JP2014005685A - Method for constructing box girder bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve rapid construction regardless of the structure of each of the webs constituting a part of a box girder, in a method for constructing a box girder bridge by overhang construction work.SOLUTION: In a state that a movable work vehicle 100 is moved to an upper floor slab 12 constituting a leading block B(n) with an unconstructed lower floor slab 14, construction of webs 16 in a next leading block B(n+1) is carried out. After that, construction of the upper floor slab 12 of the next leading block B(n+1) and the lower floor slab 14 of the leading block B(n) is carried out. At this time, construction of webs 16 in the next leading block B(n+1) is performed by inserting a PC steel 26 through two panel members 22 to constitute the webs 16 and two upper precast ribs 24 to constitute a part of the upper floor slab 12 in the bridge axial direction and applying tension to them, in the state that the panel members 22 and the upper precast ribs 24 are suspended and supported by the movable work vehicle 100 and arranged alternately in the bridge axial direction.

Description

  The present invention relates to a method for constructing a box girder bridge by overhanging construction.

  As described in, for example, “Patent Document 1” to “Patent Document 3”, the box girder bridge forms a box-shaped cross section with an upper floor slab, a lower floor slab, and a plurality of webs connecting them. It has a main girder structure extending in the direction of the bridge axis.

  In that case, the box girder described in “Patent Document 2” has each web formed of a plurality of panel members. Moreover, as for the box girder described in "patent document 3," each web is comprised by the corrugated steel web.

  And "patent document 3" describes the method of constructing such a box girder bridge for every block of predetermined length by overhang construction using a mobile work vehicle.

  In the erection method described in “Patent Document 3”, the corrugated steel web of the next topmost block is pre-constructed with the upper floor slab moving the moving work vehicle to the unconstructed top block. Thereafter, the lower floor slab of the topmost block and the upper floor slab of the top block are constructed at the same time in a state where the moving work vehicle is moved to the corrugated steel web that has been previously constructed.

JP 2001-49616 A JP 2002-220812 A Japanese Patent Laid-Open No. 2004-116059

  By adopting the erection method as described in the above-mentioned “Patent Document 3”, it is possible to realize rapid construction, thereby shortening the construction period.

  However, depending on the structure of the web that forms part of the box girder, due to its strength, there is a problem that the mobile work vehicle cannot be moved to the web that has been previously constructed, and thus rapid construction cannot be realized. is there.

  The present invention has been made in view of such circumstances, and in the method of laying a box girder bridge by overhanging construction, realizes rapid construction regardless of the structure of each web constituting a part of the box girder. The purpose is to provide a method for erection of a box girder bridge.

  The present invention is intended to achieve the above object by devising the construction method of each web.

That is, the box girder bridge construction method according to the present invention is
Box girder bridges extending in the direction of the bridge axis by forming a box-shaped cross section with the upper floor slab, the lower floor slab, and a plurality of webs connecting them, for each block of a predetermined length by overhang construction using a mobile work vehicle In the method of erection,
After constructing each web in the topmost block next to the top block, with the mobile work vehicle moved to the top floor slab where the bottom floor slab constitutes the top block not yet constructed, Work on the upper floor slab and the lower floor slab of the top block,
At that time, the construction of each of the webs in the topmost block is carried out by using the mobile work vehicle with at least one panel member that should constitute the web and at least one upper precast rib that should constitute a part of the upper floor slab. In a state where the steel plate is suspended and alternately arranged in the bridge axis direction, the PC steel material is inserted into the bridge axis direction to be tensioned with respect to these, and is tensioned.

  In the above-mentioned aspect of “the PC steel material is inserted and tensioned in the bridge axis direction against these”, the PC steel material is inserted and tensioned in the bridge axis direction with respect to both the upper precast ribs and the panel members. And a mode in which the PC steel material is inserted in the direction of the bridge axis and is tensioned only with respect to each upper precast rib.

