JP2004044236A - Wooden bridge employing outer cable-based prestressed laminated lumber bridge girder, wooden bridge overhanging erection method based on outer cable system, and wooden bridge girder constructed according to the overhanging erection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a laminated lumber bridge girder which is enhanced in resistance to deflection, and to construct a long-span wooden bridge by employing the laminated lumber bridge girder. <P>SOLUTION: In the wooden bridge which employs long beams made of laminated lumber as the main girder, prestress is applied to the laminated lumber main girder according to an outer cable system, by attaching angle-type anchorage fixtures and wooden anchorage blocks to the main laminated lumber girder. To implement an overhanging erection method, the laminated lumber long beams to which prestress has been applied according to an inner cable system are piled up on bridge piers while the number of the beams to be connected is progressively increased. Further, whenever a new upper stage is piled up, outer cables are attached to the connected beams which are set in the new upper stage, to thereby apply prestress to the connected beams, and at the same time the long beams in the upper- and lower-stages are fixed to each other by a plurality of deviation inhibiting fixtures. In this manner the bridge girder is overhangingly erected. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an outer cable anchoring portion for introducing a prestress by an outer cable system in a bridge girder of a wooden bridge made of laminated wood, and a wooden bridge while introducing a prestress by an outer cable system. The present invention relates to an overhang erection method for constructing a bridge girder and a bridge girder of a wooden bridge by the overhang erection method.
[0002]
2. Description of the Related Art Generally, bridges cross roads, valleys, lakes, straits, or other roads, railways, waterways, etc., which are obstacles to transportation, on roads, railroads, waterways, etc. Concrete bridges that are mainly constructed of reinforced concrete, prestressed concrete, steel reinforced concrete, unreinforced concrete, etc. They are classified into (2) steel bridges mainly made of steel, (3) masonry bridges mainly made of stone and brick, and (4) wooden bridges mainly made of wood.
In recent years, steel and prestressed concrete are mainly used, such as composite girder integrating steel main girder and reinforced concrete floor slab, and girder integrating H-shaped steel in concrete for integration of strength and durability. Have been.
Recently, however, a wood bridge made mainly of wood has been attracting attention, in conjunction with increasing social awareness of the global environment and the natural environment.
In addition, wooden bridges have been attracting attention because of the recent improvements in the manufacturing and processing techniques of glued laminated timber, antiseptic techniques, and various joining techniques. Is easily supplied.
However, bridges are required to have the strength and durability required to satisfy their intended use, suitability for the environment, and ease of maintenance and management.Therefore, wooden bridges with the required strength and durability, especially It was very difficult to build a long span wooden bridge.
[0003]
As described in the above-mentioned prior art, recently, with the increase in social awareness of the global environment and the natural environment, wooden bridges have been reviewed mainly by local governments, and the load on the road surface has increased. There is also a growing demand for a sustainable wooden bridge or a longer span wooden bridge. However, if the road surface load becomes large or the span becomes long, resistance to the deflection of the main girder due to the road surface load becomes a problem. In addition, the length of the glued laminated lumber used for the main girder is limited to some extent from manufacturing and transportation. Therefore, in order to obtain the required length of the main girder made of glulam, it is necessary to firmly join a plurality of glulam timber beams.
As one of the solutions to this problem, it is conceivable to increase the resistance to bending by introducing prestress into the main girder made of laminated wood used for wooden bridges in accordance with a prestressed concrete (PC) girder. In addition, the present applicant has previously devised a method of strengthening the bonding of the glued laminated lumber by the inner cable method (refer to Japanese Patent Application Laid-Open No. 2000-226811 "Kibashi using prestressed wooden deck"). However, in the inner cable system, the number of inner cables increases with the length of the wooden bridge, which not only requires a large-capacity PC steel material, but also complicates construction. In addition, it is not easy to join a plurality of laminated materials to which the prestress has been introduced by the inner cable, and there is also a difficulty in maintenance.
The problem to be solved by the present invention is to solve the problem of the introduction of prestress by the inner cable system by introducing the prestress by the outer cable system, and to construct a glued-girder bridge girder having improved resistance to bending, or The purpose of the present invention is to realize a longer span bridge by stacking and gluing laminated timbers on a pier.
[0004]
As a result of intensive studies, the present inventor has solved the above-mentioned problem to be solved by the following means.
(1) In a wooden bridge formed by using a long beam made of laminated wood as a main girder of a bridge girder, an external cable is provided on the main girder made of laminated wood and prestress is introduced. A wooden bridge using prestressed glued-girder girder.
