Novel nesting structure applied to transverse connection cast-in-place section of UHPC-NC composite T beam

Abstract

The invention discloses a nested structure applied to a transverse connection cast-in-place section of a UHPC-NC laminated T-beam, which comprises a reinforced concrete T-beam, an ultra-high performance concrete reinforcing thin layer, nested channel steel, studs and connecting straight bars, and can also provide a steel bar frame foundation for the cast-in-place section. In addition, the invention further relates to an assembling and overlapping method of the ultra-high-performance concrete-common concrete overlapping bridge deck structure, which comprises the following steps of: after prefabricating the T-shaped beam in a factory, performing corresponding interface treatment on the surface on a construction site, punching to reserve holes conforming to the sizes of the studs, and then pouring the ultra-high-performance concrete thin layer to form the ultra-high-performance concrete-common concrete overlapping bridge deck structure. And meanwhile, reserving of holes is paid attention to during pouring of the UHPC thin layer, and the nesting structure prefabricated in a factory is mounted before pouring of the cast-in-place section between the beams in a project. The construction condition is simple, the construction speed is high, the high tensile toughness of materials can be brought into full play, the anti-cracking performance of the bridge deck in the hogging moment area is effectively improved, the bonding anti-sliding effect of the common concrete layer and the ultra-high performance concrete thin layer is effectively enhanced, the foundation of a steel bar system of a cast-in-place section can be formed, and the working procedures are effectively reduced.

Description

Technical Field

[0001] The invention relates to a novel nested structure applied to a UHPC-NC composite T-beam transversely connected cast-in-place section. Background Art

[0002] With the development of the economy, the application of bridges has grown rapidly. However, a large number of bridges built in the early days showed that in the negative bending moment area of ​​the bridge deck, bridge deck cracking caused by concrete tension occurred frequently. Under the long-term effects of load and adverse environment, the bridge deck steel bars were severely corroded, affecting the safety and durability of the bridge.

[0003] At present, the more commonly used means of crack resistance is to apply prestress to the concrete bridge deck in the negative bending zone. The traditional method is to pre-lift the middle support of the bridge, and then drop the support to generate prestress after the concrete hardens, or to apply steel beam prestress in the negative bending zone to achieve bridge deck prestress. However, the bridge support top-down process is complicated and the construction period is long, and most of the prestress applied by steel beams will be transferred. Under the long-term action of concrete shrinkage creep, the actual prestress rate of the bridge deck is usually less than 60%, and the layout of steel beams also makes it difficult to partially renovate the bridge deck in the later stage. Therefore, in recent years, more and more projects have used UHPC thin layers to replace the surface layer of ordinary concrete in the negative bending zone to form UHPC-NC composite bridge decks. UHPC is a sustainable development material with ultra-high strength, ultra-durability, and in line with the country. Because it contains steel fibers and active components, its tensile toughness and resistance to adverse environmental erosion are better than ordinary concrete. Therefore, the composite slab is composed of a UHPC thin layer and an ordinary concrete layer. This not only reduces the material consumption and keeps the cost controllable, but also delays cracking because the ordinary concrete base is close to the plastic neutral axis of the composite beam. The UHPC surface layer is located in the most unfavorable tensile zone, which can give full play to the high tensile toughness of the material, improve the crack resistance of the bridge deck and enhance the overall durability.

[0004] However, the bonding strength and anti-slip performance between UHPC and ordinary concrete are the key to the long-term functioning of this composite slab. Therefore, the new nested structure designed by the present invention can effectively improve the ability of the composite slab to function together for a long time, and together with the cast-in-place concrete, play the role of horizontally connecting adjacent T-beams. Summary of the invention

[0005] The present invention aims to overcome the defects in the prior art by targeting the property problems caused by different reinforcement interface methods, and provides a bridge deck structure reinforced with ultra-high performance concrete and a reinforcement method thereof. An ultra-high performance concrete thin layer is used to replace the ordinary concrete surface layer in the negative bending moment zone to form an ultra-high performance concrete-ordinary concrete composite bridge deck, thereby improving the crack resistance of the bridge deck and enhancing the overall durability. In order to realize the function of different interfaces working together, the present invention proposes a new nested structure applied to the transverse connection cast-in-place section of the UHPC-NC composite T-beam.

[0006] The present invention is achieved through the following technical solutions:

[0007] A composite beam reinforced with grooved UHPC, including precast concrete T-beam, UHPC thin layer, precast nested channel steel, bolts, straight reinforcement, by cutting a rectangular groove in the concrete slab surface and roughening the concrete slab surface, and then pouring the UHPC thin layer. The concrete T-beam has ordinary steel bars built in, which will be linked with the connecting straight reinforcement to form a system.

[0008] As a preferred solution, the UHPC reinforcement layer is specifically of RPC120 strength grade in the "Reactive Powder Concrete" (GB / T 31387-2015) specification.

