JP2012255301A - Construction method for upper road type suspended slab bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a change in the side-view arrayed shape of a precast concrete slab arrayed along cables during constructing an upper road type suspended slab bridge where columns are erected on a thin concrete plate-like member (suspended slab) supported by the cables and an upper road girder is supported thereon.SOLUTION: A precast concrete slab 21 is arrayed between end blocks 3 and 4, and then water reserving containers 30 are placed on the precast concrete slab. Along with columns 8 erected thereon and segments 23 arranged to form an upper road girder 9, the amount of water in the containers placed on the precast concrete slab is adjusted to approximately uniform the distribution of a load carried in the axial direction of cables 12a. To adjust the amount of water, various methods are applied. For example, water equivalent to the working load is discharged from the containers near a position where a new load works, to remove the load, or the discharged water can be distributed into the other containers.

Description

  In the present invention, an upright suspension floor slab bridge, which is a type of bridge, that is, a pillar is erected on a thin concrete plate-like member (suspended floor slab) supported along a stretched cable, and a road surface is placed thereon. The present invention relates to a method for constructing an upper suspension-type slab bridge that supports upper girders for forming.

The upper-floor suspended floor slab bridge is a thin concrete plate-like member with a high tension cable stretched between the piers, between the abutments or between the piers and the abutments, and with a deflection (sag) along the cable. Support the suspended floor slab). And a support | pillar is set up on the suspended floor slab which is a plate-shaped member, and an upper road girder is built on this.
In a suspended floor slab bridge where the upper surface of the suspended floor slab is the road surface, a slope is generated on the road surface due to the sag of the suspended floor slab. be able to. Moreover, it can also be set as what is called a self-supporting type suspension floor slab bridge which connects the both ends of a suspension floor slab with an upper road girder, transmits the tensile force which acts on a suspension floor slab to an upper road girder, and acts as a compression force on an upper road girder. As a result, the horizontal reaction force acting on the abutment or pier is reduced, and the stability of the abutment and the like in the completed system can be improved.

As a method for constructing such an upper suspension type slab bridge, there is one disclosed in Patent Document 1, for example.
In this construction method, a structural unit composed of a precast concrete board for forming a suspended floor slab and two struts standing obliquely thereon is supported by a cable stretched between two abutments. . And it moves along this cable and arranges sequentially from the position adjacent to the abutment. Subsequently, a precast concrete segment serving as an upper girder is supported on the column of the structural unit, and is sequentially arranged at a predetermined interval in the axial direction of the bridge from a position adjacent to one abutment. Thereafter, concrete is placed between the precast concrete plates arranged along the cable and between the segments of the precast concrete arranged above, and the precast concrete plates and the segments are suspended floor plates that are continuous in the axial direction of the bridge, and This is the upper girder. In addition, the precast concrete board used as a suspended floor slab may be made into the continuous suspended floor slab by placing concrete between each board before constructing an upper girder.

JP 2001-182016 A

However, the following problems may occur in the construction of the above-described upper suspension type slab bridge.
The upper suspension type slab bridge is a structure that supports the suspended slab on the cable where the deflection occurs, so if the load is concentrated during construction or if the load acts in a range that is biased in the axial direction of the bridge, Large deflection occurs near the position where the load acts. And the arrangement | positioning shape of the precast concrete board supported by the cable changes a lot, and the relative angle change and displacement between adjacent boards also become large.

In particular, as shown in FIG. 16, when the precast concrete segments 101 constituting the upper girder are sequentially arranged from a position close to one abutment 111 toward the abutment 112 on the opposite side, an imaginary line in FIG. As shown, the cable 102 largely bends downward at the position where the segment 101a is arranged in the initial stage. As a result, a large relative angular change and relative displacement occur between the adjacent segments 101, and it becomes difficult to connect them. In addition, the precast concrete plate 103 constituting the suspended floor slab also has a large relative displacement between the adjacent plates while being supported by the cable 102, and the precast concrete plate 103 is interfered with by reinforcing bars or the like for connecting them. It can be damaged.
On the other hand, when the suspended floor slab is formed to be continuous before the upper girder is installed, a large bending moment acts on the concrete of the suspended floor slab, and the concrete of the suspended floor slab is cracked.
As described above, when the upper-floor type suspension floor slab bridge is installed, an excessive deformation peculiar to the suspension structure and a bending moment associated therewith are generated due to a change in the load applied.

  The present invention has been made in view of the circumstances as described above, and its purpose is that the precast concrete plate supported by the cable bends greatly due to load fluctuations, that is, viewed from the side of the plate member of the precast concrete. It is intended to provide a method for constructing an upper-floor type suspension floor slab bridge that can be constructed while maintaining a stable state while suppressing a large change in the arrangement shape.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a suspension floor slab which is a thin concrete plate-like member formed along a cable stretched between two opposing abutments or piers. A method for constructing an upper-floor type suspension floor slab bridge having a column erected on a suspension floor slab and an upper girder supported on the column, the step of stretching a cable between an abutment or a pier, and the suspension floor Arranging a plurality of precast concrete plates constituting a plate along the cable and supporting the plates; and on the support columns erected from all the precast concrete plates or a plurality of selected precast concrete plates. A step of constructing an upper girder, and a step of forming concrete between the precast concrete plates to form the continuous suspended floor slab, The step of constructing the upper girder includes injecting water into all the precast concrete plates or a container supported by a plurality of selected precast concrete plates, with respect to an increase in load accompanying the construction of the upper girder, Suppressing the change in the array shape seen from the side of the plurality of precast concrete plates supported along the cable, with the step of discharging the water stored in the container or moving the water between the containers The construction method of the upper-floor type suspension floor slab bridge characterized by performing while doing is provided.

