U.S. patent application number 14/934827 was filed with the patent office on 2016-08-04 for bridge pier structure.
This patent application is currently assigned to JFE CIVIL ENGINEERING & CONSTRUCTION CORPORATION. The applicant listed for this patent is JFE Civil Engineering & Construction Corporation. Invention is credited to Yasuke IMANO, Hiroyuki IMASHIO, Kazuaki MIYAGAWA, Hitoshi NAITO, Yuya SAKURAI, Keisuke SHIOTA.
Application Number | 20160222608 14/934827 |
Document ID | / |
Family ID | 56555899 |
Filed Date | 2016-08-04 |
United States Patent
Application |
20160222608 |
Kind Code |
A1 |
SHIOTA; Keisuke ; et
al. |
August 4, 2016 |
BRIDGE PIER STRUCTURE
Abstract
A bridge pier structure includes a damper having damping
characteristics, a substructure joined with a lower end portion of
the damper, and a pillar member provided upright on the
substructure, a side surface of the pillar member being joined with
an upper end portion of the damper. The damper is substantially
parallel to the side surface of the pillar member.
Inventors: |
SHIOTA; Keisuke; (Tokyo,
JP) ; MIYAGAWA; Kazuaki; (Tokyo, JP) ;
IMASHIO; Hiroyuki; (Tokyo, JP) ; NAITO; Hitoshi;
(Tokyo, JP) ; SAKURAI; Yuya; (Tokyo, JP) ;
IMANO; Yasuke; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JFE Civil Engineering & Construction Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
JFE CIVIL ENGINEERING &
CONSTRUCTION CORPORATION
Tokyo
JP
|
Family ID: |
56555899 |
Appl. No.: |
14/934827 |
Filed: |
November 6, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E01D 19/02 20130101 |
International
Class: |
E01D 19/02 20060101
E01D019/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 4, 2015 |
JP |
2015-020650 |
Claims
1. A bridge pier structure comprising: a damper having damping
characteristics; a substructure joined with a lower end portion of
the damper; and a pillar member provided upright on the
substructure, a side surface of the pillar member being joined with
an upper end portion of the damper, the damper being substantially
parallel to the side surface of the pillar member.
2. The bridge pier structure of claim 1, wherein the lower end
portion and the upper end portion of the damper each include a
damper pin hole, wherein a substructure bracket including a
substructure pin hole is installed to the substructure, wherein a
pillar member bracket including a pillar member pin hole is
installed to the side surface of the pillar member, wherein a lower
pin inserted in the damper pin hole of the lower end portion of the
damper and the substructure pin hole forms a lower pin structure
configured to join the damper and the substructure, and wherein an
upper pin inserted in the damper pin hole of the upper end portion
of the damper and the pillar member pin hole forms an upper pin
structure configured to join the damper and the pillar member.
3. The bridge pier structure of claim 1, wherein the pillar member
has a rectangular cross section, and the side surfaces of the
pillar member are flat surfaces, wherein a pair of the dampers is
disposed parallel to at least one of the side surfaces of the
pillar member, and wherein a distance between the upper end
portions of the pair of the dampers is different from a distance
between the lower end portions of the pair of the dampers.
4. The bridge pier structure of claim 2, wherein the substructure
includes a base having an upper surface projecting from ground, and
wherein the substructure bracket is provided on the upper surface
of the base.
5. The bridge pier structure of claim 1, wherein the damper is an
axial damper, a shear damper, a viscoelastic damper, a bending
damper, a cylinder-piston damper, a buckling-restrained brace, an
unbonded brace, a hysteresis damper, or a friction damper.
6. The bridge pier structure of claim 1, wherein the pillar member
has a cut-off reinforced concrete structure including a full-length
reinforcing bar disposed over a full length of the pillar member in
a height direction and a lower reinforcing bar disposed in a lower
area of the pillar member in the height direction, and the upper
end portion of the damper is joined to the side surface of the
pillar member at a position above an upper end of the lower
reinforcing bar.
7. The bridge pier structure of claim 1, wherein the damper
includes an axial force member, a stiffener stiffening the axial
force member, a first connection member connected to one end
portion of the axial force member and one end portion of the
stiffener, and a second connection member connected to an other end
portion of the axial force member, and wherein the axial force
member has a length equal to or shorter than a length so that a
value of energy absorbed by the pillar member when the damper is
not installed to the pillar member and the pillar member deforms
from an allowable pillar member displacement allowed for the pillar
member to a maximum design displacement determined by design energy
of the pillar member is equal to energy absorbed by the damper from
start of deformation of the damper to displacement to a
displacement corresponding to the allowable pillar member
displacement.
8. The bridge pier structure of claim 7, wherein a stopper is
formed to project from an outer circumference of the second
connection member, and, when the axial force member contracts, the
stopper comes into contact with an other end portion of the
stiffener.
9. The bridge pier structure of claim 7, wherein a stopper is
formed to project from an outer circumference of the second
connection member, wherein an other end portion of the stiffener is
formed with a first reaction force portion and a second reaction
force portion facing each other across the stopper, and wherein the
stopper comes into contact with the first reaction force portion of
the stiffener when the axial force member contracts, and the
stopper comes into contact with the second reaction force portion
of the stiffener when the axial force member extends.
10. The bridge pier structure of claim 8, wherein the stiffener is
stiffened by a second stiffener, and one end portion of the second
stiffener is connected to the first connection member.
Description
TECHNICAL FIELD
[0001] The present invention relates to a bridge pier structure,
and more particularly to a bridge pier structure for enhancing the
earthquake resistance of a bridge pier of a bridge or a road, a
pillar member of a civil engineering structure such as a floodgate,
or a pillar member of an architectural structure such as a
building.
BACKGROUND ART
[0002] Inventions have been disclosed in which, for seismic
reinforcement of a pillar member of a civil engineering structure
or an architectural structure, diagonal members having hysteresis
damping characteristics are disposed in a brace manner between the
target pillar member and a footing with the pillar member
installed, to thereby support a horizontal load in an earthquake,
increase a horizontal load capacity of the pillar member, and
reduce horizontal displacement (see Patent Literature 1, for
example).
CITATION LIST
Patent Literature
[0003] Patent Literature 1 Japanese Unexamined Patent Application
Publication No. 2003-74019 (pages 3 to 4 and FIG. 1)
SUMMARY OF INVENTION
Technical Problem
[0004] According to the invention disclosed in Patent Literature 1,
the diagonal members extend or contract owing to deformation (tilt
relative to the footing) of the pillar member in the earthquake.
