CN115008053A - A kind of processing and manufacturing method of curved variable section steel box girder - Google Patents

Abstract

The invention discloses a processing and manufacturing method for a curved variable section steel box girder, which solves the technical problem of difficult control of the spatial alignment and the overall geometric dimension of the steel box girder in the prior art when it is manufactured in a factory. The invention decomposes the steel box girder into different plate units and processes them separately, and then assembles the processed plate units into the steel box beam by inverting assembly; Linked and cantilevered units. The invention is scientific and reasonable in design, and can effectively control the spatial alignment and overall geometric size of the steel box girder during factory manufacturing, so as to improve the manufacturing accuracy of the steel box girder, reduce the deformation during the welding process of the steel box girder, and disperse the welding internal stress. The steel box girder is processed by plate unit, and then the general assembly of the segments is carried out, which meets the requirements of the "Technical Specification for Highway Bridge and Culvert Construction" and realizes the linear control and processing accuracy of the steel box girder.

Description

A kind of processing and manufacturing method of curved variable section steel box girder

technical field

The invention belongs to the technical field of steel structure processing, and in particular relates to a processing and manufacturing method for a curved variable-section steel box girder.

Background technique

At present, the steel used in highway bridge construction in my country is remarkable, especially the steel structure box bridge, which has strong spanning ability, suitable for factory assembly and manufacturing, easy transportation, fast installation and construction speed, easy repair and replacement, high torsional rigidity, overall It has the characteristics of good performance and little impact on the environment during construction, so it is widely used. At present, steel box girders are used more and more in highway bridges in our country. How to control the spatial alignment and overall geometric size of steel box girders during factory manufacturing has become very difficult.

Therefore, designing a processing and manufacturing method of curved variable-section steel box girders to effectively control the spatial alignment and overall geometric dimensions of the steel box girders during factory manufacturing has become a technical problem to be solved urgently by those skilled in the art.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a processing and manufacturing method for a curved variable-section steel box girder, so as to solve at least some of the above-mentioned technical problems.

For achieving the above object, the technical scheme adopted in the present invention is as follows:

A method for processing and manufacturing a steel box girder with a variable cross-section of a curve. The steel box girder is decomposed into different plate units to be processed separately, and then the processed plate units are assembled into a steel box beam by an inverted assembly method; the plate unit includes a top plate unit, a bottom plate unit, Web elements, diaphragm elements, and cross-link and cantilever elements.

Further, assembling the steel box girder includes the following steps:

Step 1. Set up an inverted assembly tooling tire frame;

Step 2. Pave the roof unit on the inverted tooling frame;

Step 3. Assemble the partition unit on the top plate unit;

Step 4. Assemble the web unit on the top plate unit and the partition unit;

Step 5. Weld the top plate unit, the baffle plate unit and the web plate unit into one body to form a three-sided box;

Step 6. Set up a positive assembly tooling tire frame;

Step 7. Lay the bottom plate unit on the assembling tooling frame;

Step 8. Assemble the three-sided box to the bottom plate unit to form a four-sided box;

Step 9. Assemble the horizontal and cantilever units to the square box;

Step 10. Assemble the roof shear key on the square box to form the steel box girder.

Further, in the step 1, when erecting the inverted assembling tooling frame, H350*150*20*20H steel is used as the material to construct the inverted assembling tooling frame, and the inverted assembling tooling frame needs to be installed on the hardened ground. , The column of the inverted-assembled tooling frame is made of T-shaped steel, and is connected by scissors to ensure the strength and stability of the inverted-assembled tooling frame; The line type of the bottom plate should be consistent, and the line type of each fulcrum should be consistent with the longitudinal and transverse slopes and pre-camber values of the steel box girder; the vertical and horizontal baselines and reference points should be set for the inverted assembly tooling frame, and its peripherals should be equipped with independent benchmarks Lines and reference points; after the erection of the inverted assembly tooling tire frame, the overall connection elevation should be measured and the measured data should be archived to ensure that the line type is consistent with the drawing and completely correct before the roof unit can be laid; before each assembly assembly All of them should be tested for the inverted assembly tooling tire frame, and the test record should be made, and the next assembly can be carried out only after passing the test;

In the step 6, when erecting the positive-assembling tooling frame, the positive-assembling tooling frame is erected on the hardened ground, and the positive-assembling tooling frame column adopts T-shaped steel and is connected with scissors to form a whole to ensure the strength of the positive-assembling tooling frame and stability.

Further, in the step 2, when the top plate unit is installed on the inverted tooling frame, the top plate unit needs to be corrected to completely fit with the inverted tooling frame in a natural state, and it is forbidden to use spot welding and wedge code methods to force the top plate. The unit and the reverse tooling frame are fitted; during the process, precise measurement is required to control the positioning accuracy of the roof unit paving. The roof unit cannot be offset in the direction of the bridge. When the offset occurs, the positioning of the roof unit needs to be adjusted immediately to ensure The longitudinal centerline of each roof element is parallel to the bridge centerline.

Further, in the step 7, when the base plate unit is paved on the assembling tooling frame, the base plate unit is fabricated on the assembling tooling frame, and the base plate rib is welded symmetrically with automated equipment to control the welding deformation, and the base plate is welded. After the unit is welded and calibrated to the natural state, it needs to be completely fitted with the frame of the assembling tooling. It is forbidden to use spot welding and wedge coding to force the base unit and the frame of the assembling tooling to fit.

Further, the baffle unit is fabricated on the platform, the web unit is fabricated on the web tooling, and the baffle rib of the baffle unit and the web rib of the web unit are welded symmetrically using automated equipment to control welding deformation. , and after each welding, it needs to be corrected before it can be transferred to the next process. The diaphragm unit and the web unit are checked with a hanging wire hammer to ensure that the diaphragm and the web plumb weight are on the ground;

In the step 5, when the top plate unit, the baffle plate unit and the web plate unit are welded into one body, first the baffle plate unit and the web plate unit are vertically welded, and then the baffle plate unit and the top plate unit are flat-welded and welded symmetrically. In order to control the welding deformation; according to the height of the web unit of each section, the partition unit and the web unit are vertically welded in the length direction of the bottom unit to reserve 1-2 meters without welding, and the three-sided box will be placed on the assembling tooling frame. After the assembly with the base plate unit is completed, the welding is carried out;

In the step 10, after assembling the roof shear key on the square box to form the steel box girder; the steel box girder needs to be corrected, drilled with bolt holes, the connecting plate is precisely positioned with punching nails, and pressed with ordinary bolts Then drill the box.

