JP4167149B2 - Construction method of abutment accompanying bridge reconstruction - Google Patents

Description

The present invention relates to a building construction method of abutment with the bridge renovations.

  FIG. 5 is an explanatory view of a conventional construction method for an abutment associated with bridge reconstruction.

  Conventionally, when replacing a railway or road bridge in service with aging, first excavating the earth retaining wall behind the old abutment 101 after changing the position of the track and road. After securing sufficient space, temporarily holding the earth with the retaining wall 102 and the ground anchor 103, etc., and then placing the foundation pile 104 in the space vacated by the excavation, constructing the new abutment 105, The back of the new abutment 105 is backfilled with backfill soil 106. Therefore, by placing a new girder 107 on the new abutment 105, the girder is replaced and a new bridge is constructed.

  Hereinafter, the construction method of the abutment accompanying the conventional bridge reconstruction will be described in detail.

  FIG. 6 is a detailed process diagram of the abutment construction method associated with the conventional bridge reconstruction (part 1). FIG. 7 is a detailed process diagram (part 2) of the abutment construction method associated with the bridge reconstruction.

  (1) First, as shown in FIG. 6A, an old abutment 201 having a girder 203 and a foundation pile 202 is constructed, and this old abutment 201 is replaced.

  (2) Therefore, as shown in FIG. 6 (b), excavation is performed so as to take a wide space 205 on the back surface of the old abutment 201 having the girder 203 and the foundation pile 202. That is, (A) excavating a small stage, (B) generally installing a ground anchor to the temporary earth retaining wall of the excavation surface, repeating these steps (A) and (B), Excavation is performed to a predetermined depth, a temporary earth retaining wall 204 is placed, and temporary earth retaining work is performed.

  (3) Next, as shown in FIG. 6C, a new abutment 206 having a foundation pile 207 in a wide space 205 is constructed.

  (4) Next, as shown in FIG. 7D, the space between the back surface of the new abutment 206 and the temporary earth retaining wall 204 is backfilled with backfill soil 208. At that time, the temporary earth retaining work or the ground anchor may be removed as necessary.

(5) Next, as shown in FIG. 7 (e), the old abutment 201 having the girder 203 and the foundation pile 202 is removed,
(6) Next, as shown in FIG. 7 (f), a new girder 209 is placed on the new abutment 206. Then, restore the position of the track or road.

In order to efficiently reinforce a loose ground such as embankment, it is efficient to construct a temporary earth retaining work using a large-diameter reinforcing material. Regarding the construction method of the large-diameter reinforcing material, the following Patent Document 1, for the steep slope construction method of the embankment with the large-diameter reinforcing material, the following Patent Document 2, and for the construction method of the retaining wall using the large-diameter reinforcing material, the following Patent Document 3 has been proposed.
Japanese Patent No. 2575329 (page 2-3, FIG. 2) Japanese Patent No. 2653731 (page 2-3, FIG. 1) Japanese Patent No. 2832508 (page 3-4, FIG. 1)

  However, according to the conventional bridge replacement method described above, the construction method is cumbersome and the construction is unavoidable.

  In particular, according to the conventional bridge replacement method described above, since the new abutment 206 is installed behind the old abutment 201, the new bridge inevitably has a significantly longer girder 209 than the old bridge. . If the girder 209 becomes longer, the abutment 206 and its foundation also become larger. In particular, the design of recent structures has been designed in consideration of the time of a major earthquake, so there is a problem that a larger foundation is required.

In view of the above situation, the present invention suppresses the increase in length of the new bridge compared to the old bridge as much as possible in the construction of the abutment accompanying the bridge reconstruction, and uses a temporary earth retaining work as a part of the new abutment. Accordingly, an object of the invention to provide a building construction method of abutment with the bridge renovations capable of robust strength economically yet abutment.

In order to achieve the above object, the present invention provides
[1] In the construction method of the abutment accompanying the bridge reconstruction, (a) a retaining wall is placed on the back of the existing abutment, (b) a small step is excavated, and (c) the retaining wall on the excavation surface (D) Repeating the steps (b) and (c), excavating to a predetermined depth, and placing a tensile reinforcement (e) ) Install a foundation pile in the space vacated by excavation, (f) construct a new abutment by placing abutment concrete so as to connect with tensile reinforcement and retaining wall, and (g) remove the existing abutment (H) A new girder is built on the new abutment.

  [2] In the construction method of the abutment accompanying the bridge reconstruction described in [1], a space for the excavation is narrowed.

  [3] In the construction method of an abutment accompanying the bridge reconstruction described in [1] above, the foundation pile is reduced in number and mainly supports only a vertical load from a girder.

  According to the present invention, the following effects can be achieved.

