Precast beam with steel-concrete composite structure

Abstract

The invention relates to the technical field of fabricated building structures, in particular to a steel-concrete composite structure precast beam. The steel-concrete composite structure precast beam adopts the combination of a reinforced concrete beam section, a beam end steel structure connecting assembly and a beam bottom steel structure embedded part, cast-in-place concrete operation of beam column joints, beam wall joints and beam plate joints is basically canceled, compared with traditional wet operation, the amount is reduced by more than 80%, single-joint construction time is shortened, and construction waste is reduced by more than 50%; the concrete cantilever lug plates directly bear the load of the floor slab, erection of an all-round scaffold is omitted, the beam ends are installed through the beam end steel structure connecting assemblies to form a stable frame structure in time, the temporary supporting cost is saved by 12%-16%, and the installation efficiency of the floor slab and the wallboard is remarkably improved; the installation of the main body structure of the steel-concrete composite structure precast beam only needs hoisting team operation, and most processes are integrated in components by a component factory, so that the multi-process integration and cross operation are reduced by 80%, the on-site personnel density is reduced, and the labor cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of assembled building structures, and in particular to a prefabricated beam of a steel-concrete composite structure. Background Art

[0002] With the acceleration of the process of building industrialization, precast concrete beams, as the core horizontal components of prefabricated structures, their connection efficiency and structural performance directly affect the construction speed and building quality.

[0003] In current prefabricated buildings, the application of precast concrete beams still relies on traditional connection and construction methods, which has the following defects: (1) In terms of floor slab installation, a large number of temporary supports are required to bear the floor slab load, which prolongs the construction period. The erection and dismantling are time-consuming and labor-intensive, which restricts the construction progress.

[0004] (2) In beam-column joint connections, wet working methods are often used, and the on-site pouring of concrete is cumbersome. The construction quality of traditional wet working joints is greatly affected by the on-site environment, the force transmission path is unclear, there are structural safety hazards, and the reliability of beam-column joint connections is insufficient. The proportion of wet working is high: the construction time of wet working joints is 2.1 times that of dry connections, and it is easy to generate construction waste, which does not conform to the concept of green construction.

[0005] (3) The beam-wall connection has poor flexibility, lacks standardized embedded structures, and has low wall installation accuracy and insufficient stability.

[0006] Based on the above, it can be seen that the current technical system still has a series of problems that need to be solved, such as low floor installation efficiency, high temporary support costs, insufficient reliability of beam-column joint connections, and a high proportion of wet work. Therefore, a prefabricated steel-concrete composite structural beam is urgently needed to solve the problems existing in the existing technology. Summary of the Invention

[0007] The present invention aims to provide a prefabricated steel-concrete composite structure beam, which is a solution to the existing system technical problems and is optimized in multiple ways. It can achieve a higher degree of on-site assembly, no support or formwork required, and fully dry operation of the nodes. The specific technical solution is as follows: A prefabricated beam of a steel-concrete composite structure, comprising a reinforced concrete beam section, a steel structure connection assembly at the beam end, and a steel structure embedded part at the beam bottom; The reinforced concrete beam section includes a beam section skeleton reinforcement and a concrete layer; the beam section skeleton reinforcement includes interconnected beam longitudinal reinforcement and beam stirrups; The beam end steel structure connection assembly is arranged at at least one end portion of the reinforced concrete beam section; The beam bottom steel structure embedded parts are arranged at the beam bottom of the reinforced concrete beam section; The side of the reinforced concrete beam section is provided with a concrete overhanging lug plate capable of lapping the floor, the concrete overhanging lug plate comprises overhanging lug plate skeleton steel bars and a concrete layer, the overhanging lug plate skeleton steel bars comprise overhanging lug longitudinal reinforcement and overhanging lug stirrups connected with each other; at least one connecting piece corresponding to the mounting hole reserved on the floor is arranged on the concrete overhanging lug plate. At least one steel connecting groove is arranged on the top of the reinforced concrete beam section, and the overhanging steel bars on the floor are connected with the steel connecting groove.

