CN111424525A - Large-span superposed beam of high-speed railway and construction method thereof - Google Patents
Large-span superposed beam of high-speed railway and construction method thereof Download PDFInfo
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D2/00—Bridges characterised by the cross-section of their bearing spanning structure
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Abstract
The invention relates to bridge engineering, in particular to a large-span superposed beam of a high-speed railway and a construction method thereof. The large-span superposed beam of the high-speed railway comprises an upper part and a lower part made of ultra-high performance concrete, wherein the upper part is supported on the lower part, a shear-resistant and anti-pulling member is arranged between the lower part and the upper part, the upper end of the shear-resistant and anti-pulling member extends into the upper part and is fixedly connected with the upper part, and the lower end of the shear-resistant and anti-pulling member extends into the lower part and is fixedly connected with the lower part; the upper end of the lower part or/and the lower end of the upper part are/is provided with a shear groove; the lower part is internally provided with a pre-embedded bracket when the lower part is poured, and the shearing-resistant and anti-pulling component is arranged at the upper end of the bracket. The invention can obviously improve the structural rigidity of the beam body, reduce the dead weight of the beam body, increase the spanning capability of the bridge, ensure the running stability of the high-speed railway, reduce the arrangement of prestressed reinforcement and further shorten the construction period; compared with the ultra-high performance concrete beam, the composite beam can greatly reduce the consumption of the ultra-high performance concrete.
Description
Technical Field
The invention relates to bridge engineering, in particular to a large-span superposed beam of a high-speed railway and a construction method thereof.
Background
At present, the high-speed rail operation mileage of China accounts for about 66.9% of the world high-speed rail operation mileage, China already has a high-speed rail network with the largest scale and the highest operation speed all over the world, and the railway construction of China continues to keep the high-level operation situation. Due to the terrain limitation, and the high-speed railway has high requirements on operation stability and comfort, the high-speed railway network line usually adopts a mode of replacing the road by a bridge, and takes prestressed concrete simply-supported beams with the spans of 24 m and 32m as main engineering carriers to construct the line. The high-speed railway bridge adopted at present is a common concrete reinforcement structure, and along with the development of high-speed railways in China, in order to meet the requirements of construction, operation and maintenance of a high-speed railway network, the span and the performance of the bridge need to meet higher requirements. The existing prestressed concrete beam of the high-speed railway has relatively low manufacturing cost, but has the problems of great self weight, large creep effect, easy cracking, poor durability and the like, so the spanning capability of the prestressed concrete beam is greatly limited, and the safety performance and the service life of the structure cannot meet the operation requirement of the high-speed railway.
Disclosure of Invention
The invention aims to provide a large-span superposed beam of a high-speed railway, which has high strength and good durability.
In order to achieve the purpose, the technical scheme adopted by the application is that the large-span superposed beam of the high-speed railway comprises an upper part and a lower part, wherein the upper part is formed by pouring concrete, the lower part is made of ultra-high performance concrete, the upper part is supported on the lower part, a shear-resistant anti-pulling member is arranged between the lower part and the upper part, the upper end of the shear-resistant anti-pulling member extends into the upper part and is fixedly connected with the upper part, and the lower end of the shear-resistant anti-pulling member extends into the lower part and; the upper end of the lower part or/and the lower end of the upper part are/is provided with a shear groove; the lower part is internally provided with a pre-embedded bracket when the lower part is poured, and the shearing-resistant and pulling-resistant member is arranged at the upper end of the bracket.
The UHPC has a series of advantages of high strength, good durability, excellent corrosion resistance and the like compared with the traditional concrete, but the manufacturing cost is far higher than that of the common concrete material, the upper part and the lower part of the UHPC are formed by pouring concrete, the upper part and the lower part are effectively connected by adopting the shear-resistant and anti-pulling component, and the performances of the two materials are fully utilized by the structure of the composite beam. The laminated beam adopts various measures to ensure the bonding integrity of the UHPC and the common concrete at the laminated surface, the shearing-resistant and pulling-resistant member is preset on the laminated surface, the shear groove is pre-pressed by a mould when the UHPC is poured, and the prestressed tendon with the proper through section is arranged according to the actual requirement to form the integral stress structure.
