Maintenance-free steel frame beam and steel floor beam and design method thereof

Abstract

The invention relates to the technical field of component design and machining, in particular to a maintenance-free steel frame beam, a maintenance-free steel floor beam and a design method of the maintenance-free steel frame beam and the maintenance-free steel floor beam. The lifting seat is fixedly arranged at the upper flange of the H-shaped steel beam; the hanging seat is connected with the outer plate body; the outer plate body is of a U-shaped section structure and comprises a first side plate, a second side plate and a bottom plate. The top ends of the first side plate and the second side plate are connected with the lifting seat; the first side plate comprises a first side plate concrete layer and a first side plate reinforcing mesh; the second side plate comprises a second side plate concrete layer and a second side plate reinforcing mesh; the bottom plate comprises bottom plate concrete and a bottom plate reinforcing mesh. Compared with the prior art, the steel plate has the characteristics of light dead weight, high strength, good ductility and excellent anti-seismic property.

Description

Technical Field

[0001] The present invention relates to the technical field of component design and processing, in particular to a maintenance-free steel frame beam and steel floor beam and a design method thereof. Background Art

[0002] Traditional H-shaped steel frame beams offer advantages such as light weight, high strength, superior seismic performance, and easy construction. However, these components also suffer from common steel structural issues: poor fire and corrosion resistance, requiring the application of fire-retardant coatings and fireproof panels. This, in turn, incurs maintenance costs, making them less cost-effective.

[0003] Traditional cast-in-place reinforced concrete beams and steel-concrete beams offer strong bearing capacity, excellent durability and fire resistance, readily available materials, low subsequent maintenance costs, and excellent economic efficiency. However, these components also have the following shortcomings: 1. Their heavy weight complicates foundation design; 2. Their poor crack resistance makes them prone to cracking during use, impacting the durability and aesthetics of the structure; 3. Their construction is complex, requiring multiple steps including formwork support, steel bar tying, concrete pouring, and curing, resulting in a long construction period and significant impact from seasonal and weather conditions. Summary of the Invention

[0004] The object of the present invention is to provide a maintenance-free steel frame beam and steel floor beam and a design method thereof, so as to solve at least one technical problem existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides a maintenance-free steel frame beam, comprising an outer plate, a hanger and an H-shaped steel beam; The hanger is fixedly arranged on the upper flange of the H-shaped steel beam; The hanger is connected to the outer plate.

[0006] Furthermore, the outer plate body is a U-shaped cross-section structure, comprising a first side plate, a second side plate and a bottom plate; Top ends of the first side plate and the second side plate are connected to the hanging seat.

[0007] Furthermore, the first side panel comprises a first side panel concrete layer and a first side panel steel mesh; The second side panel comprises a second side panel concrete layer and a second side panel steel mesh; The bottom plate includes bottom plate concrete and bottom plate steel mesh; The first side plate steel mesh, the second side plate steel mesh and the bottom plate steel mesh are respectively embedded in the first side plate concrete layer, the second side plate concrete layer and the bottom plate concrete.

[0008] Furthermore, the first side panel, the second side panel and the bottom panel are an integrated structure; The first side slab concrete layer and the second side slab concrete layer include a factory prefabricated portion and a factory cast portion; The factory prefabricated part is integrally cast with the base plate concrete; The factory casting part wraps the upper ends of the first side plate steel mesh and the second side plate steel mesh; The factory casting portion is cast after the upper ends of the first side plate steel mesh and the second side plate steel mesh are connected to the hanging seat.

[0009] Furthermore, the hanger is an L-shaped structure, comprising a vertical portion and a horizontal portion; The upper end of the vertical portion is welded to the lower end surface of the upper flange of the H-shaped steel beam; The lower end of the vertical portion is integrally connected to one end of the horizontal portion; The horizontal portion is provided with a through hole for the steel bar head at the end of the steel mesh to pass through; After the steel bar head passes through the horizontal portion, the lower end surface of the horizontal portion abuts against the upper end surface of the factory prefabricated portion, and the steel bar head and the horizontal portion are welded together using welding materials.

[0010] Furthermore, inspection openings are provided on the first side panel and the second side panel, and fireproof panels are detachably provided on the inspection openings.

[0011] Furthermore, an aerated block is provided between the outer plate and the H-shaped steel beam to enhance the fire resistance of the prefabricated beam and provide a single-sided formwork for the casting of the first side panel and the second side panel.

[0012] Furthermore, the H-shaped steel beam is provided with stiffening ribs for strengthening the torsional rigidity of the H-shaped steel beam and dividing the aerated block into a plurality of small blocks, thereby facilitating the installation of the aerated block; Ends of the reinforcing ribs are inserted into the first side panel concrete layer and the second side panel concrete layer and are welded to the first side panel steel mesh and the second side panel steel mesh.

[0013] Furthermore, the first side panel and the bottom panel are rotatably connected via a first hinge; The second side panel and the bottom panel are rotatably connected via a second hinge.

[0014] Furthermore, one end of the first hinge is fixedly connected to the first side plate steel mesh, and the other end is fixedly connected to the bottom plate steel mesh; One end of the second hinge is fixedly connected to the second side plate steel mesh, and the other end is fixedly connected to the bottom plate steel mesh.

[0015] Furthermore, a first angle steel holder is fixedly provided on one end of the first side plate steel mesh away from the first hinge; A second angle steel holder is fixedly provided on one end of the second side plate steel mesh away from the second hinge; The first angle steel holder and the second angle steel holder are placed on the hanging seat.

[0016] Furthermore, a first edge sealing plate is fixedly provided on one end of the first side plate steel mesh away from the first hinge; A second edge-sealing plate is fixedly provided on one end of the second side plate steel mesh away from the second hinge; The first edge sealing plate and the second edge sealing plate are L-shaped and are respectively arranged at the outermost ends of the first side plate and the second side plate.

[0017] Furthermore, the first edge-sealing plate includes a first edge-sealing top plate and a first edge-sealing side plate; The first edge-sealed top plate is configured to protect the upper edge of the first side plate concrete layer from collision damage or wear during loading and unloading; The first edge-sealed side plate is exposed on the outward side of the concrete layer of the first side plate; The second edge-sealing plate includes a second edge-sealing top plate and a second edge-sealing side plate; The second edge-sealed top plate is provided to protect the upper edge of the second side plate concrete layer from collision damage or wear during loading and unloading; The second edge-sealed side panel is exposed on the outward side of the concrete layer of the second side panel.

