the present embodiment, since it is a pier structure PS, the plate thickness of the PCa deck S is usually 300 mm or more. Therefore, as in the fog peeling suppressing reinforcing material 6 according to the present embodiment, the required adhesion fixing force can be secured only by the lengths of the pair of left and right linear side sides 61 and 62. However, when the plate thickness of the PCa deck S is usually thin, such as when the present invention is applied to the deck of a bridge, a hairpin hook bent by 135 degrees or more is provided at the open end 6a to provide necessary adhesion fixing force. It is preferable to provide appropriate means for ensuring.

Further, as another means for securing the adhesion fixing force required when the fixing length is insufficient only by the linear length, an enlarged portion whose cross section is enlarged to the open end 6a of the fog peeling suppressing reinforcing material 6 ( (Not shown) is conceivable. According to this means, since the reinforcement work of the fog peeling suppressing reinforcing material 6 is only inserted from above or below, the workability is extremely good as compared with the case where a hairpin hook or the like is provided.

<Effects of PCa version joint structure>
Next, with reference to FIGS. 6 and 7, the operation and effect of the above-mentioned joint structure 1 will be described in comparison with the joint structure of the PCa deck of the conventional pier structure. FIG. 6 is a vertical cross-sectional view orthogonal to the steel girder G showing the joint structure 1'of the conventional PCa deck, and FIG. 7 is a vertical cross-sectional view along the steel girder G showing the joint structure 1'.

In this joint structure 1', the upper end bars S1'and the lower end bars S2'of the main bar of the PCa deck S'extend to the stuffing portion 2', and these joint bars 3', 4', It is provided with a plurality of lateral bars 5'over the upper and lower stages arranged so as to be orthogonal to 4'. Further, concrete C is placed in the stuffing portion 2'to integrate the PCa floor slabs S'.

Then, similarly to the above-mentioned joint structure 1, a tubular steel material is caulked and fitted around the deformed reinforcing bars as a crimping grip at the ends of these joint bars 3'and 4', and the diameter of the reinforcing bars is expanded. The expanded diameter portions 3a'and 4a' are formed.

Here, as shown in FIG. 6, the required joint length L'of the joint structure 1'is required to be 15 times or more the nominal diameter of the reinforcing bar, as described in the background art. In the illustrated form, since the joint bars 3'and 4'are the deformed reinforcing bars of D19, 15φ = 285 mm is required.

On the other hand, as shown in FIG. 2, the required joint length L of the joint structure 1 can be 10 times or less the nominal diameter of the reinforcing bar, that is, 10φ = 190 mm. According to the joint structure 1, the fog peeling suppressing reinforcing material 6 causes the enlarged diameter portion 3a to rise in an arc by a phenomenon similar to the dowel action, and the fog on the open upper surface of the concrete C of the filling portion 2. This is because it is possible to prevent the concrete from being extruded by the joint bar 3.

That is, according to the joint structure 1 according to the present embodiment, the width (dimensions) of the padded portion can be shortened while suppressing the brittle fracture mode in which the cover concrete is peeled off. Therefore, the width of the upper flange of the steel girder G of the pier structure PS can be made smaller than the width of the conventional steel girder G', and the pier structure PS can be optimally designed according to the strength, which is economical. Will be.

<How to build a PCa version joint structure>
Next, a method of constructing the joint structure of the PCa plate according to the embodiment of the present invention will be described with reference to FIGS. 8 to 11. The case of constructing the above-mentioned joint structure 1 will be described as an example. Hereinafter, the method for constructing the joint structure of the PCa version according to the embodiment of the present invention is simply referred to as the method for constructing the joint structure 1.

(1) PCa plate parallel installation process First, as shown in FIG. 8, in the method of constructing the joint structure 1 according to the present embodiment, the joint bars 3 and 4 in which the enlarged diameter portions 3a and 4a are formed at the above-mentioned end portions. A PCa slab side-by-side step is performed in which a plurality of PCa floor slabs S having the above are arranged side by side at predetermined intervals.

