JP4089451B2 - Abutment structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an abutment structure that supports a bridge end.
[0002]
[Prior art]
At both ends of the bridge, abutments that support the ends of the bridge superstructure are provided. There is soil on the back of this abutment and earth pressure acts on it, and generally the support ground is often deep. Even under such conditions, the abutment needs to be able to support the bridge stably under various load conditions such as seismic loads. Conventionally, for example, the structures shown in FIGS. 4 and 5 have been used as abutment structures that can satisfy such requirements. Here, FIG. 4 is a plan view showing a conventional abutment structure, and FIG. 5 is a VV cross-sectional view of FIG. 4 and 5, the abutment structure 2 includes a foundation pile 3 driven to the depth of the supporting ground, and an abutment body 7 including a footing 4, a hard wall 5, and a chest wall 6 supported by the foundation pile 3. Is done. The end of the bridge 9 is supported on the upper surface of the hard wall 5.
[0003]
In addition, for example, in Patent Document 1, precast concrete pillars (PC pillars) are placed on both banks of a river in a continuous wall shape, and the abutment body is built integrally with the PC pillars to install a sheet pile. Is disclosed to be unnecessary.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-330507
[Problems to be solved by the invention]
When constructing an abutment having a structure as shown in FIG. 4 and FIG. 5, the foundation pile 3 is placed and the bank 1 on the riverbank is removed, and then the temporary abutment is performed to construct the abutment body 7. At the time of this construction, the top end of the footing 4 is generally positioned below the riverbed, so it is necessary to make the temporary earth retaining also function as a river bank. Therefore, as shown in FIGS. 4 and 5, a large temporary closing work is required, such as a double closing where the river retaining wall is provided with a double sheet pile 8 and connected with a tie rod.
[0006]
Further, a large earth pressure acts on the abutment body 7 from the back side, and a large inertial force in the horizontal direction acts from the bridge 9 in the event of an earthquake. For this reason, it is necessary to construct a large-scale foundation pile 3 so as to resist these earth pressures and inertial forces.
[0007]
As described above, in the conventional abutment structure shown in FIGS. 4 and 5, the temporary closing work is large and the foundation pile 3 is also large, so that the construction period and construction cost of the abutment are increased.
[0008]
On the other hand, the abutment structure described in Patent Document 1 is configured to resist horizontal force using only a PC pillar. For this reason, the horizontal force that the abutment can bear is small, and it is considered difficult to use it as an abutment structure for a large-scale bridge.
[0009]
The present invention has been made in view of the above points, and an object of the present invention is to enable an abutment structure capable of bearing a large horizontal force to be constructed with relatively small construction.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an abutment structure according to the present invention includes a girder member that supports a bridge end portion, and the girder member is disposed in a horizontal plane at a position below the support position of the bridge end portion by the girder member. It is provided with the support pile which supports the inside so that a displacement is possible, and the reserve pile provided apart from this support pile to the abutment back side, and the said girder member being fixed.
[0011]
According to the present invention, since the support pile provided on the front side of the abutment bears only the vertical force, the support pile can be configured in a small scale. Moreover, since the reserve pile which bears a horizontal force is provided away from the support pile to the abutment back side, the ground between the support pile and the reserve pile can effectively resist the horizontal force. For this reason, a large horizontal resistance force can be obtained while keeping the scale of the reserve pile small. Furthermore, since the abutment structure of the present invention can be constructed by placing support piles and retaining piles and installing girder members, it is not necessary to break the entire levee as in the conventional construction method. For this reason, it is not necessary to perform a large-scale provisional deadline.
[0012]
In the present invention, the girder member may have a flat truss structure. In this way, the horizontal force in either the bridge axis direction or the direction perpendicular to the bridge axis is borne as the axial force of the truss member that constitutes the flat truss structure. Can be paid.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a plan view showing an abutment structure 10 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. As shown in FIG. 1 and FIG. 2, the abutment structure 10 of this embodiment includes a support pile 12, a retaining pile 14, and a girder support member 16 that is bridged between these piles. The girder member 16 has a flat truss structure in which a plurality of H-shaped steels 18 are joined together. Although FIG. 1 shows a case in which the girder member 16 is constituted by three triangular truss elements, the number of triangular truss elements constituting the girder member 16 is not limited to this. In the H-shaped steel 18 constituting the girder member 16, the upper flanges and the lower flanges are welded or bolted together via gussets at their respective joining points.
[0014]
The support pile 12 is provided along the side of the abutment front side of the girder support member 16 and supports the girder support member 16 with a pile vent structure. That is, the lower flange of the H-shaped steel 18 constituting the girder member 16 is placed on the upper end surface of the support pile 12, and only the force in the vertical direction is supported by the support pile 12, and freely slides and moves in the horizontal direction. Can be done. On the other hand, the holding pile 14 is provided along the side of the abutment back side of the girder member 16, and the lower flange of the H-shaped steel 18 is fixed to the upper end surface thereof by, for example, bolt joining. Therefore, as will be described later, the holding pile 14 bears a horizontal force acting on the girder member 16, and is configured to have a larger diameter than the support pile 12 that bears only the vertical force. In addition, as will be described later, the support pile 12 and the reserve pile 14 are provided at positions separated to such an extent that the soil of the ground existing between them exhibits a sufficient horizontal resistance force.