The arrangement form of the ultra-high performance concrete UHPC and the common concrete NC can fully utilize the compression resistance, the mechanical property and the crack resistance of the NC, so that the utilization rate of the material is maximized. Compared with a concrete beam structure, the invention can obviously improve the structural rigidity of the beam body, reduce the self weight of the beam body, increase the spanning capability of the bridge, ensure the running stability of the high-speed railway, reduce the arrangement of prestressed reinforcement and further shorten the construction period; compared with the ultra-high performance concrete beam, the composite beam can greatly reduce the consumption of the ultra-high performance concrete and reduce the manufacturing cost. Compared with the traditional concrete beam structure, the concrete beam structure has the advantages of large span, good durability, large rigidity and large bearing capacity, and the workload of later maintenance is also obviously reduced.
Furthermore, a first steel bar and a second steel bar which extend along the length direction of the lower part are arranged in the lower part; the first reinforcing steel bars are distributed on the periphery of the second reinforcing steel bars and serve as a stand for positioning and fixing the second reinforcing steel bars.
Furthermore, a first steel bar and a second steel bar which extend along the length direction of the lower part are arranged in the lower part; the first reinforcing steel bars and the second reinforcing steel bars are arranged at intervals along the width direction of the lower portion.
Further, the diameter of the second reinforcing bar is larger than the diameter of the first reinforcing bar.
Further, the second steel bar is a bent prestressed steel bar which is obliquely arranged.
The prestressed steel bar is tensioned to bear larger tensile stress, the stress of the auxiliary steel bar is generally smaller, and the diameter of the prestressed steel bar is more suitable than that of the first steel bar.
Through the setting of prestressing steel, reduced the arrangement of reinforcement volume, prestressing steel has arranged higher flexibility. Due to the high mechanical property of the UHPC, the arrangement of prestressed reinforcements can be greatly reduced, and the detailed construction is simplified; due to the high ductility of UHPC, the beam body in the structural form can be respectively arranged with prestressed steel bars in vivo and in vitro, so that the section size is reduced.
The prestressed steel bars of the external prestressed structure are arranged outside the column structure (namely the lower part), the prestressed steel bars are connected with the lower part only at limited steering points and anchoring positions, and the prestress is completely transferred to the structure by the anchorage device, so that the anchoring strength of the anchorage device is of great importance to the effectiveness of the prestress. The external prestress will cause the concrete in the anchorage device area to deform, so the external prestress has high requirement on the ductility of the material.
The inclination angle of the prestressed reinforcement is adjusted according to the actual situation.
The stress of the beam body is that the lower part structure is pulled and the upper part is pressed, and the compression resistance of the concrete is far higher than the tensile resistance, so the prestress gives the lower part structure a prepressing force to (partially) offset the self weight and the load to generate the pulling force when the actual stress is applied. But the bending moment of each section of the beam is different, the generated tensile stress is also different, and the section tensile stress of the support section is minimum. If there is a large pre-stress, there is a possibility that the roof will crack. Therefore, it is necessary to arrange a curved prestressed reinforcement according to the actual magnitude of the section bending moment. The construction method of the curve prestressed steel bars is post-tensioning, the prestressed steel bars penetrate into corrugated pipes pre-buried in the beam, namely, the steel bars are tensioned and anchored after pouring is finished, the corrugated pipes are filled by grouting, and after a certain strength is achieved, an anchoring structure is packaged, and anticorrosion measures are made.
Furthermore, a die is used for pre-extruding the shear notch when the UHPC is poured on the upper end surface of the lower part, and the upper surface is roughened after the UHPC is formed.
