A method for reinforcing weld defects at steel frame joints

Abstract

This invention discloses a method for reinforcing weld defects at steel frame joints, comprising the following steps: 1. Calculating the specifications of the reinforcing plates according to the formula; 2. Processing the reinforcing plates according to their specifications; 3. Cleaning the steel frame; 4. Marking and positioning the H-beam and steel column to be reinforced; 5. Welding the two reinforcing plates to the H-beam, steel column, and reinforcing plates; 6. Inspecting the welds after welding, and then applying anti-corrosion and fire-retardant coatings to complete the reinforcement of the weld defects at the steel frame joints. This invention, by symmetrically arranging two reinforcing plates on both sides of the web of the H-beam and then welding them, allows the reinforcing plates to be welded to the bottom of the upper flange of the H-beam, the top of the lower flange of the H-beam, and the outer flange of the steel column. This changes the joint form and the force transmission path, enabling the beam-end bending moment to be effectively transmitted to the column end, ensuring structural safety and achieving steel frame reinforcement without the need for partial removal of the upper floor slab.

Description

Technical Field

[0001] This invention belongs to the field of steel frame welding defect reinforcement technology, specifically relating to a reinforcement method for welding defects at steel frame nodes. Background Technology

[0002] During the inspection of steel frame structures, structural inspectors have repeatedly found that while the high-strength bolt connections at the beam webs of the steel frame structure nodes are normal, serious quality defects such as unwelded or embedded reinforcing bars exist at the connections of the upper and lower flanges of the H-beams and the steel columns, affecting the overall structural safety.

[0003] During construction, welding defects in steel frame joints are typically discovered during weld inspection, and the usual solution is to remove and re-weld them. However, due to inadequate standardization and completeness in construction, supervision, and acceptance processes during the development of steel structures, an increasing number of existing steel structure buildings are found to have such problems during subsequent inspections. Currently, the solution involves partially chiseling away the floor slab above the beam flange, then cleaning and re-welding the unwelded areas. This method is difficult and costly, and in some buildings, the presence of underfloor heating, floor tiles, or other finishing layers makes the time, cost, and impact of such repairs unacceptable to the client. Furthermore, existing reinforcement methods are limited by the space constraints of the floor slab above the beam flange, making it impossible to reinforce without removing the slab. Therefore, research on reinforcement methods for steel structure joints with welding defects (unwelded, with embedded reinforcing bars) under the spatial constraint of not damaging the upper floor slab and ancillary facilities has significant theoretical and practical value.

[0004] Therefore, a reinforcement method for welding defects at steel frame joints is needed. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a reinforcement method for welding defects at steel frame joints, addressing the shortcomings of the prior art. This method involves symmetrically arranging two reinforcing plates on both sides of the web of an H-beam and then welding them together. The reinforcing plates are welded to the bottom of the upper flange of the H-beam, the top of the lower flange of the H-beam, and the outer flange of the steel column. By welding reinforcing plates to the joints of existing steel frame structures with welding defects, the joint form is changed, and the force transmission path is altered. This allows the bending moment at the beam end to be effectively transmitted to the column end, ensuring structural safety and achieving reinforcement of the steel frame without requiring partial removal of the upper floor slab.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for reinforcing welding defects in steel frame joints, characterized in that the method includes the following steps:

[0007] t jb =(H b -2bf -2s)t w / 2(H b -2b f (1);

[0008] h JG =H b -2b f (2);

[0009] l JG =M / 2(H b -2b f )h e f f w +2h f (3);

[0010] Among them, t jb To reinforce the thickness of the plate, H b b is the height of the H-beam at the steel frame joint. f t is the flange width of the H-beam at the steel frame joint, s is the height of the weld hole at the web of the H-beam in the steel frame, and t is the height of the weld hole. w h is the thickness of the web of the H-beam in the steel frame. JG To reinforce the height of the plate, l JG M is the width of the reinforcing plate, M is the bending moment at the end of the H-beam, and h is the bending moment at the end of the H-beam. e f is the effective thickness of the fillet weld. f w h is the design strength value for the fillet weld. f This refers to the weld leg size for a fillet weld.

[0011] Step 2: Process the reinforcement plate according to the specifications obtained in Step 1 to obtain the reinforcement plate;

[0012] Step 3: Remove the bottom of the upper flange of the H-beam, the top of the lower flange of the H-beam, and the outer flange of the steel column to obtain the H-beam and steel column to be reinforced.

