JP2002138415A - Cross girder member for girder member in pc bridge and girder member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the generation of a cold joint at a time when the bridge-axial rectangular direction is given prestress for imparting rigidity and strength required for a cross girder in a girder member, on which a PC cable is anchored, in a PC bridge, and to improve the durability of the girder member and the appearance of a main girder. SOLUTION: A cross girder member 4 made of precast concrete previously prestressed is arranged at least one end of the cross girder 2d of the girder member 2, on which the PC cable 3 is anchored, and the cross girder member 4 is anchored onto concrete constituting a girder member 2 main body in the periphery of the member 4 in the case of the manufacture of the girder member 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PC bridge constructed by introducing prestress by a PC cable installed in the bridge axis direction of a main girder connecting precast concrete girder members in the bridge axis direction. The present invention relates to a cross beam member forming a cross beam of a beam member to which a cable is fixed, and a cross beam member using the cross beam member.

[0002]

2. Description of the Related Art FIG. 5 shows a PC bridge (prestressed concrete bridge) in which prestress is introduced in the bridge axis direction by a PC cable installed between fulcrums of a main girder. The main girder is composed of a plurality of precast girder members, such as a PC box girder bridge, and is disposed outside the cross section of the main girder, such as between upper and lower slabs.
When prestress is introduced while connecting the girder members with the C cable, the end of the PC cable is fixed to the girder member located on a fulcrum such as a pier or abutment.

The girder member is composed of upper and lower floor slabs and a web connecting the two slabs, and a PC cable is deflected between the upper and lower floor slabs of the girder member located on the fulcrum to fix the ends. The cross beam is formed. However, since it is necessary to provide the cross beam with sufficient strength and rigidity to bear the tension of the PC cable, conventionally, as shown in FIG. A prestress is introduced by arranging a PC steel material in a portion orthogonal to the bridge axis. If prestress is not introduced, the cross beam becomes thicker and the weight of the beam member becomes extremely large.

The girder member is made of precast concrete and then conveyed to the site. Since the girder member located on the fulcrum has a horizontal girder and is therefore heavier, at least the girder member is required in terms of conveyance efficiency. The cross beam portion is often formed of cast-in-place concrete, in which case the PC steel material is fixed to the peripheral surface of the cross beam after tensioning.

[0005] As shown in Fig. 11, the end portion of the PC steel is fixed to a box-shaped cavity previously formed around the cross beam when concrete is laid in the cross beam portion or the upper floor slab portion. It is necessary to fill concrete into the cavity after fixing on the coating, but in that case, the concrete poured in at the time of forming the cavity and the concrete to be filled later tend to become a cold joint, and the joint joint tends to become a water path Therefore, rainwater infiltration causes obstacles such as rusting on the fixing tool and the PC steel, peeling of concrete, and the like, resulting in a decrease in durability of the girder member.

[0006] Even when the entire girder member including the cross girder portion is precast at once, since the cross girder portion is formed by concrete cast at once, when the PC steel material is arranged, the pre-tension type is used. It is difficult to introduce prestress, and PC is required only after concrete is laid on cross beam
Since the fixing of the end portion of the steel material still cannot be performed, post-filling of the fixing portion with concrete is necessary, and there is a problem that the durability of the girder member is reduced by the cold joint.

Further, if concrete is filled to cover the fixing portion after the PC steel material is fixed, the joint of the concrete is exposed on the surface such as the side surface of the girder member, so that the appearance of the PC bridge is deteriorated.

In view of the above background, the present invention proposes a horizontal girder member which constitutes a girder member having high durability and aesthetic appearance by eliminating the occurrence of a cold joint, and a girder member using the same.

[0009]

According to the present invention, a precast pre-stressed precast concrete cross beam member is disposed at least at one end of a cross beam member to which a PC cable is fixed. By fixing the cross girder member to the concrete that constitutes the girder member body around it, the occurrence of cold joints due to the introduction of prestress to the cross girder is eliminated, rusting on fixing tools etc. by the cold joint, concrete Prevents peeling, etc.
Improves the durability of the girder members and the beauty of the PC bridge.

