JP4040639B2 - Corrugated steel web bridge - Google Patents

Description

  The present invention relates to a corrugated steel web bridge in which an upper floor slab, a lower floor slab, and a pair of left and right corrugated steel webs connecting them form a box girder extending in the bridge axis direction.

  Corrugated steel web bridges have been increasingly used in recent years because they can reduce the weight of the main girder and can rationalize construction and save labor.

  This corrugated steel web bridge has a structure in which a box girder extending in the bridge axis direction is formed by an upper floor slab, a lower floor slab and a pair of left and right corrugated steel webs connecting them. Patent Document 1 ”describes a corrugated steel web bridge in which a plurality of precast ribs are used as components of an upper floor slab.

  That is, the corrugated steel web bridge upper floor slab described in “Patent Document 1” has a plurality of precast ribs extending in a direction perpendicular to the bridge axis arranged at predetermined intervals in the bridge axis direction, and each of these precast ribs is mutually connected. It is formed by placing concrete on these precast plates in a state where a plurality of precast plates are bridged between them.

JP 2004-1106060 A

  In such a corrugated steel web bridge, when the width of the upper floor slab is increased, the lateral width of the box girder is also increased accordingly. In such a case, as described in the above-mentioned “Patent Document 1”, if the corrugated steel sheet web is additionally arranged in the center part in the direction perpendicular to the bridge axis of the box girder, the required strength can be obtained. It can be secured.

  However, when the corrugated steel web is additionally arranged in this manner, the weight of the main girder increases correspondingly, and the advantage of the corrugated steel web bridge that the main girder weight can be reduced is diminished. There is a problem.

  The present invention has been made in view of such circumstances, and even when the width of the upper floor slab is increased, the required strength is ensured while minimizing the increase in the weight of the main girder. An object of the present invention is to provide a corrugated steel web bridge that can be used.

  The present invention is intended to achieve the above object by providing a plurality of struts in a predetermined arrangement in the internal space of the box girder.

That is, the corrugated steel web bridge according to the present invention is
In the corrugated steel web bridge in which a box girder extending in the direction of the bridge axis is formed by an upper floor slab and a lower floor slab and a pair of left and right corrugated steel webs connecting them,
In the state in which the upper floor slab is arranged with a plurality of precast ribs extending in a direction perpendicular to the bridge axis at predetermined intervals in the bridge axis direction, and a plurality of precast plates are bridged between the precast ribs. It is formed by placing concrete on the
A plurality of struts having an upper end connected to the precast rib and a lower end connected to the lower floor slab are provided in the cross section of the bridge axis including the precast ribs in the internal space of the box girder. And
As the plurality of struts, an upper end portion is connected to the precast rib at a central portion in a bridge axis orthogonal direction in the box girder portion, and a lower end portion is connected to a portion near the connection portion with the corrugated steel web in the lower floor slab. A pair of struts and an upper end connected to the precast rib at a central portion of the box girder in the direction perpendicular to the bridge axis, and a lower end of the lower girder at the central portion of the box girder in the direction perpendicular to the bridge axis. A strut connected to the plate,
Each of the precast ribs is divided into two at the central portion of the box girder in the direction orthogonal to the bridge axis, and the pair of precast ribs divided into two are arranged at a predetermined interval from each other,
A cast-in-place concrete block is placed in the space between the pair of precast ribs, and upper ends of the plurality of struts are connected to the cast-in-place concrete block. .

Each of the above “struts” has a material, a cross-sectional shape, etc., as long as the upper end portion is connected to the precast rib and the lower end portion is connected to the lower floor slab in the cross section perpendicular to the bridge axis including each precast rib. The specific configuration is not particularly limited .

  In addition, the concrete construction method at the time of constructing the corrugated steel web bridge concerning this invention is not specifically limited, For example, the overhang construction method, the extrusion construction method, etc. are employable.

  As shown in the above configuration, in the corrugated steel web bridge according to the present invention, a box girder portion extending in the bridge axis direction is formed by the upper floor slab, the lower floor slab, and the pair of left and right corrugated steel webs connecting them. The upper floor slab has a plurality of precast ribs extending in a direction perpendicular to the bridge axis at predetermined intervals in the bridge axis direction, and a plurality of precast plates are bridged between the precast ribs. In this state, it is formed by placing concrete on these precast plates, so it is possible to construct the upper floor slab without using a complicated formwork. Improvements can be made.

