JP2017110345A - Understructure of bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively use as much as possible an internal space of a post beam bridge frame.SOLUTION: In an understructure 1 of a bridge according to the present invention, posts 3 are respectively raised so as to mutually face footings 2, 2, and a beam 4 is bridged on a top part of the pair of posts 3, 3, thus, the posts 3, 3 and the beam 4 constitute a rahmen bridge frame 5 as a post beam bridge frame. The beam 4 is provided with protrusion parts 6, 6 as a damper fitting part in such a manner as being parallel to a frame surface of the rahmen bridge frame 5 and extending toward the outside of the rahmen bridge frame, and between the protrusion part 6 and the post 3, the friction damper 7 is diagonally arranged respectively for bracing support. The protrusion part 6 may be configured as a part of the beam 4 that protrudes from an outer side surface of the post 3.SELECTED DRAWING: Figure 1

Description

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

  Bridges on which transport vehicles such as railways and automobiles travel include so-called viaducts that are continuously constructed in urban areas, in addition to narrow bridges that cross rivers and straits. Such a viaduct is constructed continuously in space on roads, railroads, or rivers from the viewpoint of efficient land use, and roads or railroads under the viaduct cross three-dimensionally. Contributes to eliminating traffic jams.

  In constructing the above-mentioned viaduct, the substructure is often constructed with a reinforced concrete rigid frame, but at that time, it must be designed and constructed so as to ensure sufficient earthquake resistance.

JP 2004-270816 A JP 2005-188240 A JP-A-11-323826

  Under such circumstances, the present applicant, as shown in Patent Documents 1 and 2, has a viaduct substructure 12 in which a damper mechanism 13 and a brace mechanism 14 are arranged in a reinforced concrete rigid frame 3 composed of columns 1 and 1 and a beam 2. According to this configuration, it is possible to significantly improve the earthquake resistance.

  However, in the above-described viaduct substructure 12, the damper mechanism 13 and the brace mechanism 14 occupy the inner space of the ramen frame 3, which causes a problem that the inner space cannot be effectively used as a road or a railway. .

  Incidentally, in Patent Document 3, a ramen structure 13 is constituted by a pair of columnar piers 11, 11 facing each other and a beam 12 laid over the top of the columnar pier, and the apex is formed inside the ramen structure. There is disclosed a configuration in which a brace material 14 having an inverted V shape is disposed so as to be joined in the vicinity of the center of the beam 12 and to be joined to the intermediate height positions of the pair of columnar piers 11 and 11 respectively. In the configuration, only the upper part of the inner space of the ramen structure 13 is occupied by the brace material 14, so that the inner space can be used effectively to some extent, but there may be a case where the earthquake resistance cannot be secured with a margin. .

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a bridge lower structure that can effectively use the internal space of the column beam frame as much as possible while ensuring sufficient earthquake resistance. .

In order to achieve the above-mentioned object, the bridge lower structure according to the present invention is, as described in claim 1, a pair of columns erected so as to face each other and a column spanned between the tops of the columns. In the substructure of a bridge with a beam frame,
The damper mounting portion is arranged so as to protrude from the material end of the beam so as to extend substantially parallel to the surface of the column beam frame and to the outside of the column beam frame, or as a protruding portion of the beam, and the damper, One end thereof is disposed at an angle between the damper mounting portion and the column in a state in which the other end is joined to the damper mounting portion and the other end is bonded to a side surface of the column located below the damper mounting portion.

  In the bridge lower structure according to the present invention, the damper is a friction damper.

  In the bridge lower structure according to the present invention, the damper mounting portion is made of a steel material.

  In the bridge lower structure according to the present invention, the damper mounting portion is an overhang portion of the beam, and the beam is made of prestressed concrete.

  In the lower structure of the bridge according to the present invention, the present invention is applied to the lower structure of the bridge provided with a column beam structure including a pair of columns erected so as to be opposed to each other and beams bridged on top of them. However, at that time, the damper mounting portion is arranged to protrude from the material end of the beam so as to extend substantially parallel to the surface of the column beam frame and to the outside of the column beam frame, or as a protruding portion of the beam, The damper is obliquely disposed between the damper mounting portion and the column in a state where one end is joined to the damper mounting portion and the other end is joined to the side surface of the column located below the damper mounting portion.

  In this way, in the event of an earthquake, as the column beam frame is deformed, the distance between the ends of the damper expands and contracts, and the damper exerts a damping force. It is possible to control the beam frame.

