JP7185567B2 - Bridge pier repair method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for repairing bridge piers, and more particularly to a method for repairing reinforced concrete piers in existing bridges.

A bridge has a floor slab on which a traffic route is placed, a bridge girder that supports the floor slab, and a bridge pier that supports the bridge girder. The bridge pier has a pedestal and a cross beam projecting outward from the upper end of the pedestal, and the cross girder supports the bridge girder.

Bearings such as seismic isolation shoes are installed between the cross girders and the bridge girders to absorb the vibrations generated by the traffic route. In some cases, the floor slabs and the bridge girders that support them are integrally formed, and in some cases, support beams that support all the bridge girders are provided in a direction orthogonal to the bridge girders.

Since bridges are installed outdoors and are rarely maintained, they are prone to deterioration. In particular, the horizontal girders installed at the upper ends of the pedestals protrude laterally from the pedestal in a cantilever style, and are the part that constantly receives the load and vibration from the floor slab. Deterioration may progress only in

Since roads and railroads built on bridges are often major traffic routes, it is difficult to suspend the use of bridges for repair work. For this reason, it is required to repair the bridge piers, especially the cross girders, while maintaining the traffic lanes of the bridge in a usable state.

It is possible to support the existing floor slabs and bridge girders with temporary materials, dismantle the bridge piers, and construct new bridges. However, in existing bridges, since the installed floor slabs are extended, there is a height limit associated with the floor slabs, and lifting work using cranes is not possible. In particular, when installing the cross beams, it was necessary to construct new cross beams on site, but the extension of the floor slabs made work extremely difficult.

Here, as a technique for repairing bridge piers, for example, the technique described in Patent Document 1 (Japanese Unexamined Patent Publication No. 08-296210) is known.

This Patent Document 1 describes dismantling and new construction of a bridge pier in a state in which temporary pillars are erected in front of and behind the target bridge pier to temporarily support the bridge girders. Here, the newly installed pedestals are made of steel, and when installing steel cross girders on top of the pedestals, they are constructed parallel to the road so that the construction work will not be done on the road under the elevated bridge. At the final stage, it is rotated horizontally by 90° and joined to the pedestal.

JP-A-08-296210

As mentioned above, the cross beams protrude outward from the pedestals in the form of cantilever beams, and are constantly subjected to loads and vibrations from the floor slabs. is fast.

In addition, in the technique described in Patent Document 1 mentioned above, the entire bridge pier, which is composed of the pedestal and the horizontal girder, is newly installed. In other words, not only the cross girders, which are particularly deteriorated, but also the pedestals, which have not deteriorated as much as the cross girders, have been newly installed.

Certainly, it is conceivable to newly install only the cross beams based on the technology described in Patent Document 1, but in that case, the existing reinforced concrete pedestals and steel cross beams must be joined. must. Patent Document 1 describes that a steel pedestal and a steel cross beam are welded together. can't

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for repairing bridge piers, which can newly install cross girders while leaving the pillars of reinforced concrete bridge piers intact.

In order to solve the above problems, the method for repairing a bridge pier according to claim 1 of the present invention is a method for repairing a reinforced concrete bridge pier having a pier and a cross beam projecting outward from the upper end of the pier. remove the cross girders and the upper parts of the pedestals connected to the cross girders, remove concrete over a predetermined height from the upper ends of the remaining pedestals, which are the pedestals after removal, to expose the reinforcing bars; A steel cross girder unit comprising a girder and a tubular pedestal is brought in to replace the removed cross girder and the top of the pedestal so that the exposed rebar is surrounded by the pedestal. and installing it on the remaining pedestal, using the pedestal portion as a formwork, pouring concrete to integrate the remaining pedestal and the steel cross beam unit.

Claim 2 of the present invention provides a bridge pier repair method according to claim 1, wherein the inner wall of the pier is provided with a plurality of steel rods extending inwardly. , characterized in that

According to claim 3 of the present invention, there is provided a bridge pier repairing method according to claim 1 or 2, wherein concrete is placed after the steel cross-beam unit is installed on the remaining pier. connecting anchor bars to the exposed rebars prior to installation.

According to a fourth aspect of the present invention, there is provided a bridge pier repairing method according to the third aspect of the invention, characterized in that the exposed reinforcing bars and the anchoring bars are connected by mechanical joints.

According to claim 5, there is provided a bridge pier repairing method according to any one of claims 1 to 4, wherein the cross beam and the upper part of the pier connected to the cross beam are removed. Firstly, the supporting means for receiving the load of the bridge girders supported by said cross girders is installed, then the bearings between said bridge girders and said cross girders are removed, and said residual pedestals and said steel cross girder units are integrated. the bearings are installed between the bridge girders and the steel cross-beam units and the support means are removed.

