JP2024151537A - Bridges and their construction methods - Google Patents

Abstract

To provide a bridge and its construction method capable of reducing a burden on a lower structure such as a bridge pier and shortening a construction period.SOLUTION: A bridge 1 comprises a substructure transverse beam 4 supported on the upper parts of each lower structure 3a, 3a in the direction perpendicular to the bridge-axis, vertical girder parts LB, LB composed of one or a plurality of hollow rectangular parallelepiped precast vertical girder members 6, 6 directed in the bridge-axis direction supported on the substructure transverse beam 4 through bearing members 5, and precast slab 7 installed between vertical girder parts LB, LB adjacent to each other at an interval in the direction perpendicular to the bridge axis, and prestress is introduced by a post-tensioning system over the whole width in the direction perpendicular to the bridge axis of a superstructure 8 by PC steel materials 9, 9... inserted in the direction perpendicular to the bridge axis of the superstructure 8 comprising the precast vertical girder members 6, 6 and the precast slab 7.SELECTED DRAWING: Figure 3

Description

The present invention relates to a bridge and a method for constructing a new bridge, including an elevated road, or to replace the existing bridge.

In recent years, concrete bridges have been facing problems with deterioration due to age, as well as the worsening environment caused by larger vehicles and the effects of antifreeze spraying, and large-scale renovation work is underway to replace bridges.

In particular, RC hollow deck bridges have gaps inside the deck that are supported by substructures such as piers in order to reduce dead loads, making them susceptible to salt and frost damage from antifreeze agents, and because the gaps make it difficult to ensure sufficient cover, the upper surface is prone to deformation due to heavy traffic and seepage water. If deformation occurs in the upper surface, the entire deck must be replaced.

In addition, RC hollow deck bridges are widely used as the standard structure for viaducts, and it is expected that many renewal works will be required in the future.

Conventionally, the most common method for replacing bridges such as RC hollow deck bridges has been to remove the existing superstructure using shoring or girders, and then build a new hollow deck or steel girder bridge in the removed area.

Another construction method that has been developed is to remove the existing superstructure, then install precast cross beams perpendicular to the bridge axis on the substructure such as piers or abutments, and then lay multiple hollow rectangular precast vertical beam members on the precast cross beams in a direction perpendicular to the bridge axis to construct a hollow deck (see, for example, Patent Document 1).

In addition, when replacing this type of bridge, traffic restrictions are imposed due to the removal of the existing superstructure, such as the deck, so there is a demand for a construction method that allows replacement in a short period of time to minimize the social losses caused by traffic restrictions.

JP 2009-256873 A

However, in the conventional technology shown in Patent Document 1 mentioned above, multiple precast vertical beam members are laid in a line perpendicular to the bridge axis on precast cross beams installed on substructures such as piers or abutments, which increases the weight of the entire superstructure and raises concerns about the insufficient strength of the substructures that support it.

Furthermore, with conventional technology, precast cross beams could only be installed after the existing superstructure had been removed, meaning that traffic restrictions had to be implemented throughout the entire period from the removal of the existing superstructure through the installation of the precast cross beams to the formation of the new deck, resulting in significant social losses due to the traffic restrictions.

In view of these conventional problems, the present invention was made with the aim of providing a bridge and a method for constructing the same that can reduce the burden on substructures such as bridge piers and shorten the construction period.

The feature of the invention described in claim 1 for solving the above-mentioned conventional problems is that in a bridge in which a superstructure is erected between substructures erected at intervals in the bridge axis direction, the bridge comprises a substructure cross beam supported on the upper part of each substructure in a direction perpendicular to the bridge axis, a vertical beam section made of one or more hollow rectangular parallelepiped precast vertical beam members facing in the bridge axis direction and supported on the substructure cross beams via bearing members, and a precast plate erected between adjacent vertical beam sections at intervals in the direction perpendicular to the bridge axis, and The cross beam is formed by filling the area surrounded by the adjacent vertical beams and the precast plate with concrete at a distance above the cross beam, and prestress is introduced by the post-tensioning method across the entire width of the structure consisting of the vertical beams, the precast plate, and the cross beam, in the direction perpendicular to the bridge axis, by the PC steel inserted across the entire width of the deck section consisting of the precast vertical beam members and the precast plate, and the PC steel inserted across the entire width of the cross beam in the direction perpendicular to the bridge axis.

