JP4960731B2 - Seismic reinforcement structure for viaduct - Google Patents

Description

  The present invention relates to a viaduct seismic reinforcing structure mainly for railways.

  The substructure of a railway viaduct is usually constructed as a reinforced concrete ramen frame. However, when designing and constructing it, the seismic resistance of the viaduct during an earthquake must be fully considered. In particular, in the direction orthogonal to the bridge axis, it is necessary to sufficiently increase the rigidity in the same direction so that derailment of the train can be prevented.

  Under such circumstances, the applicant has been researching and developing a viaduct substructure in which a damper brace is arranged in a reinforced concrete ramen frame to improve seismic resistance.

  Here, when placing damper braces on existing viaducts, it is necessary to improve earthquake resistance not only on the part built on the ground but also on the underground part. And takes time.

  Therefore, the present applicant provides a new pile as an additional pile at a position separated from the existing pile supporting the frame structure, and braces the pile head of the increased pile and the vicinity of both ends of the beam or the vicinity of the head of the column. We have developed a seismic reinforcement structure that connects to each other via

JP 2001-020228 A JP 2004-270168 A

  According to the seismic reinforcement structure described above, the vertical load is supported by the existing pile as before, while the horizontal force during the earthquake can be partially transmitted to the pile through the brace, thus the viaduct. It is possible to seismically reinforce the substructure of not only the ground part but also the underground part.

  However, even with such a seismic reinforcement structure, the pile to be added has to be a large section pile, so there is still room for development in terms of economy.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a viaduct seismic reinforcement structure capable of seismic reinforcement not only in the ground part but also in the underground part of the lower structure.

  In order to achieve the above object, a viaduct seismic reinforcement structure according to the present invention comprises a pair of foundation beams arranged opposite to each other along the bridge axis direction of the viaduct and a pair of foundation beams as described in claim 1. The orthogonal foundation beams arranged so as to be orthogonal to each other are fastened in a rectangular shape or a ladder shape, and a pair of pillars erected so as to face each other in the vicinity of both ends of the orthogonal foundation beams and the heads of the pillars. A ramen frame is constructed with the passed beams, braces are arranged on the surface of the ramen frame, and steel sheet piles are buried in the ground at the sides of each foundation beam, and the heads of the steel sheet piles are Each is joined to each foundation beam.

  Further, the seismic reinforcement structure of the viaduct according to the present invention has a steel sheet pile installation region in the vicinity of the joint portion of the side of the foundation beam and the orthogonal foundation beam located immediately below the frame structure where the brace is arranged, A steel sheet pile non-installation region is defined as a vicinity of a joint portion with the orthogonal foundation beam positioned immediately below the ramen frame where the brace is not installed, and the steel sheet pile is installed only in the steel sheet pile installation region.

  In addition, the viaduct seismic reinforcement structure according to the present invention is such that the steel sheet pile is embedded in the ground at the side of the orthogonal foundation beam and the head of the steel sheet pile is joined to the orthogonal foundation beam.

  The seismic reinforcement structure for a viaduct according to the present invention includes a reinforced concrete floor slab constructed in a rectangular plane space surrounded by the foundation beam and the orthogonal foundation beam, and the reinforced concrete floor panel is tightly coupled to the foundation beam and the orthogonal foundation beam. It is a thing.

  Moreover, the viaduct seismic reinforcement structure according to the present invention is such that the brace is a damper brace.

  The present invention is intended for seismic reinforcement of a viaduct substructure formed of a ramen frame that is an above-ground part and a base structure of an underground part that supports the ramen frame. A pair of foundation beams arranged opposite to each other along the axial direction and an orthogonal foundation beam arranged so as to be substantially orthogonal to the pair of foundation beams are fastened in a rectangular shape or a ladder shape.

  In the present invention, steel sheet piles, also called sheet piles, are embedded in the ground at the sides of the pair of foundation beams, and the heads of the embedded steel sheet piles are joined to the foundation beams, respectively.

  In this way, the pulling force and compressive force caused by the rocking vibration of the entire rigid frame structure that occurs during the earthquake acts on the foundation structure via the columns of the rigid frame structure, but these pulling force or compressive force is applied to existing piles. The head is supported by a steel sheet pile joined to the foundation beam. In other words, the pulling force and compressive force transmitted from the column of the rigid frame are supported by the peripheral frictional force between the pile and the surrounding ground, and also supported by the frictional force between the steel sheet pile and the surrounding ground. It becomes.

