JP6055588B2 - Portal ramen bridge with improved vertical load dispersion - Google Patents

Portal ramen bridge with improved vertical load dispersion Download PDF

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JP6055588B2
JP6055588B2 JP2011106354A JP2011106354A JP6055588B2 JP 6055588 B2 JP6055588 B2 JP 6055588B2 JP 2011106354 A JP2011106354 A JP 2011106354A JP 2011106354 A JP2011106354 A JP 2011106354A JP 6055588 B2 JP6055588 B2 JP 6055588B2
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abutment
ramen bridge
ground
portal ramen
vertical load
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JP2012237127A (en
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鈴木　巧
巧 鈴木
泰久 阿山
泰久 阿山
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Obayashi Corp
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Description

本発明は、鉛直荷重の分散性を高めたポータル（門型）ラーメン橋に関する。   The present invention relates to a portal (gate type) ramen bridge with improved vertical load dispersibility.

図１３（ａ）に示すように、単純支持構造の桁橋（単純桁橋）１００では、支承１０１を有する一対の橋台１０２により、上部構造である主桁１０３の両端を支持し、支承１０１の滑り作用によって主桁１０３の変形を吸収している。また、単純桁橋１００では、荷重の大きさや地震等の要因によって橋台１０２も変形する。ここで、橋台１０２には橋の中央側に向けて土圧が加わっており、これに対抗するために大型のフーチング１０４を備えている。そして、この大型のフーチング１０４により、地盤Ｇの支持力も大きなものとなっている。   As shown in FIG. 13 (a), in a simple support structure girder (simple girder bridge) 100, both ends of a main girder 103 as an upper structure are supported by a pair of abutments 102 having a support 101. The deformation of the main beam 103 is absorbed by the sliding action. Further, in the simple girder bridge 100, the abutment 102 is also deformed due to factors such as the magnitude of the load and an earthquake. Here, earth pressure is applied to the abutment 102 toward the center of the bridge, and a large footing 104 is provided to counter this. The large footing 104 also increases the support force of the ground G.

一方、図１３（ｂ）に示すように、橋台１１１と主桁１１２とを剛結合したポータルラーメン橋１１０の構造形式もある。ポータルラーメン橋１１０とすることにより、一対の橋台１１１が主桁１１２を介して一体化されるため、橋桁と橋台の取り合い部の構造を単純化でき、橋全体の剛性を高めることができるとともに、橋台１１１の変形を抑制できるので、橋台１１１の変形防止の目的では大型のフーチングが不要となる。しかし、このようなポータルラーメン橋１１０では、鉛直荷重が各橋台１１１の底部に集中することになり、長期間に亘る使用によって橋台１１１の過度な沈下が生じるおそれがある。   On the other hand, as shown in FIG. 13B, there is also a structural form of a portal ramen bridge 110 in which an abutment 111 and a main girder 112 are rigidly connected. By using the portal ramen bridge 110, the pair of abutments 111 are integrated via the main girder 112. Therefore, the structure of the connecting portion between the bridge girder and the abutment can be simplified, and the rigidity of the entire bridge can be increased. Since the deformation of the abutment 111 can be suppressed, a large footing is not necessary for the purpose of preventing the deformation of the abutment 111. However, in such a portal ramen bridge 110, a vertical load will concentrate on the bottom part of each abutment 111, and there is a possibility that excessive settlement of the abutment 111 occurs due to use over a long period of time.

橋台１１１の過度な沈下を抑えるためには、図１３（ｃ）に示すように、各橋台１１１の底部に基礎杭１１３を埋設したりすることが一般的である（特許文献１を参照）。   In order to suppress excessive settlement of the abutment 111, it is common to embed a foundation pile 113 at the bottom of each abutment 111 as shown in FIG. 13 (c) (see Patent Document 1).

特開２００７−３２１４５２号公報JP 2007-321452 A

しかしながら、各橋台１１１の底部に基礎杭１１３を埋設したりすることは、その分だけラーメン橋１１０の全体構造が複雑になるので好ましくない。   However, it is not preferable to bury the foundation pile 113 at the bottom of each abutment 111 because the entire structure of the ramen bridge 110 becomes complicated accordingly.

本発明は、このような事情に鑑みてなされたものであり、その目的は、ポータルラーメン橋の全体構造を簡素化しつつ鉛直荷重を分散させ、橋台の過度な沈下を抑制することにある。   This invention is made | formed in view of such a situation, The objective is to disperse | distribute a vertical load, suppressing the excessive settlement of an abutment, simplifying the whole structure of a portal ramen bridge.

上記目的を達成するため、本発明は、一対の橋台と主桁とを備え、前記一対の橋台と前記主桁とを剛結合したポータルラーメン橋であって、一方の橋台は、他方の橋台とは反対側に位置する外側表面が、上方に向かう程に前記他方の橋台から離れる方向へ傾いていることを特徴とする。   In order to achieve the above object, the present invention is a portal ramen bridge comprising a pair of abutments and a main girder, wherein the pair of abutments and the main girder are rigidly connected, and one abutment and the other abutment The outer surface located on the opposite side is inclined in a direction away from the other abutment as it goes upward.

