JP6660650B2 - Bridge substructure - Google Patents

Description

  The present invention relates to a lower structure of a bridge used for roads, railways, and the like.

  As bridges on which transportation vehicles such as railroads and automobiles travel, there are so-called viaducts that are continuously constructed in urban areas, in addition to narrow bridges that cross rivers and straits. From the viewpoint of efficient land use, such viaducts are continuously constructed in the space on roads, railways, or rivers. It also contributes to eliminating traffic jams.

  When constructing the viaducts described above, the lower structure is often constructed with a reinforced concrete rigid frame.At this time, in order to ensure sufficient earthquake resistance, vibration control consisting of various types of dampers and braces is used. Several configurations in which a mechanism is incorporated into a ramen frame have been proposed (Patent Documents 1 to 3).

JP 2004-270816 A JP 2005-188240 A JP 2003-64620 A

  However, in the configurations of Patent Literatures 1 and 2 described above, the damper mechanism 13 and the brace mechanism 14 occupy the inner space of the rigid frame 3, and in the configuration of Patent Literature 3, the brace-type damper 4 includes the piers 1 and 1 and the beams 2. Occupies the inner space of the beam-and-column frame, which has a problem that the inner space cannot be effectively used as a road or a railway.

  Under such circumstances, the present applicant has studied a configuration in which a friction damper with excellent maintainability is arranged in a cheek stick shape at the corners of the above-described ramen frame or column-beam frame. The frictional material pressed against the sliding material exerts a damping force by sliding on the sliding material, so that the movement of the frictional material along the sliding surface is hindered, or the frictional material slides from the frictional material by the disc spring. It is necessary to avoid situations where the pressing force on the material fluctuates.

  However, in the above-described configuration, when the rigid frame or the beam-column frame vibrates during an earthquake, a bending moment is input to both ends of the friction damper in response thereto, and as a result, the member on which the sliding material is attached or the friction material is attached. The bent member bends to prevent the smooth sliding operation of the friction material along the sliding surface, and the pressing force of the disc spring fluctuates, causing a problem that the function of the friction damper is reduced. .

  By the way, if the both ends of the friction damper are joined to the ramen frame or the beam-column frame via clevis, the above situation can be avoided.However, if mechanical parts like clevis are used, the material cost will be reduced. This may offset the benefits of reduced maintenance burden.

  The present invention has been made in view of the above circumstances, and provides a lower structure of a bridge capable of maintaining the function of a friction damper without impairing economy when incorporating the friction damper into a vibration damping mechanism. Aim.

In order to achieve the above object, a lower structure of a bridge according to the present invention is, as described in claim 1, a column composed of a pair of columns erected so as to face each other and a beam bridged over their tops. In the substructure of a bridge with a beam frame,
A friction damper is obliquely arranged in a cheek cane shape at a portion where the column and the beam are in an inner space surrounded by the pair of columns and the beams, and each end of the friction damper is connected via a plastic hinge mechanism. It is joined to the column and the beam, respectively ,
The plastic hinge mechanism is configured by using a steel plate arranged so as to cause out-of-plane bending around an axis perpendicular to the construction surface of the column-beam frame, and at a portion where the column and the beam meet, When a relative angle is generated between them, the bending moment input to both ends of the friction damper is deformed by bending around an axis perpendicular to the plane of the beam-column structure, and the bending moment of the plastic hinge mechanism is out of plane. It is designed not to exceed the yield value .

Further, the lower structure of the bridge according to the present invention is provided with a pair of pillars erected so as to oppose each other and a beam-to-column frame composed of beams bridged on tops thereof , as described in claim 2. In the substructure of the bridge
A damper mounting portion is arranged to protrude from a beam end of the beam or as a projecting portion of the beam so as to extend substantially parallel to the structure surface of the beam-and-column frame and to the outside of the beam-and-column frame. A friction damper is obliquely arranged in a cheek stick shape at a site where the damper attachment portion is engaged, and each end of the friction damper is joined to the pillar and the damper attachment portion via a plastic hinge mechanism ,
The plastic hinge mechanism is configured by using a steel plate arranged so as to generate out-of-plane bending around an axis perpendicular to the structure surface of the column-beam frame, and a portion where the column and the damper mounting portion are engaged with each other. When a relative angle is generated between them, the bending moment input to both ends of the friction damper is deformed by bending around an axis perpendicular to the construction surface of the column-beam frame, and the bending moment is applied to the surface of the plastic hinge mechanism. It is designed not to be larger than the outer bending yield value .