Therefore, the diagonal members exhibit hysteresis damping
performance, thereby obtaining an effect of damping vibration of
the pillar structure, reducing a seismic load, and enabling
efficient seismic reinforcement.
[0005] According to this invention, however, the diagonal members
are installed to the pillar member in a brace manner to extend
laterally from the pillar member, and thus ends of the diagonal
members joined to the footing project extensively from the outer
circumference of the pillar member. That is, the diagonal members
serving as reinforcing members occupy a large area.
[0006] Therefore, there is a problem in that the invention is not
applicable to a case in which a bridge pier of a bridge, for
example, is located close to a space-occupying structure, such as a
road, a path, or an embankment. Further, there is another problem
in that the invention is not applicable to a case in which the
bridge pier is located in a river, a lake, a marsh, or a sea area,
for example, since the reinforcing members project extensively to a
water area and occupy a large area, thereby obstructing a river
basin area, for example.
[0007] The present invention provides a bridge pier structure that
solves the above-described problems and is capable of reducing the
seismic load while curtailing the area occupied by the reinforcing
members, without projecting extensively from the outer
circumference of the pillar member.
Solution to Problem
[0008] (1) A bridge pier structure according to the present
invention includes a damper having damping characteristics, a
substructure joined with a lower end portion of the damper, and a
pillar member provided upright on the substructure, a side surface
of the pillar member being joined with an upper end portion of the
damper. The damper is substantially parallel to the side surface of
the pillar member.
[0009] (2) Further, in (1) described above, the lower end portion
and the upper end portion of the damper each include a damper pin
hole, and a substructure bracket including a substructure pin hole
is installed to the substructure. A pillar member bracket including
a pillar member pin hole is installed to the side surface of the
pillar member.
[0010] A lower pin inserted in the damper pin hole of the lower end
portion of the damper and the substructure pin hole forms a lower
pin structure configured to join the damper and the
substructure.
[0011] An upper pin inserted in the damper pin hole of the upper
end portion of the damper and the pillar member pin hole forms an
upper pin structure configured to join the damper and the pillar
member.
[0012] (3) Further, in (1) described above, the pillar member has a
rectangular cross section, and the side surfaces of the pillar
member are flat surfaces.
[0013] A pair of the dampers is disposed parallel to at least one
of the side surfaces of the pillar member.
[0014] A distance between the upper end portions of the pair of the
dampers is different from a distance between the lower end portions
of the pair of the dampers.
[0015] (4) Further, in (2) described above, the substructure
includes a base having an upper surface projecting from ground, and
the substructure bracket is provided on the upper surface of the
base.
[0016] (5) Further, in (1) described above, the damper is an axial
damper, a shear damper, a viscoelastic damper, a bending damper, a
cylinder-piston damper, a buckling-restrained brace, an unbonded
brace, a hysteresis damper, or a friction damper.
[0017] (6) Further, in (1) described above, the pillar member has a
"cut-off" reinforced concrete structure including a full-length
reinforcing bar disposed over a full length of the pillar member in
a height direction and a lower reinforcing bar disposed in a lower
area of the pillar member in the height direction, and the upper
end portion of the damper is joined to the side surface of the
pillar member at a position above an upper end of the lower
reinforcing bar.
[0018] (7) Further, in (1) described above, the damper includes an
axial force member, a stiffener stiffening the axial force member,
a first connection member connected to one end portion of the axial
force member and one end portion of the stiffener, and a second
connection member connected to an other end portion of the axial
force member.
[0019] The axial force member has a length equal to or shorter than
a length so that a value of energy absorbed by the pillar member
when the damper is not installed to the pillar member and the
pillar member deforms from an allowable pillar member displacement
allowed for the pillar member to a maximum design displacement
determined by design energy of the pillar member is equal to energy
absorbed by the damper from start of deformation of the damper to
displacement to a displacement corresponding to the allowable
pillar member displacement.
[0020] (8) Further, in (7) described above, a stopper is formed to
project from an outer circumference of the second connection
member, and, when the axial force member contracts, the stopper
comes into contact with an other end portion of the stiffener.
[0021] (9) Further, in (7) described above, a stopper is formed to
project from an outer circumference of the second connection
member, and an other end portion of the stiffener is formed with a
first reaction force portion and a second reaction force portion
facing each other across the stopper.
[0022] The stopper comes into contact with the first reaction force
portion of the stiffener when the axial force member contracts, and
the stopper comes into contact with the second reaction force
portion of the stiffener when the axial force member extends.
[0023] (10) Further, in (8) described above, the stiffener is
stiffened by a second stiffener, and one end portion of the second
stiffener is connected to the first connection member.
Advantageous Effects of Invention
[0024] (i) In the bridge pier structure according to the present
invention, the dampers having the damping characteristics have end
portions each joined to the respective side surfaces of the pillar
member provided upright on the substructure (bridge pier side
surfaces of a bridge pier provided upright on a footing, for
example). Therefore, the dampers extend or contract owing to the
deformation (tilt relative to the substructure) of the pillar
member in an earthquake. Thus, a vibration damping effect is
obtained, a seismic load is reduced, and efficient seismic
reinforcement is provided.
[0025] Further, since the dampers are installed substantially
parallel to the side surfaces of the pillar member, the dampers do
not project extensively from the outer circumference of the pillar
member, and the area occupied by the dampers serving as reinforcing
members is small. Thus, the bridge pier structure according to the
present invention is also applicable to a case in which the bridge
pier is located close to a space-occupying structure, such as a
road, a path, or an embankment, for example, and a case in which
the bridge pier is located in a river, a lake, a marsh, or a sea
area, for example.
[0026] (ii) Further, since the pillar member, the dampers, and the
substructure are joined together by the pin structures, the dampers
are subjected only to force acting in the axial direction thereof
and not to force that bends the dampers. Therefore, the designing
of the dampers is simplified, and the damping characteristics of
the dampers are sufficiently exhibited.
[0027] (iii) Since the pair of the dampers is parallel to the flat
side surface of the pillar member and arranged in a triangular or
trapezoidal shape, the effect of damping earthquake vibration in a
direction parallel to the side surface is obtained by the pair of
the dampers. That is, since it is possible to limit the side
surface of the pillar member to which the dampers are installed,
the degree of freedom is increased in selecting the side surface to
which the dampers are installed. It is therefore possible to
improve the appearance by not installing the dampers to some of the
side surfaces.
[0028] (iv) Further, the lower end portions of the dampers are
connected to the substructure brackets provided on the upper
surfaces of the bases projecting from the ground, and the dampers
are separated from the ground. Therefore, the corrosion of the
dampers is suppressed, and the replacement of the dampers is
simplified.
