JP3989314B2 - Mooring system for floating bridge - Google Patents

Description

【００１６】
第３支持装置の左右両側に設置させた第４の支持装置（タイプ４）９は、図６（ａ）及び（ｂ）に示すように、ゴム板と金属板とを交互に多段に積層して成る公知の弾性拘束体９ａを主体とし、弾性拘束体９ａの下部は、無蓋容器９ｂの底面上に固定され、弾性拘束体９ａの上部には、ヒンジ９ｃが取り付けられている。ヒンジ９ｃのピン９ｄは、橋直（Ｙ軸）方向を指向し、「表１」に記載の機能を備えている。また、無蓋容器９ｂは、中央桁２ａの両サイド上面に固定され、ヒンジ９ｃの自由端は、緩衝桁２ｂ，２ｃの両サイド下面に固定される。
【００１７】
図４に示すように、橋台７と緩衝桁２ｂ，２ｃ間には、第１及び第２の２種類の支持装置１０，１１が設置されている。第２の支持装置１１は、第１の支持装置１０の両側に等しい間隔を隔てて設置されている。
【００１８】
橋台７の中央に設置された第１の支持装置（タイプ１）１０は、図７（ａ）及び（ｂ）に示すように、樋型の雌部１０ａと、雌部１０ａの長手（Ｘ軸）方向に移動可能な雄部１０ｂとから成り、雄部１０ｂは、フランジ付きの軸部１０ｃと、軸部１０ｃに回転自在に取り付けられた車輪１０ｄ、及びフランジ１０ｅの左右両側に固着された断面Ｌ字形の摺動部１０ｆから構成され、摺動部１０ｆは、雌部１０ａの内側に設けられた長手方向の溝１０ｇに沿って摺動するようになっている。また、雌部１０ａの溝側壁面には、雄部の車輪１０ｄが転動するレール１０ｈが設けられている。
【００１９】
第１の支持装置１０は、雌部１０ａによって雄部１０ｂの橋直（Ｙ軸）方向の変位が拘束されると共に、鉛直（Ｚ軸）方向の負反力が拘束されるが、雄部１０ｂの橋軸（Ｘ軸）、橋直（Ｙ軸）及び鉛直軸（Ｚ軸）回りの回転、及び鉛直（Ｚ軸）方向の正反力が許容されるようになっている（「表１」参照）。また、雌部１０ａは、橋台７の中央上面に固定され、雄部１０ｂは、緩衝桁２ｂ，２ｃの桁中央下面に固定される。
【００２０】
第１の支持装置１０の左右両側に設置させた第２の支持装置（タイプ２）１１は、図８（ａ）及び（ｂ）に示すように、主に、凹型レール１１ａと、該レール１１ａの長手（Ｘ軸）方向に移動可能な自在継手１１ｂから形成されている。その上、自在継手１１ｂの移動を円滑にするため、自在継手１１ｂの雄部１１ｃの下部に方形のスライド板１１ｄを固定すると共に、凹型レール１１ａの左右両側に細長い抑え板１１ｅが取り付けられている。また、スライド板１１ｄの横幅は、凹型レール１１ａの溝幅より、若干、狭くなっており、橋直（Ｙ軸）方向にも若干移動可能になっている。
【００２１】
この第２の支持装置１１は、鉛直軸（Ｚ軸）方向の正反力が拘束されるが、雄部１１ｃの橋軸（Ｘ軸）及び橋直（Ｙ軸）方向の変位、並びに橋軸（Ｘ軸）、橋直（Ｙ軸）、鉛直軸（Ｚ軸）回りの回転、及び鉛直軸（Ｚ軸）方向の負反力が許容されるようになっている（「表１」参照）。また、自在継手１１ｂの雌部１１ｆは、緩衝桁２ｂ，２ｃの両サイド下面に固定され、凹型レール１１ａは、自在継手１１ｂの雌部１１ｆに対向する橋台７上面に固定される。
【００２２】
図９及び図１０に示すように、定反力型の防舷装置１２は、主に、浮力体３上に斜め下向きに固定された本体１３と、該本体１３にその長手方向に所定の範囲だけ移動可能に取り付けられた角筒型の可動部１４と、可動部１４を支える２基の油圧ジャッキ１５と、可動部１４の先端に取り付けられた定反力型の防舷材１６とから構成され、係留索４は、定反力型の防舷材１６の先端に取り付けた天板１７のブラケット１８に取り付けられている。また、可動部１４の先端中央の上下両側には、それぞれ、ストッパー１９が取り付けられ、更に、可動部１４の先端と天板１７間には、複数の垂れ防止チェーン２０が架橋されている。図中、２１はカバーを示している。
【００２３】
次に、上記係留システムの作用について説明する。
道路橋として供用中（通常、風速２０ｍ／ｓｅｃ程度以下）において、橋軸（Ｘ軸）方向の水平外力に対しては、直列に連結した係留索４及び反力型防舷材１６によって抵抗する。
【００２４】
一方、浮体式道路橋１に橋直（Ｙ軸）方向からの水平力Ｆを受けた場合、図１１に示すように、橋直（Ｙ軸）方向に所定の距離を隔てて設置した２個の第３の支持装置９の弾性拘束体９ａには、浮力体３の橋直（Ｙ軸）方向の水平変位ｅに伴う鉛直軸（Ｚ軸）８回りの回転ρによる反力ρ′が生じ、この偶力反力ρ′により鉛直軸（Ｚ軸）８回りの回転変位が抑えられる。
【００２５】
即ち、上部構造２は、橋直（Ｙ軸）方向に所定の距離を隔てた２個の第３の支持部材９の弾性拘束体９ａの剪断バネによって鉛直軸（Ｚ軸）８回りの回転変位を弾性拘束することになる。
【００２６】
また、暴風時や大地震時には、浮力体３上に設置した定反力型の防舷材１６と、該定反力型の防舷材１６に直列に接続された係留索４、及び中央桁２ａと緩衝桁２ｂ，２ｃとの接続部に設置した弾性拘束体９ａなどが変位して浮体式道路橋１に作用する外力を発散させる。
【００２７】
以上の説明では、単純桁３連の上部構造と、２函の浮力体から構成される浮体式道路橋を例に説明したが、この発明は、複数の単純桁から成る上部構造と、１函以上の浮力体を備えた浮体式構造物に幅広く適用することができる。
【００２８】
