Construction method for preventing hoisting overturning of single arc-shaped steel box girder

Abstract

The invention provides a construction method for preventing hoisting overturning of a single arc-shaped steel box girder, and belongs to the technical field of hoisting of arc-shaped steel box girders. The method comprises the following steps: transporting the steel box girders and splicing the steel box girders on site; a crane is used for installing the steel box girder for construction; when the arc-shaped box girder is hoisted to a bridge pier, arc-shaped steel box girder overturning preventing devices are arranged on the side edges of the two ends of the arc-shaped box girder to prevent the arc-shaped box girder from overturning; and carrying out bridge position bolt connection and bridge position welding connection on the arc-shaped box beam to finish construction. The two cross beams are arranged at the two ends of the arc-shaped box girder, and the hoisting rope is tied to the end parts of the cross beams and the arc-shaped box girder during hoisting, so that the gravity center of the arc-shaped box girder can be controlled at the middle position of the arc bend of the arc-shaped box girder, the arc-shaped box girder is kept balanced during hoisting, and the overturning condition is avoided; meanwhile, the cross beam can also be used as a balance fixing device during installation, and if the width of a road is equal to that of a single-box arc-shaped box beam, the cross beam can be directly used as a long-term balance supporting device of the arc-shaped box beam.

Description

Technical Field

[0001] The invention relates to the field of arc-shaped steel box girder hoisting, and in particular to a construction method for preventing a single arc-shaped steel box girder from overturning during hoisting. Background Art

[0002] Steel box girders have good bending resistance, reliable torsion resistance and large spanning capacity, and have been widely used in urban bridge design with limited land use. However, their light weight is not conducive to the lateral anti-overturning of the structure. Especially during the hoisting process, overturning is prone to occur.

[0003] The Chinese patent with the announcement number CN213653170U discloses an anti-overturning structure suitable for small radius curved steel box girders, including a bridge pier body and a small radius curved steel box girder; two groups of double supports are fixed on both sides of the top surface of the bridge pier body; each group of the double supports is arranged on both sides of the axis of the bottom surface of the small radius curved steel box girder; the bridge pier body is pre-embedded with two rows of anti-overturning tie rods on both sides of the supports; the top of the anti-overturning tie rod passes through the bottom hole seat and pad of the small radius curved steel box girder; the pad is pressed against the top surface of the bottom hole seat; the anti-overturning tie rod is screwed with a clamping nut on the top surface of the pad. This device is used to fix the box girder in the later stage to prevent it from overturning, but during hoisting, because the center of the curved box girder is not on the connecting line of the two fulcrums, it is easy to overturn. Therefore, it is necessary to design a method to prevent the hoisting of a single curved steel box girder from overturning during the construction stage. Summary of the invention

[0004] The purpose of the present invention is to provide a construction method for preventing a single curved steel box girder from overturning during hoisting, so as to solve the technical problem that the existing single curved steel box girder is easy to overturn during hoisting.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A construction method for preventing a single curved steel box girder from overturning during hoisting, the method comprising the following steps:

[0007] Step 1: Transport the steel box girder and assemble the steel box girder on site;

[0008] Step 2: Use crane to install steel box girder construction;

[0009] Step 3: When the curved box girder is hoisted onto the bridge pier, an anti-overturning device for the curved steel box girder is installed on both ends of the curved box girder to prevent the curved box girder from overturning;

[0010] Step 4: Bolt and weld the curved box girder at the bridge position to complete the construction.

[0011] Furthermore, in step 3, the anti-overturning device of the curved steel box girder includes a crossbeam and a column. The crossbeam is arranged on the sides of both ends of the curved box girder, and the crossbeam is arranged on the outside of the curved bending direction of the curved box girder. During hoisting, the hoisting rope is tied to the end of the curved box girder and the crossbeam, the lower end of the column is connected to the top of the pier, and the crossbeam is connected to the top of the column.

[0012] Furthermore, the cross beam and the arc-shaped box beam are detachably arranged. When lifting is required, the cross beam is installed at both ends of the arc-shaped box beam. Box beam end side plates are arranged on the outer sides of the ends of the arc-shaped box beam. Box beam end side plate bolt holes are arranged on the box beam end side plates. The cross beam is connected and fixed to the box beam end side plates by bolts.

[0013] Furthermore, the column and the beam are fixed by bolts, bolt holes are arranged at both ends of the beam, and the bottom end of the column is embedded in the pier and arranged vertically.

[0014] Furthermore, the specific process of on-site assembly of the steel box girder in step 1 is as follows: adopting a structural form of pier support, first setting up piers in the site, and directly hoisting the steel box girder to the top of the pier for secondary assembly after the steel box girder transport vehicle arrives. The main structure of the pier is a φ219×10 steel pipe, and a 12×240×240 cover plate is set on the top. An adjusting tooth plate is placed on the cover plate to adjust the overall elevation. A 12×400×400 steel plate is set below as a base, and bolt holes are opened around it. Anchor bolts are used to firmly connect the pier to the ground. The height of the pier is 800mm;

[0015] When erecting the two-piece scaffold on site, first lay out the steel box girder ground sample line according to the scaffold drawing, and set up 6 piers under each production segment, and the piers are all located under the steel box girder partition.

[0016] Further, in step 2: crawler crane is used for lifting, after the steel box girder is assembled on the roadbed, the whole span is lifted into place, 4 lifting eyes are arranged, the maximum weight of the segment is 80t, and a safety factor of 1.2 is adopted. Considering that only 3 lifting eyes are subjected to force, the force on each lifting eye is F=80*1.2 / 3=33t, so 30-40t lifting eyes are selected, and the lifting weight of the segment is 60t or less, and the force on each lifting eye is F=60*1.2 / 3=24t, so 20-30t lifting eyes are used;

[0017] The principle of lifting lug arrangement is as follows: the lifting lugs are arranged at the corresponding positions on the upper part of the partition and the web, the lifting lugs are welded to the top plate, and the relative positions of four or two lifting points are placed according to the center of gravity to ensure that the four or two lifting points of the beam section are balanced in force. According to the crane model, wire rope length, beam section length, crane arm length and other working conditions, ensure that the angle between the wire rope and the steel beam section is greater than 60.

[0018] Furthermore, the process of on-site assembly of the crawler crane in step 2 is: unloading and installation of the main machine → installation of crawler tracks → installation of tail counterweight → assembly of main boom → insertion of hook → lifting → setting and inspection of working conditions → no-load test;

[0019] Crawler crane installation:

[0020] (1) Unloading and installation of the main engine: Make sure the work site is flat and solid. Four steel plates are required, with the dimensions of 9 meters long, 2.2 meters wide, and 30 mm thick. The distance between two steel plates is 2.8 meters. The trailer carries the main engine to the assembly site, adjusts the trailer position, starts the crawler crane engine, and sets it to assembly operation mode;

[0021] Pull out the outrigger positioning pin, rotate the outrigger to the working position, insert the positioning pin, place the frame outrigger disc under the outrigger oil cylinder, operate the frame outrigger oil cylinder, slowly press the outrigger oil cylinder on the outrigger disc, pay attention to prevent the outrigger disc from falling, lift the main body of the whole machine, lift the main engine component cylinder, lift it to 1.15 meters, keep it still for 3 minutes, observe safety, and then slowly drive out the trailer, and the main body is unloaded from the flatbed truck by itself and separated from the flatbed truck;

[0022] (2) Install the track:

[0023] Start the engine and put the main engine in standby mode.