The invention described in claim 2 is characterized in that, in addition to the configuration of claim 1, the substructure cross beam is supported at a position a predetermined height lower than the upper end of the substructure.

The invention described in claim 3 is characterized in that, in addition to the configuration of claim 1 or 2, prestress is introduced to the precast slab by the pretensioning method using PC steel members oriented in the bridge axis direction.

The invention described in claim 4 is characterized in that in a method of constructing a bridge in which a superstructure is erected between substructures erected at intervals in the bridge axis direction, a substructure cross beam facing perpendicular to the bridge axis is supported on the upper part of each substructure, and one or more hollow rectangular parallelepiped precast vertical beam members facing the bridge axis direction are supported on the substructure cross beams via bearing members to form vertical beam sections, after which precast panels are erected between adjacent vertical beam sections at intervals in the bridge axis direction, and adjacent vertical beam members are supported at intervals on the substructure cross beams. Concrete is poured into the area surrounded by the interlocking vertical beams and the precast slab to form the cross beams, and PC steel is inserted through the entire width of the deck section consisting of the precast vertical beams and the precast slab in the direction perpendicular to the bridge axis, and PC steel is inserted through the entire width of the cross beam in the direction perpendicular to the bridge axis, and the PC steel introduces prestress by post-tensioning across the entire width of the structure consisting of the vertical beams, the precast slab, and the cross beam in the direction perpendicular to the bridge axis.

The invention described in claim 5 is characterized in that, in a bridge construction method in which an existing superstructure erected between substructures erected at intervals in the bridge axis direction is replaced with a new superstructure, a substructure cross beam facing perpendicular to the bridge axis is constructed in advance at a position a predetermined distance lower than the upper end of the substructure supporting the existing superstructure, and after removing the existing superstructure, one or more hollow rectangular parallelepiped precast vertical beam members facing in the bridge axis direction are supported via bearing members on both sides of the upper end of the substructure of the substructure to form a vertical beam portion, and then the upper end of the substructure is sandwiched between the substructure and the horizontal beam, forming a vertical beam portion. A precast plate is erected between the adjacent vertical beams, concrete is poured into the area surrounded by the adjacent vertical beams and the precast plate at a distance on the substructure cross beam to form a cross beam, PC steel is inserted through the entire width of the deck section consisting of the precast vertical beam member and the precast plate in the direction perpendicular to the bridge axis, and PC steel is inserted through the entire width of the cross beam in the direction perpendicular to the bridge axis, and prestress is introduced by the post-tensioning method using the PC steel across the entire width of the structure consisting of the vertical beams, the precast plate, and the cross beam in the direction perpendicular to the bridge axis.

Furthermore, the invention described in claim 6 is characterized in that, in addition to the configuration of claim 4 or 5, both ends of the girder support plate material installed on the support member perpendicular to the bridge axis are supported by the substructure cross beam via temporary support members, and multiple precast vertical beam members are installed in a line perpendicular to the bridge axis on the girder support plate material, and prestress is introduced by the post-tensioning method using the PC steel material across the entire width perpendicular to the bridge axis of the structure consisting of the vertical beam section, the precast plate, and the cross beam section, and then the temporary support members are removed.

The invention described in claim 7 is characterized in that, in addition to the configuration of claim 4 or 5, prestress is introduced to the precast slab by the pretensioning method using PC steel members oriented in the bridge axis direction.

By being provided with the configuration described in claim 1, the bridge of the present invention can reduce the weight of the entire superstructure and the burden on the substructure such as piers and abutments.

In addition, in the present invention, by providing the configuration described in claim 2, the position where the precast vertical beam members are supported is lower than the upper end of the lower structure, and the girder height of the precast vertical beam members can be increased accordingly. In addition, renovation work can be started while the existing superstructure remains in service, shortening the construction period and reducing social losses due to traffic restrictions.

