A method for cutting and reinforcing a load-bearing steel structure

Abstract

The application discloses a kind of resection load-bearing steel structure and its reinforcing construction method, using the isotropic mechanical properties of steel structure steel, first the hinge joint of the steel column to be cut and steel beam is changed to rigid connection, so that it becomes a part of steel beam, then the inside of steel frame column and the new steel beam are reinforced, so that it can independently bear the upper load in the case of cutting off steel column, finally the lower flange of the new overall steel beam is reinforced for the second time, to avoid the new overall steel beam reinforced after cutting off steel column from continuously releasing stress over time, leading to deformation and cracking of the upper structure. The present application is simple, safe, short cycle, saves labor, and has good economic benefits.

Description

Technical Field

[0001] This invention relates to the technical field of existing building renovation, and in particular to a method for removing load-bearing steel structures and reinforcing them. Background Technology

[0002] my country's urbanization is nearing its end, and office and residential buildings are basically saturated. In the coming decades, a large number of old buildings that still have usable value will be reused after reinforcement and renovation. When reinforcement or functional changes are involved, the lower steel columns are often removed while the upper structure is still under load. However, according to incomplete statistics from relevant departments, more than two-thirds of engineering structure collapses in my country occur during the construction phase, especially demolition projects, which are even more dangerous. Therefore, it is imperative to adopt safe and economical removal techniques.

[0003] Currently, there are two main methods for dismantling load-bearing steel columns. Method 1: Using full-scale scaffolding for backfilling, with backfilling occurring on multiple lower floors. This method involves the entire structural load of the upper floors being borne by the scaffolding after the steel column is dismantled but before the steel beams are reinforced. This poses significant safety risks, a long dismantling and assembly cycle, high costs, and is prone to structural deformation and cracking. Furthermore, the scaffolding's location severely impacts subsequent decoration and installation work due to its occupation of the work surface. Method 2: Before dismantling the steel column, using custom-made temporary steel supports on both sides of the column to temporarily replace it and bear the upper load. This method involves a long period of feasibility studies, component fabrication, and dismantling / assembly; it is also costly. The backfilling force of the temporary supports is difficult to control; excessive force may cause deformation of the steel beams above or below the supports, and cracking of the concrete structure; insufficient force may cause deformation and subsidence of the upper steel beams after the column is removed, and cracking of the concrete structure. Originally, the upper floor load was transferred to the lower floors through the steel column, but because of the backfilling of the steel supports, the load is transferred to the lower floor beams, which may not be able to withstand the transmitted load. The partial occupation of the work surface also affects subsequent decoration and installation work. Summary of the Invention

[0004] This invention provides a method for cutting off load-bearing steel structures and reinforcing them, in order to solve the above-mentioned problems.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This invention discloses a method for removing and reinforcing load-bearing steel structures, comprising the following steps:

[0007] Step 1: Change the hinged joint between the steel column and the steel beam to be cut to a rigid joint, so that the original steel beams on both sides of the steel column to be cut are connected to form a new integral steel beam.

[0008] Step 2: Reinforce the steel beam by increasing its cross-section;

[0009] Step 3: Cut the steel column to be removed.

[0010] The present invention discloses a method for cutting off load-bearing steel structures and reinforcing them. Further, in step 1, the edge of the connecting plate where the steel column to be cut off is bolted to the steel beam is surrounded by double-sided fillet welds to realize the transformation from hinged connection to rigid connection.

[0011] The present invention discloses a method for cutting off and reinforcing a load-bearing steel structure. Further, in step 2, a reinforcing structure is welded to the lower flange of the steel beam.

[0012] This invention discloses a method for removing load-bearing steel structures and reinforcing them. Further, the reinforcing structure includes a reinforcing beam web and reinforcing beam flanges. The reinforcing beam web is positioned on the lower flange of the steel beam, corresponding to the position of the steel beam web. Its upper part is connected to the lower flange of the steel beam, and its two ends are connected to the steel frame columns on both sides of the steel column to be removed. The top surface of the reinforcing beam flange is connected to the reinforcing beam web, and its two ends are connected to the steel frame columns.