また、係留索４は、上記のように、ケーブルやチェーンなどを用いるから、地盤変動による特性変化が少ないこと、復元特性を持つこと、過大な変位を防ぐことなどの長所を有する。また、メンテナンス上は、シムなどを用いてその長さを調整し、特性を管理できる長所を有する。また、全体特性としては、長周期化が計れ、地震力の低減が計れる長所を有する。
【００２９】
また、第４の支持装置９は、偶力による回転弾性バネとして作用するほか、弾性拘束体９ａの剛性の調整により、固有周期の調整、強いては変位制御が可能である。また、橋軸直角方向の軸に対しての回転が自由であるため、上部構造２は、地盤変動の影響による応力が発生しないという長所を有する。
【００３０】
また、定反力型の防舷材１６は、エネルギーを吸収することから免震機能を有する。また、ノックオフ機能、つまり、トリガー機能を有する。また、全体機能として、長周期化が計れ、地震力の低減が計れる長所を有する。
【００３１】
上記のように、係留索４と定反力型防舷材１６とを直列に結合すると、各々の長所が加算されると共に、復元性を持つことにより、道路橋としての使用性が向上する。また、定反力性を持つことにより、衝撃的な荷重への対応性が向上し、耐荷性が向上する。
【００３２】
上記係留索４及び定反力型防舷材１６に、更に、弾性拘束体としての第４の支持装置９が加わることにより、上部構造２の橋軸直角方向変位が制御可能となり、平面線形の変動量を低減でき、以て、道路橋としての使用性が向上する。
【００３３】
また、橋直方向運動の固有周期の調整が可能であり、その結果、定反力性を持つことにより、地震や波浪の卓越周期から固有周期を外すことが可能となり、耐荷性が向上する。
【００３４】
【発明の効果】
上記のように、この発明は、橋面を構成する複数の上部構造と、該上部構造同士を支持する１以上の浮力体、及びこれらを係留する係留装置から成る浮体式橋梁において、前記浮力体を、該浮力体に設置した定反力型防舷材と、該定反力型防舷材に直列に接続させた係留索とによって地盤に固定し、且つ、前記上部構造同士を、少なくとも鉛直軸回りの回転自由度を有する枢支手段により枢支すると共に、該枢支手段の両側に所定の間隔を隔てて前記上部構造の鉛直軸回りの回転を拘束する拘束手段を設置するので、道路橋として供用する場合などには、橋梁の変位を許容値以内に収めることが可能となった。
【００３５】
一方、暴風時や大地震時には、橋梁の変位を、ある程度、許して橋梁に作用する外力を発散させることができるので、橋梁の破損などを免れることが可能となった。
【図面の簡単な説明】
【図１】この発明の係留システムを適用した浮体式橋梁の側面図である。
【図２】図１の浮体式橋梁の平面図である。
【図３】図２のＡ−Ａ′断面図である。
【図４】図２のＢ−Ｂ′断面図である。
【図５】（ａ）第３支持装置の一部断面を含む正面図、（ｂ）第３支持装置の一部断面を含む側面図である。
【図６】（ａ）第４支持装置の一部断面を含む正面図、（ｂ）第４支持装置の一部断面を含む側面図である。
【図７】（ａ）第１支持装置の横断面、（ｂ）第１支持装置の一部断面を含む側面図である。
【図８】（ａ）第２支持装置の一部断面を含む正面図、（ｂ）第２支持装置の一部断面を含む側面図である。
【図９】定反力型防舷装置の平面図である。
【図１０】図９のＣ−Ｃ′断面図である。
【図１１】この発明に係る浮体式橋梁係留システムの作用説明図である。
【符号の説明】
１ 浮体式橋梁
２ 上部構造
３ 浮力体
４ 係留索
５ 地盤
８ 枢支手段
９ 拘束手段
１６ 定反力型防舷材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mooring system for a floating bridge in which a bridge bridged to a coastal area, a river, a lake, or the like has a foundation of a bridge pier located in the middle of the bridge as a buoyant body.
[0002]
[Prior art]
A floating bridge is composed of an upper structure that supports the bridge surface for passing vehicles and people, a buoyant body that supports the upper structure, and a mooring device that anchors them. There are many advantages, such as being able to reduce the ground reaction force at both ends of the bridge, or flexibly responding to land subsidence at both ends of the bridge.
[0003]
[Problems to be solved by the invention]
However, floating type bridges have the disadvantage that they are shaken due to fluctuations in tide level or the influence of wind or waves because buoyant bodies are used as the foundation of the pier part in the middle of the bridge.
