JP6448089B2 - How to build an arch bridge - Google Patents

Description

  The present invention relates to a method for constructing a continuous arch bridge.

  Conventionally, in a single arch bridge, a lowering method has been known as a method of laying the arch rib (see “Patent Document 1”).

  In this lowering method, the arch rib is constructed by constructing the arch rib in a substantially vertical direction from the rotation support installed on the arch abutment, and then rotating the arch rib to the construction span side (ie, lowering). It has become.

  On the other hand, conventionally, as a structure of an arch bridge, for example, a continuous arch bridge in which arch ribs are respectively disposed between erection diameters on both sides of a pier like a balanced arch bridge is known.

  The arch ribs in such a continuous arch bridge are conventionally constructed by a construction method using a mobile support (see “Patent Document 2”), an overhang construction method using a mobile work vehicle, or the like.

JP 2003-321805 A Japanese Unexamined Patent Publication No. Hei 8-209963

  Even with continuous arch bridges, if the lowering method is used when arch ribs are installed, it is possible to improve the construction quality compared to the conventional overhanging method, etc. Arise.

  That is, in the lowering method, in order to smoothly perform the operation of rotating the arch rib constructed in a substantially vertical direction to the span between the installation spans, a cable is fastened to the vicinity of the tip end of the arch rib and tension is applied to the cable. However, it is necessary to install a reaction force support structure for resisting this tension.

  As the reaction force support structure, a structure in which an anchor block is fixed to the ground behind the arch abutment with a ground anchor and a cable is fastened to the anchor block has been conventionally employed.

  However, since such a reaction force support structure becomes a large-scale temporary structure, the construction cost of the arch ribs is high and the construction period is long. In addition, when the lowering method is applied to arch ribs in a continuous arch bridge, it is often difficult to select a suitable location for installing the reaction force support structure.

  The present invention has been made in view of such circumstances, and is intended to reduce the erection cost and the erection period after enabling the lowering method to be applied to the arch rib erection in the continuous arch bridge. It aims at providing the construction method of the arch bridge which can do.

  The present invention is intended to achieve the above object by effectively utilizing the arch rib located on the opposite side of the pier to the arch rib to which the lowering method is applied.

That is, the arch bridge erection method according to the present invention is:
In the method of constructing an arch bridge in which first and second arch ribs are respectively arranged between first and second diameters located on both sides of a pier,
Building the base end of the pier,
Installing a first and a second rotary bearing that is rotatable about an axis extending in a direction perpendicular to the bridge axis at the base end of the pier;
Constructing the first arch rib in a substantially vertical direction from the first rotation bearing;
Constructing the second arch rib in a substantially horizontal direction from the second rotation support toward the second span;
In a state where the first and second arch ribs are connected to each other by a cable, the first arch rib is turned to the first span side to the erected position by sending out the cable, and then the position after the turning. Fixing the first arch rib with:
And a step of rotating the second arch rib upward to a planned installation position and then fixing the second arch rib at the position after the rotation.

  The above-mentioned “base end portion of the pier” may be a lower end portion of the pier main body, or may be a portion of the pier foundation that supports the pier main body.

  The construction of the “first and second arch ribs” may be performed at the same time, or one of them may be preceded.

  A specific method for fixing the “first arch rib” at the position after the rotation is not particularly limited.

  The specific method for rotating the “second arch rib” above is not particularly limited, and the specific method for fixing the second arch rib at the position after the rotation is also particularly limited. It is not something.

  In the present invention, the first and second arch ribs are constructed in the substantially vertical direction and the substantially horizontal direction from the first and second rotating bearings installed at the base end portion of the pier, respectively. Such effects can be obtained.

  That is, if the first and second arch ribs are erected by the overhanging method as in the prior art, the arch ribs will be added one block at a time in the diagonally upward direction, so it is erected while ensuring construction quality. It is not easy, and it takes time for the construction work. On the other hand, by constructing the first and second arch ribs in the substantially vertical direction and the substantially horizontal direction as in the present invention, the construction period can be shortened while ensuring the construction quality.

  In particular, when the first and second arch ribs are made of concrete, the concrete filling property can be improved by constructing them in a substantially vertical direction and a substantially horizontal direction, respectively. And can improve the construction quality.