  A column beam frame can be used when a damper that is diagonally arranged like a cane between the damper mounting part and the column expands and contracts during an earthquake along an axis (hereinafter simply referred to as a material axis) from one end to the other end. The column-beam connection state is arbitrary, and it can be regarded as a pin connection or pin connection, and even if it can be regarded as a rigid connection or a rigid connection, the expansion and contraction described above is caused by the bending deformation or shear deformation of the column. It is also included when the action is realized. That is, the column beam frame of the present invention does not exclude the frame structure, and the structure types such as reinforced concrete (RC), SRC, and S are also arbitrary.

  Here, when the bridge to which the present invention is applied is viewed from the direction of the bridge axis, in other words, the column beam frame in the cross section is sufficient if it is the above-mentioned column beam frame. When viewed, in other words, how the frame form in the longitudinal section is configured is arbitrary.

  In other words, the bridge according to the present invention includes a case where the frame type when viewed from the bridge axis direction and the direction orthogonal to the bridge axis is a ramen frame (referred to as a viaduct in the field of railway civil engineering). If the frame type when viewed from the bridge axis direction is a ramen frame, and the frame type when viewed from the direction orthogonal to the bridge axis is a girder type, that is, the bridge girder is mounted on a ramen frame 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 may be any damper as long as the damping force is exhibited by the relative speed generated along the material axis, and can be constituted by a friction damper, a viscoelastic damper, a viscous damper, or the like.

  The damper mounting part is arranged almost parallel to the structural surface so that the component that vibrates in parallel to the structural surface in the column beam frame is efficiently suppressed, and the internal space of the column beam frame can be used effectively. Although it should just arrange | position so that it may extend outside a column beam frame, the structure arrange | positioned horizontally becomes a typical example.

  It is arbitrary what kind of material the damper mounting part is made of, but if it is made of steel or prestressed concrete, when a tensile load acts on the damper mounting part as a reaction force when the damper contracts, the tensile load Can be reliably supported.

The front view of the lower structure 1 of the bridge which concerns on this embodiment. FIG. 3 is a longitudinal sectional view of the friction damper 7. Explanatory drawing which showed the effect | action of the lower structure 1 of the bridge which concerns on this embodiment. The figure which showed the modification of the lower structure 1 of the bridge which concerns on this embodiment. The figure which showed another modification of the lower structure 1 of the bridge which concerns on this embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a bridge lower structure 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 the bridge axis direction. As shown in the figure, in the bridge lower structure 1 according to the present embodiment, the pillars 3 are erected so as to face the footings 2 and 2, respectively, and the beams 4 are formed on the tops of the pair of pillars 3 and 3. The columns 3 and 3 and the beam 4 constitute a frame frame 5 as a column beam frame. The ramen frame 5 can be a reinforced concrete structure (RC structure).

  The beam 4 is provided with overhang portions 6 and 6 as damper attachment portions so as to extend parallel to the surface of the ramen frame 5 and to the outside of the ramen frame, and between the overhang portion 6 and the column 3. The friction dampers 7 are arranged obliquely in a cheek-like shape. What is necessary is just to comprise the overhang | projection part 6 as a part of beam 4 so that it may protrude from the outer side surface of the pillar 3. FIG.

  The friction damper 7 has one end joined to the lower surface of the overhang portion 6 and the other end joined to the outer side surface of the column 3 positioned below the overhang portion by pin bonding. A damping force due to friction is exhibited in response to the input relative speed in the axial direction.

  As shown in FIG. 2, the friction damper 7 forms a slot 23 along the axis of the web 22a of the H-shaped steel 21a connected to the column 3 by pin bonding, and the web 22a is formed along the slot. While the long sliding member 24 is fixed to both surfaces, brackets 25 and 25 are attached to both surfaces of the web 22b of the H-section steel 21b connected to the overhanging portion 6 by pin bonding, and slides on the opposing inner surface of the bracket. Friction material 26 that is in contact with material 24 is attached to each other, and web 22a having sliding material 24 fixed on both sides is sandwiched between brackets 25 and 25 to which friction material 26 that is in contact with the sliding material is attached. The two H-shaped steels 21a and 21b are arranged relative to each other so as to share the shaft, and are then inserted from the one bracket 25 and the friction material 26 into the other friction material 26 and the bracket 25 while being inserted into the slot 23. The head 27 through disposed to the disc spring 28 attached to each end of the rod, there it as a tightening nut 29.

  In the bridge lower structure 1 according to the present embodiment, the projecting portions 6 and 6 are provided on the beam 4 so as to extend substantially parallel to the surface of the rigid frame 5 and to the outside of the rigid frame 5, and the projecting portion 6 has one end. However, the friction damper 7 is diagonally arranged like a cheek can so that the other end is joined to the side surface of the column 3 positioned below the overhanging portion.

