JP5074260B2 - Bridge erection method - Google Patents

Description

  The present invention relates to a bridge erection method in which a concrete bridge having a plurality of struts is erected by overhanging construction.

  2. Description of the Related Art Conventionally, as one type of concrete bridge, a structure in which a plurality of struts are arranged at a plurality of locations at predetermined intervals in the bridge axis direction is known. In that case, each strut in such a concrete bridge is connected to the overhanging slab at its upper end and connected to the main girder at its lower end.

  When constructing such a concrete bridge by overhanging construction, as described in, for example, “Patent Document 1” and “Patent Document 2”, a construction block at the time of overhanging construction is 1 It is common to set the struts to be included and place concrete for each of these construction blocks.

  And in this construction method by overhang construction, in each construction block, concrete striking is performed in a state where the struts are temporarily held by using the special strut construction stand supported by the mobile work vehicle together with the main girder construction stand. Is supposed to do.

  On the other hand, “Patent Document 3” describes a construction method in which a main girder is pre-constructed over a plurality of construction blocks, and then an overhanging slab and a plurality of struts are constructed.

JP 2004-190450 A JP 2005-188203 A JP 2001-164512 A

  The conventional erection method has the following problems.

  That is, in the erection methods described in “Patent Document 1” and “Patent Document 2”, a dedicated facility for temporarily holding the strut becomes large, and high installation accuracy is ensured when installing the strut. Since it is not easy, it takes a long period of time.

  On the other hand, the erection method described in “Patent Document 3” has a problem that the construction cost becomes high because erection facilities are required twice.

  The present invention has been made in view of such circumstances, and in a bridge erection method in which a concrete bridge having a plurality of struts is erected by overhanging construction, the construction period can be shortened and the construction cost can be reduced. The purpose is to provide a bridge erection method.

  The present invention is intended to achieve the above object by devising the shape of the boundary surface between the respective construction blocks during the overhang construction.

That is, the bridge erection method according to the present invention is:
A main girder, an overhanging slab that projects from the upper end of the main girder in a direction orthogonal to the bridge axis, and a plurality of positions arranged at predetermined intervals in the bridge axis direction, and the upper end is connected to the overhanging slab A bridge erection in which a concrete bridge comprising a plurality of struts whose lower ends are connected to the main girder is stretched and constructed for each predetermined construction block including one strut among the plurality of places. In the method
Each construction block is such that the concrete placement of the connecting portion with each strut in the main girder is performed one construction block ahead of the concrete placement of the connecting portion with the strut in the overhanging slab. The shape of the boundary surface between them is set to a predetermined uneven surface shape.

  The specific configuration of the “main girder” is not particularly limited, and for example, a box girder, an I girder, or the like can be adopted.

  The “overhanging floor slab” may be arranged only on one side in the direction perpendicular to the bridge axis with respect to the main girder, or may be arranged on both sides in the direction perpendicular to the bridge axis with respect to the main girder. May be.

  Each of the “struts” is not particularly limited in specific configuration such as material and cross-sectional shape as long as the upper end is connected to the overhanging slab and the lower end is connected to the main girder. . Further, the specific connecting positions of these “struts” to the overhanging slab and the main girder are not particularly limited. In addition, each of these “struts” has a structure in which the above-mentioned “extended floor slab” is arranged only on one side in the direction perpendicular to the bridge axis with respect to the main girder. However, if the above-mentioned "overhanging slab" is arranged on both sides of the main beam in the direction perpendicular to the bridge axis, the bridge shaft with respect to the main beam It may be configured to be disposed only on one side in the orthogonal direction, or may be configured to be disposed on both sides thereof.

  In the “predetermined length construction block”, the “predetermined length” may be set to the same value or a different value for each construction block.

  The above-mentioned "shape of the boundary surface between each construction block" is set to a predetermined uneven surface shape, but this "predetermined uneven surface shape" is the concrete placement of the connecting portion with each strut in the main girder. However, it is limited to a specific uneven surface shape as long as it can be realized to be performed one construction block ahead of the concrete placement of the connecting portion with the strut in the overhanging slab. It is not something. Moreover, this "shape of the boundary surface between each construction block" may be set to the same shape for every boundary surface, and may be set to a different shape.