[0004]
In addition, when used as a road bridge, usability as a road is required, and it is necessary to keep the displacement of the bridge within an allowable value during operation (usually about 20 m / sec or less).
[0005]
The present invention has been made to solve the above-mentioned drawbacks and the like. The purpose of the present invention is to keep the displacement of the bridge within an allowable value when used as a road bridge, while in a storm or a large amount. The purpose of this project is to provide a mooring system for floating bridges that allows the displacement of the bridge during an earthquake and measures the divergence of external forces acting on the bridge.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is configured as follows.
[0007]
(1) A floating bridge comprising a plurality of superstructures constituting a bridge surface, one or more buoyant bodies that support the superstructures, and a mooring device for mooring the superstructures. It is fixed to the ground by an installed constant reaction force type fender and a mooring line connected in series to the constant reaction type fender, and the upper structures are rotated at least about the vertical axis. Elastically restraining means for pivotally supporting the pivoting means having a vertical axis and storing rotational energy around the vertical axis of the upper structure at a predetermined interval on both sides of the pivoting means to return the upper structure to the initial position. A mooring system for floating bridges, characterized by installation.
[0008]
(2) The floating bridge mooring system according to (1), wherein the upper structures at both ends of the bridge are pivotally supported on the abutment by a pivoting device having at least a degree of freedom of rotation about the vertical axis.
[0009]
(3) The floating bridge according to (2), characterized in that the pivoting device has a degree of freedom to allow movement of the superstructure in the direction of the bridge axis in addition to the degree of freedom of rotation about the vertical axis. Mooring system.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a floating road bridge composed of a simple girder triple superstructure and two buoyant bodies will be described as an example.