In the construction method of the above-mentioned upper-floor suspended floor bridge, the cable stretched between the abutment or the pier is either between the abutment and the abutment, between the abutment and the pier, or between the abutment and the pier. It may be. These cables may be fixed at both ends of the abutment or pier even when the upper-floor suspension floor slab bridge is completed, or after the suspension floor slab and the upper road girder are formed, The fixing position may be changed to the end portion of the upper girder on the abutment or the pier.
In addition, the support column erected from the precast concrete plate may be erected after the precast concrete plate is supported by the cable and arranged at a predetermined position, or is attached in advance to the precast concrete plate, The precast concrete plate may be supported by a cable together with the support and arranged at a predetermined position.
On the other hand, the step of placing concrete between precast concrete plates to form a suspended floor slab in which a plurality of precast concrete plates are continuous may be performed before the step of building the upper girder, or the step of building the upper girder You may go at the same time. Alternatively, it may be performed when a part of the process of constructing the upper girder is completed or when the construction of the upper girder is completed.

  In this method of constructing an upper-floor type suspension floor slab bridge, by adjusting the amount of water in the container supported by the precast concrete plate, a load acts on a limited range in the axial direction of the cable along with the construction of the upper channel girder. When a concentrated load is applied, it is possible to cancel the newly applied load, or to distribute the load variation over a wide range. That is, when a load is newly loaded in the limited range, the increase in the load is offset by discharging the stored water from the container disposed in the loading range or a range close thereto. In addition, by supplying water to each of the containers arranged in a wide range, it is possible to mitigate changes in the cable shape due to the load being concentrated on a limited narrow range. This reduces relative angular changes and displacements between the precast concrete plates arranged along the cable. Further, when concrete is cast between precast concrete plates arranged along the cable and these are continuous suspended floor slabs, bending stress generated in the suspended floor slab is reduced.

  The invention according to claim 2 is the construction method of the upper suspension type slab bridge according to claim 1, wherein the step of injecting water, discharging water or moving water between the containers is performed by the upper girder. Corresponding to the loading of the load accompanying the construction, the water in the container provided near the loading position of the load is moved to another container or discharged.

  In this construction method of the upper-floor suspension floor slab bridge, the total amount and distribution of the load supported by the cable is increased by discharging the amount of water corresponding to the load increased with the construction of the upper girder. Large fluctuations can be suppressed. Further, by distributing the discharged water to a plurality of other containers, the loaded state is almost the same as when the load is distributed over a wide range in the axial direction of the cable. Therefore, it is suppressed that the arrangement | positioning shape of the precast concrete board arranged along the cable changes greatly, and the relative angle change and displacement between adjacent precast concrete boards become small.

  The invention according to claim 3 is the construction method of the upper suspension type slab bridge according to claim 1, wherein the step of injecting water, discharging water or moving water between the containers is performed by the upper girder. When the load is loaded on one end side from the center point in the axial direction of the cable corresponding to loading of the load accompanying the construction, the water stored in the container on the end side on which the load is loaded Is moved to the container provided on the other end side from the center point, or water is poured into the container provided on the other end side.

  In this method of constructing an upper-floor suspension floor slab bridge, when a new load is applied to one end side of the cable in the axial direction, the load is applied to both sides of the center point. Uneven deflection is suppressed. That is, when a new load is applied to one end side from the center point, it is possible to suppress the occurrence of a large downward deflection in the vicinity of the position where the load is applied. Similarly, when a new load is applied to one end side from the center point, water is poured into a container disposed on the other end side so that the load is applied to both sides of the cable center point. It will act, and it can control that a deflection occurs unevenly.

  According to a fourth aspect of the present invention, in the method for constructing the upper suspension type slab bridge according to any one of the first to third aspects, water remains in the container after the step of constructing the upper girder. The discharge of the total amount of water stored in the container and the removal of the container were performed by placing concrete between the precast concrete plates and fixing both ends of the cable supporting the precast concrete plates. This is performed after the suspended floor slab continuous between structures is formed.

In the construction method of this upper-floor type suspension floor slab bridge, in the case of an upper-floor type suspension floor slab bridge in which the suspension floor slab is continuous with the abutment or the pier, and the cable supporting the suspension floor slab is fixed to the abutment or the pier, the structure is an abutment or After the suspension deck is formed so as to be continuous between the abutment or the pier, the water remaining in the container is discharged and the container is removed. A decrease in load due to discharge of water reduces the sag of the cable, and prestress is introduced in the axial direction of the suspended floor slab.
On the other hand, in the case of a self-supporting suspended floor slab bridge in which both ends of the suspended floor slab are connected to the upper girder, and the tensile force acting on the suspended floor slab is transmitted to the upper girder to introduce the compressive force into the upper girder, the above structure is It becomes a structural member which is continuous with both ends of these upper beams. After both ends of the cable supporting the precast concrete plate are fixed to these structural members and the reaction force is transmitted to the upper girder, the water remaining in the container is discharged and the container is removed. This introduces prestress in the axial direction of the suspended floor slab. Thus, prestress can be easily introduced into the suspended floor slab by discharging the water remaining in the container.

  The invention according to claim 5 is the construction method of the upper-floor type suspended floor slab bridge according to any one of claims 1 to 4, wherein the column is erected in advance on the precast concrete plate, and the precast concrete plate is The cable is supported by the cable, the container in which water is stored is supported by the precast concrete board, and the precast concrete board is moved along the cable and arranged at a predetermined position.

