A fireproof structure of steel-clad concrete beam with additional steel plate cavity and post-grouting method thereof

Abstract

The present invention discloses a fireproof structure of a steel-clad concrete beam with an additional steel plate cavity and a method thereof, comprising a structural beam-clad steel plate, an additional steel plate, stainless steel bolts, a rubber pad, a reserved steel pipe, cast-in-place concrete in the steel-clad beam, and a cement mortar layer. The beneficial effects of the present invention are as follows: the additional steel plate and the stressed trough steel are flexibly connected to form a whole, and can be hoisted as a whole with the trough steel; the additional steel plate and the stressed trough steel are flexibly connected, and the micro-deformation during the loading process of the steel-clad beam structure construction will not cause deformation of the cavity formed by the outer additional steel plate; the mortar layer formed by the additional cavity post-grouting can play the role of anti-corrosion, anti-rust and fire protection for the stressed trough steel, and has better stability and durability; and the later maintenance is simplified, and the maintenance cost is low.

Description

Technical Field

[0001] The invention relates to a comprehensive technology for corrosion, rust prevention, fire prevention and assembly of a steel-clad concrete beam structure, in particular to a steel-clad concrete beam with an additional steel plate cavity post-grouting fire prevention structure and a method thereof, and belongs to the technical field of construction engineering application. Background Art

[0002] In the existing construction process, on the basis of anti-corrosion and anti-rust treatment on the surface of the steel clad beam structure, thick fire-retardant coating is also applied to improve the fire resistance of the overall structure, or calcium silicate board and other plate-based fire-retardant materials are attached to the outside. However, the existing fire-proofing methods have the following problems in the construction of steel clad beam structures:

[0003] 1) Low assembly efficiency, because during the overall pouring process, the outer concrete channel steel has a large deformation. If the above method is done in advance, it will be damaged due to deformation. Therefore, the fireproof layer and the structural channel steel cannot be hoisted in advance. They can only be constructed twice after the structural construction is completed, which requires high-altitude work and low assembly degree;

[0004] 2) Thin coating fireproof materials are only used for fireproof requirements below level 2. The thick coating fireproof paint or calcium silicate fireproof board applied later can meet the level 1 fireproof requirements, but the surface appearance is not good. At the same time, it is easy to crack and fall off due to the stress deformation of the structure and fire baking. Therefore, the existing method has poor durability, there are safety risks when cracking and falling off at high altitude, and the fireproof performance is difficult to guarantee, so it should be used with caution for structures with level 1 fireproof level;

[0005] 3) Since there is no corresponding technology and acceptance standard for fire protection outside the steel clad beam structure, the specific use needs to be based on corresponding tests and expert demonstration;

[0006] 4) The existing fire prevention method is to carry out the conventional anti-corrosion and anti-rust measures on the outside of the beam-wrapped channel steel. The durability of the beam-wrapped channel steel mainly depends on the anti-corrosion and anti-rust performance. However, the durability of anti-corrosion and anti-rust materials is limited, generally less than ten years;

[0007] 5) Whether it is a thin or thick coating fireproof layer or a fireproof layer made of calcium silicate board or other adhesive panels, the durability is limited, generally less than 5 years. The later maintenance cost is high.

[0008] Based on this, the present application proposes a fire-proof structure of a steel-clad concrete beam with an additional steel plate cavity and a post-grouting method thereof. Summary of the invention

[0009] The purpose of the present invention is to provide a steel-clad concrete beam with an additional steel plate cavity post-grouting fireproof structure and a method thereof in order to solve the problem.

[0010] The present invention achieves the above-mentioned purpose through the following technical scheme: a steel-clad concrete beam with an additional steel plate cavity post-grouting fire-proof structure, comprising a structural beam-clad steel plate and an additional steel plate; the additional steel plate is arranged on the outside of the structural beam-clad steel plate, the structural beam-clad steel plate and the additional steel plate are connected by stainless steel bolts, the structural beam-clad steel plate is poured with cast-in-place concrete in the steel-clad beam, and the gap between the structural beam-clad steel plate and the additional steel plate is filled with a cement mortar layer with the same strength grade of the structural beam concrete.