[0011]
1 and 2, reference numeral 1 denotes a floating road bridge. The floating road bridge 1 is composed of an upper structure 2 composed of three simple girders 2 a, 2 b, 2 c, and two buoyancy bodies 3. The buoyancy body 3 is fixed to the ground 5 by a mooring line 4 such as a cable or a chain connected in series to a constant reaction type fender described later. In the figure, 6 indicates an anchor block.
[0012]
The central girder 2a located at the center of the upper structure 2 is fixed between the two buoyancy bodies 3 and 3, and the buffer girder 2b, 2c installed on both sides of the central girder 2a has one end on the central girder 2a. The other end is supported on the abutment 7.
[0013]
As shown in FIG. 3, between the central beam 2a and the buffer beams 2b and 2c, third and fourth types of support devices 8 and 9 are installed. The fourth support device 9 is installed on both sides of the third support device 8 at equal intervals.
[0014]
As shown in FIGS. 5 (a) and 5 (b), the third support device (type 3) 8 installed at the center of the center beam 2a has a male part 8a and a female part 8b via a universal joint 8c. Are displaced by the female portion 8b in the direction of the bridge axis (X axis) of the male portion 8a, the axis (Y axis) direction orthogonal to the bridge axis (hereinafter referred to as the bridge straight direction), and the vertical axis (Z axis). While the negative reaction force in the direction is constrained, the rotation of the male part 8a around the bridge axis (X axis), straight bridge (Y axis), vertical axis (Z axis), and positive / negative in the vertical axis (Z axis) direction Forces are allowed (see “Table 1”). The female portion 8b is fixed to the upper surface of the central portion of the central beam 2a, and the male portion 8a is fixed to the lower surface of the central portion of the buffer beams 2b and 2c.
[0015]
[Table 1]

[0016]
As shown in FIGS. 6 (a) and 6 (b), a fourth support device (type 4) 9 installed on both the left and right sides of the third support device is formed by alternately stacking rubber plates and metal plates in multiple stages. The lower part of the elastic restraint body 9a is fixed on the bottom surface of the non-covered container 9b, and a hinge 9c is attached to the upper part of the elastic restraint body 9a. The pin 9d of the hinge 9c is directed in the direction of the bridge (Y axis) and has the functions described in “Table 1”. Further, the lidless container 9b is fixed to the upper surfaces of both sides of the central beam 2a, and the free ends of the hinges 9c are fixed to the lower surfaces of both sides of the buffer beams 2b and 2c.
[0017]
As shown in FIG. 4, between the abutment 7 and the buffer girders 2b and 2c, two types of first and second support devices 10 and 11 are installed. The second support device 11 is installed at equal intervals on both sides of the first support device 10.
[0018]
As shown in FIGS. 7 (a) and 7 (b), the first support device (type 1) 10 installed at the center of the abutment 7 includes a saddle-shaped female portion 10a and the longitudinal length (X axis) of the female portion 10a. ), And a male part 10b, which has a shaft part 10c with a flange, a wheel 10d rotatably attached to the shaft part 10c, and a cross section fixed to the left and right sides of the flange 10e. The sliding portion 10f is configured to slide along a longitudinal groove 10g provided inside the female portion 10a. A rail 10h on which the male wheel 10d rolls is provided on the groove side wall surface of the female portion 10a.
[0019]
In the first support device 10, the displacement of the male portion 10b in the straight (Y-axis) direction is restricted by the female portion 10a and the negative reaction force in the vertical (Z-axis) direction is restricted, but the male portion 10b. Rotation around the bridge axis (X-axis), straight (Y-axis) and vertical axis (Z-axis), and positive / reverse force in the vertical (Z-axis) direction are allowed ("Table 1") reference). Moreover, the female part 10a is fixed to the center upper surface of the abutment 7, and the male part 10b is fixed to the lower center of the girders of the buffer girders 2b and 2c.
