JP4191205B2 - Divided expansion and contraction device used for extended floor slab method - Google Patents

Description

  The present invention relates to a split-type telescopic device used in an extended floor slab method, and more particularly to a split-type telescopic device that takes into account the convergence of the shrinkage of reinforced concrete over time after construction in a reinforced concrete bridge. .

  Conventionally, in order to absorb expansion and contraction due to temperature changes of the bridge, a finger type expansion and contraction device was installed between the bridge girder and the abutment so that one finger was inserted and removed between the other fingers. An apparatus is known (see, for example, Patent Document 1).

In addition, the bottom plate made of reinforced concrete is arranged by shaping the roadbed on the earthwork side, a part of the bottom plate is received by the abutment, and the reinforced concrete made from the end on the bridge side is extended to the earthwork side on the bottom plate. There is also known a telescopic device used in an extended floor slab method in which an extended floor slab is disposed and an earth floor side tip of the extended floor slab is connected to an auxiliary floor slab placed on a bottom plate (for example, Patent Documents). 2).
JP 2000-073305 A JP 2004-084280 A

  In the invention described in Patent Document 1, since the telescopic device is provided between the bridge girder and the abutment, the central portion where both fingers are loosely inserted into each other is a cantilever beam, and an excessive load is applied, and the vehicle passes. At the same time, a shock occurs, which gives discomfort to the vehicle occupant and causes environmental problems due to noise. Moreover, when the expansion / contraction amount of the bridge girder is large, the expansion / contraction amount of the expansion / contraction device, that is, the length in which both fingers are loosely inserted must be increased, and there is a problem that the cost increases due to the enlargement of the expansion / contraction device.

  In the invention described in Patent Document 2, an expansion device is installed on the bottom plate on the earthwork side, and the load passes through the bottom plate so that the vehicle passes as compared with the finger-type expansion joint described in Patent Document 1. Since there are few shocks when doing so, the generation of noise can be suppressed, and the structure is simple and inexpensive. However, when the amount of expansion / contraction of the bridge girder is large, like the expansion joint described in Patent Document 1, there is a problem that the cost is increased due to the enlargement of the expansion / contraction device.

Here, reinforced concrete bridges begin to shrink after installation due to creep and drying of the reinforced concrete, and the shrinkage of the reinforced concrete converges in about three years after the construction. The conventional expansion and contraction device is designed and constructed not only to absorb the amount of expansion and contraction due to the temperature change of the bridge, but also to absorb the amount of contraction after the construction of the reinforced concrete.

  For example, in the calculation formula based on the road bridge specification (Japan Road Association), the amount of expansion and contraction is calculated as follows. The larger one of normal and earthquake (level 1 ground motion) is taken as the design expansion / contraction amount.

In the case of a prestressed reinforced concrete bridge (hereinafter referred to as PC bridge),
The amount of expansion / contraction due to temperature change = 0.4 × L1, the amount of expansion / contraction due to drying shrinkage = 0.1 × L1, the amount of expansion / contraction due to creep = 0.2 × L1, and the margin (Min10mm) = 0.2 × L2.
1. Normal expansion / contraction amount (ΔLT) is ΔLT = 0.4 × L1 + 0.1 × L1 × β + 0.2 × L1 × β + 0.2 × L2
Where L1: Stretch digit length L2: Basic stretch amount
β: Reduction factor
Drying shrinkage: From concrete placement to fitting installation
The material age is set to 2-3 months and is 0.5.

(Drying shrinkage is 20 ° C in terms of temperature)
Creep: From the introduction of prestress of the girder to the installation of the joint
Set 2-3 months and set 0.5.
2. The amount of earthquake expansion and contraction (ΔLE) is the movement amount of Level 1 ground motion calculated by the design of the bearing.

  Table 1 shows the design expansion and contraction of the PC bridge.

3. About PC Bridge Creep and Drying PC bridge bridge girders begin to shrink (stretch beam length x 0.3) after installation due to creep and dryness, and most of the shrinking action converges in approximately three years. However, as described above, the conventional expansion / contraction apparatus is designed and constructed by taking in the contraction corresponding to about 40% of the whole in advance.