Further, the processing board unit method is carried out according to the following steps:

Step (1), lofting, splicing, and cutting the processing materials, and welding seam inspection is required during the process;

Step (2): Paying off the processed plate unit and grinding the parts while welding;

Step (3), assembling the spot welding plate rib, and the welding seam flaw detection inspection is required in the process;

Step (4), the plate unit is welded, and the welding seam inspection is required during the process;

Step (5), the plate unit is corrected, and that's it.

Further, when the roof unit is processed according to the method of processing the plate unit, the material for processing the roof unit is 12mm thick steel plate and 22mm thick steel plate, and the 22mm thick steel plate is used at the web line of the main girder along the bridge and the transverse connection of the transverse bridge. All parts are made of 12mm thick steel plates; the roof unit includes vertical and horizontal joints with a thickness of 22mm and steel formwork with a thickness of 12mm. When cutting materials, the vertical and horizontal joints mark the web positioning line with a foreign punch to ensure that the adjacent steel box girder box webs There is no wrong side of the unit; when cutting, the vertical and horizontal links are not beveled, and the 12mm steel formwork is beveled; when blanking, the vertical and horizontal links and steel formwork are separately blanked, and then spliced. When splicing, the two sides are spliced to ensure the top plate Flatness and reduce welding deformation caused by the welding seam of roof unit;

The web unit includes a web and a rib. The height of the web section is 3m-6m. When the web unit is processed according to the method of processing the panel unit, the blanking of the web unit is carried out according to the length of each tooling. Punch out the punch hole of the baffle unit to facilitate the assembly and positioning of the baffle unit. The web unit is provided with a 40-degree outer groove, leaving no blunt edges; the web of a tooling position is a whole section during processing, and it is cut after welding is completed. Several web segments are opened, and each web segment is drilled on one side in advance to reduce the amount of drilling holes in the air; the assembly, welding and correction of the web unit are consistent with the roof unit.

Further, the clapboard unit includes a clapboard panel, longitudinal and transverse stiffening ribs, and manhole ring stiffening ribs. When the clapboard unit is processed according to the method of processing the clapboard unit, the clapboard panel is placed on the flat tooling surface and the robot is used according to the first steps. After the vertical seam, the flat seam and the symmetrical welding principle from the middle to both sides are used for welding to reduce the welding deformation. When the plate thickness of the longitudinal and transverse stiffening ribs and the manhole ring stiffening ribs is greater than 16mm, the partial penetration of the open groove is adopted. For welds, ordinary fillet welds shall be adopted when the plate thickness of longitudinal and transverse stiffening ribs and manhole ring stiffening ribs is less than or equal to 16mm;

The baffle panel is provided with baffle stiffening ribs on both sides, and the baffle stiffening rib is at the free shrinkage end. After welding, there will be different degrees of warpage deformation around the four sides, and the baffle panel needs to be corrected for flatness; When rectifying, a combination of flame rectification and mechanical rectification should be used for rectification. For the partial bubbling part in the middle of the clapboard panel, the uniformly distributed point flame rectification method of "plum blossom" is used for rectification;

When the base plate unit is processed according to the method of processing the plate unit, the base plate unit includes the main beam base plate unit and the standard section base plate unit. When cutting the material, the positioning line of the web plate unit needs to be marked, and the longitudinal stiffeners of the arc-shaped base plate unit are cut by numerical control. Drill holes at both ends of the longitudinal stiffeners of the bottom plate unit, and the connecting plate of the bottom plate unit is marked and drilled; the bottom plate unit is a slat rib, and a codeless assembly equipment is used to assemble multiple slat ribs at the same time. Welding is carried out on the welding frame, using automatic slat rib welding equipment for welding, and rectification after welding is completed;

The main girder base plate unit is leveled by flame rectification on the tooling platform that has been super flat, and the back of the base plate unit at the corresponding part of the slat rib weld is subjected to baking stress relief treatment, and a 2-meter-long aluminum alloy plate ruler is used for leveling. After the main girder floor unit is checked for flatness; longitudinally, the floor unit is welded and the tire frame is erected for inspection and correction.

Further, during the processing of the plate unit, the steel plate is leveled by a leveling machine, and the whole production line of pretreatment is used to remove rust on the surface of the steel plate and spray the shop primer, and the rust removal level reaches Sa2.5; The multi-head straight strip cutting machine draws straight strips to ensure the blanking accuracy, and the holes are made by CNC plane drilling;

The plate unit is assembled on the assembled tire frame and the edge and end of the plate are used as the positioning reference. Before assembly, the curve coordinates are given in the sample drawing to connect the curve point by point and draw the diaphragm on the top, bottom and web units. Locate the center line, draw the spacing of each rib locating line on the top plate, draw the rib locating point on the passing point of the diaphragm, and draw the web locating edge on the center line between the two diaphragms Mark the sections with foreign punches, control the positioning accuracy of the top and bottom web units to ensure that the longitudinal centerline of each floor unit is parallel to the bridge centerline, control the flatness of the diaphragm and the reinforcement ring after assembly and welding, and the plate ribs The assembly size deviation of the board unit should be controlled within the specification;

When the plate unit is processed and welded, remove the rust, oxide scale, oil stain and steel plate pretreatment workshop primer in the area to be welded before assembling and welding. The cleaning range on both sides of the welding bead is not less than 30mm. , The welding area should be welded within 5 hours after the welding seam is polished under the condition of high humidity in the welding area. The welding environment temperature should not be lower than 0 °C, and the humidity should be less than 80%. During welding, it is strictly forbidden to start welding in the non-welding area of the base metal. After welding Remove slag and spatter in time. Continuous welding and control the temperature between layers are required for multi-layer welding. After each layer of weld is welded, remove the coating, slag and overflow in time before welding the next layer; butt joint welding Both ends of the seam need to be equipped with arc ignition plates and arc quenching plates. After welding, flame cutting is used to remove the arc ignition and quenching plates and grind them flat;

After the plate unit is processed and welded, it needs to be rectified by a combination of flame rectification and mechanical rectification. The partial bubbling in the middle of the panel is rectified with a "plum blossom" uniformly distributed point flame. The heating temperature during thermal rectification is 600~ 800 ℃, the temperature of the parts should be slowly cooled after correction, and quenching with water should not be used.

