JP2008297777A - Method of constructing bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce construction period and construction cost in a method of constructing a bridge for constructing a multi-span continuous bridge by a span by span construction method. <P>SOLUTION: In the structure of a bridge 12 constructed between spans, a plurality of box beam core parts 14 are set in a multi-main box beam structure disposed at predetermined intervals in the directions perpendicular to the bridge axis. A plurality of core segments 24 forming the box beam core parts 14 for one bridge are disposed adjacent to each other in the bridge axis direction on an existing bridge positioned at the rear of the construction span S0. After the box beam core parts 14 are assembled by introducing the prestress in the bridge direction into these core segments, the box beam core parts 14 are moved to the construction span S0, and lifted to a construction girder 110 so installed as to straddle the construction span S0. The box beam core parts 14 lifted by the construction girder 110 are lowered onto a pair of pedestals 32 on both sides of the construction span S0 in the bridge axis direction, and, as required, moved to a predetermined position in the direction perpendicular to the bridge axis. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bridge construction method for constructing a multi-span continuous bridge by a so-called span-by-span construction method.

  Conventionally, the span-by-span construction method is known as one of the methods of constructing a multi-span continuous bridge.

  In this span-by-span construction method, for example, as described in “Patent Document 1”, a plurality of precast segments are arranged adjacent to each other in the bridge axis direction, and the precast segments in the bridge axis direction are arranged on the plurality of precast segments. By integrating by introducing stress, a bridge girder for one span is constructed, and a multi-span continuous bridge is constructed by sequentially repeating this for a plurality of spans.

  When such a span-by-span construction method is applied to a bridge girder having a multi-main girder box girder structure, the erection work has been conventionally performed according to a construction procedure as shown in FIG.

  That is, first, as shown in FIG. 2A, a plurality of box girder segments 2 are sequentially suspended from a girder for installation 100 so as to straddle between installation diameters, and these are connected to each other in the direction of the bridge axis. As shown in FIG. 4B, the box girder segments 2 for one main girder are all suspended and are in close contact with each other, as shown in FIG. As shown in the drawing, after placing concrete on joints 4 at both ends in the bridge axis direction, by introducing prestress in the bridge axis direction into the plurality of box girder segments 2 and integrating them, one main girder 6 After erection is completed, the erection girder 100 is moved in the direction orthogonal to the bridge axis as shown in FIG. 4D, and erection is performed in the same procedure for the other main girders.

JP-A-8-134845

  However, when constructing a bridge girder having a multi-main girder box girder structure by the conventional span-by-span construction method, if there is only one girder for erection, between each erection diameter, It is necessary to suspend a plurality of box girder segments, place joints and introduce prestress, and it is necessary to move the girder for construction in the direction perpendicular to the bridge axis every time construction of one main girder is completed. For this reason, there is a problem that the construction period becomes very long.

  On the other hand, in this case, if a plurality of construction girders are used, the construction period can be shortened to some extent, but the construction period cannot be significantly shortened and the construction cost becomes high. There is a problem.

  The present invention has been made in view of such circumstances, and in a bridge erection method in which a multi-span continuous bridge is erected by a span-by-span construction method, the construction period can be shortened and the construction cost can be reduced. The purpose is to provide a construction method.

  The present invention achieves the above object by setting the structure of the bridge girder to a predetermined multi-main girder box girder structure and dispersing the erection process between a plurality of diameters so that construction can be performed simultaneously. It is intended to plan.

That is, the bridge erection method according to the present invention is:
A plurality of precast segments are arranged so as to be adjacent to each other in the bridge axis direction, and a bridge girder for one span is constructed by introducing prestress in the bridge axis direction and integrating these precast segments. In the bridge erection method, a multi-span continuous bridge is erected by sequentially repeating for a plurality of spans.
The structure of the bridge girder constructed between each of the above diameters is set to a multi-main girder box girder structure in which a plurality of box girder core portions are arranged at predetermined intervals in the direction orthogonal to the bridge axis,
On the existing bridge girder located behind the span of installation span, a plurality of core segments composing one box girder core are arranged adjacent to each other in the bridge axis direction, and these core segments are arranged in the bridge axis direction. After assembling the box girder core by introducing the prestress of
This box girder core part is moved between the installation diameters and suspended in the installation girder installed so as to straddle the installation diameters.
The box girder core part suspended in the erection girder is suspended on a pair of bridge piers located on both sides in the bridge axis direction between the erection diameters,
Then, the suspended box girder core is moved to a predetermined position in the direction perpendicular to the bridge axis as necessary.

