JP4943190B2 - 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. A first foundation structure in which a rigid frame supporting the superstructure of the viaduct is erected, and the foundation beam and the orthogonality are connected to each other in a rectangular shape or a ladder shape. The steel sheet pile embedded in the ground along the periphery of the rectangular planar space surrounded by the foundation beam and the head portion of the steel sheet pile are joined and disconnected from the first foundation structure. A second basic structure composed of a reinforced concrete floor plate constructed in a rectangular planar space, and a plurality of brace bodies are arranged in an inverted polygonal pyramid directly above the rectangular planar space, and the upper ends thereof constitute the frame structure Out of pillars The bonded to the head near the pillars surrounding the rectangular flat space is obtained a three-dimensional brace formed by joining their lower near the center of the reinforced concrete floor.

  Moreover, the seismic reinforcement structure of the viaduct according to the present invention is such that the three-dimensional brace is a three-dimensional damper brace by interposing dampers between the plurality of brace bodies and the reinforced concrete floor board.

  The present invention is intended for seismic reinforcement of a substructure of a viaduct composed of a ramen frame that is an above-ground part and a base structure (first basic structure) of an underground part in which the ramen frame is erected. The foundation structure of 1 includes 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 in a rectangular shape or a ladder shape. Configured.

  And in this invention, while embedding the steel sheet pile also called a sheet pile along the periphery of the rectangular planar space surrounded by the foundation beam and the orthogonal foundation beam described above, the head of the steel sheet pile is joined. The reinforced concrete floor board is newly constructed in the rectangular planar space so as to be disconnected from the first foundation structure, and this is used as the second foundation structure, and the columns surrounding the rectangular planar space are A plurality of brace bodies are joined in the vicinity of the head, and the lower ends thereof are joined in the vicinity of the center of the reinforced concrete floor board to construct a three-dimensional brace.

  In this way, the horizontal force during an earthquake flowing to the first foundation structure, which is the existing foundation structure via the ramen frame, is partially added to the second foundation structure after the seismic reinforcement. As a result, it is possible to cause the horizontal force during an earthquake from the viaduct superstructure to be newly borne not only on the first foundation structure but also on the second foundation structure. Combined with the seismic reinforcement of the ground part by the above, it becomes possible to seismically strengthen the substructure of the viaduct overall.

  In addition, the pull-out force and compressive force at the time of an earthquake caused by rocking vibration of the entire frame structure along the direction orthogonal to the bridge axis are the same as the horizontal force described above, and some of them are second through the three-dimensional brace. Flows into the foundation structure. And these drawing-out force or compressive force is supported by the frictional force of the steel sheet pile and the surrounding ground, especially the frictional force of the steel sheet pile arranged along the foundation beam and the surrounding ground.

  The three-dimensional brace means that three or more brace bodies are not arranged on the same surface, in other words, a brace formed by arranging three or more brace bodies on two different surfaces that are not parallel to each other. In the case of a book, the inverted polygonal pyramid is an inverted quadrangular pyramid. Furthermore, when the rectangular planar space is square and the lower end of the brace body is joined to the center of the reinforced concrete floor board, the shape of the solid brace is a shape in which the regular quadrangular pyramid is turned upside down.

  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 brace in a narrow sense.

  The steel sheet piles do not necessarily have to be arranged all around along the periphery of the rectangular plane space, but they can be opposed if they support the pulling force and compressive force caused by the rocking vibration of the rigid frame along the direction perpendicular to the bridge axis. It is effective to embed them in the ground inside the pair of foundation beams. On the other hand, if the horizontal seismic force in the direction perpendicular to the bridge axis is to be supported, it is effective to embed each in the ground inside a pair of opposed orthogonal foundation beams.

  The steel sheet piles may be in contact with the foundation beam or the orthogonal foundation beam constituting the first foundation structure, but are structurally disconnected from each other. With such a configuration, it is possible to improve the efficiency of construction, and the interaction with the first foundation structure and the frame structure erected on the first foundation structure is reduced, and the design is facilitated.

