1. Technical Field
The present invention relates to a rigid connection structure of each end of a concrete girder and a bridge pier of a rigid-frame bridge.
2. Background Art
Japanese Patent Application Laid-Open 2007-211566 discloses a rigid-frame bridge in which a concrete bridge pier and each end of a steel girder are rigidly connected via connection by a connection strip member and connection concrete. Here, the steel girders formed of shaped-steel such as H-shaped steel are arranged in parallel in the bridge width direction and each end of the steel girder is supported on a bridge abutment face of a concrete bridge pier. Further, each end of each steel girder is connected to a connection strip member arising from a bridge abutment face of the bridge pier, and then, each end of the steel girder is buried in the connection concrete by additionally casting the connection concrete on the bridge abutment face.
Bridge construction using steel girders constituted with shaped-steel such as H-shaped steel which causes overspending of steel material has been restricted for actualization in view of profitability as a result of recent escalating prices of steel material.
Further, shape selection of shaped-steel corresponding to an individual bridge is difficult because of difficulty of shape changing thereof.
In contrast, a precast concrete girder (PC concrete girder) is extremely inexpensive compared to a steel girder and is capable of being formed in arbitrary shaped easily in accordance with bridge design.
The present invention provides a rigid connection structure of a bridge pier and a concrete girder capable of providing robust rigid connection of each end of the concrete girder and the bridge pier while utilizing the concrete girder as a bridge girder.
In the present invention, a joint-equipped precast concrete girder (a joint-equipped PC concrete girder) constituted by burying a rear half part of a shaped-steel joint formed of short shaped-steel respectively in both ends of a concrete girder and being protruded a front half part of each shaped-steel joint from each end face of the concrete girder is previously prepared.
Here, the front half part and the rear half part are not limited to respectively have half length, as including a case that one is long and the other is short.
The joint-equipped PC concrete girders are carried to a construction site. Shaped-steel joint portions protruded from the respective concrete girder are supported on a bridge abutment face of a bridge pier while arranging the joint-equipped PC concrete girders in parallel in the bridge width direction.
Then, the rigid connection structure of the bridge pier and the concrete girders is formed by connecting the respective shaped-steel joint portions protruded from the respective end faces of the concrete girders to each connection strip member arising from the bridge abutment face of the bridge pier and burying the respective shaped-steel joint portions and the connection strip members in connection concrete which is additionally cased on the bridge abutment face.
The connection strip member is inserted through a flange of each shaped-steel joint portion and a nut is fixed on the flange as being screwed to an insertion end of the connection strip member. The nut is also buried in the connection concrete.
Instead of connecting with a nut, the shaped-steel joint portion and the connection strip member may be connected by welding or utilizing a connection clasp such as a wedge. The nut, welding and the connection clasp have a stopper function to prevent separation of the shaped-steel joint portion from the connection strip member.
A lateral connecting strip member is inserted through the respective shaped-steel joint portions protruded from the concrete girders and the shaped-steel joint portions of the adjacent concrete girders are mutually connected via the lateral connecting strip member. The lateral connecting strip member is buried in the connection concrete as well.
As described above, the concrete girder and the connection concrete are integrally structured via the shaped-steel joint by burying a rear half part of the shaped-steel joint in concrete at an end portion of the concrete girder and burying a front half part of the shaped-steel joint in the connection concrete.
The present invention includes an embodiment to indirectly receive the concrete girder as the respective shaped-steel joint portions protruded from end faces of the concrete girders being received on the bridge abutment face of the bridge pier and an embodiment to directly receive each end of the concrete girders on the bridge abutment surface as the respective shaped-steel joint portions being received on the bridge abutment face of the bridge pier.
According to the present invention, bridging cost can be drastically reduced compared to a rigid-frame bridge using the above steel girders and total quantity of steel material can be reduced. Further, concrete girders can be flexibly formed into a shape in accordance with a bridging site without shape restriction for steel girders.
In addition, concrete quantity for casting to a space between girders at the site can be reduced and casting operation can be lightened.
