JP6845457B1 - How to replace concrete bridges with precast floor slabs - Google Patents

Abstract

PROBLEM TO BE SOLVED: To replace a concrete bridge with a precast floor slab capable of effectively fixing a tensile resistance material such as a stirrup of an existing main girder and integrating a newly installed precast floor slab with an existing main girder. Provide a method. SOLUTION: In a method of replacing an RC slab of a concrete bridge with a precast slab of a concrete bridge, the upper part of a main girder to be joined to the RC slab of a concrete bridge is scraped off and a stirrup or the like is used. The upper part of the tensile resistance material is exposed, the exposed tensile resistance material is cut in the middle and effectively fixed by the mechanical fixing means, and then the slip prevention means is connected to the mechanical fixing means to make a box punching hole. The precast floor slab having the above is placed on the main girder, the slip prevention means is housed in the box punching hole, the filler is filled and cured, and the precast floor slab and the main girder are integrated. To become. [Selection diagram] FIG. 12

Description

The present invention relates to a replacement method for replacing a cast-in-place RC slab of a concrete bridge with a precast slab.

In bridges such as road bridges, concrete slabs are damaged by repeated wheel loads due to vehicle traffic, so after a certain period of time, the damaged old RC slabs are removed from the bridge girders and replaced with new slabs. It is being replaced and updated. In recent years, new floor slabs have been updated to precast floor slabs. This is because the precast floor slab is manufactured in a factory or the like where the surrounding environment is prepared, so that a high-quality product can be stably supplied and the renewal work period can be shortened.

For example, Patent Document 1 discloses a method for replacing a precast floor slab for a PC synthetic girder, which replaces a cast-in-place RC floor slab of a concrete bridge of a T-type synthetic girder with a precast floor slab for a PC synthetic girder (Patent Document 1). 1), paragraphs [0034] to [0041] of the specification, FIGS. 5 to 14 of the drawings, and the like).

However, in the method for replacing the precast water slab for PC synthetic girder described in Patent Document 1, the slip-preventing reinforcing bar 12 and the stirrup 13 of the main girder 3 are used at the joint portion of the integrated synthetic girder with the RC water slab. Since it is necessary to leave it, a large amount of concrete must be scraped with ultra-high pressure water such as a breaker or a water jet, which causes a problem that it takes a long time to work.

Further, in the method of replacing the precast floor slab for PC composite girder described in Patent Document 1, in order to leave the anti-slip reinforcing bar 12 and the stirrup 13 arranged on the main girder, the steel plate embedded in the precast floor slab is used. There is a problem that it is difficult to install the precast floor slab in an appropriate position or it takes time to install it because the reinforcing bars interfere with each other.

In addition, in the method for replacing the precast floor slab for PC synthetic girders described in Patent Document 1, a space for fixing the anti-slip reinforcing bars 12 and the stirrup 13 under the precast floor slab for PC synthetic girders and the upper part of the space. Since the floor slab thickness for arranging the horizontal tightening PC steel material is required, the thickness of the floor slab after renewal becomes thicker than before renewal, and there is a problem that the remaining main girder and substructure are burdened. There was also.

In order to solve such a problem, it is conceivable to cut the anti-slip reinforcing bar or the stirrup in the middle. However, according to the idea of the road specification, the stirrup, which is a tensile resistance material for synthetic girders, must be designed based on the truss theory, and the load-bearing mechanism cannot be established unless it is fixed to the compressed chord material, and the main girder. There is a problem that the web part of is not functioning effectively. Therefore, when such a problem is solved and the RC floor slab of a concrete bridge made of synthetic girders is replaced with a precast floor slab, the cut stirrup is effectively fixed and the RC floor slab is replaced with a precast floor slab. There was a longing for a way to update to.

In addition, when the synthetic floor slab is replaced with a precast floor slab, a method for integrating the precast floor slab and the main girder has been established. The cross section could not be valid.

Japanese Unexamined Patent Publication No. 2019-132070

Therefore, the present invention has been devised in view of the above-mentioned problems, and an object of the present invention is to effectively fix an existing tensile resistance material such as a stirrup of a main girder and to newly install a precast floor. The purpose is to provide a method of replacing a concrete bridge with a precast slab that can integrate the slab with an existing main girder.

