Anti-pulling and non-shearing prefabricated composite beam in hogging moment area and construction method of anti-pulling and non-shearing prefabricated composite beam

Abstract

The invention provides a hogging moment area anti-pulling non-shearing prefabricated composite beam and a construction method thereof.The prefabricated beam section is used for a continuous beam bridge hogging moment area, sliding and pulling resistance of a main beam and a concrete plate are achieved through a sliding module, and the prefabricated beam section comprises a steel beam, a prefabricated concrete plate and the sliding module; the sliding module is composed of a T-shaped connecting piece and a T-shaped rail groove. In a hogging moment area of the steel-concrete continuous composite beam bridge, the composite beam can release constraint between the concrete plate and the steel beam through bidirectional sliding, large tensile stress generated by cooperative deformation of the concrete plate and the steel beam is avoided, the longitudinal prestress introduction degree of the concrete plate is improved, and the long-term performance and durability of the concrete plate are effectively improved; and the concrete slab has an anti-pulling effect and can be prevented from being separated from the steel beam. Meanwhile, the composite beam is prefabricated in a factory, standardized production can be achieved, splicing is conducted on a construction site according to actual requirements, the structure is simple, construction is rapid, stress is reasonable, and good technical and economic benefits are achieved.

Description

Technical Field

[0001] The invention relates to a prefabricated bridge structure, belonging to the technical field of bridge structures, and in particular to a prefabricated composite beam that resists pullout but not shearing in a negative moment zone and a construction method thereof. Background Art

[0002] Steel-concrete composite structures generally use shear connectors to connect steel beams and concrete slabs to form a whole for coordinated force. Under the action of positive bending moment, the concrete slab is in a compressive state and the steel beam is in a tensile state, which fully utilizes the mechanical properties of both and improves the rigidity and bearing capacity of the structure. However, in a large-span continuous system, the composite beam section near the support is subject to negative bending moment, and the concrete slab will produce large tensile stress under the action of negative bending moment, causing cracking, affecting the durability of the structure.

[0003] There are two main methods to solve the problem of concrete slab cracking in negative bending moment areas: one is to apply prestress in the concrete slab, and offset or reduce the tensile stress generated by the concrete slab during service by pre-stressing the concrete. However, since the shear connector connects the concrete slab and the steel beam to form a whole, a large part of the prestress is borne by the steel beam, and the prestress introduction degree is low; the other method is to apply pull-out but not shear-resistant technology, which allows the concrete slab and the steel beam to have relative movement under the action of negative bending moment, reducing the tensile stress of the concrete slab caused by the deformation of the steel beam, and the prestress can all act on the concrete slab, with a high prestress introduction degree and better effect.

[0004] The current pull-out-resistant but not shear-resistant technology mainly adopts shear connectors made of low elastic modulus materials, all of which require on-site concrete pouring and are complicated to construct. Therefore, it is urgent to invent a prefabricated composite beam that is simple to construct, can meet standardized production and prefabricated construction, and is not easy to crack under the action of negative bending moment, so as to be used in the negative bending moment area of ​​the continuous beam bridge and improve the durability of the continuous composite beam. Summary of the invention

[0005] In order to solve the problems of the prior art, the present invention provides a prefabricated composite beam that is pull-out resistant but not shear resistant in a negative bending moment zone and a construction method thereof. The steel beam and the concrete slab are assembled into a whole through a sliding module to achieve sliding and pull-out resistance between the two.

[0006] The present invention provides a prefabricated composite beam that is pull-out resistant but not shear resistant in a negative moment zone, comprising a steel main beam, a cross beam, a concrete bridge deck, a sliding module and a lifting ring, wherein a plurality of steel main beams are connected to form a steel beam frame through a plurality of cross beams. The sliding module comprises a T-shaped connector and a T-shaped track groove, wherein the T-shaped connector is welded to the steel main beam, the T-shaped track groove is anchored to the concrete bridge deck, the T-shaped connector and the T-shaped track groove are matched and connected in a one-to-one correspondence, and the steel main beam slides along the T-shaped track groove through the T-shaped connector.

[0007] Lifting rings are welded at both ends of the steel beam frame.

[0008] The T-shaped connectors are uniformly welded at the center line of the upper flange of the steel beam at a certain interval.

[0009] The present invention also provides a construction method for a prefabricated composite beam that is tension-resistant but not shear-resistant in a negative bending moment zone, comprising the following steps: S1: Prefabricate steel beams and T-shaped connectors in the factory, and weld the T-shaped connectors evenly at the center line of the upper flange of the steel beam at a certain interval; S2: The T-shaped track groove is prefabricated in the factory, and the T-shaped track groove is assembled with the already welded T-shaped connector, and sealing plates are welded at both ends of the T-shaped track groove; S3: Welding cross beams between each steel main beam to form a steel beam frame; S4: Factory prefabricated concrete slab, integrally cast the T-shaped track groove of the sliding module and the bridge deck reinforcement; S5: Weld lifting rings at both ends of the prefabricated composite beam to facilitate the lifting of the prefabricated beam section, and serve as shear connectors when the prefabricated bridge deck is wet-jointed and cast on site later.