[0029] (v) Further, the dampers have the hysteresis damping
characteristics, and are commonly used. Therefore, the dampers are
easily selected and procured, and make it possible to manufacture
the bridge pier structure at low cost.
[0030] (vi) Further, the pillar member has the cut-off reinforced
concrete structure, and the upper end portions of the dampers are
located at positions higher than a cut-off section. Therefore, the
area of the pillar member higher than the cut-off section is also
reinforced and improved in earthquake resistance. In addition, the
area occupied by the dampers serving as the reinforcing members is
small, and thus restrictions on installation sites are reduced.
[0031] (vii) Further, the axial force member has the length equal
to or shorter than the length so that the value of the energy
absorbed by the pillar member when the pillar member deforms from
the allowable pillar member displacement to the maximum design
displacement is equal to the energy absorbed by the dampers until
the displacement to an allowable damper displacement corresponding
to the allowable pillar member displacement. Therefore, the
earthquake resistance is more reliably improved.
[0032] (viii) Further, the stopper is provided, and the axial force
member and the stiffener both support compression force. Therefore,
the buckling of the axial force member is prevented, and the
earthquake resistance is improved.
[0033] (ix) Further, since the stopper is provided and the axial
force member and the stiffener both support the compression force,
the buckling of the axial force member is prevented. Further, since
the axial force member and the stiffener both support tensile
force, a plastic deformation amount of the axial force member is
reduced, and the earthquake resistance is improved.
[0034] (x) Further, since the second stiffener is provided, the
buckling of the axial force member is more reliably suppressed, and
the earthquake resistance is further improved.
BRIEF DESCRIPTION OF DRAWINGS
[0035] FIG. 1 is a side view illustrating a bridge pier structure
according to Embodiment 1 of the present invention.
[0036] FIG. 2 is a front view illustrating the bridge pier
structure according to Embodiment 1 of the present invention.
[0037] FIG. 3 is a cross-sectional view of a plan view illustrating
the bridge pier structure according to Embodiment 1 of the present
invention (along arrow A in FIG. 1).
[0038] FIG. 4 is a front view illustrating the bridge pier
structure according to Embodiment 1 of the present invention,
depicting deformation of the bridge pier structure in an
earthquake.
[0039] FIG. 5 is a front view illustrating the bridge pier
structure according to Embodiment 1 of the present invention,
depicting the relationship between force acting in the earthquake
and a deformation amount.
[0040] FIG. 6 is a correlation diagram illustrating the bridge pier
structure according to Embodiment 1 of the present invention,
depicting the relationship between a seismic load and a horizontal
displacement amount.
[0041] FIG. 7A is a front view illustrating a bridge pier structure
according to Embodiment 2 of the present invention.
[0042] FIG. 7B is a plan view illustrating the bridge pier
structure according to Embodiment 2 of the present invention,
depicting parts of the bridge pier structure.
[0043] FIG. 8 is a left side view illustrating a bridge pier
structure according to Embodiment 3 of the present invention.
[0044] FIG. 9 is a right side view illustrating the bridge pier
structure according to Embodiment 3 of the present invention.
[0045] FIG. 10 is a front view illustrating the bridge pier
structure according to Embodiment 3 of the present invention.
[0046] FIG. 11 is a cross-sectional view of a plan view
illustrating the bridge pier structure according to Embodiment 3 of
the present invention (along arrow A in FIG. 8).
[0047] FIG. 12 is a left side view illustrating the bridge pier
structure according to Embodiment 3 of the present invention,
depicting deformation of the bridge pier structure in an
earthquake.
[0048] FIG. 13A is a side view illustrating a bridge pier structure
according to Embodiment 4 of the present invention, depicting a
section of a part thereof.
[0049] FIG. 13B is a moment diagram illustrating the bridge pier
structure according to Embodiment 4 of the present invention,
depicting the distribution of bending moment.
[0050] FIG. 13C is a moment diagram illustrating the bridge pier
structure according to Embodiment 4 of the present invention,
depicting the distribution of bending moment when comparative
dampers are installed.
[0051] FIG. 14 illustrates the bridge pier structure according to
Embodiment 4 of the present invention, and (a) and (b) are side
views each depicting a part (damper) of the bridge pier
structure.
[0052] FIG. 15A is a correlation diagram illustrating the bridge
pier structure according to Embodiment 4 of the present invention,
depicting the relationship between a seismic load and a horizontal
displacement amount.
[0053] FIG. 15B is a correlation diagram illustrating the bridge
pier structure according to Embodiment 4 of the present invention,
depicting the relationship between force and a displacement amount
for illustrating how to determine the length of a part (an axial
force member of a damper) of the bridge pier structure.
[0054] FIG. 16 illustrates a bridge pier structure according to
Embodiment 5 of the present invention, and (a), (b), and (c) are
side views each depicting a part (damper) of the bridge pier
structure.
[0055] FIG. 17 is a correlation diagram illustrating the bridge
pier structure according to Embodiment 5 of the present invention,
depicting the relationship between a seismic bad on a bridge pier
and a horizontal displacement amount of the bridge pier.
[0056] FIG. 18 is a side view illustrating a bridge pier structure
according to Embodiment 6 of the present invention.
[0057] FIG. 19 is a correlation diagram illustrating the bridge
pier structure according to Embodiment 6 of the present invention,
depicting the relationship between a seismic load and a horizontal
displacement amount.
DESCRIPTION OF EMBODIMENTS
Embodiment 1
[0058] FIGS. 1 to 3 illustrate a bridge pier structure according to
Embodiment 1 of the present invention. FIG. 1 is a side view, FIG.
2 is a front view, and FIG. 3 is a cross-sectional view of a plan
view (along arrow A in FIG. 1). Respective parts are schematically
illustrated, and the present invention is not limited to the
illustrated embodiment (in shape and relative size).
(Bridge Pier Structure)
[0059] In FIGS. 1 to 3, a bridge pier structure 100 has dampers
30a, 30b, 30c, and 30d having damping characteristics and having
respective lower end portions joined to an upper surface 11 of a
footing (same as substructure) 10 and respective upper end portions
joined to bridge pier side surfaces 21a, 21b, 21c, and 21d of a
bridge pier (same as pillar member) 20 provided upright on the
footing 10.
[0060] Herein, the dampers 30a, 30b, 30c, and 30d are substantially
parallel to the bridge pier side surfaces 21, 21b, 21c, and 21d,
respectively. In the following description of members having the
same structure, the suffixes "c," and "d" added to the reference
signs of the members and parts may be omitted for the convenience
of description.