[0013] Step 4: Mark the H-beams and columns to be reinforced obtained in Step 3; the marking points are located at the midpoint of the extended flange of the H-beam, and two reinforcing plates are symmetrically arranged on both sides of the web of the H-beam to be reinforced.

[0014] Step 5: Install the two reinforcing plates obtained in Step 2 according to the positions marked in Step 4, and then weld the H-beams, steel columns and reinforcing plates.

[0015] Step Six: Inspect the welds between the reinforced plate and the H-beam and steel column after welding in Step Five. Then, apply anti-corrosion coating and fireproof coating to the welded and cleaned areas in sequence to complete the reinforcement of the welding defects at the steel frame nodes.

[0016] This invention proposes a formula for calculating the dimensions of the reinforcing plate based on the parameters of the H-beam at the required steel frame joint, wherein the thickness t of the reinforcing plate is... jb The determination is based on the principle that the sum of the cross-sectional areas of the connecting parts of the reinforcing plates should not be less than the cross-sectional area of ​​the connecting parts of the original structural steel beams, i.e. (H b -2 bf -2s)t w =2t jb (H b -2 bf ), where, based on the actual value, the thickness of the reinforcing plate is taken as t. jb =(H b -2b f -2s)t w / 2(H b -2b f Furthermore, based on structural requirements, the minimum thickness of the reinforcing plate must not be less than 6mm, and the height h of the reinforcing plate must be [not specified]. JG The width of the reinforcing plate is determined based on the need for the reinforcing plate to connect to the bottom of the upper flange and the top of the lower flange of the H-beam. JG Based on the design of the steel frame joint, it can be seen that the shear force at the end of the H-beam is entirely transmitted by the web of the H-beam, while the bending moment is entirely transmitted by the flanges of the H-beam. Due to this defect, the shear force at the end of the steel beam at the joint is transmitted to the steel column via the web, while the bending moment at the end of the steel beam cannot be transmitted to the steel column because the upper flange was not welded during construction. After reinforcement, the force transmission mode of this joint can be simplified to continue to bear the shear force by the original structural steel beam web, while the bending moment transmitted by the flange is transferred to two steel plates at symmetrical positions after reinforcement through a welded connection. Therefore, according to the moment balance, we get: M = 2N(H b -2 bf —①, According to the calculation formula for fillet welds, N = h e ∑l w f f w —②, Based on equations ① and ②, the calculated length ∑l of the reinforced fillet weld is obtained. w =M / 2(H b -2 bf )h e f f w According to the design specification formula: actual reinforcement plate length l JG =∑l w +2hf That is, l JG =M / 2(H b -2b f )h e f f w +2h f Where M is the bending moment at the end of the H-section steel beam, which can be calculated from the actual working conditions, h e f is the effective thickness of the fillet weld. f w h is the design strength value for the fillet weld. f This refers to the fillet weld size, where the fillet weld represents the weld between the reinforcing plate and the H-beam. The fillet weld size is determined based on the thickness of the reinforcing plate. When the thickness of the reinforcing plate is t... jb When ≤6mm, When the thickness t of the reinforcing plate jb When h > 6mm f =t jb -(1~2)mm, the above parameters can be calculated and obtained by referring to the steel structure design specifications. This invention calculates the specifications of the reinforcement plate to ensure that the reinforcement plate achieves the best reinforcement effect under the condition of the least amount of material required. This invention removes impurities from the surface of the bottom of the upper flange of the H-beam, the top of the lower flange of the H-beam, and the outer flange of the steel column to ensure the effect of subsequent welding, thereby improving the reinforcement effect. The installation position of the fixing plate is determined by drawing lines to determine that two reinforcement plates are symmetrically arranged on both sides of the web of the H-beam, and the fixing plate is located at the midpoint of the extended part of the flange of the H-beam. Then welding is carried out so that the reinforcement plate is welded to the bottom of the upper flange of the H-beam, the top of the lower flange of the H-beam, and the outer flange of the steel column. The reinforcement plate is welded to the joint of the existing steel frame structure with welding defects, changing the joint form and changing the force transmission path, so that the bending moment at the beam end can be effectively transmitted to the column end, ensuring structural safety and realizing the reinforcement of the steel frame.