The method of replacing the RC slab of a concrete bridge with a precast slab according to the first invention is a method of replacing the RC slab of a concrete bridge with a precast slab of a concrete bridge, and is a method of replacing the RC floor of a concrete bridge with a precast slab. The upper part of the main girder to be joined to the plate is scraped off to expose the upper part of the tensile resistance material made of reinforcing bars , and the exposed tensile resistance material is cut in the middle to cut the mechanical fixing means into the tensile resistance material. After fixing and fixing the tensile resistance material so that it does not shift in the material axial direction, a slip prevention means is connected to the mechanical fixing means, and a precast floor slab having a box punching hole is placed on the main girder. It is characterized in that the precast floor slab and the main girder are integrated by accommodating the slip prevention means in the box punching hole, filling the filler and curing the concrete.

The method for replacing a concrete bridge with a precast slab according to the second invention is, in the first invention, the slip prevention means connected to the mechanical fixing means after the precast slab is placed on the main girder. The head of the concrete is configured to be retrofitted to the shaft portion, and the precast floor slab is placed on the main girder, and then the head of the slip prevention means is attached to the shaft portion. ..

The method for replacing a concrete bridge with a precast slab according to the third invention is the method of replacing the concrete bridge with a precast slab. In the first invention, the slip prevention means connected to the mechanical fixing means is configured to be retrofitted to the mechanical fixing means. The precast floor slab is placed on the main girder, and then the slip prevention means is connected to the mechanical fixing means.

The method for replacing the concrete bridge with the precast slab according to the fourth invention is that in any one of the first to third inventions, the slip prevention means is connected to the mechanical fixing means. A post-construction anchor connected to the main girder is also used, and before the precast floor slab is placed on the main girder, a post-construction anchor is installed on the upper surface of the main girder to provide a slip prevention means. It is characterized in that it is fixed to the main girder.

In the method of replacing the concrete bridge with the precast floor slab according to the fifth invention, in any one of the first to fourth inventions, the reinforcing bars of the precast floor slab are exposed in the box punching hole. It is characterized by being.

The method for replacing a concrete bridge with a precast floor slab according to the sixth invention is as follows, in the fifth invention, the exposed reinforcing bars are joined by a screw type mechanical joint so as to be removable. After the floor slab is placed on the main girder, the exposed reinforcing bars are attached to the box punching holes.

The method for replacing a concrete bridge with a precast slab according to the seventh invention is characterized in that, in the first invention, the slip prevention means is a headed stud.

According to the first to seventh inventions, a high-quality precast slab is newly installed to replace an old and damaged existing RC slab by effectively fixing a tensile resistance material such as a stirrup of a main girder of a concrete bridge. Can be replaced with. Therefore, the existing concrete bridge can be renewed at low cost and in a short period of time, and the existing concrete bridge can be appropriately maintained to achieve a long life.

Further, according to the first to seventh inventions, the newly installed precast floor slab and the existing main girder can be integrated, and the synthetic cross section including the precast floor slab can counter the external force. The thickness of the floor slab can be reduced to extend the life and durability of the existing main girder.

In particular, according to the second and third inventions, the head of the slip-preventing means having a large diameter can be retrofitted, and it is easy to place the precast floor slab on the main girder even if there is a dimensional error. Become.

In particular, according to the fourth invention, it is possible to add anti-slip means to the main girder with a post-construction anchor, and it becomes easy to secure the required number of anti-slip means.

In particular, according to the fifth invention, it is possible to install a slip-preventing means continuous with a tensile resistance material such as a stirrup in the vicinity of a reinforcing reinforcing bar penetrating a box punching hole of a newly installed precast floor slab, and the existing main The girder can be firmly integrated with the newly installed precast floor slab.

In particular, according to the sixth invention, there is a situation in which the precast floor slab cannot be placed on the main girder due to the interference between the reinforcing bar penetrating the box punching hole and the continuous slip-preventing means of the tensile resistance material due to the dimensional error. Can be prevented.

In particular, according to the seventh invention, a headed stud having a proven track record in integrating a steel girder with a precast floor slab can achieve integration between an existing main girder and a newly installed precast floor slab. More safety and reliability.