(2) The steel fixing plate and the identification attaching plate, in which the outer cable is attached or welded to a steel girder end reinforcing material wound around both ends of a laminated girder main girder, are the girder end reinforcing material. (1) an outer cable type prestressed laminated material according to the above (1), which is fixed to an angle type fixing bracket composed of a rib that reinforces a portion that protrudes from the prestressing force. A wooden bridge using bridge girders.
(3) The outer cable type prestressed assembly according to (1), wherein the outer cable is fixed to a wooden fixing block fixed to a side surface near both ends of the glued main girder. A wooden bridge using timber bridge girders.
[0005]
(4) The above-mentioned (1) to (3), wherein the laminated girder main girder is formed of a joining beam in which a plurality of laminated beam long beams are joined via a rectangular cylindrical joining aid. A wooden bridge using the external cable type prestressed glued laminated girder according to any one of the above.
(5) The laminated girder main girder is characterized in that a plurality of laminated beam long beams are joined via a rectangular cylindrical joining auxiliary tool having a partition wall in the center of the inside. A wooden bridge using the external cable type prestressed glued laminated girder according to any one of (3) to (3).
(6) The main girder made of laminated wood includes a PC steel material having a through hole formed in a length direction thereof, and a PC steel material inserted through the through hole, and fixing tools provided at both ends of the PC steel material. The outer cable type prestressed laminated timber bridge girder according to any one of (1) to (5), wherein an inner cable type in which prestress is introduced into the main girder is used in combination. A wooden bridge.
[0006]
(7) Laminated timber beams that have been prestressed by the internal cable method are stacked on the piers while increasing the number of joints sequentially, and the prestress is reduced by the internal cable method that is installed in the upper stage every time one stage is stacked. An outer cable is applied to the joint beam that joins the introduced long beams, prestressing is applied, and the upper and lower glued laminated timber beams are fixed with multiple slip stoppers, etc., and the bridge girder of the wooden bridge is extended and erected. A method of overhanging a bridge girder of a wooden bridge using an external cable method.
(8) Laminated timber beams with prestress introduced by the inner cable method are stacked on the piers while increasing the number of joints sequentially, and the prestress is reduced by the inner cable method installed at the upper stage every time one stage is stacked. An outer cable is arranged on the joint beam that joins the introduced long beams, and the upper and lower laminated wood long beams are fixed with a plurality of slip stoppers while applying prestress. Bridge girder of wooden bridge by overhanging construction method using external cable method.
[0007]
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view of a bridge girder made of prestressed glued laminated lumber, FIG. 2 is an external cable system using an angle type fixing bracket, and FIG. FIG. 4 is an enlarged view of the anchoring portion of the fixing block of the prestressed glued laminated timber, FIG. 4 is an enlarged view of the fixing block fixing portion, FIG. It is a figure which shows the construction procedure of the bridge girder made of an external cable system prestressed laminated wood by the construction method.
In the figure, 1 is a main girder made of laminated wood, 1a and 1b are long beams made of laminated wood, 2 is an inner cable (PC steel), 3 is an outer cable (PC steel), and 4 and 4 'are girder reinforcements (steel). 5) Angle fixing bracket, 6: Fixing tool, 7a, 7b: Support plate, 8: Floor slab, 9: Fixing block, 10: Fixing plate, 11: PC steel material for fastening, 12: Nut, 13 the bonding aid, 14 piers, 15 out studs, the _{P O} outer cable tension, _{P b} is a PC steel tension for consistency formation.
[0008]
As the method of introducing prestress in the length direction of the main girder made of glulam, the inner cable system and the outer cable system currently used for concrete girder bridges can be considered.
As shown in FIGS. 1 (a) and 1 (b), the inner cable system uses a PC steel material (hereinafter referred to as an inner cable) 2 in a through hole formed in the longitudinal direction of the main girder 1 made of laminated wood. The fixing tool 6 and the supporting plate 7a for transmitting the prestress from the inner cable 2 to the main girder 1 made of laminated wood are disposed at both ends of the main girder 1 made of laminated wood. In the case of a long span wooden bridge that cannot be accommodated by one glued laminated timber beam, a joining aid 13 to be described later is provided at a joint that joins the two glued laminated timbers. Further, in order to prevent the end portion of the main girder made of laminated wood from expanding due to the prestressing force applied to both ends of the main girder made of laminated wood, a steel girder reinforcing member 4 is provided on the outer periphery near the end of the main girder made of laminated wood. , 4 'are wound. In the drawing, reference numeral 8 denotes a floor slab.