  In addition, according to the present invention, the first arch rib constructed in the substantially vertical direction from the first rotation support and the second arch rib constructed in the substantially horizontal direction from the second rotation support to the second span are connected to the cable. Since the first arch rib is rotated to the first span side to the erected position by sending out the cable in the connected state, the following operational effects can be obtained.

  That is, when the first arch rib is rotated to the first span side, the second arch rib can be used as a reaction force support structure against the tension of the cable. Therefore, it is not necessary to install a conventional temporary structure as the reaction force support structure, thereby reducing the construction cost of the first arch rib and shortening the construction period. In addition, the installation location of the reaction force support structure can be easily selected.

  If the second arch rib alone is not sufficient in terms of weight as the reaction force support structure against the cable tension, it is necessary to additionally install a temporary structure such as a counterweight or a ground anchor. Since the structure is installed in an auxiliary manner, the structure can be simplified.

  As described above, according to the present invention, it is possible to reduce the erection cost and shorten the erection period while making the lowering method applicable to the arch rib erection in the continuous arch bridge.

  Moreover, in this invention, since the 1st and 2nd rotation bearing is installed in the base end part of the same pier, it becomes possible to give the 1st and 2nd rotation bearing the continuity on intensity | strength easily. . And by doing in this way, the horizontal reaction force from the 1st arch rib and the horizontal reaction force from the 2nd arch rib cancel each other in the 1st and 2nd rotation bearings, and the 1st and 2nd rotation bearings should bear Horizontal reaction force can be minimized.

  At this time, if a pin bearing having a common rotating shaft is used as the first and second rotating bearings, the horizontal reaction force from the first arch rib and the horizontal reaction force from the second arch rib are obtained on this rotating shaft. It is possible to cancel, thereby minimizing the horizontal reaction force that must be borne by the first and second rotary bearings.

  In the present invention, the rotation of the first arch rib toward the first span is performed. After the anchor block is installed on the second arch rib and the jack is attached to the anchor block, one end of the cable is fastened to the first arch rib. If the cable is sent out by a jack in a state, the cable can be easily sent out.

  In the present invention, after the first arch rib rotated to the first span side is fixed at the planned installation position, the second arch rib is rotated upward. If this is performed by drawing in the cable connected to the first and second arch ribs, the following effects can be obtained.

  That is, the first arch rib fixed at the planned erection position can be used as a reaction force support structure against the tension of the cable when the second arch rib is rotated, thereby reducing the erection cost and erection efficiency of the second arch rib. Improvements can be made.

  At that time, if the cable used when the first arch rib is rotated to the first span side is used as it is, it is possible to further promote the construction cost reduction and the construction efficiency improvement of the second arch rib.

  In addition, when the first arch rib is rotated to the first span side, the anchor block and the jack installed on the second arch rib are used when the cable is drawn when the second arch rib is rotated upward. Is also possible. In such a case, it is possible to perform the erection work more efficiently without changing the jack.

  In the present invention, if the first arch rib is fixed after turning by closing the first arch rib with the other arch ribs between the first diameters, the first arch ribs are installed between the first diameters by this closing. The entire arch rib can be utilized as a reaction force support structure against the tension of the cable when the second arch rib is rotated upward.

  In the present invention, the abutment or the second pier is constructed at a position away from the pier to the second span side, the second arch rib is fixed after rotation, and the tip of the second arch rib is extended. If the second arch rib is connected to the abutment or the second pier, the arch rib can be efficiently installed over the entire second span without using a mobile work vehicle or the like.

The side view which shows the arch bridge used as the object of the construction method which concerns on one Embodiment of this invention Side view showing the arch bridge erection process by the erection method (Part 1) Side view showing the erection process (Part 2) Side view showing the erection process (Part 3) Detailed view of V section in FIG. Detailed view of VI section in Fig. 5 VII direction arrow view of FIG. The same figure as FIG. 4 which shows the modification of the said embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a side view showing an arch bridge 10 that is an object of a construction method according to an embodiment of the present invention.

  As shown in the figure, the arch bridge 10 is a balanced arch bridge 10 in which a central span arch 20 and side span arches 30 on both sides thereof are continuously formed, and is an upper concrete arch bridge. It is configured as.