  Therefore, in the case of a new bridge, a shrinkage expansion device that takes in creep and dryness in addition to temperature changes is necessary, and the cost is increased by that amount, and the shrinkage of reinforced concrete has converged over the years after construction. After that, the telescopic device becomes useless in size, and the generation of shock and noise when passing through the vehicle becomes large. In addition, bridge maintenance is maintained with more maintenance than necessary.

  Therefore, in the expansion and contraction device used for the extended floor slab method in the bridge made of reinforced concrete, the expansion and contraction device is designed and constructed to the minimum size in consideration of the amount of shrinkage of the reinforced concrete due to the passage of time after construction. Therefore, a technical problem to be solved arises, and the present invention aims to solve this problem.

The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is characterized in that a part of the bottom plate arranged on the roadbed on the earthwork side is received by the abutment and the bridge is placed on the bottom plate. An extended floor slab made of reinforced concrete extending from the end of the side to the earthwork side, connecting the earthwork side tip of the extended floor slab and the auxiliary floor slab placed on the bottom slab , and The expansion and contraction device has a plurality of joint parts, the main joint part on the bridge side and the sub-joint part on the earthwork side, and when the shrinkage of reinforced concrete converges over the years after construction, the expansion and contraction function of the sub joint part is stopped. Alternatively , the auxiliary floor slab is provided on the bridge side and connected to the extended floor slab, and the auxiliary auxiliary slab is provided on the earthwork side and connected to the bottom slab. A floor slab Consists intermediate auxiliary slab provided between the slab and the detachable auxiliary slab,
The movement auxiliary floor slab is formed integrally with the extension floor slab so as to be slidable in the direction of expansion and contraction of the bridge, the detachable auxiliary floor slab is fixed on the bottom slab, and the intermediate auxiliary floor slab is fixed to the movement auxiliary floor. Independently of the plate, the bottom plate is slidable in the direction of expansion and contraction of the bridge,
Further, the movable auxiliary floor slab and the intermediate auxiliary floor slab are connected by the main joint portion, and the extended auxiliary slab method is formed by connecting the removable auxiliary floor slab and the intermediate auxiliary floor slab by a sub-joint. In the split-type telescopic device,
The main joint part has a size capable of absorbing the amount of expansion and contraction due to the temperature change of the bridge, and the sub joint part has a size capable of absorbing the shrinkage amount of the reinforced concrete that converges over the years.
Inside the intermediate auxiliary floor slab provided between the main joint part and the sub-joint part, a control bar is embedded and fixed substantially horizontally and in the expansion and contraction direction of the bridge,
The bridge side of the control bar protrudes to the main joint part and is slidably inserted into the movement auxiliary floor slab, and the earthwork side of the control bar protrudes to the sub joint part to attach and detach the auxiliary floor. Freely slidably inserted into the plate,
Furthermore, a movement restriction portion is provided in the inside of the movement auxiliary floor slab and the inside of the removable auxiliary floor slab to push or pull the intermediate auxiliary floor slab while being engaged with or in contact with an end portion of the control bar. A split-type telescopic device used in the extended floor slab method is provided.

  According to this structure, from the construction to a certain period of time, both the main joint part and the sub-joint part absorb the expansion and contraction of the bridge girder due to the temperature change of the bridge and the shrinkage due to creep and drying of the reinforced concrete. When the bridge girder is extended due to the temperature rise of the bridge, the movement auxiliary floor slab is pushed together with the extension floor slab to the earthwork side, and the movement to the earthwork side, that is, the extension of the bridge girder is absorbed by the main joint part. When the extension amount of the bridge girder exceeds the absorption amount of the main joint part, the end of the control bar comes into contact with the movement restriction part inside the movement auxiliary floor slab and pushes the intermediate auxiliary floor slab toward the earthwork side. The remaining amount of extension is absorbed by the sub-joint.

On the other hand, when the bridge girder contracts due to a drop in the temperature of the bridge, the movement auxiliary floor slab is pulled together with the extension slab to the bridge side, and this movement toward the bridge side, that is, the contraction of the bridge girder is reduced in the main joint part or sub joint part. Absorb at one or both joints. When the shrinkage amount of the bridge girder exceeds the absorption amount of one of the joint parts, the end of the control bar is locked to the movement restriction part inside the movement auxiliary floor slab or the movement restriction part inside the removable auxiliary floor slab. The remaining contraction amount is absorbed by the other joint portion.