  In the lower structure of a bridge according to the present invention, the present invention is applied to a lower structure of a bridge provided with a pair of pillars erected so as to face each other and a beam-and-column structure spanning the tops thereof. However, in the first invention, a friction damper is obliquely arranged in a cheek-claw shape in an inner space surrounded by a pair of pillars and a beam and where the pillar and the beam meet, and each end of the friction damper is made of plastic. In the second invention, the damper mounting portion is attached to the beam end of the beam so as to extend substantially parallel to the construction surface of the beam-to-column structure and to extend outside the beam-to-column structure. A friction damper is arranged obliquely in a cheek stick shape at a position where the column and the damper mounting portion meet, and each end of the friction damper is connected to the column and the damper via a plastic hinge mechanism. At the mounting part They are joined.

  In this way, even when the relative angle between the column and the beam or the column and the damper mounting portion changes greatly due to the deformation of the column-and-beam frame during an earthquake, the plastic hinge mechanism allows the structure of the column-and-beam frame to change. The bending moment is larger than the out-of-plane bending yield value of the plastic hinge mechanism and is not input to both ends of the friction damper.

  Therefore, if a friction damper is manufactured so that the function of the above-described plastic hinge mechanism with respect to the out-of-plane bending yield value is not impaired, the movement of the friction material along the sliding surface is prevented, and Therefore, it is possible to prevent a situation in which the pressing force from the friction material to the sliding material fluctuates.

  In a column-beam frame, a friction damper, which is obliquely arranged in a cane shape between a column and a beam or between a column and a damper mounting portion, causes an earthquake along an axis (hereinafter simply referred to as a material axis) from one end to the other end. If it expands and contracts occasionally, the connection state of the column and the beam is arbitrary, not only when it can be considered as pin connection or pin connection, but also when it can be considered as rigid connection or rigid connection, The case where the above-mentioned expansion and contraction operation is realized by shear deformation is also included. That is, in the column-beam frame of the present invention, a frame structure is not excluded, and a structural type such as reinforced concrete (RC), SRC, or S is arbitrary.

  Here, the bridge to which the present invention is applied, when viewed from the bridge axis direction, in other words, it is sufficient that the beam-column frame in the cross section is the above-described beam-column frame, and from the direction orthogonal to the bridge axis. When viewed, in other words, how the frame type in the vertical section is configured is arbitrary.

  In other words, the bridge according to the present invention includes a case in which the frame type when viewed from the bridge axis direction and the frame type when viewed from the bridge axis orthogonal direction are both rigid frame structures (called a viaduct in the field of railway civil engineering). When the frame type when viewed from the bridge axis direction is a ramen frame, and when the frame type when viewed from the bridge axis orthogonal direction is a girder system, that is, when the bridge girder is mounted on a ramen frame that is spaced apart along the bridge axis direction. The case of passing (called a bridge in the field of railway civil engineering) is included.

  The damper mounting portion is disposed substantially parallel to the beam-to-column structure so that the component that vibrates in parallel with the structure of the beam-to-column structure is efficiently suppressed, and the internal space of the beam-to-column frame can be effectively used, What is necessary is just to arrange | position so that it may extend outside a column-beam frame, but the structure arrange | positioned horizontally is a typical example.

Plastic hinge mechanism as long as the restoring force characteristics without increasing bending moment also becomes large curvature in the range beyond the yield point, but may be employed any configuration, in the present invention, beam-column It shall be constituted using a steel plate arranged so as to generate out-of-plane bending around an axis perpendicular to the construction surface of the frame . With this configuration , the plastic hinge mechanism can be configured relatively easily and easily.

