Prestressed composite beam

Abstract

The utility model provides a prestressed composite beam, the web of main beam body (1) is provided with the flange (4) that stretches out to the outside, the beam body longitudinal reinforcement (11) of main beam body (1) inside includes ordinary reinforcement (13) and prestressed reinforcement (14), the ordinary reinforcement (13) is symmetrically arranged in the web of main beam body (1), the prestressed reinforcement (14) is symmetrically arranged in the beam bottom, the beam body stirrup (12) stretches out the top bearing surface (2) of main beam body (1) and becomes the cast-in-place part (5). Compared with prior art, the beneficial effects are: improving the shearing capacity, meeting the installation demand of large-span composite slab and being free from field formwork and support operation. Not only free from formwork construction, but also free from support, reducing the engineering quantity, shortening the construction period and saving the cost. The prestressed reinforcement symmetrically arranged in the beam bottom can balance the bending moment produced by external load, and through the cooperative work of prestressed reinforcement and ordinary reinforcement realizes efficient stress, ensures the economy and safety.

Description

Technical Field

[0001] This utility model belongs to the field of prefabricated buildings, specifically relating to a prestressed composite beam. Background Technology

[0002] Composite beams consist of precast beams and cast-in-place sections. In existing composite straight beam construction, the two ends of the precast beam are first supported by two columns, and then the cast-in-place section is poured directly on top of the precast beam. When the span of the precast beam is large, relying solely on the support of the prestressed composite beam can easily damage the precast beam during pouring, affecting the quality of the composite beam. Therefore, due to the limitations of the precast beam's stress distribution, temporary support devices need to be installed on the underside of the precast beam, especially when the span and upper load are large, requiring even more frequent installations of temporary support devices. This increases additional work, extends the construction period, and is costly. Summary of the Invention

[0003] This utility model provides a prestressed composite beam; the main beam has a top bearing surface and a bottom support surface, and the web of the main beam has outwardly extending flanges; the main beam is formed by binding internal longitudinal reinforcement, beam stirrups, flange longitudinal reinforcement, and flange stirrups into a frame and then casting it integrally with cement. The internal longitudinal reinforcement of the main beam includes ordinary steel bars and prestressed steel bars. The ordinary steel bars are symmetrically arranged on the web of the main beam, and the prestressed steel bars are symmetrically arranged at the bottom of the beam. The beam stirrups extend beyond the top bearing surface of the main beam to form the cast-in-place part anchored to the composite slab; the bottom support surface sits on a support. The flanges are used to support the longitudinal ribs of the matching composite slab. The ribs of the composite slab can rest on the horizontal surface of the flanges. The dimensions of the composite slab and the composite beam are matched according to design requirements to meet the installation requirements of large-span composite slabs and to eliminate the need for on-site formwork and support operations.

[0004] Furthermore, the stirrups of the main beam are densified near the supports or at the column joints to improve shear resistance. The spacing in the non-densified zone is no more than 200mm, and the spacing in the densified zone is no more than 100mm. The densified stirrups can improve the deformation resistance and stability of the composite beam at the joints.

[0005] Furthermore, the longitudinal reinforcement of the flange is arranged parallel to the longitudinal reinforcement of the beam, and the flange stirrups are arranged at intervals along the longitudinal direction of the main beam, with the spacing of the flange stirrups not exceeding 150mm.

[0006] Furthermore, the main beam includes flanges on one or both sides of the web. The flange stirrups are formed by bending a single steel bar. After the concrete is poured, the flange stirrups and flange longitudinal bars are embedded in the flange, making the structure more regular and easier to hoist and construct on site.

[0007] Furthermore, the prestressed steel reinforcement includes at least two sets of prestressed steel strand bundles symmetrically arranged at the bottom of the main beam. The prestressed steel strands are parabolic or straight to balance the bending moment generated by the external load.

[0008] Furthermore, the bottom support surface and the two anchoring end faces of the main beam are roughened by chiseling, and the stability of the anchoring structure is enhanced after grouting.

[0009] Compared with existing technologies, the advantages of this utility model are as follows: the web of the prestressed composite beam is provided with outwardly extending flanges; longitudinal ribs are used to support the matching composite slab; the stirrups of the beam extend beyond the top bearing surface of the main beam to become the cast-in-place part anchored to the composite slab; the ribs of the composite slab can rest on the horizontal plane of the flanges; the dimensions of the composite slab and the composite beam are matched according to design requirements, improving shear resistance, meeting the installation requirements of large-span composite slabs, and eliminating the need for on-site formwork and support operations. Not only is formwork-free construction possible, but support is also eliminated, reducing the workload, shortening the construction period, and saving costs.

[0010] The prestressed steel bars symmetrically arranged at the bottom of the beam can balance the bending moment generated by external loads. The efficient stress distribution is achieved through the synergistic work of prestressed steel bars and ordinary steel bars, ensuring both economy and safety. Attached Figure Description

[0011] Figure 1 This is the front view of this utility model.