  The center span arch 20 is connected to the base ends of a pair of bridge piers 40 that are installed at both ends of the center span. On the other hand, each side span arch 30 has an arch shape that is substantially half of the central span arch 20, and its base end is connected to the base end of each pier 40, and its tip 30 a It connects with the upper end part of the abutment 50 installed in the edge part on the opposite side between each side diameter.

  Each pier 40 includes a pier foundation 42 embedded in the ground 2 and a pier body 44 extending upward from the pier foundation 42, and a central span arch 20 and each side span are provided at a lower end 44 a of the pier body 44. The arch 30 is connected.

  A plurality of vertical members 52 are arranged on the upper surfaces of the central span arch 20 and the side span arches 30. Further, stiffening girders 54 constituting a floor slab are arranged at the upper end portions of the central span arch 20 and the side span arches 30 and the top ends of the bridge piers 40 and the vertical members 52. Note that the distal end portion 30 a of each side-diameter arch 30 is formed so that the upper surface thereof is flush with the upper surface of the stiffening girder 54.

  Next, the construction method of the arch bridge 10 according to the present embodiment will be described.

  FIGS. 2-4 is a side view which shows the construction process of the arch bridge 10 by the construction method concerning this embodiment. FIG. 5 is a detailed view of a portion V in FIG.

  First, as shown in FIG. 2 (a), the pier foundation 42 of each pier 40 is embedded in the ground 2 located at both ends of the center span, and the lower end portion of the pier body 44 of each pier 40 is placed on the upper end surface thereof. 44a is constructed. And the 1st rotation bearing 22 for the center span arch 20 and the 2nd rotation bearing 32 for the side span arch 30 are installed in the upper surface of the lower end part 44a of each pier main body 44. As shown in FIG. These detailed structures will be described later.

  Moreover, the abutment 50 is each constructed | assembled in the ground 2 located in the edge part on the opposite side between each side diameter.

  Next, as shown in FIG. 2B, the second arch rib 30A constituting the main portion of each side-diameter arch 30 (that is, the portion excluding the tip portion 30a of the side-diameter arch 30) is changed to each side diameter. It is constructed so as to extend in a substantially horizontal direction. This construction is performed by installing a support work 102 on the ground 2 between each side diameter.

  After constructing each second arch rib 30A in this way, the anchor block 104 is installed on the upper surface in the vicinity of the tip.

  Next, as shown in FIG. 2C, the first arch rib 20 </ b> A constituting approximately half of the central span arch 20 is constructed in the vertical direction from the lower end 44 a of each pier body 44. This construction is performed by installing a support work (not shown) on the ground 2 around each pier foundation 42.

  When constructing each of the first arch ribs 20A, the stay member 106 is installed between the vicinity of the base end of the first arch rib 20A and the vicinity of the base end of the second arch rib 30A, and both are connected to each other. The arch rib 20A is prevented from inadvertently falling down to the center span side.

  Next, as shown in FIGS. 3A and 5, the first arch ribs 20 </ b> A and the second arch ribs 30 </ b> A are connected by the PC cable 108. At that time, the jack 110 is attached to the anchor block 104 installed in the vicinity of the tip of each second arch rib 30A, and one end of each PC cable 108 is inserted into each anchor block 104 and connected to each jack 110. To do. On the other hand, the other end of each PC cable 108 is fastened to the vicinity of the tip of each first arch rib 20A.

  Thereafter, the connection between each stay member 106 and each first arch rib 20A is released, and each jack cable 110 sends out each PC cable 108, thereby rotating each first arch rib 20A toward the center span side.

  As a result, as shown in FIG. 3B, when each first arch rib 20 </ b> A rotates to the planned construction position of the central span arch 20, the feeding of each PC cable 108 is stopped. At this time, the pair of first arch ribs 20A are arranged in a state of facing each other leaving a slight gap (for example, a gap of 1 m or less) between the front end surfaces.

  Next, as shown in FIG. 3 (c), the suspension scaffold 112 is installed so as to straddle the front ends of the pair of first arch ribs 20A, and concrete is placed in a slight gap between the two. Are connected. Thereby, the center span arch 20 in which the arch crown portion 20a is closed is completed.

