JP2019132070A - Precast floor slab for replacing pc composite girder and replacing method for pc composite girder precast floor slab - Google Patents

Abstract

To provide a precast floor slab for replacing a PC composite girder capable of reducing the construction period.SOLUTION: A replacement precast floor slab 20 has a joining space 22 in the lower part of a haunch part 21, and a part of buried steel plate 23 is exposed from the joining space 22. In the replacement precast floor slab 20 in the state of being rested on the main girder 3, a displacement preventing reinforcement 12 and a stirrup 13 of the main girder 3 are arranged.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a PC composite girder replacement precast floor slab that replaces an existing precast floor slab and a PC composite girder precast floor slab replacement method.

  Conventionally, the composite girder bridge structure of a bridge is either a steel girder joined with a concrete slab (hereinafter referred to as “steel composite girder bridge”) or a prestressed concrete girder (hereinafter referred to as “PC girder”). There is one in which concrete is cast and a floor slab and a PC girder are joined (hereinafter referred to as “PC composite girder bridge”). The former has many construction examples using precast slabs. In addition, precast slabs are also used as appropriate for repair work accompanying deterioration of the slabs. On the other hand, the latter floor slab is so-called cast-in-place concrete, and the floor slab is placed through a PC girder rebar. No construction examples using precast floor slabs have been reported. There are few examples of repair work accompanying the deterioration of floor slabs. There are no reports of repair cases using precast floor slabs.

  In the case of repairing precast slabs in steel composite girder bridges, the stud gibber is removed from the steel girder together with the concrete slab, and a new stud gibber becomes a steel girder again depending on the position of the hole in the replacement precast slab. Welded. A new precast floor slab is joined through the stud gibber. Following this construction method, if the rebar that joins the PC girder and the floor slab is cut in the repair work of the floor slab in the PC composite girder bridge, the rebar cannot be newly embedded in the PC girder. The girders and floor slabs cannot be joined. Therefore, this method cannot be used for repair work of floor slabs in PC composite girder bridges. For example, repair of floor slabs in PC composite girder bridges as in the repair method described in Patent Document 1 below. In the construction, the degraded floor slab is partially removed and the floor slab is reconstructed with cast-in-place concrete.

JP 2014-84590 A

  As mentioned above, in the composite girder bridge structure, the PC girder joins the floor slab and the PC girder, and the structure is different from the steel girder. A floor slab cannot be used. When cast-in-place concrete is placed on the floor slab, the repair work may take a long time due to the process of assembling the mold, curing, and drying.

  The present invention has been proposed in view of the above circumstances. In other words, precast floor slabs can be used in the repair work of floor slabs in PC girders, and this makes it possible to shorten the construction period, and to replace precast floor slabs for PC composite girders and precast floor slabs for PC composite girders. The purpose is to provide a replacement method.

  In order to achieve the above object, the precast floor slab for PC composite girder according to the present invention is replaced with a precast floor for PC composite girder which is joined in place of the existing floor slab joined to the existing concrete girder. The plate is characterized by having a joint space in which a reinforcing bar partially embedded in the upper end of the concrete girder is arranged.

  The replacement precast floor slab for PC composite girders according to the present invention is characterized in that a steel plate is provided in the joint space.

  The precast floor slab for replacement for PC composite girders according to the present invention is characterized in that the steel plate has a height adjusting means for adjusting the height relative to the concrete girders.

  In the precast floor slab for replacement of a PC composite girder according to the present invention, the plate surface of the steel plate is arranged in the bridge axis direction, and a protrusion is formed on the plate surface. A prestress is applied in a state where the lateral fastening cable is eccentric to the upper side.

  The replacement precast floor slab for PC composite girders according to the present invention is characterized in that the floor slab lateral fastening cable is eccentric while avoiding the joint space.

  The precast floor slab for PC composite girder according to the present invention has a fixing portion for applying prestress in the direction of the bridge axis, and is applied in the vicinity of the intermediate fulcrum to apply prestress in the direction of the bridge axis. A hole is formed.

  The PC composite girder replacement precast floor slab according to the present invention has a fixing portion for applying prestress in the direction of the bridge axis, and is constructed near the intermediate fulcrum portion.