本発明によれば、橋台の外側表面がオーバーハングするように傾斜しているので、この傾斜面によって鉛直荷重を地盤や盛土に分散させることができる。これにより、基礎杭を埋設する等の対策が必要なくなり、全体構造を簡素化しつつ鉛直荷重を分散させることができ、橋台の過度な沈下を抑制できる。   According to the present invention, since the outer surface of the abutment is inclined so as to overhang, the vertical load can be distributed to the ground and the embankment by the inclined surface. Thereby, measures, such as burying a foundation pile, become unnecessary, a vertical load can be disperse | distributing, simplifying the whole structure, and the excessive settlement of an abutment can be suppressed.

また、本発明に係るポータルラーメン橋において、前記橋台の外側表面に沿って補強盛土を設けた場合には、補強盛土によって地盤を自立させることにより、橋台構築の際の地盤側型枠設置作業を省力化することができる。   Further, in the portal ramen bridge according to the present invention, when a reinforced embankment is provided along the outer surface of the abutment, the ground side formwork installation work at the time of abutment construction can be performed by making the ground self-supported by the reinforced embankment. It can save labor.

また、本発明に係るポータルラーメン橋において、前記橋台の外側表面に近い側の端部が階段状となるように積層することで、前記補強盛土が設けられ、前記橋台の平坦な傾斜面と前記補強盛土の階段状の端部との間の隙間に三角柱状のスペーサを設けた場合には、橋台からの鉛直荷重を効果的に地盤へ伝達することができる。 Further, in the portal ramen bridge according to the present invention, the reinforcing embankment is provided by laminating the end portion on the side close to the outer surface of the abutment so as to have a stepped shape, and the flat inclined surface of the abutment and the When a triangular prism spacer is provided in the gap between the staircase ends of the reinforced embankment, the vertical load from the abutment can be effectively transmitted to the ground.

また、本発明に係るポータルラーメン橋において、前記橋台の外側表面における傾斜角度を、前記橋台に作用する鉛直荷重を受ける地盤の面積と、前記地盤における鉛直荷重の分散角度に基づいて定めるようにした場合には、橋台に作用する鉛直荷重を地盤で確実に支持できる。 Further, the portal rigid frame bridge according to the present invention, the inclination angle in the outer surface of the abutment, and the area of ground which receives the vertical load acting on the bridge abutment, as determined based on the angular spread of the vertical load before Symbol Ground In this case, the vertical load acting on the abutment can be reliably supported by the ground.

本発明によれば、ポータルラーメン橋において、全体構造を簡素化しつつ鉛直荷重を分散させることができ、橋台の過度な沈下を抑制できる。   ADVANTAGE OF THE INVENTION According to this invention, in a portal ramen bridge, a vertical load can be disperse | distributed, simplifying the whole structure, and the excessive settlement of an abutment can be suppressed.

ポータルラーメン橋の概略を説明する図である。It is a figure explaining the outline of a portal ramen bridge. 左側橋台と地盤との境界部分を示す部分拡大図である。It is the elements on larger scale which show the boundary part of a left side abutment and the ground. ポータルラーメン橋の具体例を説明する図である。It is a figure explaining the specific example of a portal ramen bridge. 橋台と改良盛土を説明する部分拡大図である。It is the elements on larger scale explaining an abutment and improved embankment. 図３に示すラーメン橋の構築手順を説明する図であり、地盤Ｇを掘削した状態を示す。It is a figure explaining the construction procedure of the ramen bridge shown in Drawing 3, and shows the state where ground G was excavated. 同じく構築の説明図であり、最下層の締固め層を設けた状態を示す。It is explanatory drawing of construction similarly and shows the state which provided the lowermost compaction layer. 同じく構築の説明図であり、２層目の締固め層を設けた状態を示す。It is explanatory drawing of construction similarly and shows the state which provided the 2nd compaction layer. 同じく構築の説明図であり、全ての締固め層を設けた状態を示す。It is explanatory drawing of construction similarly and shows the state which provided all the compaction layers. 同じく構築の説明図であり、橋台を構築した状態を示す。It is explanatory drawing of construction similarly and shows the state where the abutment was constructed. 同じく構築の説明図であり、主桁を構築した状態を示す。It is explanatory drawing of construction similarly and shows the state which constructed the main girder. 変形例を説明する図であり、（ａ）は地盤と橋台との空間を途中まで埋め戻した状態を示し、（ｂ）は地盤と橋台との空間を全部埋め戻した状態を示す。It is a figure explaining a modification, (a) shows the state which backfilled the space of a ground and an abutment to the middle, (b) shows the state which backfilled all the space of a ground and an abutment. 他の変形例を説明する図であり、（ａ）はポータルラーメン橋の片側半部と補強盛土とを示し、（ｂ）は橋台の外側表面近傍を拡大して示す。It is a figure explaining another modification, (a) shows one half of a portal ramen bridge and reinforcement embankment, and (b) expands and shows the outside surface neighborhood of an abutment. 従来技術を説明する図であり、（ａ）は単純桁橋を示し、（ｂ）はポータルラーメン橋を示し、（ｃ）は基礎杭の上に構築されたポータルラーメン橋を示す。It is a figure explaining a prior art, (a) shows a simple girder bridge, (b) shows a portal ramen bridge, (c) shows the portal ramen bridge constructed | assembled on the foundation pile.