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

The invention is scientific and reasonable in design, and can effectively control the spatial alignment and overall geometric size of the steel box girder during factory manufacturing, so as to improve the manufacturing accuracy of the steel box girder, reduce the deformation during the welding process of the steel box girder, and disperse the welding internal stress. The steel box girder is processed by plate unit, and then the general assembly of the segments is carried out, which meets the requirements of the "Technical Specification for Highway Bridge and Culvert Construction" and realizes the linear control and processing accuracy of the steel box girder.

Description of drawings

Fig. 1 is a flow chart of a method for manufacturing a curved variable-section steel box girder according to the present invention.

FIG. 2 is a flow chart of the processing method of the board unit according to the present invention.

3 is a schematic cross-sectional view of the steel box girder of the present invention.

Fig. 4 is a schematic diagram of the plate rib unit of the present invention.

FIG. 5 is a schematic diagram of a 22mm longitudinally combined 12mm template of the present invention.

FIG. 6 is a schematic diagram of a standard section base plate unit of the present invention.

FIG. 7 is a schematic diagram of the main beam base plate unit of the present invention.

FIG. 8 is a schematic diagram of the marking of the positioning line of the web of the present invention.

FIG. 9 is a schematic diagram of the base plate unit of the present invention.

Figure 10 is a schematic diagram of the web unit of the present invention.

FIG. 11 is a schematic diagram of the erection of the inverted assembling tooling frame according to the present invention.

FIG. 12 is a schematic diagram of the top plate unit being installed on the inverted-assembled tooling frame according to the present invention.

FIG. 13 is a schematic diagram of the assembly of the partition unit of the present invention.

Figure 14 is a schematic diagram of the web unit assembly of the present invention.

Figure 15 is a schematic diagram of the welding of the partition plate, the web plate and the top plate according to the present invention.

FIG. 16 is a schematic diagram of the erection of the assembling tool tire frame according to the present invention.

Fig. 17 is a schematic diagram of paving the base plate unit on the assembling tooling frame according to the present invention.

FIG. 18 is a schematic diagram of the assembly of the square box of the present invention.

FIG. 19 is a schematic diagram of horizontal connection and cantilever assembly of the present invention.

Fig. 20 is a schematic diagram of assembling the top plate shear key according to the present invention.

Fig. 21 is the diagram example 1 of the allowable deviation of the assembly size of the plate rib of the present invention.

Figure 22 is a diagram 2 of the allowable deviation of the assembly dimension of the plate rib of the present invention.

Fig. 23 is the diagram example 1 of the allowable deviation of the assembly size of the diaphragm unit of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

As shown in Figs. 1-8, the present invention provides a method for processing and manufacturing a steel box girder with variable cross-section, which is scientific and reasonable, and can effectively control the spatial alignment and overall geometric dimensions of the steel box girder during factory manufacturing, so as to improve the The manufacturing accuracy of steel box girder can reduce the deformation of steel box girder during welding, disperse welding internal stress, adopt plate element processing for steel box girder, and then carry out the general assembly of segments, which meets the requirements of "Technical Specification for Highway Bridge and Culvert Construction" at the same time. Realize the linear control and machining accuracy of steel box girder. The invention decomposes the steel box girder into different plate units and processes them separately, and then assembles the processed plate units into the steel box girder in a reverse assembly manner; Linked and cantilevered units. Assembling the steel box girder includes the following steps:

Step 1. Set up an inverted assembly tooling tire frame;

Step 2. Pave the roof unit on the inverted tooling frame;

Step 3. Assemble the partition unit on the top plate unit;

Step 4. Assemble the web unit on the top plate unit and the partition unit;

Step 5. Weld the top plate unit, the baffle plate unit and the web plate unit into one body to form a three-sided box;

Step 6. Set up a positive assembly tooling tire frame;

Step 7. Lay the bottom plate unit on the assembling tooling frame;

Step 8. Assemble the three-sided box to the bottom plate unit to form a four-sided box;

Step 9. Assemble the horizontal and cantilever units to the square box;

Step 10. Assemble the roof shear key on the square box to form the steel box girder.

In the step 1 of the present invention, when erecting the inverted-assembled tooling frame, H350*150*20*20H steel is used as the material to construct the inverted-assembled tooling frame, and the inverted-assembled tooling must be installed on the hardened ground. The column of the inverted assembling tooling frame is made of T-shaped steel and connected by scissors to ensure the strength and stability of the inverted assembling tooling frame; The line type should be consistent, and the line type of each fulcrum connection should be consistent with the longitudinal and lateral slope and pre-camber values of the steel box girder; the vertical and horizontal baselines and reference points should be set for the inverted assembling tooling frame, and its peripheral independent reference line should be set. and the reference point; after the erection of the inverted assembly tooling tire frame, the overall connection elevation should be measured and the measured data should be archived to ensure that the line type is consistent with the drawing and completely correct before the roof unit can be laid; The inverted assembly tooling tire frame should be inspected, and the inspection record should be made. After passing the test, the next assembly can be carried out.

In the step 6 of the present invention, when erecting the positive-assembling tooling tire frame, the positive-assembling tooling tire frame is erected on the hardened ground, and the positive-assembling tooling tire frame column adopts T-shaped steel and is connected with scissors to form a whole to ensure the positive-assembling tooling tire frame strength and stability.

In the step 2 of the present invention, when the top plate unit is installed on the inverted tire frame, the top plate unit needs to be corrected to completely fit with the inverted tire frame in a natural state, and it is prohibited to use spot welding and wedge coding to force the top plate unit. Fitting with the reverse tooling tire frame; precise measurement is required in the process to control the positioning accuracy of the roof unit paving. The roof unit cannot be offset in the direction of the bridge. When deviation occurs, the positioning of the roof unit needs to be adjusted immediately to ensure that every The longitudinal centerline of the block roof element is parallel to the bridge centerline.

In the step 7 of the present invention, when the base plate unit is installed on the assembling tool frame, the base plate unit is fabricated on the assembling tool frame, and the base plate rib is welded symmetrically with automatic equipment to control welding deformation, and the base plate unit is welded. After the welding is completed and corrected to the natural state, it must be completely fitted with the frame of the assembling tooling. It is prohibited to use spot welding and wedge coding to force the bottom plate unit and the frame of the assembling tooling to fit.

The separator unit of the invention is fabricated on the platform, the web unit is fabricated on the web tooling, the separator rib of the separator unit and the web rib of the web unit are welded symmetrically by automated equipment to control the welding deformation, And after each welding, it needs to be corrected before it can be transferred to the next process. Both the diaphragm unit and the web unit are checked with a hanging wire hammer to ensure that the diaphragm and the web are plumb on the ground.