According to the present invention, the cross beams and the tops of the pedestals are removed to expose the rebar from the top ends of the remaining pedestals, the steel cross girder units are installed on top of the remaining pedestals, and the pedestals are poured with concrete. Since the remaining piers and the steel cross girder units are integrated, it is possible to install new cross girders while leaving the piers of the reinforced concrete bridge piers.

FIG. 2 is an explanatory diagram showing the bridge in the embodiment of the present invention from a direction intersecting with a traffic road; FIG. 2 is an explanatory diagram showing the direction along the traffic route of the bridge in FIG. 1; FIG. 10 is an explanatory diagram showing the carry-out mount installed for removing the upper part of the cross beam and the pedestal in repairing the bridge pier from the direction intersecting the traffic route of the bridge. FIG. 10 is an explanatory diagram showing, from the direction along the traffic route of the bridge, the carry-out frame and the support frame installed for removing the upper part of the cross beam and the pedestal in repairing the bridge pier; 1 is an explanatory view showing from the front a step in a bridge pier repairing method according to an embodiment of the present invention; FIG. FIG. 6 is an explanatory diagram showing from the front a step following FIG. 5 in the bridge pier repair method according to the embodiment of the present invention; FIG. 7 is an explanatory diagram showing from the front a step following FIG. 6 in the bridge pier repairing method according to the embodiment of the present invention; FIG. 8 is an explanatory diagram showing from the front a step following FIG. 7 in the bridge pier repairing method according to the embodiment of the present invention; FIG. 9 is an explanatory diagram showing from the front a step following FIG. 8 in the bridge pier repairing method according to the embodiment of the present invention; FIG. 10 is an explanatory diagram showing from the front a step following FIG. 9 in the bridge pier repairing method according to the embodiment of the present invention; FIG. 11 is an explanatory diagram showing from the front a step following FIG. 10 in the bridge pier repairing method according to the embodiment of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front cross-sectional view of a steel cross girder unit used in a bridge pier repairing method according to an embodiment of the present invention; FIG. 13 is a cross-sectional view of the steel crossbeam unit of FIG. 12 viewed from above; FIG. 13 is a cross-sectional view taken along line II of FIG. 12; FIG. 4 is a front view showing a steel cross girder unit installed on a residual pedestal;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment as an example of the present invention will be described in detail below with reference to the drawings. In the drawings for describing the embodiments, in principle, the same components are denoted by the same reference numerals, and repeated description thereof will be omitted.

FIG. 1 is an explanatory diagram showing a direction intersecting a traffic road of a bridge according to one embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a direction along the traffic road of the bridge in FIG.

As shown in these drawings, the bridge B includes a floor slab 10 on which a traffic route T such as a road on which vehicles run and a railway on which a train travels is placed, a bridge girder 11 supporting the floor slab 10, and a bridge pier supporting the bridge girder 11. 12. The bridge pier 12 is composed of a pedestal 12a extending in the vertical direction and a cross beam 12b projecting outward (outward crossing the extending direction of the traffic road T) from the upper end of the pedestal 12a. supports the bridge girder 11.

As shown, the crossbeam 12b extends laterally in two directions in a cantilever manner from the pedestal 12a. In the present application, the projecting portion is referred to as projecting portion 12ba. The lower part of the pedestal 12a is buried in the ground G, and a footing 12f for stabilizing the pedestal 12a is fixed.

In addition, between the bridge girder 11 and the horizontal girder 12b, the expansion and contraction of the upper structure (floor slab 10, bridge girder 11, etc.) due to the influence of temperature change is absorbed, and the expansion and contraction generated by vehicles, trains, etc. running on traffic roads. Bearings 13 are installed to receive the load of the bridge girders 11 supported by the horizontal girders 12b for the purpose of absorbing vibrations caused by the bridge.

The bridge pier 12 before repair is entirely made of reinforced concrete, and reinforcing bars R such as main bars and hoop bars (tie bars) are arranged vertically and horizontally in the concrete (Figs. 5 to 11, Fig. 15).

Now, as described above, the horizontal beams 12b that constitute the bridge piers 12 protrude from the piers 12a in the form of cantilever beams, and because they constantly receive loads and vibrations from the floor slab 10, they deteriorate particularly. is easy to progress. A method for repairing the bridge pier 12 by newly installing the deteriorated cross beam 12b will be described below.

The outline of the repair of the bridge pier 12 is to remove the deteriorated cross beam 12b and the upper part of the pedestal 12a connected to the cross beam 12b, and install a separately assembled steel cross beam unit CB in the removed part. be. Details of the method for repairing the bridge pier 12 will be described below.