[0008] The steel-concrete composite structure prefabricated beam adopts the combination of the reinforced concrete beam section, the beam end steel structure connecting assembly and the beam bottom steel structure embedded part, the beam column joint, the beam wall joint and the beam plate joint basically cancel the cast-in-place concrete operation, the wet operation amount of the traditional fabricated concrete structure is reduced by more than 80%, the construction time of a single joint is shortened, and the construction waste is reduced by more than 50%; the floor load is directly borne by the concrete overhanging lug plate, the erection of the full scaffolding is cancelled, the beam end forms a stable frame structure immediately after being installed by the beam end steel structure connecting assembly, the temporary support cost is saved by 12-16%, and the installation efficiency of the floor and the wall plate is significantly improved; the installation of the main structure of the steel-concrete composite structure prefabricated beam only needs the hoisting team operation, and does not need the cooperation of the steel reinforcement worker, the formwork worker and the concrete worker, most of the processes have been integrated in the component in the component factory, the multi-process integration reduces the cross operation by 80%, which is beneficial to reducing the on-site personnel density and saving the labor cost.

[0009] Preferably, an anchor head is arranged on the connecting piece on the concrete overhanging lug plate; the connecting piece is arranged in one-to-one correspondence with the mounting hole reserved on the floor. The connection stability of the concrete overhanging lug plate and the floor is further strengthened.

[0010] Preferably, an oil felt and a cement mortar leveling layer are arranged on the concrete overhanging lug plate; a filling layer, a PE rod, a sealant layer and a slurry layer are further arranged between the connecting piece and the mounting hole reserved on the floor to form a consolidation joint; a mortar layer is arranged on the outside of the consolidation joint. The arrangement of the consolidation joint further enhances the stability of the connection; the mortar layer can effectively correct the appearance and prolong the service life of the consolidation joint.

[0011] Preferably, the overhanging steel bars on the floor respectively extend out of the surface layer and the bottom layer; the overhanging steel bars extend into the steel connecting groove for connection; a concrete layer is arranged at the connection between the overhanging steel bars on the floor and the steel connecting groove to reinforce the connection.

[0012] Preferably, the end of the surface steel bar on the floor is bent to increase the anchoring length or is connected with the surface steel bar of the adjacent floor in an integral whole by mechanical connection or welding connection.

[0013] Preferably, the beam-end steel connection assembly consists of H-shaped steel with cut ends, the main body of which is enclosed within the reinforced concrete beam section, with the web exposed outside the reinforced concrete beam section. Connection holes are provided in the exposed web, and reinforced connectors are provided on the surface of the H-shaped steel. The combination of high-strength bolts and connection holes enables dry connection between precast beams and columns; the reinforced connectors are designed to enhance their interoperability with concrete.

[0014] Preferably, the pre-embedded steel structure components at the bottom of the beam include an embedded steel plate and a gusset plate mounted on the embedded steel plate. The embedded steel plate is connected to the reinforced concrete beam section via embedded anchor bars. The ends of the embedded anchor bars are provided with a bend or an anchor head, and the embedded anchor bars are fixedly connected to the embedded steel plate via plug welding. The prefabricated wall panels can be connected to the gusset plate via pin joints, which facilitates operation.

[0015] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 Schematic diagram of the steel-concrete composite precast beam in this embodiment; Figure 2 yes Figure 1 Front view of the steel-concrete composite precast beam structure; Figure 3 yes Figure 1 Top view of the steel-concrete composite precast beam structure; Figure 4 yes Figure 1 Schematic diagram of embedded parts at the bottom of the center beam; Figure 5 yes Figure 1 Schematic diagram of the center beam end connection assembly; Figure 6 yes Figure 1 Schematic diagram of the center beam-slab connection node structure; Figure 7 yes Figure 1 Top view of the center beam-slab connection node; Among them, 1. Reinforced concrete beam section, 101. Beam longitudinal reinforcement, 102. Beam stirrups; 2. Beam end steel structure connection components, 201. Steel joint, 202. Reinforced connector, 203. Connection hole; 3. Beam bottom steel structure embedded parts, 301. Node plate, 302. Embedded steel plate, 303. Embedded anchor bar; 4. Concrete cantilever ear plate, 401. Cantilever ear longitudinal reinforcement, 402. Cantilever ear stirrups; 5. Connectors, 501. Anchor head, 502. Filling layer, 503. PE rod, 504. Sealant layer, 505. Mortar layer, 506. Slurry layer, 507. Cement mortar leveling layer, 508. Roofing felt; 6. Steel bar connection groove; 7. Precast floor slab, 701. Floor slab steel bar, 702. Concrete layer. DETAILED DESCRIPTION