  The method for replacing a precast floor slab for PC composite girders according to the present invention is a procedure for removing an existing floor slab joined to an existing concrete girder, leaving a reinforcing bar partially embedded in the upper end of the concrete girder, and And a procedure for laying a precast slab for PC composite girder replacement on the upper end of the concrete girder and a procedure for filling the joining space with a filler.

  The precast floor slab for PC composite girder according to the present invention has a joint space in which a reinforcing bar partially embedded in the upper end of a concrete girder is arranged. In other words, since the reinforcing bars left on the existing floor slab are removed are arranged in the joining space, the replacement precast floor slab for PC composite girders is joined to the concrete girders via the reinforcing bars. Therefore, a precast floor slab can be used in repair work of a floor slab joined to a concrete girder. As a result, the construction period and the traffic regulation period associated with the repair work can be shortened.

  The replacement precast floor slab for PC composite girders according to the present invention is provided with a steel plate in the joint space. That is, the replacement precast floor slab for PC composite girders is joined to the concrete girders via the steel plate. Therefore, the precast slab can be firmly joined in the repair work of the slab joined to the concrete girder.

  In the precast slab for replacement of a PC composite girder according to the present invention, the steel plate has a height adjusting means for adjusting the height relative to the concrete girder. Therefore, for example, the height of the replacement precast floor slab for PC composite girders can be adjusted according to the secular change of the existing structure, the dimensional error at the time of construction, or the like.

  The replacement precast floor slab for PC composite girders according to the present invention is such that the plate surface of the steel plate is arranged in the direction of the bridge axis, and a projection is formed on the plate surface. Prestress is applied with the cable being eccentric upward. That is, for example, when the precast floor slab for PC composite girder replacement is pre-stressed prestressed concrete, the floor slab lateral fastening cable is eccentric to the upper side, so that the compression force by the floor slab lateral fastening cable is reduced to PC It acts strongly on the upper surface of the precast slab for replacement of composite girders. In general, a bending stress is generated in the floor slab by passing a vehicle or the like, and in particular, a tensile stress is generated on the upper surface side of the floor slab. Therefore, by applying the compressive force of the floor slab side-clamping cable to the part where the tensile stress is generated, the precast floor slab for PC composite girder replacement can be effectively reinforced. The durability of the precast slab can be improved.

  In the precast floor slab for replacement for PC composite girders according to the present invention, the floor slab lateral fastening cable is eccentric so as to avoid the joint space. With this configuration, it is possible to prevent interference between the reinforcing bars arranged in the joining space and the floor slab horizontal fastening cable.

  The replacement precast slab for PC composite girders according to the present invention has holes for applying prestress in the bridge axis direction. With this configuration, it is possible to counter the tensile stress resulting from the age difference between the concrete girder and the replacement precast slab for PC composite girder. The durability and load bearing capacity of the replacement precast slab for PC composite girder Can be maintained. Generally, concrete shrinks due to drying or the like, but the new floor slab has a large degree of shrinkage, and the existing old main girder has little shrinkage or has already been finished. For this reason, in a PC girder whose rigidity of the main girder is higher than that of the floor slab, the contraction of the floor slab is restrained by the main girder, and tensile stress is generated in the floor slab. Therefore, by applying pre-stress in the bridge axis direction of the PC composite girder replacement precast floor slab, it becomes possible to join the PC composite girder replacement precast floor slabs together. The durability of the precast slab is also improved.

  In the repair work of the steel composite girder bridge, since the cross section of the steel girder is small, there is almost no influence by the shrinkage of the precast floor slab, and the prestress is not applied in the direction of the bridge axis. Therefore, in the steel composite girder bridge, the precast floor slabs are joined to each other by a reinforcing bar joint or the like.

  In general, many PC composite girder bridges have a structure in which PC bridges spanned between a plurality of piers (spans) are connected on a pier (intermediate fulcrum). In this intermediate fulcrum, PC steel is additionally arranged on the PC girders and floor slabs to connect the PC bridge.