[0009] As a preferred solution, the rectangular groove on the concrete slab surface improves the strength and bearing capacity of the composite beam and the anti-slip performance of the interface between the concrete slab and the UHPC reinforcement layer.

[0010] As a preferred solution, most of the components are prefabricated in a factory, saving on-site construction procedures and construction time.

[0011] The implementation of the present invention has the following beneficial effects:

[0012] 1. High bearing capacity, good crack resistance and good mechanical properties.

[0013] 2. The construction is simple, the on-site construction period is short, and the construction cost is controllable.

[0014] 3. The bonding between the UHPC reinforcement layer and the ordinary concrete slab is ensured, and the reliability of the horizontal connection cast-in-place section is enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is an overall three-dimensional model diagram of the novel nested structure of the present invention.

[0016] Figure 2 This is a composition diagram of the novel nested structure of the present invention.

[0017] Figure 3 Schematic diagram of the bolts and straight bars of the novel nested structure of the present invention. DETAILED DESCRIPTION

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be further described below with reference to the accompanying drawings.

[0019] like Figure 1-3As shown, a new nested structure applied to the transverse connection cast-in-place section of the UHPC-NC composite T-beam includes a precast concrete T-beam 1, a UHPC thin layer 2, a precast nested channel steel 3, studs 4, studs 5, and straight bars 6, wherein the studs 4 and 5 correspond to the reserved hole sizes of the precast nested channel steel 3, and ordinary steel bars are built into the concrete T-beam, which will be interlocked with the connecting straight bars to form a system.

[0020] The UHPC thin layer 2 is specifically of RPC120 strength grade in the "Reactive Powder Concrete" (GB / T 31387-2015) specification.

[0021] The UHPC thin layer 2 is poured after the rectangular groove is chiseled and the roughening process is completed on the concrete T-beam 1, and the UHPC thin layer 2 is completely joined to the concrete T-beam 1 through the reserved holes.

[0022] The UHPC thin layer 2 is located on the concrete T-beam 1, and the studs 4, 5, straight bars 6 and prefabricated nested channel steels form a nested structure, which firmly nests the UHPC thin layer and ordinary concrete to achieve the function together.

[0023] Among them, the built-in steel bars of ordinary concrete T-beams and the connecting straight bars of the nested structure together form a steel bar system.

[0024] It should be noted that the present invention is a new type of nested structure applied to the transverse connection of the cast-in-place section of the UHPC-NC composite T-beam. When applied to bridge engineering, different internal structural parameters are used in different projects. The size of the concrete T-beam 1, the thickness of the UHPC thin layer 2, the steel fiber content, the diameter of the ordinary steel bars built into the T-beam, and the connecting straight bars can be determined according to the specific project.

[0025] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A new nested structure used for the transverse connection of the cast-in-place section of the UHPC-NC composite T-beam, comprising a precast concrete T-beam 1, a UHPC thin layer 2, a precast nested channel steel 3, a stud 4, a stud 5, and a straight reinforcement 6, wherein the studs 4 and 5 correspond to the reserved hole sizes of the precast nested channel steel 3, and ordinary steel bars are built into the concrete T-beam, which will be interlocked with the connecting straight reinforcement to form a system.

2. According to claim 1, a novel nested structure applied to the transverse connection of the cast-in-place section of the UHPC reinforced T-beam is characterized by: The UHPC thin layer 2 is on the concrete T-beam 1, and the studs 4, 5, straight bars 6 and the nested steel channels 3 form a nested structure.

3. According to claim 1, a novel nested structure applied to the transverse connection of the cast-in-place section of the UHPC reinforced T-beam is characterized by: After the interface of concrete T-beam 1 is well treated, the rectangular groove is chiseled and the roughening process is completed, the UHPC reinforcement layer 3 is poured. At the same time, it is necessary to align the reserved holes of the concrete T-beam with the holes of the UHPC thin layer 2, so that the nested structure is completely connected with the composite T-beam.

4. According to claim 1, a novel nested structure applied to the transverse connection of the cast-in-place section of the UHPC-NC composite T-beam is characterized by: The concrete T-beam 1 is specifically of the C50 strength grade in the Code for Design of Concrete Structures (GB 50010-2010).

5. According to claim 1, a novel nested structure applied to the transverse connection of the cast-in-place section of the UHPC-NC composite T-beam is characterized by: The UHPC thin layer 2 is specifically of RPC120 strength grade in the "Reactive Powder Concrete" (GB / T 31387-2015) specification.

6. The novel nested structure applied to the transverse connection of the cast-in-place section of the UHPC-NC composite T-beam according to claim 1 is characterized by: Concrete T-beam 1 internal reinforcement and connecting straight reinforcement 6 reinforcement system.

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