Specifically, the PCa deck S is lifted using a lifting machine such as a crane, and placed on the steel girder G of the pier structure PS at predetermined intervals.

(2) Lateral Reinforcement Reinforcement Step Next, in the method of constructing the joint structure 1 according to the present embodiment, a lateral reinforcement reinforcement step of arranging the lateral reinforcement 5 of the stuffing portion 2 at a predetermined position is performed. ..

Specifically, as shown in FIG. 9, a plurality of lateral bars 5 are arranged at predetermined positions at a predetermined pitch, and joints are joined with a binding wire or the like so as not to move when the concrete C is placed. Bind and fix to muscles 3 and 4.

In addition, when transporting the lateral bars 5, the required number of streaks 5 are collectively fixed in the space above the precast concrete step portion of the PCa deck S, and transported together with the PCa deck S by a lifting machine in the previous process. preferable. This is because the lateral bar 5 which is long, heavy, and difficult to be transported by human power can be safely and easily transported, and the time required for transportation can be shortened.

(3) Reinforcing Material Arrangement Step Next, in the method for constructing the joint structure 1 according to the present embodiment, the above-mentioned cover peeling suppressing reinforcing material 6 is placed on the joint reinforcement 3 which is the upper end reinforcement arranged on the open upper surface side. A reinforcing material arranging step is performed on the upper side and inside the enlarged diameter portion 3a.

Specifically, as shown in FIG. 10, the upper side 60 is placed so as to be placed above the joint bar 3 which is the upper end bar, in the immediate vicinity of the inside of the enlarged diameter portion 3a on the PCa deck S side. The concrete C is bound and fixed to the joint bars 3 and 4 with a binding wire or the like so as not to move when the concrete C is placed. Further, as shown in FIG. 4 and the like, the enlarged diameter portion 3a of the PCa floor slab S on the left side of the figure is also bound and fixed in the same manner. At this time, the fog peeling suppressing reinforcing members 6 are fixed so as to be arranged alternately so as not to have a strong weak point.

It is preferable that the cover peeling suppressing reinforcing material 6 is also carried by a lifting machine together with the PCa deck S, similarly to the lateral bar 5.

The (2) lateral bar arrangement step and (3) reinforcing material placement step may be performed in parallel, or the reinforcing material placement step may be performed prior to the lateral bar arrangement step. ..

At this time, as described above, the shape of the fog peeling suppressing reinforcing material 6 is a horizontal U-shape having an open end 6a having an upper side 60 and side sides 61 and 62 with an open lower end. Therefore, even in the filling portion 2 having a small gap in which the joint bars 3 and 4 and the lateral bars 5 are crowded, the joint bars 3 and 4 can be easily arranged by simply pointing from above.

Therefore, the work time of the reinforcing material arranging process and the lateral bar arrangement process, and by extension, the work time of the construction work of the joint structure 1 can be shortened, and the installation cost can be reduced.

(4) Filler Filling Step Next, in the method for constructing the joint structure 1 according to the present embodiment, a filler filling step of filling the filling portion 2 with the filler is performed.

Specifically, as shown in FIG. 11, concrete C is cast and filled in the filling portion 2 as a filler. Of course, the filler to be filled in the filling portion 2 is not limited to concrete, and although the cost is high, it is also possible to use mortar or other time-curing material that cures after a certain period of time, depending on the application.

After that, when a predetermined curing period in which the concrete C develops a predetermined strength elapses, the PCa decks S and the steel girder G of the pier structure PS and the PCa deck are solidified and integrated. As a result, all the work steps of the method for constructing the joint structure 1 according to the present embodiment are completed.