In the following, preferable embodiments will be described with reference to
The joint-equipped PC concrete girder 1 of each embodiment is provided with a pair of shaped-steel joints 3 formed of short shaped-steel at respective ends of the concrete girder 2.
The joint-equipped PC concrete girder 1 is formed as a rear half part of each shaped-steel joint 3 formed of the short shaped-steel being buried in each end portion of the concrete girder 2 and a front half part of each shaped-steel joint 3 being protruded from each end face of the concrete girder 2.
Specifically, a shaped-steel joint portion 3a being a rear half part of the first shaped-steel joint 3 is buried in the concrete girder 2 at one end thereof. A shaped-steel joint portion 3b being a front half part of the first shaped-steel joint 3 is protruded from a face of the one end of the concrete girder 2.
Similarly, a shaped-steel joint portion 3a being a rear half part of a second shaped-steel joint 3 is buried in the concrete girder 2 at the other end thereof. A shaped-steel joint portion 3b being a front half part of the second shaped-steel joint 3 is protruded from a face of the other end of the concrete girder 2.
Here, the front half part and the rear half part in the above are not intended to denote respective parts having half length of the shaped-steel joint 3, but rather includes a case that one is long and the other is short.
Plural through holes 8a penetrating a web 6 in the bridge width direction are arranged at the shaped-steel joint portion 3b protruded from the end face of the concrete girder 2. The through holes 8a are used for insertion of lateral connecting strip members 7 which are described later.
Further, plural through holes 8b penetrating a flange 10 of the shaped-steel joint portion 3b in the vertical direction are arranged. The through holes 8b are used for insertion of connection strip members 13 which are described later.
Meanwhile, plural through holes 8a penetrating the web 6 in the bridge width direction are arranged at the shaped-steel part 3a which is buried in the end portion of the concrete girder 2. Reinforcing rebars 16 are inserted in the through holes 8a and the reinforcing rebars 16 are buried in the concrete girder 2.
The reinforcing rebars 16 may be buried in the concrete girder 2 as short straight rebars being inserted respectively through the through holes 8a or a rebar longer than the above being bent in the longitudinal direction of the concrete girder 2 while being inserted through the respective through holes 8a.
In the first embodiment illustrated in
The through holes 8b are arranged at the upper and lower flanges 10 in the case that the shaped-steel joint 3 is formed of H-shaped steel.
Further, as an example, as illustrated in
Next, in the second embodiment illustrated in
In the second embodiment, the shaped-steel joints 3 at one end and the other end of the concrete girder 2 are respectively formed of two pieces of the C-shaped steel 3. The two pieces of C-shaped steel 3 are buried side by side as being mutually distanced in respective end portions of the concrete girder 2 in a state that the webs 6 are parallel and the flanges 10 are protruded toward outer sides.
Next, in the third embodiment illustrated in
In the T-shaped steel, the flanges 10 thereof are buried in the flanges 9 of the T-shaped concrete girder 2 and the web 6 of the T-shaped steel is buried in the web 11′ of the T-shaped concrete girder 2.
Not limited to the H-shaped steel, the T-shaped steel and the C-shaped steel illustrated in the above respective embodiments, the present invention includes a case of utilizing shaped-steel having any of various types of sectional shape such as I-shaped steel, L-shaped steel and Z-shaped steel as the shaped-steel joint 3. Then, various types of shaped-steel can be selectively utilized in accordance with the shape of the concrete girder 2.
As the various types of shaped steel, it is also possible to utilize shaped-steel having the various types of shapes by welding a flange plate to a web plate as well as utilizing shaped-steel extrudate due to JIS and the like.
The joint-equipped PC concrete girders 1 described in the first to third embodiments are utilized as being manufactured in a factory and carried to a bridge construction site.
Here, the inverted U-shaped reinforcing rebar 23 described in the first embodiment may be also utilized in the second and third embodiments of the joint-equipped PC concrete girder 1. That is, the inverted U-shaped reinforcing rebar 23 may be buried in the concrete girder 2 as being inserted through the flange 10 of the shaped-steel joint 3a as straddling the web 6 even when the C-shaped steel (in the second embodiment) or the T-shaped steel (in the third embodiment) are utilized as the shaped-steel joints 3.