  The “box girder core portion” means a portion surrounding the box cross section in the box girder (that is, a portion not including the overhanging slab).

  Prestress introduced when assembling the box girder core part keeps the box girder core part in an assembled state from the suspension to the girder for construction to the movement in the direction perpendicular to the bridge axis. The specific size is not particularly limited as long as it can be prestressed.

  The specific movement method for moving the “box girder core” between the installation diameters is not particularly limited, and the “box girder core” is moved in the direction perpendicular to the bridge axis between the installation diameters. There are no particular restrictions on the specific movement method used for the movement.

  As shown in the above configuration, the bridge erection method according to the present invention is such that a multi-span continuous bridge is constructed by a span-by-span construction method, but a plurality of bridge girder structures constructed between each diameter are provided. The box girder core is set to a multi-main girder box girder structure with a predetermined interval in the direction orthogonal to the bridge axis, and one box is placed on the existing bridge girder located behind the span of span. After assembling the box girder core portion by arranging a plurality of core segments constituting the girder core portion so as to be adjacent to each other in the bridge axis direction and introducing prestress in the bridge axis direction to the plurality of core segments. The box girder core part is moved to the span between the installation spans, suspended in the girder for installation installed so as to straddle the span of the installation span, and the box girder core part suspended in the construction girder is inserted between the installation spans. Hang on a pair of bridge piers located on both sides of the bridge axis , Then, the box girder core portion was lowered this suspension, because is adapted to move to a predetermined position as necessary to bridge axis orthogonal direction, it is possible to obtain the following effects.

  That is, the assembling work of the box girder core part on the existing bridge girder located behind the span of the installation diameter, the installation work between the installation diameters of the box girder core part where this assembly was performed, and the rear side between the installation diameters It is possible to carry out the floor slab construction work in the span in parallel, which can significantly shorten the construction period compared to the conventional span-by-span construction method.

  Moreover, the girder for erection used in the invention of the present application is not limited to the whole of each box girder constituting the multi-main girder box girder structure as in the prior art. Like the span-by-span construction method (see Fig. 9), the box girder segment supplied from the existing bridge girder located behind the span of the span does not need to be turned sideways to pass between the struts of the girder for construction. Therefore, it is not necessary to rotate the box girder segment suspended in the erection girder by 90 °. For this reason, the construction of the girder for installation can be simplified and the workability can be further improved.

  In the present invention, since it is not necessary to move the girder for installation in the direction orthogonal to the bridge axis, the construction of the girder for installation can be simplified in this respect, and the construction cost can be reduced.

  As described above, according to the present invention, the construction period can be shortened and the construction cost can be reduced in the bridge construction method for constructing the multi-span continuous bridge by the span-by-span construction method.

  As described above, in the present invention, the construction of the floor slab in the bridge girder can be performed between the rear-side spans rather than the spanning spans. If the construction of the part to be performed is carried out by placing concrete on these precast plates in a state where a plurality of precast plates are bridged between the box girder core portions, the construction of the floor slab is efficient. Can be done. This makes it possible to easily adapt the floor slab construction work to the construction cycle of the assembly work of the box girder core part on the existing bridge girder and the installation work of the box girder core part between the spans.

  In the above configuration, as described above, the method of moving the box girder core portion between the installation diameters is not particularly limited. However, this movement is performed on a rail laid on the upper surface of the existing box girder core portion. If the box girder core part is placed on the carriage, the box girder core part can be moved efficiently and reliably.

  In the above configuration, the column head segment that forms the bridge axial direction end of the bridge girder is formed on the upper surface of each of the pair of bridge piers located on both sides in the bridge axial direction between the spans of the span. Each of a plurality of pairs of supporting columns that support the girder body of the erection girder is placed above a pair of cross beams adjacent to each other in each column head segment. If it is installed on the floor slab portion positioned, it is possible to stably support the erection girder without providing a new support structure. Also, by adopting such a configuration, the strut spacing in the direction perpendicular to the bridge axis in the girder for construction can be narrowed, so the strength of the girder for construction necessary for hanging the box girder core can be easily secured. Thus, the construction of the girder for installation can be further simplified.

  Even if the strut spacing of the girder for installation is reduced in this way, it is sufficient that the girder for construction can suspend only the box girder core part instead of the whole box girder, so that the hangering work is not hindered. Is possible.