以下、本発明の実施の形態について説明する。まず、図１を参照して本発明におけるポータルラーメン橋１０の概略について説明する。   Embodiments of the present invention will be described below. First, the outline of the portal ramen bridge 10 in the present invention will be described with reference to FIG.

図１に示すポータルラーメン橋１０は、左右一対の橋台１１，１２と、これら橋台１１，１２同士の間に架け渡される主桁１３とを有している。そして、主桁１３と各橋台１１，１２とが剛結合されて門型になっている。便宜上、以下の説明では、図中左側に位置する橋台を左側橋台１１といい、図中右側に位置する橋台を右側橋台１２という。また、主桁１３における左側橋台１１と右側橋台１２との中間位置を橋の中央とし、左側橋台１１及び右側橋台１２から見て橋の中央側を内側といい、反対側を外側という。   The portal ramen bridge 10 shown in FIG. 1 has a pair of left and right abutments 11 and 12 and a main girder 13 bridged between the abutments 11 and 12. The main girder 13 and the abutments 11 and 12 are rigidly connected to form a gate shape. For convenience, in the following description, the abutment located on the left side in the figure is referred to as the left side abutment 11, and the abutment located on the right side in the figure is referred to as the right side abutment 12. Further, an intermediate position between the left abutment 11 and the right abutment 12 in the main girder 13 is defined as the center of the bridge, and the center side of the bridge as viewed from the left abutment 11 and the right abutment 12 is referred to as the inside, and the opposite side is referred to as the outside.

図１３（ｂ）との対比から判るように、図１のポータルラーメン橋１０では、左側橋台１１の外側表面（すなわち左側部）１１ａ、及び、右側橋台１２の外側表面（すなわち右側部）１２ａが、それぞれ外側に向かってオーバーハングされ、ポータルラーメン橋１０の全体が地盤Ｇに対して楔状に構成されている点に特徴を有している。すなわち、左側橋台１１の外側表面１１ａは、上方に向かう程に左側へ向けて張り出すように傾斜（つまり右側橋台１２から離れる方向へ傾斜）されている。同様に、右側橋台１２の外側表面１２ａは、上方に向かう程に右側へ向けて張り出すように傾斜（つまり左側橋台１１から離れる方向へ傾斜）されている。   As can be seen from the comparison with FIG. 13B, in the portal ramen bridge 10 of FIG. 1, the outer surface (that is, the left side portion) 11 a of the left abutment 11 and the outer surface (that is, the right side portion) 12 a of the right abutment 12 are Each of the portal ramen bridges 10 is characterized in that the entire portal ramen bridge 10 is formed in a wedge shape with respect to the ground G. That is, the outer surface 11a of the left abutment 11 is inclined so as to protrude toward the left side as it goes upward (that is, incline away from the right abutment 12). Similarly, the outer surface 12a of the right abutment 12 is inclined so as to protrude toward the right side as it goes upward (that is, incline away from the left abutment 11).

このように、左側橋台１１及び右側橋台１２の各外側表面１１ａ，１２ａを傾斜面とすることにより、各外側表面１１ａ，１２ａの全体で鉛直荷重を地盤Ｇに伝えることができる。例えば、図２に示すように、外側表面１１ａにおける或る点Ｐに作用した鉛直荷重は、荷重の分散角度θ１で拡がりながら地盤Ｇ内を伝わっていく。すなわち、傾斜した外側表面１１ａ，１２ａによって、各橋台１１，１２に加わる鉛直荷重を広範囲に分散させて地盤Ｇに伝えることができる。これにより、基礎杭を埋設する等の対策が必要なくなり、全体構造を簡素化しつつも各橋台１１，１２の過度な沈下を抑制できる。   As described above, the outer surfaces 11a and 12a of the left abutment 11 and the right abutment 12 are inclined surfaces, whereby a vertical load can be transmitted to the ground G on the entire outer surfaces 11a and 12a. For example, as shown in FIG. 2, a vertical load applied to a certain point P on the outer surface 11a propagates through the ground G while spreading at a load dispersion angle θ1. That is, the inclined outer surfaces 11a and 12a can distribute the vertical load applied to each abutment 11 and 12 to the ground G in a wide range. Thereby, measures, such as embedding a foundation pile, become unnecessary, and the excessive settlement of each abutment 11 and 12 can be suppressed, simplifying the whole structure.

なお、一般的な砂質地盤における分散角度θ１は約３０度である。そして、硬い地盤であれば分散角度θ１は３０度よりも小さくなり、反対に軟弱な地盤であれば分散角度θ１は３０度よりも大きくなる。   In addition, dispersion angle (theta) 1 in a general sandy ground is about 30 degree | times. If the ground is hard, the dispersion angle θ1 is smaller than 30 degrees. Conversely, if the ground is soft, the dispersion angle θ1 is larger than 30 degrees.