[0061] Although the bridge pier structure 100 includes the bridge
pier 20 as a pillar member, the present invention is not limited
thereto, and may include a pillar member installed on a
substructure to support a superstructure.
[0062] The lower end portions and the upper end portions of the
dampers 30 include not-illustrated damper pin holes. Meanwhile,
footing brackets 12 including not-illustrated footing pin holes are
installed to the upper surface 11 of the footing 10, and bridge
pier brackets (same as pillar member brackets) 22 including
not-illustrated pier pin holes are installed to the bridge pier
side surfaces 21 of the bridge pier 20.
[0063] Further, lower pins 31 inserted in the not-illustrated
damper pin holes of the lower end portions of the dampers 30 and
the not-illustrated footing pin holes form footing-side pin
structures that join the dampers 30 and the footing 10.
[0064] Further, upper pins 32 inserted in the not-illustrated
damper pin holes of the upper end portions of the dampers 30 and
the not-illustrated pier pin holes form pier-side pin structures
that join the dampers 30 and the bridge pier 20.
[0065] The footing 10 is buried in ground 90 with the upper surface
11 of the footing 10 located below a surface of the ground 90
(hereinafter referred to as the aground surface 92), and is
supported by multiple piles 91 placed in the ground 90.
[0066] Further, beams 40a and 40c are installed on the bridge pier
side surfaces 21a and 21c, respectively, and girders 51a and 52a
and girders 51c and 52c are installed on an upper surface 41a of
the beam 40a and an upper surface 41c of the beam 40c,
respectively, and support a floorboard (same as superstructure) 60.
Therefore, the bridge pier side surfaces 21a and 21c are parallel
to a bridge axis direction (indicated by arrow).
(Operations)
[0067] FIGS. 4 to 6 illustrate the bridge pier structure according
to Embodiment 1 of the present invention. FIG. 4 is a front view
depicting deformation of the bridge pier structure in an
earthquake. FIG. 5 is a front view depicting the relationship
between force acting in the earthquake and a deformation amount.
FIG. 6 is a correlation diagram depicting the relationship between
a seismic load and a horizontal displacement amount. Respective
parts are schematically illustrated, and the same parts as the
parts illustrated in FIGS. 1 to 3 are designated by the same
reference signs.
[0068] In FIG. 4, the bridge pier 20 (the bridge pier side surfaces
21a and 21c) is installed perpendicularly to the upper surface 11
of the footing 10 before the occurrence of the earthquake. Thus,
the damper 30a (a line connecting the center of the lower pin 31a
and the center of the upper pin 32a) and the damper 30c (a line
connecting the center of the lower pin 31c and the center of the
upper pin 32c) are perpendicular to the upper surface 11 (both
indicated by broken lines).
[0069] Then, as the earthquake occurs, an area of the bridge pier
20 close to the lower end thereof is bent to tilt relative to the
upper surface 11 of the footing 10, and the bridge pier side
surface 21a extends and the bridge pier side surface 21c contracts.
Thus, the upper end portion of the damper 30a (the upper pin 32a)
moves diagonally upward, and thus the damper 30a extends by a
distance (hereinafter referred to as "extension amount") 34a.
Meanwhile, the upper end portion of the damper 30c moves diagonally
downward, and thus the damper 30c contracts by a distance
(hereinafter referred to as "contraction amount") 34c.
[0070] In FIG. 5, the relationship between seismic force acting on
a head portion of the bridge pier 20 (hereinafter referred to as
the "damper resistance Pd") and force acting on the dampers 30
(hereinafter referred to as the "damper axial force F") is
obtained. The height of the bridge pier 20 is represented as "H,"
the displacement amount in the horizontal direction of the head
portion of the bridge pier 20 (same as horizontal bridge pier
displacement amount) is represented as ".delta.," the height of the
dampers 30 is represented as "D," the interval between the dampers
30a and 30c is represented as "L," and the extension amount of the
damper 30a (same as the contraction amount of the damper 30c) is
represented as "d."
[0071] Herein, bending moment due to the damper resistance Pd and
bending moment due to the damper axial force F are balanced, and
"Pd.times.H=F.times.L" holds. Therefore, the damper resistance Pd
is calculated from "Pd=F.times.L/H" That is, the damper resistance
Pd is increased as the installation interval L between the dampers
30 is increased (widened).
[0072] Further, since the extension amount d of the damper 30a and
the horizontal bridge pier displacement amount .delta. of the head
portion of the bridge pier 20 have a relationship
".delta./H=2.times.d/L," the horizontal bridge pier displacement
amount .delta. is calculated from
".delta.=2.times.d.times.H/L."
[0073] When the cross section area and the modulus of elasticity of
the dampers 30 are represented as "A" and "E," respectively, the
extension amount d of the damper 30a is calculated from
"d=F.times.D/(A.times.E)" based on "F=A.times.E.times.d/D."
[0074] In FIG. 6, the vertical axis represents the seismic load
acting on the bridge pier 20, and the horizontal axis represents
the horizontal bridge pier displacement amount (.delta.) of the
bridge pier 20. In FIG. 6, as to the bridge pier 20 before the
dampers 30 are installed, the seismic load is elastically and
gradually increased until the horizontal bridge pier displacement
amount (.delta.) reaches a displacement amount at which the bridge
pier 20 yields (hereinafter referred to as the "bridge pier yield
displacement amount .delta.y"), and the seismic load remains at a
constant value after the horizontal bridge pier displacement amount
(.delta.) reaches the bridge pier yield displacement amount
.delta.y, irrespective of the increase in the horizontal bridge
pier displacement amount (.delta.).
[0075] Meanwhile, as to the dampers 30 per se, the seismic load is
elastically and gradually increased until the horizontal bridge
pier displacement amount (.delta.) reaches a displacement amount at
which the dampers 30 yield (hereinafter referred to as the "damper
yield displacement amount .delta.dy"), and the seismic load remains
at a constant value after the horizontal bridge pier displacement
amount (.delta.) reaches the damper yield displacement amount
.delta.dy, irrespective of the increase in the horizontal bridge
pier displacement amount (.delta.).
[0076] Herein, the damper yield displacement amount .delta.dy is
larger in value than the bridge pier yield displacement amount
.delta.y.
[0077] As to the bridge pier 20 to which the dampers 30 are
installed, therefore, the behavior of the bridge pier 20 before the
dampers 30 are installed and the behavior of the dampers 30 alone
are combined to form a behavior indicated by a solid line in FIG.