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

  FIG. 1 is a process diagram showing an outline of a bridge erection method according to an embodiment of the present invention, and is a side view showing a multi-span continuous bridge 10 in the middle of erection as seen from the direction orthogonal to the bridge axis.

2 and 3 are views showing the multi-span continuous bridge 10 in the middle of the construction in a cross-section perpendicular to the bridge axis, and FIG. 2 (a) is IIa-IIa of FIG.
2B is a sectional view taken along line IIb-IIb in FIG. 1, FIG. 2C is a sectional view taken along line IIc-IIc in FIG. 1, and FIG. 3 is a sectional view taken along line III-III in FIG. FIG. FIG. 4 is a view in the direction of arrows IV in FIG.

  Further, FIGS. 5 to 8 are perspective views showing respective steps of FIGS. 1 (a) to (d).

  As shown in these drawings, in this embodiment, the multi-span continuous bridge 10 is constructed by a span-by-span method.

  Before describing the erection method of the present embodiment, the configuration of the multi-span continuous bridge 10 to be erected will be described.

  The multi-span continuous bridge 10 is a continuous bridge having a span length of about 40 m between the spans. As a structure of the bridge girder 12 constructed between the spans, a plurality of (specifically, four) boxes are used. A multi-main girder box girder structure in which the girder core portions 14 are arranged at predetermined intervals in the direction perpendicular to the bridge axis is employed.

  As shown in FIG. 2, in the bridge girder 12, a part of the floor slab is constituted by the four box girder core portions 14. That is, the intermediate floor slab 16 is formed flush with the box girder core portions 14 at the upper end portions between the box girder core portions 14, and the box girder core portions 14 positioned on both sides of the bridge axis orthogonal direction. An overhanging slab 18 is formed flush with each box girder core portion 14 at the upper end portion on the outer side in the direction perpendicular to the bridge axis. At that time, the intermediate floor slab 16 is constructed by placing concrete 22 on the precast plates 20 in a state where a plurality of precast plates 20 are bridged between a pair of box girder core portions 14 adjacent to each other. It is done by. On the other hand, the overhanging slab 18 is formed by placing concrete by cast-in-place.

  Further, as shown in FIGS. 3 and 4, a column head segment 32 constituting the bridge axial direction end portion of the bridge girder 12 is arranged via a support 50 on each pier 30 in the multi-span continuous bridge 10. Yes. The column head segment 32 includes a core segment 34 having a box-shaped cross-sectional shape formed at a position corresponding to each of the four box girder core portions 14, and a cross beam 36 formed between the core segments 34. The intermediate floor slab 38 formed flush with the core segments 34 at the upper ends of the cross beams 36 between the core segments 34 and the bridge shafts of the core segments 34 located on both sides of the bridge axis orthogonal direction. At the upper end portion on the outer side in the orthogonal direction, these core segments 34 and an extended floor slab 40 formed flush with each other are formed.

  In the following description, when it is necessary to distinguish the four box girder core parts 14, these box girder core parts 14 are respectively arranged in order from the left side in FIG. 2 as box girder core parts 14A, 14B, 14C, 14D. I will call it.

  In this embodiment, these four box girder core parts 14 are constructed in the order of box girder core parts 14A, 14B, 14D, and 14C. In addition, you may make it replace the construction order of box girder core part 14B and box girder core part 14D.

  First, the outline of the erection process is demonstrated about the box girder core part 14A erected first.

  As shown in FIGS. 1 (a) and 5, a plurality (specifically, twelve) of cores constituting one box girder core portion 14A on an existing bridge girder located behind the span S0. The segments 24 are arranged so as to be adjacent to each other in the bridge axis direction, are brought into close contact with each other via an adhesive, and then the prestress in the bridge axis direction is introduced into the plurality of core segments 24 to thereby form the box girder core portion 14A. assemble. The prestress is introduced by arranging an inner cable (not shown) extending in the bridge axis direction with respect to the plurality of core segments 24 and tensioning the inner cable.

  Then, the box girder core portion 14A is moved to the span between spans S0 and is hung on the span girder 110 installed so as to straddle the span between spans S0. Thereafter, the box girder core portion 14A suspended in the erection girder 110 is suspended on a pair of bridge piers 30 located on both sides of the span span S0 in the bridge axis direction, and the suspended girder core portion is suspended. 14A is moved to a predetermined position (that is, the first position from the left in FIG. 3) in the direction orthogonal to the bridge axis.