The cross beam member has an opening for inserting a PC cable as described in claim 1, is made of precast concrete, and has a bridge shaft for securing bending rigidity and bending strength against the tension of the PC cable. Prestress is applied at right angles.

The cross beam member is disposed at at least one end in the bridge axis direction of the cross beam member, and the periphery of the cross beam member is fixed to concrete constituting the main body of the cross beam member. To form One or a plurality of prestressed transverse girder members are arranged in the direction of the bridge axis of the transverse girder, depending on the number of PC cables fixed and the magnitude of tension on the PC cables.

When the girder member is located at the fulcrum at the end of the main girder, the PC cable installed up to the girder member only needs to be fixed, so that the horizontal girder member is disposed at at least one end of the horizontal girder. However, when located at the fulcrum of the middle part of the main girder, the PC cables installed on both sides of the girder member are fixed, so that the horizontal girder members are arranged at least at both ends of the horizontal girder.

The prestress is given by tensioning a tendon such as PC steel material arranged in a direction perpendicular to the bridge axis of the cross beam member. The tension member is arranged in any direction, such as a vertical direction or a horizontal direction, except for the opening. However, if the prestress is given by pretension as described in claim 2, the tension member is produced at the time of manufacturing the cross beam member. Since the end portion can be prevented from being exposed to the peripheral surface of the cross beam member, a shear connector for ensuring the integrity of the beam member main body with concrete is protruded on the peripheral surface of the cross beam member as described in claim 3. There is an advantage of eliminating interference with the shear connector when installing. In this case, in addition to partially projecting the shear connector in the circumferential direction, the shear connector can be continuously projecting, so that the degree of freedom in projecting increases.

The girder member is cast with concrete including the cross beam in a state where the cross beam member having the tendon end fixed to the periphery of the precast concrete is disposed at the end of the cross beam in the bridge axis direction. Therefore, the end of the tendon member is not exposed to the cross-girder peripheral surface regardless of the method of introducing the prestress into the cross-girder member. As a result, post-filling of concrete to cover the tendon ends is not required,
The occurrence of cold joints is eliminated, and the aesthetics of the PC bridge is also improved.

The cross beam member is disposed at at least one end of the cross beam of the girder member, so that the cross beam portion can be used as a disposal form when concrete is cast in the cross beam portion or the entire girder member including the cross beam portion. Therefore, the assembly and disassembly of the formwork at that portion becomes unnecessary, and labor saving at the time of manufacturing the girder member is achieved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 3, the cross beam member 4 of the first embodiment has an opening 7 through which a PC cable 3 is inserted.
It is made of precast concrete 5 in a state where a prestress is applied by a tension member 6 disposed inside, and becomes a part of the girder member 2 which is one block constituting the main girder 1.

The main girder 1 is constructed by connecting precast concrete girder members 2 in the direction of the bridge axis as shown in FIG. 5, and the girder members 2 located other than the fulcrum indicated by △ are the upper floor slab 2a and the lower floor slab. 2b and a web 2c connecting the two slabs 2a and 2b.

A horizontal girder 2d having a thickness sufficient to bear the tension of the PC cable 3 is provided between the upper floor slab 2a and the lower slab 2b of the girder member 2 on which the PC cable 3 is fixed. Is formed, and the cross beam member 4 becomes a part of the cross beam 2d.

The horizontal girder member 4 is formed in a plate shape or a block shape as shown in the figure according to the shape of the girder member 2.
The tension members 6 are arranged in the direction perpendicular to the bridge axis, such as in the plane of the cross beam member 4, and apply prestress to the precast concrete 5 in that direction. When an opening 2e penetrating in the bridge axis direction is formed in the cross beam 2d to reduce the weight of the beam member 2, an opening 4a is also formed in the cross beam member 4. The openings 2e and 4a are formed in portions other than the positions where the PC cable 3 and the tendon 6 are arranged.