FIG. 1 is a vertical cross-sectional view showing a state in which a bridge to which a method for replacing a concrete bridge according to an embodiment of the present invention is replaced with a precast slab is vertically cut in a direction perpendicular to the bridge axis. FIG. 2 is an enlarged view of part A of FIG. FIG. 3 is a process explanatory view showing the step of removing the floor slab of the method of replacing the concrete bridge with the precast floor slab according to the embodiment of the present invention in an overall cross-sectional view cut along the direction Y perpendicular to the bridge axis. FIG. 4 is a process explanatory view showing an enlarged cross-sectional view of the main girder upper chipping step of the method of replacing the concrete bridge with the precast floor slab according to the embodiment of the present invention. It shows before the main girder upper chipping process, and (b) shows after the main girder upper chipping process. FIG. 5 is a process explanatory view showing an enlarged cross-sectional view of a portion B of FIG. 4 showing a non-landing adjustment step of a method of replacing a concrete bridge with a precast slab according to an embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view showing a tensile resistance material fixing step of a method for replacing a concrete bridge with a precast floor slab according to an embodiment of the present invention. FIG. 7 is a process explanatory view showing a case where the tensile resistance material fixing step is performed by using the mechanical fixing means according to the second embodiment. FIG. 8 is a process explanatory view showing a case where the tensile resistance material fixing step is performed by using the mechanical fixing means according to the third embodiment. FIG. 9 is an enlarged cross-sectional view showing a step of connecting a slip-preventing means of a method of replacing a concrete bridge with a precast slab according to an embodiment of the present invention. FIG. 10 is an enlarged cross-sectional view showing a slip-preventing means according to a modified example of connecting in a slip-preventing means connecting step of a method of replacing a concrete bridge with a precast floor slab according to an embodiment of the present invention. FIG. 11 is an enlarged cross-sectional view showing a step of adding a slip-preventing means of a method of replacing a concrete bridge with a precast slab according to an embodiment of the present invention. FIG. 12 is a process explanatory view showing an overall cross-sectional view of the precast slab mounting step of the method for replacing the concrete bridge with the precast slab according to the embodiment of the present invention, cut along the direction Y perpendicular to the bridge axis. is there. FIG. 13 is a process explanatory view showing a step of placing the precast floor slab in the method of replacing the concrete bridge with the precast floor slab according to the embodiment of the present invention in a plan view. FIG. 14 is a partially enlarged plan view showing another example of the box punching hole 50 of the precast floor slab 5 to be mounted in the same precast floor slab mounting step. 15A and 15B are process explanatory views when the present invention is applied to a box girder bridge, in which FIG. 15A shows before updating, FIG. 15B shows when the floor slab is removed, and FIG. 15C shows after updating. FIG. 16 is a process explanatory view when the present invention is applied to a floor slab bridge of a hollow floor slab (hollow slab), where (a) is before renewal, (b) is when the floor slab is removed, and (c) is after renewal. Is shown.

Hereinafter, an embodiment for implementing a method for replacing a concrete bridge according to the present invention with a precast slab will be described in detail with reference to the drawings.

A method of replacing a concrete bridge with a precast slab according to an embodiment of the present invention will be described with reference to FIGS. 1 to 16. A T-girder bridge will be described as an example of a bridge to which the method of replacing the concrete bridge according to the embodiment of the present invention with a precast slab is applied.

<Bridge>
First, with reference to FIGS. 1 and 2, a bridge to which the method of replacing the concrete bridge according to the embodiment of the present invention with a precast slab is applied will be briefly described. FIG. 1 is a vertical cross-sectional view showing a state in which a bridge to which the method for replacing a concrete bridge according to an embodiment of the present invention is replaced with a precast slab is vertically cut in a direction perpendicular to the bridge axis, and FIG. 2 is a vertical cross-sectional view. It is an enlarged view of the part A of FIG.

The bridge B1 to which the present invention is applied is a reinforced concrete (RC) bridge used as a road bridge, and includes four reinforced concrete (prestressed concrete main girders) as shown in FIGS. 1 and 2. It is composed of T girders G1 to G4, which are the main girders of (the same applies hereinafter), and a cast-in-place RC slab F1 which is a synthetic slab joined to the upper parts of these T girders G1 to G4. Further, along the edges on both sides of the RC floor slab F1, a wall balustrade W1 and a ground covering portion W2 are formed as a bollard. However, facilities and asphalt pavement installed above the wall balustrade W1 and the ground cover W2 are not necessarily installed, so they are omitted.