  In parallel with the movement and erection of the box girder core part 14A, a plurality of core segments 24 are arranged on the existing bridge girder located behind the erection span S0, and the box girder installed second. The core part 14B is assembled.

  As shown in FIG. 1B and FIG. 6, the second girder core portion 14B to be erected is assembled, moved and erected in the same manner as the box girder core portion 14A.

  Similarly, the third, fourth box girder core portions 14D, 14C are assembled, moved, and installed in the same manner as the box girder core portion 14A.

  In the above-described erection process, the box girder core portion 14 is moved to the pair of front and rear carriages 114 that run on the rail 112 laid on the rear side of the erection span S0. Is carried out with the At this time, the rail 112 is connected to the front end of the upper surface of the box girder core portion 14C installed in the rear span S-1 adjacent to the rear side of the span span S0 from the position of the box girder core portion 14C on the existing bridge girder. Lay it up to the position.

  In the erection process, the box girder core 14 is assembled on the existing bridge girder positioned on the rear side of the erection span S0 on the pedestal 116 fixedly installed on the existing bridge girder so as to cover the rail 112.

  In the above erection process, the box girder core portion 14 suspended on the pair of bridge piers 30 located on both sides of the bridge span S0 in the bridge axis direction can be smoothly moved in the bridge axis orthogonal direction. As shown in FIGS. 3 and 4, a temporary support base 118 extending in a direction orthogonal to the bridge axis is installed at the end of the bridge span S0 side at the upper end surface of each pier 30, and the temporary support base 118 is attached to the temporary support base 118. The box girder core unit 14 is suspended, and the box girder core unit 14 is moved to a predetermined position by sliding the upper surface of the temporary support base 118. At that time, the temporary support base 118 is adjusted so as to be substantially the same height as the support 50 of the bridge girder 12 installed on the upper end surface of the pier 30. As shown in FIGS. 5 and 6, a scaffold 130 for performing the hanging and lateral movement work of the box girder core portion 14 is installed in the vicinity of each pier 30 in the span span S <b> 0.

  In addition to the box girder core portion 14A, for the two box girder core portions 14B and 14D that require movement in the direction perpendicular to the bridge axis, the upper surface of the temporary support base 118 is slid to a predetermined position (that is, in FIG. 3). 2nd and 4th positions from the left), but the box girder core portion 14C is suspended from the temporary support base 118.

  When the installation of the four box girder core portions 14 is completed by the above installation process, as shown in FIG. 1 (c) and FIG. 7, the installation girder 110 has a front side diameter adjacent to the front side of the installation span S0. The four box girder cores 14 are installed in the same manner with the front side gap S + 1 as a new installation gap.

  On the other hand, in the construction span S0 after the construction girder 110 has moved to the front span S + 1, after placing concrete on the joints 42 at both ends in the bridge axis direction of each box girder core portion 14, each of these boxes Installation of each box girder core portion 14 is completed by introducing prestress in the bridge axis direction and integrating the plurality of core segments 24 constituting the girder core portion 14. This pre-stress is introduced by tensioning the outer cable 44 extending along the bridge axis direction disposed along each box girder core portion 14.

  At this time, in the rear side span S-1, as a part of the construction of the intermediate floor slab 16, a plurality of precast plates 20 are bridged between a pair of box girder core portions 14 adjacent to each other.

  Thereafter, as shown in FIGS. 1 (d) and 8, spanning between the pair of box girder core portions 14 adjacent to each other as the remainder of the construction of the intermediate floor slab 16 in the rear side span S-1. Concrete 22 is placed on the plurality of precast plates 20 formed, and the floor slab 18 is constructed by cast-in-place on the outside of each box girder core portion 14 located on both sides in the direction orthogonal to the bridge axis. Do.

  As shown in FIG. 3, the girder 110 for erection used in the erection process includes a pair of girder main bodies 120 extending in the bridge axis direction, and struts that support the pair of girder main bodies 120 at two locations in the bridge axis direction. 122, a tip post 124 attached to the tip of the pair of girder main bodies 120, a movable beam 126 laid over the pair of girder main bodies 120 at two locations in the bridge axis direction, and each of these movable beams A lifting tool 128 having an upper end supported by 126 is formed.

  And in this embodiment, when installing this installation girder 110 so that straddle span S0 may be straddled, each of the pair of pillars 122 before and after that is located on each side of the bridge span in the span span S0. In the part segment 32, it installs in the intermediate | middle floor slab 38 located above a pair of cross girder 36 adjacent to the core segment 34 formed in the position corresponding to the box girder core part 14C.