The upper part comprises a plate-shaped transverse part and a longitudinal part connected with the lower side of the transverse part, and the upper end of the lower part is connected with the longitudinal part through a shear-resistant and anti-drawing member; or the cross section of the upper part is T-shaped, the cross section of the lower part is inverted T-shaped, and the bottom end of the upper part is connected with the upper end of the lower part through a shearing-resistant and pulling-resistant member.
Further, the upper portion is of a plate-shaped structure, and the lower portion is provided with a U-shaped groove with an upward opening.
Furthermore, a groove with a downward opening is formed in the lower side of the upper portion, the upper end of the lower portion extends into the groove, and the outer side wall of the lower portion and the inner side wall of the groove are abutted to the upper portion through the anti-shearing and anti-drawing member, and the upper end face of the lower portion and the bottom face of the groove are abutted to the upper portion through the anti-shearing and anti-drawing member.
As another aspect of the invention, the invention also provides a construction method of the large-span superposed beam of the high-speed railway, which comprises the following operation steps:
s1, designing a superposed beam template and manufacturing a beam bottom template;
s2, binding a reinforcement cage after calculating the reinforcement allocation amount of the auxiliary reinforcement;
s3, fixing the shear-resistant anti-pulling member by taking the steel reinforcement cage as a vertical frame;
s4, fixing the prestressed corrugated pipe by taking the steel reinforcement cage as a vertical frame, and penetrating prestressed steel bars;
s5, manufacturing a side template of the beam, and completing die assembly;
s6, preparing and pouring ultra-high performance concrete, prepressing a shear notch on the upper surface, and curing at room temperature for 3 days; the greenhouse maintenance temperature can be 15-35 ℃;
s7, roughening the upper surface of the ultra-high performance concrete, infiltrating the concrete with clear water, and pouring the concrete;
s8, after concrete pouring is completed, maintaining at room temperature for 3 days, then removing the mold, watering and maintaining for 7 days, and then performing natural maintenance;
and S9, performing graded tension on the steel strand, grouting into the corrugated pipe after the completion of the grouting, and performing natural maintenance after maintenance measures of the leaked metal components are made.
The invention has the following beneficial effects:
1. the material utilization rate is high. The lower part of the composite beam structure is poured by UHPC, and the upper part of the composite beam structure is poured by NC, so that the good mechanical property and crack resistance of UHPC and the good compression resistance of NC can be fully exerted, the materials are fully utilized, and the economic benefit is better.
2. The construction period of the beam structure is shortened. Because the reinforcing bar quantity reduces, and the cross-sectional dimension reduces, and because UHPC is powdered concrete, but the constructability of complex construction reinforcing, the work progress of beam structure is simplified, the construction degree of difficulty reduces.
3. High strength bearing capacity, light structure dead weight and large span. The UHPC material used in the invention is a high-performance concrete material with high strength, high durability and high ductility, and the self weight of the UHPC structure under the same bearing capacity is 1/2-1/3 of that of an NC structure, so that the strength bearing capacity of the beam structure is greatly improved, and the spanning capacity of the beam structure is improved.
4. The durability is good, and the later maintenance workload is small. UHPC forResist againstThe invention has the advantages of greatly improving the durability of the beam structure, prolonging the service life of the structure and reducing the maintenance cost of later detection.
5. In the whole life cycle, the bridge structure adopting the composite beam has high rigidity. Compared with the common concrete beam structure, the invention can greatly improve the anti-cracking performance of the beam while reducing the deformation of the beam structure, effectively control the width of cracks, greatly improve the durability of the structure and reduce the later maintenance cost.
The invention is further described with reference to the following figures and detailed description. Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description. Or may be learned by practice of the invention.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to assist in understanding the invention, and are included to explain the invention and their equivalents and not limit it unduly. In the drawings:
fig. 1 is a schematic structural view of a large-span superposed beam of a high-speed railway for illustrating a first embodiment;
fig. 2 is a schematic structural view of a large-span superposed beam of a high-speed railway for explaining the second embodiment;
fig. 3 is a schematic structural view of a large-span superposed beam of a high-speed railway for explaining the third embodiment;
the labels in the figure are: the steel structure comprises a lower portion 1, a U-shaped groove 110, an upper portion 2, a shear-resistant and anti-pulling member 3, auxiliary steel bars 4, structural steel bars 410 and prestressed steel bars 5.