  In addition, in the corrugated steel web bridge according to the present invention, the upper end portion is connected to the precast rib and the lower end portion is the lower floor in the bridge axis orthogonal cross section including each precast rib in the internal space of the box girder portion. Since a plurality of struts connected to the plate are provided, the required strength can be ensured even if the lateral width of the box girder is increased to some extent. As a result, the weight of the main girder can be greatly reduced as compared with the case where the corrugated steel sheet web is additionally arranged in the center part in the direction perpendicular to the bridge axis of the box girder as in the prior art.

  As described above, according to the present invention, in the corrugated steel web bridge, even when the width of the upper floor slab is increased, the required strength can be ensured while minimizing the increase in the weight of the main girder.

Moreover, in the present invention, as the plurality of struts arranged in the bridge axis orthogonal cross section including each precast rib, the upper end portion is connected to the precast rib at the center portion in the bridge axis orthogonal direction in the box girder portion, and the lower end portion is Since it has a configuration with a pair of struts connected to the vicinity of the connecting part with the corrugated steel web in the lower floor slab, the truss structure can be formed in the bridge axis orthogonal section including each precast rib Thus, the required strength can be easily ensured.

At that time, as the plurality of struts, the upper end portion is further connected to the precast rib at the central portion of the box girder portion in the direction perpendicular to the bridge axis, and the lower end plate is the lower floor slab at the middle portion of the box girder portion in the direction perpendicular to the bridge axis. since it has a configuration in which a connecting struts in, it is possible to further improve the strength.

And by adopting such a configuration, each precast rib is divided into two at the center portion of the box girder in the direction perpendicular to the bridge axis, but the bridge axis orthogonal cross section including the precast rib is included. The precast ribs divided into two can be supported at the divided portions by the upper ends of the plurality of struts arranged inside.

  In the above configuration, if the rib-shaped protrusions extending in the direction orthogonal to the bridge axis are formed in the bridge axis orthogonal cross section including each precast rib on the upper surface of the lower floor slab, sufficient support strength for each strut is secured. can do.

  Further, in the above configuration, if the plurality of notches for installing the plurality of precast ribs are formed at the upper end of each corrugated steel web, the following operational effects can be obtained.

  That is, each precast rib is inserted and installed in the notch portion with respect to the pair of left and right corrugated steel webs, and the precast plate is bridged and the concrete is placed with the precast ribs positioned. be able to. This also allows each corrugated steel web to be embedded and joined to the upper floor slab, eliminating the need to weld and fix a steel flange to the upper end of each corrugated steel web as in the prior art. Thus, the weight of each corrugated steel web can be reduced.

  In that case, if it is set as the structure by which the plate for mounting a precast rib was attached to the bottom part of each notch part, installation of each precast rib can be performed correctly and stably.

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

  FIG. 1 is a cross-sectional view orthogonal to a bridge axis showing a corrugated steel web bridge 10 according to an embodiment of the present invention. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III of FIG. Further, FIG. 4 is an exploded view showing a plurality of types of precast members constituting the corrugated steel web bridge 10.

  As shown in these drawings, the corrugated steel web bridge 10 has a box girder 20 extending in the bridge axis direction by an upper floor slab 12, a lower floor slab 14, and a pair of left and right corrugated steel webs 16 connecting them. Thus, the upper floor slab 12 is formed so as to protrude from the box girder portion 20 to both sides in the direction perpendicular to the bridge axis. The box girder portion 20 has a horizontally long inverted trapezoidal cross-sectional shape, and its left and right width is set to a value of about 10 m at the upper end portion.

  The upper floor slab 12 is bridged between a plurality of precast ribs 22 extending in a direction orthogonal to the bridge axis and arranged at a predetermined interval (for example, an equal interval of about 2.4 m) in the bridge axis direction. A plurality of precast plates 24 and cast-in-place concrete 26 placed on the precast plates 24 are configured.

