JP2004270369A - Bridge structure and its construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bridge structure having high aseismicity and being constructed at a low cost in a short time of work and its construction method. <P>SOLUTION: The bridge structure 21 has a pair of abutments 22 and 23 installed in water at both sides of a river and an upper floor slab 24 stretched between upper ends of the abutments 22 and 23. The abutments 22 and 23 are formed of precast-concrete blocks, and both the abutments 22 and 23 are mounted on a water-bottom foundation 30 laid on the bottom of the river while the structure has a connecting bottom slab 26 composed of cast-in-place concrete connecting lower ends of both the abutments 22 and 23 and a fixing means 25 fixing both ends of the upper floor slab 24 at the upper ends of the abutments 22 and 23, respectively. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention mainly relates to a short bridge structure having a total length of 15 m or less and a construction method thereof.
[0002]
[Prior art]
Conventionally, a short bridge 1 having a total length of 15 m or less has a pair of abutments 2 and 2 installed on both sides of a river and an upper floor bridged between upper ends of both abutments 2 and 2, as shown in FIG. In many cases, the bridge 1 is configured with a plate 3. In this bridge 1, the end of the upper floor slab 3 is supported on a cast iron shoe seat 4 provided at the upper end of the abutments 2, via a buffer structure 5. By doing so, the stress acting on the abutments 2 and 2 due to an earthquake or the like, the load acting when a vehicle or the like passes over the upper floor slab 3, and the like are absorbed. (See, for example, Patent Document 1).
[0003]
In order to construct such a bridge, as shown in FIG. 17, as shown in FIG. 17, cut-off walls 10, 10 that cross the river with sheet piles or the like are constructed on the upstream and downstream sides of the river, and the construction space 11 that is impervious to water is constructed. Is formed, and concrete structures are cast in place in a dry construction space 11 that is impervious to water and a base structure such as a foundation pile and an abutment are cast in place. At this time, the water blocked on the upstream side flows down the downstream side by bypassing the temporary flow path 12 provided in the area adjacent to the river.
[0004]
[Patent Document 1]
JP-A-2002-371517
[Problems to be solved by the invention]
However, in the conventional bridge structure as described above, the portion supporting the end of the upper slab is located at the lower part of the upper slab, so that the cast iron shoe seat is rusted or the cushioning structure is damaged. There is a problem that it is difficult to understand even if it rolls up, and even if rust on the shoe seat or damage to the buffer structure is found, a scaffold for repair work is required to repair it There was a problem that labor and cost were required and it was difficult.
[0006]
In addition, in the conventional method for constructing a bridge structure as described above, a great deal of labor and time have to be spent for providing a temporary flow path for bypassing river water. There is a problem that the land must be rebuilt after the construction is completed, and there is also a problem that it is necessary to rent the land to establish a temporary flow path from the landowner of the adjacent land. On the other hand, in recent years, it is important to improve the construction environment by shortening the construction period in consideration of noise, vibration, and the like for residents near the construction site.
[0007]
An object of the present invention is to provide a bridge structure that has high earthquake resistance, can be constructed at low cost in a short construction period, and a method of constructing the same, in view of the state of the related art.
[0008]
[Means for Solving the Problems]
A bridge structure according to claim 1, which solves the conventional problems as described above and achieves an intended purpose, comprises a pair of abutments installed underwater on both sides of a river, and upper ends of both abutments. In a bridge structure including an upper floor slab bridged between the sections, the abutment is formed of a precast concrete block, and both abutments are installed on a water bottom foundation laid on the water bottom of the river, and A connection bottom plate made of cast-in-place concrete connecting the lower ends of the abutment, and fixing means for fixing both ends of the upper floor slab to the upper end of the abutment, respectively.
[0009]
With this configuration, the abutment, the upper slab, and the connecting bottom slab form an integral structure, and the entire bridge structure can cope with stress caused by an earthquake or the like. Therefore, labor and cost spent on maintenance are greatly reduced.
[0010]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, the abutment is a tubular precast concrete block including a top plate, a bottom plate, and both side wall plates.
