CN219451606U

CN219451606U - Device for preventing prestressed beam from being subjected to inverted arch after unloading

Info

Publication number: CN219451606U
Application number: CN202320413826.5U
Authority: CN
Inventors: 康亚强; 陶然; 唐虎; 杨镇; 于越; 苏自强; 肖文辉; 王谦; 兰泓静
Original assignee: China Railway Design Corp
Current assignee: China Railway Design Corp
Priority date: 2023-03-07
Filing date: 2023-03-07
Publication date: 2023-08-01
Anticipated expiration: 2033-03-07

Abstract

The utility model belongs to the technical field of civil engineering structures, and discloses a device for preventing a prestressed beam from being subjected to inverted arch after unloading, wherein the device is provided with steel strands and steering blocks, the steering blocks are arranged on two sides of the top of the existing prestressed beam, and the steel strands bypass the existing prestressed beam outside the steering blocks; the two ends of the steel strand are connected with a harness cord screw through connectors, and the lower end of the harness cord screw is fixedly connected with the bottom plate structure. The utility model is used for the condition that the unloading level of the existing prestressed beam is higher, and can apply downward load in stages according to the unloading process, and reduce the downward load in stages along with the construction of a newly built structure. The steel stranded wire is wound on the beam, the steel stranded wire is connected with Gao Jiangtong wires, and the construction such as tensioning is convenient by adopting an anchor. Therefore, the utility model has the characteristics of reliable stress, convenient construction, step loading and step unloading, and can ensure the safety of the reconstructed prestressed beam structure and prevent engineering safety accidents.

Description

Device for preventing prestressed beam from being subjected to inverted arch after unloading

Technical Field

The utility model belongs to the technical field of civil engineering structures, and particularly relates to a device for preventing an arch from being inverted after a prestressed beam is unloaded.

Background

Along with the construction of large-scale building structures in China, a large number of prestress structures are built. As the engineering of reconstruction increases, so too does the engineering of reinforcement and reconstruction involving prestressed concrete structures.

In the engineering of the prestress structure, unloading conditions of the existing prestress beam can be met. Because the prestress in the beam is in a tensioned state, similar to a tensioned "rubber band," an upward arching force (i.e., prestress "equivalent load") is generated on the beam. If the unloading level of the prestressed beam is higher, the prestressed beam can be deformed in an inverted arch and cracked, and engineering safety accidents can be caused when serious, so that great loss is caused. How to ensure the safety of the structure of the prestressed beam after unloading and what measures are taken for the prestressed beam in the transformation process are important problems for the transformation of the prestressed concrete structure. At present, for the engineering of modifying the prestressed concrete structure, the measures for preventing the prestressed beam from generating an inverted arch after unloading are still in the blank field of technical measures in China.

As can be seen from the above, the prior art has the following problems: in the unloading process of the prestressed girder, a device for preventing the prestressed girder from generating an inverted arch is absent, and particularly when the unloading level is high, engineering safety accidents are easy to occur, so that great loss is caused.

The difficulty of solving the technical problems is that: the method provides measures with high safety, good economy and strong operability, and particularly provides measures for applying downward load in stages and constructing with a newly built structure aiming at the unloading process of the prestressed beam, and withdrawing the downward load in stages.

Disclosure of Invention

To overcome the problems in the related art, the disclosed embodiments of the present utility model provide a device for preventing an invert from occurring after unloading of a prestressed girder. The technical scheme is as follows:

an apparatus for preventing arching after unloading of a prestressed girder is provided with:

steel strand wires and steering blocks;

the steering blocks are arranged on two sides of the top of the existing prestressed beam, and the steel stranded wires bypass the existing prestressed beam outside the steering blocks;

the two ends of the steel strand are connected with the harness cord screw through connectors, and the lower end of the harness cord screw is fixedly connected with the bottom plate structure.

In one embodiment, a special anchor for jack tensioning the steel strand is arranged at the lower part of the steel strand.

In one embodiment, the steering block is a cambered steel plate structure.

In one embodiment, the Gao Jiangtong wires are implanted into the bottom plate structure by using A-level bar planting glue.

In one embodiment, the connector is divided into an upper section and a lower section, the upper section and the lower section are connected through screws, the upper section and the steel strand are fixed through steel wedge plates, and the lower section and the harness cord screw are fixed through threads.

By combining all the technical schemes, the utility model has the advantages and positive effects that:

the utility model is used for the condition that the unloading level of the existing prestressed beam is higher, and can apply downward load in stages according to the unloading process, and reduce the downward load in stages along with the construction of a newly built structure. The steel stranded wire is wound on the beam, the steel stranded wire is connected with Gao Jiangtong wires, and the construction such as tensioning is convenient by adopting an anchor. Therefore, the utility model has the characteristics of reliable stress, convenient construction, step loading and step unloading, and can ensure the safety of the reconstructed prestressed beam structure and prevent engineering safety accidents.

The utility model is applied to the engineering of the passenger tunnel reconstruction of a certain high-speed rail station. The prestressed beam with the passenger tunnel span of 27.3m has the inverted arch displacement of only 1.7mm after unloading and is far smaller than the allowable deformation value of 15mm. The utility model effectively ensures the safety of the structure in the reconstruction process, has strong operability and lower manufacturing cost.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure of the utility model as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure.