[0024] Use a ton crawler crane to lift the crawler and slowly move it close to the frame, insert the single ear on the crawler into the double ears on the frame, slowly operate the vertical cylinder of the frame to align the pin holes on the crawler frame and the frame, operate the handle on the side of the frame to fully insert the pin, fix the pin with a baffle, install the other crawler in the same way, connect the quick connector, retract the vertical cylinder, and reverse the disassembly process, assemble the left and right walking plates, adjust the cab, rotate 900, pull the A-type operating handle, and pop up the A-type frame. After checking that everything is correct, slowly lift the A-type frame to 1200 and rotate the vehicle body 900;

[0025] (3) Install the tail counterweight: The crawler crane mast automatically unloads the counterweight block, and the luffing mast lifts the counterweight tray to the appropriate position to complete the installation of the counterweight block. The counterweight block and the counterweight tray are connected with a chain, and the screws on the adjustment plate are tightened to press and lock the counterweight block;

[0026] (4) Assemble the main boom: Use 4 lifting belts to hoist the crawler crane main boom through the auxiliary crane, corresponding to the connection holes on the main boom rod, and then use the pinning machine to drive the connecting pin shaft into the main boom rod and insert the buckle. The installation order is the main boom rod root, 6m arm, 12m arm, 12m arm, 12m arm, 12m arm, main boom rod head. The total installation length of this main boom is 60 meters. Connect the hydraulic oil pipe of the main boom rod seat, remove the tie rod pins of the pulley block and the main boom rod seat, connect the tie rods on the pulley block and the main boom rod, remove the front tie rod locking pin shaft on the main boom rod, and connect the main boom rod cable plug at the same time. Check whether the tie rod connection is correct. After confirmation, operate the 1# winch, pull up the main boom rod, install the main boom buffer rod and buffer rod bracket, select the hook and ratio, thread the lifting wire rope, connect the electrical cable at the same time, install the height limit device and the arm end pulley, and operate the amplitude change handle to make the boom stand upright;

[0027] (5) Threading the hook: Use an auxiliary crane to lift the 130t hook and place it at the designated location. Install the instructions and working conditions, reverse the traction wire rope, connect the traction wire rope with the 1# winch wire rope, operate the traction wire rope winch and the 1# winch, retract the traction wire rope while releasing the 1# winch wire rope, let the 1# winch wire rope pass through the L-bar head pulley and the hook pulley, install the wire rope anti-slip pin shaft, install the wire rope lock, install the limit device, and continue to lift the boom;

[0028] (6) Lifting, organization is completed, and all assembly tools are checked to see if they are left on the boom. Check whether the length and model of the connecting pull plates between the components are correct, and check whether the safety pins of the mounting pins are complete. After checking that all components and safety pins are installed, the crane driver is instructed to slowly lift the crane boom. During the lifting process, the hook should always be on the ground. The hook can only be lifted off the ground after the main boom angle reaches more than 60°. After the inspection is qualified, the lifting operation should be carried out slowly according to the instructions. The crane working conditions are set in the computer according to the organized crane working conditions. The equipment of the crane is checked during the empty crane operation to confirm that all working parts are in good condition and operating normally.

[0029] (7) No-load test: A no-load test can be carried out only after the technical inspection is passed, in order to check the correctness of the control action of the electrical equipment, the accuracy of the action of each mechanism, and to adjust each safety limit indicator device. The test content is as follows: the lifting mechanism is lifted at rated speed throughout the entire range at various amplitude positions, the empty hook is lowered three times each, the variable amplitude mechanism is within the full amplitude range, the boom is raised and lowered three times each, the slewing mechanism is in the maximum amplitude state, and the boom is rotated 360° to the left and right three times each, and the walking mechanism is within the walking range, and moves forward and backward once each time, but each continuous walking time should not exceed ten minutes.

[0030] Furthermore, in step 3, before hoisting, the cross beams at both ends of the curved box beam are connected to the curved box beam as a whole with bolts, and φ219×8 columns are placed under the cross beams on the concrete cap beam in advance, so that after the curved box beam is hoisted into place, the center of gravity of the curved box beam is within the line connecting the on-site support and the pier, so that it can play an anti-overturning role. The columns are fixed to the cap beam by means of flanges and anchor bolts. After the curved box beam is in place, the cross beams are welded to the columns.

[0031] Furthermore, in step 4, the specific process of bolt connection of the steel box girder bridge position is as follows: the bolt connection of the bridge position includes bolt connection between steel box girder segments and bolt connection between the cross beam and the steel box girder, and the installation process of the high-strength bolts is as follows:

[0032] 1) After the steel beam is hoisted in place, when assembling it by the bracket method, each joint should be driven with 25% of the nails as required. When assembling the cantilever beam, each joint should be driven with 50% of the nails as required, and arranged alternately with the bolt holes. Then check whether all the bolt holes can ensure the smooth and free passage of the high bolts. If not, report to the chief engineer and the on-site supervisor, and then study and deal with it according to the specific situation. Use no less than four ordinary bolts to clamp the gap between the steel beam node connection plate surfaces. Only after they are tightly fitted can high-strength bolts be installed. If the plate surface cannot be tightly fitted, high-strength bolts cannot be installed. Report to the chief engineer and the on-site supervisor, and then study and deal with it according to the specific situation. High-strength bolts shall not be used as temporary installation bolts during the installation process.

[0033] 2) Before installing high-strength bolts, the appearance of the bolts should be inspected. High-strength bolts with rust, damaged threads, damp surfaces, dust, sand, or changes in surface conditions should not be used. High-strength bolts with changed surface conditions should be sent back to the original manufacturer for re-surface treatment. After re-treatment, they should be re-inspected according to the original supply requirements and can only be used after passing the inspection;

[0034] 3) When installing high-strength bolts, there is a washer on each side of the bolt head and the nut. The chamfered side of the washer faces the bolt head and the nut support surface respectively; the marked side of the nut faces outwards;

[0035] 4) In order to facilitate construction and improve the appearance of the entire bridge, the installation direction of high-strength bolts is specified as follows:

[0036] (a) The nuts of the high-strength bolts on all main beam facades of the bridge shall be installed on the outside of the gusset plate;

[0037] (b) When the nut position of high-strength bolts in individual parts cannot meet the above requirements, the project chief engineer may be consulted to determine the direction of the bolts. The direction of insertion should be based on the principles of ease of tightening, good appearance and consistency of the entire bridge;

[0038] 5) When installing high-strength bolts, the bolts should be inserted into the holes smoothly and should not be forced in. A certain number of positioning pins should be punched first to ensure that the gaps overlap before installing the bolts. If the bolts cannot be inserted freely, the hole should be trimmed with a reamer. The maximum diameter of the hole after trimming should be less than 1.2 times the bolt diameter. When repairing the hole, in order to prevent iron filings from falling into the gap between the plates, all the bolts around should be tightened before reaming the hole, so that the plates are closely attached before repairing. It is strictly forbidden to use gas cutting to expand the hole. If the bolts cannot be inserted freely after the hole is reamed to 1.2 times the bolt diameter, the splicing plate should be re-matched;

[0039] 6) The axis of the installed high-strength bolts should be perpendicular to the surface of the node plate. Otherwise, find out the reason and reinstall;

[0040] Tightening of high-strength bolts:

[0041] 1) The high-strength bolts of this bridge are tightened by the torque method and controlled by the torque method. That is, based on a series of process tests, the tightening of high-strength bolts is divided into two stages: initial tightening and final tightening.

[0042] High-strength bolt installation steps:

[0043] (a) Install high-strength bolts corresponding to the bolt holes that have neither punches nor ordinary bolts installed. The installation sequence is from the center of the node to the surrounding area, and tighten them with a plum wrench;

[0044] (b) Replace ordinary bolts with high-strength bolts one by one, starting from the center of the node and moving toward the surrounding areas, and tighten them simultaneously with a plum wrench;

[0045] (c) Use a calibrated initial tightening wrench to initially tighten the high-strength bolts that have been tightened with a box spanner, 50% of the final tightening torque, and make initial tightening marks. The tightening sequence should spread from the center of the node to the surrounding areas;

[0046] (d) Remove the punches in batches, replace them with high-strength bolts, and perform initial tightening, 50% of the final tightening torque, and use a blue paint pen to mark the initial tightening;

[0047] (e) All high-strength bolts that have been initially tightened shall be tightened to a final torque of 100%. The tightening sequence shall be from the center of the node to the surrounding areas. At the same time, the final tightening mark shall be made with red paint. The initial tightening and final tightening shall be completed on the same working day.