  The replacement precast floor slab for PC composite girders according to the present invention has a fixing portion for applying prestress in the direction of the bridge axis, and is installed near the intermediate fulcrum portion. With this configuration, it is possible to counter the tensile stress in the vicinity of the intermediate fulcrum caused by the structural characteristics of the PC composite girder. In general, in a continuous girder bridge structure or a connected girder structure in which bridge girders constructed between multiple piers are joined, the neutral axis is near the intermediate fulcrum due to live or dead loads of vehicles loaded on the bridge. Tensile stress is generated in the upward direction. Therefore, the precast floor slab for PC composite girder replacement is effectively reinforced by adding prestress in the bridge axis direction near the intermediate fulcrum and joining the PC precast girder replacement precast slabs together. can do. In addition, it is only necessary to provide a fixing unit for the PC composite girder replacement precast floor slab installed in the vicinity of the intermediate fulcrum part. Therefore, PC synthesis is performed in the vicinity of the intermediate fulcrum part and other standard parts. By dividing the specifications of the precast slab for replacement for girders, the economy can be improved.

  The method for replacing a precast floor slab for PC composite girders according to the present invention is a procedure for removing an existing floor slab joined to an existing concrete girder, leaving a rebar partially embedded in the upper end of the concrete girder, It includes a procedure for laying the above-mentioned precast slab for PC composite girder replacement on the upper end of the concrete girder and a procedure for filling the joint space with a filler. In other words, the reinforcing bars left behind after the existing floor slabs are removed are placed in the joint space, and the joint space is filled with a filler, so that the precast floor slab for PC composite girders is replaced with concrete girders via the reinforcing bars. To join. Therefore, the precast floor slab for PC composite girder can be used in the repair work of the floor slab joined to the concrete girder, and the construction period can be shortened.

FIG. 1 is a cross-sectional view of a bridge girder provided with a replacement precast floor slab for a PC composite girder according to an embodiment of the present invention, and is a partial cross-sectional view seen from the bridge axis direction. FIG. 2 is an enlarged view of a portion A of FIG. 1, which is an enlarged cross-sectional view of a main part of the bridge girder provided with the replacement precast floor slab for PC composite girder according to the embodiment of the present invention. . FIG. 3 is a partially transparent perspective view of a bridge girder provided with a precast floor slab for PC composite girder according to an embodiment of the present invention. FIG. 4 is an enlarged view of a portion A of FIG. 1, in which the cross section of the bridge girder in which the precast floor slab for PC composite girder according to the embodiment of the present invention is installed together with the height adjusting means is enlarged. FIG. FIG. 5 is a first procedure explanatory diagram showing the procedure of the method for replacing the precast floor slab for PC composite girders according to the embodiment of the present invention. FIG. 6 is a second procedure explanatory diagram showing the procedure of the method for replacing the precast floor slab for PC composite girders according to the embodiment of the present invention. FIG. 7 is a third procedure explanatory view showing the procedure of the method for replacing the precast floor slab for PC composite girders according to the embodiment of the present invention. FIG. 8 is a third procedure explanatory diagram showing the procedure of the method for replacing the precast floor slab for PC composite girders according to the embodiment of the present invention. FIG. 9 is a fourth procedure explanatory diagram showing the procedure of the method for replacing the precast floor slab for PC composite girders according to the embodiment of the present invention. (A) is BB side surface cross section in (b), Comprising: The partial side surface sectional view seen from the bridge-axis orthogonal direction, (b) is AA cross section in (a), Comprising: It is a plane sectional view. . FIG. 10 is a fifth procedure explanatory diagram showing the procedure of the method for replacing the precast floor slab for PC composite girders according to the embodiment of the present invention. FIG. 11 is a fifth procedure explanatory diagram showing the procedure of the method for replacing the precast floor slab for PC composite girders according to the embodiment of the present invention. FIG. 12 is a seventh explanatory diagram showing the procedure of the method for replacing the precast floor slab for PC composite girders according to the embodiment of the present invention. FIG. 13 is an eighth procedure of the replacement method of the precast floor slab for PC composite girders according to the embodiment of the present invention, and the bridge shaft in the bridge girder provided with the precast floor slab for PC composite girder It is the schematic side view seen from the right angle direction. FIG. 14 is an eighth procedure of the replacement method of the precast floor slab for PC composite girders according to the embodiment of the present invention, and the bridge shaft in the bridge girder provided with the precast floor slab for PC composite girder It is the fragmentary sectional view seen from the direction.