  As shown in the above configuration, in the present invention, after the construction of each web in the topmost block in the state where the lower floor slab has moved the moving work vehicle to the upper floor slab constituting the unconstructed top block, Construction of the upper floor slab of the topmost block and the lower floor slab of the top block is carried out. At that time, construction of each web in the topmost block is made up of at least one panel member and the upper floor to constitute the web. At least one upper precast rib that should constitute a part of the plate is suspended and supported by a moving work vehicle and alternately arranged in the bridge axis direction. By doing so, the following effects can be obtained.

  That is, by using the at least one panel member and the at least one upper precast rib to perform each web of the topmost block in advance, the top floor slab of the topmost block can be easily constructed. In addition, the construction of the lower floor slab of the top block can be easily performed by using the already constructed webs. For this reason, the upper floor slab of the top block and the lower floor slab of the top block can be constructed simultaneously without moving the mobile work vehicle to the top block.

  Therefore, according to the present invention, in the method of laying the box girder bridge by overhanging construction, rapid construction can be realized regardless of the structure of the web constituting a part of the box girder.

  In the above configuration, if two PC steel materials are arranged on both sides of at least one panel member, and each PC steel material is inserted into at least one upper precast rib, the PC steel material is inserted into each panel member. The need to form holes can be eliminated, and the configuration can be simplified.

  In the above configuration, if the shape of each panel member is set so that the panel members adjacent in the bridge axis direction are in contact with each other at the lower end portion of the panel member, the bridge between the panel members is provided. It is possible to efficiently transmit the axial compressive force.

  Alternatively, in the above configuration, when each web in the topmost block is constructed, at least one panel member that constitutes the web and at least one lower precast rib that constitutes a part of the lower floor slab are bridge shafts. If the PC steel materials are inserted in the direction of the bridge axis in such a manner that they are alternately arranged in the direction of the bridge axis, the following operational effects can be obtained.

  That is, by performing tension of the PC steel material at the upper and lower end portions of each web, the stability of each panel member at the time of construction of each web in the topmost block can be improved, and the lateral collapse or the like occurs. The fear can be effectively suppressed.

  In addition, it is possible to easily perform the operation of adjusting the orientation of the panel member using a turnbuckle or the like after the construction of each web in the topmost block.

  Furthermore, for the construction of the lower floor slab in the top block, after laying a precast plate between the lower precast ribs adjacent in the bridge axis direction, the lower floor slab concrete is placed using the lower precast rib and the precast plate as an embedded formwork. By doing so, it is also possible to perform it. And by doing in this way, the assembly work of a formwork can be simplified significantly and the construction efficiency of a lower floor slab can be raised by this.

  In the above configuration, if each panel member and each upper precast rib are brought into contact with each other on the concavo-convex surface, positioning within the bridge axis orthogonal plane between them can be achieved and a function as a shear key can be achieved. it can.

  In the above configuration, in the construction of the upper floor slab in the topmost block, after laying a precast plate between the upper precast ribs adjacent in the bridge axis direction, the upper floor slab concrete is cast using the upper precast rib and the precast plate as an embedded formwork. If it is carried out by installing, the assembling work of the mold can be greatly simplified, and thereby the construction efficiency of the upper floor slab can be increased.

  In addition, by doing this, when constructing the upper floor slab of the topmost block, it is possible to prevent the load of the upper floor slab concrete from acting on the mobile work vehicle, thereby simplifying the structure of the mobile work vehicle The weight can be reduced.

  At that time, if a step portion for placing the bridge axial direction end of each precast plate is formed on each upper precast rib, the precast plate can be laid efficiently. Thus, the construction efficiency of the upper floor slab can be further increased.

It is process drawing which shows the construction method of the box girder bridge concerning one Embodiment of this invention, Comprising: The figure which shows the box girder bridge used as the construction object along the II cross section of FIG. FIG. 1 (b) is taken out and shown in detail FIG. 3 is a view taken in the direction of the arrow III in FIG. 2 and taken along the line III-III in FIG. 4. IV-IV sectional view of FIG. (A) is a cross-sectional view taken along the line Va-Va in FIG. 2, and (b) is a cross-sectional view taken along the line Vb-Vb in FIG. Detailed view of main part of FIG. Detailed view of main part of FIG. Detailed view of relevant parts for explaining a part of the process of FIG. The figure similar to FIG. 3 which shows the construction method of the box girder bridge which concerns on the modification of the said embodiment. The figure similar to FIG. 6 which shows the construction method of the box girder bridge concerning the said modification

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a process diagram showing a box girder bridge construction method according to an embodiment of the present invention. FIG. 2 is a diagram illustrating FIG. 1B in detail. 3 is a view in the direction of arrow III in FIG. 2, and FIG. 4 is a cross-sectional view taken along line IV-IV in FIG.