[0048] (f) Within 24 hours after the final tightening, the bolts tightened on that day shall be checked according to the specified quantity using a dial wrench and marked with yellow paint;

[0049] 3) Initial tightening: After the high-strength bolts are installed into the bolt holes and checked to be correct, tighten them with an ordinary plum-shaped manual wrench first, and then use a calibrated electric wrench to tighten the bolts to 50% of the final tightening torque to complete the initial tightening;

[0050] 4) For high-strength bolts that have been initially tightened, a straight line should be immediately drawn on the nut, washer and plate surface with a blue marker to prevent repeated tightening, omissions and facilitate inspection;

[0051] 5) Final tightening: The final tightening torque value of each batch of high-strength bolts is determined by the following formula:

[0052] TC=K×PC×d

[0053] In the formula: TC is the final tightening torque value of the high-strength bolt, PC is the construction pre-tension value of the high-strength bolt, K is the average value of the torque coefficient of each batch of high-strength bolts, d is the nominal diameter of the high-strength bolt, and the average value K of the torque coefficient of the high-strength bolt in the formula is determined by the test;

[0054] 6) Final tightening is completed by a calibrated electric torque wrench. For bolts in some parts where electric tools cannot be used, a calibrated dial inspection wrench or a manual wrench with a sound is used to complete the final tightening;

[0055] 7) During the tightening process of high-strength bolts, the bolt head and washer shall not rotate with the nut. If the bolt or washer is found to rotate, the high-strength bolt shall be replaced and the initial tightening and final tightening operations shall be repeated. The replaced high-strength bolts shall be returned to the warehouse and sent back to the factory for centralized processing. They can only be used after passing the acceptance inspection. It is strictly forbidden to use them directly again;

[0056] 8) When tightening high-strength bolts, the use of manual torque wrenches must be uniform, and impact force must not be used. When the electric torque wrench is started, it must be operated continuously and smoothly until the electric wrench stops automatically. After the electric wrench stops automatically, it is strictly forbidden to start the electric wrench again to tighten the bolt to prevent over-tightening;

[0057] 9) Whether in the initial tightening or final tightening stage, or when using different wrenches, the tightening sequence should generally be from the center of the bolt group to the surrounding area. If this cannot be followed for special parts, report to the chief engineer for further processing;

[0058] 10) During construction, the electric wrench should use an independent power supply or a voltage-stabilized power supply to reduce voltage fluctuations that affect the output stability of the electric wrench torque;

[0059] 11) If any abnormality or failure occurs during the use of various wrenches, on-site construction personnel shall not handle them without authorization, and must immediately stop construction, hand over the wrench to the high-strength bolt test team for inspection and repair, and report the failure so that corresponding measures can be formulated to deal with the on-site bolts;

[0060] High-strength bolt construction quality inspection:

[0061] (1) According to the relevant regulations on the construction quality inspection of high-strength bolts, the construction quality inspection of high-strength bolts should be carried out by specialized test and inspection personnel, with the cooperation of construction personnel, and completed within 4-24 hours after the final tightening of the high-strength bolts;

[0062] For the initial tightening check, use a 0.3kg hammer to hit each nut one by one, and press the opposite side of the nut with your finger. If you feel that the nut vibrates too much or is loose, it means that the bolt is under-tightened or missed, and needs to be re-tightened. Alternatively, use the marking method to confirm the initial tightening, that is, use blue, red, and white paint to mark the different states of the bolt for the initial tightening, final tightening, and inspection respectively;

[0063] (2) Final tightening inspection of high-strength bolts: Final tightening inspection shall be carried out with a calibrated torque inspection wrench, and its accuracy error shall be less than 3% of the torque value of the wrench;

[0064] 1) Before checking with a torque check wrench, visually check the misalignment of the markings when the initial tightening is completed to determine whether there is any missing tightening during the final tightening and whether the gasket or bolt has rotated. If the markings are not misaligned, it means that the bolt is missing. If the misalignment is too large, the bolt may be over-tightened or the gasket may slip, which should be checked;

[0065] 2) The final tightening torque inspection is carried out by the tightening method, that is, the nut is tightened along the tightening direction with a pointer dial inspection wrench for the final tightened high-strength bolt. The inspector evenly applies force to the wrench handle to increase the torque indication at a uniform speed and the pointer rotates smoothly. When the pointer pauses, it means that the torque value has caused the nut to rotate slightly, and this torque value is the final tightening inspection torque value of the bolt;

[0066] 3) Before the tightening inspection, draw a thin line on the nut and washer to monitor the rotation of the nut. To prevent the bolt head from rotating with the nut during the inspection, which may cause misjudgment, the inspector should pay attention and bring a locking tool;

[0067] 4) The on-site inspection torque value should be within 0.9~1.1Tch, where the tightening inspection torque Tch is the inspection torque of the high-strength bolt, which is determined by the test. If it exceeds the limit, the final tightening inspection torque value of the bolt is unqualified;

[0068] 5) The number of high-strength bolts to be inspected at each node shall be 5% of the total number of bolt groups at the corresponding node, but shall not be less than two sets;

[0069] 6) For unqualified nodes, the number of unqualified nodes shall not exceed 20% of the total number of spot checks, otherwise spot checks shall be continued until 80% of the cumulative bolt group is reached, and then the under-tightened bolts shall be tightened, and the over-tightened bolts shall be replaced and re-tightened;

[0070] 7) The high-strength bolts that are inserted into the node plate on site must be initially tightened and finally tightened on the same day. The high-strength bolts after final tightening must be inspected and marked on the same day. For those that fail to meet the standards, timely handling opinions must be given, and records and visas must be kept.

[0071] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0072] (1) The present invention provides two cross beams at both ends of the arc box beam. When hoisting, the hoisting rope is tied to the ends of the cross beam and the arc box beam, so that the center of gravity of the arc box beam can be controlled at the middle position of the arc bend of the arc box beam, so that the arc box beam can be balanced when hoisting and will not overturn. At the same time, the cross beam can also be used as a balancing fixing device during installation. If the road is the width of a single arc box beam, the cross beam can be directly used as a long-term balancing support device for the arc box beam;

[0073] (2) By arranging the hanging points of the beams at both ends during hoisting, the lateral force width of the hoisting is increased, and the center position of the curved box girder is changed, making hoisting more convenient without tipping on one side. Moreover, it is fixed with external bolts and can be designed according to the force requirements, making later maintenance more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 It is a flow chart of the hoisting process of the present invention;

[0075] Figure 2 It is a schematic diagram of the end structure of the curved steel box girder of the present invention;

[0076] Figure 3 It is a schematic diagram of the force analysis structure of the curved steel box girder of the present invention.

[0077] In the attached drawings, 1-bridge pier, 2-support flange, 3-arc box girder, 4-side plate at the end of the box girder, 5-bolt hole at the side plate at the end of the box girder, 6-crossbeam, 7-bolt hole at the first end of the crossbeam, 8-bolt hole at the second end of the crossbeam, 9-column, 10-support flange connecting line, 11-hoisting support connecting line area, 12-center of gravity position of the arc box girder. DETAILED DESCRIPTION

[0078] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and preferred embodiments. However, it should be noted that many details listed in the specification are only for the purpose of enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0079] like Figure 1As shown, a construction method for preventing a single curved steel box girder from overturning during hoisting, the method comprising the following steps:

[0080] Step 1: Transport and assemble the steel box beam on site. The pier-supported structure is adopted. The piers are set up on site first. After the steel box beam transporter arrives, the steel box beam is directly hoisted to the top of the pier for secondary assembly. The main structure of the pier is φ219×10 steel pipe, with a 12×240×240 cover plate on the top. The adjustment tooth plate is placed on the cover plate to adjust the overall elevation. A 12×400×400 steel plate is set as the base below. Bolt holes are opened around the pier. Anchor bolts are used to firmly connect the pier to the ground. The height of the pier is 800mm.