The X direction in the figure refers to the bridge axis direction along the axial directions of the T girders G1 to G4 of the bridge B1, and the Y direction is the horizontal direction perpendicular to the bridge axis direction X of the bridge B1. Is pointing to. Further, the Z direction refers to the vertical direction, which is the vertical direction.

Further, as shown in FIG. 2, the stirrup Sr, which is a tensile resistance material of the T girder G2 (G1, G3, G4), has an upper portion extending to the RC floor slab F1 to secure a fixing length with a hook and RC. It is fixed in the upper part F1a of the main girder of the floor slab F1. Further, a U-shaped slip-preventing reinforcing bar S1 is arranged on the upper part F1a of the main girder to be joined to the T girder G2 of the bridge B1. Then, oblique streaks S2 continuous up to the T girder G2 are arranged on the haunch portion of the RC floor slab F1. In this way, the bridge B1 is a site-made synthetic girder bridge in which the T girder G2 and the RC floor slab F1 are integrated to counter external forces.

Next, a specific procedure of the method of replacing the concrete bridge with the precast slab according to the embodiment of the present invention will be described with reference to FIGS. 3 to 9.

(Floor slab removal process)
FIG. 3 is a process explanatory view showing the step of removing the floor slab of the method of replacing the concrete bridge with the precast floor slab according to the embodiment of the present invention in an overall cross-sectional view cut along the direction Y perpendicular to the bridge axis. First, in the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, as shown in FIG. 3, a floor slab removing step of cutting and removing the RC floor slab F1 is performed.

Specifically, using a large rotary cutting device called a wall saw or a diamond cutter, the RC slab F1 beside the T girders G1 to G4 indicated by ▽ in the figure is cut along the bridge axis direction X. , RC floor slab F1 is cut along the direction Y perpendicular to the bridge axis, and RC floor slab F1 is subdivided. After that, the RC floor slab F1 that has been lifted by a lifting machine such as a crane and divided into small pieces is carried out, and concrete is crushed and dismantled and removed using a breaker or the like at another place.

(Main girder upper part chipping process)
FIG. 4 is a process explanatory view showing an enlarged cross-sectional view of the main girder upper chipping step of the method of replacing the concrete bridge with the precast floor slab according to the embodiment of the present invention. It shows before the main girder upper chipping process, and (b) shows after the main girder upper chipping process. Next, in the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, as shown in FIG. 4, the girder upper part scraping step of scraping the main girder upper part F1a of the RC floor slab F1 of the bridge B1 is performed. Do.

Specifically, using a chipping device such as a water jet, the concrete of the upper part F1a of the main girder, which is the remainder of the RC floor slab F1 removed in the front floor slab removal process other than the T girders G1 to G4, is scraped off. , Also cut and remove the internal reinforcing bars. However, as shown in FIG. 4, the stirrup Sr is exposed by leaving the upper portion for a predetermined length (about 50 mm to 100 mm in the embodiment) required for attaching the mechanical fixing means described later, and the rest is removed. Remove it together with other internal reinforcing bars that interfere with the replacement work.

The end faces exposed to the outside after cutting of the slip prevention reinforcing bars S1 and the oblique bars S2 are subjected to rust preventive end face treatment such as applying a rust preventive resin.

Further, since the tensile resistance material in the truss theory is not continuous at this point, the T girder G2 (G1, G3, G4) shown in FIG. 4 is not used for shearing and twisting, instead of the composite cross section including the precast floor slab 5 described later. ) Is checked in cross section. After being integrated with the precast floor slab 5 through the slip prevention means connection step described later, the tensile resistance material in the truss theory is continuous, so the composite cross section is checked. If the strength is insufficient in calculation, the carbon fiber is bonded to the outer surface of the web portion of the T girder G2. In addition, prestress may be introduced as appropriate.

(Non-land adjustment process)
FIG. 5 is a process explanatory view showing an enlarged cross-sectional view of a portion B of FIG. 4 showing a non-landing adjustment step of a method of replacing a concrete bridge with a precast slab according to an embodiment of the present invention. Next, in the method of replacing the concrete bridge with the precast slab according to the present embodiment, as shown in FIG. 5, the upper surface of the T girders G1 to G4 is smoothed by the non-landing adjusting material P. Perform a non-land adjustment process.

Specifically, the upper surface of the T-girder G2, which has been scraped off in the upper part of the front main girder to form irregularities, is cleaned, a primer for concrete is applied, and at least around the exposed stirrup Sr. A putty-like non-landing adjusting material P is applied to the upper surfaces of the T-girders G1 to G4 to adjust the non-landing so as to be smooth.

