JP5548749B2 - Continuous girder bridge - Google Patents

Description

  The present invention includes a mixed girder in which a steel girder portion having a main girder made of steel and a PC girder portion having a main girder made of prestressed concrete (PC) are joined in the span axis direction in the bridge axis direction. Concerning continuous girder bridges.

  The mixed girder has a structure in which the steel girder part and the PC girder part are joined in the span axis direction in the span axis part. When this is applied to the continuous girder bridge, the span length is long or short Even so, it is possible to balance the stress between the branches. For example, in a three-span continuous girder bridge with a long center span length, a light and excellent work girder is placed between the center diameters, and a heavy mixed girder is placed between the side diameters. Therefore, it is possible to balance the stress while suppressing the bridge length.

  On the other hand, in such a mixed girder, it is necessary to smoothly transfer stress between the steel girder part and the PC girder part without causing stress concentration at the joint between the steel girder part and the PC girder part. It becomes.

  For this reason, conventionally, as described in, for example, “Patent Document 1”, a new PC structure is provided in a cross girder located at a joint between a steel girder part and a PC girder part in a mixed girder, thereby providing a steel girder. A device has been devised to smoothly transfer the stress between the PC girder and the PC girder.

  FIG. 7: is a figure which shows the junction part of the steel girder part and PC girder part in the said conventional mixed girder in the side cross section along a bridge axis direction.

  As shown in the figure, the joint 120C between the steel girder part 120A and the PC girder part 120B in the mixed girder 120 has a cellular shape in a portion near the steel girder part 120A in the cross girder 126 located in the joint part 120C. The steel shell portion 140 is formed, a plurality of PC steel materials 150 are arranged so as to extend in the bridge axis direction with respect to the cross beam 126, and these are tensioned, whereby prestress is introduced. ing. By providing such a PC structure, stress concentration is prevented from occurring in the joint 120C.

Japanese Patent Laid-Open No. 2003-232009

  However, in the conventional mixed girder 120, a new PC structure is provided in the cross beam 126 located at the joint 120C between the steel girder portion 120A and the PC girder portion 120B. PC steel 150 is required. Further, in order to fix the plurality of PC steel materials 150, it is necessary to increase the length of the cross beam 126 in the bridge axis direction to some extent, and the weight becomes considerably large. And since the steel-like steel shell part 140 is required, the steel weight becomes quite large. Furthermore, it is necessary to fill the steel shell 140 with concrete, but it is not easy to perform the construction.

  From the above, in the conventional mixed girder 120, the weight of the joining portion 120C between the steel girder portion 120A and the PC girder portion 120B becomes considerably large, and the construction of the joining portion 120C is enormous. There is a problem that it takes time and cost.

  The present invention was made in view of such circumstances, and in a continuous girder bridge having a mixed girder in which a steel girder part and a PC girder part are joined in the span axis direction in the bridge axis direction, It is an object of the present invention to provide a continuous girder bridge that can reduce the weight of the joint between the steel girder part and the PC girder part and can reduce the construction time and the construction cost.

  In the present invention, the above-mentioned object is achieved by adopting a PC structure using a PC steel material arranged in the main girder of the PC girder part as the joint part of the steel girder part and the PC girder part. .

That is, the continuous girder bridge according to the present invention is
In a continuous girder bridge having a mixed girder in which a steel girder having a main girder made of steel and a PC girder having a main girder made of prestressed concrete are joined in the span axis direction in the bridge axis direction,
The main girder part at the joint between the steel girder part and the PC girder part is configured as a steel-concrete composite part formed by placing concrete so as to bury the end of the main girder part of the steel girder part. Has been
In this steel-concrete composite part, a plurality of PC steel materials arranged in the main girder of the PC girder part are fixed.

  The “mixed digit” may have a single main digit, or may have a plurality of main digits.

  The specific configuration of the portion other than the main girder in the “steel girder” and “PC girder” is not particularly limited.

  The cross-sectional shape of the “steel main girder” is not particularly limited, and for example, an I-shaped cross section, a box-shaped cross section, or the like can be adopted.

  The cross-sectional shape of the “main girder made of prestressed concrete” is not particularly limited, and the concrete portion may be made of only concrete or reinforced concrete.

  The specific configuration and the number of arrangements of the “plurality of PC steel materials” are not particularly limited. Further, the specific fixing positions of these “plurality of PC steel materials” are not particularly limited.

