JP2007205139A - Construction method of arch bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a construction cost and to shorten a construction period by efficiently constructing posts erected on an arch rib, and a deck girder supported on the posts in a method of constructing an arch bridge by a lowering method. <P>SOLUTION: Rotary bearings 8 are provided respectively on two arch abutments 1 provided in facing positions, and arch ribs (half arches) 2' are placed thereon to rise upward. Steel members 41 constituting the whole or a part of the deck girder, and post members 31 connecting the steel members to the arch ribs, are mounted. At this time, the lower ends of the steel members are fixed onto the ground to support the steel members and the arch ribs in a stable state. The half arches with the arch ribs rising to a predetermined height are rotated together with the steel members and post members to lower the upper parts in a direction to face each other while being supported by primary cables 13 or secondary cables 14, and joined in the facing position of the tips of the half arches to close the arch ribs to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The invention according to the present application is constructed so as to rise upward on an arch abut that faces almost half of the arch rib (hereinafter referred to as half arch) of the entire arch to be constructed, and the formed half arch is rotated to the opposite side. It is related to the construction method of the arch bridge that connects the two at the center.

  One method of constructing a large-scale concrete arch bridge is to build up half arches on the facing arch abutment, and rotate these half arches to the opposite sides to face each other. There is a so-called lowering method that connects two half arches. In this construction method, machines and equipment for constructing the arch abutment can be provided in a concentrated manner around the arch abutment, and work efficiency can be improved. In addition, since the weight of the half arch being installed is transmitted to the arch abutment as an axial force, the bending moment generated in the half arch and the rotation moment (falling moment) of the half arch are reduced, and the half arch is unstable in a cantilevered manner. It is possible to extremely shorten the period of suspension support in a simple state. Therefore, it is possible to perform safe construction, shorten the construction period, and reduce the construction cost as compared with the construction method in which the arch rib is erected in a cantilever manner.

Patent Document 1 discloses a construction method in which two lowering cables of a primary cable and a secondary cable are stretched between a half arch and an anchor block and the half arch is rotated in a stable state.
In this method, as shown in FIG. 10, arch ribs 102 are constructed by sequentially placing concrete on the two arch abutments 101 facing each other. The primary cable 103 is stretched between the arch rib 102 and the anchor block 104. The arch rib 102 is supported by pushing the extruded jack 105 against the center of the span, and the arch rib 102 is pushed to the jack side by the pulling force of the primary cable 103 to firmly support the arch rib 102 being constructed. To do.

Further, the arch rib 102 is raised upward, and when the construction is completed to the half of the entire length of the arch rib, the secondary cable 106 is arranged between the vicinity 102a of the half arch 102 and the anchor block 104, and the extrusion jack 105 is half-finished. The arch is fed forward and the primary cable 103 is gradually fed out. As a result, the half arch is rotated around the rotation support 107 and is inclined in a direction opposite to each other. When the inclination of the half arch advances and the rotational moment increases, the tensile force of the secondary cable 106 is adjusted to resist the rotational moment of the half arch while adjusting the length of the secondary cable 106. As described above, by appropriately maintaining the respective stress levels using the primary cable 103 and the secondary cable 106, the influence of the sag of the cable can be reduced and the half arch can be supported in a stable state. Then, by gradually sending out the secondary cable 106, the half arch is rotated to a predetermined angle, and the opposed half arch is closed at the center of the span. After that, a support work is assembled on the closed arch rib, and a column supporting the upper girder is erected and the upper girder is constructed to complete the arch bridge.
JP 2003-321805 A

  However, in the lowering method as described above, after the arch rib is installed, a support work is provided on the arch rib to construct the support column and the upper girder supported by the support column. It is desired to shorten this. In addition, a large lifting device is required to transport the materials for constructing the columns and the upper girders on the support work, and much time and cost are required.