[0017] The above-mentioned method for reinforcing weld defects at steel frame joints is characterized in that the steel grade of the reinforcing plate in step two is not lower than that of the H-beam and steel column. Since the reinforcing material is welded to the original structure, equal-strength welding is required. Therefore, the base material and the reinforcing plate must maintain a strength grade not lower than that of the base material, and in the reinforcement design, the reinforcing material is generally selected with a strength grade not lower than that of the base material.

[0018] The above-mentioned method for reinforcing weld defects at steel frame joints is characterized in that, in step two, the connection between the reinforcing plate and the steel column is beveled, and the connection between the reinforcing plate and the H-beam is ground. This invention, by beveling and grinding the connections between the reinforcing plate and the steel column and the H-beam respectively, ensures the effectiveness of subsequent welding connections, thereby improving the connection stability between the reinforcing plate and the steel column and the H-beam.

[0019] The above-mentioned reinforcement method for welding defects in steel frame joints is characterized in that, in step three, the cleaning involves using a hammer and angle grinder to polish the fireproof and anti-corrosion coating at the connection between the H-beam and steel column and the reinforcement plate until a metallic luster is exposed. The polishing length at the bottom of the upper flange and the top of the lower flange of the H-beam is the width of the reinforcement plate plus 80mm to 120mm. The polishing height of the outer flange of the steel column is the same as the height of the H-beam. This invention removes the original fireproof and anti-corrosion coating through polishing, and all polished areas are welding areas. This ensures the effectiveness of subsequent welding connections by welding the reinforcement plate to the original structure during reinforcement, thereby improving the connection stability between the reinforcement plate and the steel column and H-beam.

[0020] The above-described method for reinforcing weld defects at steel frame joints is characterized in that the welding electrode used in step five has the same grade as the lower grade of the steel material grade for the H-beam and column. The steel structure welding specifications of this invention stipulate that the welding electrode grade is related to the steel material grade of the H-beam and column.

[0021] The above-mentioned method for reinforcing weld defects at steel frame joints is characterized in that, in step five, CO2 gas shielded welding is used for welding. The welding involves first spot welding the three sides connecting the reinforcing plate to the H-beam and the steel column for positioning, followed by continued welding to ensure a firm bond. The weld connecting the reinforcing plate to the flange of the steel column is a full-penetration single-sided V-groove weld, and the weld connecting the reinforcing plate to the bottom of the upper flange and the top of the lower flange of the H-beam is a fillet weld. This invention, by controlling the welds between the reinforcing plate and the steel column and H-beam, ensures the effectiveness of the welded connection, thereby improving the connection stability between the reinforcing plate and the steel column and H-beam.

[0022] The above-mentioned method for reinforcing steel frame joint welding defects is characterized in that the weld inspection process in step six is ​​as follows: 24 hours after welding is completed, the appearance quality of the full penetration single-sided V-groove weld must meet the requirements of a Class I weld, the ultrasonic testing must meet the requirements of a Class II weld, and the appearance quality of the fillet weld must meet the requirements of a Class II weld. This invention, through weld inspection, inspects the reinforced steel frame to ensure that the reinforced steel frame meets the usage requirements.

[0023] The above-mentioned method for reinforcing weld defects at steel frame joints is characterized in that, in step six, the thickness of the anti-corrosion coating obtained by applying the anti-corrosion coating is not less than 200 μm, and the thickness of the fireproof coating obtained by applying the fireproof coating is less than 2.5 mm when applied thinly or ultra-thinly, and less than 30 mm when applied thickly. In this invention, the thickness of the anti-corrosion coating is not less than the original design coating thickness. Fireproof coating can only be applied after the anti-corrosion coating thickness has passed inspection, and the thickness of the fireproof coating must not be less than the original design thickness. If the original design does not specify the thickness of the anti-corrosion and fireproof coatings, the thickness requirements shall be followed during construction. Furthermore, in actual engineering projects, the fireproof coating may have different requirements for thin, ultra-thin, or thick applications, and different thicknesses shall be selected according to these different requirements.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. This invention involves symmetrically arranging two reinforcing plates on both sides of the web of an H-shaped steel beam and then welding them together. The reinforcing plates are then welded to the bottom of the upper flange of the H-shaped steel beam, the top of the lower flange of the H-shaped steel beam, and the outer flange of the steel column. This welding of reinforcing plates to the joints of existing steel frame structures with welding defects changes the joint form and the force transmission path, allowing the beam-end bending moment to be effectively transmitted to the column end, ensuring structural safety and achieving steel frame reinforcement. This invention proposes a method for reinforcing the upper flange welding defects at the joints of H-shaped steel columns and steel beams without damaging the upper floor slab. The method is simple to construct, low in cost, short in construction period, and has good reinforcement effect. The most significant advantage is that it eliminates the need for partial removal of the upper floor slab.

