Hoisting construction method for changing gravity center of arc-shaped lane steel box girder

Abstract

The invention provides a hoisting construction method for changing the gravity center of an arc-shaped lane steel box girder, and belongs to the technical field of arc-shaped box girder hoisting construction. 2, transporting the arc-shaped box girder and splicing the arc-shaped box girder on site; 3, the arc-shaped box girder is installed through a crane for construction; and 4, bridge position bolt connection and bridge position welding connection are conducted on the arc-shaped box beam, and construction is completed. In the construction process, the gravity center balancing devices are arranged at the end portions of the two or more arc-shaped box girders, so that the gravity center positions of the arc-shaped box girders are changed, the gravity center balancing devices can connect the end portions of all the arc-shaped box girders into a whole, and the centers of the arc-shaped box girders are always transferred to the middle position of a lane; meanwhile, due to the fact that the gravity center balancing device is horizontally arranged at the outer end, maintenance is very easy at ordinary times.

Description

Technical Field

[0001] The invention relates to the technical field of arc box girder hoisting construction, and in particular to a hoisting construction method for changing the center of gravity of an arc lane steel box girder. Background Art

[0002] The curved box girder (3) has good bending resistance, reliable torsion resistance and large spanning capacity, and has been widely used in the design of urban bridges with limited land use. However, its light weight is not conducive to the lateral anti-overturning of the structure. In particular, it is prone to overturning during the hoisting process.

[0003] The Chinese patent with the announcement number CN213653170U discloses an anti-overturning structure suitable for a small radius curved arc box girder (3), comprising a bridge pier body and a small radius curved arc box girder (3); 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 arc box girder (3); 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 arc box girder (3); 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. The device is used to fix the box girder in a later stage to prevent it from overturning, but during hoisting, since the center of the curved box girder is not on the connecting line of the two fulcrums, it is easy to overturn. At the same time, after the hoisting is completed, the existing structure is to fix each curved box girder (3) at the position of the bridge pier. This structure can only play a fixing role, but the center of gravity of the curved box girder (3) is still in the suspended position on the side, and it can no longer support the connection line of the pier, which is still easy to cause overturning in the later stage. The existing hoisting method is to add bolts to the two ends of each curved box girder vertically after hoisting and fixing. The support point is still at the original position, and the width of the support is not changed, so that the center of the curved box girder remains unchanged. This fixing method has a short practical life because the center of gravity is always on the outside of the connection line, and the bolts are subjected to relatively large forces. Therefore, it is necessary to design a hoisting construction method for changing the center of gravity of the curved lane steel box girder. Summary of the invention

[0004] The purpose of the present invention is to provide a hoisting construction method for changing the center of gravity of a curved roadway steel box girder, so as to solve the technical problem that the center of gravity of the existing curved roadway curved box girder (3) is offset and prone to overturning.

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

[0006] A hoisting construction method for changing the center of gravity of a curved lane steel box girder, the method comprising the following steps:

[0007] Step 1: Divide the curved box girder into sections;

[0008] Step 2: Transport the curved box beam and assemble it on site;

[0009] Step 3: Use a crane to install the curved box girder;

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

[0011] Furthermore, in step 1, the curved box girder is transversely segmented, and the curved box girder is transversely divided into steel main beams, inter-box cross beams and cantilevers. The curved box girder of ramp A bridge is transversely segmented, and all ramp A bridges are standard sections. The whole bridge adopts a double-sided box design, and is transversely divided into 5 sections according to the main beam, cantilever arm and cross beam;

[0012] The curved box girder of the B ramp bridge is divided into sections horizontally: The B ramp bridge is all standard sections, and the whole bridge adopts a double-sided box design. It is divided into 5 sections horizontally according to the main beam, cantilever arm, and cross beam;

[0013] Transverse segmentation of the curved box girder of the C ramp bridge: The standard double-sided box section of the C ramp bridge adopts the same segmentation method as the curved box girders of the other two ramps, which is divided into 5 sections transversely, the widening section 3 main beam section is divided into 7 sections, and the 4 main beam section is divided into 9 sections;

[0014] Longitudinal segmentation of curved box girder: The curved box girder of ramp A has a span of 40+3×37m. Each span is longitudinally divided into three sections: A, B, and C. The lengths of the 40m span are 13m, 13m, and 14m respectively, and the lengths of the 37m span are 12m, 12m, and 13m respectively. The whole bridge is divided into 24 sections of steel main beams, 24 sections of cantilever arms, and 53 sections of box beams.