[0010] In step S2, lubricating paint is evenly applied to the outer surface of the T-shaped connector and the inside of the T-shaped track groove before assembly.

[0011] In step S4, before pouring concrete, the T-shaped track groove is welded to the structural steel bars of the precast concrete slab, and the lower edge of the web of the T-shaped track groove is ensured to be flush with the lower edge of the precast concrete slab.

[0012] After the assembly is completed in step S5, the prefabricated composite beams resistant to pull-out but not resistant to shear in the negative moment zone are transported to the construction site in the form of integral composite beam sections and installed in the negative moment zone of the continuous beam bridge.

[0013] The beneficial effects of the present invention are: (1) The pull-out resistant but non-shear resistant connector of the present invention has a high longitudinal sliding freedom while ensuring vertical pull-out resistance, which can effectively reduce the tensile stress of the concrete slab caused by the deformation of the steel beam, enhance the effect of applying prestress to the bridge deck, and effectively improve the crack resistance of the composite beam.

[0014] (2) The sliding module of the present invention uses a T-shaped connector with a shorter longitudinal length. When the beam undergoes a large bending deformation, the T-shaped track groove will also produce bending moment deformation. Since the T-shaped connector is short in length, it will not get stuck.

[0015] (3) When the sliding module of the present invention resists pull-out, stress concentration does not occur in conventional shear connectors. The pull-out force of the T-shaped connector is first transmitted to the T-shaped track groove, and then evenly transmitted to the interior of the concrete slab through the T-shaped track groove, thereby avoiding the generation of concentrated pull-out force in the concrete slab and improving the pull-out resistance of the connector.

[0016] (4) The sliding modules of the present invention are arranged in sections, unlike the PBL connectors which are arranged throughout the entire length, and thus will not cause longitudinal splitting of the concrete bridge deck.

[0017] (5) The present invention can determine the length of the prefabricated composite beam according to the actual length requirement of the negative moment zone of the bridge. The sliding module is used in the prefabricated composite beam to achieve pull-out resistance but not shear resistance; at the end of the prefabricated composite beam, the lifting ring above the beam is used as a shear connector, and the beam is used as a wet joint template. The wet joint is cast above the beam, ending the pull-out resistance but not shear resistance zone and transitioning to the combined stress state of the bridge deck and steel beam in the positive moment zone.

[0018] (6) The pull-out resistant but not shear resistant connector of the present invention is adaptable to different main beam forms, and the size and quantity of the prefabricated components can also be selected according to the load level and bridge layout.

[0019] (7) All components of the pull-out resistant but not shear resistant prefabricated composite beam of the present invention are prefabricated and assembled in the factory. The cross beam and the steel main beam form a steel beam frame with good integrity and convenient lifting and installation. Compared with the traditional on-site connection of plate beams, the construction is more convenient and faster, which meets the prefabrication and standardization requirements of assembled bridges. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the pull-out resistant but not shear resistant prefabricated composite beam component of the present invention.

[0022] Figure 2 This is a cross-sectional view of the pull-out resistant but not shear resistant prefabricated composite beam of the present invention.

[0023] Figure 3 It is a schematic diagram of assembling the sliding module of the present invention.

[0024] Figure 4 It is a cross-sectional view of the precast concrete panel of the present invention.

[0025] Figure 5 This is a schematic diagram of the completed assembly of the pull-out resistant but not shear resistant prefabricated composite beam of the present invention.

[0026] Marked in the figure are: 1. Steel main beam; 2. Precast concrete slab; 3. T-shaped connector; 4. T-shaped track groove; 5. Cross beam; 6. Lifting ring. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The present invention provides a prefabricated composite beam that is tension-resistant but not shear-resistant in a negative moment zone, such as Figure 1 and Figure 5 As shown, it mainly includes a steel main beam 1, a precast concrete slab 2, a T-shaped connecting piece 3, a T-shaped track groove 4, and a cross beam 5.

[0029] like Figure 2 As shown, the steel main beam 1 and the precast concrete slab 2 can be assembled together through a T-shaped connector 3 and a T-shaped track groove 4. Two or more T-shaped connectors 3 and a T-shaped track groove 4 form a sliding module, and the two can slide relative to each other. Figure 3 As shown. The T-shaped connector 3 is welded to the steel main beam 1, and the T-shaped track groove 4 is cast in the precast concrete slab 2, as shown in FIG. Figure 4 As shown, when subjected to negative bending moment, the steel main beam 1 and the precast concrete slab 2 can produce relative movement in the longitudinal direction of the bridge, thereby reducing the tensile stress of the precast concrete slab 2 caused by the bending deformation of the steel main beam 1.