  Hereinafter, a method for replacing a precast floor slab for PC composite girders (hereinafter referred to as “precast floor slab for replacement”) and a precast floor slab for PC composite girders according to an embodiment of the present invention will be described with reference to the drawings. This will be explained based on. 1 to 4 show a bridge girder 1 provided with a precast floor slab 20 for replacement. 1 shows a partial cross section viewed from the bridge axis direction, FIGS. 2 and 4 show an enlarged partial cross section of a precast floor slab 20 for replacement, and FIG. 3 shows a precast for replacement. The floor slab 20 is shown in perspective.

  As shown in FIG. 1, the replacement precast floor slab 20 is joined to the concrete girder 2 instead of the existing floor slab joined to the existing concrete girder 2, and this replacement precast Using the floor slab 20, a method for replacing the precast floor slab for PC composite girders is realized. The concrete girder 2 is composed of, for example, an I-type PC girder, which is the main girder 3, a horizontal girder 5, and the like. The replacement precast floor slab 20 is elongated in the direction perpendicular to the bridge axis, and a plurality of hunch portions 21 are formed corresponding to the plurality of main girders 3. The specifications of the replacement precast slab 20 differ between the intermediate fulcrum part (see the right half in FIG. 1) and the other standard part (see the left half in FIG. 1). The replacement precast floor slab 20 at the intermediate fulcrum is a replacement precast floor slab 32 with a PC fixing part on which a PC fixing part 33 for fixing PC steel material is formed. In the plate 20, the PC fixing portion 33 is not formed. The PC fixing portion 33 is formed between the hunch portions 21. Each of the replacement precast slabs 20 is provided with a PC steel material arrangement hole 30 through which the PC steel material is passed in order to apply prestress in the bridge axis direction. The PC steel material arrangement hole 30 is formed by a sheath (not shown). The replacement precast floor slab 32 with the PC fixing unit has the same configuration as the replacement precast floor slab 20 except for the PC fixing unit 33. The replacement precast floor slab 20 may have a prestressed concrete structure or a reinforced concrete structure.

  As shown in FIGS. 2 and 3, the replacement precast slab 20 has a width in the direction of the bridge axis of about 1 to 2 meters, and the lower portion of the haunch portion 21 is cut away to have a joint space 22. doing. The joint space 22 is a concave depression in which the lower surface of the haunch portion 21 is opened. A steel plate 23 is embedded in the replacement precast floor slab 20, and a part of the steel plate 23 is exposed in the joining space 22. The steel plate 23 has a flat plate shape and a total length longer than the width of the haunch portion 21. A plurality of steel plates 23 are arranged in the bridge axis direction with the plate surface directed in the bridge axis direction, and a plurality of plate holes 25 are formed in the plate surface. The number of the plate holes 25 is arbitrary. The steel plate 23 is firmly fixed to the precast floor slab 20 for replacement by passing the PC steel through the plate hole 25 and filling with concrete.

  In the steel plate 23, two projecting portions 26 projecting downward toward the main girder 3 are formed at the lower portion of the plate exposed portion 24 that is a portion exposed in the joining space 22. The number of the protrusions 26 is arbitrary. Of the steel plate 23, the plate surface of the plate embedding portion 27, which is a portion embedded in the replacement precast floor slab 20, is formed with a plurality of projecting portions 28 projecting in the bridge axis direction. The protrusion 28 may be, for example, a rod that penetrates the steel plate 23. When the replacement precast floor slab 20 has a prestressed concrete structure, the PC 28, which is a floor slab side-clamping cable, is eccentric to the upper side with respect to the direction perpendicular to the bridge axis and the joining space 22 by the projection 28. Pre-stress is applied while avoiding On the other hand, when the precast slab 20 for replacement has a reinforced concrete structure, the PC steel material 31 is not disposed.

  As shown in FIG. 4, the height adjusting means 29 may be attached to the protruding portion 26 of the steel plate 23. The height adjusting means 29 adjusts the height with respect to the main girder 3. For example, a member in which a screw groove is engraved on a member, a jack structure, a plate-like spacer, etc. It is.

  As shown in FIGS. 2 to 4, in a state where the replacement precast floor slab 20 is disposed on the main girder 3, the protruding portion 26 is placed on the upper surface of the main girder 3. In the joint space 22, reinforcing bars such as a misalignment reinforcing bar 12 and a stirrup 13 which are embedded in the upper part of the main girder 3 and partially exposed from the upper end of the main girder 3 are arranged.