In the present invention, in the step 5, when the top plate unit, the baffle plate unit and the web plate unit are welded into one body, the baffle plate unit and the web plate unit are first welded vertically, and then the baffle plate unit and the top plate unit are flat-welded, and symmetrically Welding is performed to control the welding deformation; according to the height of the web unit of each section, the vertical welding of the bulkhead unit and the web unit is reserved for 1-2 meters in the length direction of the bottom plate unit without welding, and the three-way The box body and the bottom plate unit are assembled and then welded.

In the present invention, in the step 10, after assembling the roof shear key on the square box to form the steel box girder; the steel box girder needs to be calibrated and drilled with bolt holes. After pressing, drill the box body.

The method of processing the plate unit of the present invention is carried out according to the following steps:

Step (1), lofting, splicing, and cutting the processing materials, and welding seam inspection is required during the process;

Step (2): Paying off the processed plate unit and grinding the parts while welding;

Step (3), assembling the spot welding plate rib, and the welding seam flaw detection inspection is required in the process;

Step (4), the plate unit is welded, and the welding seam inspection is required during the process;

Step (5), the plate unit is corrected, and that's it.

When the present invention processes the roof unit according to the method of processing the plate unit, the material for processing the roof unit adopts the 12mm thick steel plate and the 22mm thick steel plate, and the 22mm thick steel plate is used at the web line of the main girder along the bridge direction and the transverse joint in the transverse bridge direction. 12mm thick steel plates are used; the top plate unit includes vertical and horizontal joints with a thickness of 22mm and steel formwork with a thickness of 12mm. When cutting materials, the vertical and horizontal joints mark the web positioning line with Yang Chong to ensure the adjacent steel box girder box web plate unit There is no wrong side situation; when cutting, the vertical and horizontal links are not beveled, and the 12mm steel formwork is beveled; when blanking, the vertical and horizontal links and steel formwork are separately blanked, and then spliced. When splicing, the two sides are spliced to ensure that the top plate is flat and reduce the welding deformation caused by the welding seam of the roof unit.

The web unit of the present invention includes a web and a rib, and the height of the web section is 3m-6m. When the web unit is processed according to the method of processing the panel unit, the blanking of the web unit is performed according to the length of each tooling division, and the web unit is cut. The foreign punch holes of the baffle unit are punched both inside and outside to facilitate the assembly and positioning of the baffle unit. The web unit is provided with a 40-degree outer groove without leaving a blunt edge; the web of a tooling position is a whole section during processing, and the welding is completed after the completion. Several web segments are cut and disconnected, and each web segment is drilled on one side in advance to reduce the amount of drilling in the air; the assembly, welding and correction of the web unit are consistent with the roof unit.

The baffle unit of the invention includes baffle panels, longitudinal and transverse stiffening ribs, and manhole ring stiffening ribs. When the baffle unit is processed according to the method of processing the baffle unit, the baffle panel is placed on a flat tooling surface, and a robot is used to erect the baffle unit according to the first method. After the seam, the welding is carried out on the principle of flat seam and symmetrical welding from the middle to both sides to reduce the welding deformation. When the plate thickness of the longitudinal and transverse stiffening ribs and the manhole ring stiffening ribs is greater than 16mm, partial penetration welding with open grooves is adopted. When the plate thickness of longitudinal and transverse stiffening ribs and manhole ring stiffening ribs is less than or equal to 16mm, ordinary fillet welds shall be adopted.

The baffle panel of the invention is provided with baffle stiffening ribs on both sides, and the baffle stiffening rib is at the free shrinkage end. After welding, the four peripheries will be warped and deformed to varying degrees, and the baffle panel needs to be corrected for flatness; When the plate unit is rectified, a combination of flame rectification and mechanical rectification is adopted. For the partial bubbling part in the middle of the baffle panel, the uniformly distributed point flame rectification method of "plum blossom" is used for rectification.

When the present invention processes the base plate unit according to the method of processing the plate unit, the base plate unit includes the main beam base plate unit and the standard section base plate unit. When cutting the material, the positioning line of the web plate unit needs to be marked, and the longitudinal stiffeners of the arc-shaped base plate unit are processed by numerical control. materials, drill holes at both ends of the longitudinal stiffeners of the bottom plate unit, and carry out marking and drilling on the connecting plate of the bottom plate unit; the bottom plate unit is a slat rib. Welding is carried out on the anti-deformation welding frame, and welding is carried out by automatic slat rib welding equipment. After the welding is completed, the correction treatment is carried out.

The main girder base plate unit of the present invention is leveled by flame rectification on the tooling platform that has been super-flat processed, and the back of the base plate unit at the corresponding part of the slat rib weld is subjected to baking stress relief treatment, and a 2-meter-long aluminum alloy plate ruler is used to After leveling, the main beam floor unit is checked for flatness; longitudinally, the floor unit is welded and the tire frame is installed for inspection and correction.

During the processing of the plate unit of the present invention, the steel plate is leveled by a leveling machine, and the whole production line of pretreatment is used to remove rust on the surface of the steel plate and spray the shop primer, and the rust removal grade reaches Sa2.5; The straight strip cutting machine draws straight strips to ensure the blanking accuracy, and the holes are made by CNC plane drilling.

The plate unit of the present invention is assembled on the assembled tire frame and uses the edge and end of the plate as the positioning reference. Before assembly, the curve is connected point by point according to the curve coordinates given in the sample drawing, and horizontal lines are drawn on the top, bottom and web units. Clapboard positioning center line, draw the spacing of each rib positioning line on the top plate, draw the plate rib positioning point on the passing point of the transverse partition, and draw the web positioning edge at the point between the two transverse partitions and its center Mark the sections on the line with foreign punches, control the positioning accuracy of the top and bottom web units to ensure that the longitudinal centerline of each floor unit is parallel to the bridge centerline, and control the flatness of the diaphragm and the reinforcement ring after assembly and welding. For the plate and rib unit, samples must be made to check the assembly size deviation, and the assembly size must be controlled within the specification. The allowable deviation of the sample size of the plate and rib unit is shown in Table 1.