According to the method for constructing the joint structure 1 according to the present embodiment, as described above, in the joint structure 1 of the PCa deck, while suppressing the brittle fracture form in which the cover concrete of the filling portion 2 is extruded, the space is maintained. The width (dimensions) of the packing portion 2 can be shortened. Further, since the width of the filling portion 2 is narrowed, the amount of concrete C placed can be reduced, and not only the material cost can be reduced, but also the installation cost can be reduced by shortening the working time.

The joint structure of the PCa version and the method of constructing the joint structure according to the embodiment of the present invention have been described in detail above. However, none of the above-mentioned or illustrated embodiments shows only one embodiment embodied in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. It is a thing.

In particular, although it has been described that the PCa version is applied to a pier structure as an example, the present invention can also be applied to a PCa floor slab of a bridge. Even in that case, it is clear that the width (dimensions) of the packed portion can be shortened while suppressing the brittle fracture form in which the cover concrete is extruded. Therefore, when the present invention is applied to the floor slab of a bridge, the width of the padded portion can be narrowed as much as possible to reduce the amount of concrete cast on site and shorten the construction period, while using (sharing) the bridge. It is extremely useful when updating one half at a time.

Further, although the PCa floor slab has been exemplified and described as the PCa plate, the present invention can be applied to the joint structure between the PCa plates. Even in that case, it is clear that the width (dimensions) of the packed portion can be shortened while suppressing the brittle fracture form in which the cover concrete of the joint portion is extruded.

PS: Pier structure P: Steel pipe pile G, G': Steel girder SJ: Stud with head (stud gibber)
S, S': PCa floor version (PCa version)
S1, S1': Upper end bar S2, S2': Lower end bar 1: PCa floor slab joint structure (PCa version joint structure)
1': Joint structure of conventional PCa floor slabs 2, 2': Filling portions 3, 3', 4, 4': Joint bars 3a, 3a', 4a, 4a': Enlarged diameter portions 5, 5': Horizontal Directional bar 6: Fogging peeling suppression reinforcing material 6a: Open end 60: Upper side 61, 62: Side side C: Concrete (filler)

Claims (3)

It is a PCa plate joint structure in which concrete is poured and integrated at the packing part that connects the PCa plates.
A plurality of joint bars extending over the upper and lower stages where the upper end bar and the lower end bar of the main bar of the PCa plate extend to the padding portion, and
The stuffing portion is provided with a plurality of lateral bars arranged in the upper and lower stages so as to be orthogonal to the plurality of joint bars.
An enlarged diameter portion is formed at each end of the plurality of joint bars, and an enlarged diameter portion is formed.
Of the upper end and lower end bars of the plurality of joint bars, the cover peeling inhibitor that prevents the cover concrete on the open surface of the PCa plate from being extruded and peeled by the stress acting on the joint bars is said. It is arranged on the outside in the vertical direction on the open surface side and inside the enlarged diameter portion .
The fog peeling suppressing reinforcing material is characterized in that it has a horizontal U-shape with an open end having one of the four sides open as the lower end or the upper end, and the U-shaped end is not folded back . PCa version joint structure. The PCa plate joint structure according to claim 1 , wherein an enlarged portion having an enlarged cross section of the fog peeling suppressing reinforcing material is formed at the open end. It is a method of constructing a joint structure of the PCa plate in which concrete is poured and integrated in the packing part connecting the PCa plates.
PCa plates having a plurality of joint bars in which the upper end bar and the lower end bar of the main bar extend outward and an enlarged diameter portion is formed at the end portion are arranged at predetermined intervals to serve as the padding portion. PCa version parallel installation process to be installed and
After the PCa plate parallel installation step , one of the four sides is an open end that prevents the cover concrete on the open surface of the stuffing portion from being extruded and peeled off by the stress acting on the joint bar. A horizontal U-shaped end with the lower end or the upper end, and the U-shaped end is not folded back . A method for constructing a PCa plate joint structure, which comprises a reinforcing material arranging step of arranging the surface side in the vertical direction outside and inside the enlarged diameter portion.

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