  In this method for constructing an upper suspension type slab bridge, the precast concrete plate is supported by the cable in a state of supporting a container storing water, and the center of gravity can be maintained at a low position even when the support column is erected. For this reason, the precast concrete board can be suspended and supported in a stable state. Thereby, it becomes possible to move and arrange the precast concrete board to which the support column is attached along the cable in a stable state. In addition, efficient work can be performed by attaching the column to the precast concrete board in advance.

  The invention according to claim 6 is the construction method of the upper-floor type suspended floor slab bridge according to any one of claims 1 to 5, wherein both end edges in the width direction of the precast concrete plate arranged along the cable The container is suspended and supported substantially at the center in the width direction of the precast concrete plate by a suspension member joined in the vicinity and stretched obliquely downward toward a substantially central portion in the width direction.

  In this method for constructing an upper suspension type slab bridge, since the container is suspended and supported below the precast concrete plate, the center of gravity between the precast concrete plate and the container containing water is lowered. In addition, when the suspended floor slab is inclined in the width direction, it is suspended from one of the suspension members stretched from both side edges toward the lower central part of the suspended floor slab, that is, from the side edge where the suspended floor slab is inclined and raised. The tension of the suspended material becomes larger than that of the suspended material stretched from the other side edge, and this is a force for correcting the inclination of the suspended floor slab. Thereby, even if the suspended floor slab is inclined in the width direction due to an uneven load of the load or the like, the inclination is suppressed by the container containing water.

  The invention according to claim 7 is the construction method of the upper suspension type slab bridge according to any one of claims 1 to 5, wherein a plurality of the containers are supported in the width direction of the precast concrete board. When the precast concrete board is inclined in the width direction, the amount of water in the container is adjusted, and the inclination in the width direction generated in the precast concrete board is made closer to horizontal.

  In the construction method of this upper-floor type suspended floor slab bridge, water is moved between a plurality of containers supported in parallel in the lateral direction of the precast concrete plate, water is poured into these containers or drained from these containers, The horizontal distribution of the weight of the loaded water can be changed. Thereby, it is possible to suppress a lateral displacement difference that occurs when an uneven load is applied to the suspended floor slab, that is, an inclination in a direction perpendicular to the bridge axis. Therefore, it is possible to prevent the suspended floor slab from overturning and twisting in the lateral direction.

  As described above, in the construction method of the upper-floor type suspended floor slab bridge of the invention according to the present application, from the side of the precast concrete plate supported by the cable stretched in a state in which the deflection between the abutment or the bridge pier is generated. It is possible to suppress the change in the viewed arrangement shape, that is, the shape in which the cable bends, greatly changes due to the loading of the load, and to construct the cable in a stable state.

It is a schematic side view which shows an example of the upper path type suspension floor slab bridge constructed | assembled by the method which concerns on this invention. It is sectional drawing of the upper-path-type suspension floor slab bridge shown in FIG. It is a side view which expands and shows the edge part of the upper-path-type suspension floor slab bridge shown in FIG. It is the schematic which shows the process of constructing the upper-path type suspension floor slab bridge shown in FIG. It is the schematic which shows the process of constructing the upper-path type suspension floor slab bridge shown in FIG. It is the schematic which shows the process of constructing the upper-path type suspension floor slab bridge shown in FIG. It is the schematic which shows the process of constructing the upper-path type suspension floor slab bridge shown in FIG. It is sectional drawing which shows the fixing state of the cable in erection. It is a schematic sectional drawing which shows the state which suspended and supported the precast concrete board with the 1st cable. It is a schematic sectional drawing which shows the state which mounted the container on the precast concrete board. It is the schematic for demonstrating adjustment of the amount of water in a container. It is the schematic for demonstrating adjustment of the amount of water in a container. It is the schematic for demonstrating adjustment of the amount of water in a container. It is a schematic sectional drawing which shows the example which suspended and supported the container on the precast concrete board. It is a schematic sectional drawing which shows the example which mounted the container in parallel in the width direction of the precast concrete board. It is a schematic side view showing a problem to be solved by the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic side view of an upper type suspended floor slab bridge that can be constructed by the method according to the present invention. FIG. 2 is a cross-sectional view of this upper suspension type slab bridge.
This upper suspension type slab bridge is constructed between two abutments 1 and 2, and concrete end blocks 3 and 4 supported on the abutments 1 and 2 through fences 5 and 6, respectively. A suspended floor slab 7 stretched between the end blocks 3 and 4, a plurality of columns 8 erected on the suspended floor slab 7, and the end blocks 3 and 4 are formed so as to be continuous, The main part is composed of the upper girder 9 supported on the suspended floor slab 7 by the support column 8.

  The abutments 1 and 2 are constructed of reinforced concrete on the solid ground 20 at the position where the bridge is constructed, and are firmly fixed to the ground 20 or the rock by the earth anchors 10 and 11 when constructed. After the suspended floor slab 7 and the upper girder 9 are completed, the earth anchors 10 and 11 are unnecessary and can be removed, but may be left as they are.

  As the ridges 5 and 6, rubber ridges, cast ridges or the like can be used. These eaves 5 and 6 support the girders so that they can rotate around a horizontal axis perpendicular to the axis of the bridge. And among the eaves 5 and 6 that support both ends of the girder, one restrains horizontal movement in the axial direction of the bridge, and the other permits movement. Horizontal movement in the direction perpendicular to the axis of the bridge is constrained on both ridges 5 and 6.