ここで、各橋台１１，１２における外側表面１１ａ，１２ａの傾斜角度について説明する。以下の説明は左側橋台１１についてのものであるが、右側橋台１２についても同様にあてはまる。   Here, the inclination angle of the outer surfaces 11a and 12a in the respective abutments 11 and 12 will be described. The following description is for the left abutment 11, but the same applies to the right abutment 12.

図１に示すように、左側橋台１１に作用する鉛直荷重は、符号Ｂで示す面積の地盤Ｇで受けることになる。具体的には、左側橋台１１の右下端（内側下端点）Ａ１を始点に水平方向へ引いた仮想線Ｘ１と、左側橋台１１の左上端（外側上端点）Ａ２を始点に分散角度θ１で左斜め下方に向けて引いた仮想線Ｘ２とが交差する交点Ａ３を定めたとき、点Ａ１から点Ａ３までの距離Ｌにポータルラーメン橋１０の幅（紙面奥行方向の寸法）を乗じて得られる面積Ｂの地盤Ｇが、左側橋台１１に作用する鉛直荷重を受けることになる。   As shown in FIG. 1, the vertical load acting on the left abutment 11 is received by the ground G having the area indicated by the symbol B. Specifically, an imaginary line X1 drawn horizontally from the lower right end (inner lower end point) A1 of the left abutment 11 and the left upper end (outer upper end point) A2 of the left abutment 11 to the left with a dispersion angle θ1. The area obtained by multiplying the distance L from the point A1 to the point A3 by the width of the portal ramen bridge 10 (the dimension in the depth direction on the paper) when the intersection A3 intersecting with the virtual line X2 drawn obliquely downward is defined. The ground G of B receives a vertical load acting on the left abutment 11.

面積Ｂで受ける荷重は等分布ではないが、この面積Ｂが大きくなる程、分布荷重の最大値は小さくなる。そして、分布荷重の最大値が地盤許容支持力度よりも小さければ、面積Ｂの地盤Ｇによって左側橋台１１を支持できる。このことから、左側橋台１１の外側表面１１ａにおける傾斜角度θ２は、左側橋台１１に作用する鉛直荷重を受ける地盤Ｇの面積Ｂと、地盤Ｇにおける鉛直荷重の分散角度θ１および荷重条件に基づいて定められることが判る。例えば、分布荷重の最大値が地盤許容支持力度よりも小さくなるように面積Ｂを定め、この面積Ｂから各点Ａ２，Ａ３を求める。また、点Ａ１から左側橋台１１における底面の分だけ外側の位置に点Ａ１´を定める。この場合、点Ａ１´と点Ａ２とを結ぶ仮想線Ｘ３の角度が、外側表面１１ａの傾斜角度θ２に相当する。 The load received in the area B is not evenly distributed, but the maximum value of the distributed load decreases as the area B increases. If the maximum value of the distributed load is smaller than the ground allowable bearing force, the left abutment 11 can be supported by the ground G having the area B. Therefore, the inclination angle θ2 in the outer surface 11a of the left abutment 11, and the area B of the ground G which receives the vertical load acting on the left abutment 11, based on the dispersion angle θ1 and loading conditions the vertical loads in the ground plate G It turns out that it is decided. For example, the area B is determined so that the maximum value of the distributed load is smaller than the ground allowable bearing force, and the points A2 and A3 are obtained from the area B. Further, a point A1 ′ is determined at a position outside the point A1 by the amount of the bottom surface of the left abutment 11. In this case, the angle of the imaginary line X3 connecting the point A1 ′ and the point A2 corresponds to the inclination angle θ2 of the outer surface 11a.

次に、ポータルラーメン橋の具体例について説明する。   Next, a specific example of the portal ramen bridge will be described.

図３に示す具体例のポータルラーメン橋２０もまた、左側橋台２１と、右側橋台２２と、主桁２３とを有しており、主桁２３と各橋台２１，２２とが剛結合されて門型になっている。図４に拡大して示すように、左側橋台２１の外側表面２１ａは、階段状傾斜面によって構成されている。すなわち、この外側表面２１ａは、上下方向に交互に並ぶ垂直面２１ｂと水平面２１ｃによって構成され、全体として傾斜面を構成している。なお、図３に示すように、右側橋台２２の外側表面２２ａについても同様に、垂直面２２ｂ及び水平面２２ｃを有する階段状傾斜面によって構成されている。   3 also includes a left abutment 21, a right abutment 22, and a main girder 23. The main girder 23 and each abutment 21, 22 are rigidly connected to each other. It is a type. As shown in an enlarged view in FIG. 4, the outer surface 21 a of the left abutment 21 is constituted by a stepped inclined surface. That is, the outer surface 21a is composed of vertical surfaces 21b and horizontal surfaces 21c that are alternately arranged in the vertical direction, and forms an inclined surface as a whole. As shown in FIG. 3, the outer surface 22a of the right abutment 22 is similarly configured by a stepped inclined surface having a vertical surface 22b and a horizontal surface 22c.