[0017] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims.

[0018] Example: See also Figures 1-7 A prefabricated steel-concrete composite beam specifically includes a reinforced concrete beam section 1, a beam end steel structure connection component 2, and a beam bottom steel structure embedded part 3. The detailed structure is as follows: The reinforced concrete beam section 1 is the main structure, which includes a beam skeleton reinforcement and a concrete layer; the beam skeleton reinforcement includes interconnected beam longitudinal reinforcement 101 and beam stirrups 102, see Figure 1 and Figure 2 Concrete with strength grade C30 or above is used for pouring. The beam body is equipped with HRB400 or above longitudinal reinforcement 101 and HPB300 / HRB400 grade stirrups 102. The diameter of the longitudinal reinforcement is generally selected to be φ20-25mm based on force calculations. The stirrup diameter shall not be less than φ8mm, and the spacing shall be set according to seismic requirements.

[0019] The side of the reinforced concrete beam section 1 is provided with a concrete cantilever ear plate 4 that can overlap the floor slab. The concrete cantilever ear plate 4 includes a cantilever ear plate skeleton steel bar and a concrete layer. The cantilever ear plate skeleton steel bar includes a cantilever ear longitudinal bar 401 and a cantilever ear stirrup 402 that are interconnected. The concrete cantilever ear plate 4 is provided with at least one connector 5 that is arranged corresponding to the installation hole reserved on the floor slab (prefabricated floor slab can be used here). Preferably, the connector 5 on the concrete cantilever ear plate 4 is provided with an anchor head 501. The connector 5 is arranged in a one-to-one correspondence with the installation hole reserved on the floor slab. The concrete cantilever ear plate 4 is provided with a felt 508 and a cement mortar leveling layer 507. A filling layer 502, a PE rod 503, a sealant layer 504 and a slurry layer 506 are also provided between the connector 5 and the installation hole reserved on the floor slab to form a consolidation node. A mortar layer 505 is provided on the outside of the consolidation node. For details, see Figure 6The overhanging steel bars on the floor respectively extend out of the surface layer and the bottom layer; the overhanging steel bars extend into the steel bar connecting groove for connection; the connection between the overhanging steel bars on the floor and the steel bar connecting groove 6 is provided with a concrete layer 702 for reinforcing the connection, and details are shown in Figure 7 The end of the floor surface steel bar is connected to the surface layer steel bar of the adjacent floor in an integral manner by adopting steel bar bending to increase the anchoring length or by adopting mechanical connection or welding connection. In this embodiment, the concrete overhanging lug plate 4 is provided with an overhanging lug longitudinal bar 401 and an overhanging lug stirrup 402, and details are shown in Figure 3 The size and reinforcement of the overhanging lug are determined according to structural calculation; the overhanging lug top surface is pre-buried with a fixed bolt (i.e. a connecting piece 5) with an anchor head, and the bolt spacing is one-to-one corresponding to the reserved hole channel on the floor.

[0020] The beam end steel structure connecting assembly 2 is arranged at least at one end of the reinforced concrete beam section 1. In this embodiment, the beam end steel structure connecting assembly 2 is shown in detail in Figure 5 , and specifically adopts a profile steel joint 201, i.e. an H-shaped steel of Q355B grade with the end portion being cut, the main body portion of which is covered in the reinforced concrete beam section 1 and the web is exposed to the reinforced concrete beam section 1; a connecting hole 203 is formed in the exposed web, which is preferably a high-precision bolt hole for passing a 10.9-grade high-strength bolt; the surface of the H-shaped steel is provided with a reinforcing connecting piece 202, which is preferably a Φ19*80mm bolt, and the spacing is arranged according to the shear resistance requirement of the steel-concrete interface to enhance the cooperative working performance with the concrete.