  As shown in these drawings, a box girder bridge 10 to which the erection method according to the present embodiment is applied is an upper floor slab 12, a lower floor slab 14, and a pair of left and right webs 16 connecting them. So as to form a main girder structure extending in the direction of the bridge axis.

  1 shows the box girder bridge 10 along a cross section taken along line II in FIG. 4, and FIG. 3 shows the box girder bridge 10 along a cross section taken along line III-III in FIG. Yes.

  Each web 16 of the box girder bridge 10 has a configuration in which a plurality of panel members 22 are connected in the bridge axis direction. At that time, the panel members 22 are connected to each other at the upper end portions thereof via upper precast ribs 24 constituting a part of the upper floor slab 12.

  In the present embodiment, the box girder bridge 10 is constructed for each block having a predetermined length (for example, a length of about 6 m) by an overhang construction using the mobile work vehicle 100.

  That is, first, as shown in FIG. 1 (a), the installed existing block B (n) adjacent to the rear side of the upper floor slab 12 in which the lower floor slab 14 constitutes the unfinished top block B (n). -1) With the mobile work vehicle 100 moved from the upper floor slab 12 by one block, the mobile work vehicle 100 is used to move to the front side next to the top block B (n). By constructing each web 16 in the adjacent topmost block B (n + 1), and then placing the upper floor slab concrete 12C in the construction area Z1 indicated by the mesh line as shown in FIG. 1 (b) The upper floor slab 12 of the topmost block B (n + 1) is constructed and the lower floor slab concrete 14C is cast in the construction area Z2 indicated by the mesh line to construct the lower floor slab 14 of the top block B (n). Performed, then, as shown in FIG. 1 (c), by moving the mobile work vehicle 100 in top floor plate 12 of the top leading block B (n + 1), and performs the same operation as above.

  At that time, as shown in FIG. 1 (a), the construction of each web 16 in the topmost block B (n + 1) constitutes a part of the two panel members 22 and the upper floor slab 12 that constitute the web 16. The two upper precast ribs 24 are suspended and supported by the mobile work vehicle 100 and are alternately arranged in the bridge axis direction, and the PC steel material 26 is inserted in the bridge axis direction to be tensioned with these. It has become.

  In order to easily realize this, a part of the panel member 22 located on the front side of the two panel members 22 constituting each web 16 of the leading block B (n) constitutes the leading block B (n). It arrange | positions so that it may protrude ahead rather than the position of the front-end surface of the upper floor slab 12 to do.

  The mobile work vehicle 100 suspends and supports each panel member 22 with a pair of front and rear suspension members 112 and suspends and supports each upper precast rib 24 with a pair of left and right suspension members 114. In addition, the moving work vehicle 100 is moved to the upper floor slab 12 constituting the front block B (n), and the form receiving beam 102 for constructing the lower floor slab 14 of the front block B (n). Is suspended and supported, and a working scaffold 104 extending from the existing block B (n−1) to the topmost block B (n + 1) is suspended and supported on the lower side.

  Next, a specific configuration of the box girder bridge 10 to which the construction method according to the present embodiment is applied will be described.

  5A is a cross-sectional view taken along the line Va-Va in FIG. 2, and FIG. 5B is a cross-sectional view taken along the line Vb-Vb in FIG. FIG. 6 is a detailed view of relevant parts of FIG. 1A, and FIG. 7 is a detailed view of relevant parts of FIG.

  As shown in these drawings, two PC steel members 26 of each web 16 are arranged on both sides of the two panel members 22, and each of them inserts the two upper precast ribs 24 in the bridge axis direction. Is arranged.