左側橋台２１の外側（左側）及び右側橋台２２の外側（右側）には、それぞれ補強盛土３０が設けられている。この補強盛土３０は、各橋台２１，２２に近い側の端部表面が補強シート３１で覆われた締固め層３２を、各端部が階段状となるように積層することで設けられている。そして、階段状傾斜面とされた左側橋台２１及び右側橋台２２の外側表面２１ａ，２２ａは、それぞれ、補強盛土３０の階段状端部に嵌っている。すなわち、各橋台２１，２２に接する補強盛土３０は、階段状傾斜面を構成する垂直面２１ｂ及び水平面２１ｃと隙間なく接している。   Reinforcing embankments 30 are provided on the outside (left side) of the left abutment 21 and on the outside (right side) of the right abutment 22, respectively. The reinforcing embankment 30 is provided by laminating a compaction layer 32 in which end surfaces near the abutments 21 and 22 are covered with a reinforcing sheet 31 so that each end portion is stepped. . And the outer surface 21a, 22a of the left side abutment 21 and the right side abutment 22 made into the step-like inclined surface is fitted in the step-like edge part of the reinforcement embankment 30, respectively. That is, the reinforcing embankment 30 in contact with the abutments 21 and 22 is in contact with the vertical surface 21b and the horizontal surface 21c constituting the step-like inclined surface without a gap.

このポータルラーメン橋２０では、各橋台２１，２２の外側表面２１ａ，２２ａに沿って補強盛土３０が設けられているので、各橋台２１，２２に対する支持力を高めることができる。また、各外側表面２１ａ，２２ａが階段状傾斜面で構成され、補強盛土３０の階段状端部に嵌っている。このため、鉛直荷重を分散できるとともに、各外側表面２１ａ，２２ａと補強盛土３０との間で生じる滑りを抑制できる。すなわち、鉛直荷重は、階段状傾斜面の各水平面２１ｃを下方向に押し下げる力となるので、各橋台２１，２２からの鉛直荷重を効果的に地盤Ｇへ伝達できるし、滑りを抑制しつつ荷重を分散できる。また、各水平面２１ｃが上下方向に位置をずらして設けられているので、水平方向だけでなく、垂直方向にも荷重を分散させることができる。   In the portal ramen bridge 20, the reinforcing embankment 30 is provided along the outer surfaces 21 a and 22 a of the abutments 21 and 22, so that the support force for the abutments 21 and 22 can be increased. Moreover, each outer surface 21a and 22a is comprised by the step-like inclined surface, and is fitted in the step-like edge part of the reinforced embankment 30. As shown in FIG. For this reason, while being able to disperse | distribute a vertical load, the slip produced between each outer surface 21a, 22a and the reinforcement embankment 30 can be suppressed. That is, the vertical load is a force that pushes down each horizontal surface 21c of the stepped inclined surface downward, so that the vertical load from each abutment 21, 22 can be effectively transmitted to the ground G, and the load is suppressed while preventing slippage. Can be distributed. Further, since the horizontal planes 21c are provided with their positions shifted in the vertical direction, the load can be dispersed not only in the horizontal direction but also in the vertical direction.

なお、図１で説明したポータルラーメン橋１０と比較した場合、鉛直荷重の分散が点Ｐで行われるか、水平面２１ｃ，２２ｃで行われるかの違いはあるが、分散角度θ１で鉛直荷重が分散されている点については同じである。このため、各外側表面２１ａ，２２ａの傾斜角度も、前述したように、面積Ｂ（図１参照）の地盤Ｇの大きさに基づいて定めることができる。   Compared with the portal ramen bridge 10 described with reference to FIG. 1, there is a difference in whether the vertical load is distributed at the point P or the horizontal planes 21c and 22c, but the vertical load is distributed at the dispersion angle θ1. The same is true for the points. For this reason, the inclination angle of each outer surface 21a, 22a can also be determined based on the size of the ground G of the area B (see FIG. 1) as described above.

次に、具体例のポータルラーメン橋２０の構築手順について説明する。なお、以下の説明では、ポータルラーメン橋２０における左側半部の構築手順について説明するが、右側半部についても同様の手順で構築される。   Next, the construction procedure of the portal ramen bridge 20 as a specific example will be described. In the following description, a procedure for constructing the left half of the portal ramen bridge 20 will be described, but the right half is constructed in the same procedure.