In addition, in the present invention, by providing the configuration described in claim 3, the strength of the precast deck installed between the precast stringer members can be increased, and a high-strength superstructure can be constructed.

The bridge construction method according to the present invention, by incorporating the configuration described in claim 4, can reduce the weight of the entire superstructure and reduce the burden on the substructure such as piers and abutments.

In addition, by providing the configuration described in claim 5 of the present invention, it is possible to begin repair work while keeping the existing superstructure in service, shortening the construction period and reducing social losses due to traffic restrictions.

Furthermore, in the present invention, by providing the configuration described in claim 6, it is possible to support multiple precast stringer members with one support member.

Furthermore, in the present invention, by providing the configuration described in claim 7, the strength of the precast deck installed between the precast stringer members can be increased, and a high-strength superstructure can be constructed.

FIG. 1 is a side view showing an example of a bridge according to the present invention. 2 is a cross-sectional view taken along line AA in FIG. 1. This is an enlarged cross-sectional view taken along line A-A, showing the structural portion supporting the above-mentioned superstructure. This is an enlarged cross-sectional view along line B-B showing the structural portion supporting the above-mentioned superstructure. 1A is a plan view showing the end of the precast vertical beam member of the same, FIG. 1B is a side view of the same end, and FIG. 1C is a cross-sectional view taken along line CC of the same. 1A is a plan view of the precast slab shown in FIG. 1A, FIG. 1B is a side view of the same, and FIG. FIG. 2 is a plan view showing the joint between the precast slabs. FIG. 1 is an enlarged cross-sectional view showing the steps of the bridge construction method according to the present invention, in which (a) shows the state after the existing superstructure has been installed, (b) shows the state after the substructure cross beam has been constructed, and (c) shows the state after the support member has been installed. (d) is a diagram showing the above-mentioned precast vertical beam members after installation, (e) is a diagram showing the same precast plate after it has been erected, and (f) is a diagram showing the state in which concrete has been poured into the area surrounded by both precast vertical beam members and the precast plate on the same substructure cross beam. 4(g) shows the state in which prestress has been introduced across the entire width of the superstructure, and FIG. 4(h) shows the completed bridge.

Next, an embodiment of a bridge and a method for constructing the bridge according to the present invention will be described based on the examples shown in Figures 1 to 10. In the figures, reference numeral 1 denotes a bridge and reference numeral 2 denotes the ground.

The bridge 1 comprises a substructure 3 such as a pier erected at intervals in the bridge axis direction, a substructure cross beam 4 oriented perpendicular to the bridge axis and supported on the upper part of the substructure 3, support members 5 arranged at intervals in the direction perpendicular to the bridge axis on the substructure cross beam 4, vertical beam sections LB, LB consisting of one or more precast vertical beam members 6, 6 installed via each support member 5, and a precast plate 7 erected between adjacent vertical beam sections LB, LB at intervals in the direction perpendicular to the bridge axis. The area surrounded by the slab 7 is filled with concrete 23 to form the cross beam section WB, and prestress is introduced by the post-tensioning method across the entire width of the structure 8 (hereafter referred to as the superstructure 8) consisting of the vertical beam sections LB, LB, precast slab 7, and cross beam section WB in the direction perpendicular to the bridge axis using PC steel members 9, 9... inserted perpendicular to the bridge axis into the superstructure 8 (deck section) consisting of the precast vertical beam members 6, 6 and precast slab 7, and PC steel members 9, 9... inserted across the entire width of the cross beam section WB in the direction perpendicular to the bridge axis.

Here, the substructure 3 is a structure erected on the ground 2 and supporting the superstructure 8, and includes the abutments on which both ends of the bridge 1 are supported, the piers located between the abutments and supporting the underside of the superstructure 8, and the multiple legs 3a, 3a and branched parts that make up the piers.