[0011]
By configuring in this way, construction is easy, and even if the distance between the abutments is not wide, the water flow area of the river hardly changes, so that the water level does not change, and it is composed of the inside of the abutment, both abutments, and the connection bottom. Since the river water flows down through the culvert structure, the whole structure is in a stable state and high seismic resistance can be obtained.
[0012]
According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, a support portion for supporting the lower surface of the end portion of the upper floor slab is integrally provided on opposing surfaces of both abutments.
[0013]
With such a configuration, the upper floor slab can be suitably supported and fixed.
[0014]
According to a fourth aspect of the present invention, in addition to the configuration of the first, second or third aspect, the fixing means is formed by projecting an anchor bolt on an upper surface of the abutment or the support portion.
[0015]
With this configuration, the end of the upper floor slab can be suitably fixed to the upper end of the abutment with a simple structure.
[0016]
According to a fifth aspect of the present invention, in addition to the configuration of the first, second, or third aspect, the fixing means tensions the upper ends of both abutments and both ends of the PC tensile member that has penetrated the upper floor slab. The two abutments are fixed at the upper ends.
[0017]
With this configuration, the end of the upper slab can be suitably fixed to the abutment, and the upper slab can obtain high strength against bending stress.
[0018]
The construction method of a bridge structure according to claim 6 forms a watertight construction space with a pair of cutoff walls crossing a river and temporarily connects the upstream and downstream sides of the construction space. A bridge for constructing a bridge structure including a pair of abutments installed on both sides of a river and an upper floor slab laid over the upper ends of both abutments in the construction space with the flow path provided. In the method for constructing a structure, a part of a submarine foundation is laid at the bottom of the construction space in a state where a primary temporary flow path is formed by communicating between upstream and downstream cutoff walls on one side of the construction space. Then, after installing one abutment consisting of a cylindrical precast concrete block having a top plate, a bottom plate, and a side wall plate on the water bottom foundation, the primary temporary flow path is closed, and the upstream side of the construction space and Communication with the downstream side through the inside of the abutment To form a secondary temporary channel, form the remaining portion of the underwater foundation, install the other abutment on the underwater foundation, and then pour concrete to connect the lower ends of the abutments. And an end of the upper floor slab is fixed to upper ends of the abutments.
[0019]
With this configuration, the construction period can be significantly reduced, and the construction can be performed at low cost.
[0020]
According to a seventh aspect of the present invention, in addition to the configuration of the sixth aspect, the primary temporary flow path is provided with an impermeable wall extending in a downstream direction between the upstream cutoff wall and the downstream cutoff wall. A flow path is formed between the impermeable wall and one of the opposite quays.
[0021]
With such a configuration, it is possible to suitably provide the primary temporary flow path by utilizing the structure of the river.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of a bridge structure according to the present invention will be described.
[0023]
FIG. 1 shows a construction state of a bridge structure, wherein reference numeral 20 denotes a river bank, and reference numeral 21 denotes a bridge structure.
[0024]
The bridge structure 21 includes a pair of abutments 22 and 23 installed facing both sides of the river, that is, the quay 20a, and an upper floor slab 24 bridged between upper ends of the abutments 22 and 23. The ends of the upper deck 24 are fixed to the upper ends of the abutments 22 and 23 by fixing means 25, and the lower ends of both abutments 22 and 23 are connected by a connecting bottom plate 26.
[0025]
The abutments 22, 23 are, as shown in FIG. 2, composed of a rectangular cylindrical precast concrete block having a top plate 27, a bottom plate 28, and both side wall plates 29, 29, and on a water bottom foundation 30 laid on the water bottom of the river. It is to be installed in.
[0026]
The submarine foundation 30 includes a crushed stone layer 31 in which crushed stones are spread, and a foundation concrete 32 cast on the upper surface of the crushed stone layer 31.
[0027]
As shown in FIG. 3, the fixing means 25 is provided with anchor bolts 33 on the side portions of the abutments 22 and 23, and one end of the anchor bolts 33, that is, the bolt portion is protruded from the upper surface.
[0028]
The upper floor slab 24 is formed in a flat plate shape made of a precast concrete block, and both ends thereof are supported by upper ends of the abutments 22 and 23.