  As shown in the above configuration, the continuous girder bridge according to the present invention includes a mixed girder in which the steel girder part and the PC girder part are joined in the bridge axis direction in the span portion, The main girder part at the joint between the steel girder part and the PC girder part is configured as a steel-concrete composite part formed by placing concrete so as to embed the end of the main girder part of the steel girder part. In this steel-concrete composite part, since a plurality of PC steel materials arranged in the main girder of the PC girder part are fixed, the steel girder part does not cause stress concentration in the joint part. In addition, the stress transmission between the PC girders can be performed smoothly.

  At that time, in the mixed girder according to the present invention, it is not necessary to provide a new PC structure in the cross girder positioned at the joint between the steel girder part and the PC girder part as in the prior art. Steel is not necessary. This also eliminates the need for fixing the plurality of PC steel materials, so that the length of the cross beam in the bridge axis direction can be significantly reduced to a structurally required length.

  Moreover, in the mixed girder according to the present invention, since the conventional steel-like steel shell portion is unnecessary, the steel weight can be greatly reduced, and further, the steel shell portion is filled with concrete. Since it is not necessary, the workability can be greatly improved.

  Therefore, according to the present invention, in a continuous girder bridge having a mixed girder in which the steel girder part and the PC girder part are joined in the span axis direction in the bridge axis direction, the joint part between the steel girder part and the PC girder part It is possible to reduce the weight and shorten the construction time and the construction cost.

  In the above configuration, if the fixing of the plurality of PC steel materials arranged in the main girder of the PC girder portion is performed at a plurality of locations in the bridge axis direction in the steel concrete composite portion, between the steel girder portion and the PC girder portion. Stress transmission can be performed more smoothly.

  In the above configuration, when the main girder of the steel girder is configured as a plate girder, the bottom surface of the steel-concrete composite portion is configured by the lower surface of the lower flange of the main girder, It is possible to prevent the concrete portion of the steel-concrete composite portion from being damaged by the positive bending moment generated at the joint portion with the PC girder portion.

  In this case, if the end part on the PC girder part side of the main girder part of the steel girder part is formed so that the upper flange is shorter than the lower flange, between the steel girder part and the PC girder part. Stress transmission can be performed more smoothly.

  Further, in this case, in a mixed girder in which the main girder of the steel girder part and the main girder of the PC girder part are displaced from each other in the direction orthogonal to the bridge axis, the lower flange of the main girder in the steel girder part However, at the position of the steel-concrete composite portion, the portion located on the main girder side of the PC girder portion with respect to the main girder web is configured to be relatively wide, and the steel of a plurality of PC steel materials If fixing to the concrete composite part is performed on the main girder side of the PC girder part rather than the main girder web in the steel girder part, the main girder of the steel girder part and the main girder of the PC girder part are connected to the bridge. Despite being displaced from each other in the direction perpendicular to the axis, a plurality of PC steel materials can be arranged without difficulty, and the stress transmission function between the steel girder part and the PC girder part can be sufficiently maintained.

The side view along the direction of a bridge axis showing the continuous girder bridge with the mixed girder concerning one embodiment of the present invention II-II sectional view of Fig. 1 Sectional view along line III-III in Fig. 2 Sectional view taken along line IV-IV in Fig. 2 The figure which shows one main girder in the above-mentioned mixed girder in the bridge axis orthogonal section in a plurality of places of the bridge axis direction The perspective view which shows the principal part of the said one main girder The figure similar to FIG. 4 showing a conventional example

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

  FIG. 1 is a side view along a bridge axis direction showing a continuous girder bridge 10 having a mixed girder 20 according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line II-II. 3 and 4 are sectional views taken along lines III-III and IV-IV in FIG.

  As shown in these drawings, the continuous girder bridge 10 is a three-girder continuous girder bridge having a long span between the center diameters, and a steel girder 12 is disposed between the center diameters, and the bridge shaft. The mixed beam 20 is arranged between the side diameters on both sides in the direction. Since each of the pair of mixed girders 20 has the same configuration, one of the mixed girders 20 will be described below.

  The mixed girder 20 according to the present embodiment has a double main girder structure in which an upper floor slab 24 is arranged at the upper end of a pair of left and right main girder 22. And this mixed girder 20 is the structure by which the steel girder part 20A which has the main girder 22A made from steel, and the PC girder part 20B which has the main girder 22B made from prestressed concrete were joined to the bridge axis direction in the span part. It has become.