  As shown in the above configuration, in the bridge erection method according to the present invention, a concrete bridge comprising a main girder, an overhanging slab, and a plurality of struts is laid out by overhanging for each predetermined length of construction block. However, at that time, the concrete placement of the connection portion with each strut in the main girder is performed by one construction block ahead of the concrete placement of the connection portion with the strut in the overhanging slab. Thus, since the shape of the boundary surface between each construction block is set to predetermined uneven surface shape, the following effects can be obtained.

  That is, when the strut is installed, since the connecting portion with the strut in the main girder is already formed, the strut can be temporarily installed by connecting the lower end portion of the strut to this connecting portion. For this reason, the temporary holding of the strut can be performed with a simple configuration, and this eliminates the need for large-scale equipment such as a dedicated stand for strut construction, which has been conventionally required for temporary holding of the strut. it can.

  In addition, at this time, since the concrete placement of the connecting portion with the strut in the overhanging slab has not yet been performed, the strut can be supplied from above the overhanging slab using the space of the unworked portion. . For example, struts can be supplied directly from the bridge surface in an existing construction block. And thereby, labor saving of construction can be achieved.

  The concrete placement of the connecting part with the strut (or the unfinished part including the connecting part with the strut) in this overhanging slab is carried out during the extension work of the next construction block, which completes the installation of the strut. Will be.

  And by adopting such a configuration of the invention of the present application, as in the other conventional examples, the main girder is preliminarily constructed over a plurality of construction blocks, and then installed in order to construct the overhang slab and the plurality of struts This eliminates the need for double installations, thereby reducing construction costs.

  Thus, according to the present invention, it is possible to shorten the construction period and reduce the construction cost in the bridge erection method in which a concrete bridge having a plurality of struts is erected by overhanging construction.

  In the above configuration, if the shape of the boundary surface between the respective construction blocks is set to an uneven surface shape in which the main girder is extended over the floor slab and is displaced by a predetermined length toward the front in the erection direction, A sufficiently wide space can be secured above the connecting portion of the beam with the strut. Therefore, the strut can be supplied very easily, and thus the temporary installation of the strut can be easily performed.

  Or in the said structure, the unevenness | corrugation which made the shape of the boundary surface between each construction block displace the connection part with the strut in an overhanging slab with respect to the other part in this construction block over a predetermined length to the overhanging direction back side. If the surface shape is set, it is sufficient that only a part of the overhanging floor slab is different from the shape of the boundary surface between each construction block in the normal overhanging construction. In addition, the overhanging of the overhanging slab can be easily performed.

  In this case, if an opening larger than the cross-sectional shape of the strut is formed in a portion of the overhanging slab located immediately above the intermediate portion of the strut, the overhanging floor is passed through this opening. The struts can be supplied from above the plate, whereby the struts can be temporarily installed.

  Further, in the above configuration, the shape of the boundary surface between the respective construction blocks is set such that the portion from the connecting portion with the strut in the overhanging slab to the vicinity of the main girder is extended with respect to the other portions of the construction block in the rearward direction If the concave and convex surface shape is displaced to the side by a predetermined length, both the overhanging construction of the main girder and the overhanging slab and the temporary installation of the struts can be facilitated to some extent. In particular, when the main girder is a box girder, the box girder portion can be constructed all at once, so that the construction efficiency can be increased.

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

  FIG. 1 is a perspective view showing a concrete bridge 10 to be installed in the bridge installation method according to an embodiment of the present invention in the course of installation, FIG. 2 is a partial sectional side view thereof, and FIG. FIG. 2 is a plan view and a cross-sectional view orthogonal to the bridge axis.

  As shown in these drawings, the concrete bridge 10 is a single box girder bridge made of prestressed concrete, and includes a U-shaped main girder 12 composed of a lower floor slab 12A and a pair of webs 12B, and the main girder. 12 comprises an upper floor slab 14 disposed at the upper end of 12 and a plurality of struts 16.