[0081] When erecting the two-piece scaffold on site, first lay out the steel box girder ground sample line according to the scaffold drawing, and set up 6 piers under each production segment, and the piers are all located under the steel box girder partition.

[0082] Step 2: Use a crane to install the steel box girder. Use a crawler crane to lift the steel box girder. After the steel box girder is assembled on the roadbed, the entire span is hoisted into place. Arrange 4 lifting lugs. The maximum weight of the segment is 80t. Use a 1.2 times safety factor. Considering that only 3 lifting lugs are stressed, the force on each lifting lug is F=80*1.2 / 3=33t. Therefore, a 30-40t lifting lug is selected. For segments with a lifting weight of 60t or less, the force on each lifting lug is F=60*1.2 / 3=24t. Therefore, a 20-30t lifting lug is used.

[0083] The principle of lifting lug arrangement is as follows: the lifting lugs are arranged at the corresponding positions on the upper part of the partition and the web, the lifting lugs are welded to the top plate, and the relative positions of four or two lifting points are placed according to the center of gravity to ensure that the four or two lifting points of the beam section are balanced in force. According to the crane model, wire rope length, beam section length, crane arm length and other working conditions, ensure that the angle between the wire rope and the steel beam section is greater than 60.

[0084] The process of crawler crane on-site assembly is: unloading and installation of the main engine → installation of crawler tracks → installation of tail counterweight → assembly of main boom → insertion of hooks → lifting → setting and inspection of working conditions → no-load test;

[0085] Crawler crane installation:

[0086] (1) Unloading and installation of the main engine: Make sure the work site is flat and solid. Four steel plates are required, with the dimensions of 9 meters long, 2.2 meters wide, and 30 mm thick. The distance between two steel plates is 2.8 meters. The trailer carries the main engine to the assembly site, adjusts the trailer position, starts the crawler crane engine, and sets it to assembly operation mode;

[0087] Pull out the outrigger positioning pin, rotate the outrigger to the working position, insert the positioning pin, place the frame outrigger disc under the outrigger oil cylinder, operate the frame outrigger oil cylinder, slowly press the outrigger oil cylinder on the outrigger disc, pay attention to prevent the outrigger disc from falling, lift the main body of the whole machine, lift the main engine component cylinder, lift it to 1.15 meters, keep it still for 3 minutes, observe safety, and then slowly drive out the trailer, and the main body is unloaded from the flatbed truck by itself and separated from the flatbed truck;

[0088] (2) Install the track:

[0089] Start the engine and put the main engine in standby mode.

[0090] Use a ton crawler crane to lift the crawler and slowly move it close to the frame, insert the single ear on the crawler into the double ears on the frame, slowly operate the vertical cylinder of the frame to align the pin holes on the crawler frame and the frame, operate the handle on the side of the frame to fully insert the pin, fix the pin with a baffle, install the other crawler in the same way, connect the quick connector, retract the vertical cylinder, and reverse the disassembly process, assemble the left and right walking plates, adjust the cab, rotate 900, pull the A-type operating handle, and pop up the A-type frame. After checking that everything is correct, slowly lift the A-type frame to 1200 and rotate the vehicle body 900;

[0091] (3) Install the tail counterweight: The crawler crane mast automatically unloads the counterweight block, and the luffing mast lifts the counterweight tray to the appropriate position to complete the installation of the counterweight block. The counterweight block and the counterweight tray are connected with a chain, and the screws on the adjustment plate are tightened to press and lock the counterweight block;

[0092] (4) Assemble the main boom: Use 4 lifting belts to hoist the crawler crane main boom through the auxiliary crane, corresponding to the connection holes on the main boom rod, and then use the pinning machine to drive the connecting pin shaft into the main boom rod and insert the buckle. The installation order is the main boom rod root, 6m arm, 12m arm, 12m arm, 12m arm, 12m arm, main boom rod head. The total installation length of this main boom is 60 meters. Connect the hydraulic oil pipe of the main boom rod seat, remove the tie rod pins of the pulley block and the main boom rod seat, connect the tie rods on the pulley block and the main boom rod, remove the front tie rod locking pin shaft on the main boom rod, and connect the main boom rod cable plug at the same time. Check whether the tie rod connection is correct. After confirmation, operate the 1# winch, pull up the main boom rod, install the main boom buffer rod and buffer rod bracket, select the hook and ratio, thread the lifting wire rope, connect the electrical cable at the same time, install the height limit device and the arm end pulley, and operate the amplitude change handle to make the boom stand upright;

[0093] (5) Threading the hook: Use an auxiliary crane to lift the 130t hook and place it at the designated location. Install the instructions and working conditions, reverse the traction wire rope, connect the traction wire rope with the 1# winch wire rope, operate the traction wire rope winch and the 1# winch, retract the traction wire rope while releasing the 1# winch wire rope, let the 1# winch wire rope pass through the L-bar head pulley and the hook pulley, install the wire rope anti-slip pin shaft, install the wire rope lock, install the limit device, and continue to lift the boom;

[0094] (6) Lifting, organization is completed, and all assembly tools are checked to see if they are left on the boom. Check whether the length and model of the connecting pull plates between the components are correct, and check whether the safety pins of the mounting pins are complete. After checking that all components and safety pins are installed, the crane driver is instructed to slowly lift the crane boom. During the lifting process, the hook should always be on the ground. The hook can only be lifted off the ground after the main boom angle reaches more than 60°. After the inspection is qualified, the lifting operation should be carried out slowly according to the instructions. The crane working conditions are set in the computer according to the organized crane working conditions. The equipment of the crane is checked during the empty crane operation to confirm that all working parts are in good condition and operating normally.

[0095] (7) No-load test: A no-load test can be carried out only after the technical inspection is passed, in order to check the correctness of the control action of the electrical equipment, the accuracy of the action of each mechanism, and to adjust each safety limit indicator device. The test content is as follows: the lifting mechanism is lifted at rated speed throughout the entire range at various amplitude positions, the empty hook is lowered three times each, the variable amplitude mechanism is within the full amplitude range, the boom is raised and lowered three times each, the slewing mechanism is in the maximum amplitude state, and the boom is rotated 360° to the left and right three times each, and the walking mechanism is within the walking range, and moves forward and backward once each time, but each continuous walking time should not exceed ten minutes.

[0096] Step 3: If Figure 2-3 As shown, when the curved box girder 3 is hoisted onto the pier 1, a curved steel box girder anti-overturning device is arranged on the sides of both ends of the curved box girder 3 to prevent the curved box girder 3 from overturning. The curved steel box girder anti-overturning device includes a cross beam 6 and a column 9. The cross beam 6 is arranged on the sides of both ends of the curved box girder 3. The cross beam 6 is arranged on the outside of the curved bending direction of the curved box girder 3. During hoisting, the hoisting rope is tied to the ends of the curved box girder 3 and the cross beam 6. The lower end of the column 9 is connected to the top of the pier 1, and the cross beam 6 is connected to the top of the column 9. The cross beam 6 and the curved box girder 3 are detachably arranged. When hoisting is required, the cross beam 6 is installed on both ends of the curved box girder 3. The outer side of the ends of the curved box girder 3 is provided with a box girder end side plate 4. The box girder end side plate 4 is provided with a box girder end side plate bolt hole 5. The cross beam 6 is connected and fixed to the box girder end side plate 4 by bolts.