  The invention according to the present application has been made in view of the circumstances as described above. The purpose of the invention is to efficiently construct an upper girder and a supporting column supporting the same in a method for constructing an arch bridge by lowering, thereby reducing costs. And shortening the construction period.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that an arch abutment is formed on both sides of a confronting bridge point, and the entire arch is constructed on a rotation support provided on each of the arch abutments. The half arch ribs (hereinafter referred to as half arches) are constructed so as to rise upward, and the two half arches facing each other are rotated to a predetermined angle on the opposite sides to connect the two half arches. In the construction method of the arch bridge, a steel member that rises above the half arch on the rotary bearing and that is a part or all of the upper girder supported on the arch rib after being connected, and the steel member A plurality of column members to be supported on the arch ribs are attached to predetermined positions of the half arch, and the half arches to which the column members and the steel members are attached are opposed to each other. Rotates to a predetermined angle side, there is provided a method for constructing a arch bridge, which comprises coupling a semi arch and steel members at span center.

  In this method, since the steel member that becomes all or part of the upper beam and the plurality of column members for supporting the steel member on the arch rib are attached at predetermined positions when the half arch is constructed upward, When the half arches are connected and the arch ribs are installed between the two arch abuts, part or all of the column members and the upper girder are already mounted on the arch ribs. And the support | pillar which supports an upper road girder and an upper road girder can be constructed | assembled using this pillar member and a steel member. As a result, the scaffolding and supporting work for constructing the column member and the upper girder can be simplified, and the amount of material conveyed onto the span after the arch rib is installed is reduced. Therefore, the work efficiency can be improved and the period for constructing the upper girder and the support can be greatly shortened. Moreover, when starting up while constructing the half arch, the construction of the arch rib and the attachment of the column member and the steel member can be performed in parallel, and the period for constructing the half arch is not significantly extended.

  On the other hand, since the steel member and the column member are attached in the vicinity of the arch abutment, a facility such as a crane may be provided in the vicinity of the arch abutment, which can be simplified. In addition, since the column member and steel member rotated integrally with the half arch are lightweight, even if the half arch rotates and the half arch overhangs in a cantilevered state, the half arch rotation moment Can be prevented from becoming excessive.

  The invention according to claim 2 is the construction method of the arch bridge according to claim 1, wherein the column member is made of steel, and the two half arches facing each other are connected at the center of the span, and then the concrete is It shall be rolled up.

  In this method, the column member is made of only steel until the opposing half arches are connected, so the weight of the column member is kept small and the steel member is supported by the column member having sufficient strength and rigidity. can do. As a result, even when the half arch rotates downward and protrudes greatly toward the span, the increase in rotational moment can be suppressed and the steel member serving as the upper girder is supported at a predetermined position. Moreover, since concrete is wound up on the column member made of steel after the half arch is closed, it has sufficient rigidity and strength to support the upper girder.

  The invention according to claim 3 is the construction method of the arch bridge according to claim 1 or 2, wherein the steel member has a truss structure, and after the arch rib is connected, concrete is placed and the floor is placed. A plate is formed to form an upper girder that is a composite structure with a steel member.

In this method, since the upper girder has a composite structure including a steel truss and a concrete floor slab, the weight can be significantly reduced as compared with a concrete structure. Further, until the half arch is closed at the center, only the steel member of the truss structure is attached to the half arch, and this steel truss can be light and have high rigidity. Therefore, even in the step of rotating the half arch to which the steel member is attached to a predetermined angle, an increase in the rotational moment is suppressed, and a large cross-sectional force is not generated on the column member or the steel member on the half arch.
In addition, after installing the arch ribs between the arch abuts, the concrete of the floor slab can be placed in a state supported by the steel truss, and a composite structure with the concrete floor slab can be formed, and the work efficiency is remarkably improved. The period can be shortened.

  According to a fourth aspect of the present invention, in the method for constructing an arch bridge according to the first, third, or fourth aspect, the half arch is supported while being raised on the arch abutment. The lower end of the steel member is fixed to a pedestal provided behind the arch abutment.

