RU2801995C1 - Method for reconstruction of prestressed reinforced concrete box-shaped structure - Google Patents

Abstract

FIELD: bridge engineering.

SUBSTANCE: methods and devices for the reconstruction of bridges. The method for reconstructing a prestressed reinforced concrete box span arch structure consists in preliminarily calculating the locations for drilling holes for installing high-strength bundles of strands. The calculation is made according to the design for each semi-arch separately. On the outer side of the extreme ground parts of the support of each semi-arch, a reinforced concrete array is installed for anchoring the strands and jacks are installed in this place. Elliptical holes are drilled in the calculated places of the box span of each semi-arch. After that, bundles of strands are pulled and fixed on the bottom plate. The calculated parts of the extreme supports of each semi-arch are dismantled. By means of jacking, each semi-arch is rotated relative to the channel supports with simultaneous lowering of the extreme ground parts of the semi-arches until the required span line is restored. Next, the central lock is fixed between the semi-arches and the extreme supports are equipped to fully support the span structure on them.

EFFECT: improvement of the bridge construction.

2 cl, 4 dwg

Description

The present invention relates to the field of bridge building, namely to methods and devices for the reconstruction of bridges.

The span structures of arch bridges are always lighter and more economical than beam bridges. However, the transfer of thrust to the supports requires a significant increase in their size, especially the extreme supports (abutments). Therefore, arched bridges are usually expedient with good soils and a relatively low height of the supports. Reinforced concrete arches or vaults cover spans from 60-80 m or more; modern arch bridges have spans up to 300 m.

In reinforced concrete bridges of the arch system, vaults or arches serve as the main bearing elements.

The vault/arch is a curved slab, the width of which is much greater than its thickness. An arch is a curved beam, the transverse dimension of which is usually less than its height. Since arches/vaults are mainly in compression, it is most efficient to use high-grade concrete in them.

With long-term use of arched span structures, temperature fluctuations, deformation of supports, shrinkage and creep of concrete may cause subsidence and displacement of the central lock.

In the case of the aforementioned deformations, the carriageway line of the span structure sags, which leads to the impossibility of the full use of the bridge structure, and sometimes to the emergency collapse of its parts.

To restore such deformations of the bridge structure, various methods are used, for example, with the replacement of the span, or by raising the semi-arches by installing temporary supports and pulling the guys, or by installing additional supports, and so on.

However, such methods have disadvantages associated with the installation of additional structures and the use of expensive equipment.

Disclosure of invention

The objective of the invention is to create a method for the reconstruction of a prestressed reinforced concrete box span, which ensures the suspension of the deformation of the reinforced concrete box structure of the arch span, caused by concrete creep and stress relaxation, and as a result of complete restoration of the required span line.

The technical result of the claimed invention is:

- Reduction of reconstruction time;

- Minimizing the use of additional equipment;

- Refusal to erect temporary and permanent additional structures;

- Minimization of labor costs.

The technical result is achieved due to the fact that the method of reconstructing a prestressed reinforced concrete box span consists in pre-calculating the places for drilling holes for installing high-strength bundles of strands, and the calculation is carried out according to the project for each semi-arch separately. Then, on the outer side of the extreme ground parts of the support of each semi-arch, a reinforced concrete array is installed for anchoring the strands and jacks are installed in this place. Next, elliptical holes are drilled in the calculated locations of the box span of each semi-arch, while the number of holes is calculated in accordance with the degree of deformation/lowering of each semi-arch. After that, bundles of strands are pulled and fixed on the bottom plate. Next, the calculated parts of the extreme supports of each semi-arch are dismantled. Then, by means of jacking, each semi-arch is rotated relative to the channel supports with simultaneous lowering of the extreme ground parts of the semi-arches until the required span line is restored. Next, the central lock is fixed between the semi-arches and the extreme supports are equipped to fully support the span structure on them.

The essence of the invention is illustrated by drawings.

Fig. 1. - View of the deformed arch span.

Fig. 2. - View of the arched span with installed equipment for reconstruction.

Fig. 3. - View of the arched span with lowered and rotated semi-arches.

Fig. 4. - View of the arched span after reconstruction.

The method for reconstructing a prestressed reinforced concrete box-shaped span 1 consists in pre-calculating the places for drilling holes 2 for the installation of high-strength bundles of strands 3, and the calculation is carried out according to the project for each semi-arch 4 separately. Then, on the outer side of the extreme ground parts of the support 5 of each semi-arch 4, a reinforced concrete array 6 is installed for anchoring the strands 3, and jacks 7 are installed in this place.

Next, elliptical holes 2 are drilled in the calculated locations of the box span 1 of each semi-arch 4, while the number of holes 2 is calculated in accordance with the degree of deformation / lowering of each semi-arch 4. The elliptical shape of the holes 2 in the top plate is caused by a special form of casting made of cast iron with an internal radius R = 54 cm, for smooth refraction of 19 high-strength strand bundles of 3 K-7 strands. Holes 2 for installing bundles of strands 3 are drilled using core drilling, in which, due to the point action of crowns along their radius, accurate cutting and bringing to the surface of a solid core is ensured. The core drilling method allows you to work with any high-strength materials in the most inaccessible places.

After that, bundles of strands 3 are pulled and fixed on the bottom plate 8.

Next, the settlement parts 10 of the extreme supports 9 of each semi-arch 4 are dismantled. To accomplish this task, the calculated overhead reinforced concrete parts 10 of the extreme supports 9 of each semi-arch 4 are cut off from the extreme (coastal) supports 9 with wedge-shaped jacks 7.

Then, by jacking, each semi-arch 4 is rotated relative to the channel supports 11 with simultaneous lowering of the extreme ground parts of the semi-arches 4 until the required line of the superstructure 12 is restored.

Next, the central lock 13 is fixed between the semi-arches 4 and the extreme supports 9 are equipped to fully support the superstructure 1 on them.

All of the above indicates the fulfillment of the task and the industrial applicability of the method for reconstructing a prestressed reinforced concrete box span.

List of positions:

1. prestressed reinforced concrete box span

2. holes

3. high-strength bundles of strands

4. semi-arch

5. extreme ground part of the semi-arch support

6. reinforced concrete array

7. jacks

8. bottom plate

9. extreme support

10. calculated part of the extreme supports

11. channel support

12. required superstructure line

13. central locking.

Claims (2)

1. A method for reconstructing a prestressed reinforced concrete box-shaped span arch structure formed by semi-arches, which consists in pre-calculating the places for drilling holes for the installation of high-strength bundles of strands, then on the outer side of the extreme ground parts of the support of each semi-arch, a reinforced concrete array is installed for anchoring the strands, and after that jacks are installed in this place, then elliptical holes are drilled in the calculated places of the upper slab of the box-shaped span of each semi-arch, into which bundles of strands are pulled and fixed on the lower slab of the span, parts of the extreme supports of each semi-arch are dismantled, then, by jacking, each semi-arch is rotated relative to the channel supports with simultaneous lowering of the extreme ground parts of the semi-arches until the required line of the superstructure is restored, fix the central lock between the semi-arches and equip the extreme supports for the full support of the superstructure on them. 2. The reconstruction method according to claim 1, characterized in that the places for drilling holes for the strands are calculated according to the project for each semi-arch separately.