Examples of the primer include an epoxy-based primer, an acrylic-based primer, and a urethane-based primer. Further, examples of the non-landing adjusting material P include inorganic type, organic type (for example, epoxy type, acrylic type, urea type, urethane type), resin mortar and the like. However, the non-landing adjusting material used in the present invention can be applied as long as it has a predetermined viscosity and is in the form of a putty that can be adhered to concrete via a primer.

Further, in this step, not only the periphery of the stirrup Sr but also the entire upper surface of the T girders G1 to G4 may be smoothed. This is because the precast floor slab installation process, which is a post-process, can be easily executed. However, this step may not be carried out, and the next step may be carried out suddenly. This is because the stirrup Sr can be fixed by executing the next process without adjusting the land.

(Tensile resistance material fixing process)
FIG. 6 is an enlarged cross-sectional view showing a tensile resistance material fixing step of a method for replacing a concrete bridge with a precast floor slab according to an embodiment of the present invention. Next, in the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, the mechanical fixing means 1 according to the first embodiment shown in FIG. 6 is fixed to the stirrup Sr which is a tensile resistance material. A tensile resistance material fixing step is performed in which the tensile resistance material is fixed so as not to shift in the material axial direction.

Specifically, as shown in FIG. 6, a cylindrical steel material P1 is externally fitted to the exposed portion on the main girder of the T girders G1 to G4 of the stirrup Sr left in the upper cutting process of the front main girder, and a hydraulic device or the like is used. Crimping and crimping. That is, the mechanical fixing means 1 according to the first embodiment is a steel pipe crimping type reinforcing bar fixing means for crimping a cylindrical steel material P1 to a deformed steel rod (reinforcing bar) which is a tensile resistance material. Of course, the steel material to be crimped is not limited to a cylindrical shape, and may be a polygonal tubular body such as a nut or a square tubular steel material.

Next, a case where the tensile resistance material fixing step is performed by using the mechanical fixing means 2 according to the second embodiment different from the embodiment of FIG. 6 will be described. FIG. 7 is a process explanatory view showing a case where the tensile resistance material fixing step is performed by using the mechanical fixing means according to the second embodiment. As shown in FIG. 7, in this step, the cylindrical steel material P2 is externally fitted to the exposed portion on the main girder of the T girders G1 to G4 of the stirrup Sr left in the front main girder upper part scraping step to form the cylindrical steel material P2. Drive the wedge K1 into the gap between the stirrup Sr and fix it. That is, the mechanical fixing means 2 according to the second embodiment is a wedge fixing type reinforcing bar fixing means for fixing a cylindrical steel material P2 to a deformed steel rod (reinforcing bar) which is a tensile resistance material by using a wedge K1.

Next, a case where the tensile resistance material fixing step is performed by using the mechanical fixing means 3 according to the third embodiment will be described. FIG. 8 is a process explanatory view showing a case where the tensile resistance material fixing step is performed by using the mechanical fixing means according to the third embodiment. As shown in FIG. 8, in this step, a thread groove is cut on the outer peripheral surface of the exposed portion on the main girder of the T girders G1 to G4 of the stirrup Sr left in the step of scraping the upper part of the front main girder, and the thread groove is formed. The long nut P3 to be screwed is screwed. That is, the mechanical fixing means 3 according to the third embodiment is a screw fixing type reinforcing bar fixing means for screwing a long nut P3 into a deformed steel rod (reinforcing bar) which is a tensile resistance material. Of course, the shape of the long nut is not particularly limited, and a tubular body having a thread thread screwed with the thread groove cut on the inner peripheral surface can be formed.

Although the mechanical fixing means 1 to 3 according to the first to third embodiments have been exemplified and described above as the fixing means of the stirrup Sr which is a tensile resistance material, other mechanical fixing means applicable to the present invention have been described above. As the means, a mechanical fixing means in which a tubular steel material is externally fitted into a stirrup and a filler made of a time-curing material is filled and cured in the meantime to be fixed, or these mechanical fixing means 1 to 3 and a filler are used. It can also be used as a mechanical fixing means in combination with the above. As the filler made of the time-curing material, an inorganic type, an organic type (for example, an epoxy type, an acrylic type, a urea type, a urethane type), a resin mortar, or the like is adopted as in the case of the non-landing adjusting material P described above. can do.

