A method for reinforcing lattice steel with full bolt connection

Abstract

The present invention discloses a method for reinforcing lattice steel with full bolt connection, comprising the following steps: S1, grinding: grinding the concrete column to be reinforced with a grinding wheel machine, and grinding the four corners of the concrete column to be smooth; S2, installing lattice steel: installing a pair of lattice steel at each of the four corners of the concrete column, the lattice steel fits the column body of the concrete column, and the lattice steel is connected to the ear plate; S3, installing the tie plate. The present invention adopts the above-mentioned method for reinforcing lattice steel with full bolt connection, and according to the outer steel reinforcement method, combines the pre-tensioning technology with the full bolt connection technology, so that the lattice steel fits the concrete column, and the two form a whole to bear force together, reducing concrete cracking, effectively improving the stiffness and bearing capacity of the component, without welding and without affecting the quality of the adhesive, improving the construction efficiency and quality, and facilitating on-site installation.

Description

Technical Field

[0001] The invention relates to the technical field of building engineering, and in particular to a method for reinforcing lattice steel with full bolt connection. Background Art

[0002] There is a large proportion of old buildings in China. As the age of buildings increases, they are affected by natural phenomena such as earthquakes, fires, and rain erosion, and their stability decreases, creating safety hazards. Therefore, it is of great engineering significance to reinforce and renovate old buildings.

[0003] When the purpose of a building structure changes, the actual bearing capacity of the structure is different from the designed bearing capacity. In order to ensure the stability of the building structure, the building with changed purpose must be reinforced and renovated. The existing building reinforcement technologies mainly include: increasing the cross-section method, external steel reinforcement method, steel plate reinforcement method, replacement concrete reinforcement method, fiber bonding method, external pre-tension reinforcement method, etc.

[0004] The cross-section enlargement method increases the cross-sectional area of ​​the original component to improve its bearing capacity and rigidity, but the construction period is long, wet work is required on site, and the usable space of the house will be compressed, causing certain inconveniences.

[0005] The external steel reinforcement method refers to wrapping steel sections on the outside of the original reinforced concrete components, and reinforcing them through welding or injecting structural adhesives. The steel sections and concrete form a whole, but the external steel reinforcement method does not greatly improve the structural stiffness and requires on-site welding, which may affect the quality of the adhesive.

[0006] The load-bonded steel plate reinforcement method refers to the use of structural adhesive to bond thin steel plates on the surface of concrete components to form a composite cross-section to improve the bearing capacity, but the increase in component stiffness is small.

[0007] The replacement concrete reinforcement method uses higher-strength concrete to replace severely defective concrete, but the new and old concretes do not work well together, chiseling the original structure may cause damage, and the wet operation cycle is long.

[0008] The fiber bonding method refers to the use of structural adhesives to bond fiber cloth or fiber sheets on the surface of reinforced concrete structural components, but it does not significantly improve the structural bearing capacity and stiffness.

[0009] The external pre-tension reinforcement method refers to a reinforcement method in which high-strength steel bars or steel strands are arranged outside the component to improve or adjust the original structure and component stress by applying external pre-tension. However, when the pre-tension is small, the reinforcement effect is not obvious. When the pre-tension is too large, the bearing capacity of the structure will decrease. The optimal pre-tension is difficult to grasp and the construction process is relatively complicated.

[0010] It can be seen that the existing reinforcement methods all have certain shortcomings. Summary of the invention

[0011] The purpose of the present invention is to provide a fully bolted lattice steel reinforcement method, which solves the problems in the prior art that the structural rigidity of the outer steel reinforcement method is not greatly improved, welding affects the quality of the adhesive, and causes damage to the components.