  Therefore, in combination with the seismic reinforcement effect of the braces arranged on the ramen frame, it is possible to greatly enhance the seismic reinforcement effect of the entire viaduct substructure.

  A rigid frame is composed of a pair of columns erected so as to face each other in the vicinity of both ends of an orthogonal foundation beam, and a beam spanned over the head of the column. When the brace is arranged on the plane of construction, the horizontal rigidity of the viaduct substructure along the direction orthogonal to the bridge axis is improved.

  The braces need not be placed on every frame frame, but can be selectively placed for the required degree of seismic resistance or other reasons. For example, it is conceivable to place a brace by skipping one. In the present specification, the term “brace” is used in a broad sense as a concept that encompasses a damper brace incorporating a damper mechanism in addition to a narrowly defined brace.

  The steel sheet piles are respectively embedded in the sides of a pair of foundation beams arranged opposite to each other along the bridge axis direction of the viaduct, and their heads are respectively joined to the foundation beams. The steel sheet pile and the foundation beam can be joined with any structure as long as the pulling force or compression force transmitted from the column of the rigid frame is transmitted to the steel sheet pile. Also, it can be a pin joint.

  As mentioned above, the steel sheet pile supports the pulling force and compressive force caused by the rocking vibration of the entire rigid frame structure that occurs during the earthquake, but when the pulling force is generated in one column, it is compressed in the other column. Since a force is generated, the steel sheet pile is installed on each side of one foundation beam and the other foundation beam of the pair of foundation beams.

  However, it is arbitrary whether the side of the foundation beam is installed on both sides or only on the side close to or far from the viaduct center, for example, when placed on the side far from the viaduct center, respectively. Is a two-row arrangement in which the distance between the steel sheet piles is the largest. On the other hand, when arrange | positioning at the both sides of each foundation beam, the steel sheet pile will be arrange | positioned in a total of 4 rows in two rows on the both sides of each foundation beam along a bridge-axis direction.

  Here, as long as the above-described pulling force and compressive force can be supported, how to set the installation length and installation position of the steel sheet pile along the bridge axis direction is arbitrary, for example, the steel sheet pile over the entire length of the foundation beam. Although it is conceivable to install, the steel sheet pile installation area is the vicinity of the side of the foundation beam where the brace is placed and the orthogonal foundation beam located directly below the frame structure, and the brace is not installed If the steel sheet pile non-installation area is the vicinity of the joint with the orthogonal foundation beam located directly below the frame frame, and the steel sheet pile is installed only in the steel sheet pile installation area, the location to improve the earthquake resistance of the viaduct substructure is Since the ground part and the underground part coincide, it is possible to perform an effective seismic reinforcement work with excellent economic efficiency.

  Moreover, the installation range of the steel sheet pile is not limited to the side of the foundation beam. That is, if the steel sheet pile is embedded in the ground at the side of the orthogonal foundation beam and the head of the steel sheet pile is joined to the orthogonal foundation beam, the earthquake resistance against the above-described pulling force and compressive force can be improved. In addition, the torsional rigidity around the vertical axis can be increased.

  Therefore, even if it is difficult to balance the installation of braces on ramen frames and steel sheet piles on the side of the foundation beam due to the surrounding environment, sky head height, and various other construction reasons, The torsional rigidity of the structure can be improved, and the torsion of the structure due to the eccentric arrangement can be suppressed.

  On the other hand, if a reinforced concrete floor slab is constructed in a rectangular planar space surrounded by the foundation beam and the orthogonal foundation beam and the reinforced concrete floor panel is tightly connected to the foundation beam and the orthogonal foundation beam, the foundation beam and the orthogonal foundation beam are passed through the reinforced concrete floor panel. Are integrated.

  Therefore, it is less necessary to match the location where the seismic resistance of the viaduct substructure is improved between the ground part and the underground part, and the place where the braces are placed and the place where the steel sheet piles are placed It becomes possible to decide individually according to the circumstances.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a viaduct seismic reinforcement structure according to the present invention will be described below with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.

  FIG.1 and FIG.2 is the figure which showed the earthquake-proof reinforcement structure of the viaduct concerning this embodiment. As can be seen from these figures, the viaduct seismic reinforcement structure 1 according to the present embodiment is a viaduct substructure formed by a ramen frame 4 that is an above-ground portion and a base structure 5 that is an underground portion that supports the ramen frame. 3 is the target of seismic reinforcement.