FIG. 2 is a front view of a lower structure 1 of the bridge according to the embodiment. FIG. 4 is a longitudinal sectional view of the friction damper 7. FIG. 3 is a perspective view of a plastic hinge mechanism 6. It is a side view of the plastic hinge mechanism 6, (a) is a figure of the plastic hinge mechanism 6 in the state attached to the column 3, (b) is a state in which the H-shaped steel 21a of the friction damper 7 is connected to the plastic hinge mechanism. FIG. Explanatory drawing which showed the effect | action of the lower structure 1 of the bridge which concerns on this embodiment. Explanatory drawing which showed the effect | action of the lower structure 1 of the bridge which concerns on this embodiment similarly. The figure which showed the modification of the lower structure 1 of the bridge which concerns on this embodiment. Explanatory drawing which showed the effect | action of the lower structure of the bridge which concerns on a modification.

  Hereinafter, an embodiment of a bridge substructure according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a front view of a lower structure of a bridge according to the present embodiment as viewed from a bridge axis direction. As shown in the figure, the lower structure 1 of the bridge according to the present embodiment has pillars 3 erected so as to face the footings 2, 2, respectively, and a beam 4 is provided on top of the pair of pillars 3, 3. And the pillars 3 and 3 and the beam 4 constitute a ramen frame 5 as a column-beam frame. The ramen frame 5 can be made of reinforced concrete (RC).

  A friction damper 7 is obliquely arranged in a cheek stick shape at each of the inner corners surrounded by the pair of pillars 3 and 3 and the beam 4 where the pillar 3 and the beam 4 meet. Are joined to the column 3 and the beam 4 via the plastic hinge mechanism 6, respectively.

  As shown in FIG. 2, the friction damper 7 includes H-shaped steel members 21a and 21b joined to the columns 3 and the beams 4 via the plastic hinge mechanism 6, respectively. And a long sliding member 24 is fixed to both surfaces of the web 22a along the groove, and brackets 25, 25 are attached to both surfaces of the web 22b of the H-section steel 21b. A friction member 26 abutting on the sliding member 24 is attached to the opposing inner surface of the bracket, and a web 22a having the sliding member 24 fixed on both surfaces is attached to the friction member 26 abutting on the sliding member. , 25 so as to be sandwiched by each other and share the same material axis, the two H-shaped steels 21 a and 21 b are arranged relative to each other, and are inserted through the slot 23 so that the other H-shaped steel 21 a and 21 b Friction material 6 and a bracket 25, a rod 27 is inserted through the plate, a disc spring 28 is attached to each end of the rod, and this is tightened with a nut 29. Input is made from the column 3 and the beam 4 via the plastic hinge mechanism 6. The damping force due to friction is exerted in response to the relative speed in the axial direction of the material.

  As shown in FIGS. 3 and 4, the plastic hinge mechanism 6 includes a frame-side mounting portion 31 joined to the column 3, a plastic hinge body 32 extending from the frame-side mounting portion, and a damper-side mounting portion 33 extending from the plastic hinge body. It consists of

  The frame-side mounting portion 31 is formed by erecting triangular stiffening plates 35, 35 from respective longitudinal edges of a substrate 34, the back surface of which is in contact with the side surface of the column 3. And a strip-shaped steel plate 36 is formed so as to be welded to the front of the substrate 34 and to extend obliquely to the substrate 34.

  Further, rectangular steel plates 37, 37 are disposed opposite to each other in the orthogonal direction at the front end of the strip-shaped steel plate 36. The front end of each of the rectangular steel plate and the strip-shaped steel plate 36 is formed by connecting the front end of the strip-shaped steel plate 36 with a web, , 37 constitute a H-shaped steel damper-side mounting portion 33.

  As described above, the strip-shaped steel plate 36 constitutes a part of the frame-side attachment part 31 on the base end side and a part of the damper-side attachment part 33 on the distal end side, and has a width δ sandwiched therebetween (see FIG. 4). The middle portion of the plastic hinge is in a range where the stiffening by the stiffening plates 35, 35 and the rectangular steel plates 37, 37 does not reach, and the out-of-plane bending deformation is likely to occur. It functions as the main body 32.

