JPH0868009A - Diagonal member for pc cable stayed bridge - Google Patents

Abstract

PURPOSE: To save labor in execution of work for constructing diagonal members for PC cable stayed bridge in prestressed concrete structure. CONSTITUTION: A diagonal member is composed of a closed section member 2, a PC cable 4 surrounded with a sheath 3 and inserted into the inside of the closed section member and in the length longer than the closed section member 2, and concrete 5 put in the inside of the closed section member 2. Prestress is introduced to the concrete 5 with stress applied to the PC cable 4 after hardening of the concrete 5, and the diagonal member 1 for PC cable stayed bridge is anchored to a main tower and a main girder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prestressed concrete diagonal member for a PC cable-stayed bridge.

[0002]

2. Description of the Related Art When prestressing concrete is used for the diagonal members in order to reduce the flexure of the main girders of PC cable-stayed bridges, construction is carried out by assembling support and formwork on the main girders. After placing the reinforcing bars and the PC cable, concrete is placed, after hardening the concrete, demolding,
After the tension of the PC cable, both ends of the PC cable are fixed to the main tower and main girder, but the prestressed concrete structure is adopted for the diagonal member because it requires labor for supporting and assembling and dismantling the formwork. It is an obstacle to the above.

The present invention was made by paying attention to the time and effort required to construct a prestressed concrete diagonal construction material, and proposes a diagonal construction material that simplifies construction.

[0004]

According to the present invention, a closed cross-section member is used as a concrete formwork, and a diagonal member is unitized in a state where a PC cable surrounded by a sheath is arranged inside the closed cross-section member. This eliminates the need for mold assembly and demolding, and simplifies construction.

The diagonal unit is composed of a closed cross-section material containing a PC cable and concrete filled in the closed cross-section material. The PC cable is tensioned after hardening of the concrete to introduce prestress to the concrete, Is fixed on the main girder.

Construction is carried out by installing a unit of diagonal material before concrete filling between the main tower and the main girder, filling concrete in the closed cross-section material, and tensioning the PC cable to fix both ends, or in advance. When the concrete is filled, the unit of diagonal members is installed, and then the tension and fixing of the PC cable ends.

Since the closed cross-section material becomes a concrete formwork, the assembling and disassembling of the formwork on the main girder is eliminated, and the flexure of the closed cross-section material at the time of placing concrete or before the PC cable is tensioned. In some cases, it is possible to deal with this by partially providing support, and the support work is simplified, resulting in labor saving in construction.

The closed cross-section material also has a role of bearing the tensile force due to its own weight after the diagonal member is erected between the main tower and the main girder, and by being used as a structural material, the labor of reinforcing bar reinforcement is saved. Contribute to labor saving in construction.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A diagonal member 1 according to the present invention has a closed cross-section member 2 as shown in FIG. 2, the PC cable 4 is tensioned after the concrete 5 is hardened as shown in FIG. 2, and is installed between the main tower 7 and the main girder 8 while prestressing the concrete 5. It is something.

The PC cable 4 is arranged in the closed cross-section member 2 in a suspended line shape while being inserted into the sheath 3, and is fixed to the closed cross-section member 2 in the arranged state. As the closed cross-section member 2, in addition to steel pipes and rectangular steel pipes, pipes of reinforced fiber plastic having sufficient tensile strength to resist tensile force due to its own weight are used, but the cross-sectional shape is not limited to circular or rectangular. Absent. Moreover, in addition to steel materials such as PC steel twisted wire, the FRP is also used for the PC cable 5.
New materials such as reinforced fiber plastic and continuous fiber reinforcement are used.

As shown in FIG. 3, the closed cross-section member 2 is previously divided into two, for example, flanged components 20, 20 as shown in FIG. 3 for the convenience of arrangement of the sheath 3 through which the PC cable 4 is inserted. The closed cross-section material 2 is formed by welding or bolting. In that case, the joint between the components 20 and 20 is water-stopped if necessary. A spacer or a separator for arranging the sheath 3 in a predetermined curved shape is fixed inside the closed cross-section member 2, and the sheath 3 is fixed and held along the spacer or the like. The inner peripheral surface of the closed cross-section member 2 may also be provided with a dowel 21 or a rib for adhering to the concrete 5 to be filled later.

The closed cross-section member 2 serves as a formwork for concrete 5, and also has a role of bearing a tensile force due to its own weight after the diagonal member 1 is erected between the main tower 7 and the main girder 8.

The closed cross-section member 2 in which the PC cable 4 is incorporated together with the sheath 3 is installed between the main tower 7 and the main girder 8 by a crane installed on the main girder 8 or a wire hung on the main tower 7. After that, the closed cross-section member 2 is filled with concrete 5. If it is possible to install a crane with a high lifting capacity, concrete 5 can be filled before installing the diagonal member 1 between the main tower 7 and the main girder 8, and after the hardening, the diagonal member 1 will be installed to PC. The bending of the diagonal member 1 before the tension of the cable 4 is reduced. When the bending of the closed cross-section member 2 becomes a problem, the support is partially provided on the main girder 8.