この構築手順では、まず図５に示すように、左側橋台２１及び補強盛土３０が構築される範囲Ｙの地盤Ｇを掘削して除去する。地盤Ｇを除去したならば、図６に示すように、最下層の締固め層３２Ａを設ける。この締固め層３２Ａは、掘削で形成された法面Ｇａから左側橋台２１の構築予定位置まで一連に設けられる。また、締固め層３２Ａにおける左側橋台２１側の端部表面は、補強シート３１Ａで覆われている。この補強シート３１Ａは、締固め層３２Ａの端部が崩れないように保持するためのものであり、締固め層３２Ａの下面と端面と上面に沿ってコ字状に折り返されている。   In this construction procedure, first, as shown in FIG. 5, the ground G in the range Y in which the left abutment 21 and the reinforcing embankment 30 are constructed is excavated and removed. When the ground G is removed, a lowermost compaction layer 32A is provided as shown in FIG. This compaction layer 32A is provided in a series from the slope Ga formed by excavation to the planned construction position of the left abutment 21. Further, the end surface on the left abutment 21 side in the compaction layer 32A is covered with a reinforcing sheet 31A. The reinforcing sheet 31A is for holding the end portion of the compaction layer 32A so as not to collapse, and is folded back in a U shape along the lower surface, the end surface, and the upper surface of the compaction layer 32A.

最下層の締固め層３２Ａを設けたならば、２層目の締固め層３２Ｂを設ける。２層目の締固め層３２Ｂを設けるに際し、その端部は、最下層の締固め層３２Ａの端部よりも左側橋台２１から離れた位置に定められる。言い換えれば、階段状となるように各締固め層３２Ａ，３２Ｂの端部が位置をずらして設けられている。２層目の締固め層３２Ｂを設けることで、最下層の締固め層３２Ａの端部を覆う補強シート３１Ａが押圧状態で固定される。これにより、最下層の締固め層３２Ａについて端部の形状が保持され、自立する。また、２層目の締固め層３２Ｂを設けるに際しても、最下層の締固め層３２Ａと同様に、コ字状に折り返された補強シート３１Ｂが設けられる。   If the lowermost compaction layer 32A is provided, the second compaction layer 32B is provided. When the second compaction layer 32B is provided, the end thereof is determined at a position farther from the left abutment 21 than the end of the lowermost compaction layer 32A. In other words, the end portions of the compaction layers 32A and 32B are provided so as to be stepped so as to be stepped. By providing the second compaction layer 32B, the reinforcing sheet 31A covering the end of the lowermost compaction layer 32A is fixed in a pressed state. Thereby, the shape of the end of the lowermost compaction layer 32 </ b> A is maintained and is self-supporting. Further, when the second compaction layer 32B is provided, a reinforcing sheet 31B folded back in a U-shape is provided as in the lowermost compaction layer 32A.

以後は、同様の手順で締固め層３２を下層側から順に設ける。図８に示すように、最上層の締固め層３２Ｊ及び補強シート３１Ｊを設けることで、補強盛土３０が完成する。この補強盛土３０の端部は階段状傾斜面として構成され、補強シート３１Ａ〜３１Ｊによって自立状態で保持される。   Thereafter, the compaction layer 32 is provided in order from the lower layer side in the same procedure. As shown in FIG. 8, the reinforcement embankment 30 is completed by providing the uppermost compaction layer 32J and the reinforcement sheet 31J. The edge part of this reinforcement embankment 30 is comprised as a step-like inclined surface, and is hold | maintained in the self-supporting state by reinforcement sheet 31A-31J.

図９に示すように、補強盛土３０の完成後、左側橋台２１を構築する。左側橋台２１の構築は、例えば、型枠内に鉄筋を建て込み、コンクリートを打設することで行う。このとき、コンクリートは、補強シート３１の表面側に直接打設される。前述したように、補強盛土３０は自立しているので、コンクリートを打設する際の地盤側型枠の設置作業を省力化できる。また、コンクリートが補強シート３１の表面側に直接打設されるため、左側橋台２１の外側表面２１ａは、補強盛土３０の階段状傾斜面に倣った形状の階段状傾斜面として形成される。すなわち、左側橋台２１の階段状傾斜面２１ａと補強盛土３０の階段状傾斜面とが、隙間なく密着した状態で設けられる。   As shown in FIG. 9, the left abutment 21 is constructed after the reinforcement embankment 30 is completed. The left abutment 21 is constructed by, for example, building a reinforcing bar in a mold and placing concrete. At this time, the concrete is directly placed on the surface side of the reinforcing sheet 31. As described above, since the reinforcing embankment 30 is self-supporting, it is possible to save labor in installing the ground-side formwork when placing concrete. Further, since concrete is directly placed on the surface side of the reinforcing sheet 31, the outer surface 21 a of the left abutment 21 is formed as a stepped inclined surface having a shape following the stepped inclined surface of the reinforcing embankment 30. That is, the stepped inclined surface 21a of the left abutment 21 and the stepped inclined surface of the reinforcing embankment 30 are provided in close contact with each other without a gap.

図１０に示すように、左側橋台２１の構築後、主桁２３を構築する。主桁２３は、左側橋台２１と、この左側橋台２１と同様に構築された右側橋台２２との間に構築される。例えば、鉄筋を配筋し、型枠を設け、コンクリートを打設することで構築される。主桁２３の構築により、ポータルラーメン橋２０の構築が完了する。   As shown in FIG. 10, after the construction of the left abutment 21, the main girder 23 is constructed. The main girder 23 is constructed between the left abutment 21 and the right abutment 22 constructed in the same manner as the left abutment 21. For example, it is constructed by placing reinforcing bars, providing formwork, and placing concrete. With the construction of the main girder 23, construction of the portal ramen bridge 20 is completed.