  Then, after a certain period of time has elapsed since the construction, when the shrinkage due to creep or drying of the reinforced concrete converges, the sub-joint portion having an absorption amount corresponding to the converged shrinkage amount becomes unnecessary. Therefore, the expansion / contraction function is stopped or discarded by fixing or removing the sub-joint portion. After that, only the main joint part absorbs the expansion and contraction of the bridge girder due to the temperature change of the bridge.

According to a second aspect of the present invention, the movement restricting portion has a space portion having a length corresponding to the amount of expansion and contraction of the bridge, and an expansion portion is formed at an end portion of the control bar so as to be in the space portion. The space part of the extended floor slab or the auxiliary floor slab is locked or abutted on the expanded portion of the control bar when the bridge girder is expanded and contracted, and the intermediate auxiliary floor slab is pushed and pulled. The split type expansion-contraction apparatus used for the extended floor slab method according to claim 1 or 2 is provided.

  According to this configuration, the movement restricting portion has a space portion having a length corresponding to the expansion / contraction amount of the bridge girder, and when the extension amount of the bridge girder due to the temperature rise of the bridge exceeds the absorption amount of the main joint portion, The expansion part of the end of the control bar comes into contact with the space part of the movement restriction part provided inside the movement auxiliary floor slab, and the intermediate auxiliary floor slab is pushed to the earthwork side integrally with the control bar, and the remaining extension amount is reduced. Absorb at the sub-joint.

  On the other hand, when the shrinkage amount of the bridge girder due to the temperature drop exceeds the absorption amount of either the main joint part or the sub-joint part, the expansion part provided at the end of the control bar is the moving auxiliary floor slab. Or it is locked in the space part of one of the movement restriction parts of the detachable auxiliary floor slab extension, the intermediate auxiliary slab is pulled to the bridge side integrally with the control bar, and the remaining shrinkage is absorbed by the other joint part .

Since the expansion / contraction device of the present invention has the above-described action , the expansion / contraction device can be designed and constructed to the minimum necessary size in consideration of the convergence of the shrinkage of the reinforced concrete, thereby reducing the cost of the expansion / contraction device. be able to. When the sub-joint portion is removed, the sub-joint portion can be reused at other construction sites.

  In addition, by making the telescopic device the minimum necessary size, the occurrence of shock and noise when passing through the vehicle is suppressed, and maintenance of bridges is also improved, contributing to simplification of maintenance. be able to.

Hereinafter, in the expansion and contraction device used for the extended floor slab method in the bridge made of reinforced concrete , the present invention takes into account the amount of contraction of the reinforced concrete due to the lapse of years after construction, and the expansion device is made to the minimum necessary size. In order to achieve the purpose of design and construction, a part of the bottom slab arranged on the roadbed on the earthwork side is received by the abutment and extended from the end on the bridge side to the earthwork side on the bottom slab. An extended floor slab made of reinforced concrete is disposed, the earthwork side tip of the extended floor slab is connected to the auxiliary floor slab placed on the bottom slab, and the expansion device is connected to the main joint portion on the bridge side and the earthwork side When the shrinkage of reinforced concrete converges over the years after construction, the expansion and contraction function of the sub-joint portion can be stopped or discarded. Further, the auxiliary floor slab is provided on the bridge side and connected to the extended floor slab, the removable auxiliary floor slab provided on the earthwork side and connected to the bottom slab, and the movement An intermediate auxiliary floor slab provided between the auxiliary floor slab and the removable auxiliary floor slab,
The movement auxiliary floor slab is formed integrally with the extension floor slab so as to be slidable in the direction of expansion and contraction of the bridge, the detachable auxiliary floor slab is fixed on the bottom slab, and the intermediate auxiliary floor slab is fixed to the movement auxiliary floor. Independently of the plate, the bottom plate is slidable in the direction of expansion and contraction of the bridge,
Further, the movable auxiliary floor slab and the intermediate auxiliary floor slab are connected by the main joint portion, and the extended auxiliary slab method is formed by connecting the removable auxiliary floor slab and the intermediate auxiliary floor slab by a sub-joint. In the split-type telescopic device,
The main joint part has a size capable of absorbing the amount of expansion and contraction due to the temperature change of the bridge, and the sub joint part has a size capable of absorbing the shrinkage amount of the reinforced concrete that converges over the years.
Inside the intermediate auxiliary floor slab provided between the main joint part and the sub-joint part, a control bar is embedded and fixed substantially horizontally and in the direction of expansion and contraction of the bridge,
The bridge side of the control bar protrudes to the main joint part and is slidably inserted into the movement auxiliary floor slab, and the earthwork side of the control bar protrudes to the sub-joint part to attach and detach the auxiliary floor. Freely slidably inserted into the plate,
Furthermore, a movement restriction portion is provided in the inside of the movement auxiliary floor slab and the inside of the removable auxiliary floor slab to push or pull the intermediate auxiliary floor slab while being engaged with or in contact with an end portion of the control bar. This was realized by providing a split-type telescopic device used in the extended floor slab method .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For the convenience of explanation, items related to the present invention will be explained at the same time. 1 is a longitudinal side view of a road constructed in the vicinity of a bridge portion, FIG. 2 is a plan view in which the description of a pavement is omitted, and a bridge girder 11 forming the bridge portion 10 is attached to an abutment 13 via a support 12. The bridge deck 14 is placed on the bridge girder 11. The earthwork section 15 arranges the bottom plate 17 on the compacted embankment 16, extends the end portion of the bottom plate 17 on the bridge portion 10 side so as to be received on the upper surface of the abutment 13, and fixes the end portion of the bottom plate 17 to the anchor. Secure with bolts 18. A gap 19 is provided between the bottom plate 17 and the bridge girder 11.