  At this time, each precast rib 22 is formed so as to extend over the entire width of the upper floor slab 12, and a rib-like protrusion 22 a serving as a stopper when the precast plate 24 is placed is formed on the upper surface thereof.

  Further, the cast-in-place concrete 26 is formed as a downward projecting portion 26a projecting downward at the both ends of the box girder portion 20 in the direction orthogonal to the bridge axis, and extends in the direction of the bridge axis. A fixing block 26b for fixing the outer cable 52 is formed. Each precast rib 22 has an insertion hole (not shown) through which the outer cable 52 is inserted.

  The lower floor slab 14 includes a main body portion 32 made of cast-in-place concrete and concrete flange portions 34 positioned on both sides of the main body portion 32, and includes a bridge including each precast rib 22 on the upper surface of the main body portion 32. A plurality of rib-shaped protrusions 32a extending in the direction orthogonal to the bridge axis are formed in the axis orthogonal cross section.

  Each corrugated steel web 16 is disposed so as to incline outward in the direction perpendicular to the bridge axis with respect to a vertical plane extending in the bridge axis direction, and a lower end portion thereof is embedded and joined to each concrete flange portion 34. On the other hand, the upper end portions of the corrugated steel webs 16 are embedded and joined to the downward projecting portions 26 a of the cast-in-place concrete 26.

  Three struts 40A having an upper end connected to the precast rib 22 and a lower end connected to the lower floor slab 14 in the bridge axis orthogonal cross section including each precast rib 22 in the internal space of the box girder 20; 40B is provided. Each of these struts 40A and 40B is configured as a precast member having a rectangular cross section.

  Among these three struts 40A and 40B, two struts 40A have upper ends connected to the precast ribs 22 in the center portion of the box girder 20 in the direction perpendicular to the bridge axis, and lower ends of the lower struts. 14, the remaining one strut 40 </ b> B is connected to the precast rib 22 at the central portion of the box girder 20 in the direction perpendicular to the bridge axis. The lower end of the box girder 20 is connected to the lower floor slab 14 at the center in the direction perpendicular to the bridge axis.

  At that time, the upper end portion of each strut 40A is connected to the precast rib 22 via a cast-in-place concrete block 42 placed on the lower surface of the precast rib 22, and the lower end portion is a main body portion of the lower floor slab 14 32 is connected to the lower floor slab 14 via a cast-in-place concrete block 44A placed on the upper surface of the rib-like protrusion 32a. The upper end of the strut 40B is connected to the precast rib 22 via a cast-in-place concrete block 42, and the lower end of the strut 40B is placed on the upper surface of the rib-like protrusion 32a in the main body 32 of the lower floor slab 14. It is connected to the lower floor slab 14 via the cast-in-place concrete block 44B.

  FIG. 5 is a main part perspective view showing the installation structure of the precast rib 22 at the upper end of the corrugated steel web 16.

  As shown in the figure, a plurality of notches 16a for installing a plurality of precast ribs 22 are formed at the upper end of each corrugated steel web 16 at predetermined intervals in the bridge axis direction. Each of these notches 16a is formed in a U shape along the cross-sectional shape of the precast rib 22, and a plate 36 for mounting the precast rib 22 is attached to the bottom of the notch 16a by welding or the like. ing. As a result, the precast rib 22 is placed on the plate 36 in a state where the precast rib 22 is inserted so as to be fitted into the notch 16 a of each corrugated steel web 16.

  As described above in detail, the corrugated steel web bridge 10 according to the present embodiment is a box girder extending in the bridge axis direction by the upper floor slab 12, the lower floor slab 14, and the pair of left and right corrugated steel webs 16 connecting them. The upper floor slab 12 has a plurality of precast ribs 22 extending in a direction orthogonal to the bridge axis at predetermined intervals in the bridge axis direction, and the precast ribs 22 are mutually connected. Since it is formed by placing cast-in-place concrete 26 on these precast plates 24 with a plurality of precast plates 24 sandwiched between them, construction of the upper floor slab 12 without using a complicated formwork As a result, it is possible to improve the erection workability.