  As described above, the replacement precast floor slab 20 is configured. Next, a method for replacing the precast floor slab for PC composite girders will be described with reference to the drawings. 5 to 14 show a first procedure to an eighth procedure regarding the method of replacing the precast floor slab for PC composite girders. Here, as shown in FIG. 13, the replacement method of the precast floor slab for PC composite girders uses the replacement precast floor slab 20 in the standard part, and the replacement precast floor in the intermediate fulcrum part. Since the plate 20 and the precast floor slab 32 for replacement with the PC fixing unit are used, the procedure differs between the standard part and the intermediate fulcrum part. In the standard part, the first procedure is followed by the seventh procedure. At the intermediate fulcrum part, after going through the fifth procedure from the first procedure, go through the seventh procedure and the eighth procedure. In addition, the construction order of a standard part and an intermediate fulcrum part changes with conditions and construction conditions of a structure. Examining each structure as appropriate, and determining the construction order.

  First, the procedure of the method for replacing the precast floor slab for PC composite girders in the standard part will be described. In the repair work of the bridge girder 1, traffic regulations will be implemented as appropriate before going through each procedure.

  As shown in FIG. 5, in the first procedure, the existing floor slab 6 joined to the main girder 3 is cut with a concrete cutter (not shown). The cutting point X is a position where the flange 4 of the main beam 3 is left. At that time, in order to prevent the existing floor slab 6 from falling, the existing floor slab 6 is temporarily fixed with a steel material (not shown).

  As shown in FIG. 6, in the second procedure, the cut existing floor slab 6 is lifted and removed by, for example, a hydraulic crane (not shown).

  As shown in FIG. 7, in the third procedure, the rest of the existing floor slab 6 left immediately above the main beam 3 is removed. At that time, as shown in FIG. 8, the shift prevention reinforcing bars 12 and the stirrup 13 of the main girder 3 are left on the upper part of the main girder 3. For example, the existing floor slab 6 is removed by a concrete crushing apparatus (not shown) using ultra-high pressure water, and damage to the misalignment reinforcing bars 12 and the stirrup 13 is avoided.

  As shown in FIG. 9, in the fourth procedure, the existing floor slab 6 of the intermediate cross beam 7 is removed leaving the cross beam 5. At that time, the existing floor slab 6 is attached leaving the stirrup (not shown) embedded in the cross beam 5.

  As shown in FIGS. 10 and 11, in the fifth procedure, the replacement precast floor slab 20 is installed on the main girder 3. In the state where the replacement precast floor slab 20 is suspended from the suspension beam 9 by the wire 8, the suspension beam 9 is lifted by the suspension wire 10 by the crane. The precast floor slab 20 for replacement is installed in order in the bridge axis direction. In the standard part, a replacement precast floor slab 20 is installed, and before and after the intermediate fulcrum part, a replacement precast floor slab 32 with a PC fixing part is installed (see FIG. 12). The erection work is, for example, crane erection from a bridge surface, crane erection from a bridge side, erection using an erection machine, and the like.

  When the replacement precast floor slab 20 is installed, the misalignment reinforcing bars 12 and the stirrup 13 are disposed in the joining space 22, and the protruding portion 26 of the steel plate 23 is placed on the upper surface of the main girder 3. The position is adjusted as Further, the height of the replacement precast slab 20 is adjusted by the height adjusting means 29 according to the bridge surface.

  In the sixth procedure, prestress is applied in the bridge axis direction, and the replacement precast slabs 20 are joined together. More specifically, first, the replacement precast floor slabs 20 are brought into close contact with each other with an adhesive. When joints are provided in consideration of construction errors, mortar or the like is placed on the joints. Next, when the PC steel material is inserted into the PC steel material arrangement hole 30 and the mortar placed on the joint has a predetermined strength, the PC steel material is tensioned. As the mortar, one having a compressive strength comparable to that of the replacement precast slab 20 is used.