  (1) In the conventional construction method, earth retaining having a ground anchor or the like is used. However, the ground anchor needs to be sufficiently examined for long-term use such as corrosion and loss of prestress. In addition, there are many unclear points in the behavior at the time of the earthquake, the number of use as a permanent structure is small, it is used as a temporary body to ensure stability only during construction, and the effect after completion of the abutment is expected. Absent. On the other hand, in the present invention, the earth retaining reinforced earth method is adopted as the earth retaining work, and the new earth abutment is integrated with the reinforcement earth retaining work, so that the reinforcing earth retaining work used during the temporary construction is the main body. Used as part of For example, in the case of the method shown in the above-mentioned Patent Document 2, the earth-and-ground reinforced earth method used here has many uses as a permanent structure, and the reinforced earth (temporary) earth retaining work used during the temporary construction is permanent. It can be something. Moreover, it is advantageous to make the strength of the abutment strong.

  (2) The conventional abutment requires a large foundation pile because it has a structure that resists the bending load rigidity of the foundation pile against a horizontal load such as an inertial force or earth pressure during an earthquake. Therefore, the foundation pile only needs to support mainly the vertical load from the girder, and can be resisted sufficiently with a smaller number of foundation piles than before.

  (3) Also, with regard to the abutment, since the conventional method has a cantilever structure, the cross-sectional force of the base part with the foundation pile is particularly large, and a large abutment cross section is required. Therefore, the cross-sectional force can be reduced, so that a smaller cross-section than the conventional one is sufficient.

  (4) Due to the above, the work space for constructing the new abutment can be reduced, the amount of excavation can be reduced, and as a result, the girder length can be shortened as compared with the conventional method. Further, in the conventional construction method, backfilling after the construction of the abutment is necessary, but in the present invention, backfilling is unnecessary and the labor of construction can be saved.

  In the construction method of the abutment accompanying the bridge reconstruction, (a) a retaining wall is placed on the back of the existing abutment, (b) a small step is excavated, and (c) a tension core against the retaining wall on the excavated surface. (D) Repeating the steps (b) and (c), excavating to a predetermined depth and placing a tensile reinforcement, (e) Install a foundation pile in the vacant space, (f) construct a new abutment by placing abutment concrete so as to be connected to the tension reinforcement and retaining wall, (g) remove the existing abutment, (H) A new girder is built on the new abutment. Compared to the old bridge, the new bridge can suppress the increase in length as much as possible and make the strength of the abutment strong.

  Hereinafter, embodiments of the present invention will be described in detail.

  First, the construction method of the abutment accompanying the bridge reconstruction of this invention is demonstrated.

  FIG. 1 is a cross-sectional view showing a situation during excavation of the construction method of the present invention, and FIG. 2 is a cross-sectional view showing a final construction state of the construction method of the present invention.

  According to the present invention, first, as shown in FIG. 1, earth retaining is performed by a reinforced earth method, and then, as shown in FIG. 2, an abutment is placed so as to embrace it. .

  Details will be described below.

(1) First, a retaining wall 4 (such as H steel, steel sheet pile, soil cement wall) is placed on the back of the old abutment 2 having the girder 3 and the foundation pile 1.
(2) After that, drilling a small stage,
(3) A tensile reinforcing material 5 such as nailing, micro-piling, or douring, in which a tensile core material is inserted, is placed on the earth retaining wall 4 on the excavation surface.

(4) The steps (2) and (3) are repeated to excavate to a predetermined depth, and the tensile reinforcing material 5 is placed,
(5) Install the foundation pile 6 in the space vacated by excavation,
(6) A new abutment 7 is constructed by placing abutment concrete so as to be connected to the tensile reinforcement 5 and the retaining wall 4.

(7) After that, the old abutment 2 and its foundation pile 1 were removed,
(8) Build a girder 8 on the new abutment 7.

  FIG. 3 is a cross-sectional view showing the abutment structure accompanying the bridge reconstruction constructed by the method of the present invention. Here, an example of an abutment using a large-diameter reinforcing material (dowling) as a tensile reinforcing material will be described.

  As shown in this figure, an abutment structure according to the present invention includes a retaining wall 12 having a large-diameter reinforcing member 11 and an abutment 14 having a foundation pile (H steel) 13 integrated with the retaining wall 12. And a girder 15 is mounted on the abutment 14.

  In this way, the large-diameter reinforcing material 11 is used, and the temporary earth retaining work is permanently installed, and the earth retaining wall 12 and the abutment 14 are integrated. In the event of an earthquake, the large-diameter reinforcing material 11 can share the earth pressure and the inertial force of the abutment 14 and the girder 15.

  FIG. 4 is a diagram showing analysis results by pushover (excessive pressing) of a static nonlinear model of an abutment of the present invention and a conventional abutment as a comparative example.