  The damper-side mounting portion 33 is configured such that the width of the rectangular steel plate 37 matches the flange width of the H-shaped steel 21a, and the width of the belt-shaped steel plate 36 matches the height of the web 22a of the H-shaped steel 21a. When the section steels 21a are butt-arranged, they can be connected to the H section steels using the flange plates 38a, 38b and the web plate 39.

  Note that the plastic hinge mechanism 6 is also installed on the beam 4 side, but it is sufficient to replace the above-mentioned column 3 with the beam 4, so that the description thereof is omitted here.

  When the plastic hinge mechanism 6 is installed on the column 3 or the beam 4, it is desirable that the column 3 or the beam 4 be rolled up with a steel plate and fixed to the steel plate by welding or the like.

  In the lower structure 1 of the bridge according to the present embodiment, the friction dampers 7 are obliquely arranged in a cheek-claw-like manner in a portion where the pillars 3 and the beams 4 meet in the inner space surrounded by the pair of columns 3 and 3 and the beams 4. At the same time, each end of the friction damper is connected to the column 3 and the beam 4 via the plastic hinge mechanism 6, respectively.

  In this way, as shown in FIG. 5, in the event of an earthquake, the distance between both ends of the friction damper 7 alternately expands and contracts in such a manner that the left side extends and the right side contracts in accordance with the deformation of the rigid frame 5. As a result, the friction damper exerts a damping force.

  Also, as shown in FIG. 6, even if the relative angle φ between the column 3 and the beam 4 changes significantly due to the deformation of the rigid frame 5 during an earthquake, the plastic hinge main body 32 bends and deforms in an out-of-plane direction, that is, The bending moment is input to both ends of the friction damper 7 because the bending moment is larger than the out-of-plane bending yield value of the plastic hinge main body 32 because the bending is performed around the axis perpendicular to the plane of the frame 5 and around the axis perpendicular to the plane of FIG. There is no fear.

  As described above, according to the bridge lower structure 1 according to the present embodiment, each end of the friction damper 7 is joined to the column 3 and the beam 4 via the plastic hinge mechanism 6, respectively. 7 is manufactured so that the function thereof is not impaired with respect to the out-of-plane bending yield value of the plastic hinge mechanism 6, so that the movement of the friction material 26 along the sliding surface is prevented or the disc spring 28 Therefore, it is possible to prevent a situation in which the pressing force from the friction material 26 to the sliding material 24 fluctuates.

  In addition, according to the bridge lower structure 1 according to the present embodiment, the friction damper 7 is formed in a cheek stick shape in an inner space surrounded by the pair of columns 3 and 3 and the beam 4 and where the column 3 and the beam 4 meet. The rails and roads are laid in the internal space 31 of the ramen frame 5, so that the internal space can be effectively used.

  In the present embodiment, the frame frame 5 is adopted as the column-beam frame. However, instead of this, a frame in which the top of the column 3 and the beam 4 are joined by pins may be adopted.

  Further, in the present embodiment, the friction damper 7 is arranged in a portion where the column 3 and the beam 4 meet each other in the inner space surrounded by the pair of columns 3 and 3 and the beam 4. As shown in (1), overhanging portions 71, 71 as damper attachment portions are provided on the beam 4b bridged over the pillars 3, 3 as a part of the beam 4b, and friction is applied to a portion where each overhanging portion and the pillar 3 join. It is possible to adopt a configuration in which the dampers 7 are each arranged obliquely in a cheek stick shape.

  The overhang portions 71, 71 extend from the outer side surfaces of the pillars 3, 3 so as to extend substantially parallel to the outer surface of the ramen frame 5b as a column-beam frame composed of the columns 3, 3, and the beams 4b and to the outside of the ramen frame. What is necessary is just to make each project.

  Each end of the friction damper 7 is joined to the column 3 and the lower surface of the overhang portion 71 via the plastic hinge mechanism 6.

  Also in this modified example, as shown in FIG. 8, at the time of the earthquake, the distance between both ends of the friction damper 7 is alternately changed in such a manner that the right side is extended and the left side is contracted in accordance with the deformation of the rigid frame 5b. The friction damper exerts a damping force by expansion and contraction.