  In that case, the upper floor slab 14 includes a box girder forming portion 14A that forms a box girder structure with the main girder 12 by closing the upper end portion of the U-shaped main girder 12, and a pair of webs 12B in the main girder 12 respectively. It consists of a pair of overhanging floor slabs 14B projecting from the upper end of the bridge to both sides (right and left sides) in the direction perpendicular to the bridge axis.

  The plurality of struts 16 are arranged at a plurality of locations at predetermined intervals in the bridge axis direction. At that time, the plurality of struts 16 are respectively disposed on both sides of the main beam 12 at each of the plurality of locations.

  Each of these struts 16 is a precast concrete strut, and is arranged so as to extend obliquely upward in a plane orthogonal to the bridge axis. Each strut 16 has an upper end connected to the bridge axis orthogonal end of the overhanging slab 14B of the upper floor slab 14 and a lower end connected to the lower end of the web 12B of the main girder 12. Yes.

A strut receiving portion 14a is formed on the lower surface of the bridge axis orthogonal end portion of each overhanging slab 14B, and a strut receiving portion 12a is formed on the outer surface of the lower end portion of each web 12B. At that time, the strut receiving portion 14a of the overhanging slab 14B has a configuration having an opposing surface 14a1 that faces the fore end of the upper end portion of the strut 16, but the strut receiving portion 12a of each web 12B has a lower end of the strut 16. It is configured to have a recess 12a1 in which the part is accommodated.
In this embodiment, this concrete bridge 10 is constructed by overhanging every predetermined construction block B. At that time, the shape of the boundary surface P of each of these construction blocks B is set so that the construction block B includes a pair of left and right struts 16. In this embodiment, the shape of the boundary surface P between these construction blocks B is set to an uneven surface shape in which the main girder 12 is extended with respect to the upper floor slab 14 and displaced a predetermined length forward in the erection direction. .

  The construction block B located at the head of the plurality of construction blocks B is indicated by a two-dot chain line in FIGS. 1 and 2, and is indicated by a hatched area in FIG.

  FIG. 3A is a plan view showing the concrete bridge 10 immediately before the construction block B located at the head is constructed, and FIG. 3B is a concrete bridge immediately after the construction block B located at the top is constructed. 10 (c) is a cross-sectional view taken along the line cc of FIG. 10 (a), and FIG. 10 (d), FIG. 10 (e), and FIG. FIG. 5 is a sectional view taken along line dd, ee, and ff.

  When laying the concrete bridge 10, the temporary construction of the pair of left and right struts 16 is carried out in the construction block B where the construction work B was carried out immediately before the construction block B located at the head is constructed. Do. This temporary installation is performed by connecting the lower end portion of the strut 16 to the strut receiving portion 12a of the lower end portion of the web 12B in the main girder 12 protruding forward in the overhanging construction direction in the existing construction block B. In this connection, the strut 16 is suspended from above the upper floor slab 14 by a crane or the like (not shown), and the strut 16 is inclined at a predetermined angle, and its lower end is inserted into the recess 12a1 of the strut receiving portion 12a. To do. And the strut 16 temporarily installed in this way is temporarily held using a simple gantry (not shown).

  Then, after placing a formwork (not shown) in the part of the construction block B located at the top and performing predetermined reinforcement, concrete placement is performed. At this time, the upper end of the strut 16 is connected to the extended floor slab 14B in a state where the fore end of the strut 16 is positioned on the opposing surface 14a1 of the strut receiving portion 14a of the extended floor slab 14B. To complete.

  And the prestress of a bridge axis direction is introduce | transduced into the construction block B formed by this concrete placement, and the overhang construction is completed.

  Thereafter, the overhang construction is continued by repeating the same overhang construction for the next construction block B.

  As described above in detail, in the bridge erection method according to the present embodiment, the concrete bridge 10 configured as a single box girder bridge including a plurality of struts 16 is overlaid for each construction block B having a predetermined length. In this case, the concrete placement of the connecting portions of the web 12B of the main girder 12 with the struts 16 of the main girder 12 is performed in the connecting portions of the overhanging floor slab 14B of the connecting portions with the struts 16. The shape of the boundary surface P between the respective construction blocks B is set to the front side in the overhanging direction with the main girder 12 overhanging the floor slab 14B so as to be performed one concrete block ahead of the concrete placing. Since it is set to the uneven surface shape that is displaced long, the following effects can be obtained.