FIG. 1 is a schematic view of an apparatus for preventing arching after unloading of a prestressed girder according to an embodiment of the present utility model;

FIG. 2 is a cross-sectional view of an apparatus for preventing arching after unloading of a prestressed girder according to an embodiment of the present utility model;

FIG. 3 is a schematic diagram of an embodiment of the present utility model prior to engineering;

FIG. 4 is a schematic diagram of an embodiment of the present utility model after engineering;

FIG. 5 is a schematic view of a steering block according to an embodiment of the present utility model;

fig. 6 is a schematic structural diagram of a connector according to an embodiment of the present utility model;

FIG. 7 is a schematic view of an anchor according to an embodiment of the present utility model;

in the figure: 1. steel strand; 2. existing prestressed beams; 3. a steering block; 4. a connector; 5. an anchor; 6. a harness cord screw; 7. a base plate structure; 8. the existing structure; 9. a train; 10. and (5) newly building a structure.

Detailed Description

In order that the above objects, features and advantages of the utility model will be readily understood, a more particular description of the utility model will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present utility model. The utility model may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit or scope of the utility model, which is therefore not limited to the specific embodiments disclosed below.

As shown in fig. 1 to 7, the device for preventing the prestressed beam from being subjected to inverted arch after unloading is provided with a steel strand 1 and a steering block 3, wherein the steering block 3 is arranged on two sides of the top of the existing prestressed beam 2, and the steel strand 1 bypasses the existing prestressed beam 2 outside the steering block 3; the two ends of the steel strand 1 are connected with a harness cord screw 6 through connectors 4, and the lower end of the harness cord screw 6 is fixedly connected with a bottom plate structure 7. The Gao Jiangtong wires are implanted into the bottom plate structure 7 by adopting A-level bar planting glue.

The lower part of the steel strand 1 in the embodiment of the utility model is provided with an anchorage device 5 for jack tensioning the steel strand 1. The steering block 3 is of a cambered surface steel plate structure.

Examples: the steel strand adopts a 1X 7 standard steel strand 1, the nominal diameter is 15.2mm, and the ultimate strength standard value is 1860MPa. Gao Jiangtong filaments have a diameter of 27mm and a strength rating of 8.8. Each prestress beam is provided with 20 groups of steel strands 1, and the spacing is 450mm. With the existing structure 8 being removed step by step, the load of the prestressed beams is 1000kN, 1400kN and 1800kN. The steel strand 1 is tensioned by a jack, and the corresponding tensioning forces are 2000kN, 1500kN and 700kN. With the construction of the new structure 10, the steel strand 1 correspondingly reduces the tensile force by loosening the nuts on the connector 4.

The working principle of the utility model is as follows: the utility model utilizes the tensioned steel strand 1 to gradually counteract the unloading effect generated by the dismantling of the existing structure 8, and gradually loosens the steel strand 1 along with the establishment of the newly built structure 10.

The load of the train 9 is the main load of the structure, before the existing structure 8 is dismantled, the steering blocks 3 are arranged on two sides of the top of the existing prestress beam 2, the steering blocks 3 are welded into cambered surfaces by steel plates and are used for steering the steel stranded wires 1, and the steel stranded wires are fixed on the beam side by chemical anchors. A wire-passing screw rod 6 is implanted on the bottom plate structure 7, and the bar-planting glue adopts A-level glue. The steel strand 1 bypasses the existing prestress beam 2 and the steering block 3 and is connected with Gao Jiangtong wires through a connector 4. One end of the connector 4 is fixed with the steel strand 1 through a steel wedge piece, and the other end is fixed with the Gao Jiangtong wire through threads. Along with the dismantling of the existing structure 8, the prestress beam is unloaded, meanwhile, the steel strand 1 is tensioned in stages at the anchor 5 by using a jack, and the tensioning force is determined through calculation according to the unloading load. The anchor 5 is provided with a forward steel strand 1 pulling hole and two reverse steel strand 1 fixing holes. After the existing structure 8 is dismantled, the steel strand 1 is tensioned. With the construction of the construction structure 10, the steel strand 1 is gradually loosened by the nuts on the connectors 4 until the newly built structure 10 is completed. Finally, the exposed steel strand 1, the harness cord screw 6 and other components are removed.

The utility model can be used for the reconstruction engineering of the existing structure 8 and also can be used as a temporary measure for preventing the occurrence of the inverted arch in the construction process of the newly built prestressed structural beam.

While the utility model has been described with respect to what is presently considered to be the most practical and preferred embodiments, it is to be understood that the utility model is not limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications, equivalents, and alternatives falling within the spirit and scope of the utility model.

Claims

1. The device for preventing the prestressed beam from being subjected to inverted arch after unloading is characterized by comprising steel strands (1) and steering blocks (3), wherein the steering blocks (3) are arranged on two sides of the top of the existing prestressed beam (2), and the steel strands (1) bypass the existing prestressed beam (2) outside the steering blocks;

both ends of the steel strand wires (1) are connected with the harness cord screw (6) through connectors (4), and the lower end of the harness cord screw (6) is fixedly connected with the bottom plate structure (7).

2. Device for preventing the occurrence of arching after unloading of prestressed beams according to claim 1, characterized in that the lower part of the steel strand (1) is provided with an anchorage (5), said anchorage (5) being used for jack-stretching the steel strand (1).

3. Device for preventing the occurrence of an arching after unloading of a prestressed girder according to claim 1, characterized in that said turning block (3) is of cambered steel plate construction.

4. Device for preventing the occurrence of arching after unloading of prestressed beams according to claim 1, characterized in that the connector (4) is divided into an upper section and a lower section, between which the upper section and the lower section are connected by means of screws, the upper section is fixed by means of steel wedge plates with the steel strand (1), and the lower section is fixed by means of screws with the through-screw (6).