[0029]
At the end of the upper floor slab 24, a bolt layer through hole 34 penetrating in the thickness direction, a mounting recess 35 formed at the front end of the bolt insertion hole 34, and a bottom surface of the mounting recess 35 are formed. A base plate 36 embedded in the base plate 36, the base plate 36 has a bolt hole 37 communicating with the bolt insertion hole 34, and the bolt portion of the anchor bolt 33 is inserted through the bolt layer through hole 34 and the bolt hole 37. By screwing and tightening the nut 38, the upper floor slab 24 is fixed to the upper end portions of the abutments 22 and 23.
[0030]
The connection bottom slab 26 is formed into a flat plate having a reinforcing steel structure inside by cast-in-place concrete, and soil and sand are piled on the upper surface thereof and the upper surfaces of the bottom slabs of both abutments 22 and 23 to form a riverbed 40.
[0031]
In the bridge structure 21, the river water flows through both the abutments 22, 23 and the culvert structure 41 including the inner side wall plates 29, 29, the upper floor plate 24, and the connecting bottom plate 26 by the above-described structure. Is flowing down.
[0032]
Next, a method for constructing this bridge structure will be described with reference to FIGS.
[0033]
First, as shown in FIG. 4, cutoff walls 50 and 51 traversing the river with a sheet pile or the like are erected on the upstream side and the downstream side of the river with a portion where the bridge structure is to be constructed. The construction space 52 is formed.
[0034]
As shown in FIG. 5, the impermeable wall extends between the upstream cut-off wall 50 and the downstream cut-off wall 51 along the flowing direction at a position closer to one shore side than the center of the construction space 52. A temporary provisional passage 53 composed of a water impermeable wall 53, a water bottom and a quay wall 20 a is formed on one side of the construction space 52, and an upstream side of the construction space 52 is passed through the primary provisional passage 54. And the downstream side, and the water of the river flows down through the primary channel 54 to the downstream side.
[0035]
In this state, as shown in FIG. 6, the quay 20a and the water bottom are excavated, the construction space 52 is expanded, and the excavated and leveled water bottom is separated by a part of the water bottom foundation, that is, the impermeable wall 53. The water bottom foundation 30 is laid to the position where it was set.
[0036]
The underwater foundation 30 is formed by forming a crushed stone layer 31 by laying crushed stone on the excavated and leveled water bottom, and then casting a foundation concrete 32 by casting in place on the upper surface thereof.
[0037]
Next, as shown in FIG. 7, a rectangular cylindrical precast concrete block molded in advance at a factory or the like is hung at a predetermined position on the water bottom foundation 30, and the opening is oriented so as to face the downflow direction of the river. One abutment 22 is installed.
[0038]
Next, as shown in FIG. 8, a gutter-like shape is formed between the abutment 22, that is, between the upstream opening of the precast concrete block and the upstream cutoff wall 50, and between the downstream opening and the downstream cutoff wall 51. Are connected to each other through the inside of the abutment 22, that is, the precast concrete block, between the upstream side and the downstream side of the construction space 52 to form a secondary temporary flow path 56.
[0039]
On the other hand, the primary temporary flow path 54 is closed by the closing walls 50 and 51 to block water, and the water blocking wall 53 is removed.
[0040]
Then, as shown in FIG. 9, the construction space 52 is expanded by excavating the water bottom portion and the quay portion 20a of the portion constituting the primary temporary flow passage 54, and the remaining water bottom foundation 30 is formed on the excavated and leveled water bottom surface. Is formed continuously with a part of the submarine foundation 30 constructed in the above-described process, and the submarine foundation 30 is completed.
[0041]
Next, as shown in FIG. 10, the rectangular tubular precast concrete block is suspended at a predetermined position on the water bottom foundation 30, that is, at a position symmetrical to the abutment 22 via the center of the river, and the one pier 22 is Similarly, the other abutment 23 is installed so that the opening faces the downflow direction of the river.