  As long as the pulling force and compressive force transmitted from the three-dimensional brace can be transmitted to the steel sheet pile, any structure can be adopted as the joining structure of the steel sheet pile and the reinforced concrete floor board. Bonding is also acceptable.

  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.

  1 to 3 are views showing a seismic reinforcing structure of a viaduct according to the present embodiment. As can be seen from these drawings, the viaduct seismic reinforcement structure 1 according to the present embodiment is a ground portion, and is composed of a pair of columns 8 and 8 and a beam 9 spanning the heads of the columns. The substructure 3 of the viaduct composed of the ramen frame 4 and the base structure 5 of the underground portion as the first foundation structure on which the ramen frame is erected is an object of seismic reinforcement. A pair of foundation beams 6 and 6 arranged opposite to each other along the bridge axis direction and a plurality of orthogonal foundation beams 7 arranged so as to be substantially orthogonal to the pair of foundation beams are connected in a ladder shape. is there. The foundation structure 5 is continuously constructed along the direction of the bridge axis, and supports the superstructure 2 of the viaduct via the ramen frame 4 that is the ground part.

  The seismic retrofit structure 1 according to the present embodiment includes a peripheral edge of a rectangular planar space surrounded by the foundation beams 6 and 6 and the orthogonal foundation beams 7 and 7, in other words, the foundation beams 6 and 6 and the orthogonal foundation beams 7 and 7. The steel sheet pile 13 is embedded in the ground 14 in a box shape along the inner side, and the reinforced concrete floor board 62 is constructed in a rectangular planar space so that the head of the steel sheet pile is joined, and the steel sheet pile 13 and the reinforced concrete floor board are formed. 62 forms a foundation structure 63 as a second foundation structure newly added at the time of earthquake-proof reinforcement work.

  Here, the seismic reinforcement structure 1 is configured by arranging a three-dimensional damper brace 71 as a three-dimensional brace directly above a rectangular planar space surrounded by the foundation beams 6 and 6 and the orthogonal foundation beams 7 and 7.

  The three-dimensional damper brace 71 has four brace bodies 72 arranged in an inverted quadrangular pyramid immediately above the rectangular planar space, and surrounds the rectangular planar space among the pillars 8 constituting the rigid frame 4 at the upper ends thereof. The column 8 is joined to the vicinity of the head, and the lower ends thereof are joined to the vicinity of the center of the reinforced concrete floor board 62 through the hysteresis damping damper 73, and are accompanied by the horizontal force and the rocking vibration during the earthquake from the rigid frame 4 A compressive force and a tensile force are transmitted to the foundation structure 63.

  In order to construct the viaduct seismic reinforcement structure 1 according to the present embodiment, first, the steel sheet pile 13 is embedded in the ground 14 in a box shape along the inside of the foundation beams 6 and 6 and the orthogonal foundation beams 7 and 7. 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.

  Next, the ground surrounded by the steel sheet pile 13 is dug down to form a rectangular planar space, and then a reinforced concrete floor board 62 is constructed in the rectangular planar space. At this time, for example, a stud is welded to the head of the steel sheet pile 13 so that the head of the steel sheet pile 13 is joined to the reinforced concrete floor board 62, and a reinforcing bar is arranged in a rectangular plane space where the concrete is placed. In this state, concrete is placed in a rectangular planar space.

  Next, the three-dimensional damper brace 72 is disposed immediately above the reinforced concrete floor board 62.

  In the viaduct seismic reinforcement structure 1 according to the present embodiment, as shown in FIG. 4, the horizontal force acting on the lower structure 3 from the upper structure 2 during the earthquake flows to the existing foundation structure 5, and the three-dimensional damper brace 71 is Then, it flows into the newly added foundation structure 63 in the seismic reinforcement work and is supported by the foundation structure.