  Next, as shown in FIG. 4A, after the anchor block 104 and the jack 110 installed in the vicinity of the tip of each second arch rib 30A are removed, one end of each PC cable 108 is connected to each second cable. The state where the arch rib 30A is fastened to the vicinity of the tip, the anchor block 114 is installed on the upper surface of the arch crown portion 20a of the central span arch 20, and the other end of each PC cable 108 is inserted into the anchor block 114 Then, each of the jacks 120 attached to the anchor block 114 is connected.

  Thereafter, each PC cable 108 is pulled in by each jack 120, thereby rotating each second arch rib 30 </ b> A upward to a planned construction position of each side-diameter arch 30.

  Next, as shown in FIG. 4 (b), an overhanging scaffold 116 is installed from the upper end of each abutment 50 toward each side diameter, and each side-diameter arch 30 extends from the tip surface of each second arch rib 30 </ b> A. The tip 30a is extended. Thereby, each 2nd arch rib 30A is connected to each abutment 50, and each side span arch 30 is completed.

  Next, as shown in FIG. 4 (c), after removing each overhanging scaffold 116, each PC cable 108, anchor block 114 and each jack 120, the remaining part of each pier body 44 (that is, the part other than the lower end part 44a). And a plurality of vertical members 52 are arranged on the upper surfaces of the central span arch 20 and each side span arch 30.

  Finally, as shown in FIG. 1, the stiffening girders 54 disposed on the upper end portions of the central span arch 20 and the side span arches 30 and the top ends of the bridge piers 40 and the vertical members 52 are performed.

  FIG. 6 is a detailed view of the VI part of FIG. FIG. 7 is a view taken in the direction of arrow VII in FIG.

  As shown in FIG. 7, the first rotation bearings 22 for the central span arch 20 are installed at two positions at a necessary interval in the direction orthogonal to the bridge axis, and the second rotation for each side span arch 30. The bearings 32 are installed at two locations at a required interval in the direction orthogonal to the bridge axis inside the pair of first rotating bearings 22.

  Each of the first rotation supports 22 is a rotation in which an upper shoe 22A fixed to the base end surface of the first arch rib 20A and a lower shoe 22B fixed to the upper surface of the lower end portion 44a of the pier body 44 extend in a direction orthogonal to the bridge axis. The shaft 60 is rotatably connected.

  Each second rotation support 32 includes an upper shoe 32A fixed to the base end surface of the second arch rib 30A and a lower shoe 32B fixed to the upper surface of the lower end portion 44a of the pier body 44 via the rotation shaft 60. And are pivotally connected.

  That is, each of the pair of first rotation bearings 22 and the pair of second rotation bearings 32 is configured as a pin bearing having a common rotation shaft 60.

  As shown in FIG. 6, the base end portions 20Ab and 30Ab of the first and second arch ribs 20A and 30A are formed so as to narrow in a wedge shape toward the upper shoes 22A and 32A in a side view. Thus, when the first and second arch ribs 20A and 30A are constructed, they do not interfere with each other.

  Next, the effect of this embodiment is demonstrated.

  In the present embodiment, the first and second arch ribs 20A, 30A are substantially vertical from the first and second rotary supports 22, 32 installed at the lower end 44a of the pier body 44 (ie, the base end of the pier 40). Since it is constructed in the direction and the substantially horizontal direction, the following operational effects can be obtained.

  In other words, if the first and second arch ribs 20A, 30A are installed by the overhang method as in the prior art, the arch ribs are added one block at a time in the diagonally upward direction, so that the construction quality is ensured. It is not easy to do so, and the construction work takes time. On the other hand, by constructing the first and second arch ribs 20A, 30A in the substantially vertical direction and the substantially horizontal direction as in the present embodiment, the construction period can be shortened while ensuring the construction quality. .

  In particular, the arch bridge 10 that is a target of the erection method according to the present embodiment is a concrete arch bridge, and the first and second arch ribs 20A and 30A are also made of concrete. As a result, it is possible to improve the filling property of the concrete, thereby improving the construction quality as compared with the case of the overhanging method.

  In addition, in the present embodiment, the first arch rib 20A constructed in the substantially vertical direction from the first rotation support 22 and the second rotation support 32 in the substantially horizontal direction toward the side span (second span). In a state where the constructed second arch rib 30A is connected with the PC cable 108, the first arch rib 20A is rotated to the center span (first span) side to the planned installation position by feeding out the PC cable 108. Therefore, the following effects can be obtained.