[0026] 2. Based on the parameters of the H-beam to be reinforced, this invention calculates the size of the reinforcing plate, ensuring that the reinforcing plate achieves the best reinforcement effect with the least amount of material required.

[0027] 3. This invention welds reinforcing plates to the joints of existing steel frame structures with welding defects, changes the joint form, and alters the force transmission path, so that the bending moment at the beam end can be effectively transmitted to the column end, ensuring structural safety.

[0028] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the H-shaped steel beam and steel column to be reinforced according to the present invention.

[0030] Figure 2 This is a schematic diagram showing the connection relationship between the welded reinforcing plate of this invention and the H-shaped steel beam and steel column.

[0031] Figure 3 yes Figure 2 AA cross-section view.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1—Reinforcing plate; 2—H-beam; 2-1—Upper flange;

[0034] 2-2—Lower flange; 2-3—Web plate; 3—Steel column. Detailed Implementation

[0035] Figure 1 This is a structural schematic diagram of the H-shaped steel beam and steel column to be reinforced according to the present invention. Figure 1 It can be seen that the upper flange 2-1 and lower flange 2-2 of the H-shaped steel beam 2 to be reinforced in this invention have welding defects with the steel column 3.

[0036] Figure 2 This is a schematic diagram showing the connection relationship between the welded reinforcing plate of this invention and the H-beam and steel column. Figure 3 yes Figure 2 AA section view, from Figure 2 and Figure 3 It can be seen that two reinforcing plates 1 are symmetrically arranged on both sides of the web 2-3 of the H-beam 2. The upper end of the reinforcing plate 1 is welded to the bottom of the upper flange 2-1 of the H-beam 2, and the lower end of the reinforcing plate 1 is welded to the top of the lower flange 2-2 of the H-beam 2. The side of the reinforcing plate 1 closest to the steel column 3 is welded to the steel column 3.

[0037] Example 1

[0038] This embodiment includes the following steps:

[0039] Step 1: Calculate the specifications of the reinforcement plate using the following formula:

[0040] t jb =(H b -2b f -2s)t w / 2(H b -2b f (1);

[0041] h JG =H b -2b f (2);

[0042] l JG =M / 2(H b -2b f )h e f f w +2h f (3);

[0043] Among them, t jb To reinforce the thickness of the plate, H b b is the height of the H-beam at the steel frame joint.f t is the flange width of the H-beam at the steel frame joint, s is the height of the weld hole at the web of the H-beam in the steel frame, and t is the height of the weld hole. w h is the thickness of the web of the H-beam in the steel frame. JG To reinforce the height of the plate, l JG M is the width of the reinforcing plate, M is the bending moment at the end of the H-beam, and h is the bending moment at the end of the H-beam. e f is the effective thickness of the fillet weld. f w h is the design strength value for the fillet weld. f This refers to the weld leg size for a fillet weld.

[0044] Step 2: Process the reinforcing plate according to the specifications obtained in Step 1 to obtain the reinforcing plate; the steel grade of the reinforcing plate shall not be lower than that of the H-beam and steel column; the connection between the reinforcing plate and the steel column shall be beveled, and the connection between the reinforcing plate and the H-beam shall be ground.

[0045] Step 3: Clean the bottom of the upper flange of the H-beam, the top of the lower flange of the H-beam, and the outer flange of the steel column to obtain the H-beam and steel column to be reinforced. The cleaning involves using a hammer and an angle grinder to polish the fireproof and anti-corrosion coating at the connection between the H-beam and steel column and the reinforcement plate until the metal luster is exposed. The polishing length of the bottom of the upper flange and the top of the lower flange of the H-beam is the width of the reinforcement plate plus 100mm. The polishing height of the outer flange of the steel column is the same as the height of the H-beam.