[0018] Furthermore, it also includes a rotating ejector pin assembly; The rotating ejector pin assembly is provided in plurality on the lower end surface of the floor slab in a symmetrical manner. The rotary ejector assembly abuts against the first edge-sealing side plate or the second edge-sealing side plate.

[0019] Furthermore, the rotary ejector assembly includes a sleeve and an ejector; The top end of the sleeve is fixedly arranged on the lower end surface of the floor slab; A horizontal track groove is provided on the side wall of the sleeve; The rotating shaft protruding from the end of the ejector pin is arranged in the sleeve, and the other end passes through the sleeve from the horizontal track groove; The horizontal track groove serves as a guide and limit for the horizontal rotation of the ejector pin.

[0020] Furthermore, a sinking groove is provided at one end of the horizontal track groove close to the I-beam, and when the ejector pin is rotated to point to one side of the I-beam, it sinks into the sinking groove, thereby temporarily limiting the ejector pin.

[0021] Furthermore, an anchor plate is fixedly provided on the top end of the casing; Anchor bars are fixedly arranged on the anchor plate; The anchor bars are anchored in the floor slab, so that the sleeve is fixedly connected to the floor slab.

[0022] Compared with the prior art, this application has the following beneficial effects: (1) Light weight, high strength, good ductility and excellent seismic performance; (2) Compared with traditional steel frame beams, this application solves the corrosion and fire prevention problems of components, has excellent durability and fire resistance, eliminates the need for fire retardant paint and anti-corrosion coating, has low subsequent maintenance costs, and has good economic efficiency; (3) Compared with traditional cast-in-place reinforced concrete beams and steel-concrete beams, the present invention adopts factory prefabrication and on-site assembly, which reduces the amount of wet work on site, has a fast construction speed, high installation accuracy, shortens the construction period, and avoids the construction progress and construction quality being affected by the environment and season.

[0023] (4) Compared with the prefabricated partially encapsulated steel-concrete composite beam (PEC beam), this application solves the problem of layout and maintenance of pipelines inside the beam body. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 This is a schematic diagram of the planar structure of the maintenance-free steel frame beam disclosed in this application; Figure 2 Schematic diagram of the planar structure of the outer plate; Figure 3 It is a schematic diagram of the planar structure of the connection between the outer plate and the hanger; Figure 4 This is a structural diagram of the inspection port; Figure 5 Schematic diagram of the structure of the stiffeners and aerated blocks of the maintenance-free steel frame beam; Figure 6 for Figure 5 Cross-sectional view at 1-1; Figure 7 for Figure 5 Cross-sectional view at 2-2; Figure 8This is a schematic diagram of the plan structure of a maintenance-free steel frame beam with hinges before installation; Figure 9 for Figure 8 A partial enlarged view of point A in the middle; Figure 10 This is a schematic diagram of the planar structure of the maintenance-free steel frame beam with hinges after installation; Figure 11 It is a schematic diagram of the planar structure of the rotary ejector assembly; Figure 12 It is a structural diagram of the horizontal track groove; Figure 13 This is a schematic diagram of the range of rotation of the ejector pin; Figure 14 This is a schematic diagram of the structure of the ejector pin supporting the outer plate from a top-down perspective; Figure 15 This is a cross-sectional view of the steel floor beam; Figure 16 This is a schematic diagram of steel bar arrangement; Figure 17 Schematic diagram of steel bar welding joint; Figure 18 It is a calculation diagram; Figure 19 This is a schematic diagram of the shear span division of continuous beams; Figure 20 This is a schematic diagram of the concrete surrounding the square steel tube; Figure 21 This is a structural diagram of the cracking of the concrete cover; Figure 22 This is a schematic diagram of pull-off failure; Figure 23 Schematic diagram of shear failure; Figure 24 Calculation diagram for minimum stirrup ratio Figure 25 Detailed flow chart of the design method for Example 5.

[0026] Reference numerals: 1-External plate; 2-Hanging seat; 3-H-shaped steel beam; 4-Stud; 5-Floor slab; 6-First side slab; 7-Second side slab; 8-Bottom slab; 9-First side slab concrete layer; 10-First side slab steel mesh; 11-Second side slab concrete layer; 12-Second side slab steel mesh; 13-Bottom slab concrete; 14-Bottom slab steel mesh; 15-Factory prefabrication section; 16-Factory casting section; 17-Vertical section; 18-Horizontal section; 19-Welding material; 20-Inspection port; 21-Aerated block; 22-Stiffening rib; 23-First hinge; 24-Second Hinge; 25-first angle steel holder; 26-second angle steel holder; 27-first edge banding plate; 28-second edge banding plate; 29-first edge banding top plate; 30-first edge banding side plate; 31-second edge banding top plate; 32-second edge banding side plate; 33-rotating ejector assembly; 34-sleeve; 35-thimble; 36-horizontal track groove; 37-rotating axis; 38-sinking groove; 39-anchor plate; 40-anchor bar; 41-fireproof edge banding layer; 42-transverse frame bar; 43-rectangular tube; 44-rebar; 45-post-cast concrete layer; 46-rivet. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0030] It should also be noted that the following specific embodiments or specific implementations are a series of optimized settings listed in the present invention to further explain the specific content of the invention, and these settings can be combined or used in association with each other.

[0031] The present invention will be further explained below with reference to specific embodiments.

[0032] Example 1 like Figure 1 As shown, a maintenance-free steel frame beam provided in this embodiment includes an outer plate 1, a hanger 2 and an H-shaped steel beam 3; The floor slab 5 is supported by the H-shaped steel beam 3 , and studs 4 are welded on the H-shaped steel beam 3 to strengthen the connection between the H-shaped steel beam 3 and the floor slab 5 ; The hanger 2 is fixedly arranged on the upper flange of the H-shaped steel beam 3; The hanging seat 2 is connected to the outer plate body 1 .

[0033] As a further implementation of this embodiment, the outer plate body 1 is a U-shaped cross-section structure, including a first side plate 6, a second side plate 7 and a bottom plate 8; The top ends of the first side panel 6 and the second side panel 7 are connected to the hanging seat 2 .