  An extended floor slab 20 is disposed on the bottom slab 17, and an end of the extended floor slab 20 on the bridge side is placed on the same plane as the bridge floor slab 14. Then, the cast-in-place concrete 22 is placed on the protruding portion of the menase hinge 21 embedded in the end of the extended floor slab 20 so that the extended floor slab 20 and the bridge floor slab 14 are integrally connected. The end of the extended floor slab 20 on the earthwork side is connected to an auxiliary floor slab 24 by a cotter-type joint 23, and an extension device 30 is provided on the auxiliary floor slab 24.

  The bottom plate 17 and the extended floor slab 20 are each formed by connecting a plurality of precast reinforced concrete plates, and the contact surface between the bottom plate 17 and the extended floor slab 21 is formed smoothly. A paved surface 40 is continuously constructed on the upper surface of the extended floor slab 20 from the bridge side, and a paved surface 40 is also constructed on the earthwork side end of the auxiliary floor slab 24. As will be described later, when the bridge girder 11 expands and contracts due to a temperature change on the bridge portion 10 side, the extended floor slab 20 connected to the bridge floor slab 14 is pushed and pulled by the bridge floor slab 14 and slides on the upper surface of the bottom slab 17. The expansion / contraction of the bridge girder 11 is absorbed by the expansion / contraction device 30.

  The auxiliary floor slab 24 is provided on the bridge side and connected to the extended floor slab 20 by the cotter-type joint 23, and the bottom slab 17 is provided on the earthwork side by another cotter-type joint 23. It comprises a connected detachable auxiliary slab 27 and an intermediate auxiliary slab 26 provided between the movable auxiliary slab 25 and the detachable auxiliary slab 27. The expansion device 30 includes a main joint 31 on the bridge side and an earthwork. It is divided into a plurality of joint portions with the side sub-joint portion 32.

  3 and 4 show the main parts of the auxiliary floor slab and the expansion device, and the auxiliary floor slab 24 and the expansion device 30 will be described with reference to FIG.

  First, the auxiliary floor slab 24 will be described. As described above, the auxiliary floor slab 24 includes the movement auxiliary floor slab 25 provided on the bridge side, the attachment / detachment auxiliary floor slab 27 provided on the earthwork side, the movement auxiliary floor slab 25 and the attachment / detachment auxiliary floor slab 27. It is composed of an intermediate auxiliary floor slab 26 provided therebetween. The movement auxiliary floor slab 25 is formed integrally with the extended floor slab 20 so as to be slidable on the bottom plate 17 in the direction of expansion and contraction of the bridge, and the detachable auxiliary floor slab 27 is fixed on the bottom plate 17 and does not slide. The intermediate auxiliary floor slab 26 is connected to the moving auxiliary floor slab 25 on the bridge side via the main joint portion 31, and is connected to the removable auxiliary floor slab 27 on the earthwork side via the sub joint portion 32. Therefore, the intermediate auxiliary floor slab 26 is formed to be slidable on the bottom plate 17 independently of the movement auxiliary floor slab 25.