[0097] During hoisting, the hoisting rope is tied to the end of the curved box beam 3 and the cross beam 6. Figure 3As shown, during hoisting, the length of the cross beam 6 is set according to the center of gravity position 12 of the curved box beam, so as to achieve better control of the center of gravity position 12 of the curved box beam. Figure 2 As shown, during installation, the connection line of the two support flanges 2 (support flange connection line 10) and the center of gravity position 12 of the curved box beam are not in a straight line, and the deviation is relatively large. If it is not fixed during installation, the curved box beam 3 is likely to tip over. However, with the fixation of the cross beam 6, the center of force coincides with the center of gravity position 12 of the curved box beam, maintaining balance, as shown in FIG. Figure 2 The lifting support connection line area 11 is shown.

[0098] The cross beam 6 and the arc box beam 3 are detachable. When hoisting is required, the cross beam 6 is installed at both ends of the arc box beam 3. The cross beam 6 is set as a detachable structure mainly so that when installing multiple arc box beams 3, two arc box beams 3 can be connected together to adjust the center of gravity, and balance can be achieved, and the cross beam 6 can be removed in time. The end of the arc box beam 3 is provided with a box beam end side plate 4 on the outer side, and the box beam end side plate bolt hole 5 is provided on the box beam end side plate 4. The cross beam 6 is connected and fixed to the box beam end side plate 4 by bolts. The box beam end side plate 4 is fixed according to the size at the factory, and the bolt hole is opened according to the set drawing. The lower end of the column 9 is connected to the top of the pier 1, and the cross beam 6 is connected to the top of the column 9. The column 9 is fixed to the cross beam 6 by bolts, and bolt holes are provided at both ends of the cross beam 6. The bottom end of the column 9 is pre-buried in the pier 1 and is vertically arranged.

[0099] There are two cross beams at both ends. When hoisting, the hoisting ropes are tied to the cross beams and the ends of the curved box beams, so that the center of gravity of the curved box beam can be controlled in the middle position of the arc of the curved box beam, so that the curved box beam can be balanced during hoisting and will not overturn. At the same time, the cross beams can also be used as a balancing fixing device during installation. If the road is the width of a single-box curved box beam, the cross beam can be directly used as a long-term balancing support device for the curved box beam, achieving multiple effects at one stroke.

[0100] Step 4: Complete the construction by bolting and welding the curved box girder 3 bridge positions. The specific process of bolting the steel box girder bridge position is as follows: The bridge position bolting includes bolting between steel box girder segments and bolting between the crossbeam and the steel box girder. The installation process of high-strength bolts is as follows:

[0101] 1) After the steel beam is hoisted in place, when assembling it by the bracket method, each joint should be driven with 25% of the nails as required. When assembling the cantilever beam, each joint should be driven with 50% of the nails as required, and arranged alternately with the bolt holes. Then check whether all the bolt holes can ensure the smooth and free passage of the high bolts. If not, report to the chief engineer and the on-site supervisor, and then study and deal with it according to the specific situation. Use no less than four ordinary bolts to clamp the gap between the steel beam node connection plate surfaces. Only after they are tightly fitted can high-strength bolts be installed. If the plate surface cannot be tightly fitted, high-strength bolts cannot be installed. Report to the chief engineer and the on-site supervisor, and then study and deal with it according to the specific situation. High-strength bolts shall not be used as temporary installation bolts during the installation process.

[0102] 2) Before installing high-strength bolts, the appearance of the bolts should be inspected. High-strength bolts with rust, damaged threads, damp surfaces, dust, sand, or changes in surface conditions should not be used. High-strength bolts with changed surface conditions should be sent back to the original manufacturer for re-surface treatment. After re-treatment, they should be re-inspected according to the original supply requirements and can only be used after passing the inspection;

[0103] 3) When installing high-strength bolts, there is a washer on each side of the bolt head and the nut. The chamfered side of the washer faces the bolt head and the nut support surface respectively; the marked side of the nut faces outwards;

[0104] 4) In order to facilitate construction and improve the appearance of the entire bridge, the installation direction of high-strength bolts is specified as follows:

[0105] (a) The nuts of the high-strength bolts on all main beam facades of the bridge shall be installed on the outside of the gusset plate;

[0106] (b) When the nut position of high-strength bolts in individual parts cannot meet the above requirements, the project chief engineer may be consulted to determine the direction of the bolts. The direction of insertion should be based on the principles of ease of tightening, good appearance and consistency of the entire bridge;

[0107] 5) When installing high-strength bolts, the bolts should be inserted into the holes smoothly and should not be forced in. A certain number of positioning pins should be punched first to ensure that the gaps overlap before installing the bolts. If the bolts cannot be inserted freely, the hole should be trimmed with a reamer. The maximum diameter of the hole after trimming should be less than 1.2 times the bolt diameter. When repairing the hole, in order to prevent iron filings from falling into the gap between the plates, all the bolts around should be tightened before reaming the hole, so that the plates are closely attached before repairing. It is strictly forbidden to use gas cutting to expand the hole. If the bolts cannot be inserted freely after the hole is reamed to 1.2 times the bolt diameter, the splicing plate should be re-matched;

[0108] 6) The axis of the installed high-strength bolts should be perpendicular to the surface of the node plate. Otherwise, find out the reason and reinstall;

[0109] Tightening of high-strength bolts:

[0110] 1) The high-strength bolts of this bridge are tightened by the torque method and controlled by the torque method. That is, based on a series of process tests, the tightening of high-strength bolts is divided into two stages: initial tightening and final tightening.

[0111] High-strength bolt installation steps:

[0112] (a) Install high-strength bolts corresponding to the bolt holes that have neither punches nor ordinary bolts installed. The installation sequence is from the center of the node to the surrounding area, and tighten them with a plum wrench;

[0113] (b) Replace ordinary bolts with high-strength bolts one by one, starting from the center of the node and moving toward the surrounding areas, and tighten them simultaneously with a plum wrench;

[0114] (c) Use a calibrated initial tightening wrench to initially tighten the high-strength bolts that have been tightened with a box spanner, 50% of the final tightening torque, and make initial tightening marks. The tightening sequence should spread from the center of the node to the surrounding areas;

[0115] (d) Remove the punches in batches, replace them with high-strength bolts, and perform initial tightening, 50% of the final tightening torque, and use a blue paint pen to mark the initial tightening;

[0116] (e) All high-strength bolts that have been initially tightened shall be tightened to a final torque of 100%. The tightening sequence shall be from the center of the node to the surrounding areas. At the same time, the final tightening mark shall be made with red paint. The initial tightening and final tightening shall be completed on the same working day.