[0020]
As shown in FIGS. 8A and 8B, the second support device (type 2) 11 installed on the left and right sides of the first support device 10 mainly includes a concave rail 11a and the rail 11a. The universal joint 11b is movable in the longitudinal (X-axis) direction. In addition, in order to move the universal joint 11b smoothly, a rectangular slide plate 11d is fixed to the lower portion of the male portion 11c of the universal joint 11b, and elongated holding plates 11e are attached to the left and right sides of the concave rail 11a. . Further, the lateral width of the slide plate 11d is slightly narrower than the groove width of the concave rail 11a, and is slightly movable in the direction of the bridge (Y axis).
[0021]
The second support device 11 is restrained from the positive reaction force in the vertical axis (Z-axis) direction, but the displacement of the male part 11c in the bridge axis (X-axis) and straight (Y-axis) directions, and the bridge axis. (X axis), straight bridge (Y axis), rotation around the vertical axis (Z axis), and negative reaction force in the vertical axis (Z axis) direction are allowed (see “Table 1”). . The female portion 11f of the universal joint 11b is fixed to the lower surfaces of both sides of the buffer girders 2b and 2c, and the concave rail 11a is fixed to the upper surface of the abutment 7 facing the female portion 11f of the universal joint 11b.
[0022]
As shown in FIGS. 9 and 10, the constant reaction force type fender 12 mainly includes a main body 13 fixed obliquely downward on the buoyant body 3 and a predetermined range in the longitudinal direction of the main body 13. A movable portion 14 of a rectangular tube type that is movably attached only, two hydraulic jacks 15 that support the movable portion 14, and a constant reaction force type fender 16 attached to the tip of the movable portion 14. The mooring cable 4 is attached to the bracket 18 of the top plate 17 attached to the tip of the constant reaction force type fender 16. Further, stoppers 19 are attached to both the upper and lower sides of the center of the tip of the movable portion 14, and a plurality of sag prevention chains 20 are bridged between the tip of the movable portion 14 and the top plate 17. In the figure, 21 indicates a cover.
[0023]
Next, the operation of the mooring system will be described.
During use as a road bridge (usually at a wind speed of about 20 m / sec or less), horizontal external force in the direction of the bridge axis (X axis) is resisted by the mooring cable 4 and the reaction force type fender 16 connected in series. .
[0024]
On the other hand, when the floating road bridge 1 receives a horizontal force F from the direction of the bridge (Y axis), as shown in FIG. 11, two pieces installed at a predetermined distance in the direction of the bridge (Y axis) In the elastic restraint body 9a of the third support device 9, a reaction force ρ ′ is generated due to the rotation ρ around the vertical axis (Z axis) 8 due to the horizontal displacement e of the buoyancy body 3 in the direction perpendicular to the bridge (Y axis). The rotational reaction about the vertical axis (Z axis) 8 is suppressed by the couple reaction force ρ ′.
[0025]
That is, the superstructure 2 is rotated around the vertical axis (Z axis) 8 by the shear springs of the elastic restraining bodies 9a of the two third support members 9 separated by a predetermined distance in the direction of the bridge (Y axis). Will be elastically restrained.
[0026]
In case of a storm or a large earthquake, a constant reaction type fender 16 installed on the buoyant body 3, a mooring line 4 connected in series to the constant reaction type fender 16 and a central girder The elastic restraint body 9a installed at the connecting portion between 2a and the buffer girders 2b and 2c is displaced to diverge the external force acting on the floating road bridge 1.
[0027]
In the above description, the superstructure of a simple girder three series and the floating road bridge composed of two buoyant bodies have been described as an example. However, the present invention provides a superstructure composed of a plurality of simple girder and one box. The present invention can be widely applied to floating structures provided with the above buoyancy bodies.
[0028]
In addition, since the mooring cable 4 uses a cable, a chain, or the like as described above, the mooring cable 4 has advantages such as little change in characteristics due to ground fluctuation, restoration characteristics, and prevention of excessive displacement. Further, in terms of maintenance, there is an advantage that the length can be adjusted using a shim or the like to manage the characteristics. Moreover, as an overall characteristic, there is an advantage that a long period can be measured and a seismic force can be reduced.
[0029]
Further, the fourth support device 9 acts as a rotational elastic spring by couple force, and can adjust the natural period and thereby control the displacement by adjusting the rigidity of the elastic restraint 9a. Moreover, since the rotation with respect to the axis perpendicular to the bridge axis is free, the superstructure 2 has an advantage that stress due to the influence of ground deformation does not occur.