[0011] As a further solution of the present invention: the additional steel plate is wrapped in a U-shape on the outside of the structural beam steel plate, and the thickness of the additional steel plate is 1 mm, and the outer wall of the additional steel plate is coated with anti-rust paint.

[0012] As a further solution of the present invention: the additional steel plate is provided with rubber pads at the joints of the beam ends and the beam top folding edges of the structural beam wrapping steel plate, and is edge sealed with flexible fireproof putty.

[0013] As a further solution of the present invention: a reserved steel pipe with an inner diameter of 15 mm is reserved along the beam side at the top of the closed cavity formed between the structural beam steel plate and the additional steel plate, and the reserved steel pipe spacing is ≤3m, and the protruding length from the floor is ≥50mm.

[0014] As a further solution of the present invention: both sides and the bottom of the structural beam-wrapping steel plate and the additional steel plate are flexibly connected by a plurality of stainless steel bolts.

[0015] As a further solution of the present invention: the cement mortar layer is a cement mortar protective layer with the same structural strength grade as the cast-in-place concrete.

[0016] A construction method for a steel-clad concrete beam with an additional steel plate cavity and post-grouting fireproof structure, the construction method comprising the following steps:

[0017] Step 1: Processing of the cavity steel plate of the steel clad beam: According to the size of the steel clad beam, the top and the beam end are retracted 2cm. Process the outer surface size of the cavity as the additional steel plate, and the folding edge of the beam top and the beam end is the same as the cavity thickness;

[0018] Step 2: Installation of cavity steel plates for steel clad beams with additional steel plates: Considering that the outer steel layer is easily damaged during transportation, on-site installation before lifting is preferred.

[0019] ① The M5 stainless steel bolts are used to connect the stress-bearing channel steel and the additional cavity steel plate, with a spacing of no more than 1m. They are evenly arranged along the outer steel of the structure, and can be staggered at the bottom of the beam. A bolt is set on the edge of the additional steel plate to ensure that the folded edge is tightly attached to the channel steel. The bolt hole position is designed in advance during steel plate processing, and the holes are punched in advance in the factory. During installation, according to the length of the outer steel of the structure, support overhead is added on site through the beam end and the beam. Then the additional steel plate is aligned and fixed with M5 bolts.

[0020] ② Measures to ensure the thickness of the cavity: Before installation, steel bar heads of equal length are processed in advance and spot welded on the surface of the channel steel with a spacing of no more than 50 cm. On the one hand, this ensures the thickness of the cavity and on the other hand, it serves to connect the post-injection mortar layer with the stressed channel steel.

[0021] ③ A 3mm thick and 2cm wide rubber pad is glued to the contact area between the additional steel plate folding edge and the corresponding stressed channel steel, and is tightened by bolts set along the folding edge to form a closed cavity to avoid leakage during the post-grouting process. Flexible fireproof putty is used to fully apply between the additional outer layer edge and the support end structure and the top plate structure;

[0022] Step 3: hoisting of the cavity of the steel clad beam with additional steel plate as a whole: after the cavity steel plate of the steel clad beam with additional steel plate is installed, it is hoisted as a whole with the outer steel of the structural beam and installed on the lattice column;

[0023] Step 4: Post-grouting of the steel plate cavity of the steel clad beam: After the structural concrete is poured and cured for more than seven days, post-grouting construction can be carried out.

[0024] The beneficial effects of the present invention are as follows: the fireproof structure of the steel ladle concrete beam with additional steel plate cavity and the method thereof are reasonably designed:

[0025] 1. The assembly efficiency is higher. The system can be installed in place at one time with the structure hoisting. Because bolt connection is adopted, the post-added steel plate and the structural beam-wrapping channel steel are not rigidly connected. During the concrete pouring process, the deformation of the channel steel caused by the gradually added structure and construction load has little effect on the additional steel plate and will not cause large warping deformation. Post-grouting is carried out on the floor, avoiding high-altitude operations, simple construction and good safety. Especially for structures with tight construction period and no need for ceiling decoration, the work efficiency is higher;