Table 1 The allowable deviation of the sample size of the plate rib unit

serial number project Allowable deviation (mm) 1 diagonal 1.0 2 Distance between parallel lines and segment size ±1.0 3 width, length +0.5～-1.0 4 The angle of the processing template ±10’ 5 Any point deviation on the curve template 1.0

When the plate unit of the present invention is processed and welded, the rust, oxide scale, oil stain and steel plate pretreatment workshop primer in the area to be welded should be removed before assembly and welding, and the cleaning range on both sides of the welding bead is not less than 30mm. For internal welding, the welding area should be welded within 5 hours after the welding seam is polished under the condition of high humidity in the welding area. The welding environment temperature should not be lower than 0 °C and the humidity should be less than 80%. During welding, the welding arc is strictly prohibited in the non-welding area of the base metal. After welding, remove slag and spatter in time. When multi-layer welding, it is necessary to continuously weld and control the temperature between layers. After each layer of weld is welded, remove the coating, slag, and overflow in time, and then weld the next layer; Both ends of the welding seam of the joint shall be provided with arc ignition plates and arc quenching plates. After welding, the arc ignition and quenching plates shall be removed by flame cutting and smoothed.

The panel unit of the present invention needs to be rectified after processing and welding, and it is carried out by a combination of flame rectification and mechanical rectification. The partial bubbling in the middle of the panel adopts the uniformly distributed point-like flame rectification method of "plum dots". 600 ~ 800 ℃, the temperature of the parts should be slowly cooled after correction, and quenching with water should not be used. The allowable deviation of parts correction is shown in Table 2; the allowable deviation of the plate rib assembly size is shown in Table 3, the letters in the table are shown in Figure 21 and Figure 22; the allowable deviation of the assembly size of the diaphragm unit is shown in Table 4, and the letters in the table are shown in Table 4. Figure 23; The allowable deviation of assembly dimensions of other parts is shown in Table 5.

Table 2 Parts Correction Allowable Deviation (mm)

Table 3. Allowable deviation of plate rib assembly size (mm)

Table 4. Allowable deviation of assembly size of diaphragm unit (mm)

Table 5 Allowable deviation of assembly dimensions of other parts (mm)

The tooling frame of the invention has high production precision, and the tooling frame itself has sufficient strength and stability to meet the assembly requirements of steel box beams and steel box beams. The line type of the box girder bottom plate remains the same. The line type of each fulcrum connection takes into account the longitudinal, transverse slope and pre-camber values of the steel box girder. After the tooling tire frame is erected, the overall connection elevation is measured to ensure that the line type is consistent with the drawing, and the floor unit is completely correct behind. Vertical and horizontal baselines and reference points are set on the tire frame; independent reference lines and reference points are set outside the tire frame. The tire frame is tested before each assembly, and the inspection record is made. After confirming that it is qualified, the next assembly is carried out; each tire frame elevation takes into account the influence caused by the vertical curve of the bridge and the pre-camber.

The box diaphragm of the invention has high machining accuracy, including peripheral geometric size, adjacent side angle control and longitudinal plate rib slot position accuracy control. The flatness after assembly and welding with the reinforcing ring, the flatness of the diaphragm can not be assembled after the flatness is unqualified.

The top, bottom and web units of the invention have high blanking precision, and the curves are connected point by point according to the curve coordinates given in the detailed drawing, and the positioning center line of the transverse partition is drawn on the bottom and the web, and the top plate is on the transverse partition. The rib positioning points are drawn on the plate passing points to prevent the center of the diaphragm from being inconsistent with the center of the longitudinal rib on the top plate. Between the two transverse partitions, the positioning edge of the web should be drawn at multiple points, and the centerline should be marked with a punch.

The invention has high positioning accuracy for the paving of the roof unit. When laying the floor unit, it can be accurately measured at any time, and the positioning accuracy of the roof unit paving is strictly controlled. When there is an offset, the positioning of the slab units needs to be adjusted immediately to ensure that the longitudinal centerline of each roof slab unit is parallel to the bridge centerline.

The quality control measures of the board unit of the present invention

The control of the steel plate and the plate rib pretreatment of the present invention. Control measures: The steel plate is leveled by a leveling machine to ensure the flatness of the plate surface; the whole production line of pretreatment is used to remove rust on the surface of the steel plate and spray shop primer, and the rust removal level reaches Sa2.5.

The invention controls the blanking and numerical control cutting precision. Control measures: Parts are cut by plasma numerical control, and the slats are cut by a multi-head straight cutting machine to ensure the cutting accuracy; CNC plane drilling is used for hole making; strips, plasma cutting special-shaped plates and holes must be qualified first inspection After batch processing.

The control of the assembly precision of the board unit of the present invention. Control measures: 1) The board unit should be assembled on the assembled tire frame, and the assembled tire frame should be checked before each assembly, and it can be assembled after confirming that it is qualified; sub-cut head end) as the positioning reference. 2) Before assembly, the curve should be connected point by point in strict accordance with the curve coordinates given in the detailed drawing, and the positioning center line of the diaphragm should be drawn on the top, bottom and web plates, and the positioning lines of each plate rib should be drawn on the top plate. The spacing error should not be too large, and the positioning point of the plate rib must be drawn on the point where the diaphragm passes through to prevent the center of the diaphragm from being inconsistent with the center of the longitudinal plate rib on the top plate. The positioning edge of the web should be drawn at multiple points between the two transverse partitions, and the centerline should be marked with a punch. 3) Strictly control the positioning accuracy of the top and bottom web unit paving, especially the positioning along the bridge direction, and no large deviation can occur. When deviation occurs, the positioning of the plate unit must be adjusted immediately to ensure that each The longitudinal centerline is parallel to the bridge centerline. 4) The diaphragm unit shall strictly control the peripheral geometric dimensions, the included angle of adjacent sides, and the position accuracy of the longitudinal plate rib notch, and control the flatness of the diaphragm and the reinforcement ring after assembly and welding. The flatness is unqualified. The diaphragm needs to be rectified and qualified before it can be assembled. 5) For the plate and rib units, samples must be made to check the assembly size deviation, the assembly size must be controlled within the specification, and the allowable deviation of the sample size is shown in Table 1.