  The end blocks 3 and 4 may be made of cast-in-place concrete, or precast concrete that has been manufactured in advance at a factory or the like. The upper girder 9 continuous between both end blocks 3 and 4 is joined to the upper part of the vertical surfaces of these end blocks 3 and 4, and the suspended floor slab 7 is joined to the lower part. And both ends of the cable 12 (not shown in FIG. 1) for supporting the suspended floor slab 7 are fixed to these end blocks 3 and 4, respectively.

  The suspended floor slab 7 is formed so that a thin concrete plate-like member is continuous between the two end blocks 3 and 4, and is supported by the tensile force of the cable 12 in a state in which deflection occurs. . The suspended floor slab 7 is connected to a plurality of precast concrete plates 21 created in a production yard near the factory or the site, and between these and the precast concrete plates 21 and the end blocks 3 and 4. It is made of cast-in-place concrete.

The cable 12 includes a plurality of first cables 12a and a plurality of second cables 12b, and the first cable 12a is a precast concrete plate forming a suspended floor slab 7 as shown in FIG. Is supported in a groove 21a formed on the upper side of 21 and supports the precast concrete plate 21 via a steel rod 22 which is bridged on the upper side of the first cable 12a and fixed to the precast concrete plate 21. It has become. And concrete is cast in this groove | channel 21a, and the 1st cable 21a is embedded. As shown in FIG. 3, these first cables 12a can be fixed to the end blocks 3 and 4 of the concrete by screwing nuts 17a to the ends.
The second cable 12 b is inserted into a sheath 18 embedded in the concrete of the suspended floor slab 7, and both ends are also fixed to the end blocks 3 and 4.

The support column 8 is made of steel, and as shown in FIG. 1, is raised obliquely upward from the upper surface of the suspended floor slab 7 and is configured to support the upper road girder 9. And the support | pillars 8a and 8b which incline in the direction which becomes a mutually opposite side of a bridge axis direction are started from the adjacent position on the suspended floor slab 7, and these support | pillars 8 form a warren truss with the suspended floor slab 7 and the upper road girder 9. ing. As shown in FIG. 2, these struts 8 are raised from the vicinity of both side edges of the suspended floor slab 7, and their upper ends are connected to each other by a horizontal connecting member 19.
In addition, the support | pillar 8 can also use what consists of fiber reinforcement mortar or a synthetic resin.
Further, in this embodiment, the column 8 is formed to rise obliquely upward from the suspended floor slab 7, but may be formed substantially vertically from the suspended floor slab 7. That is, the column, the suspended floor slab, and the upper road girder may not have a truss structure.

The upper girder 9 is composed of a segment 23 made of precast concrete supported on the top of the column 8 and cast-in-place concrete that continues between the segments 23. And reinforcement with the reinforcing bar is made so that it can fully endure the bending moment and the shearing force due to its own weight or live load.
The upper girder 9 can also be formed by assembling a support work on the suspended floor slab 7 and placing concrete on site.

Next, it is one Embodiment of the invention which concerns on this application, Comprising: The method to construct | assemble the said upper-path type suspended floor slab bridge is demonstrated.
First, as shown in FIG. 4, abutments 1 and 2 are constructed on both sides of a position where the upper suspension type slab bridge is constructed. The abutments 1 and 2 are firmly fixed to the ground 20 or the rock by the earth anchors 10 and 11 so that they can resist a large horizontal force. Then, the end blocks 3 and 4 are supported on the abutments 1 and 2 via the flanges 5 and 6, and are temporarily fixed to the abutments 1 and 2.

Thereafter, the first cable 12 a is stretched between the two end blocks 3 and 4. The cable to be stretched here is only the first cable 12a. As shown in FIG. 8, the cable is inserted into the sheath embedded in the end block 3, and the extension cable 14 is connected to the abutments 1 and 2. To settle. The extension cable 14 can be connected by a coupler 13 to a fixing body 15 that is crimped to both ends of the first cable 12a. As a result, the reaction force acting from the first cable 12a during installation is borne on the abutment 1 so that the reaction force does not act on the end block 3. A nut 17a is screwed onto the fixing body 15, and a reaction force is applied to the end blocks 3 and 4 in the completed system to fix the cable 12a.
In addition, the rear part of the abutment 1 is reinforced by the PC steel material 16 in the vertical direction so that excessive tensile stress is not generated in the rear cross section of the abutment 1 when the reaction force from the extension cable 14 is applied.

Next, the precast concrete board 21 forming the suspended floor slab is suspended and supported by the first cable 12a. As shown in FIG. 9, the first cable 12a is supported by lifting the precast concrete plate 21 so that the cable 12a fits in the groove 21a provided on the upper side of the precast concrete plate 21, and short steel on the upper side of the cable 12a. This is done by locking the bar 22 to the precast concrete plate 21. The precast concrete board 21 moves along the cable while being locked to the cable 12a as described above, and is arranged in order from the position adjacent to the one end block 4.
Reinforcing bars (not shown) for connecting the precast concrete plates to each other are projected from both end faces of the precast concrete plate 21 in the axial direction of the suspended floor slab.

As shown in FIG. 5, when the precast concrete board 21 is arranged in almost the entire region between the end blocks 3 and 4, the container 30 is placed on the precast concrete board 21 in an empty state in order to store water. . Then, water is poured into these containers 30 as shown in FIG.
The container 30 can be made of various materials such as a synthetic resin, a drum can, and a waterproof bag-like member supported by a frame, but is preferably lightweight. Further, it is preferable that the upper portion is widely opened and water can be easily injected or discharged by a pump or the like. The water stored in these containers 30 is distributed in the axial direction of the first cable 12a, and for example, the same amount of water is stored in all containers. Moreover, although the amount of water may be changed for each container, it is preferable to determine the amount of stored water by distributing it so that the amount of water stored between adjacent containers does not vary greatly.
Note that FIG. 5 shows the container 30 in cross section to show the water stored in the container 30.