[0034] As a further implementation of this embodiment, the first side panel 6 includes a first side panel concrete layer 9 and a first side panel steel mesh 10; The second side panel 7 includes a second side panel concrete layer 11 and a second side panel steel mesh 12; The bottom plate 8 includes bottom plate concrete 13 and bottom plate steel mesh 14; The first side plate steel mesh 10 , the second side plate steel mesh 12 and the bottom plate steel mesh 14 are respectively embedded in the first side plate concrete layer 9 , the second side plate concrete layer 11 and the bottom plate concrete 13 .

[0035] The concrete layer thickness in this embodiment is between 50mm and 70mm, and the concrete strength grade is C20-C30. The steel mesh is a shaped welded mesh with a steel bar diameter of 5mm-8mm and a transverse and longitudinal spacing of no more than 150mm. The steel mesh of the hanger 2 provides a support, with a limb length of no less than 30mm and the limb tip not protruding from the concrete outer layer. The wall thickness of the angle steel must meet the load-bearing capacity calculation required to resist the self-weight of the detachable outer layer assembly and must be no less than 4mm. The angle steel hanger 2 and its weld with the steel beam must meet the load-bearing capacity calculation required to resist the self-weight of the detachable outer layer assembly.

[0036] like Figure 2As shown, as a further implementation of this embodiment, the first side panel 6, the second side panel 7 and the bottom panel 8 are an integrated structure; The first side slab concrete layer 9 and the second side slab concrete layer 11 include a factory prefabricated portion 15 and a factory cast portion 16; The factory prefabricated part 15 is integrally cast with the bottom slab concrete 13; The factory casting part 16 wraps the upper ends of the first side plate steel mesh 10 and the second side plate steel mesh 12; The factory casting portion 16 is cast after the upper ends of the first side plate steel mesh 10 and the second side plate steel mesh 12 are connected to the hanging seat 2 .

[0037] like Figure 3 As shown, as a further implementation of this embodiment, the hanging seat 2 is an L-shaped structure, including a vertical portion 17 and a horizontal portion 18; The upper end of the vertical portion 17 is welded to the lower end surface of the upper flange of the H-shaped steel beam 3; The lower end of the vertical portion 17 is integrally connected to one end of the horizontal portion 18; The horizontal portion 18 is provided with a through hole for the steel bar head at the end of the steel mesh to pass through; After the steel bar head passes through the horizontal portion 18 , the lower end surface of the horizontal portion 18 abuts against the upper end surface of the factory-prefabricated portion 15 , and the steel bar head and the horizontal portion 18 are welded together by welding material 19 .

[0038] like Figure 4 As shown, as a further implementation of this embodiment, an inspection opening 20 is opened on the first side panel 6 and the second side panel 7, and a fireproof panel is detachably provided on the inspection opening 20.

[0039] Inspection opening 20 is rectangular and is used for inspecting internal pipelines. Its height should not exceed 0.6 times the height of the H-beam 3, and its width should not exceed the height of the H-beam 3. The clearance between openings along the length of the H-beam 3 should not be less than the opening width, and the height difference between the top of the opening and the top of the H-beam 3 should not be less than 0.25 times the height of the H-beam 3. Pipeline inspection opening 20 is normally sealed with fireproof panels and opened for inspection.

[0040] The implementation of this embodiment is divided into two stages, namely the following steps: S1: prefabrication stage; S2: Construction phase.

[0041] Step S1 is specifically as follows: S11: Determine the size and spacing of the steel bar reserved holes for the outer layer angle steel hanger 2 branches based on the steel bar spacing and diameter of the steel mesh, and drill holes in the angle steel branches; S12: Weld the outer cladding angle steel hanger 2 to the bottom surface of the upper flange of the H-shaped steel beam 3; S13: Processing the concrete outer cladding precast panels to form an integral whole with the steel mesh.

[0042] Step S2 is specifically as follows: S21: Complete the installation of steel beams; S22: Install the factory-prefabricated part 15. A gap of no less than 1 / 400 of the beam span must be left between the bottom of the factory-prefabricated part 15 and the lower flange of the steel beam. The steel bar heads at both ends of the factory-prefabricated part 15 pass through the outer cladding angle steel hanger 2 and are welded around the perimeter with fillet welds. S23: Concrete pouring of the factory pouring section 16 is completed.

[0043] By adopting the above technical solution, the present invention has the following beneficial effects: (1) The H-shaped steel beam 3 is fixed to the lower end surface of the floor slab 5 by means of bolts 4, providing stable support for the entire structure; the hanger 2 is connected to the H-shaped steel beam 3 and the outer plate 1, and the design of the hanger 2 steel mesh, the angle steel hanger 2 and the welds with the steel beam meet the bearing capacity requirements, ensuring that the various parts of the structure are firmly connected, thereby enhancing the stability and safety of the overall structure.

[0044] (2) The outer panel 1 adopts a U-shaped cross-section structure, and part of the structure is prefabricated. During the prefabrication stage, the concrete outer cladding prefabricated panels and the steel mesh can be processed in advance to form a whole. During the construction stage, only the steps of installing the steel beams, installing the factory prefabricated part 15, and pouring the concrete of the factory casting part 16 need to be completed, which reduces the workload and complexity of on-site construction, shortens the construction period, and improves construction efficiency.

[0045] (3) Clearly specify parameters such as the thickness of the concrete layer, strength grade, diameter of the steel bars of the steel mesh, and spacing, and use standardized welded mesh to ensure the quality stability and consistency of the components and reduce quality problems caused by construction errors.

[0046] (4) Inspection openings 20 are provided on the first side panel 6 and the second side panel 7, and fireproof panels are detachable to facilitate inspection of internal pipelines. The size and position of the inspection openings 20 are reasonably designed to meet the inspection requirements without affecting the overall performance of the structure, thereby reducing the difficulty and cost of subsequent maintenance.

[0047] (5) The first side plate 6, the second side plate 7 and the bottom plate 8 of the outer plate body 1 adopt an integrated structure. The factory prefabricated part 15 is cast integrally with the bottom plate concrete 13, and the factory cast part 16 wraps the upper end of the steel mesh. This design makes the structural connection tighter and enhances the integrity and waterproof performance of the structure; the hanger 2 is an L-shaped structure with a through hole, which is convenient for the steel bar head at the end of the steel mesh to pass through and be welded, making the connection more firm and reliable.