Detailed Description
The invention will be described more fully hereinafter with reference to the accompanying drawings. Those skilled in the art will be able to implement the invention based on these teachings. Before the present invention is described in detail with reference to the accompanying drawings, it is to be noted that:
the technical solutions and features provided in the present invention in the respective sections including the following description may be combined with each other without conflict.
Moreover, the embodiments of the present invention described in the following description are generally only examples of a part of the present invention, and not all examples. Therefore, all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative effort shall fall within the protection scope of the present invention.
With respect to terms and units in the present invention. The term "comprises" and any variations thereof in the description and claims of this invention and the related sections are intended to cover non-exclusive inclusions.
The first embodiment is as follows:
as shown in fig. 1, the large-span composite beam for a high-speed railway mainly comprises Ultra High Performance Concrete (UHPC), common concrete (NC), auxiliary reinforcing steel bars, prestressed reinforcing steel bars 5 and a related shear-resistant structure; wherein: the lower part 1 of the beam body is formed by pouring UHPC, the upper part 2 of the beam body is formed by pouring NC, the upper part 2 is supported on the lower part 1, a shearing-resistant and pulling-resistant member 3 is arranged between the lower part 1 and the upper part 2, the upper end of the shearing-resistant and pulling-resistant member 3 extends into the upper part 2 and is fixedly connected with the upper part 2, and the lower end of the shearing-resistant and pulling-resistant member extends into the lower part 1 and is fixedly connected with the lower part 1. The auxiliary steel bars 4 mainly include horizontal and longitudinal auxiliary steel bars, local reinforcing steel bars, stirrups, structural steel bars 410 and the like, and the prestressed steel bars 5 are tensioned by a post-tensioning method. And (3) tensioning and anchoring the prestressed reinforcement 5 after the beam concrete is poured and reaches a certain strength, and grouting the corrugated pipe. The auxiliary reinforcing steel bars can prevent the beam body from cracking caused by uneven shrinkage of concrete, the local reinforcing steel bars are used for resisting overlarge local stress to the concrete, the stirrups, the bent prestressed tendons and the concrete bear load shearing force together, and the construction reinforcing steel bars 410 are used for supporting the stirrups, positioning and fixing the prestressed reinforcement 5.
The upper part 2 of the present embodiment is T-shaped in cross section, i.e. it is mainly composed of a transverse part arranged transversely and an upper part of a web, which is connected with the upper end of the lower part 1 by a shear resistant anti-drawing member 3. The lower part 1 is the lower end of a web plate of a T-shaped cross-section beam, and the lower part 1 is arranged into a horseshoe shape with a larger area in order to arrange a prestressed reinforcement 5 and a common reinforcement 4 conveniently.
The beam body is internally provided with common steel bars 4 distributed along the longitudinal direction or the cross section, and the lower part 1 is internally provided with prestressed steel bars 5 extending in a curve along the length direction of the lower part 1. Before the UHPC is poured, the ordinary steel bars 4 are vertical frames fixed with prestressed steel bars 5. The prestressing tendons 5 are here arranged in a curved manner in the longitudinal direction, mainly according to the beam section bending moment.
By arranging the prestressed reinforcement 5, the using amount of the common reinforcement 4 is reduced, the bearing capacity of the normal section and the shear resistance of the oblique section of the T-shaped beam are improved, and the upper span limit of the T-shaped beam is improved.