  In addition, the corrugated steel web bridge 10 according to the present embodiment has an upper end connected to the precast rib 22 and a lower end in the bridge axis orthogonal cross section including each precast rib 22 in the internal space of the box girder 20. Since the three struts 40A and 40B having portions connected to the lower floor slab 14 are provided, the required strength can be ensured even if the lateral width of the box girder 20 is increased to some extent. As a result, the weight of the main girder can be greatly reduced as compared with the case where the corrugated steel sheet web is additionally arranged in the center part in the direction perpendicular to the bridge axis of the box girder as in the prior art.

  Thus, according to the present embodiment, in the corrugated steel web bridge 10, even when the width of the upper floor slab 12 is increased, the required strength is ensured while minimizing the increase in the weight of the main girder. Can do.

  In particular, in the present embodiment, two struts 40A out of the three struts 40A and 40B are connected to the precast rib 22 at the upper end portion of the box girder portion 20 in the center portion in the direction perpendicular to the bridge axis, and the lower end portion is Since the lower floor slab 14 is connected to the vicinity of the connecting portion with the corrugated steel web 16, a truss structure can be formed in the cross section perpendicular to the bridge axis including each precast rib 40 </ b> A. Can be secured.

  At that time, in this embodiment, the remaining one strut 40B out of the three struts 40A and 40B is connected to the precast rib 22 at the upper end portion of the box girder portion 20 in the center portion in the direction perpendicular to the bridge axis, Since the lower end portion is connected to the lower floor slab 14 in the central portion of the box girder portion 20 in the direction orthogonal to the bridge axis, the strength can be further improved.

  Furthermore, in the present embodiment, the rib-like protrusions 32a extending in the direction orthogonal to the bridge axis are formed in the bridge axis orthogonal cross section including the respective precast ribs 22 on the upper surface of the main body 32 of the lower floor slab 14. Sufficient support strength for the struts 40A and 40B can be secured.

  Moreover, in this embodiment, since the several notch part 16a for installing the several precast rib 22 is formed in the upper end part of each corrugated steel plate web 16, each precast rib 22 is made into a pair of corrugated left and right. By inserting and installing in the notch part 16a with respect to the steel plate web 16, the precast board 24 can be bridge | crossed and concrete placement can be performed in the state which these each precast rib 22 positioned. Moreover, since each corrugated steel web 16 can be embedded and bonded to the upper floor slab 12 by this, it is possible to eliminate the need to weld and fix a steel flange to the upper end of each corrugated steel web as in the prior art. Thus, each corrugated steel web 16 can be reduced in weight.

  In addition, in the present embodiment, the plate 36 for placing the precast ribs 22 is attached to the bottom of each notch 16a, so that the precast ribs 22 can be installed accurately and stably. Can do.

  In the present embodiment, since the concrete flange portion 34 constituting a part of the lower floor slab 14 is embedded and joined to the lower end portion of each corrugated steel web 16, the concrete is applied to the lower end portion of each corrugated steel web 16. This eliminates the need for installation and eliminates the need for the formwork, thereby simplifying the connecting operation between the corrugated steel web 16 and the lower floor slab 14.

  By the way, in the corrugated steel web bridge 10 according to the above embodiment, the box girder portion 20 has been described as having a horizontally long inverted trapezoidal cross-sectional shape, but other cross-sectional shapes such as a horizontally long rectangular shape, for example. Even in the case of having the above, by adopting the configuration of the above-described embodiment, it is possible to obtain the same effects as the above-described embodiment.

  Moreover, in the said embodiment, although the three struts 40A and 40B were demonstrated as what is a precast strut made from concrete, these can also be comprised with steel materials.

  In addition, the value which shows the item of the corrugated steel web bridge 10 concerning the said embodiment is an illustration to the last, and of course may be set to the value other than this.

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

  FIG. 6 is a cross-sectional view orthogonal to the bridge axis showing the corrugated steel web bridge 110 according to this modification.

  As shown in the figure, the corrugated steel web bridge 110 has a basic configuration similar to that of the corrugated steel web bridge 10 according to the above embodiment, but the lateral width of the box girder 120 is the same as that of the above embodiment. This is different from the above embodiment in that it is set to a value larger than the box girder 20 (for example, a value of about 12 m at the upper end). Moreover, in the said embodiment, each precast rib 22 is comprised with the single member over the full length, but in this modification, each precast rib 122 is the bridge-axis orthogonal center of the box beam part 120. This is also different from the above embodiment in that the configuration is divided into two parts.