[0013] The present invention discloses a method for cutting off and reinforcing a load-bearing steel structure. Furthermore, the steel frame column is provided with an internal stiffening plate, and the internal stiffening plate and the flange of the reinforcing beam are located at the same elevation.

[0014] The present invention discloses a method for cutting off load-bearing steel structures and reinforcing them, wherein a continuous reinforcing flange is welded to the lower part of the reinforcing beam flange.

[0015] The present invention discloses a method for cutting off load-bearing steel structures and reinforcing them. Further, steel beam stiffening plates are welded to the steel beams on both sides of the steel column to be cut off and to the cross-sectional reinforcement structure formed therefrom. The steel beam stiffening plates are spaced apart along the length of the steel beams.

[0016] This invention discloses a method for cutting off load-bearing steel structures and reinforcing them, further comprising using a static cutting process to cut the steel columns to be cut off.

[0017] The present invention discloses a method for cutting off load-bearing steel structures and reinforcing them. Furthermore, before cutting the steel column to be cut off, the newly added welds are inspected.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This application utilizes the isotropic mechanical properties of steel in steel structures. First, the hinged joint between the steel column and the steel beam to be removed is changed to a rigid joint, making it part of the steel beam. Then, the interior of the steel frame column and the new steel beam are reinforced so that they can independently bear the upper load when the steel column is removed. Finally, the lower flange of the new integral steel beam is reinforced again to avoid deformation and cracking of the upper structure due to the continuous release of stress in the new integral steel beam after the steel column is removed.

[0020] 2. Construction is convenient and safe, with the upper load transferred to the predetermined beams and columns through structural components at each step;

[0021] 3. Simple to operate, highly efficient, short cycle, does not occupy the work surface for decoration and installation, and does not affect the decoration schedule;

[0022] 4. It will not cause structural deformation, cracking, or other quality or safety hazards;

[0023] 5. The economic benefits are considerable, saving a lot of labor, materials, machinery and transportation costs for disassembly and assembly.

[0024] The invention will now be further described with reference to the accompanying drawings. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the current structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the web of the welded reinforced beam of the present invention;

[0027] Figure 3 This is a schematic diagram of the installation of the reinforcing beam flange and internal stiffening plate of the present invention;

[0028] Figure 4 This is a schematic diagram of the installation of the steel beam stiffening plate according to the present invention;

[0029] Figure 5 This is a schematic diagram illustrating the completion of the cutting of the steel column to be removed according to the present invention;

[0030] Figure 6 This is a schematic diagram of the installation of the reinforcing flange in this invention.

[0031] Figure label:

[0032] 1. Steel column to be removed; 2. Steel beam; 3. Reinforced beam web; 4. Reinforced beam flange; 5. Internal stiffening plate; 6. Steel beam stiffening plate; 7. Reinforced flange; 8. Steel frame column. Detailed Implementation

[0033] like Figures 1-6 As shown, this invention discloses a method for removing load-bearing steel structures and reinforcing them, comprising the following steps:

[0034] Step 1:

[0035] First, clean the fireproof coating at the bolted connection between the steel column 1 to be cut and the steel beam 2. Then, use double-sided fillet welds to surround the edge of the connecting plate where the steel column 1 to be cut and the steel beam 2 are bolted, so that the original core area of ​​the beam and column is changed from hinged to rigid, making the steel column 1 to be cut become part of the steel beam 2, and connecting the original steel beams 2 on both sides of the steel column 1 to be cut into a new integral steel beam.