As shown in Figures 1 and 2, the pier 3 has multiple legs 3a, 3a (a pair in this embodiment) supported by a footing 3b at intervals perpendicular to the bridge axis, and the substructure cross beam 4 is supported across both legs 3a, 3a.

The substructure cross beam 4 is made of reinforced concrete or prestressed concrete and is rectangular, and is supported by each leg 3a, 3a.

This substructure cross beam 4 has a length approximately equal to the width of the bridge 1 perpendicular to the bridge axis, and is wide enough to accommodate one or more precast vertical beam members 6, 6 that are supported by the legs 3a, 3a and installed at least on both outer sides of the legs 3a, 3a and between the legs 3a, 3a.

The support member 5 is, for example, a laminated rubber support made of alternating layers of rubber material and steel plates, and its lower end is fixed to the upper surface of the substructure cross beam 4 by bolts or the like, and a girder support plate material 10 made of a steel plate or the like is fixed to its upper end.

The girder support plate material 10 is formed in a rectangular plate shape with a width that allows multiple precast vertical beam members 6, 6 (a pair in this embodiment) to be placed on it, i.e., a width that is approximately the same as or greater than the total width of the multiple precast vertical beam members 6, 6 arranged perpendicular to the bridge axis, and a thickness that ensures sufficient rigidity to support the superstructure 8 to be constructed.

In addition, although not shown, plate-shaped fixing plates protrude from the girder support plate material 10 at intervals in the direction perpendicular to the bridge axis, and the precast vertical beam members 6, 6 can be fixed to the fixing plates by bolting or the like.

As shown in FIG. 5, the precast vertical beam members 6, 6 have solid partition walls 6b, 6b at both longitudinal ends and, if necessary, in the middle, with a hollow section 6a formed between the partition walls 6b, 6b, forming a hollow rectangular parallelepiped of reinforced concrete construction.

In addition, prestress is introduced into the precast vertical beam members 6, 6 by a pretensioning method using multiple PC steel members (not shown) embedded in the longitudinal direction.

These precast vertical beam members 6, 6 are formed in accordance with standard prestressed concrete bridge girders for slabs (JIS A 5373), but by supporting the substructure cross beams 4 at a position a certain height h lower than the upper ends of the legs 3a, 3a, which are the substructure 3, when forming a deck at the same height, the height can be formed higher than that of a standard prestressed concrete bridge girders for slabs, thereby increasing the load-bearing capacity.

The precast vertical beam members 6, 6 are long enough to span multiple substructures 3 erected at intervals in the bridge axis direction, and both ends and one or more intermediate points are supported by the substructures 3 via support members 5.

The precast vertical beam members 6, 6 are provided with a precast plate support 12 that is continuous in the longitudinal direction and protrudes integrally from the upper side of the precast vertical beam members 6, 6 that constitute each vertical beam section LB, LB, on the precast plate 7 side. The precast plate support 12 supports the side edge of the precast plate 7, and the precast plate 7 is erected between each vertical beam section LB, LB.

The precast plate support 12 protrudes from the top surface of the precast vertical beam members 6, 6 at a position lower than the thickness of the side of the precast plate 7, so that when the precast plate 7 is erected between the precast vertical beam members 6, 6, the top surface of the precast plate 7 and the top surface of the precast beam member are at the same height.

The precast vertical beam members 6, 6 have numerous PC insertion holes 13, 13... formed at the top at intervals in the longitudinal direction, penetrating perpendicular to the bridge axis, which are connected to the PC insertion holes 14, 14... formed in the precast slab 7 when the precast slab 7 is erected between the two precast vertical beam members 6, 6.

In addition, in each bulkhead portion 6b, 6b... of the precast vertical beam members 6, 6, i.e., in the portion supported by the substructure cross beam 4 via the support member 5 of the precast vertical beam member 6, a plurality of PC insertion holes 15, 15... are formed at intervals in the height direction.

As shown in FIG. 6, the precast slab 7 is made of concrete and is formed into a flat plate shape, with supported convex portions 7a, 7a that are supported by the precast slab receiving portion 12 and protrude integrally from the underside of both sides.