The present invention controls the welding quality of the board unit. 1) The welding process documents should be strictly implemented during welding, and the quality inspector should check the implementation of the welding process documents. 2) Before the assembly of the plate unit, the rust, oxide scale, oil stain, steel plate pretreatment and shop primer must be thoroughly removed from the area to be welded. 3) The main components should be welded within 24 hours after assembly. If the time is exceeded, the welding parts can be cleaned or dehumidified according to the actual situation. For the overall assembly of the beam section and the welding seam on the bridge, due to the high ambient humidity, the welding area is easy to rust. The welded seam after grinding should be welded in time, and the interval should not be greater than 5h. 4) The welding work should be carried out indoors or in a wind and rainproof facility. The ambient temperature for welding low alloy steel should not be lower than 5°C, for ordinary carbon steel welding should not be lower than 0°C, and the humidity in the welding environment should be less than 80%. When the above requirements cannot be met, the necessary technological measures and protective measures shall be taken before welding. 5) When welding, the non-welded parts of the base metal are strictly prohibited from welding arc, and the slag and spatter should be removed in time after welding. In multi-layer welding, continuous welding should be performed, and the temperature between layers should be controlled. After each layer of welds is welded, it should be cleaned and inspected in time. After removing the coating, slag, overflow and other defects, the next layer should be welded. 6) For the welding seam of the butt joint, the arc striking plate and the arc quenching plate must be set at both ends, and the material and groove form should be the same as the workpiece to be welded. After welding, use flame cutting to remove the arc-quenching plate, and grind it flat, and it is strictly forbidden to use a hammer to knock it down. 7) Welding should be carried out with automatic equipment as much as possible. When special parts cannot be welded by automatic equipment, two-protection welding can be used. Second-protection welding shall select certified welders and welders with strong technical ability for welding operations.

The invention controls the welding deformation and correction of the plate unit. 1) Welding deformation control measures, ① Selecting and controlling a reasonable welding sequence is an effective measure to prevent welding stress and one of the most effective methods to prevent welding deformation. According to different welding methods, different welding sequences are formulated. Submerged arc welding generally adopts reverse method and step-back method; CO ₂ gas shielded welding and manual welding adopt symmetrical method and uniform dispersion method; Symmetrical, uniform and less restrictive". ②The anti-deformation of the plate unit controls the welding deformation. The main girder web and the bottom plate unit plate rib are welded, and the welding is carried out on the anti-deformation tire frame, and the anti-deformation tire frame can effectively control the deformation caused by welding. ③The deformation after butt welding of thick plates is mainly corner deformation. When welding thick plates, first weld a part of the weld bead on the front side, turn the workpiece, carbon planer and clean the root, and then weld the weld bead on the reverse side, and then turn the workpiece, and so on and so forth until the front side is fully welded. of each weld. At the same time, it is necessary to observe the angular deformation at any time during welding, and pay attention to be ready to turn over and weld at any time, so as to reduce the welding deformation and the internal stress of the weld as much as possible. ④ In the case of many welds of complex components, according to the shape of the components and the layout of the welds, the welds with larger shrinkage should be welded first, and the welds with smaller shrinkage should be welded later; Free shrinkable welds and welds with less restraint after welding and free shrinkage to achieve the purpose of reducing welding stress.

2) Correction control measures: ① The correction of the panel unit is mainly carried out by the combination of flame correction and mechanical correction. For the partial bubbling in the middle of the panel, the uniform point flame correction method of "plum blossom point" can be adopted. ②There should be no dents and other damages on the surface of the corrected plate element and beam section. When hammering is used for local trimming, pads must be added, and the components shall not be directly hammered. ③ When using hot straightening, the heating temperature should be controlled at 600 ~ 800 ℃, and overheating is strictly prohibited. After correction, the temperature of the parts should be slowly cooled, and the steel should not be hammered or quenched with water before the temperature drops to room temperature. See Table 2 for the allowable deviation of components.

The overall appearance of the panel unit of the present invention is controlled. Strictly carry out welding operations in accordance with the welding process evaluation to reduce welding deformation; for plate rib plate units, use plate rib no-code assembly equipment to assemble multiple plate ribs at the same time to reduce the appearance defects of welding scar grinding; non-welded parts of the base metal during welding Welding arc ignition is strictly prohibited; after each process group welding, the coating, slag, spatter, overflow, welding scar, porosity, undercut and other appearance defects should be removed in time.

The size of the board unit of the present invention allows deviation. (1) The allowable deviation of the assembly dimensions of the plate and rib units (including the main girder bottom plate and the web plate unit) shall comply with Table 3. (2) The allowable deviation of the assembly size of the steel box girder segment assembled diaphragm unit shall comply with the requirements in Table 4. (3) The allowable deviation of assembly dimensions of other parts shall comply with the provisions in Table 5.

The manufacturing process of the steel box girder of the present invention, in order to ensure its welding quality, the assembly method of the steel box girder segment adopts the "reverse assembly" method, and the assembly process is as follows:

1. Set up the reverse tooling tire frame. H350*150*20*20H steel is used to erect the tooling, the tooling is erected on the hardened ground, the tooling column is made of T-shaped steel, and is connected with scissors to form a whole to ensure sufficient strength and stability of the tooling; after the tooling is erected, it must be reported for quality Inspection and acceptance, the measured data is archived.

2. Roof unit paving. The roof unit must be calibrated to fully fit with the tooling in the natural state. It is forbidden to forcibly fit the roof and tooling by spot welding, wedge code, etc.; fit the situation.

3. Partition unit assembly. The baffle unit is made on the platform, and the baffle rib is welded symmetrically with automatic equipment to control the welding deformation. After the welding is corrected, it can be transferred to the next process; on the earth.

4. Web unit assembly. The web unit is made on the web tooling, and the web rib is welded symmetrically with automatic equipment to control the welding deformation. After the welding is corrected, it can be transferred to the next process; A plumb bob on the earth.

5. Weld the partition plate with the web plate and the top plate. The welding sequence is: vertical welding of the partition plate and the web plate first, flat welding between the partition plate and the top plate, and symmetrical welding to control the welding deformation; Leave 1-2 meters without welding, and then weld after the three-sided box and the bottom plate are assembled on the positive tooling. (Note: The cantilever and horizontal links in the picture are assembled during formal installation)

6. Pre-assembled formal tire frame erection. The tooling is erected on the hardened ground, and the tooling column is made of T-shaped steel and connected with scissors to form a whole to ensure sufficient strength and stability of the tooling;

7. Floor unit paving. The bottom plate unit is made on the positive tooling. When the bottom plate rib is welded, it is symmetrically welded with automatic equipment to control the welding deformation. After welding, it is corrected to the natural state and fully fitted with the tooling. It is forbidden to use spot welding, wedge code, etc. fit.

8. Square box assembly.

9. Horizontal and cantilever assembly. After the assembly is completed, report to quality inspection and inspection, section size, box line shape, fit with tooling, etc., and welding can be performed after passing the test.

10. Assemble the top plate shear key.

11. Correction and drilling of bolt holes. The connecting plate is precisely positioned by punching nails, and the box body is drilled after being pressed with ordinary bolts.