[0030]
Moreover, the constant reaction force type fender 16 absorbs energy and thus has a seismic isolation function. It also has a knock-off function, that is, a trigger function. In addition, as an overall function, it has the advantage that the period can be increased and the seismic force can be reduced.
[0031]
As described above, when the mooring cable 4 and the constant reaction force type fender 16 are coupled in series, the advantages of the mooring line 4 and the constant reaction force type fender 16 are added, and the reusability improves usability as a road bridge. In addition, having constant reaction force improves the response to shock loads and improves the load resistance.
[0032]
By adding a fourth support device 9 as an elastic restraint to the mooring cable 4 and the constant reaction force type fender 16, the displacement of the upper structure 2 in the direction perpendicular to the bridge axis can be controlled, and the linear alignment The amount of fluctuation can be reduced, thus improving the usability as a road bridge.
[0033]
In addition, it is possible to adjust the natural period of the bridge straight direction movement. As a result, it has a constant reaction force, so that the natural period can be removed from the dominant period of earthquakes and waves, and the load resistance is improved.
[0034]
【The invention's effect】
As described above, the present invention provides a floating bridge comprising a plurality of superstructures constituting a bridge surface, one or more buoyant bodies that support the superstructures, and a mooring device that anchors the superstructures. Is fixed to the ground by a constant reaction type fender installed on the buoyancy body and a mooring line connected in series to the constant reaction type fender, and the upper structures are at least vertically Since it is pivotally supported by pivot means having a degree of freedom of rotation around the axis, and a restraining means for restraining rotation of the upper structure around the vertical axis is provided on both sides of the pivot means at a predetermined interval. When used as a bridge, the displacement of the bridge can be kept within the allowable value.
[0035]
On the other hand, during storms and large earthquakes, the bridge can be displaced to some extent and the external force acting on the bridge can be diverged, thus avoiding damage to the bridge.
[Brief description of the drawings]
FIG. 1 is a side view of a floating bridge to which a mooring system of the present invention is applied.
FIG. 2 is a plan view of the floating bridge of FIG.
3 is a cross-sectional view taken along the line AA ′ of FIG.
4 is a cross-sectional view taken along the line BB ′ of FIG.
5A is a front view including a partial cross section of the third support device, and FIG. 5B is a side view including a partial cross section of the third support device.
6A is a front view including a partial cross section of a fourth support device, and FIG. 6B is a side view including a partial cross section of the fourth support device.
7A is a side view including a cross section of the first support device, and FIG. 7B is a side view including a partial cross section of the first support device.
8A is a front view including a partial cross section of the second support device, and FIG. 8B is a side view including a partial cross section of the second support device.
FIG. 9 is a plan view of a constant reaction force type fender.
FIG. 10 is a cross-sectional view taken along the line CC ′ of FIG.
FIG. 11 is an operation explanatory diagram of a floating bridge mooring system according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Floating type bridge 2 Superstructure 3 Buoyant body 4 Mooring line 5 Ground 8 Pivoting means 9 Restraint means 16 Constant reaction type fender

Claims (3)

In a floating bridge comprising a plurality of superstructures constituting a bridge surface, one or more buoyancy bodies supporting the superstructures, and a mooring device for mooring them, the buoyancy bodies are installed on the buoyancy bodies. A pivot that has a reaction force type fender and a mooring line connected in series to the constant reaction type fender and is fixed to the ground, and the upper structures are at least pivotal about a vertical axis. In addition to being pivotally supported by the supporting means, elastic restraining means for storing rotational energy around the vertical axis of the upper structure and returning the upper structure to the initial position at predetermined intervals on both sides of the pivoting means is installed. A mooring system for floating bridges. The mooring system for a floating bridge according to claim 1, wherein the upper structures at both ends of the bridge are pivotally supported on the abutment by a pivoting device having at least a degree of freedom of rotation about the vertical axis. 3. The floating bridge mooring system according to claim 2, wherein the pivoting device has a degree of freedom of movement allowing the movement of the superstructure in the direction of the bridge axis in addition to the degree of freedom of rotation about the vertical axis. .

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