As shown in Figure 6 (c), multiple PC steel members 17, 17... are embedded in the precast slab 7 in a tensile state in the bridge axis direction, and prestress is introduced in the bridge axis direction by the pretensioning method.

In addition, the precast slab 7 has numerous PC insertion holes 14, 14... that penetrate perpendicular to the bridge axis and are spaced apart in the bridge axis direction, and are connected to the PC insertion holes 13, 13... of the precast vertical beam members 6, 6, so that the PC steel members 9, 9... are inserted across both PC insertion holes 13, 14 over the entire width of the part (deck section) formed by the precast vertical beam members 6, 6 and the precast slab 7 in the direction perpendicular to the bridge axis.

In addition, joint reinforcing bars 16, 16 protrude from the end faces at both ends of the precast slab 7 in the bridge axis direction, and as shown in Figure 7, lap joints are formed between adjacent precast slabs 7 in the direction perpendicular to the bridge axis, and concrete is poured between the end faces to connect adjacent precast slabs 7 in the direction perpendicular to the bridge axis.

Next, the construction method of the above-mentioned bridge 1 will be explained with reference to Figures 8 and 9. In this embodiment, an example will be explained in which an existing superstructure 20 erected between substructures 3 erected at intervals in the bridge axis direction is replaced with a new superstructure 8, and the same components as in the above-mentioned embodiment will be described with the same reference numerals. In the figures, reference numeral 2 denotes the ground, and reference numeral 20 denotes the existing superstructure (hereinafter referred to as the existing superstructure 20).

The existing bridge comprises multiple substructures 3 erected at intervals in the bridge axis direction and an existing superstructure 20 erected between the multiple substructures 3, and the existing superstructure 20 is supported by each substructure 3 via existing supports 21, 21 installed on the substructures 3 such as piers.

The existing superstructure 20 is, for example, as shown in FIG. 8(a), composed of a hollow deck member having a hollow portion inside, and the hollow deck member is erected across multiple substructures 3.

To replace the existing superstructure 20 of this bridge and build a new bridge 1, first, as shown in Figure 8 (b), while leaving the existing superstructure 20 in service, construct a substructure cross beam 4 oriented perpendicular to the bridge axis at a position a specified height h lower than the upper end of the substructure 3 that supports the existing superstructure 20.

Specifically, although not shown, scaffolding is set up around the substructure 3 such as a pier, formwork is set up to match the shape of the substructure cross beam 4, and reinforcing bars are placed inside the formwork. It is preferable to integrate the reinforcing bars with the substructure 3.

Then, concrete is poured into the formwork by casting in place, and the concrete is cured and hardened to construct the substructure cross beam 4.

In this case, by constructing the substructure cross beam 4 at a position a predetermined height h lower than the upper end of the substructure 3, the existing superstructure 20 can be used during the period required to construct the substructure cross beam 4, i.e., during the series of tasks of setting up scaffolding, setting up formwork, arranging rebar, pouring concrete, curing and hardening the concrete, and stripping the form, and social losses such as traffic restrictions can be minimized.

Next, once the substructure cross beam 4 has been constructed, the existing superstructure 20 is taken out of service, as shown in FIG. 8(c), and the existing superstructure 20 is divided into predetermined intervals, after which each divided section of the existing superstructure 20 is removed using girders and a crane (not shown).

Next, as shown in FIG. 9(d), support members 5 are attached to both sides of the substructure cross beam 4, sandwiching the legs 3a, 3a of the lower structure 3, i.e., to the outside of the legs 3a, 3a on the substructure cross beam 4 and between the legs 3a, 3a. The girder support plate material 10 is fixed to the upper end of the support member 5, and both ends of the girder support plate material 10 perpendicular to the bridge axis are supported by the substructure cross beam 4 via temporary support members 22, 22.

Then, two precast vertical beam members 6, 6 are placed on the girder support plate material 10 in a line perpendicular to the bridge axis to form the vertical beam sections LB, LB, and the predetermined positions of each precast vertical beam member 6, 6 are fixed to the girder support plate material 10.