[0012] To achieve the above object, the present invention provides a method for reinforcing lattice steel with full bolt connection, comprising the following steps:

[0013] S1. Grinding: Grinding the concrete column to be reinforced with a grinding machine to make the four corners of the concrete column smooth;

[0014] S2. Installing lattice steel: a pair of lattice steel is installed at each of the four corners of the concrete column, the lattice steel is fitted with the concrete column body, and ear plates are connected to the lattice steel;

[0015] S3, install the gusset plate: fix the gusset plate to the ear plate by bolts, and keep the nuts of the gusset plate bolts loose and free to slide; apply pre-tension force to the upper and lower parts of the lattice steel respectively, and do not install the gusset plate at the place where the pre-tension force is applied to the lattice steel, connect the pre-tension steel member to the lattice steel through the ear plate, fix the pre-tension steel member to the ear plate with bolts, and tighten the bolts to the design value of high-strength bolts, and the bolts cannot slide during the application of pre-tension force;

[0016] S4, applying pre-tension: one end of the bolt on the pre-tension steel member is fixed by a wrench, and the torque is applied to one end of the nut by a torque wrench; the process of applying torque is divided into three stages, the first stage is applied to 30% of the pre-tension design value, the second stage is applied to 60% of the pre-tension design value, and the third stage is applied to the pre-tension design value, and the pre-tension is applied completely;

[0017] S5. Reinforcement is completed: After the pre-tension is applied, the bolts on the remaining panels are tightened to the design value of the high-strength bolts, the pre-tension steel members are removed, and the panels are installed at the removed positions. After all the bolts are tightened to the design value of the high-strength bolts, the reinforcement of the concrete column is completed.

[0018] Preferably, in step S2, the lattice steel and the ear plate are transported to the construction site after welding is completed in the factory, and during the transportation, it is ensured that the lattice steel and the ear plate have no obvious deformation; after the lattice steel is transported to the construction site, it is ensured that its appearance is intact and the surface is free of rust before reinforcement.

[0019] Preferably, in step S2, when the distance between any two lattice steels is just enough to install the tie plate, it means that the lattice steel and the concrete column fit well and subsequent reinforcement can be carried out.

[0020] Preferably, in step S4, the optimal pre-tension design value is 1 / 24 of the ultimate load of the concrete column 1, and the length of the side to which the pre-tension is applied is greater than or equal to 1 / 8 of the length of the side of the concrete column.

[0021] Preferably, in step S4, the torque is applied symmetrically from top to bottom and from small to large, and the applied torque is converted into a pre-tension force on the lattice steel; after the lattice steel on one side reaches the specified torque, the torque is applied to the lattice steel on its symmetrical surface; after the upper areas of the lattice steel on four sides reach the specified torque, the torque is applied to the lower area of ​​the lattice steel; the stage is completed after the upper and lower areas of the lattice steel each reach the specified torque on all four sides.

[0022] Therefore, the present invention adopts a full bolt connection lattice steel reinforcement method of the above structure, which has the following beneficial effects:

[0023] 1. A fully bolted lattice steel reinforcement method that is convenient for on-site processing is provided, which solves the problems in the prior art such as the influence of welding on the quality of the adhesive and the cumbersome on-site welding operation.

[0024] 2. The present invention has an ingenious structure, is easy to install and operate, has a wide range of application scenarios, and greatly improves structural rigidity.

[0025] 3. The present invention enables the lattice steel and the concrete column to form a whole and bear force together, thereby increasing the force-bearing area of ​​the concrete column; the bearing capacity of the structure is improved by forming an extrusion force on the core concrete without causing damage to the components.

[0026] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of lattice steel installation according to an embodiment of a method for reinforcing lattice steel with full bolt connection according to the present invention;

[0028] Figure 2 A schematic diagram of a cross-sectional view of lattice steel installation according to an embodiment of a method for reinforcing lattice steel with full bolt connection according to the present invention;

[0029] Figure 3 A schematic diagram of a lattice steel structure of an embodiment of a method for reinforcing lattice steel with full bolt connection according to the present invention;

[0030] Figure 4 It is a schematic diagram of pre-tension reinforcement of an embodiment of a fully bolted lattice steel reinforcement method of the present invention;

[0031] Figure 5 It is a schematic diagram of a pre-tensioned steel member in an embodiment of a method for reinforcing lattice steel with full bolt connection according to the present invention;

[0032] Figure 6 It is a schematic cross-sectional view of a pre-tensioned member in an embodiment of a fully bolted lattice steel reinforcement method of the present invention.