  As can be clearly seen in FIG. 2, the foundation structure 5 has a pair of foundation beams 6 and 6 arranged opposite to each other along the bridge axis direction of the viaduct and an orthogonal foundation beam arranged so as to be substantially orthogonal to the pair of foundation beams. 7 is formed in a ladder shape. The foundation structure 5 is continuously constructed along the bridge axis direction, and supports the superstructure 2 of the viaduct via the ramen frame 4 that is the ground part.

  The frame 4 is composed of a pair of pillars 8 and 8 erected so as to face each other in the vicinity of both ends of the orthogonal foundation beam 7, and a beam 9 spanned over the head of the pillar. Although provided for each orthogonal foundation beam 7, damper braces 12 are arranged on the two frame frames 4 on the orthogonal foundation beam 7 located at the end of the ladder-shaped foundation structure 5.

  The damper brace 12 is composed of a hysteresis damping damper 10 and brace bodies 11, 11. The two brace bodies 11, 11 are arranged in an inverted V shape in the plane of construction, and the lower ends thereof are leg portions of the columns 8, 8. The upper end is joined to the hysteresis damping damper 10 attached to the lower center surface of the beam 9.

  Here, the viaduct seismic reinforcement structure 1 according to the present embodiment embeds steel sheet piles 13 and 13, also called sheet piles, in the ground 14 on both sides of each foundation beam 6, thereby extending along the bridge axis direction. It is arranged in two rows on both sides of each foundation beam 6, for a total of four rows, and the heads of the embedded steel sheet piles 13, 13 are in rigid contact with each foundation beam 6.

  In order to construct the viaduct seismic reinforcement structure 1 according to this embodiment, a steel sheet pile 13 is first embedded in the ground 14. The steel sheet pile 13 may be rocked and pressed into the ground 14 with a vibro hammer, or may be driven into the ground 14 with a hydraulic hammer. In any case, the construction of the steel sheet pile 13 may be performed according to a conventionally known method.

  Here, if necessary, the construction position of the steel sheet pile 13 is separated from the foundation beam 6 by a certain distance so that the joining work with the foundation beam 6 is possible. Hereinafter, in the present embodiment, a case where the steel sheet pile 13 is embedded by being separated from the foundation beam 6 by a certain distance and the separated space is used as a joint space between the head of the steel sheet pile 13 and the foundation beam 6 will be described.

  Next, the ground spreading between the steel sheet pile 13 and the foundation beam 6 is dug into a groove shape to expose the foundation beam 6, and a joining work space between the steel sheet pile 13 and the foundation beam 6 is secured.

  Next, a concrete anchor is driven into the foundation beam 6 so as to protrude into the joining work space, and a stud is similarly welded to the head of the steel sheet pile 13.

  Next, reinforcing bars are arranged in the joining work space as necessary, and then concrete is placed in the joining work space.

  In the seismic reinforcement structure 1 of the viaduct according to the present embodiment, as shown in FIG. 3, the horizontal frame force caused by the earthquake acting on the lower structure 3 from the upper structure 2 at the time of the earthquake, and hence the entire frame structure 4 caused by the horizontal force during the earthquake. Due to the rocking vibration, the pulling force and compressive force act on the foundation structure 5 via the columns 8 and 8.

  Here, the steel sheet pile 13 is in contact with the ground 14 with an area of installation length W × embedding depth D. Therefore, in addition to the peripheral surface friction force by the existing pile 15, the drawing force and the compression force are reliably supported by a large friction force generated between the steel sheet pile 13 and the surrounding ground.

  As described above, according to the viaduct earthquake-proof reinforcement structure 1 according to the present embodiment, the pulling force and the compressive force caused by the rocking vibration of the entire rigid frame 4 generated at the time of the earthquake are applied to the columns 8 and 8 of the rigid frame 4. The pulling force or compressive force is supported by the existing pile 15 and the head is supported by the steel sheet pile 13 joined to the foundation beam 6. In other words, the pulling force and compressive force transmitted from the column 8 of the rigid frame 4 are supported by the circumferential frictional force between the pile 15 and the surrounding ground, and also by the frictional force between the steel sheet pile 13 and the surrounding ground. Will be supported.

  Therefore, in combination with the seismic reinforcement effect of the damper brace 12 arranged on the rigid frame 4, it becomes possible to seismically strengthen the lower structure 3 of the viaduct as a whole.

  In the present embodiment, the damper brace 12 in which the hysteresis damping damper 10 is incorporated is adopted as the brace. However, it is optional whether or not the damper is incorporated, and the brace may be configured only by the brace body 11. Absent. In such a case, the top of the brace body 11 is configured to be in rigid contact with the lower surface of the beam 9.