  Inside the intermediate auxiliary floor slab 26, a control bar 33 is embedded and fixed substantially horizontally and in the direction of expansion and contraction of the bridge, and is aligned with the axis of the control bar 33 so that the inside of the movement auxiliary floor slab 25 and A sheath tube 34 is formed inside the detachable auxiliary floor slab 27, and a space portion 35 communicating with the sheath tube 34 is formed.

Then, the bridge side of the control bar 33 is protruded to the main joint portion 31 and is slidably inserted into the sheath tube 34 of the movement auxiliary floor slab 25, and an expansion portion 36 is formed at the tip of the control bar 33 to move. It is stored in the space 35 of the auxiliary floor slab 25. Further, the earthwork side of the control bar 33 is protruded to the sub-joint portion 32 and is slidably inserted into the sheath tube 34 of the auxiliary slab floor 27, and an expansion portion 36 is formed at the tip of the control bar 33 to be attached and detached. It is stored in the space 35 of the auxiliary floor slab 27.

  As will be described later, when the moving auxiliary floor slab 25 slides on the bottom slab 17 integrally with the extended floor slab 20 due to the expansion and contraction of the bridge girder 11 due to the temperature change of the bridge, the expanded portion provided at the end of the control bar 33 When 36 and the space part 35 can move relatively in the expansion and contraction direction of the bridge, the intermediate auxiliary floor slab 26 can freely slide relative to the movement auxiliary floor slab 25 or the detachable auxiliary floor slab 27. In other words, the intermediate auxiliary floor slab 26 can be kept in a stopped state against the pushing and pulling of the movement auxiliary floor slab 25, or the intermediate auxiliary floor slab 26 can approach or separate from the fixed removable auxiliary floor slab 27.

  On the other hand, the expanded portion 36 provided at the end portion of the control bar 33 is in contact with or locked to the end surface on the back side of the space portion 35 or the end surface on the sheath tube 34 side, so that the When the intermediate auxiliary floor slab 26 cannot move freely, the intermediate auxiliary floor slab 26 cannot slide freely with respect to the movement auxiliary floor slab 25 or the removable auxiliary floor slab 27. That is, the intermediate auxiliary floor slab 26 moves integrally with the push of the moving auxiliary floor slab 25, or the intermediate auxiliary floor slab 26 approaches or separates further from the fixed detachable auxiliary floor slab 27. Can not.

  Thus, the movement restricting portion 37 that restricts the movement of pushing and pulling of the intermediate holding floor slab 26 with the space portion 35 and the expanded portion 36 of the control bar 33 accommodated in the space portion 35 is provided. It is configured. In this embodiment, the box-shaped movement restriction unit 37 is used. However, the movement restriction unit 37 should not be limited to this, and a movement restriction unit having another shape may be used.

  Next, the telescopic device 30 will be described. As described above, the expansion / contraction device 30 is divided into a plurality of joint portions including a main joint portion 31 on the bridge side and a sub joint portion 32 on the earthwork side. From the time of construction to the passage of a certain period of time, both the main joint portion 31 and the sub-joint portion 32 exhibit the expansion / contraction function, and absorb the expansion / contraction of the bridge girder 11 due to the temperature change of the bridge and the shrinkage due to creep or drying of the reinforced concrete.

  Thus, since the expansion / contraction amount of the bridge girder 11 is distributed to the plurality of joint portions, the sub-joint portion 32 has a structure that can withstand short-term use until the shrinkage of the reinforced concrete converges. Well, the amount of expansion and contraction and shape can be designed and constructed on a small scale. Accordingly, the sub-joint portion 32 has both a stretchable portion 32a on the intermediate auxiliary floor slab 26 side and a stretchable portion 32b on the removable auxiliary floor slab 27 side formed in a small size.