Fig. 3 is an explanatory view showing the carry-out pedestal installed to remove the upper part of the cross beam and pedestal in the repair of the pier from the direction of crossing the traffic road of the bridge, and Fig. 4 is the cross girder and the pier in the repair of the pier. FIG. 10 is an explanatory view showing the carrying-out frame and the support frame installed for removing the upper part of the bridge from the direction along the traffic route of the bridge;

As shown in these drawings, when removing the cross beam 12b of the bridge pier 12 and the upper part of the pedestal 12a, first, a temporary support frame (support means) SS that receives the load of the bridge girder 11 supported by the cross beam 12b is installed. is installed, and a temporary unloading stand SU for unloading the projecting portion 12ba of the horizontal beam 12b is installed.

The support frame SS is composed of a base part SSa and a plurality of jack units SSb installed on the base part SSa. is loaded. In addition, the unloading platform SU is installed around the pedestal 12a, and is installed on the base part SUa composed of the upper supporting beam SUaa and the jack unit SUab for lifting and lowering the supporting beam SUaa, and the base part SUa. The unloading table SUb and the projecting portion 12ba of the horizontal beam 12b are fixed with a wire W to prevent the cut projecting portion 12ba from falling. The carry-out table SUb is for supporting the projecting portion 12ba during cutting and for placing the projecting portion 12ba on when the cut projecting portion 12ba is carried out by a forklift or the like. 10 is left, it is a temporary member necessary because the projecting portion 12ba cannot be hung by a crane from above.

Here, the support frame SS is removed in the final stage of repairing the bridge pier 12, but the carry-out stand SU is dismantled after the projecting portion 12ba is carried out. Further, if the projecting portion 12ba can be cut and carried out by a heavy machine or the like without installing the carry-out stand SU, the carry-out stand SU is unnecessary.

After the support frame SS and the carry-out frame SU are installed as described above, the cross beam 12b and the upper part of the pedestal 12a connected to the cross beam 12b are removed and replaced with the alternative steel cross beam unit CB. When removing the horizontal girder 12b and the like, the bearing 13 such as the seismic isolation shoe installed between the horizontal girder 12b and the bridge girder 11 is removed.

Here, FIGS. 5 to 11 are explanatory diagrams sequentially showing each step from the front of the bridge pier repair method according to one embodiment of the present invention, and FIG. 12 is a bridge pier repair according to one embodiment of the present invention. 13 is a plan view of the steel cross girder unit used in the method, FIG. 14 is a top view of the steel cross girder unit of FIG. 12, and FIG. 14 is a cross section along line II of FIG. FIG. 15 is a front view showing the steel cross beam unit installed on the residual pedestal. In FIGS. 5 to 11 and 15, the reinforcing bars of the piers are not exposed, but are shown through the inside of the piers for convenience of explanation.

As shown in FIG. 5, in the bridge pier 12 before repair, reinforcing bars R (main bars, hoop bars, etc.) are arranged from the pedestal 12a to the cross beam 12b. Therefore, the reinforcing bar R extends vertically so as to straddle the pedestal 12a and the cross beam 12b.

For such a bridge pier 12, as shown in FIG. 6, one overhanging portion 12ba of the horizontal girder 12b is placed on a carrying-out platform SUb to be cut and removed, and further, as shown in FIG. The other projecting portion 12ba is also cut and removed in the same manner. Then, the pedestal 12a is cut at the cutting position L in the drawing. As a result, as shown in FIG. 8, the cross beam 12b and the upper part of the pedestal 12a connected to the cross beam 12b are removed. Although the cutting position L is not particularly limited, it is set 500 mm below the upper end of the pedestal 12a (that is, the boundary between the pedestal 12a and the crossbeam 12b) in this embodiment.

Subsequently, as shown in FIG. 9, concrete is removed over a predetermined height M from the upper end of the partially removed pedestal 12aa (in this application, this is referred to as a "residual pedestal"), and the reinforcing bar is Expose the upper end of R. The removal of concrete is performed, for example, by drilling a core to form a peripheral edge on which the steel cross beam unit CB is placed, and then manually picking it up by an operator or crushing it using a hydraulic crusher. The exposed length of the reinforcing bar R (that is, the removed concrete height M) is also not particularly limited, but in the present embodiment, it is longer than the length that enables the jointing operation of the anchoring bar Rf, which will be described later. 180 mm.