  In this case, as shown in FIG. 3, in the event of an earthquake, the distance between both ends of the friction damper 7 is alternately expanded and contracted in such a manner that the right side in FIG. Thus, the friction damper exhibits a damping force.

  As described above, according to the bridge lower structure 1 according to the present embodiment, the ramen frame can be damped without disposing dampers or braces in the internal space 31 of the ramen frame 5.

  Therefore, the internal space can be effectively used to the maximum extent, for example, a railroad or a road is laid in the internal space 31 of the frame frame 5.

  In this embodiment, the friction damper 7 is used as the damper. However, the damper of the present invention is not limited to the friction damper 7, and a viscoelastic damper or a viscous damper can be used instead of the friction damper. is there.

  In the present embodiment, the ramen frame 5 is adopted as the column beam frame. However, as shown in FIG. 4A, a frame in which the top of the column 3 and the beam 4 are pin-joined may be used.

  Moreover, in this embodiment, it was set as the structure which does not arrange | position any damping mechanism, such as a damper and a brace, in the internal space 31 of the frame frame 5, but if only the friction damper 7 is insufficient in the earthquake resistance of the whole frame, For example, a damper brace mechanism 41 may be disposed in the internal space 31 as shown in FIG.

  The damper brace mechanism 41 is composed of a hysteresis damping type damper 42 suspended from the lower surface of the beam 4 and two brace members 43 and 43 having upper ends connected to the hysteresis damping type damper by pin joints. The lower end of the brace material 43 is connected to the column by pin bonding in the vicinity of the intermediate height of the column 3.

  In such a modification, it is difficult to make maximum use of the internal space 31 surrounded by the columns 3, 3 and the beam 4, but the vibration control action by the friction damper 7 should be installed in the internal space 31. The degree of occupation of the vibration mechanism can be kept to a minimum, and there is no difference from the above-described embodiment in that the effective use inside the frame is improved.

  Further, in this embodiment, the damper mounting portion is configured by the overhang portion 6 which is a part of the beam 4, but instead, the outer dimension of the columns 3 and 3 is set to the member length as shown in FIG. Damper mounting members 51 and 51 may be provided in a form protruding from the end of the beam 4b, and this may be used as the damper mounting portion of the present invention.

  Although not particularly mentioned in the present embodiment, in the event of an earthquake, when the friction damper 7 contracts, as a reaction force, a tensile load acts on the left overhanging portion 6 in FIG.

  In such a case, it is possible to cope by increasing the amount of reinforcing bars of the overhanging portion 6 or enlarging the cross section, but this impairs the economics of the overhanging portion 6 and further imposes a burden on the pillar 3 and the footing 2. If there is a concern of increasing the size, the overhang portion 6 may be made of steel instead of reinforced concrete. It is optional whether the entire beam 4 is made of steel or only the damper mounting member 51 is made of steel as shown in FIG.

  Moreover, when the same situation is concerned, the beam 4 may be made of prestressed concrete.

  According to each modification mentioned above, it becomes possible to support the said tensile load reliably, without impairing economical efficiency.

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

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

  According to such a modified example, when the friction damper 7 is actuated during an earthquake, the coating of the sliding material 24 is peeled over the sliding range of the friction material 26. By observing the peeling state, the maximum of the friction damper 7 is observed. The displacement can be easily grasped, and thus the above-described configuration can be functioned as a peak sensor.

  In addition, unlike conventional peak sensors, since maintenance is not required, the peak sensor applied to a bridge or the like is optimal.

  In addition, as for the peeling state of the coating provided on the sliding member 24, it is sufficient to observe only the easier to observe among the friction dampers 7 and 7 arranged on the left and right sides, but both are observed according to the situation. It doesn't matter.

1 Bridge substructure 3 Column 4 Beam 5 Ramen frame (column beam frame)
6 Overhang part (damper mounting part)
7 Friction damper (damper)

Claims (4)

In the lower structure of the bridge provided with a column beam structure composed of a pair of columns erected so as to face each other and beams spanned on top of them,
The damper mounting portion is arranged so as to protrude from the material end of the beam so as to extend substantially parallel to the surface of the column beam frame and to the outside of the column beam frame, or as a protruding portion of the beam, and the damper, It is characterized in that one end thereof is disposed at an angle between the damper mounting portion and the column in a state in which the other end is joined to the damper mounting portion and the other end is joined to a side surface of the column located below the damper mounting portion. The substructure of the bridge. The bridge lower structure according to claim 1, wherein the damper is a friction damper. The bridge lower structure according to claim 1 or 2, wherein the damper mounting portion is made of steel. The bridge lower structure according to claim 1 or 2, wherein the damper mounting portion is an overhang portion of the beam, and the beam is made of prestressed concrete.

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