[0046] Step 4: Mark the H-beams and columns to be reinforced obtained in Step 3; the marking points are located at the midpoint of the extended flange of the H-beam, and two reinforcing plates are symmetrically arranged on both sides of the web of the H-beam to be reinforced.

[0047] Step 5: Install the two reinforcing plates obtained in Step 2 according to the positions marked in Step 4, and then weld the H-beam, steel column, and reinforcing plates. The welding rods used for welding are of the same grade as the lower grade of the steel material of the H-beam and steel column. The welding is performed using CO2 gas shielded welding. The three sides connecting the reinforcing plate to the H-beam and steel column are first tack welded for positioning, and then welded firmly. The weld connecting the reinforcing plate to the flange of the steel column is a full penetration single-sided V-groove weld, and the weld connecting the reinforcing plate to the bottom of the upper flange of the H-beam and the top of the lower flange of the H-beam is a fillet weld.

[0048] Step Six: Inspect the welds between the reinforced plate and the H-beam and steel column after welding in Step Five. Then, apply anti-corrosion coating and fire-retardant coating to the welded and cleaned areas in sequence to complete the reinforcement of the welding defects at the steel frame nodes. The thickness of the anti-corrosion coating obtained by applying the anti-corrosion coating shall not be less than 200μm, and the fire-retardant coating obtained by applying the fire-retardant coating shall be a thin coating with a thickness of less than 2.5mm.

[0049] After testing, it was found that 24 hours after the welding was completed, the appearance quality of the full penetration single-sided V-groove weld met the requirements of Class I weld, the ultrasonic testing met the requirements of Class II weld, the appearance quality of the fillet weld met the requirements of Class II weld, and the reinforced H-beam and steel column were firmly connected.

[0050] Example 2

[0051] This embodiment includes the following steps:

[0052] Step 1: Calculate the specifications of the reinforcement plate using the following formula:

[0053] t jb =(H b -2b f -2s)t w / 2(H b -2b f (1);

[0054] h JG =H b -2b f (2);

[0055] l JG =M / 2(H b -2b f )h e f f w +2h f (3);

[0056] Among them, t jb To reinforce the thickness of the plate, H b b is the height of the H-beam at the steel frame joint. f t is the flange width of the H-beam at the steel frame joint, s is the height of the weld hole at the web of the H-beam in the steel frame, and t is the height of the weld hole. w h is the thickness of the web of the H-beam in the steel frame. JG To reinforce the height of the plate, l JG M is the width of the reinforcing plate, M is the bending moment at the end of the H-beam, and h is the bending moment at the end of the H-beam. e f is the effective thickness of the fillet weld. f w h is the design strength value for the fillet weld.f This refers to the weld leg size for a fillet weld.

[0057] Step 2: Process the reinforcing plate according to the specifications obtained in Step 1 to obtain the reinforcing plate; the steel grade of the reinforcing plate shall not be lower than that of the H-beam and steel column; the connection between the reinforcing plate and the steel column shall be beveled, and the connection between the reinforcing plate and the H-beam shall be ground.

[0058] Step 3: Clean the bottom of the upper flange of the H-beam, the top of the lower flange of the H-beam, and the outer flange of the steel column to obtain the H-beam and steel column to be reinforced. The cleaning involves using a hammer and an angle grinder to polish the fireproof and anti-corrosion coating at the connection between the H-beam and the steel column and the reinforcement plate until the metal luster is exposed. The grinding length of the bottom of the upper flange and the top of the lower flange of the H-beam is the width of the reinforcement plate plus 80mm. The grinding height of the outer flange of the steel column is the same as the height of the H-beam.

[0059] Step 4: Mark the H-beams and columns to be reinforced obtained in Step 3; the marking points are located at the midpoint of the extended flange of the H-beam, and two reinforcing plates are symmetrically arranged on both sides of the web of the H-beam to be reinforced.

[0060] Step 5: Install the two reinforcing plates obtained in Step 2 according to the positions marked in Step 4, and then weld the H-beam, steel column, and reinforcing plates. The welding rods used for welding are of the same grade as the lower grade of the steel material of the H-beam and steel column. The welding is performed using CO2 gas shielded welding. The three sides connecting the reinforcing plate to the H-beam and steel column are first tack welded for positioning, and then welded firmly. The weld connecting the reinforcing plate to the flange of the steel column is a full penetration single-sided V-groove weld, and the weld connecting the reinforcing plate to the bottom of the upper flange of the H-beam and the top of the lower flange of the H-beam is a fillet weld.

