Railway concrete simply-supported box girder system of ultrahigh-strength prestressed system
By adopting a hybrid design of a first-tension and later-tension ultra-high-strength prestressing system in the railway concrete simple-supported box girder, the problems of large spatial structure size and uneven stress in the anchoring part in the prior art are solved, and the effect of reducing the amount of concrete material and improving technical economy is achieved.
Patent Information
- Application Number
- CN202323565947.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-26
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2033-12-26
AI Technical Summary
The existing railway concrete simple-supported box beam has a large spatial structure size at the anchoring site, and the thickness of the beam end bottom plate and web is high, resulting in a large self-weight of the overall structure, uneven stress in the anchoring area, high chamfer stress on the inner side of the bottom plate and web, and there is a risk of cracking during final tensioning of prestress.
The first-tension and later-tension ultra-high-strength prestressing system is used. The box beam bottom prestressing beam uses first-tension steel strands, and the web prestressing beam uses second-tension steel strands. The first-tension steel strands are arranged evenly along the longitudinal direction of the bottom plate, and the back-tension steel strands are arranged in a folded beam structure in the longitudinal direction of the web.
The size of the anchoring area at the end of the beam is reduced, the amount of concrete material is used, the technical economy of the railway simple supporting box beam is improved, the stress on the anchoring area is uniform, the chamfering stress on the inner side of the bottom plate and web is reduced, and the risk of cracking during final tensioning of prestress is reduced.
Smart Images
Figure CN222648562U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of bridges, in particular to a railway concrete simply supported box girder system of an ultra-high strength prestressed system. Background Art
[0002] Since the beginning of the 21st century, my country's high-speed railway has entered the fast lane of construction and development, and the construction technology of railway simply supported box girders has also developed rapidly. Although the simply supported box girder is heavy, the prefabrication and erection construction has high requirements for transportation and erection equipment, the beam manufacturing site occupies a large area, and the project investment is large; however, the simply supported box girder has a simple and beautiful appearance, good integrity, high structural rigidity, excellent dynamic performance, small residual creep of the beam body, and is convenient for ballastless track laying and sound barrier installation. The bottom width of the box girder is small, the pier structure size is small, and the bridge landscape is good. The whole-hole prefabricated simply supported box girder reduces the amount of cast-in-place engineering at the bridge site, and the maintenance and repair during operation requires less labor and low cost. It has been widely used in my country's high-speed, intercity, and urban (suburban) railway construction projects. In recent years, newly started passenger and freight railway projects have gradually begun to use simply supported box girders.
[0003] Existing railway concrete simply supported box girders mostly use 1860MPa, 15.20mm diameter post-tensioned steel strands. The spatial structural dimensions of the anchoring part are large, the thickness of the beam end bottom plate and the web plate are thick, the amount of concrete material is high, and the overall structure is heavy. The anchoring area of the beam end is unevenly stressed, the stress of the inner chamfer of the bottom plate and web plate of the beam end and the arc chamfer stress of the bottom plate manhole are high, and the local part of the beam end has a certain risk of cracking during the final tensioning of the prestress.
[0004] In order to solve the above problems, a railway concrete simply supported box girder system with an ultra-high strength prestressed system is needed. Utility Model Content
[0005] The utility model is to solve the problems in the prior art that the anchoring space dimensions of the existing simply supported box beam are large, the thickness of the beam end bottom plate and the web plate are both thick, the amount of concrete material used is high, and the overall structure is heavy. At the same time, the anchoring area of the beam end is subjected to uneven force, the stress of the inner chamfer of the bottom plate and the web plate at the beam end and the arc chamfer stress of the bottom plate entering the manhole are both high, and the local part of the beam end has a certain risk of cracking during the final tensioning of the prestress. The utility model provides a railway concrete simply supported box beam system with an ultra-high strength prestressed system, which solves the problems of the prior art.
[0006] The utility model provides a railway concrete simply supported box girder system of an ultra-high strength prestressed system, comprising a top plate, a first flange plate, a second flange plate, a first web plate, a second web plate, a bottom plate and a post-tensioning mechanism, wherein the top plate and the bottom plate are both arranged transversely, and both the top plate and the bottom plate are strip-shaped plates, the top plate is arranged above the bottom plate, the first web plate and the second web plate are both arranged vertically, the first web plate and the second web plate are relatively arranged between the bottom surface of the top plate side edge and the corresponding top surface of the bottom plate side edge, the first flange plate and the second flange plate are respectively arranged on both sides of the top plate, the top surface of the first flange plate, the top surface of the second flange plate and the top surface of the top plate are arranged coplanarly, the first web plate and the second web plate are provided with prestressed pipes, and post-tensioned steel strands are both arranged in the prestressed pipe of the first web plate and the prestressed pipe of the second web plate, the post-tensioning mechanism is arranged at both ends of the prestressed pipe of the first web plate to tension the post-tensioned steel strands, and the post-tensioning mechanism is arranged at both ends of the prestressed pipe of the second web plate to tension the post-tensioned steel strands.