[0026] 2. Better fireproof performance. In terms of fireproof performance, this system not only has the mutual slow release of heat transfer and heat storage performance, but also has the protective function of the outer additional steel plate on the mortar layer. The outer additional steel plate is not a structural stress-bearing steel plate. As long as the structural stress-bearing steel plate has not lost its stress-bearing performance, the overall structure will deform less under the action of fire, so the outer additional steel plate will not lose its function due to the reduction of tensile properties after heating, unless it melts (the temperature of a fire generally varies according to different materials and environmental gases. Generally, the atmospheric environment of oils and fats is 200 to 300 degrees; the atmospheric environment of general building materials such as fibers is about 500 degrees; if it is a metal and oxygen-rich environment, it will reach 1300 degrees. The melting point of ordinary steel is about 1500℃, so in general fires, the melting point of steel is rarely reached), otherwise it will protect the internal mortar protective layer and delay its cracking and shedding time, thereby protecting the real stress-bearing concrete-wrapped channel steel, making the overall fireproof performance far better than reinforced concrete structures. The fire resistance of reinforced concrete structures can reach the first-level fire resistance standard, so the fire resistance of the steel plate cavity post-grouting steel clad beam system will be higher than the first-level fire resistance standard. According to different fire resistance limit requirements, a thicker post-grouting protective layer thickness and the thickness of the additional cavity steel plate can also be selected through experiments, which is conducive to the use of buildings with higher fire resistance limit requirements;

[0027] 3. The durability of the load-bearing structure is improved. This system adds a more effective mortar layer protection to the outer load-bearing channel steel, and obtains a functional protective layer that is both fireproof and rust-proof, similar to the steel bar protective layer in reinforced concrete structure. It blocks the contact between the load-bearing steel and the air, greatly improves the rust and corrosion resistance of the load-bearing channel steel, and thus improves the durability of the overall structure;

[0028] 4. The fireproof system has better durability. The durability of the system is mainly determined by the anti-corrosion and anti-rust performance of the outer additional steel plate. As long as the surface of the outer additional steel plate does not rust or melt, the fireproof performance of the system can be guaranteed. Even if rust occurs, only the outer steel needs to be rust-proofed and anti-rusted, and there is no need to repair the entire fireproof part.

[0029] 5. The appearance effect is better. The fireproofing technology of adding steel plate cavity and then grouting is adopted. The surface is only treated with anti-rust. The appearance color and appearance are well controlled, which is conducive to the use of buildings with exposed structure requirements. However, the fireproofing technology of thick fireproof coating also needs to be treated with anti-corrosion and anti-rust. The fireproof coating cannot be evenly applied, and the appearance can only be uneven, which is not beautiful and is not conducive to the use of buildings with exposed structures;

[0030] 6. Post-maintenance is simple and the maintenance cost is low. The maintenance of the traditional steel structure surface fire protection method is to repair both the anti-corrosion and anti-rust layer and the fire protection layer, while the additional steel plate cavity post-grouting fire protection technology only maintains the anti-corrosion and anti-rust layer on the outside of the additional steel plate. Compared with the traditional fire protection method, the outside of the concrete channel steel also needs to be treated and maintained for anti-corrosion and anti-rust, and this part of the maintenance cost is offset year-on-year. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of grouting after adding a steel plate cavity to the steel clad beam of the present invention;

[0032] Figure 2 It is a schematic diagram of the construction method of the present invention.

[0033] In the figure: 1. Structural steel plate for steel beam, 2. Additional steel plate, 3. Stainless steel bolts, 4. Rubber pads, 5. Reserved steel pipes, 6. Cast-in-place concrete in steel beam, 7. Cement mortar layer. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Embodiment 1

[0036] See also Figure 1 A fireproof structure of a steel-encased concrete beam with an additional steel plate cavity after grouting, comprising a structural beam-encased steel plate 1 and an additional steel plate 2; the additional steel plate 2 is arranged on the outside of the structural beam-encased steel plate 1, the structural beam-encased steel plate 1 and the additional steel plate 2 are connected by stainless steel bolts 3, the structural beam-encased steel plate 1 is poured with cast-in-place concrete 6 in the steel-encased beam, and the gap between the structural beam-encased steel plate 1 and the additional steel plate 2 is filled with a cement mortar layer 7 with the same strength grade of the structural beam concrete.