  In this method, since the lower end of the steel member is fixed to the pedestal on the ground, the steel member can be assembled in a stable state, and the stability of the half arch raised on the arch abutment is also ensured. be able to.

  The invention according to claim 5 is the construction method of the arch bridge according to any one of claims 1 to 4, wherein when the half arch is rotated and inclined, the lower arch for supporting the half arch is provided. At least a part of the cable is fixed at one end to the upper part of the half arch raised above the arch abut, and the top part is arched when the half arch is connected to the axis of the column member. An intermediate portion is locked near the top of the temporary support column, which is higher than the height of the crown, and the other end is locked to an anchor block fixed to the ground behind the arch abutment.

  In this method, the lowering cable locked in the vicinity of the head of the column member is located far away from the center of rotation of the half arch, that is, the position of the rotation support, even if the half arch protrudes greatly toward the support. Can be stretched. Therefore, even if the tension of the lowering cable is small, it is possible to resist a large rotational moment of the half arch. As a result, it is possible to reduce the burden on the anchor block that grasps the lowering cable and gradually sends it out, and the half arch can be rotated in a stable state to a predetermined angle.

  As described above, in the construction method of the arch bridge according to the present invention, the half arch is raised on the arch abutment, and the steel member serving as the upper girder and the column member that supports the steel member on the arch rib are attached to the arch rib. Then, this half arch is constructed by rotating it to a predetermined angle. Therefore, after the arch ribs are installed, the support girder for constructing the upper girder and the column supporting the upper girder is remarkably reduced, and the work period can be shortened by performing the work efficiently. Further, it is possible to suppress an increase in rotational moment that occurs when the half arch rotates by suppressing the weight of the member that is attached to the half arch and rotated as a unit.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic side view showing an example of an arch bridge that can be installed by the method according to the present invention and a cross-sectional view taken along the line AA in the figure.
The arch bridge includes an arch rib 2 installed between two arch abutments 1a and 1b provided to face both sides of the bridge point, a plurality of support columns 3 installed on the arch rib 2, A main part is composed of an upper road girder 4 supported by a column 3 and on which a road surface is formed.

The upper girder 4 is a composite structure composed of a truss-like steel member 41 and a concrete floor slab 42, and is supported above the arch rib 2 by a column 3 raised from the arch rib. Further, on both sides, the bridge piers 5a and 5b raised on the arch abut 1 and the piers 6a and 6b raised on the ground are supported, and both ends thereof are supported by the abutments 7a and 7b.
The column 3 raised on the arch rib 2 is a composite member of a column member 31 made of a steel pipe and a reinforced concrete 32 wound up so as to be in close contact with the outer peripheral surface thereof. To be joined. As a structure of the joint portion, a structure capable of transmitting a bending moment or a structure not transmitting a bending moment can be appropriately selected. .

The arch rib 2 is made of reinforced concrete and is a fixed arch whose both ends are fixed to a pair of arch abutments 1a and 1b. The two arch members 21a and 21b are arranged side by side in the width direction, and are connected to each other by a cross member 22 made of concrete. Thereby, the arch rib 2 has a big resistance force also with respect to the horizontal force of a horizontal direction.
Further, the arch rib 2 is formed so that a half arch, which is substantially half of the whole arch rib, is formed so as to rise substantially vertically on the arch abuts 1a and 1b, and the arch ribs 2 are formed so as to face each other around the lower end of the half arch. It is formed by connecting the tips of both half arches facing each other to rotate downward.

Next, the construction method of the arch bridge will be described with reference to the drawings.
As shown in FIG. 2, an abutment 7 is provided at a position that supports the end of the upper beam girder 4, and an arch abut 1 that supports the arch rib 2 is constructed in front of the abutment 7. The abutment 7 also serves as an anchor block for the cable that supports the arch ribs being installed, and is firmly fixed to the ground or rock by a ground anchor (not shown). In addition, the pier 6 is erected at a predetermined position on the ground. Next, on the arch abut 1, a rotary bearing 8 serving as a base of the half arch is installed, and an arch rib (half arch) 2 ′ is formed to rise upward so as to be continuous with the rotary bearing 8. The arch rib 2 'is constructed by dividing concrete into blocks of a predetermined length and sequentially placing concrete on site.