The amount of water stored in the container 30 is preferably equal to or greater than the load that is newly loaded on the precast concrete plate 21. In other words, it is desirable to store more water than the amount corresponding to the load of the segment 23 that constitutes the column 8 and the upper beam 9 provided on the precast concrete plate 21.
In the present embodiment, after the precast concrete plate 21 is arranged along the first cable 12a, the container 30 is placed and water is injected, but the container in which the water is stored is used as the precast concrete plate 21. It can be moved along the first cable 12a in a state of being placed on the top, and can be arranged at a predetermined position together with the precast concrete plate 21.

Next, the support column 8 is erected on the plurality of precast concrete plates 21.
As shown in FIG. 2, the support column 8 is raised from the vicinity of both side edges of the precast concrete plate 21. And as shown in FIG. 6, it makes it incline in the axial direction of a suspended floor slab, and a lower end part adjoins another support | pillar, and the upper end part adjoins the support | pillar different from the support | pillar adjacent at the lower end part. The upper ends of these columns 8 are connected in the axial direction of the bridge by a connecting member 25. Moreover, it is desirable to join these support | pillars 8 so that force may be transmitted with an adjacent other support | pillar by an upper end part or a lower end part. On the other hand, the lower end of the column 8 and the precast concrete plate 21 are joined by connecting the column 8 to an anchor (not shown) protruding from the surface of the precast concrete plate 21 and between the lower end of the column 8 and the precast concrete plate 21. Fill with concrete or mortar. By this hardening of the concrete or mortar, the precast concrete plate 21 and the support column 8 are integrated, and the force is transmitted between them.

Subsequently, as shown in FIG. 7, a precast concrete segment 23 to be the upper road girder 9 is arranged so as to be bridged between the tops of the columns 8. The segment 23 is arranged in such a manner that the connecting member 25 connecting the tops of the columns 8 is used as a rail, or a rail is laid on the connecting member 25 and travels on the rail 23 as shown in FIG. Are sequentially arranged from a position adjacent to the end block 4.
When one segment 23 is sent out and supported on the support column 8, the container placed on the precast concrete plate 21 positioned below the segment 23, that is, the precast concrete plate 21 on which the load of the arranged segment 23 acts. From 30, an amount of water corresponding to the weight of the segment 23 is discharged. In this manner, the segments 23 are sequentially arranged, and water is discharged from the container 30 placed on the precast concrete plate 22 at the position where the segments 23 are arranged, and the segments 23 are arranged between the end blocks 3 and 4. Array.
FIG. 7 shows the container 30 in cross-section to show the amount of water stored in the container 30.

Since the water is discharged in response to the load being loaded as described above, the influence of the new load being loaded is reduced. That is, when an amount of water corresponding to the weight of the newly loaded segment 23 is discharged, the total amount of load acting on the first cable 12a hardly changes. In addition, the distribution of the load acting on the first cable 12a by discharging water from the container 30 in the vicinity of the loaded position does not vary greatly. Therefore, the bending shape of the first cable 12a does not change greatly.
The amount of water to be discharged is not necessarily an amount corresponding to a newly loaded load, and even if the amount is slightly different, it is possible to suppress a significant change in the shape of the deflection. Further, in this embodiment, water is discharged from the container 30 on the precast concrete plate on which the segment 23 is disposed, but water is discharged from one or a plurality of containers disposed near the position where the segment 23 is disposed. There may be.

  After arranging the segments 23 constituting the upper girder 9 while discharging the water in the container 30 as described above, the segments 23 between the segments 23 and adjacent to the end blocks 3, 4 and the end blocks 3, 4 Concrete is placed between the upper blocks and the upper blocks 3 are formed between the end blocks 3 and 4. Further, concrete is placed between the precast concrete plates 21 supported along the first cable 12a and between the precast concrete plates 21 adjacent to the end blocks 3 and 4 and the end blocks 3 and 4. Thus, a suspended floor slab 7 continuous between the two end blocks 3 and 4 is formed.

As described above, when the upper girder 9 and the suspended floor slab 7 are continuous between the end blocks 3 and 4, the second cable 12 b inserted through the sheath 18 embedded in the precast concrete plate 21 is tensioned to the suspended floor slab 7 along the axis. Introduce direction prestress. Then, the second cable 12 b is fixed to the end blocks 3 and 4.
Further, the nut 17b that has locked the extension cable 14 connected to the first cable 12a to the abutments 1 and 2 is loosened, and the nut 17a screwed to the fixing body 15 at the end of the first cable 12a is used. The end blocks 3 and 4 are made to bear the tensile force of the first cable 12a. Then, when the temporary fixing of the end blocks 3 and 4 is released, the reaction force of the first cable 12 a is transmitted from the end blocks 3 and 4 to the upper beam 9 as an axial force. Thereby, it becomes a structure where both ends are simply supported as shown in FIG. That is, the tensile force acting on the suspended floor slab 7 and the compressive force acting on the upper girder 9 are offset, resulting in a so-called self-contained structure system in which no horizontal force acts on the abutments 1 and 2.

  As described above, when the suspended floor slab 7 is continuous between the end blocks 3 and 4 and the fixing position of the first cable 12a is changed and the structural system becomes independent from the abutments 1 and 2, it remains in the container 30. Drain the used water and remove the container. As a result, the sag of the suspended floor slab 7 is reduced, and prestress is further introduced into the suspended floor slab 7.

