CN106149538A - A kind of slab bridge - Google Patents

Abstract

The invention discloses a slab bridge, which is assembled from prefabricated low-height inverted T-shaped plates and belongs to the field of bridge engineering. The prefabricated inverted T-shaped plate includes a solid plate part in the middle of the cross section, flanges protruding from the bottom to both sides, and connecting ribs protruding outwards on the side of the plate and the upper surface of the flanges. After on-site assembly, concrete is poured on top of the T-shaped slab to form a slab bridge. The prefabricated inverted T-shaped plate of the bridge has a small hoisting weight and good integrity after the bridge is completed, and is suitable for bridges with a span of 16 meters or less. It is especially suitable for occasions that require rapid construction or cross-line construction. This type of bridge construction can reduce traffic interruption time, improve the connection reliability between prefabricated components, avoid common hinge cracking diseases of hollow slab bridges, and reduce life cycle costs.

Description

a bridge

technical field

The invention relates to a slab bridge, which belongs to the field of bridge engineering.

Background technique

In the small span range of less than 20 meters, the bridge type is mostly hollow slab bridge. The main reason is that the hollow slab bridge is constructed by the prefabricated assembly method. The prefabricated quality of the hollow slab is guaranteed, and the assembly construction speed is faster and more economical. However, with the increase of traffic flow on the road and the increase of overloaded vehicles, the hinge joints of the hollow slab bridge will be damaged. The general manifestation is that the bottom of the hinge joint cracks first, weakening the connection between the hollow slabs, and the concrete of the hinge joint is damaged. Rainwater infiltrates into the hinge joints from the bridge deck, which further aggravates the corrosion of steel bars and the deterioration of concrete, reduces the force transmission capacity of hinge joints, and weakens the cooperative bearing capacity of each slab. The part of the wheel load acting on the plate that is transmitted to the adjacent plate gradually decreases, and the load ratio of the plate on which the wheel is located gradually increases. This phenomenon is generally called "single plate force". Under the action of overloaded vehicles, the damage of the hinge joints is aggravated, and the hollow slab bears most of the wheel load. When it reaches a certain level, the hollow slab will break and cause the vehicle to fall into the bridge with the hollow slab.

The cast-in-place concrete slab can avoid the disease of the hollow slab bridge and has a long history of use, but the construction requires a lot of time and manpower, because formwork installation and removal, maintenance and other work are required. This construction method will greatly affect the traffic conditions because it needs to set up supports on the road. The long construction period has brought inconvenience to people, increased travel time and fuel consumption, and increased social costs. Therefore, there is an urgent need for a new type of slab bridge, which can strengthen the lateral integrity of the slab bridge and avoid "single-plate stress", while maintaining the advantages of easy construction of the hollow slab bridge.

Contents of the invention

The purpose of the present invention is to solve the deficiencies and problems existing in the above-mentioned prior art, and to provide a new type of slab bridge. After the inverted T-shaped slab (1) is assembled, the upper part of the slab and the joint cast-in-place concrete (7) are poured to form the stressed structure in the superstructure. The convex middle part of the cross-section of the inverted T-shaped plate (1) is solid, and the width is not less than half of the width of the prefabricated inverted T-shaped plate (1). The connecting rib (3) protruding from the lower part of the side of the board protrudes from the board where it is located, and the extension length is not less than half of the length of the flange (2), which can strengthen the connection between adjacent boards. The connecting ribs (4) protruding from the top of the slab can strengthen the bond between the cast-in-place concrete and the prefabricated inverted T-shaped slab (1), and enhance the overall mechanical performance. The connecting rib (5) protruding from the flange can delay or avoid cracking along the joint surface of old and new concrete here.

In order to further enhance the strength of the new-old concrete joint surface, the side of the upwardly protruding part of the inverted T-shaped plate (1) can be provided with a connecting rib (6) protruding from the upper part of the side of the plate. In order to ensure the reliability of the connecting rib, the end of the side connecting rib can be bent at 90 degrees.

In order to increase the span adapted to the slab bridge type, the inverted T-shaped slab (1) can be equipped with longitudinal prestressed tendons at the bottom, and prefabricated by pretensioning.

In order to further speed up the construction, the on-site reinforcement work can be reduced as much as possible, and the on-site installed reinforcement in the longitudinal joints between adjacent slabs can be made into a reinforcement cage, which can be directly placed in place after being transported to the site.

With the aging of bridges, there is an urgent need to quickly replace the previous small-span bridges. This type of bridge can meet the requirements of quick repair. Therefore, this bridge system can be used for new bridges or replacement of existing bridges, and the reasonable applicable span is 16 meters or less.

Compared with the prior art, a bridge of the present invention has the following beneficial effects:

1. This type of slab bridge improves the connection between prefabricated components and enhances the horizontal integrity of the bridge;

2. Lighter in weight, good in constructability, fast on-site construction at the bridge site, saving time and reducing traffic interruption;

3. Improve the safety of the construction area and reduce the impact on the environment;

4. Prefabricated components are used, and the concrete poured on site does not require formwork, which is convenient for quality control;

5. Avoid the hinge joint problem of the hollow slab bridge, reduce the maintenance cost during use, and reduce the life cycle cost.

Description of drawings

Fig. 1 is a cross-sectional schematic view of the entire bridge superstructure of the present invention.