  That is, when the strut 16 is installed, since the connecting portion of the web 12B of the main girder 12 to the strut 16 is already formed as the strut receiving portion 12a, the lower end portion of the strut 16 is connected to the strut receiving portion 12a. By doing so, the strut 16 can be temporarily installed. For this reason, the temporary holding of the struts 16 can be performed with a simple configuration, thereby eliminating the need for a large-scale dedicated facility for strut construction as in the prior art.

  In addition, at this time, since the concrete placement of the strut receiving portion 14a which is the connecting portion with the strut 16 in the overhanging slab 14B has not been performed yet, the space of the unworked portion is used to make the extension of the overhanging slab 14B. The strut 16 can be supplied from above. Specifically, the struts 16 can be supplied directly from the bridge surface in the existing construction block B. And thereby, labor saving of construction can be achieved.

  The concrete placement of the unfinished portion including the strut receiving portion 14a in the overhanging slab 14B is performed at the time of the overhanging construction of the next construction block B, whereby the installation of the strut is completed.

  And by employ | adopting such a structure of this embodiment, an overhang | projection construction can be performed without requiring installation equipment twice, and this can suppress construction cost.

  As described above, according to the present embodiment, in the bridge erection method in which the concrete bridge 10 including the plurality of struts 16 is erected by overhanging construction, the construction period can be shortened and the construction cost can be reduced.

  In particular, in this embodiment, the shape of the boundary surface P between the respective construction blocks B is set to an uneven surface shape in which the main girder 12 is extended over the floor slab 14B and displaced forward by a predetermined length in the installation direction. Therefore, a sufficiently wide space can be secured above the strut receiving portion 12a in the web 12B of the main girder 12. Therefore, the supply of the struts 16 can be performed very easily, whereby the temporary installation of the struts 16 can be performed easily.

  In addition, in the said embodiment, although the case where each strut 16 was comprised with the precast concrete strut was demonstrated, also when comprised with steel struts etc., overhang | projection construction is carried out similarly to the said embodiment. By doing so, it is possible to obtain the same operational effects as in the above embodiment.

  Moreover, in the said embodiment, although the shape of the boundary surface P between each construction block B is set to the same shape in any boundary surface P, it can also set to a different shape suitably as needed. Is possible.

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

  FIG. 4 is a perspective view showing a concrete bridge 110 to be installed in the bridge installation method according to the first modification of the embodiment.

  As shown in the figure, the configuration itself of the concrete bridge 110 is the same as that of the concrete bridge 10 of the above embodiment, but the shape of the boundary surface P between the construction blocks B at the time of overhanging construction is the above embodiment. It is different from the case of.

  That is, in this modification, the shape of the boundary surface P between the respective construction blocks B is changed from the strut receiving portion 14a which is a connecting portion with the strut 16 in the overhanging slab 14B to other portions in the construction block B. On the other hand, it is set to have an uneven surface shape that is displaced by a predetermined length toward the rear side in the overhanging direction.

  In this modification, a sufficiently wide space cannot be secured above the strut receiving portion 12a in the web 12B of the main girder 12, but only a part of the overhanging floor slab 14B is placed between the construction blocks B in the normal overhanging construction. It is only necessary to make it different from the shape of the boundary surface P. Thus, the main girder 12 and the extended floor slab 14B can be easily extended.

  FIG. 5 is a perspective view showing a concrete bridge 210 to be installed in the bridge installation method according to the second modification of the embodiment.

  As shown in the figure, the configuration of the concrete bridge 210 and the shape of the boundary surface P between the respective construction blocks B at the time of the overhang construction are the same as those of the concrete bridge 110 of the first modified example, In this modification, an opening 14b larger than the cross-sectional shape of the strut 16 is formed in a portion of the overhanging floor slab 14B that is located directly above the intermediate portion of the strut 16.