Here, in the present embodiment, the projecting portion 12ba of the cross beam 12b is removed, the pedestal 12a is cut at the cutting position L, and then the concrete is removed to expose the reinforcing bar R. After removing the projecting portion 12ba and removing the concrete to expose the reinforcing bar R, the reinforcing bar R may be cut at the cutting position L.

After the reinforcing bars R are exposed, the steel cross-beam unit CB is carried in as a substitute for the top of the removed cross-beam 12b and pedestal 12a, and as shown in FIG. to be installed.

When carrying in the steel cross-beam unit CB, after lifting the steel cross-beam unit CB to a predetermined height outside the bridge B, it is slid horizontally along the lower side of the bridge girder 11 to remove the residual pedestal. Move to 12aa. The distance from the upper end of the exposed reinforcing bar R of the remaining pedestal 12aa to the bridge girder 11 is almost the same as the height of the steel cross girder unit CB, but since there is a margin for the height of the removed bearing 13, the distance from the bridge girder 11 is Even if there is a height limit, it is possible to carry it in. In this way, the upper end position of the exposed reinforcing bar R of the residual pedestal 12aa is at a height that allows the steel cross-beam unit CB to be slid along the lower side of the bridge girder 11 and to secure an interval for carrying in.

Further, on the outside of the bridge B, a rail for moving the steel cross beam unit CB and a temporary support frame for supporting the rail are provided. The support within the bridge B may be this support frame, or a dedicated frame may be provided separately. Since the outer side of the bridge B has no height restriction by the bridge girder 11, it is sufficient to lift the steel cross-beam unit CB from the ground to the rail with heavy machinery.

Here, as shown in FIGS. 12 to 14, the steel cross-beam unit CB includes a cross-beam portion CB1 corresponding to the removed cross-beam 12b, and a remaining pedestal 12aa corresponding to the top of the removed pedestal 12a. It consists of a cylindrical pedestal part CB2 that becomes a joint part with.

The cross beam portion CB1 includes a plate-shaped main girder CB1a having an outer shape, a stiffening wall CB1b erected in the main girder CB1a along the lateral direction so as to support the upper and lower main girder CB1a, and a stiffening wall. It consists of a stiffening plate CB1c arranged vertically in the main girder CB1a so as to intersect with the CB1b, and a reinforcing rib CB1d arranged along the longitudinal direction vertically in the main girder CB1a. Further, both longitudinal ends of the horizontal beam portion CB1 are opened so that workers can enter and exit. Each stiffening wall CB1b and the bottom main girder CB1a are provided with access openings CB1e through which workers can work inside (connection of anchoring bars Rf, placing of concrete, etc., which will be described later). ing.

The pedestal portion CB2 has a cylindrical shape with an opening having substantially the same shape as the outer peripheral shape of the residual pedestal 12aa. Therefore, when the pedestal section CB2 is placed on the upper end of the concrete of the remaining pedestal 12aa to install the steel cross-beam unit CB, the exposed rebar R is surrounded by the pedestal section CB2. Further, steel stud bolts (rods) CB2a extending radially inward are provided on the inner wall of the pedestal portion CB2 over a plurality of stages in the vertical direction. In this embodiment, the pedestal portion CB2 is placed on the upper end of the concrete of the remaining pedestal 12aa. can be

Now, if the steel cross-beam unit CB is installed on the residual pedestal 12aa in this way, as shown in FIG. Connect Rf. Here, in the present embodiment, connection of the anchoring bar Rf is performed by a mechanical joint MJ. The mechanical joint MJ is a steel pipe in which a hole into which a reinforcing bar is inserted is formed in the axial direction, and the inner periphery of the hole is internally threaded. Then, when the reinforcing bar R is inserted from one end of the mechanical joint MJ and the anchoring bar Rf is inserted from the other end, the joints of the reinforcing bar R and the anchoring bar Rf are engaged with the mechanical joint MJ which is internally threaded to connect them. be. The bending angle of the hook may be 135° or 90°. Further, the fixing streak Rf may not necessarily have a hook, but it is desirable to have a hook because the fixing force increases.

The connection between the reinforcing bar R and the anchoring bar Rf is not limited to the mechanical joint MJ. A method in which the ends of the rebars are butted together and then heated and pressurized to integrate the reinforcing bars), or a weld joint (a method in which the ends of the rebars are butted and the rebars are integrated by welding) may be used. However, it is preferable to use the mechanical joint MJ, which is easy to work on site and has a short length required for the joint.

After connecting the anchoring bar Rf to the reinforcing bar R in this manner, concrete is placed in the pedestal portion CB2 from above (that is, from the access opening CB1e formed in the main girder CB1a on the bottom). As described above, the exposed reinforcing bars R of the residual pedestal 12aa are surrounded by the pedestal portion CB2 of the steel cross beam unit CB. The residual pedestal 12aa and the steel cross beam unit CB are integrated.