  On the other hand, after the contraction of the reinforced concrete has converged, the main joint portion 31 only needs to have an amount of expansion / contraction enough to absorb the expansion / contraction of the bridge girder 11 due to the temperature change of the bridge, and is formed smaller than the conventional expansion / contraction device. Yes.

  In the example of illustration, the expansion / contraction part 31a by the side of the movement auxiliary floor slab 25 of the main joint part 31 may be made of steel, and the expansion / contraction part 31b by the side of the intermediate auxiliary floor slab 26 may be made of steel or concrete. Further, the main joint portion 31 has a deep comb tooth shape, and the sub joint portion 32 has a shallow concrete tooth shape.

  As the shape of the expansion / contraction device 30, in addition to the shape described above, as shown in FIG. 5, both the main joint portion 31 and the sub-joint portion 32 may have a comb-tooth shape that is deeply engaged. In the illustrated example, the sub-joint portion 32 is made of steel, and is formed so as to be removed after a certain period of time from construction and reused in another place. In addition, although illustration is omitted, the sub-joint portion 32 may be configured by an embedded joint portion.

  Here, a state where both the main joint part 31 and the sub joint part 32 exhibit an expansion / contraction function from construction to a certain period of time will be described with reference to FIGS.

  FIG. 6 shows a state where the bridge girder 11 is contracted and the movement auxiliary floor slab 25 is pulled to the bridge side integrally with the extended floor slab 20 because the temperature is low in winter. In this state, the movement restricting portion 37 in the movement auxiliary floor slab 25 is configured such that the expansion portion 36 provided at the end portion of the control bar 33 is locked to the end surface of the space portion 35 on the sheath tube 34 side, and the main joint portion. 31 is extended to the maximum.

  Similarly, the movement restricting portion 37 in the detachable auxiliary floor slab 27 is also secured to the end surface of the space portion 35 on the side of the sheath tube 34 by the expanded portion 36 provided at the end portion of the control bar 33, so that the sub-joint portion 32 is extended to the maximum.

  For convenience of explanation, in the illustrated example, both of the expanded portions 36 on both sides of the control bar 33 abut on the end surface of the space portion 35 on the side of the sheath tube 34, and both the main joint portion 31 and the sub joint portion 32 are at the longest positions. The telescopic device 30 cannot absorb the contraction amount of the bridge girder 11 any more, but actually, the maximum contraction amount of the bridge is calculated in advance at the design stage, and the bridge girder 11 It is necessary to provide a sufficient amount of expansion / contraction so that the expansion / contraction device 30 does not extend to the longest position even during maximum contraction.

  FIG. 7 shows a state where the bridge girder 11 is extended from the winter season and the movement auxiliary floor slab 25 is pushed to the earthwork side little by little together with the extended floor slab 20 because the temperature rises in the spring. When the movement auxiliary floor slab 25 is pushed to the earthwork side, the movement restricting portion 37 in the movement auxiliary floor slab 25 is such that the expanded portion 36 provided at the end of the control bar 33 faces the end surface on the far side of the space 35. The main joint portion 31 contracts and absorbs the extension amount of the bridge girder 11.

  In the example of illustration, the expansion part 36 of the control bar 33 is contact | abutted to the end surface of the back side of the space part 35, and the main joint part 31 is shrink | contracted to the minimum. Further, the movement restricting portion 37 in the detachable auxiliary floor slab 27 is such that the expanded portion 36 provided at the end portion of the control bar 33 is located near the end surface of the space portion 35 on the sheath tube 34 side, and the sub joint portion 32 is Almost no contraction. Therefore, the expansion / contraction device 30 still has a contraction amount and can absorb the extension of the bridge girder 11 due to the temperature rise.

  FIG. 8 shows a state in which the temperature rises to the maximum temperature in the summer, and the bridge girder 11 extends further than in the spring, and the movable auxiliary slab 25 is pushed to the earthwork side to the maximum with the extended floor slab 20. ing. In the state shown in FIG. 7, since the main joint portion 31 is contracted to the minimum, when the movement auxiliary floor slab 25 is further pushed to the earthwork side, the intermediate auxiliary floor slab 26 moves via the main joint portion 31. The movement restricting portion 37 in the detachable auxiliary floor slab 27 moves integrally with the auxiliary floor slab 25, and the expansion portion 36 provided at the end of the control bar 33 is on the end surface on the far side of the space portion 35. The sub-joint portion 32 contracts and absorbs the extension amount of the bridge beam 11.