[0048] Example 2 This embodiment provides a maintenance-free steel frame beam that is a further improvement on the first embodiment. As in the first embodiment, the concrete layer thickness is between 50 mm and 70 mm, and the concrete strength grade is C20-C30. The steel mesh is a shaped welded mesh, with a steel bar diameter of 5 mm to 8 mm and a transverse and longitudinal spacing of no more than 150 mm.

[0049] like Figure 5 As shown, as a further implementation of this embodiment, an aerated block 21 is further provided between the outer plate body 1 and the H-shaped steel beam 3 to enhance the fire resistance of the prefabricated beam and provide a single-sided formwork for the casting of the first side panel 6 and the second side panel 7.

[0050] The aerated blocks 21 in this embodiment are arranged on both sides of the web of the H-shaped steel beam 3, which effectively enhances the fire resistance of the steel beam and provides a single-sided template for the production of the concrete outer layer.

[0051] like Figure 5-7 As shown, as a further implementation of this embodiment, the H-shaped steel beam 3 is provided with a stiffening rib 22 for strengthening the torsional rigidity of the H-shaped steel beam 3 and dividing the aerated block 21 into a plurality of small blocks, so as to facilitate the installation of the aerated block 21; Ends of the reinforcing ribs 22 are inserted into the first side panel concrete layer 9 and the second side panel concrete layer 11 and are welded to the first side panel steel mesh 10 and the second side panel steel mesh 12 .

[0052] The stiffening ribs 22 can enhance the torsional rigidity of the H-shaped steel beam 3 and are used to fix the steel mesh. The thickness of the stiffening ribs 22 is equal to the web of the H-shaped steel beam 3. The spacing between the stiffening ribs 22 is a multiple of the steel bar spacing between 200mm and 400mm.

[0053] As a further implementation of this embodiment, a transverse reinforcement 42 is welded to the lower end of the H-shaped steel beam 3; The bottom plate steel mesh 14 is welded to the side of the transverse reinforcement 42 away from the H-shaped steel beam 3 .

[0054] The transverse reinforcement bars 42 are used to support the bottom plate reinforcement mesh 14, and have a diameter of 8-12 mm and a spacing of 300 mm-400 mm.

[0055] The above-mentioned parts of this embodiment can be processed and produced in the factory through the entire process, including the following steps: T1: Weld stiffening ribs 22 on both sides of the H-shaped steel beam 3 according to the designed spacing; T2: Weld transverse reinforcement 42 to the bottom surface of the lower flange of the H-shaped steel beam 3; T3: Fill the two side grids formed by the web, flange and stiffener 22 of the steel beam with aerated blocks 21; T4: Weld the intersection of the steel mesh and the stiffening rib 22, with the bottom of the steel mesh close to the horizontal reinforcement; T5: Formwork and pouring of concrete outer cladding.

[0056] By adopting the above technical solution, the present invention has the following beneficial effects: (1) Aeration blocks 21 are set on both sides of the web of the H-shaped steel beam 3, which effectively enhances the fire resistance of the entire prefabricated beam, provides protection for the safety of the structure in extreme conditions such as fire, and prolongs the durability of the structure in high temperature environments.

[0057] (2) The aerated block 21 not only plays a role in fire resistance, but also provides a single-sided formwork for the casting of the first side panel 6 and the second side panel 7, reducing the use of formwork and the installation process, thereby reducing construction costs and difficulty. At the same time, the stiffening ribs 22 divide the aerated block 21 into multiple small blocks, facilitating the installation of the aerated block 21 and improving construction efficiency.

[0058] (3) The stiffening ribs 22 provided on the H-shaped steel beam 3 enhance the torsional rigidity of the steel beam, making the structure more stable when subjected to complex loads such as torque; the ends of the stiffening ribs 22 are inserted into the concrete layer and welded to the steel mesh, and the bottom plate steel mesh 14 is welded to the transverse frame bars 42, thereby enhancing the connection strength between the steel mesh and the steel beam and improving the integrity and stability of the entire prefabricated beam structure.

[0059] Example 3 This embodiment provides a maintenance-free steel frame beam that is a further improvement on the first embodiment. As in the first embodiment, the concrete layer thickness is between 50 mm and 70 mm, and the concrete strength grade is C20-C30. The steel mesh is a shaped welded mesh, with a steel bar diameter of 5 mm to 8 mm and a transverse and longitudinal spacing of no more than 150 mm.

[0060] like Figure 8-10 As shown as a further implementation of this embodiment, the first side panel 6 and the bottom panel 8 are rotatably connected via a first hinge 23; The second side panel 7 and the bottom panel 8 are rotatably connected via a second hinge 24 .

[0061] As a further implementation of this embodiment, one end of the first hinge 23 is fixedly connected to the first side plate steel mesh 10, and the other end is fixedly connected to the bottom plate steel mesh 14; One end of the second hinge 24 is fixedly connected to the second side plate steel mesh 12 , and the other end is fixedly connected to the bottom plate steel mesh 14 .

[0062] As a further implementation of this embodiment, a first angle steel holder 25 is fixedly provided at one end of the first side plate steel mesh 10 away from the first hinge 23; A second angle steel holder 26 is fixedly provided on one end of the second side plate steel mesh 12 away from the second hinge 24; The first angle steel holder 25 and the second angle steel holder 26 are placed on the hanging seat 2 .

[0063] As a further implementation of this embodiment, a first edge sealing plate 27 is fixedly provided at one end of the first side plate steel mesh 10 away from the first hinge 23; A second edge sealing plate 28 is fixedly provided on one end of the second side plate steel mesh 12 away from the second hinge 24; The first edge sealing plate 27 and the second edge sealing plate 28 are L-shaped and are respectively arranged at the outermost ends of the first side plate 6 and the second side plate 7 .

[0064] The first and second edge sealing panels 27, 28 protect the upper edge of the outer cladding concrete from damage or wear during loading and unloading. They also prevent the rotating ejector pins 35 from directly contacting the outer cladding concrete, potentially causing localized breakage and dusting. The thickness of the first and second edge sealing panels 27, 28 ranges from 2 mm to 6 mm.