  As described in detail above, the bridge erection method according to the present embodiment is such that the multi-span continuous bridge 10 is erected by the span-by-span method, but the structure of the bridge girder 12 erected between the respective diameters. Is set on a multi-main girder box girder structure in which a plurality of box girder core portions 14 are arranged at a predetermined interval in the direction perpendicular to the bridge axis, and on the existing bridge girder located behind the span span S0, A plurality of core segments 24 constituting one box girder core portion 14 are arranged so as to be adjacent to each other in the bridge axis direction, and prestress in the bridge axis direction is introduced into the plurality of core segments 24 to thereby form a box girder. After assembling the core part 14, the box girder core part 14 is moved to the spanning span S <b> 0 and suspended on the spanning girder 110 that is installed across the spanning span S <b> 0. Suspended box girder core 1 Are suspended on a pair of bridge piers located on both sides in the bridge axis direction of the span span S0, and then the suspended box girder core portion 14 is moved to a predetermined position in the direction perpendicular to the bridge axis as necessary. Therefore, the following effects can be obtained.

  That is, the assembling work of the box girder core portion 14 on the existing bridge girder located behind the span of span S0, the installation work of the box girder core portion 14 having been assembled in the span of span S0, and this span of span It is possible to perform the floor slab construction work in the rear side span S-1 adjacent to the rear side of S0 in parallel, thereby significantly shortening the construction period compared to the conventional span-by-span construction method. Can do.

  Moreover, the erection girder 110 used in the present embodiment only needs to be able to suspend only the box girder core portion 14 instead of the entire box girder constituting the multi-main girder box girder structure as in the prior art. As in the conventional span-by-span construction method (see Fig. 9), the box girder segment supplied from the existing bridge girder located behind the span of the span must be placed sideways to pass between the struts of the girder for construction. Therefore, it is not necessary to rotate the box girder segment suspended in the erection girder by 90 °. For this reason, the construction of the girder for installation can be simplified and the workability can be further improved.

  Moreover, in this embodiment, since it is not necessary to move the construction girder 110 in the direction orthogonal to the bridge axis, the construction of the construction girder 110 can be simplified in this respect as well, thereby reducing the construction cost. Can do.

  As described above, according to the present embodiment, the construction period can be shortened and the construction cost can be reduced in the bridge construction method for constructing the multi-span continuous bridge 10 by the span-by-span construction method.

  In the present embodiment, the construction of the intermediate floor slab 16 and the overhanging floor slab 18 in the bridge girder 12 is performed at the rear side span S-1, but at this time, the position between the box girder core portions 14 is determined. The intermediate floor slab 16 is constructed by placing concrete 22 on the precast plates 20 in a state where a plurality of precast plates 20 are bridged between the box girder core portions 14. Therefore, the construction of the intermediate floor slab 16 and the overhanging floor slab 18 can be performed efficiently. And it becomes possible easily to adapt this floor slab construction work to the construction cycle of the assembly work of the box girder core part 14 on the existing bridge girder and the installation work of the box girder core part 14 in the span span S0. .

  Further, in this embodiment, the movement of the box girder core portion 14 to the span span S0 is transferred to the carriage 114 running on the rail 112 laid on the upper surface of the existing box girder core portion 14C. Since the box girder core portion 14 can be moved efficiently and reliably.

  Furthermore, in the present embodiment, the column head segment 32 constituting the bridge axial direction end portion of the bridge girder 12 is provided on the upper surface of each of the pair of bridge piers 30 positioned on both sides in the bridge axial direction of the span span S0. 34, each of the plurality of pairs of columns 122 supporting the girder 110 for installation is placed on both sides of the spanning span S0 in the bridge axis direction. In each column head segment 32 positioned, it is installed on an intermediate floor slab 38 positioned above a pair of cross beams 36 adjacent to a core segment 34 formed at a position corresponding to the box beam core portion 14C. Therefore, it is possible to stably support the erection girder 110 without providing a new support structure. Further, by adopting such a configuration, it is possible to reduce the interval between the columns in the bridge girder orthogonal direction in the erection girder 110, so that the strength of the erection girder 110 necessary for hanging the box girder core portion 14 is increased. This can be ensured easily, whereby the construction of the erection girder 110 can be further simplified.

  Even if the strut spacing of the erection girder 110 is reduced in this way, it is sufficient that the erection girder 110 can suspend only the box girder core portion 14 instead of the entire box girder. This can be done without any problem.