[0030] The construction process of the present invention is: 1) The steel main beam 1 and the T-shaped connector 3 are prefabricated in the factory, and the T-shaped connector 3 is evenly welded at the center line of the upper flange of the steel beam 1 at a certain interval.

[0031] 2) The T-shaped track groove 4 is prefabricated in the factory, and the T-shaped track groove 4 is assembled with the already welded T-shaped connector 3, such as Figure 3 As shown, sealing plates are welded at both ends of the T-shaped track groove 4.

[0032] 3) Cross beams 5 are welded to the ends of each prefabricated steel main beam 1 to form a steel beam frame.

[0033] 4) The concrete slab 2 is cast in the factory. Before casting the concrete, the T-shaped track groove 4 is welded to the structural steel bars of the precast concrete slab 2, and the lower edge of the web of the T-shaped track groove 4 is ensured to be flush with the lower edge of the precast concrete slab 2. Figure 4 shown.

[0034] 5) Weld lifting rings 6 at the upper flange positions of the main beams corresponding to the cross beams at both ends of the composite beam to facilitate the overall lifting of the prefabricated beam section.

[0035] 6) During on-site installation, the precast bridge deck is connected to the bridge decks of other beam sections through wet joints. When pouring the wet joints, concrete is poured above the beam 5 at the end of the precast panel. The beam 5 serves as the bottom formwork of the wet joint and the lifting ring 6 serves as the shear connector.

[0036] The prefabricated composite beams resistant to pull-out but not shear in the negative moment zone described in this embodiment can select the size and quantity of components according to different bridge widths and different load levels, prefabricate various assembly components in advance, and transport them to the construction site as a whole after assembly. They can be quickly connected with other beam sections to form a bridge. The prefabricated composite beams resistant to pull-out but not shear in the negative moment zone described in the present invention have standardized production steps, which simplifies the design and construction process while effectively solving the problem of concrete slab cracking in the negative moment zone, and meets the prefabrication and standardization requirements of prefabricated bridges.

[0037] The embodiments described in this specification are only specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention, without departing from the principle of the present invention, should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A prefabricated composite beam that is tension-resistant but not shear-resistant in a negative moment zone, comprising a steel main beam, a cross beam, a concrete bridge deck, a sliding module and a hanging ring, wherein a plurality of steel main beams are connected by a plurality of cross beams to form a steel beam frame, characterized in that: The sliding module includes a T-shaped connector and a T-shaped track groove. The T-shaped connector is welded to the steel main beam, and the T-shaped track groove is anchored to the concrete bridge deck. The T-shaped connector and the T-shaped track groove are connected in a one-to-one corresponding manner, and the steel main beam slides along the T-shaped track groove through the T-shaped connector.

2. The prefabricated composite beam resistant to pull-out but not shear in negative moment zone according to claim 1, characterized in that: Lifting rings are welded at both ends of the steel beam frame.

3. The prefabricated composite beam resistant to pull-out but not shear in negative moment zone according to claim 1, characterized in that: The T-shaped connectors are uniformly welded at the center line of the upper flange of the steel beam at a certain interval.

4. A construction method for a prefabricated composite beam that is tension-resistant but not shear-resistant in a negative bending moment zone, characterized in that: The following steps are involved: S1: Prefabricate steel beams and T-shaped connectors in the factory, and weld the T-shaped connectors evenly at the center line of the upper flange of the steel beam at a certain interval; S2: The T-shaped track groove is prefabricated in the factory, and the T-shaped track groove is assembled with the already welded T-shaped connector, and sealing plates are welded at both ends of the T-shaped track groove; S3: Welding cross beams between each steel main beam to form a steel beam frame; S4: Factory prefabricated concrete slab, integrally cast the T-shaped track groove of the sliding module and the bridge deck reinforcement; S5: Weld lifting rings at both ends of the prefabricated composite beam to complete the assembly.

5. The construction method of a prefabricated composite beam resistant to pull-out but not resistant to shear in negative bending moment area according to claim 4, characterized in that: In step S2, lubricating paint is evenly applied to the outer surface of the T-shaped connector and the inside of the T-shaped track groove before assembly.

6. The construction method of a prefabricated composite beam resistant to pull-out but not resistant to shear in a negative moment zone according to claim 4, characterized in that: In step S4, before pouring concrete, the T-shaped track groove is welded to the structural steel bars of the precast concrete slab, and the lower edge of the web of the T-shaped track groove is ensured to be flush with the lower edge of the precast concrete slab.

7. The construction method of the prefabricated composite beam resistant to pull-out but not resistant to shear in the negative moment zone according to claim 4, characterized in that: After the assembly is completed in step S5, the prefabricated composite beams resistant to pull-out but not resistant to shear in the negative moment zone are transported to the construction site in the form of integral composite beam sections and installed in the negative moment zone of the continuous beam bridge.

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