Finally, it should be noted that the above embodiments are only preferred embodiments of the present invention to illustrate the technical solutions of the present invention, not to limit them, and certainly not to limit the patent scope of the present invention; although referring to the foregoing embodiments The present invention has been described in detail, and those of ordinary skill in the art should understand that: it is still possible to modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements to some or all of the technical features; and these modifications or replacements , does not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present invention; that is to say, any change or embellishment made in the main design idea and spirit of the present invention that has no substantial meaning, it solves the problem. If the technical problem is still consistent with the present invention, it shall be included in the protection scope of the present invention; in addition, the direct or indirect application of the technical solution of the present invention in other related technical fields shall be similarly included in the patent of the present invention within the scope of protection.

Claims (10)

1. A method for processing and manufacturing a curved variable cross-section steel box girder is characterized in that the steel box girder is decomposed into different plate units to be processed respectively, and the processed plate units are assembled into the steel box girder in an inverted assembling mode; the plate unit comprises a top plate unit, a bottom plate unit, a web plate unit, a partition plate unit, a transverse connection unit and an overhanging unit.

2. The method for processing and manufacturing the curved variable-section steel box girder according to claim 1, wherein the assembling of the steel box girder comprises the following steps:

step 1, erecting an inverted assembly tooling jig frame;

step 2, paving a top plate unit on the inverted tooling jig frame;

step 3, assembling partition plate units on the top plate units;

step 4, assembling web plate units on the top plate unit and the partition plate unit;

step 5, welding the top plate unit, the partition plate unit and the web plate unit into a whole to form a three-side box body;

step 6, erecting a positive assembling tooling jig frame;

step 7, paving a bottom plate unit on the assembling tooling jig frame;

step 8, assembling the three-side box body to the bottom plate unit to form a square box body;

step 9, assembling the transverse connection and cantilever units to the square box body;

and 10, assembling a top plate shear key on the square box body to form the steel box beam.

3. The method for processing and manufacturing the curved variable-cross-section steel box girder according to claim 2, wherein in the step 1, when the inverted assembly tooling jig frame is erected, H350X 150X 20H-shaped steel is used as a material for erecting the inverted assembly tooling jig frame, the inverted assembly tooling jig frame is erected on a hardened ground, and upright columns of the inverted assembly tooling jig frame are made of T-shaped steel and are connected into a whole by using a shear support to ensure the strength and stability of the inverted assembly tooling jig frame; the line type of the connecting line of each supporting upright post fixed point of the inverted assembly tooling jig frame needs to be consistent with the line type of a steel box girder bottom plate, and the line type of the connecting line of each fulcrum needs to be consistent with the longitudinal and transverse gradients and the pre-camber numerical value of the steel box girder; the inverted assembly tooling jig frame is required to be provided with a longitudinal baseline, a transverse baseline and a datum point, and an independent datum line and a datum point are arranged outside the inverted assembly tooling jig frame; after the inverted assembly tooling jig frame is erected, the integral connection line elevation of the inverted assembly tooling jig frame needs to be measured and actual measurement data is filed, so that the top plate unit can be laid after the line type is consistent with a drawing and is completely correct; before each assembling, the inverted assembling tooling jig frame is detected, detection records are made, and the next assembling can be carried out after the assembly is qualified;

in the step 6, when the assembling tooling jig frame is erected, the assembling tooling jig frame is erected on the hardened ground, and the assembling tooling jig frame upright posts are connected into a whole by adopting T-shaped steel and bridging to ensure the strength and stability of the assembling tooling jig frame.

4. The method for processing and manufacturing the curved variable-section steel box girder according to claim 2, wherein in the step 2, when the top plate unit is laid on the tooling reversing jig frame, the top plate unit needs to be corrected to be completely attached to the tooling reversing jig frame in a natural state, and the top plate unit is not forcibly attached to the tooling reversing jig frame in a spot welding and wedge code mode; in the process, the accurate measurement is needed to control the positioning accuracy of the pavement of the top plate units, the top plate units cannot deviate along the bridge direction, and when the deviation occurs, the positioning of the top plate units needs to be immediately adjusted, so that the longitudinal center line of each top plate unit is ensured to be parallel to the center line of the bridge.

5. The method for manufacturing and processing the curved variable cross-section steel box girder according to claim 2, wherein in the step 7, when the bottom plate unit is paved on the assembling tooling jig frame, the bottom plate unit is manufactured on the assembling tooling jig frame, automatic equipment is adopted for symmetrical welding during welding of bottom plate ribs to control welding deformation, the bottom plate unit is required to be completely attached to the assembling tooling jig frame after being welded and corrected to a natural state, and the bottom plate unit is forbidden to be forcibly attached to the assembling tooling jig frame in a spot welding and wedge code mode.

6. The method for processing and manufacturing the curved variable-section steel box girder according to claim 2, wherein the partition plate unit is manufactured on a platform, the web plate unit is manufactured on a web plate tool, the partition plate ribs of the partition plate unit and the web plate ribs of the web plate unit are symmetrically welded by automatic equipment during welding to control welding deformation, the partition plate ribs and the web plate ribs can be transferred to a next process after correction after each welding, and the partition plate unit and the web plate unit are checked by a plumb bob to ensure that the partition plate and the web plate are plumbed to the ground;

in the step 5, when the top plate unit, the partition plate unit and the web plate unit are welded into a whole, the partition plate unit and the web plate unit are firstly welded vertically, then the partition plate unit and the top plate unit are welded horizontally, and welding deformation is controlled by symmetrically welding; according to the different heights of web plate units of each section, a partition plate unit and the web plate unit are vertically welded in the length direction of a bottom plate unit for reserving 1-2 meters for non-welding, and after the assembly of the three-side box body and the bottom plate unit is completed on the assembling tooling jig frame, welding is carried out;

in the step 10, assembling a top plate shear key on the square box body to form a steel box beam; the steel box girder needs to be corrected and matched with a drill bolt hole, the connecting plate is accurately positioned by adopting a punching nail, and the box body is matched with a drill after being compressed by a common bolt.

7. The method for processing and manufacturing the curved variable-section steel box girder according to claim 1, wherein the method for processing the plate unit is carried out according to the following steps:

step (1), lofting, splicing and cutting are carried out on a processed material, and flaw detection of a welding seam is required in the process;

step (2), paying off the processed plate unit and polishing the welding edge of the part;

step (3) assembling spot welding plate ribs, wherein the welding seam flaw detection is required in the process;

step (4), welding the plate units, wherein the welding seam flaw detection is required in the process;

and (5) correcting the plate unit.