In the following, a rigid connection structure of the bridge pier 4 and the concrete girder 2 by utilizing the joint-equipped PC concrete girder 1 will be described with reference to
The below-described rigid connection structure of the joint-equipped PC concrete girder 1 and the bridge pier 4 can be actualized in a single span rigid-frame bridge which is illustrated in
The concrete girders 2 are arranged in parallel in the bridge width direction while supporting the shaped-steel joint portion 3b protruded from the concrete girder 2 on a bridge abutment face 12 of the bridge pier 4.
Next, the respective shaped-steel joint portion 3b is connected to the connection strip member 13 arising from the bridge abutment face 12. For a specific example, a nut 17 is screwed to the connection strip member 13. Then, the lateral connecting strip member 7 is inserted therethrough and the connection concrete 14 is casted to the upper face of the bridge abutment face 12.
As described above, the rear half part of the shaped-steel joint 3 is buried in the concrete at the end portion of the concrete girder 2 and the front half part of the shaped-steel joint 3 is buried in the connection concrete 14. Accordingly, the concrete girder 2 and the connection concrete 14 are integrally structured via the shaped-steel joint 3.
The connection stripe member 13 being formed of a steel bar such as a rebar, for example, arises from the bridge abutment face 12 having the lower end of the steel bar buried integrally with the concrete bridge pier 4. Alternatively, it is possible to utilize a cable instead of the steel bar.
When the steel bar is utilized for the connection strip member 13, an end portion of a reinforcing rebar 15 buried in the concrete bridge pier 4 is protruded upward from the bridge abutment face 12, thereby forming the steel bar (i.e., the connection strip member 13) with the protruded portion.
The connection strip member 13 is inserted through the through hole 8b arranged at the flange 10 of the shaped-steel joint portion 3b. The nut 17 is screwed to the protruded end (i.e., a male thread of the protruded end) of the connection strip member 13 protruded from the upper face of the flange 10. Then, the shaped-steel joint portion 3b is connected to the bridge pier 4 as fixing the nut 17 on the upper face of the flange 10.
The nut 17 has a stopper function to prevent the shaped-steel joint portion 3b from floating. It is also possible to utilize a wedge or a retaining clasp having the stopper function.
In the case that the shaped-steel joint 3 is formed of H-shaped steel, the connection strip member 13 is inserted through the upper and lower flanges 10 of the shaped-steel joint portion 3b and the nut 17 is fixed on the upper face of the upper flange 10 as being screwed to the upper portion of the connection strip member 13.
The nut 17 is directly fixed on the upper face of the flange 10 or is fixed on the upper face of the flange 10 via pressure bearing member 18.
The pressure bearing member 18 is arranged as being extended across the shaped-steel joint portions 3b in the bridge width direction which is arranged in parallel in the bridge width direction to be arranged on the upper face of the flanges 10 of the respective shaped-steel joint portions 3b as bridging thereover.
As an example, one strip of the pressure bearing member 18 is arranged so as to transverse all of the shaped-steel joint portions 3b which are arranged in parallel in the bridge width direction. As another example, it is possible that the pressure bearing members 18 are formed to have divided length and each divided pressure bearing member 18 can be arranged on the flanges 10 of two or more adjacent shaped-steel joint portions 3b as bridging thereover.
In the case that the pressure bearing member 18 is utilized, a part of a group of the connection strip members 13 is inserted through a portion of the pressure bearing member 18 supported on the flange 10 while being inserted to the through hole 8b of the flange 10 of the shaped-steel joint portion 3b. Then, the nut 17 is screwed and fixed on the upper face of the pressure bearing member 18.
Further, another part of the group of the connection strip members 13 arises through a space between the adjacent shaped-steel joints 3, that is, arises through a space between the flanges 10. The upper end of the connection strip member 13 is inserted to a portion 18a of the pressure bearing member 18 existing as being extended between the shaped-steel joint portions 3b, that is, the pressure bearing member portion 18a existing as being extended between the flanges 10. Then, the nut 17 is screwed, thereby being fixed on the upper face of the pressure bearing member portion 18a.