  Each of these PC steel materials 26 is made of a PC steel rod, and is fixed to the upper precast rib 24 on the front side at the front end portion thereof. And when constructing each web 16 of the topmost block B (n + 1), the topmost part of each PC steel material 26 arranged on each web 16 constituting the constructed top block B (n) Each PC steel material 26 for block B (n + 1) is connected via a coupler 28. Prior to this connection, in each PC steel material 26 arranged in the completed top block B (n), its fixing is released and grout is injected into the surrounding gap.

  Each panel member 22 is a concrete plate-like member extending along a vertical plane including the bridge axis direction, and is formed in the same shape. Each of these panel members 22 has a horizontal plane at both upper and lower end surfaces, and both front and rear end surfaces have a shape in which a central portion in the vertical direction is constricted in a side view.

  FIG. 8 is a detail view of a main part for explaining a part of the process of FIG.

  As shown in the figure, each panel member 22 comes into contact with the front surface 24a and the rear surface 24b of each upper precast rib 24 at the rear end surface 22b and the front end surface 22a of the upper end portion thereof, It is performed on an uneven surface.

  Specifically, the front end surface 22a and the rear end surface 22b of each panel member 22 are formed with truncated pyramid-shaped convex portions 22a1 and 22b1, respectively. On the other hand, on the front surface 24a and the rear surface 24b of each upper precast rib 24, respectively. Are formed with truncated pyramid-shaped recesses 24a1 and 24b1, respectively. And the convex part 22b1 formed in the rear-end surface 22b of each panel member 22 fits into the recessed part 24a1 formed in the front surface 24a of each upper precast rib 24, and was formed in the front-end surface 22a of each panel member 22. A concave portion 24b1 formed on the rear surface 24b of each upper precast rib 24 is fitted into the convex portion 22a1. As a result, positioning between the two in the plane orthogonal to the bridge axis is achieved and a function as a shear key is achieved.

  The contact between each panel member 22 and each upper precast rib 24 is performed in a state where an acrylic resin adhesive or the like is applied to the contact surface.

  Further, when the panel members 22 and the upper precast ribs 24 are brought into contact with each other, the panel members 22 adjacent to each other in the bridge axis direction come into contact with each other on the front end surface 22c and the rear end surface 22d at the lower end portion. It is like that. These panel members 22 are also brought into contact with each other on the uneven surface.

  Specifically, a truncated pyramid-shaped recess 22c1 is formed on the front end surface 22c of each panel member 22, and a truncated pyramid-shaped convex portion 22d1 is formed on the rear end surface 22d of each panel member 22. And the convex part 22d1 formed in the rear-end surface 22d of the panel member 22 adjacent to the front side with respect to the recessed part 22c1 formed in the front-end surface 22c of each panel member 22 fits.

  The contact between the panel members 22 is also performed in a state where an acrylic resin adhesive or the like is applied to the contact surfaces.

  As shown in FIG. 7, the upper floor slab 12 in the topmost block B (n + 1) is constructed by laying a plurality of precast plates 32 between the upper precast ribs 24 adjacent in the bridge axis direction, and then the upper precast ribs 24. In addition, the precast plate 32 is used as an embedded formwork, and the upper floor slab concrete 12C is placed in the construction area Z1.

  In order to easily realize this, as shown in FIG. 8, step portions 24 a 2 and 24 b 2 for placing the end portions in the bridge axis direction of the respective precast plates 32 on the front surface 24 a and the rear surface 24 b of each upper precast rib 24. Is formed.

  As shown in FIGS. 4 and 5, the upper floor slab 12 is configured to have overhang portions on the left and right sides of a pair of left and right webs 16. In the upper floor slab 12, the embedded portion of the upper end of each web 16 is formed with a thick wall. And each PC steel material 42 extended in the direction of a bridge axis in the both sides of each web 16 is arranged at the lower end part of the embedding part. Each upper precast rib 24 is also formed with a thick portion at a position between the pair of left and right webs 16.