[0065] As a further implementation of this embodiment, the first edge-sealing plate 27 includes a first edge-sealing top plate 29 and a first edge-sealing side plate 30; The first edge sealing top plate 29 is provided to protect the upper edge of the first side plate concrete layer 9 from collision damage or wear during loading and unloading; The first edge-sealed side plate 30 is exposed on the outward side of the first side plate concrete layer 9; The second edge-sealing plate 28 includes a second edge-sealing top plate 31 and a second edge-sealing side plate 32; The second edge sealing top plate 31 is provided to protect the upper edge of the second side plate concrete layer 11 from collision damage or wear during loading and unloading; The second edge-sealed side plate 32 is exposed on the outward side of the second side plate concrete layer 11 .

[0066] The first and second side panels 30, 32 prevent the outer cladding from separating from the concrete and protect the concrete from damage or wear when it contacts the ejector pins 35. The first and second side panels 30, 32 are secured to the concrete using steel bars with a diameter of 5mm-8mm. The length and width of the first and second side panels 30, 32 should be no less than 0.5 times their thickness.

[0067] like Figure 11-14 As shown, as a further implementation of this embodiment, it also includes a rotating ejector assembly 33; The rotating ejector assembly 33 is provided with a plurality of symmetrical portions on the lower end surface of the floor 5; The rotating ejector assembly 33 abuts against the first edge-sealing side plate 30 or the second edge-sealing side plate 32 .

[0068] As a further implementation of this embodiment, the rotating ejector assembly 33 includes a sleeve 34 and an ejector 35; The top end of the sleeve 34 is fixedly arranged on the lower end surface of the floor slab 5; A horizontal track groove 36 is provided on the side wall of the sleeve 34; The rotating shaft 37 protruding from the end of the ejector pin 35 is disposed in the sleeve 34 , and the other end passes through the sleeve 34 from the horizontal track groove 36 ; The horizontal track groove 36 serves as a guide and limit for the horizontal rotation of the ejector pin 35 .

[0069] As a further implementation of this embodiment, a sinking groove 38 is provided at one end of the horizontal track groove 36 near the I-beam. When the ejector pin 35 rotates to point to one side of the I-beam, it sinks into the sinking groove 38, which temporarily limits the ejector pin 35.

[0070] The ejector pin 35 rotates within the horizontal guide rail between 0 and 90 degrees, with 0 degrees being perpendicular to the outer cladding edge banding and 90 degrees being parallel to the outer cladding edge banding. The horizontal track bends downward at 0 degrees, and when the ejector pin 35 rotates to this position, it falls into a sunken groove 38 within the track and stops rotating. Preferably, the depth of the sunken groove 38 is no less than 0.75 times the diameter of the ejector pin 35. The diameter of the ejector pin 35 is 4-10 mm, and the diameter of the rotating shaft 37 is no less than 1.2 times the diameter of the rotating ejector pin 35. The sleeve wall thickness is no less than 0.2 times the diameter of the rotating shaft 37 and no less than 1 mm. The width of the horizontal track is 1-2 mm larger than the diameter of the ejector pin 35.

[0071] As a further implementation of this embodiment, an anchor plate 39 is fixedly provided on the top end of the sleeve 34; An anchor bar 40 is fixedly provided on the anchor plate 39; The anchor bars 40 are anchored in the floor slab 5 , so that the sleeve 34 is fixedly connected to the floor slab 5 .

[0072] Anchor plate 39 is a square or circular plate with a thickness of at least 4 mm. The side length or diameter of anchor plate 39 is 50 mm larger than the outer diameter of rotating sleeve 34. Sleeve 34 is centrally welded to anchor plate 39. While ejector pins 35 provide support for the outer cladding side panels, anchor bars 40 primarily bear shear forces. Anchor bars 40 are constructed of C6-C10 steel, and their anchorage length is at least 0.5 times the thickness of anchor plate 39. Rotating ejector pin assemblies 33 are evenly spaced along the length of the beam on both sides of the beam. The spacing between ejector pins 35 should not exceed 500 mm.

[0073] As a further implementation of this embodiment, after the outer panel 1 is installed on the hanger 2 , the exposed portions of the first hinge 23 and the second hinge 24 are sealed with fireproof material to form a fireproof edge sealing layer 41 .

[0074] The specific implementation process of this embodiment includes the following steps: X1: factory prefabrication stage; X2: On-site installation phase.

[0075] As a further implementation of this embodiment, the step X1 is specifically as follows: X11: Prefabricated outer panel 1; X12: Prefabricated H-shaped steel beam 3; X13: Prefabricated rotating ejector pin assembly 33.

[0076] As a further implementation of this embodiment, the step X11 is specifically as follows: X111: Weld the fixings to the outer cladding edge banding; X112: Weld the outer cladding angle steel holder to the steel mesh; X113: One end of the steel mesh is welded to the outer cladding edge plate, and the other end is welded to the stainless steel hinge; X114: Outer cladding bottom plate steel mesh 14 is welded to the stainless steel hinge; X115: Make a concrete formwork box according to the dimensions of the outer cladding side panels and the outer cladding bottom panel 8; X116: Place the connection between the edge banding, steel mesh and stainless steel hinge into the formwork box and pour concrete.

[0077] As a further implementation of this embodiment, the step X12 is specifically as follows: X121: Weld stud 4 to the top surface of the upper flange of H-beam 3; X122: The bottom surface of the upper flange of the H-shaped steel beam 3 is welded with an angle steel hanger 2.

[0078] As a further implementation of this embodiment, the step X13 is specifically as follows: X131: The ejector pin 35, the rotating shaft 37 and the rotating shaft 37 sleeve 34 with the rotating ejector pin 35 track are integrally formed; X132: Weld the anchor bar 40 to the anchor plate 39; X133: Weld the sleeve 34 to the anchor plate 39.

[0079] As a further implementation of this embodiment, the step X2 is specifically as follows: X21: Complete the assembly of prefabricated steel beam components and frame columns; X22: During the process of supporting the formwork and tying the reinforcement for floor slab 5, the rotating ejector assembly 33 is positioned and placed, and floor slab 5 is poured. After the main structure construction is finally completed, the removable outer cladding assembly is installed; X23: Move ejector pin 35 to a 90-degree angle; X24: Hang the two first side panels 6 and the second side panel 7 of the outer panel 1 to the hanging seat 2; X25: Move the ejector pin 35 to the 0 degree direction. The ejector pin 35 then falls into the sinking groove 38, and the needle tip contacts the edge banding of the outer cladding side panel. X26: At the intersection of the first side panel 6, the second side panel 7 and the bottom panel 8, use fire retardant paint to seal the edges to complete the installation work.