[0117] (f) Within 24 hours after the final tightening, the bolts tightened on that day shall be checked according to the specified quantity using a dial wrench and marked with yellow paint;

[0118] 3) Initial tightening: After the high-strength bolts are installed into the bolt holes and checked to be correct, tighten them with an ordinary plum-shaped manual wrench first, and then use a calibrated electric wrench to tighten the bolts to 50% of the final tightening torque to complete the initial tightening;

[0119] 4) For high-strength bolts that have been initially tightened, a straight line should be immediately drawn on the nut, washer and plate surface with a blue marker to prevent repeated tightening, omissions and facilitate inspection;

[0120] 5) Final tightening: The final tightening torque value of each batch of high-strength bolts is determined by the following formula:

[0121] TC=K×PC×d

[0122] In the formula: TC is the final tightening torque value of the high-strength bolt, PC is the construction pre-tension value of the high-strength bolt, K is the average value of the torque coefficient of each batch of high-strength bolts, d is the nominal diameter of the high-strength bolt, and the average value K of the torque coefficient of the high-strength bolt in the formula is determined by the test;

[0123] 6) Final tightening is completed by a calibrated electric torque wrench. For bolts in some parts where electric tools cannot be used, a calibrated dial inspection wrench or a manual wrench with a sound is used to complete the final tightening;

[0124] 7) During the tightening process of high-strength bolts, the bolt head and washer shall not rotate with the nut. If the bolt or washer is found to rotate, the high-strength bolt shall be replaced and the initial tightening and final tightening operations shall be repeated. The replaced high-strength bolts shall be returned to the warehouse and sent back to the factory for centralized processing. They can only be used after passing the acceptance inspection. It is strictly forbidden to use them directly again;

[0125] 8) When tightening high-strength bolts, the use of manual torque wrenches must be uniform, and impact force must not be used. When the electric torque wrench is started, it must be operated continuously and smoothly until the electric wrench stops automatically. After the electric wrench stops automatically, it is strictly forbidden to start the electric wrench again to tighten the bolt to prevent over-tightening;

[0126] 9) Whether in the initial tightening or final tightening stage, or when using different wrenches, the tightening sequence should generally be from the center of the bolt group to the surrounding area. If this cannot be followed for special parts, report to the chief engineer for further processing;

[0127] 10) During construction, the electric wrench should use an independent power supply or a voltage-stabilized power supply to reduce voltage fluctuations that affect the output stability of the electric wrench torque;

[0128] 11) If any abnormality or failure occurs during the use of various wrenches, on-site construction personnel shall not handle them without authorization, and must immediately stop construction, hand over the wrench to the high-strength bolt test team for inspection and repair, and report the failure so that corresponding measures can be formulated to deal with the on-site bolts;

[0129] High-strength bolt construction quality inspection:

[0130] (1) According to the relevant regulations on the construction quality inspection of high-strength bolts, the construction quality inspection of high-strength bolts should be carried out by specialized test and inspection personnel, with the cooperation of construction personnel, and completed within 4-24 hours after the final tightening of the high-strength bolts;

[0131] For the initial tightening check, use a 0.3kg hammer to hit each nut one by one, and press the opposite side of the nut with your finger. If you feel that the nut vibrates too much or is loose, it means that the bolt is under-tightened or missed, and needs to be re-tightened. Alternatively, use the marking method to confirm the initial tightening, that is, use blue, red, and white paint to mark the different states of the bolt for the initial tightening, final tightening, and inspection respectively;

[0132] (2) Final tightening inspection of high-strength bolts: Final tightening inspection shall be carried out with a calibrated torque inspection wrench, and its accuracy error shall be less than 3% of the torque value of the wrench;

[0133] 1) Before checking with a torque check wrench, visually check the misalignment of the markings when the initial tightening is completed to determine whether there is any missing tightening during the final tightening and whether the gasket or bolt has rotated. If the markings are not misaligned, it means that the bolt is missing. If the misalignment is too large, the bolt may be over-tightened or the gasket may slip, which should be checked;

[0134] 2) The final tightening torque inspection is carried out by the tightening method, that is, the nut is tightened along the tightening direction with a pointer dial inspection wrench for the final tightened high-strength bolt. The inspector evenly applies force to the wrench handle to increase the torque indication at a uniform speed and the pointer rotates smoothly. When the pointer pauses, it means that the torque value has caused the nut to rotate slightly, and this torque value is the final tightening inspection torque value of the bolt;

[0135] 3) Before the tightening inspection, draw a thin line on the nut and washer to monitor the rotation of the nut. To prevent the bolt head from rotating with the nut during the inspection, which may cause misjudgment, the inspector should pay attention and bring a locking tool;

[0136] 4) The on-site inspection torque value should be within 0.9~1.1Tch, where the tightening inspection torque Tch is the inspection torque of the high-strength bolt, which is determined by the test. If it exceeds the limit, the final tightening inspection torque value of the bolt is unqualified;

[0137] 5) The number of high-strength bolts to be inspected at each node shall be 5% of the total number of bolt groups at the corresponding node, but shall not be less than two sets;

[0138] 6) For unqualified nodes, the number of unqualified nodes shall not exceed 20% of the total number of spot checks, otherwise spot checks shall be continued until 80% of the cumulative bolt group is reached, and then the under-tightened bolts shall be tightened, and the over-tightened bolts shall be replaced and re-tightened;

[0139] 7) The high-strength bolts that are inserted into the node plate on site must be initially tightened and finally tightened on the same day. The high-strength bolts after final tightening must be inspected and marked on the same day. For those that fail to meet the standards, timely handling opinions must be given, and records and visas must be kept.

[0140] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A construction method for preventing the overturning of a single curved steel box girder during hoisting, characterized in that: The method comprises the following steps: Step 1: Transport the steel box girder and assemble the steel box girder on site; Step 2: Use crane to install steel box girder construction; Step 3: When the curved box girder (3) is hoisted onto the bridge pier (1), curved steel box girder anti-overturning devices are arranged on both ends of the curved box girder (3) to prevent the curved box girder (3) from overturning; Step 4: Bolt and weld the bridge positions of the curved box girder (3) to complete the construction.

2. A construction method for preventing the overturning of a single curved steel box girder during hoisting according to claim 1, characterized in that: In step 3, the anti-overturning device of the curved steel box girder includes a crossbeam (6) and a column (9), the crossbeam (6) is arranged on the two end sides of the curved box girder (3), and the crossbeam (6) is arranged on the outside of the curved bending direction of the curved box girder (3). During hoisting, the hoisting rope is tied to the end of the curved box girder (3) and the crossbeam (6), the lower end of the column (9) is connected to the top of the pier (1), and the crossbeam (6) is connected to the top of the column (9).

3. A construction method for preventing the overturning of a single curved steel box girder during hoisting according to claim 2, characterized in that: The cross beam (6) and the arc-shaped box beam (3) are detachably arranged. When hoisting is required, the cross beam (6) is installed at both ends of the arc-shaped box beam (3). Box beam end side plates (4) are arranged outside the ends of the arc-shaped box beam (3). Box beam end side plate bolt holes (5) are arranged on the box beam end side plates (4). The cross beam (6) is connected and fixed to the box beam end side plates (4) by bolts.

4. A construction method for preventing the overturning of a single curved steel box girder during hoisting according to claim 2, characterized in that: The column (9) and the cross beam (6) are fixed by bolts, and bolt holes are arranged at both ends of the cross beam (6). The bottom end of the column (9) is pre-buried in the bridge pier (1) and is arranged vertically.

5. A construction method for preventing the overturning of a single curved steel box girder during hoisting according to claim 1, characterized in that: The specific process of on-site assembly of the steel box girder in step 1 is as follows: adopt the structural form of pier support, first set up the pier in the site, and after the steel box girder transport vehicle arrives, directly hoist the steel box girder to the top of the pier for secondary assembly. The main structure of the pier is φ219×10 steel pipe, and a 12×240×240 cover plate is set on the top. An adjusting tooth plate is placed on the cover plate to adjust the overall elevation. A 12×400×400 steel plate is set below as the base, and bolt holes are opened around it. Anchor bolts are used to firmly connect the pier to the ground. The height of the pier is 800mm; When erecting the two-piece scaffold on site, first lay out the steel box girder ground sample line according to the scaffold drawing, and set up 6 piers under each production segment, and the piers are all located under the steel box girder partition.

6. A construction method for preventing the overturning of a single curved steel box girder during hoisting according to claim 1, characterized in that: In step 2: crawler crane is used for lifting. After the steel box girder is assembled on the roadbed, the whole span is lifted into place. Four lifting eyes are arranged. The maximum weight of the segment is 80t. A safety factor of 1.2 is used. Considering that only three lifting eyes are under force, the force on each lifting eye is F=80*1.2 / 3=33t. Therefore, 30-40t lifting eyes are selected. For segments with a lifting weight of 60t or less, the force on each lifting eye is F=60*1.2 / 3=24t. Therefore, 20-30t lifting eyes are used. The principle of lifting lug arrangement is as follows: the lifting lugs are arranged at the corresponding positions on the upper part of the partition and the web, the lifting lugs are welded to the top plate, and the relative positions of four or two lifting points are placed according to the center of gravity to ensure that the four or two lifting points of the beam section are balanced in force. According to the crane model, wire rope length, beam section length, crane arm length and other working conditions, ensure that the angle between the wire rope and the steel beam section is greater than 60.