[0007] The utility model describes a railway concrete simply supported box girder system of an ultra-high strength prestressed system. As a preferred embodiment, the bottom plate is provided with pre-stressed steel strands, which are arranged uniformly and parallel to each other along the longitudinal direction of the bottom plate. The diameter of the pre-stressed steel strands is 17.8 mm or 21.8 mm, and the strength of the pre-stressed steel strands is 1960 MPa.
[0008] The utility model discloses a railway concrete simply supported box girder system of an ultra-high strength prestressed system, in which, as a preferred embodiment, the strength of the post-tensioned steel strands is 2200MPa-2400MPa.
[0009] The utility model discloses a railway concrete simply supported box girder system of an ultra-high strength prestressed system. As a preferred embodiment, the connection between the first web and the bottom plate and the connection between the second web and the bottom plate are both provided with chamfers.
[0010] The utility model discloses a railway concrete simply supported box girder system of an ultra-high strength prestressed system. As a preferred embodiment, the post-tensioned steel strands are arranged in a folded line structure in the longitudinal direction of the first web and the second web.
[0011] The utility model discloses a railway concrete simply supported box girder system of an ultra-high strength prestressed system. As a preferred embodiment, the pre-tensioned steel strands are arranged in two rows in the bottom plate.
[0012] The beneficial effects of the utility model are as follows:
[0013] The utility model adopts a mixture of pre-tensioned and post-tensioned ultra-high strength prestressed systems. The prestressed tendons of the box girder bottom plate adopt pre-tensioned steel strands, and the prestressed tendons of the web plate adopt post-tensioned steel strands. The pre-tensioned and post-tensioned ultra-high strength prestressed systems are mixed, which reduces the size of the anchorage area at the beam end, reduces the number of concrete projects, and improves the technical and economic benefits of the railway simply supported box girder. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a schematic diagram of a railway concrete simply supported box girder system of an ultra-high strength prestressed system;
[0015] Figure 2 It is a perspective schematic diagram of the bottom plate of a railway concrete simply supported box girder system of an ultra-high strength prestressed system;
[0016] Figure 3 It is a schematic side view of a railway concrete simply supported box girder system with an ultra-high strength prestressed system.
[0017] Reference numerals:
[0018] 1. Top plate; 2. First flange plate; 3. Second flange plate; 4. First web plate; 5. Second web plate; 6. Bottom plate; 7. Post-tensioning mechanism. DETAILED DESCRIPTION
[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.
[0020] Example 1
[0021] like Figure 1 As shown, a railway concrete simply supported box girder system of an ultra-high strength prestressed system comprises a top plate 1, a first flange plate 2, a second flange plate 3, a first web plate 4, a second web plate 5, a bottom plate 6 and a post-tensioning mechanism 7. The top plate 1 and the bottom plate 6 are both arranged horizontally, and both the top plate 1 and the bottom plate 6 are strip-shaped plates. The top plate 1 is arranged above the bottom plate 6, and the first web plate 4 and the second web plate 5 are both arranged vertically. The first web plate 4 and the second web plate 5 are relatively arranged between the bottom surface of the side edge of the top plate 1 and the corresponding top surface of the side edge of the bottom plate 6. The edge plate 2 and the second flange plate 3 are respectively arranged on both sides of the top plate 1, the top surface of the first flange plate 2, the top surface of the second flange plate 3 and the top surface of the top plate 1 are arranged coplanarly, the first web 4 and the second web 5 are provided with prestressed pipes, and the prestressed pipes of the first web 4 and the prestressed pipes of the second web 5 are both provided with post-tensioned steel strands, the post-tensioning mechanism 7 is arranged at both ends of the prestressed pipes of the first web 4 to tension the post-tensioned steel strands, and the post-tensioning mechanism 7 is arranged at both ends of the prestressed pipes of the second web 5 to tension the post-tensioned steel strands.
[0022] like Figure 2 As shown, the bottom plate 6 is provided with pre-tensioned steel strands, which are arranged uniformly and parallel to each other along the longitudinal direction of the bottom plate 6, with a diameter of 17.8 mm or 21.8 mm and a strength of 1960 MPa. The strength of the post-tensioned steel strands is 2200 MPa to 2400 MPa.
[0023] Chamfers are provided at the connection points between the first web 4 and the bottom plate 6 and at the connection points between the second web 5 and the bottom plate 6 .