6.
[0078] In this case, the following holds:
[0079] The extension/contraction amount (extension amount
d=contraction amount d) of the dampers 30 at the time of yielding
is proportional to the height D of the dampers 30.
[0080] It is possible to adjust the horizontal bridge pier
displacement amount .delta., which is an extension/contraction
amount at the time of yielding, by adjusting the height D of the
dampers 30.
[0081] It is possible to adjust the timing of yielding of the
dampers 30 relative to the horizontal bridge pier displacement
amount .delta. at the time of yielding of the bridge pier 20 by
adjusting the height D of the damper 30.
[0082] Adjustment for preventing the dampers 30 from yielding is
possible by adjusting the height D of the dampers 30, if the bridge
pier 20 is in the range of elasticity.
[0083] As described above, the bridge pier structure 100 provides
efficient seismic reinforcement of the bridge pier 20. Further, the
dampers 30 do not project extensively from the bridge pier side
surfaces 21 of the bridge pier 20, and the area occupied by the
dampers 30 serving as reinforcing members is small. The bridge pier
structure 100 is therefore applicable to a case in which the bridge
pier 20 is located close to a space-occupying structure, such as a
road, a path, or an embankment, for example, and a case in which
the bridge pier 20 is located in a river, a lake, a marsh, or a sea
area, for example.
[0084] Further, since the dampers 30 are joined by the pin
structures, the dampers 30 are subjected only to the force in the
axial direction thereof and not to force that bents the dampers 30.
Thus, the designing of the dampers 30 is simplified, and the
damping characteristics of the dampers 30 are sufficiently
exhibited.
[0085] Further, the dampers 30 are not limited to the one described
above as long as the dampers 30 have the damping characteristics,
and the dampers 30 are commonly used. Thus, the dampers 30 are
easily selected and procured, and it is possible to manufacture the
bridge pier structure 100 at low cost.
Embodiment 2
[0086] FIG. 7A is a front view illustrating a bridge pier structure
according to Embodiment 2 of the present invention. FIG. 7B is a
plan view illustrating the bridge pier structure according to
Embodiment 2 of the present invention, depicting parts of the
bridge pier structure. Parts the same as or corresponding to those
in Embodiment 1 are designated by the same reference signs, and
description of parts thereof will be omitted. Further, respective
parts are schematically illustrated, and the present invention is
not limited to the illustrated embodiment (in shape and relative
size).
(Bridge Pier Structure)
[0087] In FIGS. 7A and 7B, a bridge pier structure 200 includes
bases 13a, 13b, 13c, and 13d standing on the upper surface 11 of
the footing 10, and footing brackets 12a, 12b, 12c, and 12d are
installed on the bases 13a, 13b, 13c, and 13d. The configurations
other than these points are the same as those in the bridge pier
structure 100 (Embodiment 1).
[0088] In this case, respective upper surfaces of the bases 13a,
13b, 13c, and 13d project upward from the ground surface 92, and
thus the footing brackets 12a, 12b, 12c, and 12d are exposed above
the ground surface 92.
[0089] Thus, the corrosion of the dampers 30 is prevented, and it
is unnecessary to dig the ground 90 when the dampers 30 themselves
or members forming the dampers 30 are to be replaced.
Embodiment 3
[0090] FIGS. 8 to 11 illustrate a bridge pier structure according
to Embodiment 3 of the present invention. FIG. 8 is a left side
view, FIG. 9 is a right side view, FIG. 10 is a front view, and
FIG. 11 is a cross-sectional view of a plan view (along arrow A in
FIG. 8). Parts the same as or corresponding to those in Embodiment
1 are designated by the same reference signs, and description of
parts thereof will be omitted. Further, respective parts are
schematically illustrated, and the present invention is not limited
to the illustrated embodiment (in shape and relative size).
(Bridge Pier Structure)
[0091] In FIGS. 8 to 11, a bridge pier structure 300 includes the
bases 13a and 13c along the bridge pier side surfaces 21a and 21c
of the bridge pier 20 on the upper surface 11 of the footing 10,
and has no bases along the bridge pier side surfaces 21b and 21d.
Further, dampers 30e and 30f are disposed parallel to the bridge
pier side surface 21a, and dampers 30g and 30h are disposed
parallel to the bridge pier side surface 21c. No dampers are
disposed along the bridge pier side surfaces 21b and 21d.
[0092] The configurations other than the configuration for
disposing the dampers 30e, 30f, 30g, and 30h are the same as those
in the bridge pier structure 200 (Embodiment 2). Further, the
dampers 30e, 30f, 30g, and 30h are the same as the dampers 30.
Further, in the following description of members having the same
structure, the suffixes "e," "f," and "h" added to the reference
signs of the members and parts may be omitted for the convenience
of description.
[0093] Footing brackets 12e and 12f each including a
not-illustrated footing pin hole are installed to the base 13a
extending along the bridge pier side surface 21a, and a bridge pier
bracket 22a including a not-illustrated pier pin hole is installed
at the center in the horizontal direction of the bridge pier side
surface 21a.
[0094] Further, similarly, Footing brackets 12g and 12h each
including a not-illustrated footing pin hole are installed to the
base 13c extending along the bridge pier side surface 21c, and a
bridge pier bracket 22c including a not-illustrated pier pin hole
is installed at the center in the horizontal direction of the
bridge pier side surface 21c.
[0095] On the side of the bridge pier side surface 21a, a lower pin
31e inserted in a damper pin hole (not illustrated) provided in the
damper 30e and the corresponding footing pin hole forms a
footing-side pin structure, and the upper pin 32a inserted in a
damper pin hole (not illustrated) provided in the damper 30e and
the pier pin hole forms a pier-side pin structure. Similarly, a
lower pin 31f inserted in a damper pin hole (not illustrated)
provided in the damper 30f and the corresponding footing pin hole
forms a footing-side pin structure, and the upper pin 32a inserted
in a damper pin hole (not illustrated) provided in the damper 30f
and the pier pin hole forms a pier-side pin structure.
[0096] The dampers 30e and 30f are therefore pin-connected by the
upper pin 32a at the upper ends thereof, forming an inverse V
shape.
[0097] Further, similarly, on the side of the bridge pier side
surface 21c, the dampers 30g and 30h are pin-connected by the upper
pin 32c at the upper ends thereof, forming an inverse V shape.