FIGS. 1 to 3 show the case where the tendon 6 is disposed only in the horizontal direction inside the cross beam member 4. FIG.
The relationship between the cross beam member 4 and the beam member 2 in the case where is arranged is shown. The tension member 6 has the necessary rigidity and strength of the cross beam member 4 if the opening 7 and the opening 4a are removed. It is arranged in an arbitrary direction in the precast concrete 5 within a range enough to cause the precast concrete 5 to move.

Tensile members 6 are arranged in a sufficient number for reinforcement by the introduction of prestress, and prestress is introduced into precast concrete 5 by pretension or post tension. As the tension member 6, a linear material made of fiber reinforced plastic is used in addition to steel materials such as PC steel and bar steel.

When prestress is introduced by pretension, as shown in FIG. 1, FIG. 2 and FIG. The tendon 6 is embedded in the
Although there is an advantage that it can be prevented from being exposed on the surface of the cross beam, the cross beam member 4 is finally cast afterwards and is buried in the concrete constituting the cross beam 2d together with the cross beam member 4, so that the post tension is Therefore, even when the prestress is introduced, the end fixing portion of the tension member 6 is not exposed on any surface of the girder member 2, and the appearance of the PC bridge is not deteriorated.

PC installed between fulcrums as shown in FIG.
The cable 3 penetrates the cross beam 2d on the fulcrum, and is fixed to the cross beam member 4 located on the opposite side of the middle portion of the PC cable 3 with respect to the cross beam 2d. The end of the PC cable 3 is a cross beam member 4
And is fixed to the precast concrete 5.

In the drawing, since the girder member 2 located on the fulcrum at the middle part of the entire length of the main girder 1 is shown, the horizontal girder members 4, 4 are arranged at both ends of the horizontal girder 2d in the bridge axis direction. However, when the girder member 2 is located on a fulcrum at the end of the entire length of the main girder 1, the PC cable 3 is fixed to only one side with respect to the cross girder 2d. It suffices that it is arranged only at the end where the 2d PC cable 3 is fixed.

Referring to the girder member 2 located on the left fulcrum in FIG. 5, the PC cable 3 installed on the right side of the fulcrum penetrates through the opening 7 of the right girder member 4 on the right side of the cross girder 2d. Is fixed to the cross beam member 4 through the opening 7 of the cross beam member 4. The PC cable 3 is also provided on the left side of the left fulcrum in FIG.
Is installed, the end of the PC cable 3 passes through the opening 7 of the left cross member 4 and is fixed to the right cross member 4.

As shown in FIG. 1 to FIG.
The opening 7 for inserting the cable 3 is formed by embedding a tubular form 8 such as a steel pipe in the precast concrete 5, and a plate or the like having an opening on the fixing-side surface of the opening 7 where the PC cable 3 is fixed. Of the supporting plate 9 is embedded. FIG. 1 is a view taken along the line xx of FIG. 3, and FIG. 2 is a view taken along the line yy of FIG. 3. FIG. 1 shows one surface of the cross beam member 4, and FIG. Is shown. FIG. 4 shows how the horizontal girder members 4 are arranged.

As shown in FIG. 3, a sheath 10 connected to the opening 7 where the end of the PC cable 3 is fixed is embedded in the concrete of the cross beam 2d. Cross beam members 4 on both sides of cross beam 2d
In the case where 4 is arranged, it is arranged between the openings 7, 7 of both cross beam members 4, 4.

In the drawing, as shown in FIGS. 3 and 6- (b), the cross beam member 4 is disposed at the end of the cross beam 2d so as to be embedded in the upper deck 2a, the lower deck 2b, and the web 2c around its periphery. In addition, a plate for securing the integrity of the girder member 2 with concrete, or a perforated plate or a shear connector 11 such as a reinforcing bar shown in FIG. If the embedding depth of the cross beam member 4 in the concrete around is large, integrity of the beam member 2 with the concrete can be obtained at the embedding portion. Therefore, in order to ensure the integrity, the sheer connector 11 is necessarily protruded. No need.