  In this way, the container 30 is supported on the precast concrete plate 21 supported by the first cable 12a, and a new load is applied while adjusting the amount of water stored in the container 30. The variation in deflection is reduced, and the upper girder 9 can be formed in a stable state. Moreover, the relative angle change and displacement between adjacent precast concrete boards 21, and the relative angle change and displacement between the segments 23 which comprise the upper road girder 9 can be suppressed small, the reinforcement etc. for connecting these, etc. Can be prevented, and the precast concrete plate 21 can be prevented from being damaged by the interference of the reinforcing bars.

In the above embodiment, the water in the container is discharged with the loading of a new load. However, as described below, the water in the container is moved to another container or poured into the container. You can also.
A first example of another method for injecting, discharging, or moving water to and from the container is as shown in FIG. In this description, the diagram is simplified and only the concept is shown.
In this example, it is assumed that six containers 31a, 31b, 31c, 31d, 31e, and 31f are supported in the axial direction of the bridge as shown in FIG. When the weight of each segment 32a, 32b, 32c, 32d, 32e, 32f for forming the upper girder is 6 (a numerical value indicating the magnitude of the load, no unit, hereinafter the same), The weight of the water stored in the container 31 is assumed to be 10. In this state where the water is stored in the container, the first segment 32a is arranged as shown in FIG.

  As shown in FIG. 11 (b), when the first segment 32a (corresponding to 6 loads) is arranged, the load equivalent amount from the container 31a placed near the position where the weight of the segment 32a acts as a load. The water 6 is discharged, and this water is distributed one by one to all the containers including the container 31a. That is, water corresponding to one load is transferred from the container 31a at the position where the weight of the segment 32a acts to all other containers. As a result, the weight of water in the container 31a is 5, and the weight of water in the other containers is 11. Further, the loaded load near the position where the container 31a is supported is 11, which is the sum of the segment 32a and water, and is the same as the loaded load near the position where the other containers 31b, 31c, 31d, 31e, 31f are placed, The axial load is maintained substantially uniform.

  Next, as shown in FIG. 11C, when the second segment 32b (corresponding to 6 loads) is arranged, water corresponding to 1 load is distributed from the container 31b to all the other containers 31. Thereby, the water weight of the container 31a and the container 31b is 6, and the weight of water in the other containers is 12. Further, the load acting near the position where the containers 31a and 31b are placed and the load acting near the position where the other containers 31c, 31d, 31e and 31f are placed are also 12 respectively. The weight is almost uniform.

  Thus, when it arranges in order to the last segment 32f, as shown in FIG.11 (d), since the weight of the water in each container 31 becomes 10 and the load of each segment 32 is 6, The load acting in the vicinity of the placed position is 16. As a result, the load in the axial direction of the suspended floor slab is substantially uniform during the placement of the segments and when the placement is completed, and the pre-cast concrete plates arranged along the cable are prevented from being deformed in the vertical direction. can do.

Next, a second example of another method for injecting, discharging, or moving water with respect to a container will be described.
In this example, when a load is loaded on one end side 41 from the center point 40 of the cable stretched as shown in FIG. 12, the load is stored in a container supported near the position where the load acts. The distributed water is distributed to the container arranged on the other end side 42 from the center point 40 to adjust the load balance in the axial direction of the suspended floor slab.

Also in this example, the number of containers 31 and segments 32 is the same, the weight of the segments is 6, and the weight of water stored in each container 31 is 10 before the segments 32 constituting the upper beam are arranged.
As shown in FIG. 12 (a), when the first segment 32a is arranged from one end side, the load equivalent amount 6 of the segment 32a is supported from the container 31a supported near the position where the load of the segment 32a acts. Approximately half of the water is discharged. Then, the discharged water is supplied to the containers 31d, 31e, and 31f arranged on the opposite side to the other end side 42, that is, the side on which the segment 32a is arranged with respect to the center point 40 of the cable. Of water. Thus, the weight of water in the container 31a is 7, the weight of the water in the containers 31b and 31c on the side 41 where the segment 32a is disposed from the center point 40 is 10, and the containers 31d and 31e on the other end side 42. , 31f has a water weight of 11. Accordingly, 33 load equivalent acts on the side where the segment 32a is arranged (one end side), and 33 load equivalent also acts on the other end side, resulting in a balanced state on the left and right.

  Similar to the arrangement of the first segment 32a, when the second and third segments 32b and 32c are arranged in order while adjusting the amount of water, they are arranged on one end side 41 as shown in FIG. The amount of water in each of the containers 31a, 31b, 31c is 7, and the weight of the water in the containers 31d, 31e, 31f on the other end side 42 is 13, respectively.

Next, as shown in FIG. 12 (c), when the fourth segment 32d located on the other end side 42 from the center point 40 is disposed, the load corresponding to the segment 32d from the container 31d is approximately ½. Of water, that is, 3 of water. The water is then distributed one by one to the containers 31a, 31b, 31c arranged on one end side 41. Thus, the weight of water in the containers 31a, 31b, and 31c is 8, the weight of water in the container 31d is 10, and the weight of water in the containers 31e and 31f is 13.
In this way, as shown in FIG. 12 (d), when the last segment 32 f is arranged, the amount of water in each container 31 is 10 and constant.

  In this method of adjusting the amount of water, the cable acts on the one end side 41 and the other end side 42 with reference to the center point 40 of the cable, both during and after the arrangement of the segments. The applied load, that is, the sum of the weight of water and the weight of the segments becomes substantially the same, and it is possible to suppress the occurrence of a biased deformation in the vertical direction in the axial direction of the cable supporting the precast concrete plate.