A shaped-channel such as a C-shaped channel and an L-shaped channel can be utilized for the pressure bearing member 18. The shaped-channel such as a C-shaped channel and an L-shaped channel is suitable for the pressure bearing member 18 as having large bending strength and a large connection effect with the connection concrete 14. The present invention is not intended to exclude a case that a steel flat strip plate is utilized for the pressure bearing member 18 instead of the shaped-channel.
Next, the lateral connecting strip member 7 formed of a steel bar, a steel cable, a cable made of another high-tension fibers and the like is inserted to the through hole 8a of each shaped-steel joint portion 3b supported on the bridge abutment face 12. The shaped-steel joint portions 3b of the concrete girders adjacent in the bridge width direction are mutually connected via the lateral connecting strip member 7. The concrete girders 2 adjacent in the bridge width direction are mutually connected via the connection.
As described above, the lateral connecting strip member 7 is inserted through all of the shaped-steel joint portions 3b arranged in parallel in the bridge width direction. Then, each end of the strip member 7 is fixed to the outer side faces of the web 6 as screwing the nuts 19 at the outer side faces of the web 6 of the shaped-steel joint portion 3b placed at the outermost end in the bridge width direction.
Before the operation of screwing the nut 17 to the connection strip member 13, the operation of inserting the lateral strip member 7 and screwing the nut 19 can be performed. Alternatively, the operation of inserting the lateral strip member 7 and screwing the nut 19 can be performed after the operation of screwing the nut 17 to the connection strip member 13.
Further, filling concrete 20 is filled along the bridge length direction in the space between the concrete girders 2 of the joint-equipped PC concrete girder 1. Each end of the filling concrete 20 is connected to the connection concrete 14 while being connected to each concrete girder 2, so that a concrete floor slab is formed with the concrete girder 2 and the filling concrete 20.
A roadbed is formed by providing concrete pavement or asphalt pavement 21 on the upper face of the concrete floor slab. Accordingly, the pavement 21 is integrally laminated so as to cover the concrete girder 2, the filling concrete 20 and the shaped-steel joint 3.
The filling concrete 20 may be filled before or after the process of screwing the nut 17 to the connection strip member 13, or before or after the process of inserting the lateral connecting strip member 7.
The shaped-steel joint portion 3b of the joint-equipped PC concrete girder 1 is directly supported by the bridge abutment face 12 of the concrete bridge pier 4. Alternatively, a ground member 22 made of concrete or shaped-steel is arranged on the bridge abutment face 12 and the shaped-steel joint portion 3b is supported on the ground member 22, that is, the shaped-steel joint portion 3b is indirectly supported on the bridge abutment face 12 via the ground member 22 while the ground member 22 is buried in the connection concrete 14.
The connection concrete 14 includes a bottom concrete 14a filled in a space formed by the ground member 22 and a side concrete 14b covering the side face of the shaped-steel joint 3. Accordingly, the shaped-steel joint portion 3b, the lateral connecting strip member 7, the connection strip member 13, the nuts 17, 19, the pressure bearing member 18 and the ground member 22 are buried in the connection concrete 14.
With the joint-equipped PC concrete girder 1, the shaped-steel joint portion 3b is supported on the bridge abutment face 12 of the bridge pier 4. Alternatively, as illustrated in
The respective shaped-steel joint portions 3b protruded from the end face of the concrete girder 2 and each end of the concrete girder 2 are received on the bridge abutment face 12 of the bridge pier 4, and then, connection with the connection strip member 13, insertion of the lateral connection strip member 7 and casting of connection concrete 14 on site are performed.
As a matter of course, the example illustrated in
In the case of the multi span rigid-frame bridge in
Number | Date | Country | Kind |
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2008-274493 | Oct 2008 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2009/005505 | 10/21/2009 | WO | 00 | 4/6/2011 |
Publishing Document | Publishing Date | Country | Kind |
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WO2010/047096 | 4/29/2010 | WO | A |
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