[0021] The beam bottom steel structure embedded part 3 is arranged at the beam bottom of the reinforced concrete beam section 1. In this embodiment, the beam bottom steel structure embedded part 3 is shown in detail in Figure 4 , and specifically includes a pre-buried steel plate 302 and a node plate 301 arranged on the pre-buried steel plate 302; the pre-buried steel plate 302 is connected to the reinforced concrete beam section 1 through a pre-buried anchor bar 303; the end of the pre-buried anchor bar 303 is provided with a bent portion or an anchor head, and the pre-buried anchor bar 303 is fixedly connected to the pre-buried steel plate 302 through punch plug welding. Further preferably, the pre-buried steel plate is of Q355B grade, the pre-buried anchor bar is of HRB400 grade, the pre-buried steel plate has a thickness of 16-25mm, the pre-buried anchor bar is fixed through punch plug welding with a Φ16-Φ20mm pre-buried anchor bar, and the end of the pre-buried anchor bar can be bent or provided with an anchor head to shorten the anchoring length; the node plate is used for wall plate pin shaft connection, and the node plate is not temporarily welded on the mold table contact surface during horizontal production, and is subsequently supplemented.

[0022] The top of the reinforced concrete beam section 1 is provided with at least one steel bar connecting groove 6, and the overhanging steel bar on the floor is connected to the steel bar connecting groove 6.

[0023] The application of the technical solution of this embodiment has the following factory prefabrication key procedures and site construction operation processes: I. Factory prefabrication key procedures: The beam end steel connection component 2 (i.e., the beam end H-beam) is precisely cut in a specialized factory, with the ends cut to ensure smoothness of the connection surface. Gas shielded welding is used for welding the reinforcement connector 202 (i.e., the welding studs), with weld quality reaching level 2 or higher. Connection holes 203 (i.e., the web bolt holes) are precision-engineered. The embedded steel plate 302 and embedded anchor bar 303 of the beam bottom embedded component are connected by plug welding. After welding, the weld slag is cleaned and the weld quality is inspected.

[0024] High-precision molds are used in the production of precast beams for steel-concrete composite structures. H-shaped steel beams at the beam ends are fixed according to the designed layout, ensuring accurate embedment depth and exposed web positioning. When tying the beam longitudinal reinforcement 101, the beam longitudinal reinforcement 101 is welded to the upper and lower flanges of the H-shaped steel, with a weld length of ≥5d (d is the longitudinal bar diameter). In the area of ​​the concrete cantilever lug 4, cantilever lug longitudinal reinforcement 401 and cantilever lug stirrups 402 are simultaneously tied to ensure the required steel cover thickness. Where steel bar connection grooves 6 are required, the reserved groove size matches the floor slab reinforcement diameter to ensure continuous steel reinforcement on the beam.

[0025] 2. On-site construction operation process: Before hoisting, check the position of the column connection node, use the special hoisting equipment in the existing technology to lift the reinforced concrete beam section 1 to the installation position, align the exposed web of the H-shaped steel at the beam end with the column node, adjust the elevation and horizontality of the beam after temporary fixation, and then tighten the high-strength bolts in stages.