  The rotary support 8 is disposed at a position for supporting two arch members 21a and 21b arranged in parallel in the width direction of the arch rib 2 ', and has a lower collar 8a fixed to the arch abut 1 and an arch member 21a, It is comprised with the upper collar 8b fixed to the lower end part of 21b. The lower rod 8a and the upper rod 8b can be rotated around an axis in the horizontal direction.

  The arch rib 2 ′ formed so as to be fixed to the upper collar 8 b of the rotary bearing 8 is provided with a temporary support 9 provided on the arch abut 1 and a reaction force received between the temporary support 9 and the abutment 7. It is supported by a temporary fixing jack 11 or an extrusion jack 12 supported by the beam 10. That is, while the height of the arch rib 2 ′ under construction is low, it is supported by the temporary fixing jack 11 as shown in FIG. 2, and when the arch rib 2 ′ is raised to almost the same height as the bridge surface, FIG. As shown, the extrusion jack 12 supports the arch rib 2 'being built. Further, the arch rib 2 'is formed to be inclined slightly rearward, that is, in a direction in which the temporary fixing jack 11 or the push-out jack 12 is provided, and prevents the forward falling moment from acting.

  When the arch rib 2 'is raised to almost the same height as the bridge surface, as shown in FIG. 3, the primary cable 13 is disposed between the arch rib 2' and the abutment 7 which is an anchor block. The arch rib 2 ′ is pushed out against the jack 11 by tension. As a result, the arch rib 2 'is supported in a stable state and prevented from tipping forward.

  As the arch rib 2 ′ is raised, as shown in FIG. 3, the column member 31 constituting the column 3 is attached on the arch rib 2 ′. As shown in FIG. 4, the column member 31 is erected on the two arch members 21 a and 21 b, and supports a steel member 41 that is a part of the upper girder at the head. Further, the position where the column member 31 is provided is appropriately set so that the span length of the upper beam 2 is appropriately divided and the cross-sectional force generated in the arch rib 3 is suppressed to a small level.

When the column member 31 is attached to the arch rib 2 ′ being constructed, a truss-shaped steel member 41 that is a part of the upper beam 2 is connected to the vicinity of the top of the column member 31. As shown in FIGS. 3 and 4, the steel member 41 forms a three-dimensional truss composed of an upper chord member 41a, a lower chord member 41b, and a diagonal member 41c. The upper chord member 41a and the lower chord member 41b are formed of steel pipes, and a steel pipe or a steel mold member can be used for the diagonal member 41c.
The steel member 41 having the truss structure is manufactured at a factory as a block having a predetermined length. Then, each block is suspended and supported by a crane or the like on the site, and is raised upward while being joined to the head of the column member 31. As shown in FIG. 3, the lower end of the steel member 41 is fixed on the footing 6 a of the bridge pier 6 provided on the ground behind the arch abut 1. Thereby, the steel member 41 and arch rib 2 'which stand | start up upwards can be supported in the stable state.

A step of attaching the column member 31 to a predetermined position while sequentially raising the arch rib 2 'upward, and a step of connecting the steel member 41 to the head of the column member 31 and joining the steel member 41 raised previously. Repeatingly, as shown in FIG. 5, the half arch in which the arch rib 2 'is formed to a predetermined height is completed.
Then, the secondary cable 14 is disposed between the upper part of the half arch 2 ′ and the anchor block 7. No tension is introduced into the secondary cable 14 when it is placed, and the half arch is supported by the primary cable 13 and the push-out jack 12.