  As shown in FIG. 12, in the seventh procedure, the filler 11 is filled into the joining space 22. Mortar or the like is injected as a filler 11 into a placement hole (not shown) provided in the replacement precast floor slab 20 in advance, and mortar is placed in the joining space 22. The placing hole is formed at a position where it does not interfere with the steel plate 23 or the like. As the mortar, one having a compressive strength comparable to that of the replacement precast slab 20 is used. The mortar is cured and the replacement precast floor slab 20 is joined to the main beam 3. In addition, when the difference arises in the height of a pavement top edge by the precast floor slab 20 for replacement | exchange, it rubs suitably and eliminates a level | step difference.

  As described above, in the standard part, the procedure of the method for replacing the precast floor slab for PC composite girders is advanced. Next, the procedure of the method for replacing the precast floor slab for PC composite girders at the intermediate fulcrum will be described. The intermediate fulcrum part has the purpose of connecting the PC bridge in the bridge axis direction in addition to the replacement of the floor slab, so after going through the fifth procedure from the first procedure, the seventh procedure and the following eighth procedure. The first to fifth procedures are the same as the standard part.

  As shown in FIGS. 13 and 14, in the eighth procedure, prestress is applied in the bridge axis direction at the intermediate fulcrum portion. Here, the PC steel material is inserted into the PC fixing portion 33 of the replacement precast floor slab 32 with a PC fixing portion, and is tensioned.

  As described above, the replacement method of the precast floor slab for PC composite girders is implemented, and the repair work for bridge girder 1 is completed. Next, the effect of this embodiment will be described.

  As described above, the replacement precast floor slab 20 has a joining space 22 in which the lower portion of the haunch portion 21 is cut away. In the joint space 22, the displacement prevention reinforcing bar 12, the stirrup 13, etc. of the main girder 3 are arranged in a state where the replacement precast floor slab 20 is placed on the main girder 3 (see FIGS. 2 and 3). ). In other words, since the misalignment rebar 12 and the stirrup 13 left on the trace of the existing floor slab 6 being removed are arranged in the joining space 22, the replacement precast floor via the misalignment rebar 12 and the stirrup 13 is provided. The plate 20 is joined to the main beam 3. Therefore, a precast floor slab can be used in the repair work of the bridge girder 1. As a result, the construction period and the traffic regulation period associated with the repair work can be shortened.

  The replacement precast floor slab 20 has a steel plate 23 embedded therein, and the steel plate 23 has a plate exposed portion 24 exposed in the joining space 22 (see FIGS. 2 and 3). That is, the replacement precast floor slab 20 is joined to the main girder 3 via the steel plate 23. Therefore, in the repair work of the bridge girder 1, the replacement precast floor slab 20 can be firmly joined.

  The steel plate 23 of the replacement precast slab has height adjusting means 29 for adjusting the height relative to the main girder 3 (see FIG. 4). Therefore, for example, the height of the replacement precast floor slab 20 can be adjusted according to the bridge surface in accordance with the secular change of the existing structure, the dimensional error at the time of construction, and the like.

  When the replacement precast floor slab 20 has a prestressed concrete structure, the steel plate 23 is formed with a plurality of protrusions 28 protruding in the bridge axis direction on the plate surface of the plate embedding portion 27 ( (See FIG. 2). Prestress is applied in a state where the PC steel material 31 is decentered upward with respect to the direction perpendicular to the bridge axis and avoids the joint space 22. That is, for example, when the replacement precast floor slab 20 has a pre-tensioned prestressed concrete structure, the PC steel 31 is eccentric toward the upper side, so that the compression force of the PC steel 31 is changed. It acts strongly on the upper surface of 20. The replacement precast floor slab 20 can be effectively reinforced by applying a compressive force of the PC steel material 31 to the upper surface portion where tensile stress is generated by passage of a vehicle or the like. The durability of can be improved. Further, the interference between the anti-displacement reinforcing bar 12 or the stirrup 13 and the PC steel material 31 arranged in the joining space 22 can be prevented. From this, the applicability of the replacement precast floor slab 20 can be expanded, and improvement in quality and economy can be realized.

  The replacement precast floor slab 20 has PC steel material placement holes 30 through which the PC steel material is passed in order to apply prestress in the bridge axis direction (see FIGS. 2 and 3). With this configuration, it is possible to counter the tensile stress resulting from the age difference between the main girder 3 and the replacement precast floor slab 20, and to maintain the durability and load resistance of the replacement precast floor slab 20 it can.

