CN205024584U - Pre -stressed reinforcement's segmentation anchor structure in case roof beam - Google Patents

Abstract

The utility model relates to a segmental anchoring structure of a prestressed beam in a box girder. The structure mainly includes a main anchor block and an auxiliary anchor block on the bottom plate of the box girder, as well as a main anchor plate and an auxiliary anchor plate. Wherein the main anchor plate and the auxiliary anchor plate are arranged on the main anchor block and the auxiliary anchor block respectively. A small part of the prestressing beam is anchored to the auxiliary anchor block. Compared with the traditional anchoring method, the utility model can effectively prevent the cracks in the anchoring area due to tension and prestress, and also reduce the anti-cracking steel bars around the anchor block, which is convenient for concrete pouring and vibration, and also reduces the size of the anchor block. It is convenient for construction tensioning operation. The durability and service life of the structure can be increased.

Description

A Segmental Anchorage Structure of Prestressed Beam in Box Girder

technical field

The utility model relates to a segmental anchoring structure of a prestressed beam in a box girder, which belongs to the field of bridge engineering.

Background technique

Prestressed concrete members have good crack resistance and high rigidity. Prestressed concrete has been widely used in the field of bridge engineering. However, a large number of prestressed beams are required in long-span bridges, and the tension tonnage is large. Therefore, after the prestressed steel bars are tensioned and anchored in the bridge girder slab, a tensile stress zone will appear on the girder slab outside the anchor block, which is easy to appear. crack. The large tonnage tension also requires the addition of anti-cracking reinforcement near the anchor block, resulting in dense reinforcement in this area, which makes it difficult to vibrate during the concrete pouring process and affects the quality of the concrete. Since the prestressed beam contains more prestressed tendons, large-tonnage tensioning equipment needs to enter the inside of the box girder, and the tensioning operation is inconvenient.

Utility model content

In order to solve the deficiencies of the prior art, the utility model provides a segmented anchoring structure of prestressed beams in a box girder.

The purpose of this utility model can be achieved through the following technical solutions. A segmental anchoring structure of prestressed beams in a box girder, mainly including a main anchor block and an auxiliary anchor block on a bottom plate, and a main anchor plate and an auxiliary anchor plate, wherein the main anchor plate and the auxiliary anchor plate are respectively arranged on the main anchor block and auxiliary anchor blocks. The prestressed bundle in the beam slab is anchored in two parts respectively into the main anchor block and the auxiliary anchor block. Most of the prestressed tendons are still anchored into the main anchor block, and a small amount of prestressed tendons are anchored into the auxiliary anchor block. The clear distance between the auxiliary anchor block and the main anchor block is at least the length of one main anchor block. In this way, behind the main anchor block, there is precompressive stress exerted by the prestressed tendons in the auxiliary anchor block, which can greatly improve the stress state around the main anchor block and avoid concrete cracking.

Further, the structure is equipped with prestressed channel branch connectors at the prestressed steel strands, so as to connect the corresponding prestressed channel bellows of each section. For steel corrugated pipes, iron sheets can be used to make prestressed channel branch connectors.

With this scheme, when stretching the prestressed tendons, the prestressed tendons inside the main anchor block are stretched first, and then the prestressed tendons inside the auxiliary anchor block are stretched. The anchored prestressed tendons can also be slow bonded prestressed tendons, and the slow bonded prestressed tendons will be installed with the steel bars, and then poured concrete. After the concrete reaches the tensile strength requirement, the retarding binder designed at this time has not yet solidified, and the prestressed tensioning operation is completed before it solidifies.

The segmental anchoring structure of the prestressed beam in the box girder can also be arranged on the top plate of the box girder.

Compared with the traditional anchoring method, the utility model can effectively prevent the cracks in the anchorage area due to tension and prestress, and also reduce the anti-cracking steel bars around the anchor block, which is convenient for concrete pouring and vibration, and also reduces the size of the anchor block. It is convenient for construction tensioning operation. Thereby the durability and service life of the structure can be increased.

Description of drawings

Fig. 1 is the schematic diagram of the utility model,

The schematic diagram of the utility model is adopted at both ends of the steel beam on the bottom plate of Fig. 2 box girder,

The schematic diagram of the utility model being adopted at both ends of the beam on the top plate of the box girder of Fig. 3

Figure 4 is a schematic diagram of embodiment three,

Figure 5 Schematic diagram of prestressed channel branch connectors,

In the above figure: 1—main anchor block, 2—auxiliary anchor block, 3—prestressed beam, 4—bottom plate of box girder, 5—main anchor plate, 6—auxiliary anchor plate, 7—short split of prestressed beam, 8—the long branch of the prestressed beam, 9—the top plate of the box girder, 10—the anchor plate at the end of the beam, 11—the branch connector of the prestressed channel.

detailed description

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

Embodiment one

The structural diagram of this embodiment is shown in Figure 2. On the bottom plate (4) of the box girder, a prestressed beam (3) is installed. For cracking, set the auxiliary anchor block (2) behind the main anchor block (1), and the net distance between the main anchor block (1) and the auxiliary anchor block (2) is the length of one main anchor block (1). Correspondingly, 4 steel strands are taken out from the prestressed bundle (3) and anchored on the auxiliary anchor plate (6), and most of the rest are still anchored on the main anchor plate (5). During construction, first penetrate the long branch (8) of the prestressed beam, and then penetrate the short branch (7) of the prestressed beam. During stretching, the short sub-bundle (7) of the prestressed beam is tensioned earlier, and then the long sub-bundle (8) of the prestressed beam is tensioned. Steel bellows are used for the prestressed channel, and the prestressed channel branch connectors (11) shown in Figure 5 are made in advance with iron sheets. When installing the bellows, the prestressed channel branch connectors (11) are used to connect each section of the bellows.

Embodiment two

The structure diagram of this embodiment is shown in Fig. 3 and Fig. 5. The difference from the second embodiment is that the structure of the utility model is arranged on the top plate (9) of the box girder, and the bellows are made of plastic bellows. Correspondingly, the prestressed channel branch connector (11) is also made of plastic. When installing the bellows, use the prestressed channel branch connector (11) to connect each section of the plastic bellows.

Embodiment three

The schematic diagram of the structure in this embodiment is shown in Figure 4. At the end of the box girder floor, the prestressed beam is anchored to the beam end anchor plate (10) of the end section of the floor, and the inner end adopts the stress beam of the present utility model. Segmented anchorage structure.

Claims (2)

1. A segmented anchorage structure of prestressed bundle in a box girder, mainly comprising main anchor block and auxiliary anchor block on the box girder base plate, base plate, and main anchor plate and auxiliary anchor plate, it is characterized in that: in the prestressed beam A small amount of prestressed tendons are anchored in the auxiliary anchor block at the rear of the main anchor block, and the net distance between the auxiliary anchor block and the main anchor block is at least the length of one main anchor block. 2. The segmental anchoring structure of prestressed beams in a kind of box girder according to claim 1, characterized in that: said structure is equipped with prestressed channel branch connectors at the prestressed steel beams to connect The corresponding prestressed channel bellows of each section.