  On the other hand, in the lower floor slab 14, the embedded portion of the lower end portion of each web 16 is formed with a thick wall, and the portion positioned between the pair of left and right webs 16 is formed with a thin wall.

  A PC steel material 42 extending linearly in the direction orthogonal to the bridge axis is disposed in each upper precast rib 24 portion of the upper floor slab 12, and the portion of the upper floor slab concrete 12C is slightly uneven in the direction orthogonal to the bridge axis. A PC steel material 44 extending in the direction is arranged.

  Further, on the upper floor slab 12, a plurality of overhang steel members 34 for introducing prestress in the bridge axis direction to the upper floor slab concrete 12C at the time of overhang construction for each block are arranged as inner cables. The plurality of projecting steel members 34 are arranged at four positions so as to be located on both the left and right sides of each of the pair of left and right webs 16. Then, after the construction of the upper floor slab 12 of the topmost block B (n + 1) is completed, two sets of these extended steel materials 34 are tensioned and fixed by two sets on the front end surface.

  Next, the operation of this embodiment will be described.

  In the present embodiment, the lower floor slab 14 moves the mobile work vehicle 100 to the upper floor slab 12 constituting the unfinished top block B (n), and each web 16 in the topmost block B (n + 1) is moved. After the construction, the top floor block 12 of the topmost block B (n + 1) and the bottom floor slab 14 of the top block B (n) are constructed. At that time, the topmost block B (n + 1) In the construction of each web 16, two panel members 22 that constitute the web 16 and two upper precast ribs 24 that constitute a part of the upper floor slab 12 are suspended and supported by the mobile work vehicle 100 to form a bridge shaft. Since the PC steel material 26 is inserted in the direction of the bridge axis in a state where the steel plates 26 are alternately arranged in the direction of the bridge and is strained, the following operational effects can be obtained.

  That is, by using the two panel members 22 and the two upper precast ribs 24 to pre-construct each web 16 of the topmost block B (n + 1), the upper floor slab 12 of the topmost block B (n + 1). Can be easily performed. Further, the construction of the lower floor slab 14 of the top block B (n) can be easily performed by using the webs 16 that have been constructed. For this reason, the upper floor slab 12 of the top block B (n + 1) and the lower floor slab 14 of the top block B (n) are simultaneously constructed without moving the mobile work vehicle 100 to the top block B (n + 1). Can do.

  Therefore, according to this embodiment, in the method of laying the box girder bridge 10 by overhanging construction, rapid construction can be realized regardless of the structure of each web 16 constituting a part of the box girder.

  Moreover, in this embodiment, two PC steel materials 26 are arranged on both sides of the two panel members 22, and these PC steel materials 26 are inserted through the two upper precast ribs 24. The need to form an insertion hole for the PC steel material 26 in the panel member 22 can be eliminated, and the configuration can be simplified.

  Moreover, in this embodiment, since the shape of each panel member 22 is set so that each panel member 22 adjacent to a bridge axis direction may mutually contact | abut in the lower end part of this panel member 22, each panel member 22 is set. It is possible to efficiently transmit the compressive force in the bridge axis direction between each other.

  Further, in the present embodiment, each panel member 22 and each upper precast rib 24 come into contact with each other on the uneven surface, so that the positioning between the two in the plane orthogonal to the bridge axis and the function as a shear key are performed. Can be fulfilled.

  Moreover, in this embodiment, after constructing the upper floor slab 12 in the topmost block B (n + 1), after laying the precast plate 32 between the upper precast ribs 24 adjacent in the bridge axis direction, the upper precast rib 24 and the precast Since the upper floor slab concrete 12C is cast using the plate 32 as an embedded formwork, the assembly work of the formwork can be greatly simplified, thereby improving the construction efficiency of the upper floor slab 12. Can be increased.

  In addition, by doing so, when the upper floor slab 12 of the topmost block B (n + 1) is constructed, the load of the upper floor slab concrete 12C can be prevented from acting on the mobile work vehicle 100. The structure of 100 can be simplified and the weight can be reduced.