  That is, when the first arch rib 20A is rotated to the center span side, the second arch rib 30A can be used as a reaction force support structure against the tension of the PC cable 108. Therefore, it is not necessary to install a conventional temporary structure as the reaction force support structure, thereby reducing the construction cost of the first arch rib 20A and shortening the construction period. In addition, the installation location of the reaction force support structure can be easily selected.

  Thus, according to the present embodiment, it is possible to apply the lowering method to the construction of the first arch rib 20 in the continuous arch bridge 10 and to reduce the construction cost and the construction period.

  When the construction method according to the present embodiment is employed, when a situation occurs in which the second arch rib 30A alone is not sufficient in terms of weight as a reaction force support structure against the tension of the PC cable 108, the counterweight It is necessary to additionally install a temporary structure such as a ground anchor or the like. In this case, the temporary structure is installed in an auxiliary manner, so that a simple structure can be obtained.

  In the present embodiment, the first arch rib 20A is turned to the center span side. After the anchor block 104 is installed on the second arch rib 30A and the jack 110 is attached to the anchor block 104, the first arch rib 20A is moved. Since the PC cable 108 is sent out by the jack 110 while one end of the PC cable 108 is fastened, the PC cable 108 can be easily sent out.

  Further, in the present embodiment, after the first arch rib 20A rotated to the center span side is fixed at the planned installation position, when the second arch rib 30A is rotated upward, the first and second rotations are performed. Since the operation is performed by drawing the PC cable 108 connected to the arch ribs 20A and 30A, the following operational effects can be obtained.

  That is, the first arch rib 20 </ b> A fixed at the planned installation position can be used as a reaction force support structure against the tension of the PC cable 108.

  Further, since the PC cable 108 used for the rotation of the first arch rib 20A is used as it is, it is possible to reduce the construction cost and improve the construction efficiency of the second arch rib 30A. When the second arch rib 30A is rotated upward, a PC cable different from the PC cable 108 used to rotate the first arch rib 20A can be used.

  In the present embodiment, since the pin bearings having the common rotation shaft 60 are used as the first and second rotation bearings 22 and 32, the horizontal reaction force from the first arch rib 20A and the second reaction force on the rotation shaft 60 are used. The horizontal reaction force from the arch rib 30A can be canceled out, and thereby the horizontal reaction force to be borne by the first and second rotary bearings 22 and 32 can be minimized.

  At this time, the pair of first rotary bearings 22 for the central span arch 20 are disposed outside the pair of second rotary bearings 32 for the side span arch 30, and therefore the central span arch 20. Rotation of the first arch rib 20A that constitutes can be performed with high accuracy.

  Furthermore, in the present embodiment, the first arch rib 20A is fixed after being rotated by closing the first arch rib 20A with the first arch rib 20A (other arch ribs) facing the first arch rib 20A on the center span side. Therefore, when the second arch rib 30A is rotated upward, the central span arch 20 installed between the central spans by this closing is utilized as a reaction force support structure against the tension of the PC cable 108. Can do.

  In the present embodiment, the abutment 50 is constructed at a position away from each pier 40 to the side span side, and the second arch rib 30A is fixed after the rotation from the front end surface of the second arch rib 30A. Since the tip 30a of the two arch ribs 30A is extended and connected to the abutment 50, the side span arch 30 is efficiently installed over the entire side span without using a mobile work vehicle or the like. be able to.

  In the embodiment described above, the first arch rib 20A is constructed after the second arch rib 30A is constructed. However, the first arch rib 20A may be constructed in parallel with the construction of the second arch rib 30A. Is possible.

  In the said embodiment, although demonstrated as what constructs the abutment 50 in the position away from each bridge pier 40 to the side span side, it is also possible to construct a 2nd abutment instead of the abutment 50.

  In the above embodiment, the PC cable 108 is used to rotate the first and second arch ribs 20A and 30A. However, a steel wire or the like can be used instead of the PC cable 108.

  In the said embodiment, although the arch bridge 10 used as construction object was demonstrated as what was a balanced arch bridge, if it is a continuous type arch bridge, even if it is an arch bridge other than this, the construction method which concerns on this invention Can be adopted.