[0026] Before installing the floor slab, a layer of felt 508 and a 20mm-thick cement mortar leveling layer 507 are laid sequentially on the concrete cantilever lugs 4. After curing to a strength of 15MPa or higher, the precast floor slab 7 is hoisted, aligning the pre-reserved holes in the floor slab with the connectors 5 (i.e., the lug fixing bolts). The gap between the precast floor slab 7 and the concrete cantilever lugs 4 is filled with a filler layer 502 (i.e., polystyrene board 2). PE rods 503 and a sealant layer 504 are embedded on the outside. A grout layer 506 (i.e., CGM grouting material) is poured into the bolt holes. After curing, the surface is smoothed with a filler mortar layer 505. For high-stress areas, the floor slab reinforcement 701 on the surface layer of the precast floor slab needs to be extended by the Lae length (seismic anchorage length) and inserted into the beam top reinforcement connection groove 6. The floor slab reinforcement 701 on the bottom layer needs to be extended short. The ends of the slab surface reinforcement on the floor slab are bent, mechanically connected, or welded to form a whole with the adjacent floor slab reinforcement. A concrete layer 702 (i.e., UHPC layer) is poured in the groove and cured to the design strength.

[0027] If a wall panel is required below reinforced concrete beam segment 1, weld gusset plate 301 to embedded steel plate 302 according to the wall panel's location. The weld length should be ≥ 10d (d is the gusset plate thickness). The wall panel is fixed to the gusset plate via a pin.

[0028] The technical solution of this embodiment is specifically: The side of the main reinforced concrete beam section needs to be further designed with concrete cantilever ear plates according to the structural layout, which are used to overlap the precast floor slabs and achieve support-free operation; the steel structure connection components at the beam ends are arranged at both ends of the beam length, and the longitudinal reinforcement, stirrups and bent steel bars are arranged between them according to structural calculations. The longitudinal reinforcement and bent steel bars need to be precisely welded to the upper and lower flange plates of the end assembly according to their position (weld length ≥ 5d (rebar diameter)).

[0029] The concrete cantilever ear plate needs to be equipped with stirrups and longitudinal reinforcement according to structural calculations, and high-strength connecting bolts (M20 grade, with anchor heads) are embedded in the top of the plate to match the reserved channels of the prefabricated floor slabs. For large load areas, a steel bar connection groove is opened at the top of the main beam section, and the groove size matches the diameter of the floor slab steel bar. The iron steel bars on the beam are retained, and the floor slab steel bars can be connected with the adjacent floor slabs by hook lap joints, welding or mechanical connection to form a continuous force system.

[0030] Key nodes: The beam end connection assembly uses H-shaped steel with cut ends. The main section is embedded in the concrete, with only the processed web exposed as the connection surface. High-precision bolt holes are provided on the exposed web. Studs are welded to the sides of the H-shaped steel web embedded in the concrete, significantly improving the shear resistance of the steel-concrete interface. The embedded parts at the bottom of the beam of the present invention are composed of embedded steel plates and welded node plates. The embedded steel plates are fixed to the anchor bars by perforated plug welding. Considering the production process limitations of the flat formwork, only embedded plates are set on the contact surface of the formwork. The position is adjusted according to the wall layout, and the node plates are welded later.

[0031] Applying the technical solution of this embodiment has the following advantages: First, a fully dry construction system: Beam-column joints (H-steel bolt connections), beam-wall joints (embedded pin connections), and beam-slab joints (bolt-grouting / UHPC troughs) virtually eliminate cast-in-place concrete work. Compared to traditional prefabricated concrete structures, wet work is reduced by over 80%, single-joint construction time is shortened, and construction waste is reduced by over 50%.

[0032] Second, a support-free structural system: Concrete cantilevered lugs directly bear the floor load, eliminating the need for full-height scaffolding. H-shaped steel end joints are installed at the beam ends to create a stable frame structure. This process reduces temporary support costs by 12-16% and significantly improves the efficiency of floor and wall panel installation.

[0033] Third, construction work and manpower are optimized: The main structure installation only requires the hoisting team, eliminating the need for reinforcement workers, formwork workers, and concrete workers. Because most processes are integrated into the components by the component factory, cross-operation is reduced by 80%, helping to reduce on-site staff density and save labor costs.

[0034] Fourth, the structural reliability is improved: through the steel bar and the bolt nail to strengthen the steel and the mixed combination interface cooperation performance, realizes the effective force transmission path, and the steel structure connection technology is quite mature, the steel and the mixed combination prefabricated beam node calculation model basically can refer to the steel structure logic to design.

