CN101935979A - Unreinforced prestressed concrete continuous girder bridge - Google Patents

Abstract

The invention relates to an unreinforced prestressed concrete cable-stayed bridge, the structure of which is: comprising a concrete main tower (1), a concrete main beam (2) and cable-stayed cables (5), characterized in that: the concrete main tower (1) ) is wrapped with prestressed tendons (3), and their upper and lower ends are fixed by anchors (4); the left and right ends of the concrete girder (2) are fixed by anchors (4). The difference between the present invention and the current prestressed reinforced concrete cable-stayed bridge is that ordinary steel bars in towers and beams are canceled, a large amount of steel materials are saved, and labor costs for processing and installing ordinary steel bars are saved, so the present invention has simple structure and low cost. , fast construction, convenient, stable and reliable, etc., can be widely used in bridges in roads and railways.

Description

Unreinforced prestressed concrete continuous girder bridge

technical field

The invention relates to the field of bridges, in particular to an unreinforced prestressed concrete cable-stayed bridge.

Background technique

The prestressed concrete cable-stayed bridge is a bridge type widely used in road and railway projects. It consists of a main tower, a main girder and cable-stayed cables. The main tower is made of concrete or prestressed concrete, and the main girder is made of prestressed concrete. Stay cables are made of steel wire or strands. Concrete is a kind of artificial stone with high compressive strength, low cost, good durability and convenient construction, so it is an ideal engineering material. However, concrete has a big disadvantage, that is, its tensile strength is very poor, its tensile strength is about 1/18 to 1/8 of the cubic compressive strength, and the ultimate tensile strain is less than 1/20 of the ultimate compressive strain. It can only stretch 0.10-0.15mm per meter. Therefore, concrete is particularly suitable for making pressure-bearing members. However, there are very few purely pressure-bearing components in engineering, and more are bending-shear, bending-torsion, bending-compression and other combined force-bearing members. Can appear already bigger compressive stress in these components, also can appear bigger stress of drawing. If the main girder of the cable-stayed bridge is only made of concrete, it is prone to damage and cannot bear much load. In order to overcome these shortcomings and make the main girder of reinforced concrete cable-stayed bridge more widely used in engineering, people form the main girder of prestressed concrete cable-stayed bridge by applying prestress in the main girder of reinforced concrete cable-stayed bridge.

The so-called prestressed concrete is the artificially introduced internal compressive stress in concrete or reinforced concrete, and its value and distribution can just offset the tensile stress generated by the applied load to a suitable level of reinforced concrete. Using prestressed concrete to build the main girder of a cable-stayed bridge has the advantages of improving the crack resistance and rigidity of the component, saving materials, reducing self-weight, reducing the vertical shear force and main tensile stress of the beam, and the quality of the bridge is safe and reliable. But the present prestressed concrete cable-stayed bridge main girder is still equipped with a large amount of ordinary steel bars, in fact it is a prestressed concrete cable-stayed bridge with steel bars, or prestressed reinforced concrete cable-stayed bridge main girder. Prestressed reinforced concrete cable-stayed bridges are expensive and difficult to construct due to the configuration of a large number of ordinary steel bars.

Contents of the invention

The technical problem to be solved by the present invention is to provide a prestressed concrete cable-stayed bridge without reinforcement, so as to overcome the defects of high cost and troublesome construction of the current prestressed reinforced concrete cable-stayed bridge.

The present invention adopts the following technical solutions to solve the technical problems: it includes a concrete main tower, a concrete main beam and stay cables. Prestressed tendons are wrapped around the periphery of the concrete main tower, and their upper and lower ends are fixed by anchors. The left and right ends of the concrete main beam are fixed by anchors.

The concrete main tower can be prestressed through steel strands without ordinary steel bars. The steel strand is located in the reserved pipeline of the concrete main tower, and the two ends of the steel strand are fixed by anchors.

The concrete main girder can be prestressed through steel strands without ordinary steel bars. The steel strand is located in the reserved pipe of the concrete main girder, and the two ends of the steel strand are fixed by anchors.

Compared with the prior art, the present invention has the following main advantages:

It is only made of plain concrete, prestressed steel strands, and stay cables, and does not need to arrange ordinary steel bars. It can ensure that the bridge structure is simple, strong, stable and reliable, and has the advantages of fast, convenient and low cost construction.