[0042]
Then, as shown in FIG. 11, the upper deck 24 is bridged between the upper ends of the abutments 22 and 23 installed on both sides of the river, and the end of the upper deck 24 is fixed by the fixing means 25 to the upper ends of the abutments 22 and 23. To the part.
[0043]
That is, when the end of the upper floor slab 24 is placed on the upper surfaces of the abutments 22 and 23, the tips of the anchor bolts 33 projecting from the upper surfaces of the abutments 22 and 23 into the bolt layer through holes 34 and the bolt holes 37 at the ends of the upper floor slab. The ends of the upper floor slab 24 are fixed to the upper ends of the abutments 22 and 23 by threading and tightening the nut 38 with the screw portion at the tip of the anchor bolt.
[0044]
Then, as shown in FIG. 12, concrete is cast by casting to form a connecting bottom slab 26, and the lower ends of both abutments 22, 23 are connected.
[0045]
Then, as shown in FIG. 13, the bridge structure 21 is constructed by backfilling the earth and sand on the shore side of the abutments 22 and 23 and the earth and sand on the riverbed 40, paving or attaching a railing.
[0046]
Finally, the upstream cut-off wall 50 and the downstream cut-off wall 51 are removed, and the water is allowed to flow down to complete the operation.
[0047]
In the above-described embodiment, the example in which the abutment supports the upper floor slab on the upper surface has been described. In addition, as shown in FIG. 14, the support portion 61 is integrally formed on the opposite surface of the abutment 60, and The lower surface of the upper floor slab 24 may be supported by the support portion 61. At this time, the anchor bolt 33 constituting the fixing means 25 is made to protrude from the upper surface of the support portion 61.
[0048]
Further, in the above-described embodiment, the example in which the anchor bolt 33 is projected from the upper surface of the abutment 22, 23 or the support portion 61 as the fixing means has been described. However, as shown in FIG. The material 65 is passed through the abutment 60, the upper slab 24, and the abutment 60, and is fixed to the upper ends of both the abutments 60, 60 in a state where both ends of the PC tensile material 65 are tensioned. Good.
[0049]
【The invention's effect】
As described above, in the bridge structure according to the present invention, since the abutment, the upper floor slab, and the connecting bottom slab are integrally formed, the entire bridge structure can cope with stress due to an earthquake or the like, and the upper floor slab can be used. Since there is no need to provide a shoe seat or a buffer portion in the support portion, labor and cost for maintenance can be significantly reduced.
[0050]
Further, since the load acting on the upper deck is received by both abutments and the connecting bottom deck and the load is dispersed, the load acting on the foundation is small, and there is no need to provide a foundation pile or the like, so that the cost is low.
[0051]
Furthermore, since the upper slab is bridged between both abutments, it is possible to cope with the difference in river width only by changing the total length of the upper slab according to the river width.
[0052]
In addition, by constructing the abutment with a rectangular cylindrical precast concrete block, the construction is facilitated, and the water level does not rise even if the distance between both abutments is not widened.
[0053]
Furthermore, since the river water flows down through a culvert structure formed by the insides of the both abutments, the inner surfaces of the both abutments, and the connecting bottom slab, the weight of the river water makes the entire bridge stable and has high earthquake resistance.
[0054]
Further, according to the construction method according to the present invention, it is not necessary to dig deep into the river water bottom as in the case of burying a foundation pile or a lower end of an abutment, and a temporary flow path separate from the river is provided in the vicinity of the river. Since there is no need to provide them, the construction cost can be significantly reduced, the construction period can be significantly reduced, and the labor required for negotiations with neighboring residents can be reduced.
[0055]
Since the abutment is a precast concrete block, the installation work is facilitated, which also enables a reduction in construction cost and a shortened construction period.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an installed state of a bridge structure according to the present invention.
FIG. 2 is a perspective view showing a precast concrete block constituting the abutment according to the first embodiment.
FIG. 3 is a cross-sectional view showing an example of the fixing means.
FIG. 4 is a plan view showing a construction space construction step in the method for constructing a bridge structure according to the present invention.
FIG. 5A is a plan view showing a primary temporary channel building step of the above, and FIG. 5B is a sectional view of the same.