The half arches are rotated so as to lower the upper end portion in the direction facing each other, that is, in the direction of arrow B shown in FIG.
The lower end portion of the steel member 41 fixed on the footing 6c is released, and the push-out jack 12 is pushed forward (center side of the span), and the primary cable 13 is slowly fed out on the abutment 7 side. As a result, the half arch 2 ′ is gradually rotated around the rotation support 8 and inclined toward the center of the span. When the rotation of the half arch 2 ′ advances by a predetermined amount, the half arch 2 ′ protrudes from the arch abut 1 and the rotational moment increases. When tilted to a predetermined angle, tension is introduced into the secondary cable 14, resists the increased rotational moment by the tension of the secondary cable 14, and the secondary cable 14 is sent out little by little to send the half arch 2 '. Is rotated to a predetermined angle.

  As shown in FIG. 6, when a pair of opposing half arches 2'a and 2'b are arranged at predetermined positions so as to abut each other, the tip surfaces of both half arches 2'a and 2'b A reinforcing bar is placed between the two and concrete is placed to form an arch crown portion 2c, and a closed arch rib 2 is formed. Thereafter, the rotary bearing 8 is embedded with concrete so that the lower end of the arch rib 2 is continuous with the arch abut 1 and is a fixed arch at both ends.

  On the other hand, a reinforcing bar is arranged around the column member 31 standing on the arch rib 2 and a mold is assembled, and concrete is wound up to form a composite member of the column member 31 and the surrounding concrete 32. Thereby, sufficient strength and rigidity for supporting the upper girder 2 are secured. On the arch abut 1, the temporary support column 9 and the reaction force receiving beam 10 are removed, and the pier 5 (not shown in FIG. 6) is erected. Then, a steel member (not shown in FIG. 6) that is continuous with the truss-shaped steel member 41 that is mounted almost horizontally on the arch rib 2 and reaches the abutment 7 is mounted. A formwork is assembled on the steel member 41 forming the three-dimensional truss, and concrete of the floor slab 42 is placed so as to be integrated with the steel member 41, thereby completing the arch bridge.

7, 8 and 9 are schematic views showing a method for constructing an arch bridge which is an embodiment of the invention according to claim 5.
In this method, as shown in FIG. 7, when the construction of the half arch 52 'is almost completed, the secondary cable 61 is arranged between the abutment 57 serving as an anchor block and the upper part of the half arch 52'. Further, among the plurality of column members (steel pipes) 62 that are attached to the half arch 52 ′ and that constitute the support column, the column member 62 that is attached at a position closest to the arch abutment 51 has a top portion 62a thereof from the arch crown portion. Is provided so as to protrude upward from the joint with the steel member 63 so as to be higher.
The step of constructing the half arch 52 ′ can be performed in the same manner as the arch bridge shown in FIGS.

  Thereafter, the half arch 52 'is pushed out by the push-out jack 64, and the primary cable 65 is slowly fed out to gradually rotate the half arch 52' and tilt it toward the span. When the rotation of the half arch 52 ′ proceeds to a predetermined angle, a tension is introduced into the secondary cable 61, and the half arch 52 ′ is supported by the tension of the secondary cable 61. Then, when the rotation of the half arch 52 ′ further proceeds, the secondary cable 61 is locked to the top portion 62a of the column member extended upward, and the above-mentioned from the upper part of the half arch 52 ′ as shown in FIG. The column member 62 is bent at the top 62 a and the other end is locked to the abutment 57. The secondary cable 61 stretched in this way has its axis line away from the rotation support 58 as shown in FIG. It becomes possible to resist the rotational moment of the arch 52 '. Thereby, the tensile force borne by the abutment 57 functioning as an anchor block can be reduced, and the half arch 52 'before closing can be supported in a stable state. In this way, the secondary cable 61 supports the half arch 52 'while rotating it to a predetermined position and supports the end faces of both half arches 52'a and 52'b as shown in FIG. . Then, reinforcing bars are arranged between the end faces of both half arches 52 ′ a and 52 ′ b, and concrete is placed to close the arch ribs 52. The steps after the half arches 52'a and 52'b are closed can be performed in the same manner as the construction of the arch bridge shown in FIGS.