[0080] By adopting the above technical solution, the present invention has the following beneficial effects: (1) The first side panel 6 and the bottom panel 8, as well as the second side panel 7 and the bottom panel 8, are rotatably connected by hinges. This design makes the installation and disassembly process of the outer panel body 1 simpler and more flexible, reduces the installation difficulty and time cost, and improves the construction efficiency.

[0081] (2) The hinges are fixedly connected to the side panels and bottom plate steel mesh 14, and the angle steel holders are placed on the hangers 2. The combination of multiple connection methods enhances the connection strength between the various parts of the outer panel 1 and between the outer panel 1 and the hangers 2, ensuring the overall stability and safety of the structure.

[0082] (3) The setting of the L-shaped edge banding effectively protects the upper edge concrete of the outer cladding side panel from collision damage or wear during loading and unloading, and prevents the rotating ejector 35 from directly contacting the concrete and causing local damage and dust falling, thereby extending the service life of the concrete structure and reducing the subsequent maintenance cost.

[0083] (4) The rotating ejector assembly 33 realizes the horizontal rotation and temporary limit function of the ejector 35 through the design of the sleeve 34, ejector 35, horizontal track groove 36 and sinking groove 38. The ejector 35 can rotate within the range of 0-90 degrees, and the sinking groove 38 temporarily fixes the ejector 35, facilitating the installation and positioning of the outer panel 1 and improving the accuracy and convenience of construction.

[0084] (5) The sleeve 34 is fixedly connected to the floor slab 5 through the anchor plate 39 and the anchor bar 40. The dimensions of the anchor plate 39 and the anchor bar 40 are reasonably designed to withstand the supporting force generated by the ejector pin 35 on the outer cladding side plate, ensuring that the rotating ejector pin assembly 33 is firmly connected to the floor slab 5, providing reliable support for the entire structure.

[0085] (6) After the outer panel 1 is installed, the exposed part of the hinge is sealed with fireproof material to form a fireproof edge sealing layer 41, which enhances the fireproof performance of the prefabricated beam and improves the safety of the structure in emergency situations such as fire, thus buying more time for personnel evacuation and property protection.

[0086] Example 4 like Figure 15 As shown, this embodiment provides a steel floor beam including a rectangular tube 43; The side wall of the rectangular tube 43 is provided with steel bars 44; The rectangular tube 43 is wrapped in a post-cast concrete layer 45; The post-cast concrete layer 45 is disposed below the floor slab and hides the rectangular tube 43 .

[0087] As a further implementation of this embodiment, the steel bars 44 are arranged on the side wall of one side or on the side walls of multiple sides of the rectangular tube 43 .

[0088] Optionally, rivets 46 are provided on the outer side wall of the rectangular tube 43 where no steel bars 44 are provided, for anchoring with the post-cast concrete layer 45 .

[0089] The steel floor beams disclosed in this embodiment can be independent structures. The rectangular tubes 43 can be filled with concrete or other materials as needed. They can also be used to realize the function of a micro-pipeline corridor. Where necessary, pipeline inspection ports can be opened under the steel beams for inspection. In addition, the outer panels of Examples 1-3 can also be sheathed in the rectangular tubes 43. In this embodiment, the concrete strength is preferably C30, and is anchored to the post-cast concrete layer 45 by rivets 46, and coordinated with the post-cast concrete layer 45 by steel bars 44. It is necessary to control the spacing of the steel bars 44 and avoid the concrete from being damaged first. The calculation method should meet the calculation requirements.

[0090] By adopting the above technical solution, the present invention has the following beneficial effects: (1) Steel bars 44 are provided on the side walls of the rectangular tube 43 and can be arranged on multiple sides, which can enhance the ability to work in coordination with the post-cast concrete layer 45 and make the overall structure more stable. The outer side walls without steel bars 44 are anchored to the post-cast concrete layer 45 with rivets 46, which further improves the reliability of the connection.

[0091] (2) The post-cast concrete layer 45 is set under the floor slab and hides the rectangular tube 43, making the building appearance neater and more beautiful. At the same time, it protects the rectangular tube 43, reduces the erosion and damage to it by external factors, and prolongs its service life.

[0092] Example 5 like Figure 25 As shown, this embodiment provides a method for calculating the steel bar spacing and concrete thickness in Example 4, and the specific calculation method is as follows.

[0093] 1. Calculation method of steel bar spacing.

[0094] The steel bars are HRB400 steel bars with a diameter of 10mm and are welded with double-sided fillet welds along the entire length of the steel beam (assuming an arc strike plate is used); the floor slabs are made of C30 concrete, the box beams are made of Q355 steel, and the welding rods are E50. The steel box beam and steel bar layout are as follows Figure 16 As shown in the figure, the calculated shear force transfer direction is along the steel box girder.

[0095] 1. Steel bar weld size Article 4.5.12 of JGJ 18-2012 "Rebar Welding and Acceptance Regulations" stipulates that when lap welding steel bars and steel plates, the welded joints (such as Figure 17 The following provisions shall be met: 1) The lap length of HPB 300 steel bars shall not be less than 4 times the steel bar diameter, and the lap length of other grades of steel bars shall not be less than 5 times the steel bar diameter; 2) The weld width shall not be less than 60% of the steel bar diameter, and the effective weld thickness shall not be less than 35% of the steel bar diameter.

[0096] like Figure 17 As shown in the figure, the meaning of each symbol is: d-steel diameter; l-lap length; b-weld width; S-effective weld thickness.

[0097] According to the above requirements, if Figure 18 As shown, the weld width b is 60% of the rebar diameter, which is 6mm. According to the Pythagorean theorem, c = 3.3mm, and the weld thickness s = 4.5mm, which is greater than 35% of the rebar diameter = 3.5mm. The weld leg height on one side of the steel plate is h = d / 2 + c = 8.3mm.

[0098] The bearing capacity N of a single fillet weld is:

[0099] Where: β is the strength increase factor of the front fillet weld. For structures subjected to static loads and indirectly subjected to dynamic loads, β = 1.22; f wf is the strength design value of the fillet weld; he is the calculated thickness of the right-angle fillet weld (mm); l w is the calculated length of the fillet weld.