In addition, among the precast vertical beam members 6, 6 that make up the vertical beam sections LB, LB, the one that is placed on the precast slab 7 side is equipped with a precast slab support part 12 on the upper side on the precast slab 7 side.

In this state, the vertical beam sections LB, LB are not supported by each other, but both ends of the girder support plate material 10 perpendicular to the bridge axis are supported by the substructure cross beams 4 via temporary support members 22, 22, so that the precast vertical beam members 6, 6 are supported by each substructure 3 in a stable state.

Next, as shown in FIG. 9(e), precast slabs 7 are erected between adjacent vertical beam sections LB, LB spaced apart perpendicular to the bridge axis, and multiple precast slabs 7 are laid in the bridge axis direction.

As shown in Figure 7, joint reinforcing bars 16, 16 protruding from the end faces of each precast slab 7 are placed in an overlapping state between the precast slabs 7 connected in the bridge axis direction to form lap joints, and mortar or concrete is poured between the precast slabs 7 to connect them.

Although not specifically shown, the PC insertion holes 13, 13 of the precast vertical beam members 6, 6 and the precast slabs 7, which are continuous in the direction perpendicular to the bridge axis, are connected by sheaths.

Next, as shown in FIG. 9(f), a formwork is installed to close the area surrounded by the vertical beams LB, LB (precast vertical beam members 6, 6) on the substructure cross beam 4 and the precast slab 7, reinforcing bars and sheaths are placed inside the formwork as necessary, and then concrete 23 is poured in place to form the horizontal beams WB.

In addition, the gaps between the adjacent precast vertical beam members 6, 6 and the gaps between the precast vertical beam members 6, 6 and the precast slab 7 are filled with a filler such as mortar.

Then, as shown in FIG. 10(g), PC steel members 9, 9... are inserted across the entire width of the deck section, consisting of the precast vertical beam members 6, 6 and the precast slab 7, perpendicular to the bridge axis, and PC steel members 9, 9... are inserted across the entire width of the cross beam section WB, perpendicular to the bridge axis. With these PC steel members 9, 9... under tension, both ends are fixed to both sides of the structure (superstructure 8) consisting of the vertical beam sections LB, LB, the precast slab 7 and the cross beam section WB, and prestress is introduced by the post-tensioning method across the entire width of the superstructure 8, perpendicular to the bridge axis.

After the prestress is introduced, as shown in Figure 10 (h), the temporary support members 22, 22 are removed and the superstructure 8 is supported only by the support members 5, and side walls 24, 24, etc. are installed as necessary to complete the construction of the bridge 1.

In the above embodiment, the case where the existing superstructure 20 is replaced with a new superstructure 8 has been described, but after constructing the substructure 3, the substructure cross beams 4 can be constructed, and then a new bridge 1 can be constructed by carrying out the work in the same manner as shown in Figures 8(c) to 10(h).

In this case, the substructure cross beam 4 does not necessarily need to be supported at a position a certain height h lower than the upper end of the substructure 3 (legs 3a, 3a). It may be constructed so that the upper surface of the substructure 3 and the upper surface of the substructure cross beam 4 are flush with each other across the upper end of the substructure 3, or the substructure cross beam 4 may be formed in a state where it is erected on the substructure 3.

Reference Signs List 1 Bridge 2 Ground 3 Substructure 4 Substructure cross beam 5 Support member 6 Precast vertical beam member 7 Precast slab 8 Superstructure 9 PC steel 10 Girder support plate material 11 Fixed plate 12 Precast slab support part 13-15 PC insertion hole 16 Joint reinforcing bar 17 PC steel 20 Existing superstructure 21 Existing support body 22 Temporary support member 23 Concrete 24 Side wall LB Vertical beam part WB Horizontal beam part

Claims (7)