(Operations)
[0098] FIG. 12 is a left side view illustrating the bridge pier
structure 300 according to Embodiment 3 of the present invention,
depicting deformation of the bridge pier structure 300 in an
earthquake. Respective parts are schematically illustrated, and the
same parts as the parts illustrated in FIGS. 8 to 10 are designated
by the same reference signs.
[0099] In FIG. 12, the bridge pier 20 (the bridge pier side
surfaces 21b and 21d) is installed perpendicularly to the upper
surface 11 of the footing 10 before the occurrence of the
earthquake. Thus, the dampers 30e and 30f form oblique sides of an
isosceles triangle (indicated by broken lines). The dampers 30g and
30h similarly form oblique sides of an isosceles triangle (not
illustrated).
[0100] Then, as the earthquake occurs, an area of the bridge pier
20 close to the lower end thereof is bent to tilt relative to the
upper surface 11 of the footing 10. Thus, respective upper end
portions of the dampers 30e and 30f (both pin-connected by the
upper pin 32a) move in a substantially horizontal direction (more
accurately, slightly diagonally downward). Thus, the damper 30e
extends by a distance represented as 34e (hereinafter referred to
as the "extension amount"), while the damper 30f contracts by a
distance represented as 34f (hereinafter referred to as the
"contraction amount").
[0101] Further, similarly, on the side of the bridge pier side
surface 21c, the damper 30g extends by the extension amount 34e,
while the damper 30h contracts by the contraction amount 34f (not
illustrated).
[0102] The bridge pier structure 300 therefore exhibits operations
and effects similar to those of the bridge pier structures 100 and
200 (Embodiments 1 and 2).
[0103] Although the upper end portion of the damper 30e and the
upper end portion of the damper 30f overlap each other in the
foregoing description, the present invention is not limited
thereto. The upper end portion of the damper 30e and the upper end
portion of the damper 30f may be separated from each other, as long
the distance between the upper end portion of the damper 30e and
the upper end portion of the damper 30f is different from the
distance between the lower end portion of the damper 30e and the
lower end portion of the damper 30f. That is, the dampers 30e and
30f may be arranged in a trapezoidal shape. In this case, the
distance between the upper end portions may be longer or shorter
than the distance between the lower end portions.
[0104] Further, the dampers 30e and 30f may form a triangular
shape, with the respective lower end portions of the dampers 30e
and 30f overlapping each other.
Embodiment 4
[0105] FIGS. 13 to 15 illustrate a bridge pier structure according
to Embodiment 4 of the present invention. FIG. 13A is a side view
of the bridge pier structure depicting a section of a part thereof,
FIG. 13B is a moment diagram depicting the distribution of bending
moment, and FIG. 130 is a moment diagram illustrating the
distribution of bending moment when comparative dampers are
installed. In FIG. 14, (a) and (b) are side views each depicting a
part (damper) of the bridge pier structure. FIG. 15A is a
correlation diagram depicting the relationship between a seismic
load and a horizontal displacement amount, and FIG. 15B is a
correlation diagram depicting the relationship between force and a
displacement amount for illustrating how to determine the length of
a part (an axial force member of a damper) of the bridge pier
structure.
[0106] Parts the same as or corresponding to those in Embodiment 1
are designated by the same reference signs, and description of
parts thereof will be omitted. Respective parts are schematically
illustrated, and the present invention is not limited to the
illustrated embodiment (in shape and relative size).
(Cut-Off Section)
[0107] In a bridge pier structure 400 in FIG. 13A, the bridge pier
20 serving as a pillar member in the bridge pier structure 100 is
replaced by a bridge pier 420 having a "cut-off section", and the
dampers 30 is replaced by dampers 430.
[0108] That is, the bridge pier 420 includes full-length
reinforcing bars 421 disposed over the full length of the bridge
pier 420 in the height direction, lower reinforcing bars 422
disposed in a lower portion of the bridge pier 420 in the height
direction, and concrete 423, and a cut-off section 424 is formed at
a height corresponding to respective upper ends of the lower
reinforcing bars 422. Further, on the bridge pier side surfaces 21b
and 21d of the bridge pier 420, bridge pier brackets 22b and 22d
are provided at positions higher than the cut-off section 424.
[0109] Further, respective upper end portions of the dampers 430b
and 430d (also collectively referred to as the dampers 430) are
connected to the bridge pier brackets 22b and 22d. That is, when
the distance from the upper surface 11 of the footing 10 to the
upper ends of the lower reinforcing bars 422 is referred to as the
"minimum damper installation height K," the dampers 430 have a
length covering the "minimum damper installation height K."
[0110] Although the description has been given of a case in which
the dampers 430b and 430d are installed for the convenience of
description, the present invention is not limited thereto. Thus,
the same damper as the damper 430b may be each installed to four
surfaces of the bridge pier 420.
(Resisting Moment)
[0111] In FIG. 13B, seismic bending moment acting on the bridge
pier 420 (indicated by a right-downward sloping straight line) is
small at an upper portion of the bridge pier 420 and increases
toward the footing 10.
[0112] In accordance with this, the bridge pier 420 includes the
"cut-off section 424," at which the amount of reinforcing bars is
changed, at an intermediate position in the height direction of the
bridge pier 420. Therefore, the bending resistance (resisting
moment) of the bridge pier 420 is small at the upper portion of the
bridge pier 420 and large at a lower portion of the bridge pier
420, and sharply changes at the cut-off section 424 (indicated by a
dash-dotted line).
[0113] Further, since the dampers 430 are disposed in an area
including the cut-off section 424 at which the sharp change in the
resisting moment occurs, the value of the resisting moment is
increased in an area not reinforced by the lower reinforcing bars
422 (same as the area between the heights K and D) (indicated by a
thick solid line).
[0114] In FIG. 130, if dampers shorter than the "minimum damper
installation height K" (hereinafter referred to as the "comparative
dampers") are installed, the value of the resisting moment is
increased in the area lower than the cut-off section 424, that is,
the area reinforced by the full-length reinforcing bars 421 and the
lower reinforcing bars 422, but fails to be increased in an area
higher than the cut-off section 424, that is, an area not
reinforced by the lower reinforcing bars 422 (same as the area
between the heights D and K) (indicated by a thick solid line).
(Shape of Dampers)
[0115] In FIG. 14A, the damper 430 (referred to as the "damper
430L" for the convenience of description) includes an axial force
member 431 having an axial force pipe length L1, a stiffener 432
surrounding the axial force member 431, an upper ferrule 433
connected to respective upper end portions of the axial force
member 431 and the stiffener 432, an upper clevis 434 connected to
the upper ferrule 433, a lower ferrule/reinforcing pipe 435
connected to a lower end portion of the axial force member 431, and
a lower clevis 436 connected to the lower ferrule/reinforcing pipe
435.