  Moreover, in this embodiment, although the steel sheet pile 13 was installed in the both sides of the foundation beam 6, it may replace with this and may install in only one of the side near a viaduct center, or a distant side.

  FIG. 4 shows a modification in which the steel sheet pile 13 is installed only on the side farther from the viaduct center among the sides of the foundation beam 6.

  In the present embodiment, the damper brace 12 is provided only on the rigid frame 4 just above the orthogonal foundation beams 7 and 7 positioned at both ends of the foundation structure 5. A damper brace 12 may also be provided on the rigid frame 4 of the orthogonal foundation beam 7 located at the position.

  Further, in this embodiment, the steel sheet pile 13 and the foundation beam 6 are joined rigidly, but instead of this, a pin joint or a semi-rigid joint may be used. The construction method for joining the part and the foundation beam 6 is arbitrary, and the optimum joining method is appropriately selected as long as the tensile force or compressive force from the column 8 can be supported by the friction force between the ground 14 and the steel sheet pile 13 do it.

  Moreover, in this embodiment, although the steel sheet pile 13 was installed over the full length of the foundation beam 6, it is good also as a structure shown instead of this in the modification of FIG.

In the modified example shown in the figure, a steel sheet pile installation region Z ₁ is set in the vicinity of a joint portion of the side of the foundation beam 6 with the orthogonal foundation beam 7 located immediately below the rigid frame 4 where the damper brace 12 is disposed. The vicinity of the joint with the orthogonal foundation beam 7 positioned immediately below the rigid frame 4 where the damper brace 12 is not installed is a steel sheet pile non-installation area Z ₀ , and the steel sheet pile 13 is installed only in the steel sheet pile installation area Z _1. .

  If comprised in this way, the location which improved the earthquake resistance of the viaduct substructure 3 will correspond in an above-ground part and an underground part, and the efficient earthquake-proof reinforcement construction excellent in economy will be attained.

  6 to 8 show another modified example. In the modification according to the figure, a reinforced concrete floor board 62 is constructed in a rectangular plane space 61 surrounded by the foundation beam 6 and the orthogonal foundation beam 7, and the reinforced concrete floor board is tightly connected to the foundation beam 6 and the orthogonal foundation beam 7. is there.

  If comprised in this way, since the foundation beam 6 and the orthogonal foundation beam 7 will be integrated via the reinforced concrete floor board 62, it is necessary to make the location which improves the earthquake resistance of the viaduct substructure 3 correspond in an above-ground part and an underground part. Less.

  In other words, in the present modification, the damper brace 12 is disposed only on the rigid frame 4 just above the orthogonal foundation beam 7 located at the end of the foundation structure 5 as in the above-described embodiment, while the steel sheet pile 13 It arrange | positions only on the both sides of the rigid frame 4 which has arrange | positioned the brace 12, and it is not necessary to make the installation position of the damper brace 12 and the steel sheet pile 13 correspond.

  Therefore, it is possible to individually determine the location of the damper brace 12 and the location of the steel sheet pile 13 according to the circumstances such as the construction procedure, heavy equipment used, or interference.

  Moreover, in this embodiment, although the steel sheet pile 13 was provided only in the side of the foundation beam 6, this invention does not exclude providing a steel sheet pile in the side of an orthogonal foundation beam. FIG. 9 shows such a modification.

  As can be seen from the figure, in this modification, the orthogonal foundation sandwiching the rectangular planar space 91 located at the end of the foundation structure 5 out of the rectangular planar space 61 defined by a plurality of orthogonal foundation beams 7. Not only is the damper brace 12a provided on the frame 4 positioned directly above the beams 7 and 7, but also the damper braces 12b and 12b are provided on the frame 4 positioned directly above the foundation beams 6 and 6 sandwiching the rectangular planar space 91. It is. In addition to embedding steel sheet piles 13a, 13a in the ground 14 on both sides of the foundation beams 6, 6, not only joining the heads of the steel sheet piles to the foundation beams 6, 6, Steel sheet piles 13b, 13b are embedded in the ground 14 on both sides, and the heads of the steel sheet piles are joined to the orthogonal foundation beams 7, 7.