In this figure, ● is a conventional abutment (pile diameter 1.6 m), □ is a reinforced earth abutment (reinforcing length 8 m) using the large diameter reinforcing material of the present invention, the horizontal axis is the horizontal displacement (mm), the vertical axis It shows the horizontal seismic coefficient K _h.

  From this figure, it can be seen that the reinforced earth abutment of the present invention has a small horizontal displacement and can withstand a high horizontal seismic intensity as compared with the conventional abutment. In other words, such a reinforced earth abutment has sufficient deformation performance against level 2 (large-scale earthquake) ground motion, and if the reinforcement length is increased, higher earthquake resistance can be obtained.

  In addition, because it requires less backfill and foundation piles, it is excellent in workability and economy.

  From the above, it can be seen that the reinforced earth abutment of the present invention has good performance.

  As a result of performing vibration of 700 gal which is a seismic wave at the time of the Great Hanshin-Awaji Earthquake using a vibration testing machine, the reinforced earth abutment according to the present invention hardly deformed, but the conventional abutment caused a large deformation at 400 gal. It was.

  In this way, the reinforced abutment method allows the temporary earth retaining work to be installed on the back of the existing abutment to be permanently installed, and the earth pressure can be borne by the earth retaining work, and the abutment hardly bears the earth pressure. And the foundation pile can be greatly slimmed.

  The characteristics when the method of the present invention and the conventional method are compared are as follows.

  (1) In the conventional construction method, the retaining wall having a ground anchor or the like is a temporary body for ensuring stability only during construction, and an effect after completion of the abutment is not expected. On the other hand, in the construction method of the present invention, by integrating the abutment with the reinforcing earth retaining work, the reinforcing earth retaining work used during the temporary construction is used as a part of the main body. Can be reasonable.

  (2) The conventional abutment requires a large foundation pile because it has a structure that resists the bending load rigidity of the foundation pile against a horizontal load such as an inertial force or earth pressure during an earthquake. Therefore, the foundation pile only needs to support mainly the vertical load from the girder, and can be resisted sufficiently with a smaller number of foundation piles than before.

  (3) Also, with regard to the abutment, since the conventional construction method has a cantilever structure, the cross-sectional force at the base of the foundation is particularly large, and a large abutment is required. Therefore, the cross-sectional force can be reduced, so that a smaller cross-section than the conventional one is sufficient.

  (4) Due to the above, a work space for constructing a new abutment can be reduced, and as a result, the girder length can be shortened as compared with the conventional method. Further, in the conventional construction method, backfilling after the construction of the abutment is necessary, but in the construction method of the present invention, backfilling is unnecessary and the labor of construction can be saved.

  In addition, this invention is not limited to the said Example, A various deformation | transformation is possible based on the meaning of this invention, and these are not excluded from the scope of the present invention.

The present invention, in the renovation of such existing rack road bridge, is suitable for the construction method.

It is sectional drawing which shows the condition at the time of excavation of the construction method of this invention. It is sectional drawing which shows the final construction condition of the construction method of this invention. It is sectional drawing which shows the abutment structure accompanying the bridge reconstruction constructed | assembled by the construction method of this invention. It is a figure which shows the analysis result by the pushover (excessive press) of the static nonlinear model of the abutment of this invention, and the conventional abutment as a comparative example. It is explanatory drawing of the construction method of the abutment accompanying the conventional bridge reconstruction. It is the detailed process drawing (the 1) of the construction method of the abutment accompanying the conventional bridge reconstruction. It is the detailed process drawing (the 2) of the construction method of the abutment accompanying the conventional bridge reconstruction.

Explanation of symbols

1,6 Foundation pile 2 Old abutment 3,8,15 Girder 4,12 Earth retaining wall 5 Tensile reinforcement 7 New abutment 11 Large diameter reinforcement 13 Foundation pile (H steel)
14 Abutment

Claims (3)

(A) Placing a retaining wall on the back of the existing abutment,
(B) Excavate the small stage,
(C) A tensile reinforcement member in which a tensile core material is inserted is placed against the earth retaining wall of the excavation surface,
(D) The steps (b) and (c) are repeated to excavate to a predetermined depth, and a tensile reinforcement is placed.
(E) Install foundation piles in the space vacated by excavation,
(F) Build a new abutment by placing abutment concrete so as to connect with the tensile reinforcement and retaining wall,
(G) Remove existing abutments,
(H) A method for constructing an abutment associated with the reconstruction of the bridge, wherein a new girder is built on the new abutment.   2. The construction method of an abutment accompanying bridge reconstruction according to claim 1, wherein a space for the excavation is narrowed.   The construction method of an abutment accompanying bridge reconstruction according to claim 1, wherein the foundation pile is reduced in number and mainly supports only a vertical load from a girder.

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