The two-dot chain line on the inner peripheral side of the solid line showing the outer shape of the cross beam member 4 in FIG. 1 and the broken line on the inner peripheral side of the solid line showing the outer shape of the cross beam member 4 in FIG. Lower deck
2b shows the position of the inner peripheral surface of the web 2c, and shows that the periphery of the cross beam member 4 is embedded to that position.

When the shear connector 11 is protruded around the horizontal girder member 4, the shear connector 11 ensures the integrity of the girder member 2 with concrete. 2b, and need not be arranged to be embedded in the web 2c.

In each case, the cross beam member 4 is disposed at at least one end of the cross beam 2d in the bridge axis direction, so that the cross beam 2d bears the tension of the PC cable 3 and contacts the concrete forming the cross beam 2d. From that to the concrete.

In FIG. 5, since the cast-in-place concrete 15 is cast between the girder member 2 located on the fulcrum and the adjacent girder members 2 on both sides thereof, the main girder 1 is formed. 3
In the above, shear connectors 11, 11 composed of upper and lower rebars are provided so as to straddle between the cast-in-place concrete 15, 15.

The manufacturing procedure of the girder member 2 when the entire girder member 2 is made of precast concrete will be described with reference to FIGS. As shown in (a), formwork 12a, 12b, 12c is assembled below lower deck 2b, outside of web 2c, and below the portion of upper deck 2a projecting from web 2c, as shown in (b). Reinforcing bars 13 are arranged on the projecting portions of the lower slab 2b, the web 2c, and the upper slab 2a.

At the time of (b), as shown in (c), the cross beam member 4 is placed on the reinforcing bar 13 of the lower slab 2b while being floated from the formwork 12a. At this time, if a perforated plate shown in FIG. 7 is used as the shear connector 11, a reinforcing bar is passed through the hole of the plate as necessary. FIG. 9 shows a cross section taken along line AA of FIG.

Subsequently, as shown in (d), the web of the upper deck 2a
2c, 2c, the reinforcing bar 13 and the tendon 14 for placing the tendon 14 in the direction perpendicular to the bridge axis on the upper deck 2a, and the lower deck 2b
And the inside of the web 2c, and the webs 2c and 2c of the upper deck 2a
Formwork 12d, 12e, 12f is installed under the part between, (e)
As shown in the figure, between the molds 12a and 12d, between 12b and 12e, and
The girder member 2 is manufactured by placing concrete on c and 12f.

The overhang length of the upper floor slab 2a on both sides of the spar member 2 overhanging from the web 2c is not necessarily symmetrical as shown in FIG. Since the cross girder member 4 is used as a formwork on the bridge axis side (wife side) of the cross girder 2d, the upper formwork 12d of the lower floor slab 2b, the formwork 12e inside the web 2c, and the upper floor slab The lower formwork 12f of the portion of the web 2a between the webs 2c, 2c is arranged between the end of the beam member 2 and the cross beam member 4. Fig. 10 shows B-
2 shows a cross section taken along line B.

As shown in the figure, cross members 4 and 4 are arranged at both ends of the cross beam 2d, and the periphery of the cross beam member 4 is surrounded by an upper deck 2a and a lower deck 2a.
2b and upper deck 2a and lower deck when embedded in web 2c
If concrete is poured into 2b and web 2c part,
Since the girder member 4 is buried in the concrete of the girder member 2 and is fixed, the concrete of the part other than the girder members 4 and 4 of the girder 2d is cast as precast concrete at the factory, and after being transported to the site, the girder is Concrete can be cast between the members 4 and 4 to complete the cross beam 2d.