  The precast floor slab replacement method for PC composite girders goes from the first procedure to the eighth procedure (see FIGS. 5 to 14). In other words, the displacement prevention reinforcing bars 12 and the stirrup 13 left on the trace of the existing floor slab 6 being removed are arranged in the joining space 22 and the joining space 22 is filled with the filler 11, so The replacement precast floor slab 20 is joined to the main beam 3 via the wrap 13. Therefore, a precast floor slab can be used in the repair work of the bridge girder 1, thereby shortening the construction period and the traffic regulation period accompanying the repair work.

  In the fifth procedure, a replacement precast floor slab 20 is installed in the standard part, and a PC fixing part-attached precast floor slab 32 can be additionally provided before and after the intermediate fulcrum part compared to the standard part. Is constructed (see FIGS. 13 and 14). In the seventh procedure, a PC steel material is inserted and tensioned in the PC fixing portion 33 of the replacement precast floor slab 32 with the PC fixing portion, and prestress is applied in the bridge axis direction at the intermediate fulcrum portion. With this configuration, the tensile stress in the vicinity of the intermediate fulcrum portion can be counteracted, and the replacement precast floor slab 20 can be effectively reinforced. Further, the replacement precast floor slab 32 with the PC fixing portion, which has a higher manufacturing cost than the replacement precast floor slab 20, is installed only in the vicinity of the intermediate fulcrum portion, so that the economy can be improved.

  In addition, when the precast floor slab 20 for replacement has a reinforced concrete structure, there is no compression due to prestress, and therefore it can have an arbitrary shape in the direction perpendicular to the bridge axis. For example, the present invention can be applied to cases where the floor slab span is short or the gradient in the direction perpendicular to the bridge axis changes.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment. The present invention can be modified in various ways without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Bridge girder 2 Existing concrete girder 3 Main girder 4 Flange 5 Horizontal girder 6 Existing floor slab 7 Intermediate cross girder 8 Wire 9 Lifting beam 10 Suspension wire 11 Filler 12 Displacement prevention reinforcing bar (rebar)
13 Stirrup (rebar)
20 Precast floor slab for replacement (Precast floor slab for PC composite girder)
DESCRIPTION OF SYMBOLS 21 Haunch part 22 Joining space 23 Steel plate 24 Plate exposure part 25 Plate hole 26 Projection part 27 Plate embedding part 28 Projection part 29 Height adjustment means 30 Hole for PC steel material arrangement (hole)
31 PC steel (floor side cable)
32 Replacement precast slab with PC fixing part (Replacement precast slab for PC composite girder)
33 PC fixing part X Cutting point

Claims (8)

It is a precast slab for replacement for PC composite girder that is joined in place of an existing slab joined to an existing concrete girder,
Having a joint space in which a rebar partially embedded in the upper end of the concrete girder is arranged,
Replacement precast floor slab for PC composite girders. A steel plate was provided in the joining space,
The replacement precast floor slab for PC composite girders according to claim 1. The steel plate has height adjusting means for adjusting the height relative to the concrete girder,
The replacement precast floor slab for PC composite girders according to claim 2. The plate surface of the steel plate is arranged in the direction of the bridge axis, and a protrusion is formed on the plate surface. Prestress is applied in a state where the floor slab side-clamping cable is eccentric to the upper side by the protrusion. The
The precast floor slab for replacement for PC composite girders according to claim 2 or claim 3, wherein The floor slab lateral fastening cable is eccentric avoiding the joining space,
The precast slab for replacement for PC composite girders according to claim 4. A hole was formed to apply prestress in the direction of the bridge axis.
The precast slab for replacement for PC composite girders according to any one of claims 1 to 5, wherein It has a fixing part for prestressing in the direction of the bridge axis, and is installed near the intermediate fulcrum part.
The replacement precast floor slab for PC composite girders according to any one of claims 1 to 6, wherein A procedure for removing an existing floor slab joined to an existing concrete girder, leaving a rebar partially embedded at the upper end of the concrete girder;
A procedure for installing the precast floor slab for PC composite girder described in any one of claims 1 to 7 on an upper end of the concrete girder;
Filling the joining space with a filler.
A method of replacing a precast floor slab for PC composite girders, characterized in that.

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