  At that time, each upper precast rib 24 is formed with step portions 24a2 and 24b2 for placing the bridge axial direction end portions of the respective precast plates 32, so that the precast plate 32 can be laid efficiently. Thus, the construction efficiency of the upper floor slab 12 can be further enhanced.

  In the above-described embodiment, the web 16 has been described as having a configuration in which the two panel members 22 and the two upper precast ribs 24 are alternately arranged in the bridge axis direction. The panel member 22 and the three or more upper precast ribs 24 are alternately arranged in the bridge axis direction, or the single panel member 22 and the single upper precast rib 24 are alternately arranged in the bridge axis direction. It is also possible to adopt the configuration described above. Even in the case of such a configuration, it is possible to obtain the same operational effects as in the case of the above embodiment.

  In the said embodiment, although each panel member 22 which comprises each web 16 demonstrated as what was comprised with the plate-shaped member made from concrete, it is comprised by the plate-shaped member made from steel, a corrugated steel plate, etc. Even in this case, the same effects as those of the above embodiment can be obtained.

  In the said embodiment, although the box girder bridge 10 used as application object demonstrated as what was provided with the left-right paired web 16, it became the structure by which the web is arrange | positioned at three or more places of a bridge axis orthogonal direction. Even in such a case, it is possible to obtain the same operational effects as in the case of the above embodiment.

  In the above embodiment, the lower floor slab 14 has been described as being formed over the entire region between the pair of left and right webs 16, but even when a partial region is formed as an opening. The same effects as those in the above embodiment can be obtained.

  Next, a modification of the above embodiment will be described.

  FIGS. 9 and 10 are views similar to FIGS. 3 and 6 showing a method for erection of a box girder bridge according to this modification.

  As shown in these drawings, the box girder bridge 210 to which the installation method according to the present modification is applied has a main girder structure substantially the same as the box girder bridge 10 of the above embodiment, but below that, The configurations of the floor slab 214 and each web 216 are partially different from those in the above embodiment.

  In other words, in this modification, when the webs 216 are constructed in the topmost block B (n + 1), the two panel members 222 that should form the webs 216 and a part of the lower floor slab 214 should be formed. In a state where the two lower precast ribs 224 are alternately arranged in the bridge axis direction, the PC steel material 226 is inserted through these in the bridge axis direction and is strained.

  At this time, each lower precast rib 224 is supported by a pair of left and right suspension members 314 that are suspended and supported by the upper precast rib 24 positioned immediately above the suspension member 314.

  Further, the PC steel material 226 is disposed so as to pass through the two lower precast ribs 224 in the bridge axis direction on the inner side in the bridge axis orthogonal direction with respect to each web 216. At that time, the PC steel material 226 for the topmost block B (n + 1) is connected to the PC steel material 226 for the top block B (n) that has been constructed through a coupler 228.

  Further, step portions 224 a 2 and 224 b 2 for placing the end portions in the bridge axis direction of the respective precast plates 232 are formed on the front and rear surfaces of the respective lower precast ribs 224. Then, in the construction of the lower floor slab 214 in the leading block B (n), after laying a plurality of precast plates 232 between the lower precast ribs 224 adjacent in the bridge axis direction, the lower precast ribs 224 and the precast plates 232 are attached. This is done by placing lower floor slab concrete 214C in the construction area Z2 as an embedded formwork.

  In the foremost block B (n + 1), after each PC steel material 226 is tensioned, a pair of turnbuckles 240 are diagonally crossed between lower precast ribs 224 adjacent in the bridge axis direction. Work to place is done.

  By employing the construction method according to this modification, the following operational effects can be obtained.

  That is, the stability of each panel member 222 during construction of each web 216 in the topmost block B (n + 1) is improved by tensioning the PC steel materials 26 and 226 at the upper and lower ends of each web 216. It is possible to effectively suppress the possibility of the lateral collapse or the like.

  In addition, after the construction of each web 216 in the topmost block B (n + 1), it is possible to easily perform the operation of adjusting the orientation of each panel member 222 using the turnbuckle 240 as in this modification. As a result, the orientation of each panel member 222 can be easily adjusted even when the bridge axis of the box girder bridge 210 extends in a curve in plan view.