以上の構築手順では、端部が補強シート３１Ａ〜３１Ｊによってコ字状に覆われた締固め層３２Ａ〜３２Ｊを、各端部が階段形状となるように積層することで補強盛土３０を構築し、補強盛土３０の端部にコンクリートを打設することで各橋台２１，２２を構築している。このため、各外側表面２１ａ，２２ａが補強盛土３０の階段状端部に嵌る階段状傾斜面とされた橋台１１，１２を容易に構築できる。   In the above construction procedure, the reinforced embankment 30 is constructed by laminating the compaction layers 32A to 32J whose ends are covered with the U-shaped reinforcement sheets 31A to 31J so that each end has a stepped shape. The abutments 21 and 22 are constructed by placing concrete at the end of the reinforcing embankment 30. For this reason, it is possible to easily construct the abutments 11 and 12 in which the outer surfaces 21 a and 22 a are stepped inclined surfaces that fit into the stepped ends of the reinforcing embankment 30.

以上の実施形態の説明は、本発明の理解を容易にするためのものであり、本発明を限定するものではない。本発明はその趣旨を逸脱することなく、変更、改良され得ると共に本発明にはその等価物が含まれる。例えば、次のように構成してもよい。   The above description of the embodiment is for facilitating the understanding of the present invention, and does not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof. For example, you may comprise as follows.

前述の実施形態では、階段状端部を有する補強盛土３０を設けた後に各橋台２１，２２を構築していたが、図１１（ａ），（ｂ）に示すポータルラーメン橋４０のように、掘削部分に予め橋台４１や主桁４２等を構築しておき、その後に掘削部分を土Ｚで埋め戻すようにしてもよい。   In the above-described embodiment, the abutments 21 and 22 are constructed after providing the reinforcing embankment 30 having stepped end portions, but like the portal ramen bridge 40 shown in FIGS. 11 (a) and 11 (b), The abutment 41, the main girder 42, etc. may be constructed in advance in the excavation part, and then the excavation part may be backfilled with soil Z.

また、各橋台の外側表面に関し、図３の外側表面２１ａ，２２ａのように階段状傾斜面にしてもよいし、図１１の外側表面４１ａのように、フラットな傾斜面にしてもよい。階段状傾斜面にすることで、橋台２１と地盤Ｇの間の滑りを抑制できる。また、平坦傾斜面にすることで、橋台４１の構築を容易に行うことができる。   Moreover, regarding the outer surface of each abutment, it may be a stepped inclined surface like the outer surfaces 21a and 22a of FIG. 3, or may be a flat inclined surface like the outer surface 41a of FIG. By using a step-like inclined surface, the slip between the abutment 21 and the ground G can be suppressed. Moreover, construction of the abutment 41 can be easily performed by using a flat inclined surface.

また、各橋台の形状に関し、図３や図１１の橋台２１，４１のように楔状としてもよいし、図１２の橋台５１のように一定厚さの部材を傾斜させてもよい。   Further, regarding the shape of each abutment, a wedge shape may be used like the abutments 21 and 41 in FIGS. 3 and 11, or a member having a certain thickness may be inclined like the abutment 51 in FIG.

また、図１２（ａ）に示すように、階段状端部を有する補強盛土３０と平坦傾斜面を有する橋台５１とを組み合わせる場合、図１２（ｂ）に示すように、三角柱状のスペーサＳＰを、補強盛土３０と橋台５１との隙間に設けてもよい。これにより、施工の容易化が図れる。   Moreover, as shown in FIG. 12A, when the reinforcing embankment 30 having stepped ends and the abutment 51 having a flat inclined surface are combined, as shown in FIG. Alternatively, it may be provided in the gap between the reinforcing embankment 30 and the abutment 51. Thereby, the construction can be facilitated.

また、各外側表面の傾斜角度θ２は、各橋台が構築される地盤Ｇの状態や荷重等の設計条件に応じて個別に定められる。すなわち、その地盤Ｇにおける荷重の分散角度θ１、地盤Ｇが持つ地耐力、橋梁の上載荷重、橋梁の自重、設計震度等を考慮して定めることになる。   In addition, the inclination angle θ2 of each outer surface is individually determined according to the design conditions such as the state of the ground G on which each abutment is built and the load. That is, it is determined in consideration of the load dispersion angle θ1 on the ground G, the earth bearing strength of the ground G, the load on the bridge, the weight of the bridge, the design seismic intensity, and the like.

また、前述の実施形態では、左側橋台と右側橋台のそれぞれについて、外側表面を傾斜面で構成した。ここで、片側の橋台が構築される地盤Ｇに十分な支持力があれば、反対側の橋台についてのみ、外側表面を傾斜面にしてもよい。   Moreover, in the above-mentioned embodiment, the outer surface was comprised by the inclined surface about each of the left side abutment and the right side abutment. Here, as long as the ground G on which one abutment is constructed has sufficient supporting force, the outer surface may be inclined only for the opposite abutment.