7. A construction method for preventing the overturning of a single curved steel box girder during hoisting according to claim 1, characterized in that: The process of crawler crane on-site assembly in step 2 is: unloading and installation of the main engine → installation of crawler tracks → installation of tail counterweight → assembly of main boom → insertion of hooks → lifting → setting and inspection of working conditions → no-load test; Crawler crane installation: (1) Unloading and installation of the main engine: Make sure the work site is flat and solid. Four steel plates are required, with the dimensions of 9 meters long, 2.2 meters wide, and 30 mm thick. The distance between two steel plates is 2.8 meters. The trailer carries the main engine to the assembly site, adjusts the trailer position, starts the crawler crane engine, and sets it to assembly operation mode; Pull out the outrigger positioning pin, rotate the outrigger to the working position, insert the positioning pin, place the frame outrigger disc under the outrigger oil cylinder, operate the frame outrigger oil cylinder, slowly press the outrigger oil cylinder on the outrigger disc, pay attention to prevent the outrigger disc from falling, lift the main body of the whole machine, lift the main engine component cylinder, lift it to 1.15 meters, keep it still for 3 minutes, observe safety, and then slowly drive out the trailer, and the main body is unloaded from the flatbed truck by itself and separated from the flatbed truck; (2) Install the track: Start the engine and put the main engine in standby mode. Use a ton crawler crane to lift the crawler and slowly move it close to the frame, insert the single ear on the crawler into the double ears on the frame, slowly operate the vertical cylinder of the frame to align the pin holes on the crawler frame and the frame, operate the handle on the side of the frame to fully insert the pin, fix the pin with a baffle, install the other crawler in the same way, connect the quick connector, retract the vertical cylinder, and reverse the disassembly process, assemble the left and right walking plates, adjust the cab, rotate 900, pull the A-type operating handle, and pop up the A-type frame. After checking that everything is correct, slowly lift the A-type frame to 1200 and rotate the vehicle body 900; (3) Install the tail counterweight: The crawler crane mast automatically unloads the counterweight block, and the luffing mast lifts the counterweight tray to the appropriate position to complete the installation of the counterweight block. The counterweight block and the counterweight tray are connected with a chain, and the screws on the adjustment plate are tightened to press and lock the counterweight block; (4) Assemble the main boom: Use 4 lifting belts to hoist the crawler crane main boom through the auxiliary crane, corresponding to the connection holes on the main boom rod, and then use the pinning machine to drive the connecting pin shaft into the main boom rod and insert the buckle. The installation order is the main boom rod root, 6m arm, 12m arm, 12m arm, 12m arm, 12m arm, main boom rod head. The total installation length of this main boom is 60 meters. Connect the hydraulic oil pipe of the main boom rod seat, remove the tie rod pins of the pulley block and the main boom rod seat, connect the tie rods on the pulley block and the main boom rod, remove the front tie rod locking pin shaft on the main boom rod, and connect the main boom rod cable plug at the same time. Check whether the tie rod connection is correct. After confirmation, operate the 1# winch, pull up the main boom rod, install the main boom buffer rod and buffer rod bracket, select the hook and ratio, thread the lifting wire rope, connect the electrical cable at the same time, install the height limit device and the arm end pulley, and operate the amplitude change handle to make the boom stand upright; (5) Threading the hook: Use an auxiliary crane to lift the 130t hook and place it at the designated location. Install the instructions and working conditions, reverse the traction wire rope, connect the traction wire rope with the 1# winch wire rope, operate the traction wire rope winch and the 1# winch, retract the traction wire rope while releasing the 1# winch wire rope, let the 1# winch wire rope pass through the L-bar head pulley and the hook pulley, install the wire rope anti-slip pin shaft, install the wire rope lock, install the limit device, and continue to lift the boom; (6) Lifting, organization is completed, and all assembly tools are checked to see if they are left on the boom. Check whether the length and model of the connecting pull plates between the components are correct, and check whether the safety pins of the mounting pins are complete. After checking that all components and safety pins are installed, the crane driver is instructed to slowly lift the crane boom. During the lifting process, the hook should always be on the ground. The hook can only be lifted off the ground after the main boom angle reaches more than 60°. After the inspection is qualified, the lifting operation should be carried out slowly according to the instructions. The crane working conditions are set in the computer according to the organized crane working conditions. The equipment of the crane is checked during the empty crane operation to confirm that all working parts are in good condition and operating normally. (7) No-load test: A no-load test can be carried out only after the technical inspection is passed, in order to check the correctness of the control action of the electrical equipment, the accuracy of the action of each mechanism, and to adjust each safety limit indicator device. The test content is as follows: the lifting mechanism is lifted at rated speed throughout the entire range at various amplitude positions, the empty hook is lowered three times each, the variable amplitude mechanism is within the full amplitude range, the boom is raised and lowered three times each, the slewing mechanism is in the maximum amplitude state, and the boom is rotated 360° to the left and right three times each, and the walking mechanism is within the walking range, and moves forward and backward once each time, but each continuous walking time should not exceed ten minutes.

8. A construction method for preventing a single curved steel box girder from overturning during hoisting according to claim 2, characterized in that: In step 3, before hoisting, the cross beams (6) at both ends of the arc box beam (3) are connected to the arc box beam (3) as a whole by bolts, and a φ219×8 column (9) is placed under the cross beam (6) on the concrete cap beam in advance, so that after the arc box beam (3) is hoisted into place, the center of gravity of the arc box beam (3) is within the line connecting the on-site support and the pier, so that it can play an anti-overturning role. The column (9) is fixed to the cap beam by means of a flange and anchor bolts. After the arc box beam (3) is in place, the cross beam (6) and the column (9) are welded.