  Furthermore, for the construction of the lower floor slab 214 in the top block B (n), a precast plate 232 is laid between the lower precast ribs 224 adjacent in the bridge axis direction, and the lower floor slab concrete 214 is used as an embedded formwork. Since it can be placed, the assembling work of the formwork can be greatly simplified, whereby the construction efficiency of the lower floor slab 214 can be increased.

  In the above modification, each lower precast rib 224 constituting each web 16 is described as being suspended and supported by the upper precast rib 24 positioned immediately above it in the topmost block B (n + 1). Instead of doing this, for example, a beam extending in the direction of the bridge axis or in the direction orthogonal to the bridge axis is disposed between the upper floor slab 12 and the lower floor slab 214 in a state of being suspended and supported by the mobile work vehicle 100. It is also possible to suspend and support each lower precast rib 224.

  In addition, the numerical value shown as a specification in the said embodiment and modification is only an example, and of course, you may set these to a different value suitably.

10, 210 Box girder bridge 12 Upper floor slab 12C Upper floor slab concrete 14, 214 Lower floor slab 16, 216 Web 22, 222 Panel member 22a Front end face 22a1, 22b1, 22d1 Convex part 22b Rear end face 24 Upper precast rib 24a Front face 24a1, 24b1 , 22c1 Recessed part 24a2, 24b2, 224a2, 224b2 Stepped part 24b Rear surface 26, 226 PC steel material 28, 228 Coupler 32, 232 Precast plate 34 Overhang steel material 42, 44 PC steel material 14C, 214C Lower floor slab concrete 100 Mobile work vehicle 102 type Frame support beam 104 Work scaffolding 112, 114, 314 Suspension material 224 Lower precast rib 240 Turnbuckle B (n-1) Existing block B (n) Leading block B (n + 1) Leading block Z1, Z2 Construction area

Claims (7)

Box girder bridges extending in the direction of the bridge axis by forming a box-shaped cross section with the upper floor slab, the lower floor slab, and a plurality of webs connecting them, for each block of a predetermined length by overhang construction using a mobile work vehicle In the method of erection,
After constructing each web in the topmost block next to the top block, with the mobile work vehicle moved to the top floor slab where the bottom floor slab constitutes the top block not yet constructed, Work on the upper floor slab and the lower floor slab of the top block,
At that time, the construction of each of the webs in the topmost block is carried out by using the mobile work vehicle with at least one panel member that should constitute the web and at least one upper precast rib that should constitute a part of the upper floor slab. A method for constructing a box girder bridge, characterized in that, in a state of being suspended and alternately arranged in the bridge axis direction, a PC steel material is inserted into the bridge axis direction and tension is applied thereto.   The PC steel material is arranged in two on both sides of the at least one panel member so that each of the PC steel materials is inserted into the at least one upper precast rib. How to build a box girder bridge.   The box according to claim 1 or 2, wherein the shape of each panel member is set so that the panel members adjacent in the bridge axis direction are in contact with each other at a lower end portion of the panel member. Girder bridge construction method.   When performing the construction of the webs in the topmost block, the at least one panel member that constitutes the web and at least one lower precast rib that constitutes a part of the lower floor slab are arranged in the bridge axis direction. The box girder bridge erection method according to claim 1 or 2, characterized in that the PC steel material is inserted in the bridge axis direction with respect to these in a state of being alternately arranged and is tensioned.   The method for constructing a box girder bridge according to any one of claims 1 to 4, wherein the panel members and the upper precast ribs are brought into contact with each other on an uneven surface.   For the construction of the upper floor slab in the topmost block, after laying a precast plate between the upper precast ribs adjacent to each other in the bridge axis direction, the upper floor slab concrete is placed using the upper precast rib and the precast plate as an embedded formwork. It is performed by doing, The construction method of the box girder bridge in any one of Claims 1-5 characterized by the above-mentioned.   7. A method for erection of box girder bridges according to claim 6, wherein a stepped portion for placing the end portion in the bridge axial direction of each precast plate is formed on each upper precast rib.

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