[0035] The embodiment realizes the efficiency and the structural reliability of the prefabricated beam construction through the standardization prefabrication and the dry type connection, is applicable to the beam component installation of the low layer and the multilayer assembly type building.

[0036] The above only for the preferred embodiment of the application has, and does not for limiting the application, for the person skilled in the art, the application can have various changes and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application should be included in the protection scope of the application.

Claims

1. A prefabricated beam of a steel-concrete composite structure, characterized in that: It includes a reinforced concrete beam section (1), a beam end steel structure connection component (2), and a beam bottom steel structure embedded part (3); The reinforced concrete beam segment (1) comprises a beam segment skeleton reinforcement and a concrete layer; the beam segment skeleton reinforcement comprises beam longitudinal reinforcement (101) and beam stirrups (102) connected to each other; The beam end steel structure connection assembly (2) is arranged at at least one end of the reinforced concrete beam section (1); The beam bottom steel structure embedded part (3) is arranged at the beam bottom of the reinforced concrete beam section (1); The side of the reinforced concrete beam section (1) is provided with a concrete cantilevered ear plate (4) capable of overlapping the floor slab, the concrete cantilevered ear plate (4) comprising a cantilevered ear plate skeleton reinforcement and a concrete layer, the cantilevered ear plate skeleton reinforcement comprising interconnected cantilevered ear longitudinal reinforcement (401) and cantilevered ear stirrups (402); the concrete cantilevered ear plate (4) is provided with at least one connecting piece (5) corresponding to a mounting hole reserved on the floor slab; At least one steel bar connection groove (6) is provided on the top of the reinforced concrete beam section (1), and the protruding steel bars on the floor slab are connected to the steel bar connection groove (6).

2. The prefabricated steel-concrete composite structure beam according to claim 1, characterized in that: The connecting member (5) is provided with an anchor head (501); The connecting pieces (5) are arranged in one-to-one correspondence with the mounting holes reserved on the floor slab.

3. The prefabricated steel-concrete composite structure beam according to claim 2, characterized in that: A linoleum felt (508) and a cement mortar leveling layer (507) are provided on the concrete cantilevered ear plate (4); A filling layer (502), a PE rod (503), a sealing adhesive layer (504) and a slurry layer (506) are provided between the connecting piece (5) and the mounting hole reserved on the floor slab to form a consolidation node; a mortar layer (505) is provided on the outside of the consolidation node.

4. The prefabricated steel-concrete composite structure beam according to claim 3, characterized in that: The protruding steel bars on the floor slab extend out from the surface layer and the bottom layer respectively; the protruding steel bars extend into the steel bar connection groove for connection; A concrete layer (702) is provided at the connection between the extended steel bars on the floor slab and the steel bar connection groove (6) to reinforce the connection.

5. The prefabricated steel-concrete composite structure beam according to claim 4, characterized in that: The ends of the surface reinforcement on the floor slab are connected to the surface reinforcement of the adjacent floor slab into a whole by bending the reinforcement to increase the anchorage length or by mechanical connection or welding.

6. The precast steel-concrete composite structure beam according to any one of claims 1 to 5, characterized in that: The beam end steel structure connection assembly (2) is an H-shaped steel with cut ends, the main body of which is enclosed in the reinforced concrete beam section (1) and the web is exposed outside the reinforced concrete beam section (1); a connection hole (203) is provided on the exposed web; and a reinforcing connector (202) is provided on the surface of the H-shaped steel.

7. The precast steel-concrete composite structure beam according to any one of claims 1 to 5, characterized in that: The beam bottom steel structure embedded part (3) comprises an embedded steel plate (302) and a node plate (301) arranged on the embedded steel plate (302); the embedded steel plate (302) is connected to the reinforced concrete beam section (1) via embedded anchor bars (303); the ends of the embedded anchor bars (303) are provided with a bent portion or an anchor head, and the embedded anchor bars (303) are fixedly connected to the embedded steel plate (302) by piercing plug welding.

Images