  Specifically, the horizontal force transmitted through the three-dimensional damper brace 71 is transmitted to the reinforced concrete floor board 62, and then the friction between the steel sheet pile 13 disposed along the orthogonal foundation beams 7 and 7 and the surrounding ground. While being supported by force, it is supported by a normal direction force (surface pressure) between the steel sheet pile 13 arranged along the foundation beams 6 and 6 and the surrounding ground.

  Further, the pulling force and the compressive force accompanying the rocking vibration of the rigid frame 4 are transmitted to the foundation structure 63 through the three-dimensional damper brace 71, and the steel sheet pile 13 disposed on the side along the foundation beams 6 and 6 and the surrounding ground. It is supported by the frictional force.

  That is, the steel sheet pile 13 arranged on the side along the foundation beams 6 and 6 is in contact with the ground 14 with an area of installation width 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 seismic reinforcement structure 1 of the viaduct according to the present embodiment, the horizontal force at the time of the earthquake flowing to the existing foundation structure 5 via the rigid frame 4 is partially after the seismic reinforcement. , It flows to the added foundation structure 63 through the three-dimensional damper brace 71, and as a result, the horizontal force during an earthquake from the viaduct superstructure 2 is newly borne not only on the existing foundation structure 5 but also on the foundation structure 63 Thus, the underground part of the viaduct substructure can be seismically reinforced.

  Further, according to the viaduct seismic reinforcement structure 1 according to the present embodiment, the pulling force and compressive force resulting from the rocking vibration of the entire frame 4 are supported by the peripheral frictional force between the pile 15 and the surrounding ground. The steel sheet pile 13 arranged along the foundation beams 6 and 6 is supported by the frictional force between the surrounding ground.

  Therefore, in combination with the seismic reinforcement effect of the three-dimensional damper brace 71, the viaduct substructure 3 can be seismically reinforced as a whole.

  In the present embodiment, the three-dimensional damper brace 71 in which the hysteresis damping damper 10 is incorporated is adopted as the brace. However, whether or not the damper is incorporated is optional, and this may be omitted and the brace may be configured by the brace body 72 alone. It doesn't matter. In such a case, the lower end of the brace body 72 is configured to be in rigid contact with the reinforced concrete floor board 62.

The vertical sectional view of the seismic reinforcement structure of a viaduct concerning this embodiment. The horizontal sectional view which follows the AA line. The vertical sectional view which follows a BB line. The figure which showed the effect | action in the earthquake-proof reinforcement structure of the viaduct concerning this embodiment.

Explanation of symbols

1 Seismic reinforcement structure of viaduct 2 Superstructure of viaduct 3 Substructure of viaduct 4 Ramen frame 5 Foundation structure (first foundation structure)
6 foundation beam 7 orthogonal foundation beam 8 pillar 13 steel sheet pile 14 ground 62 reinforced concrete floor board 63 foundation structure (second foundation structure)
71 Solid damper brace (solid brace)
72 Brace body 73 Hysteresis damper

Claims (2)

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 connected in a rectangular shape or a ladder shape, and the upper portion of the viaduct A first foundation structure in which a rigid frame supporting the structure is erected, a steel sheet pile embedded in the ground along a peripheral edge of a rectangular planar space surrounded by the foundation beam and the orthogonal foundation beam, and the steel sheet pile A second foundation structure comprising a reinforced concrete floor plate constructed in the rectangular planar space so that the heads of the two are joined and disconnected from the first foundation structure; and A plurality of brace bodies are arranged in an inverted polygonal pyramid directly above and their upper ends are joined to the vicinity of the heads of the columns surrounding the rectangular planar space among the columns constituting the ramen frame, and their lower ends are connected to the reinforced concrete. Retrofit structure viaduct, characterized in that a three-dimensional brace formed by joining in the vicinity of the center of the plate. The viaduct earthquake-proof reinforcement structure according to claim 1, wherein the three-dimensional brace is a three-dimensional damper brace by interposing a damper between the plurality of brace bodies and the reinforced concrete floor board.

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