  In the above embodiment, the arch bridge 10 to be installed is described as an upper arch bridge. However, the erection method according to the present invention can be employed even when the arch bridge 10 is a middle arch bridge. .

  In the above embodiment, the arch bridge 10 to be installed is described as a concrete arch bridge. However, even when a part or all of the arch bridge is made of steel, the installation method according to the present invention is adopted. Is possible.

  Next, a modification of the above embodiment will be described.

  FIG. 8 is a process diagram similar to FIG. 4 showing the erection method according to this modification.

  As shown in the figure, the erection method according to this modification is the same in the basic process as in the above embodiment, but the process of laying the second arch rib 30A is different from that in the above embodiment. Yes.

  That is, in this modified example, as shown in FIG. 8A, after the central span arch 20 is completed, the anchor block 104 and the jack 110 installed in the vicinity of the tip of each second arch rib 30A can be removed. The second arch ribs 30 </ b> A are rotated upward to the erection position of each side span arch 30 by pulling each PC cable 108 with each jack 110.

  In this modification as well, as shown in FIG. 8B, the overhanging scaffold 116 is extended from the upper end of each abutment 50 toward the side span, and the distal end portion 30Aa of each second arch rib 30A is extended. Then, after connecting each second arch rib 30A to each abutment 50, each overhanging scaffold 116, each PC cable 108, anchor block 104 and jack 110 are removed.

  As in this modification, when the first arch ribs 20A are rotated upward, the anchor block 104 and the jack 110 installed in the vicinity of the tip of each second arch rib 30A are used as they are, so that the erection efficiency is improved. This can be further improved.

  In addition, the numerical value shown as a specification in the said embodiment and its modification is only an example, and of course, you may set these to a different value suitably.

  The invention of the present application is not limited to the configuration described in the above-described embodiment and its modifications, and a configuration with various other changes can be adopted.

2 ground 10 arch bridge 20 central span arch 20a arch crown 20A first arch rib 20Ab, 30Ab base end 22 first rotary bearing 22A, 32A upper shoe 22B, 32B lower shoe 30 side span arch 30a tip 30A second Arch rib 32 Second rotation support 40 Bridge pier 42 Bridge pier foundation 44 Bridge pier main body 44a Lower end 50 Abutment 52 Vertical material 54 Stiffening girder 60 Rotating shaft 102 Support work 104, 114 Anchor block 106 Stay material 108 PC cable (cable)
110, 120 Jack 112 Suspended scaffold 116 Overhang scaffold

Claims (6)

In the method of constructing an arch bridge in which first and second arch ribs are respectively arranged between first and second diameters located on both sides of a pier,
Building the base end of the pier,
Installing a first and a second rotary bearing that is rotatable about an axis extending in a direction perpendicular to the bridge axis at the base end of the pier;
Constructing the first arch rib in a substantially vertical direction from the first rotation bearing;
Constructing the second arch rib in a substantially horizontal direction from the second rotation support toward the second span;
In a state where the first and second arch ribs are connected to each other by a cable, the first arch rib is turned to the first span side to the erected position by sending out the cable, and then the position after the turning. Fixing the first arch rib with:
An arch bridge erection method comprising: rotating the second arch rib upward to a erection planned position, and then fixing the second arch rib at the position after the rotation. Rotation of the first arch rib toward the first span side,
After the anchor block is installed on the second arch rib and a jack is mounted on the anchor block, the cable is sent out by the jack in a state where one end of the cable is fastened to the first arch rib. An arch bridge erection method according to claim 1.   The arch bridge erection method according to claim 1 or 2, characterized in that the second arch rib is rotated upward by drawing in a cable connected to the first and second arch ribs.   The arch bridge erection method according to any one of claims 1 to 3, wherein a pin bearing having a common rotating shaft is used as the first and second rotating bearings.   The fixing at the position after the rotation of the first arch rib is performed by closing the first arch rib with another arch rib between the first diameters. How to build an arch bridge. Build the abutment or the second pier at a position away from the pier to the second span side,
The second arch rib is fixed at the position after the rotation by extending the tip of the second arch rib and connecting the second arch rib to the abutment or the second pier. An arch bridge erection method according to any one of claims 1 to 5.

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