[0037] In the embodiment of the present invention, the additional steel plate 2 is wrapped in a U-shape on the outside of the structural beam steel plate 1, and the thickness of the additional steel plate 2 is 1 mm, and the outer wall of the additional steel plate 2 is coated with anti-rust paint.

[0038] In an embodiment of the present invention, the additional steel plate 2 is provided with a rubber pad 4 at the joints of the beam end and the beam top folding edge of the structural beam wrapping steel plate 1, and is sealed with a flexible fire-retardant putty to form a closed cavity between the structural beam wrapping steel plate 1 and the additional steel plate 2.

[0039] In the embodiment of the present invention, a reserved steel pipe 5 with an inner diameter of 15 mm is reserved on the top of the closed cavity along the beam side formed between the structural beam steel plate 1 and the additional steel plate 2, and the spacing between the reserved steel pipes 5 is ≤3m, and the protruding length from the floor is ≥50mm. The reserved steel pipe 5 facilitates the subsequent grouting.

[0040] In an embodiment of the present invention, both sides and the bottom of the structural beam-wrapping steel plate 1 and the additional steel plate 2 are flexibly connected by a plurality of stainless steel bolts 3 to form a whole, so that the additional steel plate 2 can be hoisted together with the structural beam-wrapping steel plate 1, and it can be ensured that the micro-deformation of the structural beam-wrapping steel plate 1 during the construction and loading process will not cause deformation of the cavity formed by the outer additional steel plate 2.

[0041] Furthermore, in the embodiment of the present invention, the cement mortar layer 7 is a cement mortar protective layer with the same structural strength grade as the cast-in-place concrete, so that it has the same fire resistance as the reinforced concrete structure.

[0042] Embodiment 2

[0043] See also Figure 2 , a construction method of a steel-clad concrete beam with an additional steel plate cavity and post-grouting fireproof structure, the construction method comprising the following steps:

[0044] Step 1: Processing of the cavity steel plate of the steel clad beam: According to the size of the steel clad beam, the top and the beam end are retracted 2cm. Process the outer surface size of the cavity as the additional steel plate, and the folding edge of the beam top and the beam end is the same as the cavity thickness;

[0045] Step 2: Installation of cavity steel plates for steel clad beams with additional steel plates: Considering that the outer steel layer is easily damaged during transportation, on-site installation before lifting is preferred.

[0046] ① The M5 stainless steel bolts are used to connect the stress-bearing channel steel and the additional cavity steel plate, with a spacing of no more than 1m. They are evenly arranged along the outer steel of the structure, and can be staggered at the bottom of the beam. A bolt is set on the edge of the additional steel plate to ensure that the folded edge is tightly attached to the channel steel. The bolt hole position is designed in advance during steel plate processing, and the holes are punched in advance in the factory. During installation, according to the length of the outer steel of the structure, support overhead is added on site through the beam end and the beam. Then the additional steel plate is aligned and fixed with M5 bolts.

[0047] ② Measures to ensure the thickness of the cavity: Before installation, steel bar heads of equal length are processed in advance and spot welded on the surface of the channel steel with a spacing of no more than 50 cm. On the one hand, this ensures the thickness of the cavity and on the other hand, it serves to connect the post-injection mortar layer with the stressed channel steel.

[0048] ③ A 3mm thick and 2cm wide rubber pad is glued to the contact area between the additional steel plate folding edge and the corresponding stressed channel steel, and is tightened by bolts set along the folding edge to form a closed cavity to avoid leakage during the post-grouting process. Flexible fireproof putty is used to fully apply between the additional outer layer edge and the support end structure and the top plate structure;

[0049] Step 3: hoisting of the cavity of the steel clad beam with additional steel plate as a whole: after the cavity steel plate of the steel clad beam with additional steel plate is installed, it is hoisted as a whole with the outer steel of the structural beam and installed on the lattice column;

[0050] Step 4: Post-grouting of the steel plate cavity of the steel clad beam: After the structural concrete is poured and cured for more than seven days, post-grouting construction can be carried out.