In short, the mechanical fixing means applicable to the present invention has a portion larger than the diameter of the steel material, and the fixing body that enhances the adhesive force with the concrete against the tensile force acting in the axial direction of the steel material is firmly formed. Any fixed mechanical fixing may be used.

(Slip prevention means connection process)
FIG. 9 is an enlarged cross-sectional view showing a step of connecting a slip-preventing means of a method of replacing a concrete bridge with a precast slab according to an embodiment of the present invention. Next, in the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, the slip prevention means for connecting the stud portion to the mechanical fixing means 1 and 3 fixed to the stirrup Sr in the front tensile resistance material fixing step. Perform the connection process.

Specifically, as shown in FIG. 9, in parallel with the tensile resistance material fixing process, the stirrup Sr T girders G1 to G4 left on the upper girder of the front main girder are prevented from slipping on the exposed portion on the main girder. The cylindrical steel material P4 to which the means Z1 is connected is fitted externally and crimped by a hydraulic device or the like.

As shown in FIG. 9, in the illustrated embodiment, the slip prevention means Z1 is a headed stud SJ (stud gibber), and the headed stud SJ can be retrofitted (removably) to the cylindrical steel material P4. It is matched.

In this way, the headed stud SJ as the slip prevention means Z1 is a headed stud that has a proven track record of integrating with the precast floor slab with the steel girder, and the existing main girders G1 to G4 and the newly installed precast floor slab. Integration with 5 can be achieved, and safety and reliability are further improved.

FIG. 10 is an enlarged cross-sectional view showing a slip-preventing means Z2 according to a modified example of connecting in a slip-preventing means connecting step of a method of replacing a concrete bridge with a precast floor slab according to an embodiment of the present invention. As shown in FIG. 10, the slip-preventing means Z2 according to the modified example may have a configuration in which the head portion Sh is screwed to the shaft portion Sb made of a screwed steel rod fixed to the cylindrical steel material P5 so as to be retrofitted. Absent. In this way, by making the head Sh removable and retrofittable, it is possible to install a large-diameter head Sh between the narrow exposed reinforcing bars 51 described later.

Of course, the long nut P3 of the mechanical fixing means 3 may be screwed into the slip-preventing means Z1 or the slip-preventing means Z2 according to the modified example may be fixed to the long nut P3.

(Slip prevention means expansion process)
FIG. 11 is an enlarged cross-sectional view showing a step of adding a slip-preventing means of a method of replacing a concrete bridge with a precast slab according to an embodiment of the present invention. Next, in the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, a post-construction anchor is installed on the upper surface of the main girder to perform a slip prevention means expansion step of fixing the slip prevention means to the main girder.

This step is performed when the slip prevention means Z1 (Z2) connected to the tensile resistance material such as Stirrup Sr is insufficient to provide the slip prevention means necessary for integration with the precast floor slab 5. Specifically, a hole for an anchor is drilled on the upper surface of the T girders G1 to 4 which are the main girders with a drilling machine, a post-construction anchor 7 is placed, and a stud bolt SJ'which is a slip prevention means Z3 is installed. Fixed to T digits G1 to G4. As shown in FIG. 11, the stud bolt SJ'is arranged side by side in the slip prevention means Z1 connected to the tensile resistance material so as to be housed together in the box punching hole described later.

The post-construction anchor is preferably an inorganic adhesive anchor in which an activating liquid made into an inorganic cement-based main agent paste is contained in a glass tube container at a constant ratio. This is because the inorganic adhesive anchor does not contain a volatile organic compound (VOC) as a raw material and can exhibit a predetermined strength regardless of the ambient temperature environment. Of course, it goes without saying that other post-construction anchors such as mechanical type may be used for construction.

(Precast floor slab placement process)
FIG. 12 is a process explanatory view showing an overall cross-sectional view of the precast slab mounting step of the method for replacing the concrete bridge with the precast slab according to the embodiment of the present invention, cut along the direction Y perpendicular to the bridge axis. FIG. 13 is a process explanatory view showing a plan view of the precast floor slab mounting process of the method for replacing the concrete bridge with the precast floor slab according to the embodiment of the present invention. Further, FIG. 14 is a partially enlarged plan view showing another example of the box punching hole 50 of the precast floor slab 5 to be placed in the precast floor slab placing step. Next, in the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, the precast floor slab placing step of placing the precast floor slab on the main girder is performed.