[0100] 2. Concrete bearing capacity Concrete is locally under pressure. Refer to GB / T50010 2011 "Concrete Structure Design Standard" Article 6.6.1 for calculation. Concrete is locally under pressure F L :

[0101] Where: c is the concrete strength influence coefficient, which is 1.0 here; β l is the strength enhancement factor of concrete when subjected to local compression, which is 1.73 according to 6.6.2; f c is the design value of the concrete axial compressive strength, which is 14.3N / mm2 at C30; A ln It is the net local compressive area of ​​concrete.

[0102] 3. Spacing arrangement Article 12.2.3 of JGJ 138-2016 "Code for Design of Composite Structures" stipulates that the shear connectors between the concrete flange and the steel beam of a fully shear-connected composite beam shall comply with the following formula:

[0103] Where n is the number of shear connectors in a shear span of a fully shear-connected composite beam.

[0104] is the longitudinal shear capacity of a shear connector, calculated as the smaller of the steel and concrete capacities.

[0105] V s The longitudinal shear force at the interface between the steel beam and the concrete flange in each shear span is calculated as follows: like Figure 19 As shown, the longitudinal shear force at the interface between the steel beam and the concrete wing plate should be divided into several shear spans with the point of maximum absolute value of the bending moment and the support as the boundary. The longitudinal shear force of each shear span should be calculated according to the following formula.

[0106] 1) The section from the point with the maximum positive bending moment to the edge support, i.e. the m1 section: V s = min{A a f a , f c b e hc1} 2 Section from the maximum positive bending moment point to the middle support (maximum negative bending moment point), i.e., sections m2 and m3: V s = min{A a f a , f c b e h c1}+ A ' s f y Among them: A a ——Cross-sectional area of ​​steel beam; f a is the design value of the compressive and tensile strength of the steel beam, which is taken as 305 N / mm2 here; f c is the design value of the concrete axial compressive strength, which is 14.3N / mm2 at C30; h c1 is the thickness of the concrete wing plate, ignoring the height of the support plate and the corrugated steel plate rib, which is 40mm here; A ’ s is the cross-sectional area of ​​the longitudinal reinforcement within the effective width of the concrete flange in the negative bending moment zone; f y is the design value of steel bar tensile strength, here it is 360N / mm2; b e is the effective width of the composite beam concrete flange, and its calculation formula is as follows: b e =b0+b1+b2 Where: b0 is the width of the top of the plate support. When the plate support angle α is less than 45 degrees, the width of the top of the plate support should be calculated as α = 45 degrees; when there is no plate support, the width of the upper flange of the steel beam is used; b1 and b2 are the calculated widths of the flanges on the outside and inside of the beam, and the equivalent span of the beam is l e b1 should not exceed the actual overhang width S1 of the flange; b2 should not exceed the net distance S between the upper flanges of adjacent steel beams or plate supports. o 1 / 2; l e For the equivalent span, for simply supported composite beams, it is taken as the span l of the simply supported composite beam; for continuous composite beams, the positive bending moment zone of the middle span is taken as 0.6l, the positive bending moment zone of the side span is taken as 0.8l, and the negative bending moment zone of the support is taken as 0.2 times the sum of the spans of the two adjacent spans.

[0107] After calculating the equivalent span according to the actual situation, calculate the above formula to get the calculation result of the steel bar spacing.

[0108] 2. Design method of concrete thickness 1. Concrete instability and failure When the thickness of the outer concrete is thin, instability is likely to occur. Concrete instability failure mainly occurs when the cross-section of the steel pipe is square, such as Figure 20 shown.

[0109] When the effect of stirrups is ignored, the concrete surrounding the steel tube can be simplified as a rectangular thin plate with a height of H, a width of D, a thickness of C, three simply supported sides and one free side. The critical elastic-plastic stress of concrete instability is:

[0110] Where: C is the thickness of concrete, mm; D is the width of the steel pipe, mm; K is the stability coefficient of the plate. When the plate boundary is fixed on two sides, one side is simply supported and the other side is free, k=3.65+2.83(D / H)2; H is the height of the board, mm; Ec is the elastic modulus of concrete, 30000 MPa; V is the Poisson's ratio of concrete, which is taken as 0.2; η is the elastic-plastic buckling coefficient, η=Et / Ec; Et is the tangent modulus of concrete. According to the elastic buckling theory, considering the elastic-plastic properties of concrete, the tangent modulus of concrete is taken as 7 MPa.

[0111] In order to ensure that the concrete does not become unstable before reaching the ultimate compressive strength, the critical stress σ cr Should be greater than the axial compressive strength of concrete f c =14.3MPa. When the two are equal, the ratio of critical protective layer thickness to steel pipe diameter can be obtained:

[0112] 2. Concrete cracking and damage like Figure 21 As shown, when the concrete cover is thin, it is prone to cracking, affecting the combined interaction between steel and concrete. The critical value of the concrete cover can be determined from the perspective of concrete cracking. The calculation assumes that the effect of stirrups is ignored before cracking and that the interaction between the steel tube and concrete is uniformly distributed. For square steel tubes, it is assumed that the concrete cracks along the 45° angle of the tube edge. Concrete cover cracking can be categorized into two failure modes: tensile and shear, which will be considered separately below.

[0113] 2.1 Pull-off failure Depend on Figure 22 As shown, the static equilibrium can be obtained:

[0114] Where, φ is the stress unevenness coefficient; q is the extrusion stress between concrete and steel pipe; f t is the tensile strength of concrete; D is the diameter or width of the steel pipe; C is the thickness of the concrete cover. hf Therefore, when the compressive stress q between concrete and steel pipe takes the local maximum bond stress τ hf When , C has a critical value:

[0115]

[0116]

[0117] Where, f c ’ is the compressive strength of the cylinder. Based on the above, the critical protective layer thickness for tensile damage can be obtained as follows:

[0118] 2.2 Shear failure Shear failure diagram Figure 23 shown.