[0116] In (b) of FIG. 14, the damper 430 (referred to as the
"damper 430S" for the convenience of description) is the same in
structure as the damper 430L, but an axial force pipe length L2 of
the axial force member 431 is shorter than the axial force pipe
length L1 in the damper 430L, and the length of the lower
ferrule/reinforcing pipe 435 is longer.
(Seismic Load)
[0117] In FIG. 15A, the vertical axis represents the seismic load
on the bridge pier 420, and the horizontal axis represents the
horizontal displacement amount of the bridge pier 420. The damper
430L with the long axial force member 431 elastically deforms until
the horizontal displacement amount of the bridge pier 420 reaches a
horizontal bridge pier displacement amount .delta.L. After the
horizontal displacement amount of the bridge pier 420 reaches the
horizontal bridge pier displacement amount .delta.L, the damper
430L plastically deforms under a constant load (indicated by a
dotted line). Meanwhile, the damper 430S with the short axial force
member 431 elastically deforms until the horizontal displacement
amount of the bridge pier 420 reaches a horizontal bridge pier
displacement amount .delta.S, which less than the horizontal bridge
pier displacement amount .delta.L. After the horizontal
displacement amount of the bridge pier 420 reaches the horizontal
bridge pier displacement amount .delta.S, the damper 430S
plastically deforms under a constant load (indicated by a broken
line).
[0118] Further, the body of the bridge pier 420 elastically deforms
until the horizontal displacement amount of the bridge pier 420
reaches the horizontal bridge pier displacement amount .delta..
After the horizontal displacement amount of the bridge pier 420
reaches the horizontal bridge pier displacement amount .delta., the
body of the bridge pier 420 plastically deforms under a constant
load (indicated by a dash-dotted line).
[0119] Thus, the seismic load supported by the bridge pier 420
equipped with the damper 430L changes at the horizontal bridge pier
displacement amounts .delta. and .delta.L (indicated by a thin
solid line). Further, the seismic load supported by the bridge pier
420 equipped with the damper 430S changes at the horizontal bridge
pier displacement amounts .delta. and .delta.S (indicated by a
thick solid line).
[0120] That is, the yield extension/contraction amount of the axial
force member 431 is proportional to the length of the axial force
member 431. Further, it is possible to adjust the yield
extension/contraction amount of the damper 430 by changing the
length of the axial force member 431, even if the full length of
the damper 430 is fixed.
[0121] In this case, the full length of the damper 430 needs to
cover the "minimum damper installation height K." In this case,
however, it is possible to provide a structure with good energy
absorption performance by reducing the length of the axial force
member 431 and increasing the length of the lower
ferrule/reinforcing pipe 435.
[0122] In FIG. 15B, the seismic load supported by the body of the
bridge pier 420 (to which the dampers 430 are not installed)
linearly declines after the bridge pier 420 plastically deforms to
an allowable displacement (same as allowable pillar member
displacement) amount .delta.u. Thereafter, the bridge pier 420
deforms with a constant value until a design displacement amount
.delta.0 determined by the design energy of the bridge pier 420.
That is, the bridge pier 420 absorbs energy E420 corresponding to
the area indicated by left-downward sloping lines even after the
bridge pier 420 is displaced to the allowable displacement amount
.delta.u.
[0123] Meanwhile, the damper 430S absorbs energy E430 corresponding
to the area indicated by right-downward sloping lines during the
displacement to the allowable displacement amount .delta.u.
Therefore, the length of the axial force member 431 of the damper
430S is determined so that the energy E430 equals or exceeds in
value the energy E420.
Embodiment 5
[0124] FIGS. 16 and 17 illustrate a bridge pier structure according
to Embodiment 5 of the present invention. In FIG. 16, (a), (b), and
(c) are side views each depicting a part (damper) of the bridge
pier structure. FIG. 17 is a correlation diagram illustrating the
relationship between a seismic load on a bridge pier and a
horizontal displacement amount of the bridge pier. Parts the same
as or corresponding to those in Embodiment 4 are designated by the
same reference signs, and description of parts thereof will be
omitted.
[0125] In a not-illustrated bridge pier structure 500, the dampers
430 in the bridge pier structure 400 (Embodiment 4) are replaced by
dampers 530T, 530V, or 530W described below. The parts other than
this point are the same as those in the bridge pier structure 400.
The changed parts will be described below.
(Stopper)
[0126] In (a) of FIG. 16, a stopper 531 projecting from the outer
circumference of the lower ferrule/reinforcing pipe 435 of the
damper 430S is installed to the damper 530T, and a gap A is formed
between an upper surface of the stopper 531 and a lower end of the
stiffener 432. After the axial force member 431 contracts and the
lower end of the stiffener 432 comes into contact with the stopper
531, therefore, the axial force member 431 and the stiffener 432
both support compressive force.
(Reaction Force Member)
[0127] In (b) of FIG. 16, the stopper 531 projecting from the outer
circumference of the lower ferrule/reinforcing pipe 435 of the
damper 430S is installed to the damper 530V, and a reaction force
member 535 is provided to the lower end of the stiffener 432. The
reaction force member 535 includes an upper reaction force plate
(same as upper reaction force portion) 532 forming the gap A from
the upper surface of the stopper 531, a lower reaction force plate
(same as lower reaction force portion) 534 forming the gap A from a
lower surface of the stopper 531, and a reaction force sleeve 533
connecting the upper reaction force plate 532 and the lower
reaction force plate 534 and housing the stopper 531.
[0128] After the axial force member 431 contracts and a lower
surface of the upper reaction force plate 532 comes into contact
with the upper surface of the stopper 531, therefore, the axial
force member 431 and the stiffener 432 both support the compressive
force. By contrast, after the axial force member 431 extends and an
upper surface of the lower reaction force plate 534 comes into
contact with the lower surface of the stopper 531, the axial force
member 431 and the stiffener 432 both support tensile force.
(Second Stiffener)
[0129] In (c) of FIG. 16, the damper 530W has a second stiffener
536 surrounding the stiffener 432 of the damper 530V and installed
to the upper ferrule 433.