  At that time, each main girder 22 of the mixed girder 20 is in a state where each main girder 22B of the PC girder part 20B is slightly displaced inward in the direction perpendicular to the bridge axis with respect to each main girder 22A of the steel girder part 20A. Is arranged in.

  Each main girder 22A of the steel girder 20A is configured as a plate girder including a web 22A1, an upper flange 22A2, and a lower flange 22A3. On the other hand, each main girder 22B of the PC girder 20B has an inverted trapezoidal cross-sectional shape.

  And the joint part 20C of the steel girder part 20A and the PC girder part 20B in the mixed girder 20 is concrete so that the pair of left and right main girder parts embed the end of each main girder 22A of the steel girder part 20A. Is constructed as a steel-concrete composite part 22C formed on the extension of each main girder 22B of the PC girder part 20B.

  Each steel-concrete composite part 22C has an inverted trapezoidal cross-sectional shape, like each main girder 22B of the PC girder part 20B. However, each steel concrete composite part 22C is formed wider than each main girder 22B of the PC girder part 20B, whereby each main girder 22B of the PC girder part 20B and each main girder of the steel girder part 20A. The displacement in the direction orthogonal to the bridge axis with 22A is absorbed.

  The concrete part in each main girder 22B of each steel concrete composite part 22C and PC girder part 20B is made of reinforced concrete (RC).

  A cross beam 26 made of reinforced concrete extending in the direction orthogonal to the bridge axis is arranged at the end of the joint 20C of the mixed beam 20 on the steel beam 20A side.

  The upper floor slab 24 is made of reinforced concrete, and a plurality of PC steel materials (not shown) are arranged in the direction perpendicular to the bridge axis. Further, a plurality of PC steel materials (not shown) are also arranged in the PC girder portion 20B of the upper floor slab 24 in the bridge axis direction.

  Since the mixed girder 20 according to the present embodiment has a bilaterally symmetric shape, one of the left and right pair of main girder 22 will be described below.

  FIG. 5 is a diagram showing one main girder 22 in a cross section orthogonal to the bridge axis at a plurality of locations in the bridge axis direction. Specifically, FIG. 4A is a cross-sectional view taken along the line Va-Va in FIG. 4, FIG. 4B is a cross-sectional view taken along the line Vb-Vb in FIG. 4, and FIG. 5 is a cross-sectional view taken along the line Vc-Vc in FIG. 4, and FIG. 4D is a cross-sectional view taken along the line Vd-Vd in FIG. FIG. 6 is a perspective view showing a main part of one main girder 22.

  As shown also in these drawings, the end of the main girder 22A of the steel girder 20A on the PC girder 20B side is formed so that the upper flange 22A2 is shorter than the web 22A1 and the lower flange 22A3. . Specifically, the web 22A1 and the lower flange 22A3 extend to the end position on the PC girder portion 20B side in the steel concrete composite portion 22C, and the upper flange 22A2 is a substantially center in the bridge axis direction of the steel concrete composite portion 22C. Extends to position.

  At the end of the main beam 22A of the steel beam portion 20A on the PC beam portion 20B side (that is, the portion embedded in the steel concrete composite portion 22C), both surfaces of the web 22A1, the upper surface of the upper flange 22A, and the lower flange thereof are provided. A plurality of stud dowels 28 are provided on the upper surface of 22A3. The plurality of stud gibels 28 are disposed so as to be relatively dense at a position close to the end face 22C1 on the steel girder portion 20A side in the steel concrete composite portion 22C.

  The main girder 22A of the steel girder portion 20A has a relatively wide lower flange 22A3 at the end portion on the PC girder portion 20B side and in the vicinity thereof, the portion located on the inner side in the direction perpendicular to the bridge axis than the web 22A1. It is formed as follows. At this time, the position of the edge on the inner side in the bridge axis orthogonal direction on the lower flange 22A3 is set to the same position as the edge on the inner side in the bridge axis orthogonal direction on the lower end surface of the main beam 22B of the PC girder 20B.

  The steel-concrete composite portion 22C, which is the main girder portion of the joint portion 20C, has a wide inverted trapezoidal cross-sectional shape as described above, but its lower end surface is the bottom of the main girder 22A of the steel girder portion 20A. It is comprised by the lower surface of flange 22A3. And the lower end surface of the main girder 22B of the PC girder 20B is formed so as to be flush with the lower surface of the lower flange 22A3.