さらに、各実施形態の技術を組み合わせることも可能である。例えば、図３の階段状傾斜面に代えて図１１のフラットな傾斜面としてもよい。同様に、図１２の傾斜状橋台５１に代えて図１１の楔状橋台４１を用いてもよい。   Furthermore, it is possible to combine the techniques of the embodiments. For example, the flat inclined surface of FIG. 11 may be used instead of the stepped inclined surface of FIG. Similarly, a wedge-shaped abutment 41 of FIG. 11 may be used instead of the inclined abutment 51 of FIG.

１０…ポータルラーメン橋，１１…左側橋台，１１ａ…左側橋台の外側表面，１２…右側橋台，１２ａ…右側橋台の外側表面，１３…主桁，２０…ポータルラーメン橋，２１…左側橋台，２１ａ…左側橋台の外側表面（２１ｂ…垂直面，２１ｃ…水平面），２２…右側橋台，２２ａ…右側橋台の外側表面（２２ｂ…垂直面，２２ｃ…水平面），２３…主桁，３０…補強盛土，３１（３１Ａ〜３１Ｊ）…補強シート，３２（３２Ａ〜３２Ｊ）…締固め層，４０…ポータルラーメン橋，４１…橋台，４２…主桁，５１…橋台，１００…単純桁橋，１０１…支承，１０２…橋台，１０３…主桁，１０４…フーチング，１１０…ラーメン橋，１１１…橋台，１１２…主桁，１１３…基礎杭，Ｇ…地盤，Ｇａ…法面，Ｚ…土，ＳＰ…スペーサ DESCRIPTION OF SYMBOLS 10 ... Portal ramen bridge, 11 ... Left abutment, 11a ... Outer surface of left abutment, 12 ... Right abutment, 12a ... Outer surface of right abutment, 13 ... Main girder, 20 ... Portal ramen bridge, 21 ... Left abutment, 21a ... Outer surface of left abutment (21b ... vertical surface, 21c ... horizontal plane), 22 ... right abutment, 22a ... outer surface of right abutment (22b ... vertical surface, 22c ... horizontal plane), 23 ... main girder, 30 ... reinforcing embankment, 31 (31A-31J) ... Reinforcement sheet, 32 (32A-32J) ... Consolidation layer, 40 ... Portal ramen bridge, 41 ... Abutment, 42 ... Main girder, 51 ... Abutment, 100 ... Simple girder bridge, 101 ... Support, 102 ... Abutment, 103 ... Main girder, 104 ... Footing, 110 ... Ramen bridge, 111 ... Abutment, 112 ... Main girder, 113 ... Foundation pile, G ... Ground, Ga ... Slope, Z ... Soil, SP ... Spacer

Claims (4)

一対の橋台と主桁とを備え、前記一対の橋台と前記主桁とを剛結合したポータルラーメン橋であって、
一方の橋台は、他方の橋台とは反対側に位置する外側表面が、上方に向かう程に前記他方の橋台から離れる方向へ傾いていることを特徴とするポータルラーメン橋。 A portal ramen bridge comprising a pair of abutments and a main girder, wherein the pair of abutments and the main girder are rigidly connected,
One of the abutments is a portal ramen bridge characterized in that an outer surface located on the opposite side of the other abutment is inclined in a direction away from the other abutment as it goes upward. 前記橋台の外側表面に沿って補強盛土を設けることを特徴とする請求項１に記載のポータルラーメン橋。   The portal ramen bridge according to claim 1, wherein a reinforcing embankment is provided along an outer surface of the abutment. 前記補強盛土は、前記橋台の外側表面に近い側の端部が階段状となるように積層することで設けられ、
前記橋台の前記外側表面は平坦な傾斜面とされ、
前記平坦な傾斜面と前記補強盛土の階段状の端部との間の隙間に三角柱状のスペーサを設けたことを特徴とする請求項２に記載のポータルラーメン橋。 The reinforcing embankment is provided by laminating so that the end on the side close to the outer surface of the abutment is stepped,
The outer surface of the abutment is a flat inclined surface,
The portal ramen bridge according to claim 2, wherein a triangular columnar spacer is provided in a gap between the flat inclined surface and the stepped end of the reinforcing embankment . 前記橋台の外側表面における傾斜角度は、前記橋台に作用する鉛直荷重を受ける地盤の面積と、前記地盤における鉛直荷重の分散角度に基づいて定められていることを特徴とする請求項１から３の何れか１項に記載のポータルラーメン橋。 The inclination angle in the outer surface of the abutment is 3 and the area of ground which receives the vertical load acting on the bridge abutment, claim 1, characterized in that are determined based on the angular spread of the vertical load before Symbol Ground Portal ramen bridge according to any one of the above.
JP2011106354A 2011-05-11 2011-05-11 Portal ramen bridge with improved vertical load dispersion Expired - Fee Related JP6055588B2 (en)

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