[0130] Therefore, a gap .tangle-solidup. is provided between a
lower end of the second stiffener 536 and an upper surface of the
upper reaction force plate 532. Thus, the axial force member 431
and the stiffener 432 are stiffened by the second stiffener 536,
and the occurrence of buckling of the axial force member 431 and
the stiffener 432 is suppressed. Further, after the axial force
member 431 contracts and the lower surface of the upper reaction
force plate 532 comes into contact with the upper surface of the
stopper 531, the axial force member 431 and the stiffener 432 both
support the compressive force. Further, if the compression is
increased, the upper surface of the upper reaction force plate 532
comes into contact with the lower end of the second stiffener 536,
and three members of the axial force member 431, the second
stiffener 536, and the stiffener 432 support the compressive
force.
[0131] Since the number of members sharing the compressive force is
increased in the damper 530W, as described above, the compressive
force acting on each of the members is reduced, and thereby the
occurrence of bucking is suppressed.
[0132] In FIG. 17, the value of the gap .DELTA. between the upper
surface of the stopper 531 and the lower end of the stiffener 432
satisfies ".delta.u=2.DELTA.H/L" in the damper 530T. Herein,
.delta.u represents the allowable displacement (same as allowable
pillar member displacement) amount, H represents the height of the
bridge pier 420, and L represents the interval between the dampers
530T facing each other (see FIG. 5).
[0133] When the compressive force acts on the damper 530T and the
contraction amount reaches .DELTA., therefore, the lower end of the
stiffener 432 comes into contact with the stopper 531. Thus, the
compressive force acting thereafter is supported by both the axial
force member 431 and the stiffener 432, and the seismic load is
increased. Then, the displacement reaches .delta.v, and the
stiffener 432 starts to plastically deform (indicated by a broken
line).
[0134] Therefore, the reduction of the seismic load after the
displacement of the bridge pier 420 to the allowable displacement
amount .delta.u is less in the bridge pier 420 to which the dampers
530T are installed (indicated by a thick solid line) than in the
bridge pier 420 to which the dampers 430S (indicated by a thin
solid line) are installed.
Embodiment 6
[0135] FIGS. 18 and 19 illustrate a bridge pier structure according
to Embodiment 6 of the present invention. FIG. 18 is a side view of
the bridge pier structure, and FIG. 19 is a correlation diagram
depicting the relationship between a seismic load and a horizontal
displacement amount. Parts the same as or corresponding to those in
Embodiment 1 are designated by the same reference signs, and
description of parts thereof will be omitted. Respective parts are
schematically illustrated, and the present invention is not limited
to the illustrated embodiment (in shape and relative size).
(Preload)
[0136] In FIG. 18, a bridge pier structure 600 is the same as the
bridge pier structure 100, but the dampers 30b and 30d are
preloaded with force acting in a direction of lifting the
floorboard 60. That is, a portion of the bridge pier 20 between the
bridge pier brackets 22 and the upper surface 11 of the footing 10
is constantly (except in an earthquake) stretched by the dampers
30b and 30d.
[0137] Although the dampers 30b and 30d installed to the bridge
pier 20 are previously contracted, a mechanism for preloading the
dampers 30b and 30d is not limited. Further, although the
configuration that preloads the dampers 30b and 30d is illustrated,
the present invention is not limited thereto, and the dampers 30a
and 30c may also be preloaded. Further, preloading may similarly be
performed in the bridge pier structures 200 to 500 (Embodiments 2
to 5).
(Seismic Load)
[0138] In FIG. 19, the vertical axis represents a seismic load
acting on the bridge pier 20, and the horizontal axis represents a
horizontal displacement amount on the bridge pier 20. In FIG. 19,
the resistance of the body of the bridge pier 20 is linearly
reduced after becoming constant at resistance R20. Herein, if a
vertical load acting on the bridge pier 20 is large, the range of
the resistance R20 is small, and the resistance is reduced in a
relatively small range of the horizontal displacement (indicated by
a dotted line). By contrast, if the vertical load acting on the
bridge pier 20 is small, the range of the resistance R20 is
increased, and the resistance is reduced in a relatively large
range of the horizontal displacement (indicated by a dash-dotted
line).
[0139] Further, the resistance of the dampers 30b and 30d is
linearly increased and thereafter maintained constant at resistance
R30 (indicated by a broken line).
[0140] Therefore, if the dampers 30b and 30d not preloaded are
installed to the bridge pier 20, that is, if the vertical load
acting on the bridge pier 20 is large, the resistance is reduced at
a relatively small value of the horizontal displacement amount
(indicated by a thin solid line).
[0141] Meanwhile, if the preloaded dampers 30b and 30d are
installed to the bridge pier 20, that is, if the vertical load
acting on the bridge pier 20 is small, the resistance is reduced at
a relatively large value of the horizontal displacement amount
(indicated by a thick solid line). Herein, if the vertical bad due
to the own weight of the floorboard 60 and other factors and the
preload provided to each of the dampers 30b and 30d are represented
as "N2" and "ND," respectively, a vertical load N1 acting on a
lower portion of the bridge pier 20 (an area lower than the bridge
pier brackets 22b and 22d) is expressed as "N1=N2-2ND."
INDUSTRIAL APPLICABILITY
[0142] The present invention reliably obtains a large plastic
deformation amount (seismic energy absorption amount) and allows
installation in a relatively small space, and thus is widely
applicable as a vibration-damping, earthquake-resistant member of a
civil engineering structure or an architectural structure, not
limited to the bridge substructure or the like.
REFERENCE SIGNS LIST
[0143] 10 footing 11 upper surface 12a to 12h footing bracket 13a
to 13d base 20 bridge pier 21a to 21d bridge pier side surface 22a
to 22d bridge pier bracket 30a to 30h damper 31a to 31h lower pin
32a to 32d upper pin 34a extension amount 34c contraction amount
34e extension amount 34f contraction amount 40a, 40c beam 41a, 41c
upper surface 51a, 51c girder 52a, 52c girder 60 floorboard 90
ground 91 pile 92 ground surface 100 bridge pier structure
(Embodiment 1) 200 bridge pier structure (Embodiment 2) 300 bridge
pier structure (Embodiment 3) 400 bridge pier structure (Embodiment
4) 420 bridge pier 421 full-length reinforcing bar 422 lower
reinforcing bar 423 concrete 424 cut-off section 430 damper 430L
damper
[0144] 430S damper 430b damper 430d damper 431 axial force member
432 stiffener 433 upper ferrule 434 upper clevis 434d upper clevis
435 lower ferrule/reinforcing pipe 436 lower clevis 500 bridge pier
structure (Embodiment 5) 530T damper 530V damper
[0145] 530W damper 531 stopper 532 upper reaction force plate 533
reaction force sleeve 534 lower reaction force plate 535 reaction
force member 536 second stiffener 600 bridge pier structure
(Embodiment 6)
* * * * *