  The pair of precast ribs 122A and 122B constituting each of these precast ribs 122 are arranged with their end surfaces near the bridge axis spaced apart from each other, and the space between the two precast ribs 122A and 122B includes: A cast-in-place concrete block 142 is placed. And the upper end part of three struts 40A and 40B is connected with this cast-in-place concrete block 142. As shown in FIG.

  In this modification, each precast rib 122 is divided into two precast ribs 122A and 122B in the central portion of the box girder portion 120 in the direction perpendicular to the bridge axis, so that it can be easily transported, etc. Therefore, the erection workability can be improved.

  In this modification, a cast-in-place concrete block 142 is placed in a space between the two precast ribs 122A and 122B constituting each precast rib 122, and three struts 40A are placed in the cast-in-place concrete block 142. , 40B is connected to each other, so that each precast rib 122 can be supported even though it is divided into two. As a result, even when the width of the upper floor slab 12 is increased, this can be sufficiently accommodated.

Bridge axis orthogonal sectional view showing a corrugated steel web bridge according to an embodiment of the present invention Partial enlarged view of FIG. Sectional view along line III-III in Fig. 2 The figure which decomposes | disassembles and shows the multiple types of precast member which comprises the said corrugated steel web bridge The principal part perspective view which shows the installation structure of the precast rib in the upper end part of the corrugated steel web of the said corrugated steel web bridge Bridge axis orthogonal sectional view showing a corrugated steel web bridge according to a modification of the embodiment.

Explanation of symbols

10, 110 Corrugated steel web bridge 12 Upper floor slab 14 Lower floor slab 16 Corrugated steel web 16a Notch 20, 120 Box girder 22, 122, 122A, 122B Precast rib 22a Rib-shaped protrusion 24 Precast plate 26 Cast-in-place concrete 26a Lower protrusion 26b Fixing block 32 Main body 32a Rib-shaped protrusion 34 Concrete flange 36 Plate 40A, 40B Strut 42, 44A, 44B, 142 Cast-in-place concrete block 52 External cable

Claims (4)

In the corrugated steel web bridge in which a box girder extending in the bridge axis direction is formed by a pair of left and right corrugated steel webs connecting the upper floor slab and the lower floor slab,
In the state in which the upper floor slab is arranged with a plurality of precast ribs extending in a direction perpendicular to the bridge axis at predetermined intervals in the bridge axis direction, and a plurality of precast plates are bridged between the precast ribs. It is formed by placing concrete on top of
A plurality of struts having an upper end connected to the precast rib and a lower end connected to the lower floor slab are provided in the cross section of the bridge axis including the precast ribs in the internal space of the box girder. And
As the plurality of struts, an upper end portion is connected to the precast rib at a central portion in a bridge axis orthogonal direction in the box girder portion, and a lower end portion is connected to a portion near the connection portion with the corrugated steel web in the lower floor slab. A pair of struts and an upper end connected to the precast rib at a central portion of the box girder in the direction perpendicular to the bridge axis, and a lower end of the lower girder at the central portion of the box girder in the direction perpendicular to the bridge axis. A strut connected to the plate,
Each of the precast ribs is divided into two at the central portion of the box girder in the direction orthogonal to the bridge axis, and the pair of precast ribs divided into two are arranged at a predetermined interval from each other,
A corrugated steel web , wherein a cast-in-place concrete block is placed in a space between the pair of precast ribs, and upper ends of the plurality of struts are connected to the cast-in-place concrete block. bridge. In bridge axis perpendicular section including the above-described pre-cast ribs on the upper surface of the lower deck, the rib-like projections extending in the bridge axis perpendicular direction is formed, corrugated steel web bridge according to claim 1, wherein the . The corrugated steel web bridge according to claim 1 or 2, wherein a plurality of notches for installing the plurality of precast ribs are formed at an upper end of each corrugated steel web. 4. A corrugated steel web bridge according to claim 3 , wherein a plate for mounting the precast rib is attached to the bottom of each notch.

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