  In the said embodiment, although the multi-span continuous bridge 10 used as construction object was demonstrated as what was equipped with the four box girder core parts 14 as the bridge girder 12 constructed between each diameter. The same construction as in the above embodiment also in the case of a configuration with two or three box girder core portions 14 or in the case of a configuration with five or more box girder core portions 14 By adopting the method, it is possible to obtain the same effects as those of the above embodiment. However, in the case where there are two box girder core portions 14, the structure is not formed in which the cross beams 36 are formed on both sides of each core segment 34 in the column head segment 32, so that the support column 122 of the erection girder 110 is installed. It is necessary to newly provide this structure on the pier 30.

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

BRIEF DESCRIPTION OF THE DRAWINGS It is process drawing which shows the outline | summary of the construction method of the bridge which concerns on one Embodiment of this invention, Comprising: The side view which sees the multi span continuous bridge in the middle of construction seen from a bridge axis orthogonal direction FIG. 2 is a diagram showing a multi-span continuous bridge in the middle of the construction in a cross section perpendicular to the bridge axis, in which FIG. (A) is a sectional view taken along line IIa-IIa in FIG. 1, and FIG. Sectional view, (c) is a sectional view taken along line IIc-IIc in FIG. Sectional view taken along the line III-III in Fig. 1, showing the multi-span continuous bridge in the middle of the construction in a cross section perpendicular to the bridge axis IV direction arrow view of FIG. The perspective view which shows the process of Fig.1 (a) The perspective view which shows the process of FIG.1 (b). The perspective view which shows the process of FIG.1 (c). A perspective view showing the process of FIG. Figure similar to Figure 1 showing a conventional example

Explanation of symbols

10 Multi-span continuous bridge 12 Bridge girder 14, 14A, 14B, 14C, 14D Box girder core part 16, 38 Intermediate floor slab 18, 40 Overhang slab 20 Precast plate 22 Concrete 24, 34 Core segment 30 Bridge pier 32 Column head segment 36 Cross girder 42 Joint 44 Outer cable 50 Bearing 110 Girder for installation 112 Rail 114 Dolly 116 Drawer 116 Pedestal 118 Temporary receiving stand 120 Girder main body 122 Support column 124 Tip column 126 Movable beam 128 Lifting tool 130 Scaffolding S0 Installation span S + 1 Front side span S- 1 Between rear side

Claims (4)

A plurality of precast segments are arranged so as to be adjacent to each other in the bridge axis direction, and a prestress in the bridge axis direction is introduced into and integrated with the plurality of precast segments to construct a bridge girder for one span. In the bridge erection method, a multi-span continuous bridge is erected by sequentially repeating for a plurality of spans.
The structure of the bridge girder constructed between the above-mentioned diameters is set to a multi-main girder box girder structure in which a plurality of box girder core parts are arranged at predetermined intervals in the direction orthogonal to the bridge axis,
On the existing bridge girder located behind the span of installation span, a plurality of core segments constituting one box girder core portion are arranged adjacent to each other in the bridge axis direction, and these core segments are arranged in the bridge axis direction. After assembling the box girder core by introducing the prestress of
This box girder core part is moved between the installation diameters and suspended in the installation girder installed so as to straddle the installation diameters.
The box girder core part suspended in the erection girder is suspended on a pair of bridge piers located on both sides in the bridge axis direction between the erection diameters,
Then, the suspended bridge girder core is moved to a predetermined position in the direction perpendicular to the bridge axis as necessary, and a bridge erection method is provided. Construction of the floor slab in the bridge girder is performed between the rear spans rather than the span between the spans,
At that time, the construction of the part located between the box girder core parts of the floor slab is placed on the precast board with a plurality of precast boards laid between the box girder core parts. The bridge erection method according to claim 1, wherein the bridge erection method is performed.   The movement of the box girder core part between the installation diameters is performed in a state where the box girder core part is placed on a carriage that runs on a rail laid on the upper surface of the existing box girder core part. The method for laying a bridge according to claim 1 or 2, characterized in that: A column head segment constituting a bridge axis direction end portion of the bridge girder is disposed on the upper surface of each of the pair of bridge piers positioned on both sides in the bridge axis direction between the installation spans. Are pre-constructed so that
The plurality of pairs of columns supporting the girder main body of the erection girder are installed on a floor slab portion located above a pair of cross beams adjacent to each other in each column head segment. Item 4. A method for laying a bridge according to any one of items 1 to 3.

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