[0051] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0052] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A construction method for a steel ladle concrete beam with additional steel plate cavity post-grouting fireproof structure, characterized in that: The steel-encased concrete beam additional steel plate cavity post-grouting fireproof structure comprises a structural beam-encased steel plate (1) and an additional steel plate (2); the additional steel plate (2) is arranged on the outside of the structural beam-encased steel plate (1); the structural beam-encased steel plate (1) and the additional steel plate (2) are connected via stainless steel bolts (3); the structural beam-encased steel plate (1) is filled with cast-in-place concrete (6) in the steel-encased beam; and the gap between the structural beam-encased steel plate (1) and the additional steel plate (2) is filled with a cement mortar layer (7) having the same strength grade as the structural beam concrete; The additional steel plate (2) is wrapped in a U-shape on the outside of the structural beam-wrapping steel plate (1), and the thickness of the additional steel plate (2) is 1 mm, and the outer wall of the additional steel plate (2) is coated with anti-rust paint; the additional steel plate (2) is provided with a rubber pad (4) at the joints of the beam end and the beam top folding edge of the structural beam-wrapping steel plate (1), and is sealed with a flexible fireproof putty; a reserved steel pipe (5) with an inner diameter of 15 mm is reserved along the beam side at the top of the closed cavity formed between the structural beam-wrapping steel plate (1) and the additional steel plate (2), and the reserved steel pipe (5) is spaced ≤3 m, and the length protruding from the floor is ≥50 mm; the two sides and the bottom of the structural beam-wrapping steel plate (1) and the additional steel plate (2) are flexibly connected by a plurality of stainless steel bolts (3); the cement mortar layer (7) is a cement mortar protective layer with the same structural strength grade as the cast-in-place concrete; The construction method comprises the following steps: Step 1: Processing of the cavity steel plate of the additional steel plate of the steel clad beam: According to the size of the steel clad beam, the top and the beam end are retracted 2cm, which is used as the outer surface size of the cavity of the additional steel plate for processing. The folding edge of the beam top and the beam end is the same as the cavity thickness; Step 2: Installation of cavity steel plates for steel clad beams: Considering that the outer steel layer is easily damaged during transportation, on-site installation before lifting is preferred. ① The load-bearing channel steel and the additional cavity steel plate are connected by M5 stainless steel bolts with a spacing of no more than 1m. They are evenly arranged along the outer steel of the structure and staggered at the bottom of the beam. A bolt is set on the edge of the additional steel plate to ensure that the folded edge is tightly attached to the channel steel. The bolt hole position is designed in advance during steel plate processing, and the holes are drilled in advance in the factory. During installation, according to the length of the outer steel of the structure, support overhead is added on site through the beam end and the beam, and then the additional steel plate is aligned and fixed with M5 bolts; ② Measures to ensure the thickness of the cavity: Before installation, steel bar heads of equal length are processed in advance and spot welded on the surface of the channel steel with a spacing of no more than 50 cm. This not only ensures the thickness of the cavity, but also serves as a connection between the post-injection mortar layer and the stressed channel steel; ③ A 3mm thick and 2cm wide rubber pad is glued to the contact part between the additional steel plate folding edge and the corresponding stressed channel steel, and is tightened by bolts set along the folding edge to form a closed cavity to avoid leakage during the post-grouting process. Flexible fire-proof putty is used to fully apply between the additional outer layer edge and the support end structure and the top plate structure; Step 3: hoisting of the cavity of the steel clad beam with additional steel plate as a whole: after the cavity steel plate of the steel clad beam with additional steel plate is installed, it is hoisted as a whole with the outer steel of the structural beam and installed on the lattice column; Step 4: Post-grouting of the steel plate cavity of the steel clad beam: After the structural concrete is poured and cured for more than seven days, post-grouting construction can be carried out.

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