  The arch bridge construction method described above is an upper arch bridge in which the upper road girder is higher than the arch rib. However, in contrast to the so-called middle road arch bridge in which the upper girder is partly below the arch rib. It is possible to apply.

It is the schematic side view which shows an example of the arch bridge which can be constructed by the method concerning this invention, and sectional drawing in the AA line in a figure. It is a side view which shows the state under construction of the arch bridge shown in FIG. It is a side view which shows the state under construction of the arch bridge shown in FIG. It is sectional drawing in the middle of construction of the arch bridge shown in FIG. It is a side view which shows the state under construction of the arch bridge shown in FIG. FIG. 2 is a side view showing a state in which the arch bridge shown in FIG. 1 is being constructed and the half arch has finished rotating. It is a side view which shows the other construction method of the arch bridge shown in FIG. It is a side view which shows the other construction method of the arch bridge shown in FIG. It is a side view which shows the state which rotation of the half arch was completed by the other construction method of the arch bridge shown in FIG. It is the schematic which shows the conventional lowering construction method.

Explanation of symbols

1: Arch abut, 2: Arch rib, 2 ': Arch rib under construction, 3: Post, 4: Upper girder, 5: Bridge pier, 6: Bridge pier, 6c: Foot pier footing, 7: Abutment (anchor block), 8: Rotating bearing, 8a: Lower arm, 8b: Upper arm, 9: Temporary strut, 10: Reaction force receiving beam, 11: Jack for temporary fixing, 12: Push-out jack, 13: Primary cable (lowering cable), 14: Secondary Cable (lowering cable),
21a, 21b: Arch member, 2c: Arch crown part, 22: Cross member,
31: Column member made of steel pipe, 32: Reinforced concrete,
41: Steel member, 41a: Upper chord material, 41b: Lower chord material, 41c: Diagonal material, 42: Concrete floor slab,
51: Arch abut, 52 ': Arch rib under construction, 56: Pier, 57: Abutment (anchor block), 58: Rotating support, 59: Temporary support, 60: Reaction force receiving beam,
61: Primary cable (lowering cable), 62: Column member (steel pipe), 62a: Top of column member, 63: Steel member, 64: Extruded jack, 65: Secondary cable (lowering cable),

Claims (5)

Form an arch abut on both sides of the opposite bridge,
It is constructed so that almost half arch ribs (hereinafter referred to as half arches) of the entire arch to be constructed are raised upward on the rotary bearing provided on each of the arch abuts,
In the construction method of the arch bridge that rotates the two half arches facing each other to a predetermined angle on the facing side, and connects the two half arches,
The half arch is raised upward on the rotating bearing, and the steel member which becomes all or part of the upper beam supported on the arch rib after being connected, and the steel member for supporting the steel member on the arch rib Attach a plurality of pillar members to a predetermined location of the half arch,
A method for constructing an arch bridge, wherein the half arch to which the column member and the steel member are attached is rotated to a predetermined angle on the side facing each other, and the half arch and the steel member are connected at the center of the span.   The method for constructing an arch bridge according to claim 1, wherein the column member is made of steel, and concrete is wound up after two opposing half arches are connected at the center of the span.   The steel member has a truss structure, and after the arch ribs are connected, concrete is cast to form a floor slab and an upper road girder that is a composite structure with the steel member is formed. Or the construction method of the arch bridge of Claim 2.   The lower end of the steel member is fixed to a pedestal provided at the rear of the arch abut while the half arch is supported while being raised on the arch abut. The construction method of the arch bridge of Claim 1, Claim 2 or Claim 3. When the half arch is rotated and inclined, at least a part of the lowering cable for supporting the half arch is:
One end is fixed to the upper part of the half arch raised above the arch abut,
Near the top of the temporary strut, where the top is positioned higher than the height of the arch crown when the half arch is connected on the axis of the column member,
The construction method of the arch bridge according to any one of claims 1 to 4, wherein the other end is locked to an anchor block fixed to a ground behind the arch abutment.

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