The precast floor slab 5 used in this step is provided with a box punching hole 50 in order to integrate with the slip prevention means Z1 described above. As shown in FIG. 12, the box punching hole 50 is a through hole that penetrates the precast floor slab 5 up and down, and is upward so that the slip stopper portion is not pulled out by the bending stress acting on the precast floor slab 5. A taper that expands as it goes is formed. However, in some cases, the box punching hole 50 may be a hole whose upper surface is closed.

Further, as shown in FIG. 14, in the box punching hole 50, a part of the reinforcing bars which are the main reinforcing bars of the upper end reinforcing bar and the lower end reinforcing bar of the precast floor slab 5 is exposed in the hole as the exposed reinforcing bar 51. This is because the axial reinforcing bars and the reinforcing bars orthogonal to the axial reinforcing bars are arranged as close as possible to the slip prevention means Z1 continuous with the stirrup Sr based on the truss theory.

Specifically, in this step, a lifting machine such as a crane is used to place the precast floor slab 5 on the T girders G1 to G4 so that the slip prevention means is accommodated in the box punching hole 50. At this time, in the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, the stud SJ with a head and the head Sh that can be retrofitted are removed, and the precast floor slab 5 is placed and then attached. .. This is because if there is a head sh or the like having a large diameter, it may not be possible to install it because it interferes with the exposed reinforcing bar in the box punching hole 50 due to a dimensional error, or it may take a long time to install it.

Further, although not shown, it is preferable that the exposed reinforcing bar 51 of the box punching hole 50 is joined by a screw type mechanical joint so as to be removable. After the precast floor slab 5 is placed on the main girders T girders G1 to G4, the exposed reinforcing bars are attached to the box punching holes 50 to eliminate the interference between the slip prevention means Z1 and the exposed reinforcing bars in this process. This is because the working time of the process can be shortened.

As shown in FIG. 14, in the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, only the tension counter material such as stirrup Sr is fixed by the above-mentioned mechanical fixing means 1 to 3. The main girders are the T girders G1 to 4 where the stud portion is not formed, where the slip prevention means Z1 is connected to the mechanical fixing means 1 and 3 as described above, and where the slip prevention means is added by the post-construction anchor. It can be appropriately mixed depending on the position of the stirrup Sr and the structural calculation. Therefore, it is possible to deal with the bar arrangement status and dimensional error of the existing T girders G1 to 4.

Then, in this step, a filler M such as non-shrink mortar is filled between the precast floor slab 5 and the T girders G1 to G4 and the box punching hole 50 and cured, and the precast floor slab 5 and the main girders G1 to G4 are cured. To integrate with. By the completion of this step, the work of updating the concrete bridge to the precast slab according to the method of replacing the concrete bridge with the precast slab according to the present embodiment is completed.

According to the method for replacing the concrete bridge with the precast floor slab according to the embodiment of the present invention described above, the stirrup Sr of the T girders G1 to G4, which are the main girders of the bridge B1, is mechanically fixed to the means 1 to 3 and the like. The old and damaged RC floor slab F1 can be replaced with a new high-quality precast floor slab 5. Therefore, the floor slab of the existing concrete bridge B1 can be renewed at low cost and in a short period of time, and appropriate maintenance can be achieved to extend the life of the bridge B1.

Further, according to the method of replacing the concrete bridge with the precast slab according to the present embodiment, the newly installed precast slab 5 and the existing main girders T girders G1 to G4 can be integrated, and the precast can be integrated. Since the synthetic cross section including the floor slab 5 can counter the external force, the thickness of the newly installed precast floor slab 5 can be reduced to extend the life and durability of the existing T girders G1 to G4.

Further, according to the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, the head of the slip-preventing means having a large diameter can be retrofitted, and the exposed reinforcing bar in the box punching hole 50 due to a dimensional error. It becomes easy to place the precast floor slab 5 on the T girders G1 to G4 by preventing the precast floor slab 5 from being unable to be installed due to interference with the 51 or requiring a large amount of time to be installed.

In addition to that, according to the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, it is possible to add anti-slip means to the T girders G1 to G4 with post-construction anchors, and the number of necessary anti-slip means. It becomes easy to secure.