Subsequently, a third example of another method for injecting, discharging or moving water in the container will be described.
In this example, as shown in FIG. 13, when the segments 32 are sequentially constructed from one end side 41 from the cable center point 40, the other end side 42 of the other end side 42 is set with reference to the cable center point 40. Water corresponding to the load is poured into a container disposed at a symmetrical position, and the balance of the load applied in the axial direction of the cable is adjusted.

  Also in this example, the number of containers and segments is 6, and the weight of the segments is 6. And the weight of the water stored in each container 31 before arrange | positioning the segment 32 which comprises an upper girder may be arbitrary, and although the weight of water is set to 10 in the example shown in FIG. 13, in the empty state which does not store There may be.

As shown in FIG. 13 (a), when the first segment 32a is arranged, it corresponds to the load of the segment 23 in the container 31f at a position symmetrical to the position where the segment 32a is arranged with respect to the center point 40. Inject water with a weight of 6 minutes.
Subsequently, as shown in FIG. 13B, the second and third segments 32b and 32c are arranged in the same manner as described above, and are symmetrical with respect to the arrangement positions of these segments 32b and 32c with respect to the center point 40. Water of weight 6 corresponding to the load is poured into the containers 31e and 31d at the positions. As a result, the weight of the segment 32 and the water loaded on one end side 41 from the central point 40 and the weight of the water loaded on the other end side 42 from the central point 40 are both equivalent to 16 loads. It will be the same.

Next, as shown in FIG. 13C, when the fourth segment 32d located on the other end side 42 from the center point 40 is disposed, the container 31d and the center point 40 to which the load of the segment 32d acts are connected. Water equivalent to 6 loads is poured into the container 31c located at a symmetrical position as a reference.
When the arrangement of the segments 32 is completed while sequentially injecting water in this way, the weight of the water stored in each container becomes 16, as shown in FIG. And since the load of the segment 32 is 6, the applied load which acts on the position which has arrange | positioned each container becomes equivalent to 22 loads, and a load becomes substantially constant in the axial direction of a cable.
As described above, also in the adjustment of this example, the load on the one end side 41 and the other end side 42 from the center point 40 is almost the same from the time when the segment is arranged until the end of the arrangement. And the deformation | transformation of the up-down direction where the axial direction of the cable deviated can be suppressed.
In this example, as shown in FIG. 13C, when the fourth and subsequent segments 32d, 32e, and 32f are arranged on the other end side from the center point 40, the position is below the position where the segment is arranged. Water corresponding to the load of the segment 32 may be discharged from a certain container 31d, 31e, 31f. In such an adjustment, the weight of the water stored in each container when the arrangement of the segments 32 is completed is equivalent to 10 loads equivalent to before the arrangement of the segments 32 is started.

Four examples have been described above regarding the mode of injecting, discharging or transferring water, but the construction method of the upper-floor type suspension floor slab bridge of the present invention is not limited to these, and various methods can be used within the scope of the present invention. The method can be adopted.
In the embodiment described above, the amount of water in the container supported by the precast concrete plate 21 is adjusted when the segments 23 and 32 are erected, but the column 8 is erected on the precast concrete plate 21. Sometimes it can be done. Also in this case, by adjusting the amount of water according to the procedure described in the above four examples or other procedures, the occurrence of large deflection is suppressed even when the weight of the column acts sequentially, and the column 8 can be stably maintained. Standing is possible.

On the other hand, the container 30 may be installed on the precast concrete plate 21 after the support column 8 is erected on the precast concrete plate 21.
The support column 8 may be erected in advance on the precast concrete plate 21, and a unit composed of the precast concrete plate 21 and the support column 8 is supported by the first cable 12a and moved along the first cable 12a. Can also be arranged. In this case, you may move along the 1st cable 12a in the state which mounted the container 30 in which water was stored by the unit. Compared with the case where only the precast concrete board 21 is arranged, the unit provided with the support column 8 has a higher center of gravity, and the state in which the precast concrete board 21 is supported by the first cable 12a tends to be unstable. By placing the container 30 for storing water, the center of gravity is lowered, and stable movement and arrangement are possible.

  Further, the upper girder 9 is constructed by sequentially arranging the segments 23 of precast concrete, but can also be constructed by placing concrete on site. Also in the case of in-situ concrete, the amount of water in the container 30 supported by the precast concrete plate 21 is adjusted as the load of the cast concrete acts. Thereby, the load distribution of the axial direction of the 1st cable 12a can be adjusted, and it can suppress that the arrangement | sequence shape of the precast concrete board 21 when it sees from the side of the suspended floor slab 7 fluctuates.

  In the said embodiment, since it mainly demonstrated about the construction method of a self-supporting type suspension floor slab bridge, discharge | emission of water and removal of a container are after the suspension floor slab 7 and the upper road girder 9 continued between the end blocks 3 and 4. Going, prestress is introduced into the suspended floor slab 7. On the other hand, in the case of a suspended floor slab where the suspended floor slab is supported directly on the abutment and the upper girder is supported thereon, the suspended floor slab is formed so as to be continuous between the abutments where the cable is fixed. Later, drain the water and remove the container. Thereby, the amount of deflection of the suspended floor slab is reduced, and prestress can be introduced into the suspended floor slab.

  The discharge, injection, and movement of water in the container can be performed manually by an operator using a pump or the like, but the pump, injection valve, discharge valve, and the like can also be driven by computer control.