[0009]
On the other hand, as shown in FIGS. 1 (a) and 1 (c), the outer cable system is a PC steel material (hereinafter referred to as an outer cable) 3 arranged along both side surfaces of a main girder 1 made of laminated wood. And a steel angle-type fixing bracket 5 (see FIG. 2) disposed at an end of the glued wood main girder 1 or a wooden fixed to a side surface near an end of the glued wood main girder 1. The fixing block 9 and the fixing tool 6 for fixing the outer cable 3 to the angle type fixing bracket 5 or the fixing block 9, the supporting plate 7 a, the fixing plate 10, and the like.
In the case of a long span wooden bridge that cannot be handled by a single glulam timber beam, a joining aid 13 is provided at a joint for joining two glulams, and a prestressing force applied to both ends of the glulam main girder is provided. In order to prevent the main girder end of the laminated wood from expanding, the girder end reinforcements 4 and 4 'are wound around the outer periphery near the end of the main girder made of laminated wood in the case of the inner cable system. Is the same as
The embodiment shown in FIG. 1D shows a case where the above-mentioned inner cable system and outer cable system are used together.
[0010]
Here, the glued laminated wood is a laminated board or small square wood or the like which is adhered in the length, width and thickness directions in parallel with each other in the fiber direction. It is a material that can be expected to have a strength equal to or higher than one material. In the present invention, the main girder 1 uses the long beam made of the laminated wood, and the prestress is applied to the main girder 1 to meet the intended use of the wooden bridge. It realizes a wooden bridge structure with character.
[0011]
Next, the fixing structure of the outer cable 3 will be described. As the fixing structure of the outer cable, an angle type shown in FIG. 2 and a fixing block type shown in FIG. 3 can be considered. 2 and 3 show an embodiment in which an inner cable and an outer cable are used together.
(Angle method)
In the angle method, as shown in FIG. 2, the fixing steel plate 5a having a width larger than the width of the square tubular girder end reinforcing material 4 wound around the outer periphery of the vicinity of the end of the glued main girder 1; An angle constituted by a plurality of reinforcing ribs 5c welded to a portion 5b projecting right and left from the girder end reinforcing member 4 when the fixing steel plate 5a is joined to one opening of the girder end reinforcing member 4. The external cable 3 is fixed by using a system fixing metal fitting 5 (see FIG. 5).
This angle fixing metal fitting 5 is used by being attached to both ends of a main girder 1 made of glued wood on which the girder end reinforcing material 4 is wound, so that a plurality of reinforcing ribs 5 c are formed on the girder end reinforcing material 4. The outer cable 3 is inserted into a through hole formed in the overhanging portion 5b of the fixing steel plate 5a in close contact with the side surface, and the overhanging portion 5b of the fixing steel plate 5a is deformed by the introduction of tension to the outer cable 3. The rib 5c and the side surface of the girder end reinforcing member 4 correspond to the force to be made to allow the prestress to be introduced into the main glue 1 of the laminated wood.
When the girder end reinforcing member 4 is made of steel, the angle type fixing bracket 5 and the girder end reinforcing member 4 are integrated by welding (see FIG. 2D), and the main body made of laminated wood is used. If it is used by attaching it to both ends of the beam 1, a more robust fixing plate is obtained, which is effective.
Further, when both the inner cable system and the outer cable system are used, a through hole for the inner cable may be formed in a portion of the angle system fixing plate 5 which is in contact with the end surface of the main girder 1 made of laminated wood. Only the PC steel material (inner cable) 2 and the PC steel material (outer cable) 3 can be fixed.
In the drawing, reference numeral 2 denotes an inner cable, 6 denotes a fixing device, 7a denotes a supporting plate, and 8 denotes a floor slab.
[0012]
(Fixing block method)
In the fixing block method, as shown in FIG. 3, a wooden fixing block is fixed to the side surface near the terminal of the main glue 1 made of laminated wood, and friction of the main girder 1 made of laminated wood and the fixing block 9 causes the outer cable 3 to be fixed. The tension is transmitted to the main beam 1 made of laminated wood as prestress.