[0119] From static equilibrium, we can get

[0120] Where fτ is the shear strength of concrete. When the compressive stress q between concrete and steel pipe takes the local maximum bond stress τhf, C has a critical value:

[0121]

[0122] In summary, the critical protective layer thickness for shear failure can be obtained:

[0123] 3. Minimum stirrup ratio Elastic-plastic instability of comprehensive protective layer C cr1 , pull off failure C cr2 and shear failure C cr3 The larger of the three cases is taken as the critical concrete cover thickness. After concrete cracking, sufficient stirrups can effectively prevent concrete spalling. The concrete cracking forms are shown in the figure below. One is cracking at a 45-degree angle along the edge of the steel section, and the other is cracking outward along the surface of the steel section. The stirrup ratio can be calculated based on the force balance condition:

[0124]

[0125] Where n is the number of stirrups; A sv is the cross-sectional area of ​​the stirrup; B is the cross-sectional width; s is the stirrup spacing; f yv is the yield strength of stirrups; f t is the tensile strength of concrete; C is the thickness of concrete. The minimum stirrup ratio requirement is as follows: Figure 24 shown.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A maintenance-free steel frame beam, characterized in that: Including outer plate, hanger and H-shaped steel beam; The hanger is fixedly arranged on the upper flange of the H-shaped steel beam; The hanging seat is connected to the outer plate; The outer plate body is a U-shaped cross-section structure, including a first side plate, a second side plate and a bottom plate; The top ends of the first side panel and the second side panel are connected to the hanging seat; The first side panel comprises a first side panel concrete layer and a first side panel steel mesh; The second side panel comprises a second side panel concrete layer and a second side panel steel mesh; The bottom plate includes bottom plate concrete and bottom plate steel mesh; The first side plate steel mesh, the second side plate steel mesh and the bottom plate steel mesh are respectively embedded in the first side plate concrete layer, the second side plate concrete layer and the bottom plate concrete.

2. The maintenance-free steel frame beam according to claim 1, characterized in that The first side panel, the second side panel and the bottom panel are an integrated structure; The first side slab concrete layer and the second side slab concrete layer include a factory prefabricated portion and a factory cast portion; The factory prefabricated part is integrally cast with the base plate concrete; The factory casting part wraps the upper ends of the first side plate steel mesh and the second side plate steel mesh; The factory casting portion is cast after the upper ends of the first side plate steel mesh and the second side plate steel mesh are connected to the hanging seat.

3. The maintenance-free steel frame beam according to claim 2, characterized in that The hanger is an L-shaped structure, comprising a vertical portion and a horizontal portion; The upper end of the vertical portion is welded to the lower end surface of the upper flange of the H-shaped steel beam; The lower end of the vertical portion is integrally connected to one end of the horizontal portion; The horizontal portion is provided with a through hole for the steel bar head at the end of the steel mesh to pass through; After the steel bar head passes through the horizontal portion, the lower end surface of the horizontal portion abuts against the upper end surface of the factory prefabricated portion, and the steel bar head and the horizontal portion are welded together using welding materials.

4. The maintenance-free steel frame beam according to claim 1, characterized in that Inspection openings are provided on the first side panel and the second side panel, and fireproof panels are detachably provided on the inspection openings; An aerated block is further provided between the outer plate and the H-shaped steel beam to enhance the fire resistance of the precast beam and provide a single-sided formwork for the casting of the first side plate and the second side plate; The H-shaped steel beam is provided with stiffening ribs for strengthening the torsional rigidity of the H-shaped steel beam and dividing the aerated block into a plurality of small blocks, so as to facilitate the installation of the aerated block; Ends of the reinforcing ribs are inserted into the first side panel concrete layer and the second side panel concrete layer and are welded to the first side panel steel mesh and the second side panel steel mesh.

5. The maintenance-free steel frame beam according to claim 1, characterized in that The first side panel and the bottom panel are rotatably connected via a first hinge; The second side panel and the bottom panel are rotatably connected via a second hinge; One end of the first hinge is fixedly connected to the first side plate steel mesh, and the other end is fixedly connected to the bottom plate steel mesh; One end of the second hinge is fixedly connected to the second side plate steel mesh, and the other end is fixedly connected to the bottom plate steel mesh.

6. The maintenance-free steel frame beam according to claim 5, characterized in that A first angle steel holder is fixedly provided on one end of the first side plate steel mesh away from the first hinge; A second angle steel holder is fixedly provided on one end of the second side plate steel mesh away from the second hinge; The first angle steel holder and the second angle steel holder are placed on the hanging seat.

7. The maintenance-free steel frame beam according to claim 5, characterized in that A first edge sealing plate is fixedly provided on one end of the first side plate steel mesh away from the first hinge; A second edge-sealing plate is fixedly provided on one end of the second side plate steel mesh away from the second hinge; The first edge sealing plate and the second edge sealing plate are L-shaped and are respectively arranged at the outermost ends of the first side plate and the second side plate; The first edge-sealing plate includes a first edge-sealing top plate and a first edge-sealing side plate; The first edge-sealed top plate is configured to protect the upper edge of the first side plate concrete layer from collision damage or wear during loading and unloading; The first edge-sealed side plate is exposed on the outward side of the concrete layer of the first side plate; The second edge-sealing plate includes a second edge-sealing top plate and a second edge-sealing side plate; The second edge-sealed top plate is provided to protect the upper edge of the second side plate concrete layer from collision damage or wear during loading and unloading; The second edge-sealed side panel is exposed on the outward side of the concrete layer of the second side panel.

8. The maintenance-free steel frame beam according to claim 1, characterized in that Also included is a rotating ejector pin assembly; The rotating ejector pin assembly is provided in plurality on the lower end surface of the floor slab in a symmetrical manner. The rotary ejector assembly abuts against the first edge-sealing side plate or the second edge-sealing side plate; The rotary ejector assembly includes a sleeve and an ejector; The top end of the sleeve is fixedly arranged on the lower end surface of the floor slab; A horizontal track groove is provided on the side wall of the sleeve; The rotating shaft protruding from the end of the ejector pin is arranged in the sleeve, and the other end passes through the sleeve from the horizontal track groove; The horizontal track groove serves as a guide and limit for the horizontal rotation of the ejector pin.

9. The maintenance-free steel frame beam according to claim 8, characterized in that The horizontal track groove is provided with a sinking groove at one end close to the H-shaped steel beam. When the ejector pin is rotated to point to one side of the H-shaped steel beam, the ejector pin sinks into the sinking groove, thereby temporarily limiting the ejector pin.

10. The maintenance-free steel frame beam according to claim 8, characterized in that An anchor plate is fixedly provided on the top of the casing; Anchor bars are fixedly arranged on the anchor plate; The anchor bars are anchored in the floor slab, so that the sleeve is fixedly connected to the floor slab.

Images