  A plurality of PC steel members 30 extending in the bridge axis direction are arranged on the main beam 22B of the PC beam part 20B. Fixing of the end portions of the plurality of PC steel materials 30 on the side of the steel girder portion 20A is performed at three locations in the bridge axis direction of the steel concrete composite portion 22C. At this time, the fixing of the plurality of PC steel materials 30 is performed on the inner side in the bridge axis orthogonal direction with respect to the web 22A1 of the main girder 22A in the steel girder portion 20A.

  Specifically, 20 PC steel materials 30 are arranged as a plurality of PC steel materials 30. At that time, the eight PC steel members 30 are arranged in a four-stage, two-row arrangement on the end surface 22C1 on the steel girder portion 20A side in the steel-concrete composite portion 22C. In addition, the remaining 12 PC steel members 30 are arranged in a 6-step and 1-row arrangement in each of the two fixing protrusions 22C2 and 22C3 that are formed to protrude from the inner wall surface in the bridge axis orthogonal direction of the steel-concrete composite portion 22C. It has been broken. These two fixing projections 22C2 and 22C3 are formed at positions where the length in the bridge axis direction of the steel-concrete composite portion 22C is divided into approximately three equal parts.

  As described in detail above, in the mixed girder 20 according to the present embodiment, the main girder portion in the joint portion 20C between the steel girder portion 20A and the PC girder portion 20B is the end portion of the main girder 22A of the steel girder portion 20A. Is formed as a steel-concrete composite portion 22C formed by placing concrete so as to be embedded, and in this steel-concrete composite portion 22C, a plurality of pieces arranged on the main girder 22B of the PC girder portion 20B. Since the PC steel material 30 is fixed, stress transmission between the steel beam portion 20A and the PC beam portion 20B can be smoothly performed without causing stress concentration in the joint portion 20C.

  At that time, in the mixed girder 20 according to the present embodiment, it is not necessary to provide a new PC structure in the cross girder located at the joint between the steel girder part and the PC girder part as in the prior art. PC steel is not required. This also eliminates the need for fixing the plurality of PC steel materials, so that the length of the cross beam 26 in the bridge axis direction can be greatly reduced to a length necessary for the structure.

  Moreover, in the mixed girder 20 according to the present embodiment, since a conventional steel shell portion is required, the steel weight can be significantly reduced, and further, the steel shell portion is filled with concrete. Since there is no need to do this, workability can be greatly improved.

  Therefore, according to the present embodiment, in the mixed girder 20 in which the steel girder portion 20A and the PC girder portion 20B are joined in the bridge axis direction at the span portion, the joint portion 20C can be reduced in weight and installed. Time can be shortened and construction costs can be reduced.

  In particular, the mixed girder 20 according to the present embodiment has a configuration in which fixing of a plurality of PC steel materials 30 arranged in the PC girder portion 20B is performed at a plurality of locations in the bridge axis direction in the steel concrete composite portion 22C. Therefore, the stress transmission between the steel beam part 20A and the PC beam part 20B can be performed more smoothly.

  Further, in the mixed girder 20 according to the present embodiment, the main girder 22A of the steel girder portion 20A is configured as a plate girder, and the lower end surface of the steel-concrete composite portion 22C is formed by the lower surface of the lower flange 22A3 of the main girder 22A. Therefore, it is possible to prevent the concrete portion of the steel-concrete composite portion 22C from being damaged by the positive bending moment generated at the joint portion 20C between the steel girder portion 20A and the PC girder portion 20B.

  Further, the mixed girder 20 according to the present embodiment is formed such that the end portion of the main girder 22A of the steel girder portion 20A on the PC girder portion 20B side has the upper flange 22A2 shorter than the lower flange 22A3. Therefore, the stress transmission between the steel girder part 20A and the PC girder part 20B can be performed more smoothly.

  In the mixed girder 20 according to the present embodiment, the main girder 22B of the PC girder 20B is slightly displaced inward in the direction perpendicular to the bridge axis with respect to the main girder 22A of the steel girder 20A. The main girder 22A is formed such that, at the position of the steel-concrete composite portion 22C, the lower flange 22A3 is relatively wide at the portion located on the inner side in the direction perpendicular to the bridge axis from the web 22A1, and Since the fixing of the plurality of PC steel materials 30 to the steel concrete composite portion 22C is performed on the inner side in the direction perpendicular to the bridge axis than the web 22A1, the plurality of PC steel materials 30 can be arranged without difficulty. The stress transmission function between the steel beam portion 20A and the PC beam portion 20B can be sufficiently maintained.