In the case where the main girder is a joint girder formed by joining a number of glued laminated lumber beams, the fixing block 9 is disposed and fixed to an arbitrary side surface of the main girder 1 as necessary. The joining girder is divided at a certain interval, and an outer cable 3 is separately arranged between the fixing block fixed near the terminal and the fixing block disposed at an arbitrary position of the main laminated girder 1. It is also possible to introduce prestress throughout the bridge girder.
The wooden fixing block 9 is fixed to the glued main girder 1 by fixing the fixing block 9 and the glued main girder to through holes formed in the side surfaces of the fixing block 9 and the glued main girder 1. 1 is fastened by nuts 12 through supporting plates 7b provided at both ends of the PC steel material 11 for fixing.
[0013]
FIG. 4 is an enlarged view of a fixing portion between the wooden fixing block 9 and the main girder 1 made of laminated wood. _{P 0} In figure tension of the outer cable 3 (kN), _{P b} denotes tension stiffness consolidating PC steel member 11 (kN). Here tension P _b firmness consolidating PC steel member 11, the friction coefficient of the wooden fixing block 9 and the laminated wood made main beam 1 and mu, is obtained by the following expression.
P _b = P ₀ / μ
When now the friction coefficient μ of 0.5, tension P _b firmness consolidating PC steel member 11 from the above equation, it is necessary approximately twice the tension of the outer cable 3. For this reason, there is a possibility that the wooden fixing block 9 and the main girder 1 made of laminated wood may be deformed due to the tension of the PC steel material 11 for fastening. In order to prevent this, utilizing the fact that the physical compressive strength of wood is large in the fiber direction, as shown in FIG. It must be placed vertically.
The prestressing force of the outer cable 3 is introduced using a fixing structure via a wooden fixing plate invented by the present applicant (see Japanese Patent Application Laid-Open No. 2000-226811 "Kibashi using a prestressed wooden deck").
[0014]
FIG. 5 (a) shows that the laminated beams with prestress introduced by the inner cable method are sequentially stacked on the pier 14 in the length direction while increasing the number of joints by the outer cable method. FIG. 5B shows a side view of an embodiment of a bridge girder by an overhanging erection method in which prestress is introduced by a pair of outer cables 3, and FIG. 5B shows a top view of the bridge girder.
As shown in FIG. 5 (b), in this embodiment, the joining main girder 1 which is formed by joining a plurality of glued laminated long beams installed on the uppermost stage of the bridge girder is disposed at both ends of the main girder. The angle type fixing bracket 5 and two pairs of fixing blocks 9 disposed in the middle of the main girder are divided into three sections, and a pair of external cables are disposed in each section to apply prestress. This effectively introduces prestress to the entire long bridge girder. This makes it possible to build a wooden bridge with a central span of 100 m.
[0015]
The construction procedure of the external cable type prestressed glued laminated girder by the overhang construction method shown in FIG. 5 will be described with reference to FIG.
(A) First, a glued laminated lumber beam 1a into which prestress has been introduced by the inner cable 2 is installed and fixed on the pier 14.
(B) The laminated beams 1b and 1c having the same shape are joined and stacked on the laminated beam 1a with the joining aid 13 (see FIG. 1).
(C) An angle fixing metal fitting is attached to both ends of the connecting beams of the laminated beams 1b and 1c, and the outer cable 3 is disposed between the fixing beams and tensioned.
(D) The laminated beams 1a and 1b, 1a and 1c are respectively attached to the connecting beams of the laminated beams 1b and 1c using pre-stresses by the tension of the external cable by using the slip stoppers 15. Stick.
(E) Glued-lambda long beams 1d, 1e, 1f having the same shape as the glued-lambda long beam 1a are joined to the joining beams of the glued-lambda long beams 1b, 1c, by means of a joining aid 13 (see FIG. 1). In the same manner as described in (c), an angle type fixing bracket is attached to both ends of the glued laminated beams 1d, 1e, and 1f, and an outer cable is disposed therebetween. Then, while introducing the prestress, the connecting beams 1b and 1c and the connecting beams 1d, 1e and 1f are fixed by the stoppers in the same manner as described in (d) above.
(F) Thereafter, this operation is repeated as many times as necessary to complete the overhang by the laminated timber long beams.
(G) The overhanging portions of the glued laminated beam are closed by arranging the glued laminated main girder 1 by the same length as the bridge length, and fixing the fixing block to the side surface of the main girder 1. While laying the cables and tensioning them, an overhanging construction method using an external cable type prestressed laminated girder bridge girder by fixing the glued lumber main girder 1 and the glued lumber connecting beam located immediately below it with a slip stopper 15 is provided. To complete the bridge girder.