The lower part 1 is internally provided with an auxiliary steel bar 4 and a prestressed steel bar 5 which extend along the length direction of the lower part 1; here, the auxiliary reinforcing bars 4 are distributed around the prestressed reinforcing bars 5. The diameter of the prestressed reinforcement 5 is larger than that of the auxiliary reinforcement 4. Here the prestressing tendons 5 are arranged obliquely.
Through the setting of prestressing steel 5, reduced the arrangement of reinforcement volume, prestressing steel 5 has arranged higher flexibility. Due to the high mechanical property of the UHPC, the arrangement of the prestressed reinforcement 5 can be greatly reduced, and the detailed structure is simplified; due to the high ductility of UHPC, the beam in this structural form can be provided with prestressed reinforcements 5 inside and outside the body, respectively, reducing the cross-sectional dimensions.
The shear-resistant and anti-drawing member may be screw rod, screw rod or other member with outer thread, bent steel bar or other member, and during casting UHPC, the member is partially pre-buried in the lower part of the member and the other part of the member is buried in post-cast concrete, i.e. the upper part of the member.
The structural section of the large-span superposed beam of the high-speed railway can be in various forms such as an I-shaped beam, a box beam and the like besides a T-shaped beam, the section of the corresponding lower part is in a horseshoe shape or an inverted T shape or a U groove shape, and the section of the upper part is in a T shape or a plate shape. The following second to third embodiments are other arrangements of the long-span composite beam for high-speed railways, but the present long-span composite beam for high-speed railways is not limited to the following arrangements.
Example two:
referring to fig. 2, unlike the first embodiment, the cross section of the upper part 2 is T-shaped, and the cross section of the lower part 1 is inverted T-shaped, so that the cross section of the composite beam is formed into an I-shape. Compared with the first embodiment, the second embodiment has the advantages that the area of the lower part 1 is larger, prestressed reinforcements and common reinforcements can be arranged more conveniently, and therefore the bearing capacity of the second embodiment is larger than that of the first embodiment. In contrast, in the second embodiment, when a reinforcement cage is bound and a template is built, the construction process is more complex, and the UHPC consumption is more, so the engineering cost of the second embodiment is higher.
Example three:
as shown in fig. 3, unlike the first and second embodiments, the upper part 2 is a plate-like structure, and the lower part 1 is provided with a U-shaped groove 110 which is opened upward. The upper part 2 and the lower part 1 form a box girder structure. A prestressed steel bar 5 and a common steel bar 4 which extend along the length direction of the lower part 1 are arranged in the lower part 1; the prestressed reinforcement 5 and the ordinary reinforcement 4 of this embodiment are arranged at intervals in the width direction of the lower portion 1. Wherein the horizontal part of lower part 1 is the prestressing steel of bottom plate and arranges along the vertical full length straight line, and the vertical part is the prestressing steel of two webs and arranges the curve according to the size of every section moment of flexure. The cross-sectional area of the lower part 1 of the third embodiment is far larger than that of the first and second embodiments, and the arrangement of the prestressed reinforcements is more flexible, so that the spanning capability and the beam width of the third embodiment are larger than those of the first and second embodiments, and the third embodiment is more suitable for a multi-line large-span railway bridge. Furthermore, in order to reduce the consumption of building materials and the self weight of the structure, the section of the box girder can be designed to be a variable section along the longitudinal direction, namely, the height of the web plate of the lower part 1 can be properly reduced along the longitudinal direction according to the actual bending moment of the section.
The large-span superposed beam of the high-speed railway enables the UHPC with better mechanical property and crack resistance to be positioned in a tension area and the NC with better compression resistance to be positioned in a compression area, greatly improves the material utilization rate and optimizes the structural performance of the beam. The shear-resistant and anti-pulling member 3 can adopt various forms such as a screw rod, a threaded rod, a bent reinforcing steel bar and the like besides the preferable structure, and the arrangement form is arranged by adopting a proper interval according to the requirements of shear resistance and anti-pulling at the overlapping surface of the actual beam structure.