[0036] Step 2:

[0037] A reinforcing structure is welded to the lower flange of steel beam 2 to enhance its load-bearing capacity. The reinforcing structure includes a reinforcing beam web 3 and a reinforcing beam flange 4. The reinforcing beam web 3 and the reinforcing beam flange 4 are installed at the bottom of steel beam 2 in an inverted "T" shape. The reinforcing beam web 3 is set on the lower flange of steel beam 2, and its position corresponds to the position of the web of steel beam 2. The upper part is welded to the lower flange of steel beam 2, and the two ends are welded to the steel frame columns 8 on both sides of the steel column 1 to be cut off. The top surface of the reinforcing beam flange 4 is welded to the reinforcing beam web 3, and the two ends are welded to the steel frame columns 8.

[0038] Then, internal stiffening plates 5 are installed in the steel frame columns 8 at both ends. The internal stiffening plates 5 and the flanges of the reinforcing beams 4 are at the same elevation, so that the flanges of the reinforcing beams 4 and the newly added internal stiffening plates 5 in the steel frame columns 8 are connected, effectively transmitting the horizontal force of the newly added flanges of the reinforcing beams 4.

[0039] Step 3:

[0040] Steel beam stiffening plates 6 are welded between the steel beams 2 on both sides of the steel column 1 to be cut off and the flanges of the reinforcing structure. The steel beam stiffening plates 6 are spaced apart along the length of the steel beam 2. After completion, the newly added welds are inspected to ensure they meet the design requirements.

[0041] Step 4:

[0042] The steel column 1 to be removed was cut using a static cutting process. Before cutting, a truck crane was used to secure the steel column 1 to be removed. After the cutting was completed, the truck crane lifted the steel column 1 to be removed to the ground floor.

[0043] Step 5:

[0044] A continuous reinforcing flange 7 is welded to the lower part of the reinforcing beam flange 4. The weld is inspected again, ground to remove rust, and then coated with zinc-rich anti-rust primer, followed by epoxy micaceous iron oxide intermediate paint. After it dries, fireproof coating is applied. By welding a continuous reinforcing flange 7 to the lower part of the reinforcing beam flange 4, the stress on the steel beam 2 is continuously released over time after the steel column is cut off, which may cause deformation or cracks.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for cutting off and reinforcing a load-bearing steel structure, characterized in that, Includes the following steps: Step 1: Change the hinged joint between the steel column and the steel beam to be cut to a rigid joint. Specifically, the edge of the connecting plate that connects the steel column and the steel beam to be cut is welded with double-sided fillet welds to realize the transformation from hinged to rigid joint; so that the original steel beams on both sides of the steel column to be cut are connected to form a new integral steel beam. Step 2: Reinforce the steel beam by increasing its cross-section; weld a reinforcing structure to the lower flange of the steel beam. The reinforcing structure includes a reinforcing beam web and a reinforcing beam flange. The reinforcing beam web is placed on the lower flange of the steel beam, and its position corresponds to that of the steel beam web. Its upper part is connected to the lower flange of the steel beam, and its two ends are connected to the steel frame columns on both sides of the steel column to be removed; the top surface of the reinforcing beam flange is connected to the reinforcing beam web, and its two ends are connected to the steel frame columns. Step 3: Cut the steel column to be removed.

2. The method for cutting off and reinforcing a load-bearing steel structure according to claim 1, characterized in that: The steel frame column is equipped with an internal stiffening plate, and the internal stiffening plate and the flange of the reinforcing beam are at the same elevation.

3. The method for cutting off and reinforcing a load-bearing steel structure according to claim 1, characterized in that: A full-length reinforcing flange is welded to the lower part of the reinforcing beam flange.

4. The method for cutting off and reinforcing a load-bearing steel structure according to claim 1, characterized in that: Steel beam stiffening plates are welded to the steel beams on both sides of the steel column to be cut off and to the cross-sectional reinforcement structure formed therefrom. The steel beam stiffening plates are spaced apart along the length of the steel beam.

5. The method for cutting off and reinforcing a load-bearing steel structure according to claim 1, characterized in that: The steel column to be removed was cut using a static cutting process.

6. A method for cutting off and reinforcing a load-bearing steel structure according to any one of claims 1-4, characterized in that: Before cutting the steel column to be removed, the newly added welds are inspected for defects.

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