[0016]
According to the present invention, the following effects can be realized.
{Circle around (1)} Since the span of a wooden bridge, which was about 25 m in the past, can be expanded to about 100 m, a wooden bridge with few piers can be constructed even in a river having a wide river width, and the chance of the wooden bridge being washed away due to flooding can be reduced.
(2) Since the PC steel material that introduces prestress is arranged along the side of the bridge girder, maintenance and repair are easy.
(3) Expansion of the erection method (overhang erection method) becomes possible.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a prestressed glulam timber girder.
FIG. 2 is a structural diagram of an embodiment of a fixing part of a bridge girder made of an external cable type prestressed laminated wood using an angle type fixing metal.
FIG. 3 is a structural diagram of an embodiment of a fixing part of a bridge girder made of an external cable type prestressed laminated wood using a fixing block.
FIG. 4 is an enlarged view of a fixing block fixing portion.
FIG. 5 is a structural view of an embodiment of an external cable type prestressed laminated timber bridge girder by an overhanging erection method.
FIG. 6 is an explanatory view of a construction procedure of an external cable type prestressed glued laminated girder by an overhanging erection method.
[Explanation of symbols]
1: Bridge girder made of laminated wood 1a to 1f: Long beam made of laminated wood 2: Inner cable PC steel 3: Outer cable PC steel 4: Girder end reinforcement 5: Angle type fixing bracket 5a: Fixing steel plate 5b: Overhang of fixing plate Part 5c: rib of fixing plate 6: fixing device 7a, 7b: support plate 8: floor slab 9: fixing block 10: fixing plate 11: PC steel material for fastening 12: nut 13: joining aid 14: bridge pier 15: misalignment Clasp P _o : Tension of outer cable P _b : Tension of PC steel for fastening

Claims (8)

An outer cable type prestressed assembly, wherein an outer cable is arranged on the main girder made of the glued lumber and prestress is introduced in a wooden bridge using long beams made of glued lumber as a main girder of the bridge girder. A wooden bridge that uses timber bridge girders. The outer cable is a steel fixing plate and an identification attaching plate adhered or welded to a steel girder end reinforcement material wound around both ends of a laminated girder main girder protruding from the girder end reinforcement material. 2. A bridge girder made of an outer cable type prestressed glued laminated lumber according to claim 1, wherein the bridge girder is fixed to an angle type fixing bracket comprising a rib for reinforcing a portion to withstand a prestressing force. A wooden bridge. The outer cable type prestressed laminated timber bridge girder according to claim 1, wherein the outer cable is fixed to a wooden anchoring block fixed to a side surface near both ends of the glued main girder. A wooden bridge that has been adopted. The said main body girder made of laminated wood consists of the joining beam which several long beams made of laminated wood were joined through the joining aid of a square-tube shape, The laminated girder main girder of any one of Claims 1-3 characterized by the above-mentioned. A wooden bridge that adopts the pre-stressed glued laminated girder girder described above. The main body girder made of laminated wood, wherein a plurality of long beams made of laminated wood are joined via a rectangular cylindrical joining aid having a partition wall at the center of the inside. A wooden bridge using the external cable type prestressed glued laminated girder according to item 1. The main girder made of laminated wood is provided with a through-hole in the longitudinal direction thereof, and a PC steel material penetrated through the through-hole, and fixing devices provided at both ends of the PC steel material, and the main girder is provided with the main girder. 6. A wooden bridge using an external cable type prestressed laminated timber girder according to any one of claims 1 to 5, wherein an internal cable type in which prestress is introduced into the girder is used together. Prestress was introduced by the inner cable method in which prelaminated long beams with prestress introduced by the inner cable method were sequentially stacked on the piers while increasing the number of joints. An outer cable is placed on the joint beam that joins the long beams, prestressing is applied, and the upper and lower glued laminated timber beams are fixed with multiple stoppers etc., and the bridge girder of the wooden bridge is extended and installed. A method of overhanging the bridge girder of a wooden bridge using an external cable method. Prestress was introduced by the inner cable method in which prelaminated long beams with prestress introduced by the inner cable method were sequentially stacked on the piers while increasing the number of joints. An outer cable, comprising an outer cable arranged on a joint beam joined with a long beam and applying prestress while fixing the upper and lower laminated beam beams with a plurality of slip stoppers or the like. Bridge girder of wooden bridge by overhanging erection method.

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