Description of drawings

Fig. 1 is the facade structure schematic diagram of unreinforced prestressed concrete cable-stayed bridge;

Figure 2 is a schematic diagram of the cross-sectional structure of an unreinforced prestressed concrete cable-stayed bridge.

In the figure: 1. Concrete main tower; 2. Concrete main beam; 3. Prestressed tendons; 4. Anchors; 5. Stay cables.

Detailed ways

The unreinforced prestressed concrete cable-stayed bridge provided by the present invention is made up of concrete main tower 1, concrete girder 2, prestressed tendon 3, anchorage 4 and stay cable 5, specifically as shown in Figure 1 and Figure 2: concrete The main tower 1 and the concrete main girder 2 are integrated with a stay cable 5 to form a cable-stayed bridge that can be used for traffic or pedestrians. The prestressed tendons 3 are wrapped around the periphery of the concrete main tower 1, and are fixed by anchors 4 at their upper and lower ends. The left and right ends of the concrete girder 2 are fixed by anchors 4 .

The innovation of the invention lies in the structure; each component can be prepared by conventional techniques.

The concrete main tower 1 is used to bear the load transmitted from the stay cables and the main girder. Reserve a pipeline during the preparation of the concrete main tower 1, pass the steel strand through the pipeline and apply tension with a jack, then plug the anchor on the pipeline and loosen the jack, at this time the steel strand retracts to press the anchor , the pressure is transmitted to the concrete main tower 1, which is used to resist the tensile stress generated by the load to form the unreinforced prestressed concrete main tower 1.

The concrete main tower can be prepared by conventional techniques, for example: 450kg of cement, 180kg of water, 700kg of sand, and 1200kg of gravel can be mixed evenly, and then the concrete main tower 1 can be obtained after vibrating, forming and curing.

The concrete girder 2 is used for driving or pedestrians. Reserve the pipeline during the preparation of the concrete main beam 2, pass the steel strand through the pipeline and apply tension with a jack, then plug the anchor on the pipeline, and loosen the jack, at this time, the steel strand retracts, causing the anchor to be compressed. The pressure is transmitted to the concrete to resist the tensile stress generated by the load to form the unreinforced prestressed concrete main beam 2.

The concrete main girder can be prepared by a conventional process, for example, after mixing 480kg of cement, 185kg of water, 660kg of sand, and 1100kg of crushed stone, the concrete main beam can be obtained after vibrating, forming and curing.

The prestressed tendons 3 are made of steel wire or steel strands for applying prestress.

The anchor 4 is a steel nut or a steel clip made of steel or alloy steel for anchoring prestressed tendons.

The stay cables 5 are made of steel wires or steel strands and are used to connect the concrete tower 1 and the concrete girder 2 to form an unreinforced prestressed concrete cable-stayed bridge that can be used for traffic or pedestrians.

The proportioning of above-mentioned cement, water, sand, gravel can be determined by actual situation.

The difference between the present invention and the current prestressed reinforced concrete cable-stayed bridge is that ordinary steel bars in towers and beams are canceled, a large amount of steel materials are saved, and labor costs for processing and installing ordinary steel bars are saved, so it has the advantage of lower cost ; Because the time for making and installing ordinary steel bars is saved, the construction is fast and convenient; because pre-stressing for resisting external forces is applied. It can ensure that the engineering structure is strong, stable and reliable. It can be widely used in bridges in roads and railways.

Claims (5)

1. tendon-free prestressed concrete cable stayed bridge, comprise concrete king-tower (1), concrete girder (2) and suspension cable (5), it is characterized in that: be enclosed with presstressed reinforcing steel (3) in the periphery of concrete king-tower (1), and fixing at their two ends up and down by ground tackle (4); The two ends, the left and right sides of concrete girder (2) are fixing by ground tackle (4).

2. tendon-free prestressed concrete cable stayed bridge according to claim 1 is characterized in that: concrete king-tower (1) applies prestressing force by steel strand, no plain bars.

3. tendon-free prestressed concrete cable stayed bridge according to claim 2 is characterized in that: described steel strand are arranged in the reservation pipeline of concrete king-tower (1), and the two ends of these steel strand are fixed by ground tackle.

4. tendon-free prestressed concrete bridge according to claim 1 is characterized in that: concrete girder (2) applies prestressing force by steel strand, no plain bars.

5. tendon-free prestressed concrete cable stayed bridge according to claim 4 is characterized in that: described steel strand are arranged in the reservation pipeline of concrete girder (2), and the two ends of these steel strand are fixed by ground tackle.

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