  For convenience of explanation, in the illustrated example, both the expanded portions 36 on both sides of the control bar 33 are in contact with the end face on the back side of the space portion 35, and both the main joint portion 31 and the sub joint portion 32 contract to the shortest position. However, the telescopic device 30 cannot absorb the extension amount of the bridge girder 11 any more, but in reality, the extension amount of the bridge is calculated in advance at the design stage, and the maximum extension of the bridge girder 11 is achieved. However, it is necessary to provide a sufficient amount of expansion / contraction so that the expansion / contraction device 30 does not contract to the shortest position.

FIG. 9 shows a state in which the temperature is lowered in the autumn, the bridge girder 11 is contracted more than in the summer, and the movement auxiliary floor slab 25 is pulled little by little toward the bridge side integrally with the extended floor slab 20. When the movement auxiliary floor slab 25 is pulled to the bridge side, either one of the main joint part 31 or the sub-joint part 32 or both joint parts are gradually extended to absorb the contraction amount of the bridge girder 11. .

  That is, the expansion portion 36 provided at the end of the control bar 33 of one or both of the movement restriction portion 37 in the movement auxiliary floor slab 25 and the movement restriction portion 37 in the attachment / detachment auxiliary floor slab 27 is the space portion 35. It moves relatively toward the end surface on the side of the sheath tube 34, and either the main joint portion 31 or the sub-joint portion 32, or both joint portions extend to absorb the contraction amount of the bridge girder 11. .

In this way, both the main joint part 31 and the sub-joint part 32 exhibit the expansion / contraction function until a certain period of time (approximately three years) from construction, and the expansion / contraction of the bridge girder 11 due to the temperature change of the bridge and the creep of the reinforced concrete Absorbs shrinkage caused by drying. Then, when the contraction of the reinforced concrete converges after a certain period of time has elapsed from the construction, the concrete is placed and fixed in the space between the sub-joint portion 32 and the movement restricting portion 37, and the expansion / contraction function is stopped. Alternatively, part or all of the sub-joint portion 32 is removed and discarded. Thereafter, only the main joint portion 31 absorbs the expansion and contraction of the bridge girder 11 due to the temperature change of the bridge.

  By dividing the expansion / contraction device 30 into a plurality of joint portions of the main joint portion 31 and the sub-joint portion 32, the expansion / contraction device can be designed and constructed to the minimum necessary size, and the cost of the expansion / contraction device can be reduced. it can. By making the telescopic device the minimum necessary size, the occurrence of shock and noise when passing through the vehicle is suppressed, and maintenance of bridges can be improved and maintenance can be simplified.

  The expansion device 30 of the present invention is installed on the bottom plate on the earthwork side. The joint portion of each of the main joint portion 31 and the sub-joint portion 32 has a so-called load transmission type configuration in which the auxiliary floor slab supports the portion where one of the elastic portions is loosely inserted into the other elastic portion. It has become. Therefore, higher strength than the conventional finger type expansion and contraction device provided between the bridge girder and the abutment can be obtained, and less steel weight is used than before. In the present invention, since it is a split type expansion / contraction device, each expansion / contraction device can be miniaturized and the steel weight can be further reduced.

  Table 2 below shows the results of steel weight comparison caused by the difference in the structure of the expansion and contraction device in the PC bridge.

  However, only the face plate on the bridge side is included in the weight of the telescopic device. Moreover, since the hybrid system is adopted in the case of the split type, the left and right shapes and materials of the telescopic device are not necessarily the same. For example, the bridge side may be made of steel and the earthwork side may be made of concrete.

  As described above, the expansion / contraction device according to the present invention, which is a load transmission type and a division type, compared to the conventional type in which the expansion / contraction device is configured by one joint portion, can reduce the overall steel weight and reduce the cost. Can contribute to down. In addition, after the contraction of the reinforced concrete has converged after a certain period of time has elapsed from the construction, only the main joint portion 31 is left, so the scale of the expansion and contraction device can be reduced, and the vehicle travelability and environmental aspects can be reduced. The invention exhibits various effects such as quietness and easy management.