  By forming the opening 14b in the overhanging slab 14B as in this modification, the struts 16 can be supplied from above the overhanging slab 14B through the opening 14b. 16 temporary installations can be performed easily.

  In addition, what is necessary is just to make this opening part 14b obstruct | occlude by performing concrete placement of the strut receiving part 14a in the overhanging slab 14B, or by performing concrete placement at another time.

  FIG. 6 is a perspective view showing a concrete bridge 310 to be installed in the bridge installation method according to the third modification of the embodiment.

  As shown in the figure, the configuration itself of the concrete bridge 310 is the same as that of the concrete bridge 10 of the above embodiment, but the shape of the boundary surface P between the construction blocks B at the time of overhanging construction is the above embodiment. It is different from the case of.

  That is, in this modification, the shape of the boundary surface P between the respective construction blocks B is the same as the part from the strut receiving portion 14a to the vicinity of the main girder 12 in the overhanging slab 14B, and the other part in the construction block B. On the other hand, it is set to have an uneven surface shape that is displaced by a predetermined length to the rear side in the overhanging direction.

  In this modification, a certain wide space can be secured above the strut receiving portion 12a in the web 12B of the main girder 12, whereby the strut 16 is supplied from above the overhanging slab 14B, and the temporary installation is performed. It can be done relatively easily. Moreover, in this modification, the main girder 12 and the box girder forming portion 14A of the upper floor slab 14 can be constructed at once, and thereby the overgrowth construction of the main girder 12 and the overhanging slab 14B is relatively easily performed. be able to.

The perspective view which shows the concrete bridge used as construction object in the state in the middle of construction in the bridge construction method which concerns on one Embodiment of this invention Partial cross-sectional side view showing the concrete bridge in the middle of construction A plan view and a cross-sectional view perpendicular to the bridge axis showing the concrete bridge in the middle of construction The same figure as FIG. 1 which shows the 1st modification of the said embodiment. The same figure as FIG. 1 which shows the 2nd modification of the said embodiment. The same figure as FIG. 1 which shows the 3rd modification of the said embodiment.

Explanation of symbols

10, 110, 210, 310 Concrete bridge 12 Main girder 12A Lower floor slab 12B Web 12a, 14a Strut receiving part 12a1 Recess 14 Upper floor slab 14A Box girder forming part 14B Overhanging slab 14a1 Opposing surface 14b Opening 16 Strut B Construction block P Interface

Claims (5)

A main girder, an overhanging slab that projects from the upper end of the main girder in a direction orthogonal to the bridge axis, and a plurality of positions arranged at predetermined intervals in the bridge axis direction, and the upper end is connected to the overhanging slab A bridge erection in which a concrete bridge comprising a plurality of struts whose lower ends are connected to the main girder is stretched and constructed for each predetermined construction block including one strut among the plurality of places. In the method
Each construction block is such that the concrete placement of the connecting portion with each strut in the main girder is performed one construction block ahead of the concrete placement of the connecting portion with the strut in the overhanging slab. A bridge construction method, characterized in that a shape of a boundary surface between each other is set to a predetermined uneven surface shape.   The shape of the boundary surface between the respective construction blocks is set to an uneven surface shape in which the main girder is displaced from the overhanging slab by a predetermined length in the overhanging direction front side. The bridge construction method according to Item 1.   The shape of the boundary surface between the construction blocks is an uneven surface shape in which the connecting portion with the strut in the overhanging slab is displaced by a predetermined length toward the rear side in the overhanging direction with respect to other portions of the construction block. The bridge construction method according to claim 1, wherein the bridge construction method is set.   4. The method of laying a bridge according to claim 3, wherein an opening larger than the cross-sectional shape of the strut is formed in a portion of the overhanging slab located immediately above the intermediate portion of the strut.   The shape of the boundary surface between the construction blocks is set so that the portion from the connecting portion with the strut in the overhanging slab to the vicinity of the main girder is extended to the rear side in the overhanging direction with respect to other portions of the construction block. 2. The method of laying a bridge according to claim 1, wherein the concavo-convex surface is displaced by a predetermined length.

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