FIG. 6 is a cross-sectional view showing a submarine base laying step of the same.
FIG. 7 is a cross-sectional view showing an abutment installation step of the above.
FIG. 8A is a plan view showing a temporary flow channel switching step of the above, and FIG. 8B is a sectional view of the same.
FIG. 9 is a cross-sectional view showing a submarine base laying step of the above.
FIG. 10 is a cross-sectional view showing an abutment installation step of the above.
FIG. 11 is a sectional view showing an upper floor slab installation step of the above.
FIG. 12 is a cross-sectional view showing a connecting bottom slab casting step of the above.
FIG. 13 is a cross-sectional view showing a finishing step of the above.
FIG. 14 is a partially enlarged cross-sectional view showing another example of the bridge structure according to the present invention.
FIG. 15 is a sectional view showing another example of the fixing means.
FIG. 16 is a cross-sectional view showing a conventional bridge structure.
FIG. 17 is a plan view showing an example of a method for building a bridge structure according to the embodiment.
[Explanation of symbols]
Reference Signs List 20 shore portion 20a quay wall 21 bridge structure 22, 23 abutment 24 upper floor slab 25 fixing means 26 connecting bottom slab 27 top slab 28 bottom slab 29 side wall slab 30 water bottom foundation 31 crushed stone layer 32 foundation concrete 33 anchor bolt 34 bolt insertion hole 35 mounting recess 36 Base plate 37 Bolt hole 38 Nut 50 Upstream cut-off wall 51 Downstream cut-off wall 52 Construction space 53 Impermeable wall 54 Primary temporary flow path 55 Connection flow path 56 Secondary temporary flow path 60 Abutment 61 Support section 65 PC tensile member

Claims (7)

In a bridge structure comprising a pair of abutments installed underwater on both sides of a river, and an upper floor slab that is bridged between upper ends of both abutments,
The abutment is formed with a precast concrete block, and both the abutments are installed on a submarine foundation laid on the bottom of the river, and a connection bottom slab made of cast-in-place concrete connecting the lower ends of the both abutments, Fixing means for fixing both ends of the upper floor slab to the upper end of the abutment, respectively. The bridge structure according to claim 1, wherein the abutment is a cylindrical precast concrete block including a top slab, a bottom slab, and both side slabs. 3. The bridge structure according to claim 1, wherein a support portion for supporting a lower surface of an end portion of the upper floor slab is integrally provided on opposing surfaces of both abutments. 4. The bridge structure according to claim 1, 2 or 3, wherein the fixing means is formed by projecting an anchor bolt on an upper surface of the abutment or the support portion. 4. The fixing means according to claim 1, 2 or 3, wherein the fixing means is fixed to the upper ends of the both abutments in a state where the upper ends of the both abutments and both ends of the PC tensile material penetrating the upper floor slab are tensioned. The bridge structure as described. In the construction space, with a provisional flow path communicating between the upstream side and the downstream side of the construction space provided, while forming a construction space blocked by a pair of cut-off walls crossing the river, In a bridge structure construction method for constructing a bridge structure including a pair of abutments installed on both sides of a river, and an upper floor slab spanned over the upper ends of both abutments,
In a state where the primary temporary flow path is formed by communicating between the upstream and downstream cut-off walls to one side of the construction space, a part of the water bottom foundation is laid at the bottom of the construction space, and on the water bottom foundation After installing one abutment consisting of a tubular precast concrete having a top plate, a bottom plate and a side wall plate,
Along with closing the primary temporary channel, the upstream and downstream sides of the construction space are communicated through the inside of the abutment to form a secondary temporary channel, forming a remaining portion of the water bottom foundation, Install the other abutment on the underwater foundation,
Thereafter, an end of the upper floor slab is fixed to upper ends of the both abutments, and concrete is cast to form a connecting bottom slab connecting the lower ends of the both abutments. How to build. The primary temporary flow path is provided with an impermeable wall extending along the flowing direction between the upstream cutoff wall and the downstream cutoff wall, and a flow passage is formed between the impermeable wall and one of the opposing quay walls. The method for constructing a bridge structure according to claim 6, wherein

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