  It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

The longitudinal section side view of the road near the bridge part provided with the expansion-contraction apparatus which concerns on this invention. The top view which abbreviate | omitted description of the pavement surface of the road shown in FIG. Explanatory drawing which shows the principal part of the expansion-contraction apparatus which concerns on this invention. Explanatory drawing which shows the principal part of the expansion-contraction apparatus which concerns on this invention. Explanatory drawing which shows the modification of the expansion-contraction apparatus which concerns on this invention. Explanatory drawing which shows operation | movement of the expansion-contraction apparatus which concerns on this invention. Explanatory drawing which shows operation | movement of the expansion-contraction apparatus which concerns on this invention. Explanatory drawing which shows operation | movement of the expansion-contraction apparatus which concerns on this invention. Explanatory drawing which shows operation | movement of the expansion-contraction apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bridge part 11 Bridge girder 13 Abutment 14 Bridge floor slab 15 Earthwork part 17 Bottom slab 20 Extension floor slab 24 Auxiliary floor slab 25 Movement auxiliary floor slab 26 Intermediate auxiliary floor slab 27 Detachable auxiliary floor slab 30 Stretcher 31 Main joint part 32 Sub joint part 33 Control bar 34 Sheath tube 35 Space part 36 Expansion part 37 Movement restriction

Claims (2)

A part of the bottom slab arranged on the roadbed on the earthwork side is received by the abutment, and an extended floor slab made of reinforced concrete extending from the end on the bridge side to the earthwork side is arranged on the bottom slab, and the extension floor Connecting the earthwork side tip of the plate and the auxiliary floor slab placed on the bottom plate , and the expansion device has a plurality of joint portions of a main joint portion on the bridge side and a sub-joint portion on the earthwork side When the shrinkage of the reinforced concrete converges over the years after construction, the sub-joint part can be stopped or discarded , and the auxiliary floor slab is provided on the bridge side and the extension floor A movement auxiliary floor slab connected to the plate, a removable auxiliary floor slab provided on the earthwork side and connected to the bottom plate, and an intermediate auxiliary floor provided between the movement auxiliary floor slab and the removable auxiliary floor slab Version and
The movement auxiliary floor slab is formed integrally with the extension floor slab so as to be slidable in the direction of expansion and contraction of the bridge, the detachable auxiliary floor slab is fixed on the bottom slab, and the intermediate auxiliary floor slab is fixed to the movement auxiliary floor. Independently of the plate, the bottom plate is slidable in the direction of expansion and contraction of the bridge,
Further, the movable auxiliary floor slab and the intermediate auxiliary floor slab are connected by the main joint portion, and the extended auxiliary slab method is formed by connecting the removable auxiliary floor slab and the intermediate auxiliary floor slab by a sub-joint. In the split-type telescopic device,
The main joint part has a size capable of absorbing the amount of expansion and contraction due to the temperature change of the bridge, and the sub joint part has a size capable of absorbing the shrinkage amount of the reinforced concrete that converges over the years.
Inside the intermediate auxiliary floor slab provided between the main joint part and the sub-joint part, a control bar is embedded and fixed substantially horizontally and in the expansion and contraction direction of the bridge,
The bridge side of the control bar protrudes to the main joint part and is slidably inserted into the movement auxiliary floor slab, and the earthwork side of the control bar protrudes to the sub joint part to attach and detach the auxiliary floor. Freely slidably inserted into the plate,
Furthermore, a movement restricting portion is provided in the inside of the movement auxiliary floor slab and in the attachment / detachment auxiliary floor slab to push or pull the intermediate auxiliary floor slab while being engaged with or in contact with an end portion of the control bar. A split-type telescopic device used in the extended floor slab method. The movement restricting portion has a space portion having a length corresponding to the amount of expansion and contraction of the bridge girder, and forms an expansion portion at an end portion of the control bar to be accommodated in the space portion,
The space part of the movement auxiliary floor slab or the detachable auxiliary floor slab is formed to push or pull the intermediate auxiliary floor slab by engaging or abutting with the expanded portion of the control bar when the bridge girder is expanded or contracted. The split-type expansion-contraction apparatus used for the extended floor slab method of Claim 1 .

Images