  Furthermore, in the mixed girder 20 according to the present embodiment, a plurality of stud divels 28 are provided in a portion embedded in the steel-concrete composite portion 22C at the end of the main girder 22A of the steel girder portion 20A on the PC girder portion 20B side. Therefore, the stress transmission between the steel girder 20A and the PC girder 20B can be more reliably performed.

  In the above embodiment, the web 22A1 has been described as extending to the same position as the lower flange 22A3 at the end of the main beam 22A of the steel beam 20A on the PC beam 20B side. Instead, the end of the web 22A1 on the PC girder 20B side may be configured to be inclined and extended from the upper flange 22A2 to the lower flange 22A3.

  Moreover, in the said embodiment, although demonstrated as what was provided with the some stud diver 28 in the embedding part to the steel concrete composite part 22C in the main girder 22A of the steel girder part 20A, these some stud divel 28 is provided. Instead, it is also possible to form a dowel by forming a plurality of small holes in the web 22A1, the upper flange 22A, or the lower flange 22A3 located in the embedded portion of the main girder 22A.

  Further, in the above embodiment, the main girder 22B of the PC girder 20B has been described as being displaced inward in the direction perpendicular to the bridge axis with respect to the main girder 22A of the steel girder 20A. Even when the girder 22B is displaced outward in the direction perpendicular to the bridge axis with respect to the main girder 22A of the steel girder part 20A, the configuration of the main girder 22 includes the arrangement of the plurality of PC steel members 30 and the steel girder part 20A. If it is set as the structure which has a symmetrical shape regarding web 22A1 of main girder 22A in this, the effect similar to the said embodiment can be acquired.

  In addition, even when the main girder 22A of the steel girder 20A and the main girder 22B of the PC girder 20B are arranged on a straight line, by adopting the configuration of the above-described embodiment, the same effect as that of the above-described embodiment. Of course, the effect is obtained. At that time, it is possible to fix the plurality of PC steel materials 30 on both the left and right sides of the steel-concrete composite portion 22C.

  Further, the mixed girder 20 according to the above embodiment has been described as having a pair of left and right main girder 20, but when the main girder 20 is single, or there are three or more main girder 20. Even in some cases, by adopting the configuration of the above embodiment, it is possible to obtain the same operational effects as the above embodiment.

10 Continuous Girder Bridge 12 Steel Girder 20 Mixed Girder 20A Steel Girder Part 20B PC Girder Part 20C Joint Part 22, 22A, 22B Main Girder 22A1 Web 22A2 Upper Flange 22A3 Lower Flange 22C Steel Concrete Composite Part 22C1 End Face 22C2, 22C3 Fixing Projection 24 Upper floor slab 26 Horizontal girder 28 Stud gibber 30 PC steel

Claims (5)

In a continuous girder bridge having a mixed girder in which a steel girder having a main girder made of steel and a PC girder having a main girder made of prestressed concrete are joined in the span axis direction in the bridge axis direction,
The main girder part at the joint between the steel girder part and the PC girder part is configured as a steel-concrete composite part formed by placing concrete so as to bury the end of the main girder part of the steel girder part. Has been
In this steel-concrete composite part, a plurality of PC steel materials arranged in the main girder of the PC girder part are fixed.   The continuous girder bridge according to claim 1, wherein the fixing of the plurality of PC steel materials is performed at a plurality of locations in the bridge axis direction in the steel concrete composite portion. The main girder of the steel girder is configured as a plate girder,
The continuous girder bridge according to claim 1 or 2, wherein the lower surface of the steel-concrete composite portion is constituted by the lower surface of the lower flange of the main girder.   The continuous girder bridge according to claim 3, wherein an end of the main girder of the steel girder on the side of the PC girder is formed so that the upper flange is shorter than the lower flange. . The main girder of the steel girder part and the main girder of the PC girder part are arranged in a state displaced from each other in the direction perpendicular to the bridge axis,
The lower flange of the main girder in the steel girder is formed so that the portion located on the main girder side of the PC girder is relatively wide with respect to the web of the main girder at the position of the steel concrete composite part. And
The fixing of the plurality of PC steel materials to the steel concrete composite part is performed on the main girder side of the PC girder part with respect to the main girder web in the steel girder part. 4 continuous girder bridge.

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