In the embodiment described above, the container 30 is placed on the precast concrete plate 21. However, as shown in FIG. 14, the container 30 is supported by suspension from the precast concrete plate 21, and is supported by suspension on the first cable 12a. It is also possible to increase the stability by lowering the center of gravity of the structure.
Further, as a method for suspending and supporting the container, as shown in FIG. 14, it is desirable to use two suspension members 26a and 26b having one end coupled to the vicinity of both side edges of the precast concrete board 21. These suspension members 26a and 26b are stretched obliquely downward toward the center in the width direction of the precast concrete plate 21, and the container 34 is suspended and supported at the center portion in the width direction. If the container 34 is suspended and supported in this way, and the water is stored in the container 34, the precast concrete plate 21 suspended and supported by the cable 12a has a width due to an uneven load or the like, as indicated by a virtual line in FIG. When inclined in the direction, the tension of the suspension members 26a and 26b changes. That is, the tension of the suspension material 26a coupled to the edge vicinity 21L that is inclined upward is increased, and the tension of the suspension material 26b coupled to the edge vicinity 21R is decreased. Thereby, the tension | tensile_strength of suspension material 26a, 26b acts so that the inclination of the precast concrete board 21 may be corrected, and the horizontal stability of the precast concrete board 21 by which the support | pillar etc. were started up improves.

On the other hand, as shown in FIG. 15, a plurality of containers 35a, 35b containing water can be placed on the precast concrete plate 21 in parallel in the width direction of the precast concrete plate, that is, in the direction perpendicular to the axis of the bridge. By adjusting the amount of water in the container 35 installed in this way, it is possible to adjust the lateral load and suppress the occurrence of a displacement difference at both edges.
For example, when the right side of the precast concrete plate 21 is tilted down due to an unbalanced load or the like, a part or all of the water in the container 35a placed on the right side is transferred to the container 35b placed on the left side. By moving, the left and right inclination can be eliminated. Further, the right / left inclination may be eliminated by injecting water into the container 35b placed on the left side and discharging the water in the container placed on the right side.

1, 2: Abutment, 3, 4: End block, 5, 6: Fence, 7: Suspended floor slab, 8: Post, 9: Upper girder,
10, 11: Earth anchor, 12: Cable, 12a: First cable, 12b: Second cable, 13: Coupler, 14: Extension cable, 15: Fixing body, 16: PC steel, 17: Nut, 18: A sheath embedded in a precast concrete plate, 19: a transverse connecting member,
20: Ground,
21: Precast concrete board, 22: Steel bar, 23: Segment, 25: Connecting member, 26: Hanging material,
30: Container, 31: Container, 32: Segment, 34, 35: Container
40: Center point of the cable 41: One end side of the cable 42: Other end side of the cable

Claims (7)

A suspended floor slab, which is a thin concrete plate-like member formed along a cable stretched between two opposing abutments or piers, and a column erected on this suspended floor slab, and supported on this column A method for constructing an upper-floor type suspension floor slab bridge having an upper girder,
Stretching cables between abutments or piers;
Arranging a plurality of precast concrete plates constituting the suspended floor slab along the cable, and supporting the cable;
Constructing the upper girder on all the precast concrete boards or a column erected from a plurality of selected precast concrete boards;
A step of placing concrete between the precast concrete plates to form the continuous suspended floor slab, and
The step of constructing the upper girder includes injecting water into all the precast concrete plates or a container supported by a plurality of selected precast concrete plates, with respect to an increase in load accompanying the construction of the upper girder, Suppressing the change in the array shape seen from the side of the plurality of precast concrete plates supported along the cable, with the step of discharging the water stored in the container or moving the water between the containers A construction method of an upper-floor type suspension floor slab bridge characterized by being performed.   The step of injecting water, discharging water or moving water between the containers corresponds to the loading of the load associated with the construction of the upper girder, and the inside of the container provided near the loading position of the load The construction method of the upper-floor type suspended floor slab bridge according to claim 1, wherein the water is moved to another container or discharged.   The step of injecting the water, discharging the water or moving the water between the containers corresponds to loading of a load accompanying the construction of the upper girder, and is at one end side from the central point in the axial direction of the cable. When the load is loaded, the water stored in the container on the end side where the load is loaded is moved to the container provided on the other end side from the center point, or the other end The method for constructing an upper-floor type suspended floor slab bridge according to claim 1, wherein water is poured into a container provided on the part side. After the step of constructing the upper girder, water shall remain in the container,
The discharge of the total amount of water stored in the container and the removal of the container are performed between a structure in which concrete is placed between the precast concrete plates and both ends of the cable supporting the precast concrete plates are fixed. The construction method for an upper-floor type suspended floor slab bridge according to any one of claims 1 to 3, wherein the method is performed after the continuous suspended floor slab is formed. The column is erected in advance on the precast concrete plate,
The precast concrete board is supported by the cable, the container storing water is supported by the precast concrete board, and the precast concrete board is moved along the cable and arranged at a predetermined position. A method for constructing an upper suspension type slab bridge according to any one of claims 1 to 4.   The precast concrete board is joined to the precast concrete board by a suspension member that is joined in the vicinity of both end edges in the width direction of the precast concrete board arranged along the cable and stretched obliquely downward toward a substantially central part in the width direction. 6. A method for constructing an upper-floor type suspended floor slab bridge according to any one of claims 1 to 5, wherein the upper-floor suspension floor slab bridge is suspended and supported at substantially the center in the width direction. A plurality of the containers are supported in the width direction of the precast concrete plate,
When the precast concrete board inclines in the width direction, the amount of water in the container is adjusted, and the inclination in the width direction generated in the precast concrete board is made closer to horizontal. The construction method of the upper-floor type suspension floor slab bridge described in any of the above.

Images