[0024] like Figure 3 As shown, the post-tensioned steel strands are arranged in a folded line structure in the longitudinal direction of the first web 4 and the second web 5. The pre-tensioned steel strands are arranged in two rows in the bottom plate 6.
[0025] The concrete simply supported box girder system described in this embodiment has the following specific construction steps:
[0026] S1. The bottom plate of the box girder adopts a pre-stressed system with a diameter of 17.8mm or 21.8mm and a strength of 1960MPa. The strands are arranged in a straight line and are tensioned and anchored to the bottom form of the box girder before concrete pouring.
[0027] S2. The web plate adopts a post-tensioning prestressing system with a strength of 2200MPa to 2400MPa, and prestressed pipes are reserved before concrete pouring;
[0028] S3. Pour the box girder concrete. When the design strength reaches 80%, the prestressed tendons of the bottom plate are released and the bottom plate prestress is applied. The box girder is lifted from the beam manufacturing pedestal to the beam storage pedestal.
[0029] S4. The web prestressed pipes are threaded through the bundles. After the concrete reaches 100% of the design strength, the web prestressed steel bundles are tensioned, the web prestress is applied, and the web prestressed pipes are grouted and anchored.
[0030] Compared with the existing 1860MPa prestressed system, this embodiment saves the spatial structural dimensions of the anchoring part, the thickness of the bottom plate at the beam end is reduced by 30% (700mm reduced to 450mm), and the thickness of the web is reduced by 10% (950mm reduced to 850mm); the uniform cross-sectional structural dimensions of the middle part are saved, the thickness of the bottom plate is reduced from 280mm to 240mm, and the thickness of the web is reduced from 360mm to 330mm~310mm, saving the amount of concrete material.
[0031] The pre-tensioning high-strength prestressed system makes the stress in the anchorage area of the beam end more uniform, reduces the stress of the inner chamfer of the bottom plate and web of the beam end by 30%, reduces the stress of the arc chamfer of the bottom plate manhole by 30%, and reduces the risk of cracking in local parts of the beam ends of existing railway simply supported box girders during the final prestressing.
[0032] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A railway concrete simply supported box girder system of ultra-high strength prestressed system, characterized by: The invention comprises a top plate (1), a first flange plate (2), a second flange plate (3), a first web plate (4), a second web plate (5), a bottom plate (6) and a post-tensioning mechanism (7), wherein the top plate (1) and the bottom plate (6) are both arranged transversely, the top plate (1) and the bottom plate (6) are both strip-shaped plates, the top plate (1) is arranged above the bottom plate (6), the first web plate (4) and the second web plate (5) are both arranged vertically, the first web plate (4) and the second web plate (5) are arranged relatively between the bottom surface of the side edge of the top plate (1) and the top surface of the side edge of the corresponding bottom plate (6), the first flange plate (2) and the second flange plate (3) are arranged horizontally, and the first web plate (4) and the second web plate (5) are arranged horizontally. The plates (3) are respectively arranged on both sides of the top plate (1); the top surface of the first flange plate (2), the top surface of the second flange plate (3) and the top surface of the top plate (1) are arranged coplanarly; the first web plate (4) and the second web plate (5) are provided with prestressed pipes; the prestressed pipes of the first web plate (4) and the prestressed pipes of the second web plate (5) are both provided with post-tensioned steel strands; the post-tensioning mechanism (7) is arranged at both ends of the prestressed pipe of the first web plate (4) to tension the post-tensioned steel strands; and the post-tensioning mechanism (7) is arranged at both ends of the prestressed pipe of the second web plate (5) to tension the post-tensioned steel strands.
2. The ultra-high strength prestressed railway concrete simply supported box girder system according to claim 1, characterized in that: The base plate (6) is provided with pre-tensioned steel strands, which are arranged uniformly and parallel to each other along the longitudinal direction of the base plate (6), have a diameter of 17.8 mm or 21.8 mm, and have a strength of 1960 MPa.
3. The ultra-high strength prestressed railway concrete simply supported box girder system according to claim 1, characterized in that: The strength of the post-tensioned steel strand is 2200MPa to 2400MPa.
4. The ultra-high strength prestressed railway concrete simply supported box girder system according to claim 1, characterized in that: Chamfers are provided at the connection points between the first web (4) and the bottom plate (6), and at the connection points between the second web (5) and the bottom plate (6).
5. The ultra-high strength prestressed railway concrete simply supported box girder system according to claim 1, characterized in that: The post-tensioned steel strands are arranged in a folded line structure in the longitudinal direction of the first web (4) and the second web (5).
6. The ultra-high strength prestressed railway concrete simply supported box girder system according to claim 2, characterized in that: The pre-tensioned steel strands are arranged in two rows in the bottom plate (6).