[0038]

According to the first aspect of the present invention, the cross beam member is disposed on at least one end of the cross beam of the beam member to which the PC cable is fixed, and is made of precast concrete in a state where a prestress is applied in a direction perpendicular to the bridge axis. Therefore, it is possible to avoid exposing the ends of the tendons due to the introduction of prestress when the entire cross beam is formed of concrete cast at once, eliminating the need for post-filling of concrete to cover the ends of the tendons become.

As a result, in producing the girder member of claim 4 using the horizontal girder member, the occurrence of cold joints is eliminated, rusting on the fixing tool, peeling of concrete, and the like are prevented. The durability of the bridge can be improved, and the aesthetic appearance of the PC bridge is also improved.

Since the cross girder member is disposed at at least one end of the cross girder of the girder member, the cross girder member can be used as a discarded formwork when concrete is laid on the cross girder. Thus, labor can be saved when manufacturing the girder member.

According to the second aspect of the present invention, since the prestress is applied by pretension, it is possible to avoid exposing the end of the tendon member at the time of manufacturing the cross beam member. In the case where a shear connector or the like for ensuring the integrity with the projection is provided, the degree of freedom in projecting can be increased.

According to the third aspect, since the shear connector is provided on the peripheral surface of the horizontal girder member, the integrity of the main body of the girder member with concrete is improved.

[Brief description of the drawings]

FIG. 1 is a view taken along line xx of FIG. 3 showing an example of manufacturing a cross beam member.

FIG. 2 is a view taken in the direction of the arrow yy in FIG. 3;

FIG. 3 is a longitudinal sectional view parallel to the bridge axis direction, showing a production example of the cross beam member.

FIG. 4 is an elevational view showing the arrangement of reinforcing bars inside the cross beam member.

FIG. 5 is an elevation view showing an example of erection of a main girder.

FIG. 6A is a longitudinal sectional view showing another example of manufacturing the cross beam member, and FIG. 6B is a sectional view taken along line XX of FIG.

FIG. 7 is an elevational view showing another example of projecting a shear connector.

FIGS. 8A to 8E are elevation views showing a procedure for manufacturing a girder member.

FIG. 9 is a sectional view taken along line AA of FIG. 8- (c).

FIG. 10 is a sectional view taken along line BB of FIG. 8- (e).

11A is an elevation view showing an example of introduction of prestress into a conventional girder member, and FIG. 11B is a cross-sectional view taken along line CC of FIG. 11A.

[Explanation of symbols]

1 ... main girder, 2 ... girder member, 2a ... upper floor slab, 2b ... lower floor slab, 2c ... web, 2d ... horizontal girder, 2e ... opening, 3 ...
PC cable, 4 ... horizontal beam member, 4a ... opening, 5 ...
Precast concrete, 6 ... tendon, 7 ... opening, 8 ... formwork, 9 ... supporting plate, 10 ... sheath, 11 ...
Shear connectors, 12a, 12b, 12c, 12d, 12e, 12f ...
... Form, 13 ... Rebar, 14 ... Tensioner, 15 ... Concrete cast-in-place.

Claims (4)

[Claims] 1. A PC bridge constructed by introducing prestress into a main girder by a PC cable erected in a bridge axis direction of a main girder connecting a precast concrete girder member in a bridge axis direction. A girder member constituting a cross girder of a girder member to be fixed, having an opening for inserting a PC cable, and a girder for a PC bridge made of precast concrete in a state where prestress is applied in a direction perpendicular to the bridge axis. Cross beam member for members. 2. The girder member for a girder member in a PC bridge according to claim 1, wherein the prestress is given by pretension. 3. The girder member for a girder member of a PC bridge according to claim 1, wherein a shear connector fixed to the concrete constituting the main body of the girder member protrudes around the perimeter member. 4. A concrete structure wherein the cross beam member according to claim 1 is disposed at at least one end of the cross beam in the bridge axis direction, and the periphery of the cross beam member constitutes a main body of the beam member. Girder members for PC bridges that are manufactured by fixing them to the bridge.