9. A construction method for preventing the overturning of a single curved steel box girder during hoisting according to claim 1, characterized in that: In step 4, the specific process of bolt connection of the steel box girder bridge position is as follows: the bolt connection of the bridge position includes the bolt connection between the steel box girder segments and the bolt connection between the cross beam and the steel box girder. The installation process of the high-strength bolts is as follows: 1) After the steel beam is hoisted in place, when assembling it by the bracket method, each joint should be driven with 25% of the nails as required. When assembling the cantilever beam, each joint should be driven with 50% of the nails as required, and arranged alternately with the bolt holes. Then check whether all the bolt holes can ensure the smooth and free passage of the high bolts. If not, report to the chief engineer and the on-site supervisor, and then study and deal with it according to the specific situation. Use no less than four ordinary bolts to clamp the gap between the steel beam node connection plate surfaces. Only after they are tightly fitted can high-strength bolts be installed. If the plate surface cannot be tightly fitted, high-strength bolts cannot be installed. Report to the chief engineer and the on-site supervisor, and then study and deal with it according to the specific situation. High-strength bolts shall not be used as temporary installation bolts during the installation process. 2) Before installing high-strength bolts, the appearance of the bolts should be inspected. High-strength bolts with rust, damaged threads, damp surfaces, dust, sand, or changes in surface conditions should not be used. High-strength bolts with changed surface conditions should be sent back to the original manufacturer for re-surface treatment. After re-treatment, they should be re-inspected according to the original supply requirements and can only be used after passing the inspection; 3) When installing high-strength bolts, there is a washer on each side of the bolt head and the nut. The chamfered side of the washer faces the bolt head and the nut support surface respectively; the marked side of the nut faces outwards; 4) In order to facilitate construction and improve the appearance of the entire bridge, the installation direction of high-strength bolts is specified as follows: (a) The nuts of the high-strength bolts on all main beam facades of the bridge shall be installed on the outside of the gusset plate; (b) When the nut position of high-strength bolts in individual parts cannot meet the above requirements, the project chief engineer may be consulted to determine the direction of the bolts. The direction of insertion should be based on the principles of ease of tightening, good appearance and consistency of the entire bridge; 5) When installing high-strength bolts, the bolts should be inserted into the holes smoothly and should not be knocked in by force. A certain number of positioning pins should be punched first to ensure that the gaps overlap before installing the bolts. If the bolts cannot be inserted freely, the holes should be trimmed with a reamer. The maximum diameter of the hole after trimming should be less than 1.2 times the bolt diameter. When repairing the holes, in order to prevent iron filings from falling into the gaps between the plates, all the bolts around should be tightened before reaming the holes, so that the plates are closely attached before repairing. It is strictly forbidden to use gas cutting to expand the holes. If the bolts cannot be inserted freely after the holes are reamed to 1.2 times the bolt diameter, the splicing plates should be re-assembled. 6) The axis of the installed high-strength bolts should be perpendicular to the surface of the node plate. Otherwise, find out the reason and reinstall; Tightening of high-strength bolts: 1) The high-strength bolts of this bridge are tightened by the torque method and controlled by the torque method. That is, based on a series of process tests, the tightening of high-strength bolts is divided into two stages: initial tightening and final tightening. High-strength bolt installation steps: (a) Install high-strength bolts corresponding to the bolt holes that have neither punches nor ordinary bolts installed. The installation sequence is from the center of the node to the surrounding area, and tighten them with a plum wrench; (b) Replace ordinary bolts with high-strength bolts one by one, starting from the center of the node and moving toward the surrounding areas, and tighten them simultaneously with a plum wrench; (c) Use a calibrated initial tightening wrench to initially tighten the high-strength bolts that have been tightened with a box spanner, 50% of the final tightening torque, and make initial tightening marks. The tightening sequence should spread from the center of the node to the surrounding areas; (d) Remove the punches in batches, replace them with high-strength bolts, and perform initial tightening, 50% of the final tightening torque, and use a blue paint pen to mark the initial tightening; (e) All high-strength bolts that have been initially tightened shall be tightened to a final torque of 100%, with the tightening sequence spreading from the center of the node to the surrounding areas, and the final tightening mark shall be made with red paint. The initial tightening and final tightening shall be completed on the same working day; (f) Within 24 hours after the final tightening, the bolts tightened on that day shall be checked according to the specified quantity using a dial wrench and marked with yellow paint; 3) Initial tightening: After the high-strength bolts are installed into the bolt holes and checked to be correct, tighten them with an ordinary plum-shaped manual wrench first, and then use a calibrated electric wrench to tighten the bolts to 50% of the final tightening torque to complete the initial tightening; 4) For high-strength bolts that have been initially tightened, a straight line should be immediately drawn on the nut, washer and plate surface with a blue marker to prevent repeated tightening, omissions and facilitate inspection; 5) Final tightening: The final tightening torque value of each batch of high-strength bolts is determined by the following formula: TC=K×PC×d In the formula: TC is the final tightening torque value of the high-strength bolt, PC is the construction pre-tension value of the high-strength bolt, K is the average value of the torque coefficient of each batch of high-strength bolts, d is the nominal diameter of the high-strength bolt, and the average value K of the torque coefficient of the high-strength bolt in the formula is determined by the test; 6) Final tightening is completed by a calibrated electric torque wrench. For bolts in some parts where electric tools cannot be used, a calibrated dial inspection wrench or a manual wrench with a sound is used to complete the final tightening; 7) During the tightening process of high-strength bolts, the bolt head and washer shall not rotate with the nut. If the bolt or washer is found to rotate, the high-strength bolt shall be replaced and the initial tightening and final tightening operations shall be repeated. The replaced high-strength bolts shall be returned to the warehouse and sent back to the factory for centralized processing. They can only be used after passing the acceptance inspection. It is strictly forbidden to use them directly again; 8) When tightening high-strength bolts, the use of manual torque wrenches must be uniform, and impact force must not be used. When the electric torque wrench is started, it must be operated continuously and smoothly until the electric wrench stops automatically. After the electric wrench stops automatically, it is strictly forbidden to start the electric wrench again to tighten the bolt to prevent over-tightening; 9) Whether in the initial tightening or final tightening stage, or when using different wrenches, the tightening sequence should generally be from the center of the bolt group to the surrounding area. If this cannot be followed for special parts, report to the chief engineer for further processing; 10) During construction, the electric wrench should use an independent power supply or a voltage-stabilized power supply to reduce voltage fluctuations that affect the output stability of the electric wrench torque; 11) If any abnormality or failure occurs during the use of various wrenches, on-site construction personnel shall not handle them without authorization, and must immediately stop construction, hand over the wrench to the high-strength bolt test team for inspection and repair, and report the failure so that corresponding measures can be formulated to deal with the on-site bolts; High-strength bolt construction quality inspection: (1) According to the relevant regulations on the construction quality inspection of high-strength bolts, the construction quality inspection of high-strength bolts should be carried out by specialized test and inspection personnel, with the cooperation of construction personnel, and completed within 4-24 hours after the final tightening of the high-strength bolts; For the initial tightening check, use a 0.3kg hammer to hit each nut one by one, and press the opposite side of the nut with your finger. If the finger feels that the nut vibrates too much or is loose, it means that the bolt is under-tightened or missed, and needs to be re-tightened, or the initial tightening method is used for confirmation, that is, the three states of initial tightening, final tightening, and inspection are marked with three different colors of paint: blue, red, and white. (2) Final tightening inspection of high-strength bolts: Final tightening inspection shall be carried out with a calibrated torque inspection wrench, and its accuracy error shall be less than 3% of the torque value of the wrench; 1) Before checking with a torque check wrench, visually check the misalignment of the markings when the initial tightening is completed to determine whether there is any missing tightening during the final tightening and whether the gasket or bolt has rotated. If the markings are not misaligned, it means that the bolt is missing. If the misalignment is too large, the bolt may be over-tightened or the gasket may slip, which should be checked; 2) The final tightening torque inspection is carried out by the tightening method, that is, the nut is tightened along the tightening direction with a pointer dial inspection wrench for the final tightened high-strength bolt. The inspector evenly applies force to the wrench handle to increase the torque indication at a uniform speed and the pointer rotates smoothly. When the pointer pauses, it means that the torque value has caused the nut to rotate slightly, and this torque value is the final tightening inspection torque value of the bolt; 3) Before the tightening inspection, draw a thin line on the nut and washer to monitor the rotation of the nut. To prevent the bolt head from rotating with the nut during the inspection, which may cause misjudgment, the inspector should pay attention and bring a locking tool; 4) The on-site inspection torque value should be within 0.9~1.1Tch, where the tightening inspection torque Tch is the inspection torque of the high-strength bolt, which is determined by the test. If it exceeds the limit, the final tightening inspection torque value of the bolt is unqualified; 5) The number of high-strength bolts to be inspected at each node shall be 5% of the total number of bolt groups at the corresponding node, but shall not be less than two sets; 6) For unqualified nodes, the number of unqualified nodes shall not exceed 20% of the total number of spot checks, otherwise spot checks shall be continued until 80% of the cumulative bolt group is reached, and then the under-tightened bolts shall be tightened, and the over-tightened bolts shall be replaced and re-tightened; 7) The high-strength bolts that are inserted into the node plate on site must be initially tightened and finally tightened on the same day. The high-strength bolts after final tightening must be inspected and marked on the same day. For those that fail to meet the standards, timely handling opinions must be given, and records and visas must be kept.

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