Further, according to the method of replacing the concrete bridge with the precast floor slab according to the present embodiment, the slip-preventing means continuous with the tensile resistance material such as stirrup Sr is penetrated through the box punching hole 50 of the newly installed precast floor slab 5. It is possible to install the existing main girders (T girders G1 to G4) in the vicinity of the reinforcing reinforcing bars 51 to be installed, and the existing main girders (T girders G1 to G4) can be firmly integrated with the newly installed precast floor slab 5.

The method of replacing the concrete bridge with the precast floor slab according to the embodiment of the present invention has been described in detail above, but any of the above-mentioned or illustrated embodiments is one embodiment embodied in carrying out the present invention. It is just an indication of. Therefore, the technical scope of the present invention should not be construed in a limited manner by these.

In particular, the T-girder bridge has been described as an example of a bridge to which the present invention is applied, but the bridge is not limited to the T-girder bridge. For example, as shown in FIG. 15, the present invention can also be applied to updating a concrete slab of a box girder bridge to a precast slab. Further, as shown in FIG. 16, the present invention can also be applied to updating a concrete slab of a slab bridge having a hollow slab (hollow slab) to a precast slab. In short, the present invention can be applied when replacing the RC slab of a concrete bridge with a precast slab.

1,2,3: Mechanical fixing means P1: Cylindrical steel P2: Cylindrical steel K1: Crust P3: Long nut M: Filler P: Non-landing adjustment material 5: Precast floor slab 50: Box punching hole 51: Exposed reinforcing bar 6 : Post-construction anchors Z1, Z2, Z3: Anti-slip means P4, P5: Cylindrical steel SJ: Stud with head SJ': Stud bolt Sb: Shaft Sh: Head B1: Bridge G1 to G4: T girder (main girder)
S1: Anti-slip rebar S2: Oblique rebar Sr: Stirrup (tensile resistance material)
F1: RC floor slab F1a: Main girder upper part W1: Wall railing W2: Ground covering part P1: Pavement W1, W2: Ground covering part X: Bridge axis direction Y: Bridge axis perpendicular direction Z: Vertical direction

Claims (7)

Replacing the RC slab of a concrete bridge with a precast slab This is a method of replacing a concrete bridge with a precast slab.
The upper part of the main girder to be joined to the RC slab of the concrete bridge was scraped off to expose the upper part of the tensile resistance material made of reinforcing bars , and the exposed tensile resistance material was cut in the middle to cut the mechanical fixing means . A precast floor slab having a box punching hole is mainly used as a precast floor slab which is fixed to the tensile resistance material and fixed so that the tensile resistance material does not shift in the material axial direction, and then a slip prevention means is connected to the mechanical fixing means. Concrete characterized in that it is placed on a girder, the slip prevention means is housed in the box punching hole, a filler is filled and hardened, and the precast slab and the main girder are integrated. How to replace the bridge with a precast floor slab. After the precast floor slab is placed on the main girder, the head of the slip prevention means connected to the mechanical fixing means is configured to be retrofitted to the shaft portion.
The method for replacing a concrete bridge with a precast slab according to claim 1, wherein the head of the slip-preventing means is attached to a shaft portion after the precast slab is placed on the main girder. The slip prevention means connected to the mechanical fixing means is configured to be retrofitted to the mechanical fixing means.
The method for replacing a concrete bridge with a precast slab according to claim 1, wherein the precast slab is placed on the main girder and then the slip prevention means is connected to the mechanical fixing means. As the slip prevention means, one connected to the mechanical fixing means and one connected to the main girder with a post-construction anchor are used in combination.
Any of claims 1 to 3, wherein a post-construction anchor is installed on the upper surface of the main girder to fix the slip prevention means to the main girder before the precast floor slab is placed on the main girder. How to replace the concrete bridge described in Crab with a precast floor slab. The method for replacing a concrete bridge with a precast floor slab according to any one of claims 1 to 4, wherein the reinforcing bars of the precast floor slab are exposed in the box punching hole. The exposed reinforcing bars are joined by a screw type mechanical joint so as to be removable.
The method for replacing a concrete bridge with a precast slab according to claim 5, wherein the precast slab is placed on the main girder and then an exposed reinforcing bar is attached to the box punching hole. The method for replacing a concrete bridge with a precast slab according to claim 1, wherein the slip-preventing means is a headed stud.

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