[0033] Reference numerals

[0034] 1. Concrete column; 2. Tie plate; 3. Ear plate; 4. Lattice steel; 5. Pre-tensioned steel member; 6. Bolt; 7. Nut. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0036] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0037] Example

[0038] A method for reinforcing lattice steel with full bolt connection, characterized in that it comprises the following steps:

[0039] S1. Grinding: Use a grinding machine to carefully grind the reinforced concrete column 1 and grind the four corners of the concrete column 1 to make them smooth. Grinding does not affect the bearing capacity of the concrete column 1, and facilitates the subsequent installation of the lattice steel 4, making it easier to fit the concrete column 1.

[0040] S2. Install lattice steel: The lattice steel 4 and the ear plate 3 are welded in the factory to ensure that the welding is firm and there is no obvious deformation during transportation. After the lattice steel 4 is delivered to the construction site, ensure that its appearance is intact before reinforcement and that there is no rust on the surface of the lattice steel 4. Before installation, place the bolts 6 on the lattice steel 4 to prevent the bolts 6 from falling off during installation. Place a pair of lattice steels 4 at each of the four corners of the reinforced concrete column 1, and carefully squeeze them to make the lattice steel 4 fit the column body. When the distance between any two pieces of lattice steel 4 is just enough to install the tie plate 2, it means that the lattice steel 4 fits the concrete column 1 and subsequent reinforcement can be carried out.

[0041] S3. Install the tie plate: fix the tie plate 2 to the ear plate 3 of the lattice steel 4 with bolts 6, and keep the nuts 7 on the tie plate 2 loose and free to slide. Tightening the nuts 7 may cause the lattice steel 4 to deform, affecting the accurate application of subsequent pre-tension. Apply pre-tension at the upper and lower parts of the lattice steel 4 respectively, do not install the tie plate 2 at the place where the pre-tension is applied, install the pre-tension steel member 5 at the corresponding position of the ear plate 3, ensure that the pre-tension steel member 5 is firmly fixed to the lattice steel 4, tighten the bolts 6 between the pre-tension steel member 5 and the ear plate 3 to the design value of the high-strength bolt, and the bolts 6 cannot slide during the application of the pre-tension.

[0042] S4. Apply pre-tension: The pre-tension is applied from top to bottom and from small to large. The pre-tension application process is divided into three stages, each stage has the same steps but different torques. One end of the bolt 6 on the pre-tension steel member 5 is fixed by a wrench, and the nut 7 is applied with torque by a torque wrench, which is converted into pre-tension on the lattice steel 4.

[0043] The torque is applied symmetrically from top to bottom and from small to large. The applied torque is converted into pre-tension on the lattice steel 4. After the lattice steel 4 on one side reaches the specified torque, the torque is applied to the lattice steel 4 on its symmetrical surface. After the upper area of ​​the four-sided lattice steel 4 reaches the specified torque, the torque is applied to the lower area of ​​the lattice steel 4. After the upper and lower areas of the lattice steel 4 reach the specified torque on all four sides, the stage is completed. The above steps are repeated in the next stage, and the target pre-tension is reached after the third application. Among them, the first application is to 30% of the prestressed design value, the second application is to 60% of the prestressed design value, and the third application is to the specified prestressed design value.

[0044] Through multiple applications in three stages, the lattice steel 4 gradually hugs the concrete column 1 to prevent deformation of the lattice steel 4 caused by excessive single torque. The optimal pre-tension design value is 1 / 24 of the ultimate load of the plain concrete column 1, and the side length of the pre-tension application should not be less than 1 / 8 of the side length of the concrete column, so that the core concrete forms an extrusion pressure, inhibits concrete cracking, and effectively improves the collaborative working performance between the concrete column 1 and the lattice steel 4.