[0015]
The end of the bridge 20 is placed on the upper flange of the H-shaped steel 18 on the abutment front side of the girder member 16 (that is, the position above the support position of the girder member 16 by the support pile 12). In order to eliminate a step between the dike 22 and the bridge 20, a tread plate 24 is provided.
[0016]
When constructing the abutment structure 10, the upper portion of the embankment 22 is removed and the support pile 12 and the reserve pile 14 are driven. As a method for placing the support pile 12 and the reserve pile 14, a cast-in-place pile method may be used, or an existing pile method may be used. Next, the girder receiving member 16 is installed so as to be bridged between the support pile 12 and the retaining pile 14, and the H-shaped steel 18 on the abutment rear side of the retaining member 16 is joined to the upper end surface of the retaining pile 14. And the removal part of the embankment 22 is restored, and construction of the abutment structure 10 is completed.
[0017]
As described above, in the present embodiment, when the abutment structure 10 is constructed, it is only necessary to remove the upper part of the bank. For this reason, compared with the case where an abutment is constructed by breaking and excavating the embankment as in the conventional construction method, the abutment can be constructed by simple construction. And in this embodiment, it is not necessary to break the whole embankment, and since the construction part of the support pile 12 on the river side is above the water level, a large-scale temporary deadline such as a double deadline as in the conventional construction method is used. It becomes unnecessary, and it is only necessary to provide a small temporary deadline if necessary.
[0018]
Moreover, in the abutment structure 10 of this embodiment, it is set as the structure which supports only the force of a perpendicular direction with a pile vent structure with the support pile 12, and the support pile 12 does not bear the horizontal force by an earthquake etc., Therefore The scale of the support pile 12 Can be reduced. In addition, since the support pile 12 is almost entirely buried in the soil, the earth pressure carried by the support pile 12 is minimal, and the scale of the support pile 12 can be reduced in this respect.
[0019]
Thus, according to this embodiment, the abutment structure 10 can be constructed by a small-scale construction as compared with the conventional construction method.
[0020]
In addition, since the support pile 12 may have a small configuration as described above, it is possible to simplify the construction of the support pile 12 that is difficult to work because it is located on the slope portion of the embankment 22 and improve work efficiency. it can.
[0021]
In addition, since the support pile 12 and the reserve pile 14 are provided sufficiently apart from each other, a straight line drawn from the support pile 12 in the direction of the main collapse angle and the passive collapse from the reserve pile 14 as shown in FIG. The intersection P with the straight line drawn in the direction of the corner is above the ground surface. Only the soil below the intersection point P can resist the horizontal force, but when this intersection point P is above the ground surface, all the soil between the support pile 12 and the holding pile 14 Can resist the horizontal force, and a large resistance can be obtained. Thus, in this embodiment, since the support pile 12 and the reserve pile 14 are provided sufficiently apart from each other, the horizontal resistance force due to the soil of the ground is effectively obtained, and accordingly, the reserve pile 14 is reduced in size. It is possible to do everything. In FIG. 3, the starting point Q of the straight line in the direction of the main collapse angle and the starting point R of the straight line in the direction of the passive collapse angle when the intersection point P is determined are only applied to the ground force above these points Q and R. The point that can be effectively resisted can be obtained by analytical calculation.
[0022]
Furthermore, in this embodiment, a member having a plane truss structure is used as the girder member 16. For this reason, since any horizontal force in the direction of the bridge axis and the direction perpendicular to the bridge axis is transmitted as the axial force of the truss member (that is, the H-shaped steel 18) constituting the plane truss structure, the horizontal force in both directions is received by the girder member 16. Can be efficiently borne, and the girder receiving member 16 can be downsized. However, the girder member 16 in the present invention is not limited to the flat truss structure, and may be any structure that can resist horizontal force.
[0023]
【The invention's effect】
According to the present invention, an abutment structure capable of bearing a large horizontal force can be constructed with relatively small construction.
[Brief description of the drawings]
FIG. 1 is a plan view showing an abutment structure according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
FIG. 3 is a view for explaining the effect of separating the support pile and the reserve pile.
FIG. 4 is a plan view showing a conventional abutment structure.
5 is a cross-sectional view taken along line VV in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Abutment structure 12 Support pile 14 Retaining pile 16 Girder receiving member 18 H-shaped steel 20 Bridge

Claims (2)

A girder member that supports the bridge end, a support pile that supports the girder member in a position that is displaceable in a horizontal plane at a position below the support position of the bridge end by the girder member, and an abutment from the support pile An abutment structure characterized by comprising a retaining pile provided separately on the back side and to which the girder member is fixed. The abutment structure according to claim 1, wherein the girder member has a planar truss structure.

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