The sizes of each component of the laminated beam, including the section size, the height of UHPC, the position of the laminated surface and the like, the reinforcing bar index and the prestress ratio of the laminated beam can be determined according to the specific situation in the actual engineering.
The construction method comprises the specific steps of ① designing a laminated beam template and manufacturing a beam bottom template, ② calculating auxiliary reinforcement amount and then binding a reinforcement cage, ③ fixing a shear-resistant and pull-resistant component by taking the reinforcement cage as a vertical frame, ④ fixing a prestressed corrugated pipe by taking the reinforcement cage as the vertical frame and penetrating prestressed reinforcements, ⑤ manufacturing a side template of the beam to complete mold closing, ⑥ preparing and pouring ultrahigh-performance concrete (UHPC), prepressing a shear notch on the upper surface of the ultrahigh-performance concrete, performing room-temperature curing for 3 days, roughening the upper surface of ⑦ ultrahigh-performance concrete, pouring concrete after soaking with clear water, removing a mold after 3-day room-temperature curing after ⑧ concrete pouring is completed, performing natural curing after watering and curing for 7 days, and ⑨ grading and tensioning steel strands, grouting in the corrugated pipe after finishing grouting, and performing maintenance measures on metal components which leak outwards, and then performing natural curing.
The arrangement form of the UHPC and the NC can fully utilize the compression resistance of the NC, the mechanical property and the crack resistance of the UHPC, so that the utilization rate of the material is maximized. Compared with a concrete beam structure, the invention can obviously improve the structural rigidity of the beam body, reduce the self weight of the beam body, increase the spanning capability of the bridge, ensure the running stability of the high-speed railway, and reduce the arrangement of the prestressed reinforcement 5, thereby shortening the construction period; compared with the ultra-high performance concrete beam, the composite beam can greatly reduce the consumption of the ultra-high performance concrete and reduce the manufacturing cost.
As further explanation of the invention, the cross section form of the beam structure has various forms (T beam, box beam, pi beam, I beam and the like), and a proper cross section form is designed according to actual construction and operation requirements; the superposed surface is positioned near the neutral axis of the section, and the position of the superposed surface is determined according to actual stress so as to ensure the optimal combination of material performance.
In the implementation process, in order to simplify the construction process and simultaneously ensure the performance of the beam structure, tension exists in the upper part 1 of the hogging moment area of the continuous beam, if the tension is large, the UHPC can be considered to be used for pouring the section completely, if the tension is small, the laminated beam structure is still adopted, prestressed reinforcements 5 are calculated and arranged according to the stress condition, the width of a crack is controlled, and the working performance of common concrete in the tension area is ensured.
The beam body, namely the upper part 2 and the lower part 1 can be prefabricated under good conditions in a factory, and starting from engineering requirements of light weight, few joints and rapid construction, steel fibers in a UHPC structure are prevented from agglomerating, the continuity of the steel fibers is ensured, the maintenance conditions of the UHPC structure are ensured, and the beam structure can reach the expected service state.
The high ductility characteristic of UHPC material pair is considered, the arrangement of the prestressed reinforcement 5 and the auxiliary reinforcement 4 has higher flexibility, the reinforcement arrangement can be simplified according to actual requirements, so that the construction is simplified, and the section size can also be reduced by arranging the prestressed reinforcement in vivo or in vitro.
The contents of the present invention have been explained above. Those skilled in the art will be able to implement the invention based on these teachings. All other embodiments, which can be derived by a person skilled in the art from the above description without inventive step, shall fall within the scope of protection of the present invention.
Claims (10)
1. The large-span superposed beam of the high-speed railway is characterized by comprising an upper part and a lower part made of ultra-high performance concrete, wherein the upper part is supported on the lower part, a shear-resistant and anti-pulling member is arranged between the lower part and the upper part, the upper end of the shear-resistant and anti-pulling member extends into the upper part and is fixedly connected with the upper part, and the lower end of the shear-resistant and anti-pulling member extends into the lower part and is fixedly connected with the lower part; the upper end of the lower part or/and the lower end of the upper part are/is provided with a shear groove; the lower part is internally provided with a pre-embedded bracket when the lower part is poured, and the shearing-resistant and pulling-resistant member is arranged at the upper end of the bracket.