[0012] Figure 2 This is a side sectional view of the present invention.

[0013] Figure 3 This is a top view of the present invention.

[0014] In the figure: 1 Main beam body, 2 Top bearing surface, 3 Bottom supporting surface, 4 Flange, 5 Cast-in-place part, 11 Beam longitudinal reinforcement, 12 Beam stirrups, 13 Ordinary steel bars, 14 Prestressed steel bars, 41 Flange longitudinal reinforcement, 42 Flange stirrups. Detailed Implementation

[0015] The present invention will be further explained below with reference to specific embodiments.

[0016] Reference Figure 1 , Figure 2 and Figure 3It is known that a prestressed composite beam has a main beam body 1 with a top bearing surface 2 and a bottom support surface 3. The main beam body 1 has an outwardly extending flange 4 on its web. The main beam body 1 is formed by binding internal longitudinal reinforcement 11, beam stirrups 12, flange longitudinal reinforcement 41 and flange stirrups 42 into a frame and then casting it integrally with cement. The internal longitudinal reinforcement 11 of the main beam body 1 includes ordinary steel bars 13 and prestressed steel bars 14. The ordinary steel bars 13 are symmetrically arranged on the web of the main beam body 1, and the prestressed steel bars 14 are symmetrically arranged at the bottom of the beam. The beam stirrups 12 extend out of the top bearing surface 2 of the main beam body 1 to form a cast-in-place part 5 that is anchored to the composite slab in place. The bottom support surface 3 sits on a support. The flange 4 is used to support the longitudinal ribs of the matching composite slab. The ribs of the composite slab can be placed on the horizontal surface of the flange 4. The dimensions of the composite slab and the composite beam are matched according to the design requirements to meet the installation requirements of large-span composite slabs and to eliminate the need for on-site formwork and support operations.

[0017] The stirrups 12 of the main beam 1 are densified near the support or at the column joint to improve shear resistance. The spacing in the non-densified zone is no more than 200mm, and the spacing in the densified zone is no more than 100mm. The densified stirrups can improve the deformation resistance and stability of the composite beam at the joint.

[0018] The longitudinal reinforcement 41 of the flange is arranged parallel to the longitudinal reinforcement 11 of the beam body, and the longitudinal stirrups 42 of the flange are arranged at intervals along the longitudinal direction of the main beam body 1, with the spacing of the flange stirrups 42 not exceeding 150mm.

[0019] The main beam 1 includes flanges 4 on one or both sides of the web. The flange stirrups 42 are formed by bending a whole steel bar. After the concrete is poured, the flange stirrups 42 and the flange longitudinal bars 41 are embedded in the flanges 4.

[0020] The prestressed steel bars 14 include at least two sets of prestressed steel strand bundles symmetrically arranged at the bottom of the main beam 1, and are made by pre-tensioning. The prestressed steel strands are parabolic or straight to balance the bending moment generated by the external load.

[0021] The bottom support surface 3 and the two anchoring end faces of the main beam 1 are roughened by chiseling, and the stability of the anchoring structure is enhanced after grouting.

[0022] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope of the technology disclosed in the present utility model, based on the technical solution and inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A prestressed composite beam, characterized in that, The main beam (1) has a top bearing surface (2) and a bottom support surface (3). The main beam (1) has an outwardly extending flange (4) on its web. The main beam (1) is integrally formed by pouring concrete from the internal beam longitudinal reinforcement (11), beam stirrups (12), flange longitudinal reinforcement (41) and flange stirrups (42). The beam longitudinal reinforcement (11) inside the main beam (1) includes ordinary steel bars (13) and prestressed steel bars (14). The ordinary steel bars (13) are symmetrically arranged on the web of the main beam (1), and the prestressed steel bars (14) are symmetrically arranged at the bottom of the beam. The beam stirrups (12) extend out of the top bearing surface (2) of the main beam (1) to become the cast-in-place part (5).

2. The prestressed composite beam according to claim 1, characterized in that, The stirrups (12) of the main beam (1) are densified near the support or at the column node.

3. The prestressed composite beam according to claim 1, characterized in that, The longitudinal reinforcement bars (41) of the flange are arranged parallel to the longitudinal reinforcement bars (11) of the beam body, and the longitudinal stirrups (42) of the flange are arranged at intervals along the main beam body (1).

4. The prestressed composite beam according to claim 1, characterized in that, The main beam (1) includes flanges (4) set on one or both sides of the web. The flange stirrups (42) are formed by bending a whole steel bar. The flange stirrups (42) and the flange longitudinal bars (41) are both embedded in the flange (4).

5. The prestressed composite beam according to claim 1, characterized in that, The prestressed steel bars (14) include at least two sets of prestressed steel strand bundles symmetrically arranged at the bottom of the main beam (1).

6. The prestressed composite beam according to claim 1, characterized in that, The bottom support surface (3) and the two anchoring end faces of the main beam (1) are roughened by chiseling.

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