As shown in FIGS. 4 and 5, both ends of the PC cable 4 have such a length that they project from the end surface of the closed cross section member 2 and are fixed in the main girder 8 and the main tower 7. Both ends are located on or near the surface of the main tower 7 and the main girder 8.

The erection section of the diagonal member 1 between the main tower 7 and the main girder 1 is 1
When the length of the diagonal member 1 exceeds the length, a plurality of diagonal members 1 are connected and installed. In that case, if the PC cable 4 is built in the closed cross-section member 2 as a unit, it is necessary to connect the closed cross-section members 2 and 2 and the PC cables 4 and 4.
If the cable 4 is given a length extending between the main tower 7 and the main girder 8 and continuously arranged in the required number of all diagonal members 1 between the main tower 7 and the main girder 8, the closed cross-section member 2 , 2 connection is enough.

A PC cable 4 is provided at both ends of the closed cross section member 2.
Since it is necessary to disperse and fix the end portions of the inside of the main tower 7 and the main girder 8 respectively, the cross-sectional area gradually increases from the closed cross-section member 2 side to the PC cable 4 end side, and The closed cross-section members 9, 9 having a continuous shape are joined, and the tapered closed cross-section members 9, 9 are embedded in the concrete 71, 81 of the main tower 7 and the main girder 8. The concrete 71 and 81 of the main tower 7 and the main girder 8 are placed so as to surround the closed cross-section material 9.

After the closed cross-section member 2 is installed, the closed cross-section member 9 is
Alternatively, if the erection work in the connected state is possible, it is joined to the closed cross-section member 2 before the erection. Main tower 7 for closed cross-section material 9
For securing the integrity of the main girder 8 and concrete
Although 91 and ribs are provided to project, the dowel 91 and the like may be provided on either the inner peripheral surface or the outer peripheral surface.

After the concrete 5 in the closed cross-section material 2, the concrete 81 of the main girder 8 and the concrete 71 of the main tower 7 are hardened, the end of the PC cable 4 on the main girder 8 side is made of concrete 81.
In the state of being fixed inside, tension is introduced to the PC cable 4 from the main tower 7 side to fix the end portion thereof, and the grout material 6 is filled in the sheath 3 to complete the erection work of the diagonal member 1.

FIG. 6 shows how the PC cable 4 is erected through the main tower 7. In this case, the two diagonal members 1 and 1 laid across the main tower 7 are connected by the PC cable 4. Therefore, it can be collectively lifted to a predetermined position of the main tower 7. In FIG. 6, the sheath 3 is omitted.

[0020]

As described above, the present invention is as described above. A closed cross-section member is used as a concrete formwork, and a diagonal member is unitized in a state in which a PC cable surrounded by a sheath is arranged inside the closed cross-section member. Since the assembly and disassembly of the formwork on the main girder are eliminated, the support can be supported by the partial installation of the support for flexing of the closed cross-section material during concrete pouring or before PC cable tension. The work is also simplified, and the work can be saved.

Further, since the closed cross-section material is used as a structural material that bears the tensile force due to its own weight after the diagonal member is erected between the main tower and the main girder, it is possible to eliminate the labor of reinforcing bar arrangement.

[Brief description of drawings]

FIG. 1 is a perspective view showing a diagonal member.

FIG. 2 is an elevational view showing a erected state of a diagonal member.

FIG. 3 is a cross-sectional view showing the inside of a diagonal member.

FIG. 4 is a cross-sectional view showing a joint portion between a diagonal member and a main girder.

FIG. 5 is a cross-sectional view showing a joint portion between a diagonal member and a main tower.

FIG. 6 is a sectional view showing an embodiment in which a PC cable is installed through a main tower.

[Explanation of symbols]

1 ... diagonal material, 2 ... closed cross-section material, 20 ... constituent material, 21 ...
Gibel, 3 ... Sheath, 4 ... PC cable, 5 ... Concrete, 6 ... Grout material, 7 ... Main tower, 71 ... Concrete, 8 ... Main girder, 81 ... Concrete, 9 ...
Closed cross-section material, 91 …… Givel.

Claims (1)

[Claims] 1. A prestressed concrete diagonal member erected between a main tower and a main girder of a PC cable-stayed bridge, which is surrounded by a closed cross-section material and a sheath which is inserted into the closed cross-section material and is longer than the closed cross-section material. The PC cable is composed of a PC cable and concrete filled in a closed cross-section material. The PC cable is tensioned after hardening of the concrete to introduce pre-stress to the concrete and is fixed to the main tower and main girder. Bridge diagonals.