[0045] S5, reinforcement completed: A certain period of time after the pre-tension is applied, the bolts 6 on the remaining gusset plates 2 are tightened to the design value of the high-strength bolts, the pre-tension steel member 5 is removed, and the gusset plates 2 are installed at the removed position. After all the bolts 6 are tightened to the design value of the high-strength bolts, the application of the pre-tension is completed. At this point, the entire reinforcement process is completed, and the structure forms an extrusion force on the core concrete of the column.

[0046] Therefore, the present invention adopts the above-mentioned full-bolt connection lattice steel reinforcement method, and combines the pre-tensioning technology with the full-bolt connection technology according to the external steel reinforcement method, so that the lattice steel and the concrete column are fitted together, and the two form a whole to bear the force together, reducing concrete cracking, effectively improving the component stiffness and component bearing capacity, without welding and will not affect the quality of the adhesive, thereby improving construction efficiency and construction quality, and facilitating on-site installation.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for reinforcing lattice steel with full bolt connection, characterized in that: The steps include: S1. Grinding: Grinding the concrete column to be reinforced with a grinding machine to make the four corners of the concrete column smooth; S2. Installing lattice steel: a pair of lattice steel is installed at each of the four corners of the concrete column, the lattice steel is fitted with the concrete column body, and ear plates are connected to the lattice steel; S3, install the gusset plate: fix the gusset plate to the ear plate by bolts, and the nuts of the gusset plate bolts are kept loose and can slide freely; apply pre-tension force to the upper and lower parts of the lattice steel respectively, and do not install the gusset plate at the place where the pre-tension force is applied to the lattice steel, connect the pre-tension steel member to the lattice steel through the ear plate, and the pre-tension steel member includes two angle steels connected by bolts, and the angle steels are equilateral angle steels, and reinforcing ribs are arranged between the sides of the angle steels. The pre-tension steel member is fixed to the ear plate by bolts, and the screw holes are arranged on one side of the two angle steels. The bolts are tightened to the design value of high-strength bolts, and the bolts cannot slide during the application of pre-tension force; S4, applying pre-tension: one end of the bolt on the pre-tension steel member is fixed by a wrench, and the torque is applied to one end of the nut by a torque wrench; the process of applying torque is divided into three stages, the first stage is applied to 30% of the pre-tension design value, the second stage is applied to 60% of the pre-tension design value, and the third stage is applied to the pre-tension design value, and the pre-tension is applied completely; S5. Reinforcement is completed: After the pre-tension is applied, the bolts on the remaining panels are tightened to the design value of the high-strength bolts, the pre-tension steel members are removed, and the panels are installed at the removed positions. After all the bolts are tightened to the design value of the high-strength bolts, the reinforcement of the concrete column is completed.

2. A method for reinforcing lattice steel with full bolt connection according to claim 1, characterized in that: In the step S2, the lattice steel and the ear plate are transported to the construction site after welding is completed in the factory. After the lattice steel is transported to the construction site, it is ensured that its appearance is intact and the surface is free of rust before reinforcement.

3. A method for reinforcing lattice steel with full bolt connection according to claim 2, characterized in that: In step S2, when the distance between any two lattice steels is just enough to install the tie plate, it means that the lattice steels fit the concrete column and can be subsequently reinforced.

4. The method for reinforcing lattice steel with full bolt connection according to claim 1, characterized in that: In step S4, the optimal pre-tension design value is 1 / 24 of the ultimate load of the concrete column, and the length of the side to which the pre-tension is applied is greater than or equal to 1 / 8 of the length of the side of the concrete column.

5. The method for reinforcing lattice steel with full bolt connection according to claim 1, characterized in that: In step S4, the torque is applied symmetrically from top to bottom and from small to large, and the applied torque is converted into a pre-tension force on the lattice steel; after the lattice steel on one side reaches the specified torque, the torque is applied to the lattice steel on its symmetrical surface; after the upper areas of the four-sided lattice steels reach the specified torque, the torque is applied to the lower area of ​​the lattice steel; the stage is completed after the upper and lower areas of the lattice steel each reach the specified torque on all four sides.

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