Fig. 2 is a cross-sectional schematic diagram of an inverted T-shaped plate in the present invention.

Fig. 3 is a schematic diagram of the reinforcement of the plate girder of the present invention.

Fig. 4 is a schematic diagram of the reinforcement of the plate girder in the first embodiment.

Fig. 5 is a schematic cross-sectional view of the inverted T-shaped plate in the second embodiment.

Fig. 6 is a schematic diagram of the plate beam reinforcement in the second embodiment.

Fig. 7 is a schematic diagram of the plate beam reinforcement in the third embodiment.

Fig. 8 is a schematic diagram of No. 9 steel bar of the slab girder in the third embodiment.

Fig. 9 is a schematic diagram of closed stirrups in the longitudinal joint between the plates in the fourth embodiment.

Among them: 1—inverted T-shaped plate, 2—flange, 3—connecting rib extending from the lower part of the side of the plate, 4—connecting rib extending from the top of the plate, 5—connecting rib extending from the flange, 6—upper part of the side of the plate Protruding connecting ribs, 7—cast-in-situ concrete on the upper part of the slab and joints, 8—anti-collision wall, 9—U-shaped stirrups with unequal lengths on both legs, 10—closed stirrups inside the slab, 11—cast-in-place layer Top transverse reinforcement, 12—bridge deck, 13—enclosed stirrup in connecting joint.

detailed description

The following are specific embodiments of the present invention, and describe the technical solutions of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments.

Embodiment one

The slab bridge adopts the inverted T-shaped slab (1) shown in Figure 2. The width of the prefabricated slab is 99cm, and the thickness of the flange is 7.5cm. The convex middle part of the cross-section of the inverted T-shaped plate (1) is solid, and the connecting rib (3) protruding from the lower part of the side of the plate protrudes from the plate, and the overhang length is not less than the length of the flange (2) in the transverse bridge direction. Half, in order to further strengthen the connection with the adjacent board, the end of the connecting rib (3) protruding from the lower part of the side of the board increases an upward ninety-degree bend. The connecting rib (5) protruding from the flange is bent at 90 degrees in the cross section of the slab where it is located, so as to delay or avoid cracking along the new and old concrete joint surface here. The connecting ribs (4) protruding from the top of the slab can strengthen the bond between the cast-in-place concrete and the prefabricated inverted T-shaped slab (1), and enhance the overall mechanical performance. When assembling, the distance between the longitudinal centerlines of adjacent slabs is set to 1m. After assembling, longitudinal steel bars are bound in the longitudinal grooves formed by the convex parts of adjacent slabs. The spacing between the stirrups is 25cm. 7), the top surface of the cast-in-place concrete is directly used as the bridge deck, and the anti-collision wall (8) is constructed. After maintenance, it can be opened to traffic and put into use.

Embodiment two

This implementation example is an amendment to the first implementation example. The schematic diagram of the cross-section of the inverted T-shaped slab is shown in Figure 5, and the connecting rib (6) protruding from the upper part of the slab side is added to further enhance the strength of the new and old concrete joint surface. The schematic diagram of the corresponding slab beam reinforcement is shown in Figure 6. In order to facilitate the binding of steel bars and enhance the transverse strength of the slab, closed stirrups (10) are used in the slab. In addition, after pouring concrete (7) on the upper part of the cast-in-place slab and joints, paint waterproof paint, and then pave the asphalt concrete surface.

Embodiment Three

This embodiment is a modification to Embodiment 2. In order to ensure the reliability of the connecting bars, the ends of the connecting bars (3) protruding from the lower part of the side of the slab are bent upward at 90 degrees. In order to increase the span of the bridge, prestressed tendons are used at the bottom of the inverted T-shaped plate (1), and two U-shaped stirrups (9) with two limbs of unequal length are used to close the steel strand in the middle part of the plate. See Figure 8 for the schematic diagram of the No. 9 steel bar of the plate beam. The inverted T-shaped plate (1) is prefabricated by a pretensioning method. In order to reduce the on-site steel bar binding work, the on-site installed steel bars in the longitudinal joints between adjacent panels are made into steel bar cages, which can be directly placed in place after being transported to the site. See Figure 9 for a schematic diagram of closed stirrups in longitudinal joints between panels.

Claims (4)

1. A slab bridge, its upper stress structure is made of prefabricated inverted T-shaped slabs side by side, and the concrete poured above the slabs, it is characterized in that the upward protruding part of the middle part of the prefabricated inverted T-shaped slab cross section is solid and the width is not large Less than half of the width of the slab, each surface of the slab in contact with the cast-in-place concrete has connecting ribs protruding from the slab body, the connecting ribs on the side of the protruding part are located at the lower part of the side and the length extending from the edge of the slab into the adjacent slab is not less than the wing half of the edge extension. 2. The slab bridge according to claim 1, characterized in that the upper part of the side of the upward protruding part of the prefabricated inverted T-shaped plate also has connecting ribs. 3. The slab bridge according to claim 1, characterized in that the ends of the side connecting ribs are bent upward at 90 degrees to increase the connection performance. 4. The slab bridge according to claim 1, characterized in that the prefabricated slab is pre-tensioned, and the bottom is equipped with longitudinal prestressed ribs.