[0061] Step Six: Inspect the welds between the reinforced plate and the H-beam and steel column after welding in Step Five. Then, apply anti-corrosion coating and fire-retardant coating to the welded and cleaned areas in sequence to complete the reinforcement of the welding defects at the steel frame nodes. The thickness of the anti-corrosion coating obtained by applying the anti-corrosion coating is not less than 200μm, and the fire-retardant coating obtained by applying the fire-retardant coating is an ultra-thin coating with a thickness of less than 2.5mm.

[0062] After testing, it was found that 24 hours after the welding was completed, the appearance quality of the full penetration single-sided V-groove weld met the requirements of Class I weld, the ultrasonic testing met the requirements of Class II weld, the appearance quality of the fillet weld met the requirements of Class II weld, and the reinforced H-beam and steel column were firmly connected.

[0063] Example 3

[0064] This embodiment includes the following steps:

[0065] Step 1: Calculate the specifications of the reinforcement plate using the following formula:

[0066] t jb =(H b -2b f -2s)t w / 2(H b -2b f (1);

[0067] h JG =H b -2b f (2);

[0068] l JG =M / 2(H b -2b f )h e f f w +2h f (3);

[0069] Among them, t jb To reinforce the thickness of the plate, H b b is the height of the H-beam at the steel frame joint. f t is the flange width of the H-beam at the steel frame joint, s is the height of the weld hole at the web of the H-beam in the steel frame, and t is the height of the weld hole. w h is the thickness of the web of the H-beam in the steel frame. JG To reinforce the height of the plate, l JG M is the width of the reinforcing plate, M is the bending moment at the end of the H-beam, and h is the bending moment at the end of the H-beam. e f is the effective thickness of the fillet weld. f w h is the design strength value for the fillet weld. f This refers to the weld leg size for a fillet weld.

[0070] Step 2: Process the reinforcing plate according to the specifications obtained in Step 1 to obtain the reinforcing plate; the steel grade of the reinforcing plate shall not be lower than that of the H-beam and steel column; the connection between the reinforcing plate and the steel column shall be beveled, and the connection between the reinforcing plate and the H-beam shall be ground.

[0071] Step 3: Clean the bottom of the upper flange of the H-beam, the top of the lower flange of the H-beam, and the outer flange of the steel column to obtain the H-beam and steel column to be reinforced. The cleaning involves using a hammer and an angle grinder to polish the fireproof and anti-corrosion coating at the connection between the H-beam and steel column and the reinforcement plate until the metal luster is exposed. The polishing length of the bottom of the upper flange and the top of the lower flange of the H-beam is the width of the reinforcement plate plus 120mm. The polishing height of the outer flange of the steel column is the same as the height of the H-beam.

[0072] Step 4: Mark the H-beams and columns to be reinforced obtained in Step 3; the marking points are located at the midpoint of the extended flange of the H-beam, and two reinforcing plates are symmetrically arranged on both sides of the web of the H-beam to be reinforced.

[0073] Step 5: Install the two reinforcing plates obtained in Step 2 according to the positions marked in Step 4, and then weld the H-beam, steel column, and reinforcing plates. The welding rods used for welding are of the same grade as the lower grade of the steel material of the H-beam and steel column. The welding is performed using CO2 gas shielded welding. The three sides connecting the reinforcing plate to the H-beam and steel column are first tack welded for positioning, and then welded firmly. The weld connecting the reinforcing plate to the flange of the steel column is a full penetration single-sided V-groove weld, and the weld connecting the reinforcing plate to the bottom of the upper flange of the H-beam and the top of the lower flange of the H-beam is a fillet weld.

[0074] Step Six: Inspect the welds between the reinforced plate and the H-beam and steel column after welding in Step Five. Then, apply anti-corrosion coating and fire-retardant coating to the welded and cleaned areas in sequence to complete the reinforcement of the welding defects at the steel frame joints. The thickness of the anti-corrosion coating obtained by applying the anti-corrosion coating shall not be less than 200μm, and the thickness of the fire-retardant coating obtained by applying the fire-retardant coating shall be less than 30mm.