  In this configuration, as in the above-described embodiment, the frame 4 positioned directly above the orthogonal foundation beam 7, the damper brace 12 a disposed on the surface of the frame, and the steel sheet pile 13 a provided on the side of the foundation beam 6. Contributes to the improvement of the rigidity of the ground part and underground part of the lower structure 3 along the direction orthogonal to the bridge axis, but in addition to that, it is arranged on the frame 4 and the construction surface located immediately above the foundation beam 6. Further, the damper brace 12b and the steel sheet pile 13b provided on the side of the orthogonal foundation beam 7 contribute to the improvement of torsional rigidity around the vertical axis against the horizontal seismic force.

FIG. 10 is a conceptual diagram illustrating such an action. As can be seen from FIG. 10, when the rigid members such as the damper brace 12 and the steel sheet pile 13 are arranged eccentrically, the foundation structure 5 with respect to the horizontal force at the time of earthquake is shown. Is twisted around the rigid center G ₁ , but the torsion is resisted by the frictional force that the steel sheet pile 13 a receives from the surrounding ground (FIGS. (A) and (b)).

On the other hand, the case of providing a steel sheet pile 13b on the side of the orthogonal footing beams 7 with respect to seismic horizontal force, although basic structure 5 is also twisted Tsuyoshikokoro G ₂ around the steel sheet pile 13b is not only the steel sheet pile 13a In order to resist the torsion applied by the frictional force received from the surrounding ground (FIGS. (C) and (d)), the amount of twist is smaller than in the case of the steel sheet pile 13a alone.

  Therefore, the installation of the damper brace 12 on the ramen frame 4 and the installation of the steel sheet pile 13 on the side of the foundation beam 6 cannot be performed in a well-balanced manner, and as a result, the center of gravity on the plane and the stiffness are shifted. However, it becomes possible to improve the torsional rigidity around the rigid core and to suppress the torsion of the structure due to the eccentric arrangement.

The vertical sectional view of the seismic reinforcement structure of a viaduct concerning this embodiment. Similarly horizontal sectional view. The conceptual diagram which showed the effect | action of this embodiment. The vertical sectional view which showed the seismic reinforcement structure of the viaduct concerning a modification. The horizontal sectional view which follows the AA line. The horizontal sectional view which showed the seismic reinforcement structure of the viaduct concerning another modification. The vertical sectional view which follows a BB line. The vertical sectional view which follows CC line. The horizontal sectional view which showed the seismic reinforcement structure of the viaduct concerning another modification. The conceptual diagram explaining the effect | action of the modification.

Explanation of symbols

1 Seismic reinforcement structure of viaduct 2 Superstructure of viaduct 3 Lower structure of viaduct 4 Frame structure 5 Foundation structure 6 Foundation beam 7 Orthogonal foundation beam 8 Column 9 Beam 10 Hysteresis damper 11 Brace body 12 Damper brace (brace)
13, 13a, 13b Steel sheet pile 14 Ground 62 Reinforced concrete floor board

Claims (5)

A pair of foundation beams arranged opposite to each other along the bridge axis direction of the viaduct and an orthogonal foundation beam arranged so as to be substantially orthogonal to the pair of foundation beams are fastened in a rectangular shape or a ladder shape, and the orthogonal foundation beams A pair of columns erected so as to face each other in the vicinity of both ends of the frame and a beam spanned over the heads of the columns constitute a ramen frame, and a brace is disposed on the frame surface of the ramen frame; A steel bridge sheet pile embedded in the ground at the side of each foundation beam, and the head of the steel sheet pile was joined to each foundation beam. Of the sides of the foundation beam, the vicinity of the junction with the orthogonal foundation beam located immediately below the frame structure where the brace is arranged is a steel sheet pile installation region, and the orthogonality where the brace is located directly below the non-installed frame structure The seismic reinforcement structure for a viaduct according to claim 1, wherein the vicinity of the joint with the foundation beam is a steel sheet pile non-installation region, and the steel sheet pile is installed only in the steel sheet pile installation region. 2. The viaduct earthquake-proof reinforcement structure according to claim 1, wherein the steel sheet pile is embedded in the ground at a side of the orthogonal foundation beam and a head portion of the steel sheet pile is joined to the orthogonal foundation beam. The viaduct earthquake-proof reinforcement structure according to claim 1, wherein a reinforced concrete floor board is constructed in a rectangular planar space surrounded by the foundation beam and the orthogonal foundation beam, and the reinforced concrete floor board is fastened to the foundation beam and the orthogonal foundation beam. The seismic reinforcement structure of a viaduct according to any one of claims 1 to 4, wherein the brace is a damper brace.

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