8. The method for processing and manufacturing the curved variable-section steel box girder according to the claim 7, wherein when the top plate unit is processed according to the plate unit processing method, a 12mm thick steel plate and a 22mm thick steel plate are adopted as materials for processing the top plate unit, a 22mm thick steel plate is adopted at a web plate line of a forward main girder and a transverse bridging transverse joint, and 12mm thick steel plates are adopted at the rest parts; the top plate unit comprises longitudinal and transverse links with the thickness of 22mm and a steel template with the thickness of 12mm, and web positioning lines are marked by the longitudinal and transverse links in blanking so as to ensure that the web units of adjacent steel box girder boxes are free from misalignment; during blanking, no groove is formed in the longitudinal and transverse connection, and a groove is formed in a 12mm steel template; the longitudinal and transverse connection and the steel template are respectively and independently blanked during blanking, then splicing is carried out, and two sides are spliced during splicing so as to ensure the flatness of the top plate and reduce the welding deformation caused by more welding lines of the top plate unit;

the web plate unit comprises a web plate and plate ribs, the cross section height of the web plate is 3m-6m, when the web plate unit is processed according to the plate processing unit method, the web plate unit is blanked according to the length divided by each tool, ocean punching holes of the partition plate units are punched inside and outside the web plate unit so as to assemble and position the partition plate units, the web plate unit is provided with an outer slope opening of 40 degrees, and no truncated edge is left; when the web plate of one tool position is machined into a whole section, cutting off a plurality of web plate sections after welding is finished, and drilling a single side of each web plate section in advance to reduce the air drilling amount; the assembly, welding and straightening of the web units are consistent with the top plate units.

9. The method for manufacturing a curved variable cross-section steel box girder according to claim 7, wherein the partition plate unit comprises a partition plate panel, longitudinal and transverse stiffening plate ribs and a manhole ring stiffening plate rib, when the partition plate unit is manufactured according to the method for manufacturing the partition plate unit, the partition plate panel is placed on a flat tooling surface and is welded by a robot according to the principle of first vertical joint and then horizontal joint and symmetrical welding from the middle to two sides so as to reduce welding deformation, when the plate thickness of the longitudinal and transverse stiffening plate ribs and the manhole ring stiffening plate rib is more than 16mm, a part of fusion welding seam with a groove is adopted, and when the plate thickness of the longitudinal and transverse stiffening plate ribs and the manhole ring stiffening plate rib is less than or equal to 16mm, a common fillet welding seam is adopted;

baffle stiffening plate ribs are arranged on two sides of the baffle panel, are positioned at the free contraction ends, and are subjected to warping deformation in different degrees at the periphery after welding, so that the flatness of the baffle panel needs to be corrected; when the baffle plate unit is corrected, a combined mode of flame correction and mechanical correction is adopted, and the middle local bubbling part of the baffle plate panel is corrected by adopting a uniformly distributed dot-shaped flame correction mode of 'quincunx dots';

when the bottom plate unit is processed according to the plate processing unit method, the bottom plate unit comprises a main beam bottom plate unit and a standard section bottom plate unit, web plate unit positioning lines need to be marked during blanking, the longitudinal stiffening ribs of the bottom plate unit with the arc shape adopt numerical control blanking, holes are drilled at two ends of the longitudinal stiffening ribs of the bottom plate unit, and a bottom plate unit connecting plate is subjected to scribing and matched drilling; the main beam bottom plate unit is welded on a reversible deformation welding jig frame and is welded by automatic lath rib welding equipment, and correction treatment is carried out after welding is finished;

leveling the main beam bottom plate unit on the tool platform which is subjected to the ultra-leveling treatment in a flame rectification mode, baking and stress relieving treatment is carried out on the back of the bottom plate unit at the position corresponding to the welding line of the plate rib, and flatness inspection is carried out on the leveled main beam bottom plate unit by adopting an aluminum alloy plate ruler with the length of 2 meters; and in the longitudinal direction, a bed jig is set up for checking and correcting after the bottom plate unit is welded.

10. The processing and manufacturing method of the curved variable cross-section steel box girder as claimed in claim 7, wherein the steel plate is leveled by a leveler and the surface of the steel plate is derusted and shop primer is sprayed by a pretreatment whole production line when the plate unit is processed, and the derusting grade reaches Sa2.5; the parts are cut by plasma numerical control, the lath is cut by a multi-head straight-bar cutting machine to ensure the blanking precision, and the hole is made by a numerical control plane drill;

the plate unit is assembled on an assembly jig frame, the edge and the end of a plate are used as positioning references, before assembly, a curve is connected point by point according to curve coordinates given by a sample drawing, transverse partition plate positioning center lines are drawn on a top plate, rib positioning line intervals of each strip plate are drawn on a top plate, rib positioning points are drawn on the transverse partition plates passing the points, web plate positioning side lines are drawn at the points between the two transverse partition plates, marks are drawn on the center lines of the transverse partition plates in a segmented mode by ocean punching, the paving and positioning accuracy of the top and bottom web plate units is controlled to ensure that the longitudinal center line of each bottom plate unit is parallel to the center line of a bridge, the flatness of the transverse partition plates after assembly and welding of a reinforcing ring is controlled, and the assembly size deviation of the plate rib plate units needs to be controlled within specifications;

when the plate unit is processed and welded, rust, oxide skin, oil stain and primer of a steel plate pretreatment workshop in a region to be welded are removed before assembly and welding are carried out, the cleaning range of two sides of a welding bead is not less than 30mm, the plate unit is required to be welded within 24h after assembly, welding is required to be carried out within 5h after a welding seam is polished under the working condition of high humidity in the region to be welded, the temperature of the welding environment is not lower than 0 ℃, the humidity is not less than 80%, welding starting is strictly prohibited in a non-welding region of a base metal during welding, slag and splashes are removed in time after welding, interlayer temperature is required to be continuously welded and controlled during multilayer welding, and a layer is welded after welding of each layer is finished; an arc striking plate and an arc extinguishing plate are required to be arranged at two ends of a butt joint welding seam, and the arc striking and extinguishing plates are removed by flame cutting and polished to be smooth after welding;

the plate unit needs to be corrected after being processed and welded, a combined mode of flame correction and mechanical correction is adopted, a mode of uniformly distributing point-shaped flame correction is adopted for local bubbling in the middle of the panel, the heating temperature is 600-800 ℃ during thermal correction, the temperature of parts needs to be slowly cooled after correction, and water quenching is avoided.

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