2. The large-span superposed beam of the high-speed railway according to claim 1, wherein a first reinforcing steel bar and a second reinforcing steel bar extending along the length direction of the lower part are arranged in the lower part; the first reinforcing steel bars are distributed on the periphery of the second reinforcing steel bars and serve as a stand for positioning and fixing the second reinforcing steel bars.
3. The large-span superposed beam of the high-speed railway according to claim 1, wherein a first reinforcing steel bar and a second reinforcing steel bar extending along the length direction of the lower part are arranged in the lower part; the first reinforcing steel bars and the second reinforcing steel bars are arranged at intervals along the width direction of the lower portion.
4. The large-span composite beam for the high-speed railway according to claim 2 or 3, wherein the diameter of the second reinforcing steel bar is larger than that of the first reinforcing steel bar.
5. The large-span composite beam for the high-speed railway according to claim 2 or 3, wherein the second reinforcing steel bars are obliquely arranged and bent prestressed reinforcing steel bars.
6. The large-span composite beam for high-speed railways according to claim 1, wherein the lower upper end surface is a roughened surface.
7. The large-span superposed beam of the high-speed railway according to claim 1, wherein the upper part comprises a plate-shaped transverse part and a longitudinal part connected with the lower side of the transverse part, and the upper end of the lower part is connected with the longitudinal part through a shear-resistant and anti-pulling member; or the cross section of the upper part is T-shaped, the cross section of the lower part is inverted T-shaped, and the bottom end of the upper part is connected with the upper end of the lower part through a shearing-resistant and pulling-resistant member.
8. The large-span superposed beam of the high-speed railway according to claim 1, wherein the upper part is a plate-shaped structure, and the lower part is provided with a U-shaped groove with an upward opening.
9. The large-span composite beam for the high-speed railway according to claim 8, wherein the lower side of the upper part is provided with a groove with a downward opening, the upper end of the lower part extends into the groove, and the outer side wall of the lower part is abutted with the inner side wall of the groove, and the upper end surface of the lower part is abutted with the bottom surface of the groove through the shear-resistant and anti-pulling member.
10. The construction method of the large-span superposed beam of the high-speed railway is characterized by comprising the following operation steps of:
s1, designing a superposed beam template and manufacturing a beam bottom template;
s2, binding a reinforcement cage after calculating the reinforcement allocation amount of the auxiliary reinforcement;
s3, fixing the shear-resistant anti-pulling member by taking the steel reinforcement cage as a vertical frame;
s4, fixing the prestressed corrugated pipe by taking the steel reinforcement cage as a vertical frame, and penetrating prestressed steel bars;
s5, manufacturing a side template of the beam, and completing die assembly;
s6, preparing and pouring ultra-high performance concrete, prepressing a shear notch on the upper surface, and curing at room temperature for 3 days;
s7, roughening the upper surface of the ultra-high performance concrete, infiltrating the concrete with clear water, and pouring the concrete;
s8, after concrete pouring is completed, maintaining at room temperature for 3 days, then removing the mold, watering and maintaining for 7 days, and then performing natural maintenance;
and S9, performing graded tension on the steel strand, grouting into the corrugated pipe after the completion of the grouting, and performing natural maintenance after maintenance measures of the leaked metal components are made.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113175155A (en) * | 2021-04-27 | 2021-07-27 | 华中科技大学 | Ultra-high performance concrete T-shaped beam of FRP (fiber reinforced plastic) prestressed system and preparation method thereof |
| CN114474337A (en) * | 2022-01-05 | 2022-05-13 | 中铁八局集团第七工程有限公司 | Rapid prefabrication and maintenance method for railway T beam in alpine and high-altitude area |
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