  Also, as described with reference to FIG. 6, even if the relative angle φ between the column 3 and the overhang portion 71 greatly changes due to the deformation of the rigid frame 5b during an earthquake, the plastic hinge main body 32 bends and deforms in the out-of-plane direction. In other words, since bending deformation occurs around an axis perpendicular to the plane of the frame structure 5b, and in this figure, around an axis perpendicular to the plane of the drawing, a bending moment greater than the out-of-plane bending yield value of the plastic hinge body 32 is applied to both ends of the friction damper 7. There is no risk of input.

  Hereinafter, this modified example has substantially the same configuration as that of the above-described embodiment except that the joining target is not the beam 4 but the overhang portion 71, and the operation and effect are also the same. Omitted.

  In the above-described modified example, the damper attachment portion is configured as the overhang portion 71 that is a part of the beam 4b, but instead, a damper attachment member (not shown) having the same shape as the overhang portion 71 is provided. It may be configured to protrude from the material end of the beam 4.

  Although not particularly mentioned in the present embodiment, a configuration in which a coating by application, adhesion, or the like is formed on the sliding surface of the sliding member 24 may be adopted.

  The coating is formed so as not to hinder the sliding operation of the friction material 26, and it is desirable that the coating be as excellent as possible in weather resistance.

  According to this modification, when the friction damper 7 operates during an earthquake, the coating of the sliding material 24 peels over the sliding range of the friction material 26. By observing the state of the peeling, the maximum of the friction damper 7 can be obtained. The displacement can be easily grasped, and thus the above-described configuration can function as a peak sensor.

  Also, unlike the conventional peak sensor, no maintenance is required, so that the configuration is optimal as a peak sensor applied to a bridge or the like.

  It should be noted that it is sufficient to observe only one of the friction dampers 7, 7 arranged on the left and right, which is easy to observe, but it is sufficient to observe both according to the situation. It doesn't matter.

1 Lower structure of bridge 3 Pillar 4, 4b Beam 5, 5b Ramen frame
6 Plastic hinge mechanism 7 Friction damper 32 Plastic hinge body (steel plate)
71 Overhanging part (damper mounting part)

Claims (2)

In a lower structure of a bridge provided with a pair of columns erected to face each other and a beam-to-column frame composed of beams spanned on the tops thereof,
A friction damper is obliquely arranged in a cheek cane shape at a site where the column and the beam meet in the inner space surrounded by the pair of columns and the beams, and each end of the friction damper is connected via a plastic hinge mechanism. It is joined to the column and the beam, respectively ,
The plastic hinge mechanism is configured by using a steel plate arranged so as to cause out-of-plane bending around an axis perpendicular to the construction surface of the column-beam frame, and at a portion where the column and the beam meet, When a relative angle is generated between them, the bending moment input to both ends of the friction damper is deformed by bending around an axis perpendicular to the plane of the beam-column structure, and the bending moment of the plastic hinge mechanism is out of plane. Substructure of a bridge characterized by not being greater than the yield value . In a lower structure of a bridge provided with a pair of columns erected to face each other and a beam-to-column frame composed of beams spanned on the tops thereof,
A damper mounting portion is arranged to protrude from a beam end of the beam or as a projecting portion of the beam so as to extend substantially parallel to the structure surface of the beam-and-column frame and to the outside of the beam-and-column frame. A friction damper is obliquely arranged in a cheek stick shape at a site where the damper attachment portion is engaged, and each end of the friction damper is joined to the pillar and the damper attachment portion via a plastic hinge mechanism ,
The plastic hinge mechanism is configured by using a steel plate arranged so as to generate out-of-plane bending around an axis perpendicular to the structure surface of the column-beam frame, and a portion where the column and the damper mounting portion are engaged with each other. When a relative angle is generated between them, the bending moment input to both ends of the friction damper is deformed by bending around an axis perpendicular to the construction surface of the column-beam frame, and the bending moment is applied to the surface of the plastic hinge mechanism. A substructure of a bridge, characterized in that it does not become larger than an outside bending yield value .

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