In a bridge in which a superstructure is erected between substructures spaced apart in the bridge axis direction,
A substructure cross beam supported on the upper part of each of the substructures in a direction perpendicular to the bridge axis;
A vertical beam portion made of one or more hollow rectangular parallelepiped precast vertical beam members oriented in the bridge axis direction and supported on the substructure cross beam via bearing members;
A precast plate is installed between adjacent vertical beam portions spaced apart in a direction perpendicular to the bridge axis,
A cross beam portion is formed by filling a portion surrounded by the adjacent vertical beam portions and the precast plate with concrete on the substructure cross beam,
A bridge characterized in that prestress is introduced by the post-tensioning method across the entire width perpendicular to the bridge axis of the structure consisting of the vertical beam members, the precast plate and the horizontal beam members, by PC steel members inserted across the entire width perpendicular to the bridge axis of the deck section consisting of the precast vertical beam members and the precast plate, and PC steel members inserted across the entire width perpendicular to the bridge axis of the horizontal beam members. The bridge according to claim 1, in which the substructure cross beam is supported at a position a predetermined height lower than the upper end of the substructure. A bridge as described in claim 1 or 2, in which prestress is introduced to the precast slab by pretensioning using PC steel members oriented in the bridge axis direction. A method for constructing a bridge in which a superstructure is erected between substructures spaced apart in the bridge axis direction, comprising:
A substructure cross beam perpendicular to the bridge axis is supported on the upper part of each of the substructures,
One or more hollow rectangular parallelepiped precast vertical beam members oriented in the bridge axis direction are supported on the substructure cross beam via bearing members to form a vertical beam portion;
Then, a precast plate is erected between adjacent vertical beams spaced apart in the direction perpendicular to the bridge axis,
Pour concrete into a portion surrounded by the adjacent vertical beam portions and the precast slabs at an interval on the substructure horizontal beam to form a horizontal beam portion;
The PC steel is inserted along the entire width of the deck section consisting of the precast vertical beam member and the precast slab in the direction perpendicular to the bridge axis, and the PC steel is inserted along the entire width of the cross beam section in the direction perpendicular to the bridge axis,
A bridge construction method characterized in that prestress is introduced by the post-tensioning method using the PC steel material across the entire width perpendicular to the bridge axis of the structure consisting of the vertical beam section, the precast plate, and the horizontal beam section. A bridge construction method in which an existing superstructure is replaced with a new superstructure between substructures erected at intervals in the bridge axis direction,
A substructure cross beam is constructed in advance at a position a predetermined distance lower than the upper end of the substructure supporting the existing superstructure, and is oriented perpendicular to the bridge axis.
After removing the existing superstructure,
A vertical beam portion is formed by supporting one or more hollow rectangular parallelepiped precast vertical beam members oriented in the bridge axis direction via bearing members on both sides of the upper end portion of the lower structure of the substructure cross beam,
Thereafter, a precast plate is erected between the adjacent vertical beam portions with a gap therebetween, sandwiching the upper end portion of the lower structure therebetween;
Pour concrete into a portion surrounded by the adjacent vertical beam portions and the precast slabs at an interval on the substructure horizontal beam to form a horizontal beam portion;
The PC steel is inserted along the entire width of the deck section consisting of the precast vertical beam member and the precast slab in the direction perpendicular to the bridge axis, and the PC steel is inserted along the entire width of the cross beam section in the direction perpendicular to the bridge axis,
A bridge construction method characterized in that prestress is introduced by the post-tensioning method using the PC steel material across the entire width perpendicular to the bridge axis of the structure consisting of the vertical beam section, the precast plate, and the horizontal beam section. With both ends of the girder support plate material installed on the support member in the direction perpendicular to the bridge axis supported by the substructure cross beam via temporary support members, a plurality of the precast vertical beam members are installed on the girder support plate material in a line perpendicular to the bridge axis;
6. A bridge construction method as described in claim 4 or 5, wherein prestress is introduced by the post-tensioning method using the PC steel material across the entire width perpendicular to the bridge axis of the structure consisting of the vertical beam section, the precast plate and the horizontal beam section, and then the temporary support member is removed. The bridge construction method according to claim 4 or 5, in which prestress is introduced into the precast slab by pretensioning with PC steel members oriented in the bridge axis direction.

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