After the concrete placed on the pedestal portion CB2 has hardened, the bearing 13 is installed between the bridge girder 11 and the steel cross-beam unit CB, and the jack unit SSb of the support frame SS is unloaded to remove the bridge girder 11. It is fixed to the bearing 13 . Finally, the support frame SS is dismantled and removed to complete a series of repair work.

As described above, in the present embodiment, while the floor slab 10 and the bridge girder 11 are left, the upper parts of the horizontal girder 12b and the pedestal 12a are removed to expose the reinforcing bar R from the upper end of the residual pedestal 12aa. A steel cross-beam unit CB is installed on the pedestal 12aa, and concrete is poured into the pedestal part CB2 to integrate the remaining pedestal 12aa and the steel cross-beam unit CB. It becomes possible to newly install the cross beam 12b while leaving the pedestal 12a of the bridge pier 12.例文帳に追加

Although the invention made by the present inventor has been specifically described based on the embodiments, the embodiments disclosed in this specification are illustrative in all respects and are limited to the disclosed technology. is not. That is, the technical scope of the present invention should not be construed in a restrictive manner based on the description of the above embodiments, but should be construed according to the description of the scope of claims. All modifications are included as long as they do not deviate from the description technology and equivalent technology and the gist of the claims.

For example, the stud bolt CB2a of the pedestal part CB2 and the anchoring bar Rf connected to the reinforcing bar R of the residual pedestal 12aa are used to increase the joint strength between the residual pedestal 12aa and the steel cross beam unit CB by the cast concrete. used for However, depending on factors such as the size of the pier 12, the height of the pedestal portion CB2, and the length of the exposed reinforcing bar R in the residual pedestal 12aa, either one or both of the stud bolt CB2a and anchoring bar Rf may not be present. It is conceivable that the required bonding strength can also be obtained. In such a case, the stud bolt CB2a and the fixing bar Rf can be omitted. Also, the openings provided for workers to enter and exit the horizontal beam portion CB1 need not be located at both ends in the longitudinal direction, and may be located at either end or may be located at the front side.

INDUSTRIAL APPLICABILITY The present invention can be widely applied to the repair of reinforced concrete bridge piers, and the structure type of the bridge is not limited.

10 Floor slab 11 Bridge girder 12 Bridge pier 12a Pedestal 12aa Remaining pedestal 12b Cross girder 12ba Overhang 12f Footing 13 Bearing B Bridge CB Steel cross girder unit CB1 Cross girder CB1a Main girder CB1b Stiffening wall CB1c Stiffening plate CB1d Rib CB1e Entrance CB2 Pedestal CB2a Stud bolt (rod)
L Cutting position MJ Mechanical joint R Reinforcement bar Rf Fixing bar SS Support stand (support means)
SSa Base part SSb Jack unit SU Unloading platform SUa Base part SUaa Support beam SUab Jack unit SUb Unloading platform

Claims (5)

A method for repairing a reinforced concrete bridge pier having a pedestal and a cross beam projecting outward from the upper end of the pedestal, comprising:
removing the crossbeam and the upper part of the pedestal that is continuous with the crossbeam;
Removing concrete over a predetermined height from the upper end of the residual pedestal, which is the pedestal after removal, to expose the reinforcing bar;
A steel crossbeam unit comprising crossbeams and tubular pedestals to replace the removed crossbeams and tops of the pedestals is brought in and the exposed reinforcing bars are surrounded by the pedestals. installed on the residual pedestal in such a way that
Concrete is cast using the pedestal portion as a formwork to integrate the residual pedestal and the steel cross beam unit.
A bridge pier repair method characterized by: The inner wall of the pedestal is provided with a plurality of steel rods extending inward,
The bridge pier repairing method according to claim 1, characterized in that: connecting anchor bars to the exposed rebar after installing the steel crossbeam unit on the residual pedestal and before pouring the concrete;
3. The bridge pier repairing method according to claim 1 or 2, characterized in that: connecting the exposed rebar and the anchoring bar with a mechanical joint;
The bridge pier repairing method according to claim 3, characterized in that: Prior to the removal of the cross girder and the upper part of the pedestal connected to the cross girder, a support means for receiving the load of the bridge girder supported by the cross girder is installed, and then the bridge girder and the cross girder are separated from each other. Remove the bearing and
installing the bearing between the bridge girder and the steel cross girder unit and removing the support means after the residual pedestal and the steel cross girder unit are integrated;
The bridge pier repair method according to any one of claims 1 to 4, characterized in that:

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