[0075] After testing, it was found that 24 hours after the welding was completed, the appearance quality of the full penetration single-sided V-groove weld met the requirements of Class I weld, the ultrasonic testing met the requirements of Class II weld, the appearance quality of the fillet weld met the requirements of Class II weld, and the reinforced H-beam and steel column were firmly connected.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for reinforcing weld defects at steel frame joints, characterized in that, The method includes the following steps: Step 1: Calculate the specifications of the reinforcement plate using the following formula: t jb =(H b -2b f -2s)t w / 2(H b -2b f )(1); h JG =H b -2b f (2); l JG =M / 2(H b -2b f )h e f f w +2h f (3); Among them, t jb To reinforce the thickness of the plate, H b b is the height of the H-beam at the steel frame joint. f t is the flange width of the H-beam at the steel frame joint, s is the height of the weld hole at the web of the H-beam in the steel frame, and t is the height of the weld hole. w h is the thickness of the web of the H-beam in the steel frame. JG To reinforce the height of the plate, l JG M is the width of the reinforcing plate, M is the bending moment at the end of the H-beam, and h is the bending moment at the end of the H-beam. e f is the effective thickness of the fillet weld. f w h is the design strength value for the fillet weld. f This refers to the weld leg size for a fillet weld. Step 2: Process the reinforcing plate according to the specifications obtained in Step 1 to obtain the reinforcing plate; bevel the connection between the reinforcing plate and the steel column, and grind the connection between the reinforcing plate and the H-beam. Step 3: Clean the bottom of the upper flange of the H-beam, the top of the lower flange of the H-beam, and the outer flange of the steel column to obtain the H-beam and steel column to be reinforced. The cleaning involves using a hammer and an angle grinder to polish the fireproof and anti-corrosion coating at the connection between the H-beam and steel column and the reinforcement plate until the metal luster is exposed. The polishing length of the bottom of the upper flange and the top of the lower flange of the H-beam is the width of the reinforcement plate plus 80mm to 120mm. The polishing height of the outer flange of the steel column is the same as the height of the H-beam. Step 4: Mark the H-beams and columns to be reinforced obtained in Step 3; the marking points are located at the midpoint of the extended flange of the H-beam, and two reinforcing plates are symmetrically arranged on both sides of the web of the H-beam to be reinforced. Step 5: Install the two reinforcing plates obtained in Step 2 according to the positions marked in Step 4, and then weld the H-beams, steel columns and reinforcing plates. Step Six: Inspect the welds between the reinforced plate and the H-beam and steel column after welding in Step Five. Then, apply anti-corrosion coating and fireproof coating to the welded and cleaned areas in sequence to complete the reinforcement of the welding defects at the steel frame nodes.

2. The method for reinforcing weld defects at steel frame joints according to claim 1, characterized in that, The steel grade of the reinforcing plate mentioned in step two shall not be lower than that of the steel grade of the H-beam and steel column.

3. The method for reinforcing weld defects at steel frame joints according to claim 1, characterized in that, The welding rods used in step five are of the same grade as the lower grade of the steel used for the H-beams and columns.

4. The method for reinforcing weld defects at steel frame joints according to claim 1, characterized in that, The welding described in step five uses CO2 gas shielded welding. The three sides connecting the reinforcing plate to the H-beam and the steel column are first tack welded for positioning, and then the welding is continued to secure them. The weld connecting the reinforcing plate to the flange of the steel column is a full penetration single-sided V-groove weld. The weld connecting the reinforcing plate to the bottom of the upper flange of the H-beam and the top of the lower flange of the H-beam is a fillet weld.

5. The reinforcement method for welding defects in steel frame joints according to claim 4, characterized in that, The weld inspection process described in step six is ​​as follows: 24 hours after welding is completed, the weld appearance quality of the full penetration single-sided V-groove weld must meet the requirements of a first-class weld, the ultrasonic testing must meet the requirements of a second-class weld, and the appearance quality of the fillet weld must meet the requirements of a second-class weld.

6. The method for reinforcing weld defects at steel frame joints according to claim 1, characterized in that, The thickness of the anti-corrosion coating obtained by applying the anti-corrosion coating in step six shall not be less than 200 μm, and the thickness of the fireproof coating obtained by applying the fireproof coating shall be less than 2.5 mm when applying a thin or ultra-thin coating, and less than 30 mm when applying a thick coating.

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