[0015] B ramp bridge curved box girder longitudinal: B ramp bridge span is arranged as 35+40+4×28+3×28+30m, each span is longitudinally divided into three sections: A, B and C. The lengths of the 40m span are 13m, 14m and 13m respectively, the lengths of the 35m span are 12m, 11m and 12m respectively, the lengths of the 30m span are 9.5m, 11m and 9.5m respectively, the lengths of the 28m span are 9m, 10m and 9m respectively. The whole bridge is divided into 60 sections of steel main beams, 60 sections of cantilever arms and 108 sections of box beams;

[0016] The C ramp span is arranged as 4×30+3×30+30+45+30m. The 45m span is longitudinally divided into 5 sections: A, B, C, D, and E, with lengths of 8m, 8m, 13m, 8m, and 8m respectively. The 30m span is divided into 3 sections: A, B, and C, with lengths of 9.5m, 11m, and 9.5m respectively. The entire bridge is divided into 90 steel main beams, 60 cantilever arms, and 220 box beams.

[0017] Furthermore, in step 2, a pier-supported structure is adopted. The pier is first set up in the site. After the arc box girder transport vehicle arrives, the arc box girder is directly hoisted to the top of the pier for secondary assembly. The main structure of the pier is a φ219×10 steel pipe, a 12×240×240 cover plate is set on the top, and 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;

[0018] When erecting the two-piece scaffold on site, first lay out the curved 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 diaphragm of the curved box girder.

[0019] Further, in step 3, crawler crane is used for lifting. After the arc box girder is assembled on the roadbed, the whole span is lifted into place, and 4 lifting lugs are arranged. The maximum weight of the segment is 80t. A safety factor of 1.2 is used. Considering that only 3 lifting lugs are subjected to force, the force on each lifting lug is F=80*1.2 / 3=33t, so 30-40t lifting lugs are selected. For segments with a lifting weight of 60t or less, the force on each lifting lug is F=60*1.2 / 3=24t, so 20-30t lifting lugs are used;

[0020] 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.

[0021] Furthermore, the process of on-site assembly of the crawler crane in step 3 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;

[0022] Crawler crane installation:

[0023] (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;

[0024] 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;

[0025] (2) Install the track:

[0026] Start the engine and put the main engine in standby mode.

[0027] 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;

[0028] (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;

[0029] (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;

[0030] (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;

[0031] (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.

[0032] (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.

[0033] Further, in step 3, in the arc box girder hoisting: the first part: the first round of arc box girder assembly includes assembling 1#, a total of 5 hoisting segments, the second round of arc box girder assembly includes assembling 2#, a total of 5 hoisting segments, the second part: the third round of arc box girder assembly includes assembling 3#, 4#, 5#, a total of 18 hoisting segments, the fourth round of arc box girder assembly includes assembling 6#, 7#, 8#, a total of 16 hoisting segments, the third part: the fifth round of arc box girder assembly includes assembling 9#, 10#, a total of 12 hoisting segments;

[0034] The specific process of lifting is:

[0035] Step 1: The crawler crane lifts the LA1 segment under the super-lift tower arm working condition. At this time, the crawler crane has a lifting radius of 34m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, and then slowly lowers the beam;

[0036] Step 2: The crawler crane lifts the RA1 segment. At this time, the crawler crane has a lifting radius of 34m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0037] Step 3: The crawler crane lifts the RC1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, and then slowly lowers the beam.

[0038] Step 4: The crawler crane lifts the LC1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0039] Step 5: The crawler crane lifts the RB1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, and then slowly lowers the beam.

[0040] Step 6: The crawler crane lifts the LB1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0041] Step 7: The crawler crane lifts the C8A segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, and then slowly lowers the beam.

[0042] Step 8: The crawler crane lifts the C8B segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0043] Step 9: The crawler crane lifts the C8C segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0044] Step 10: The crawler crane lifts the RB8 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, and then slowly lowers the beam.

[0045] Step 11: The crawler crane lifts the LB8 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes;

[0046] Step 12: The crawler crane lifts the C7A segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, and then slowly lowers the beam.

[0047] Step 13: The crawler crane lifts the C7B and C7C segments. At this time, the crawler crane has a lifting radius of 36m. After adjusting the position of the curved box beam, the beam is slowly lowered and the cross-connection between the boxes is lifted.

[0048] Step 14: The crawler crane lifts the C6A and C6B segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, and then slowly drops the girder and lifts the cross-connection between the boxes.

[0049] Step 15: The crawler crane lifts the C6C and C6D segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0050] Step 16: The crawler crane lifts the RB6 and LB6 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the beam, and lifts the cross-connection between the boxes.

[0051] Step 17: The crawler crane lifts the C5A and C5B segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0052] Step 18: The crawler crane lifts the C5C and C5D segments. At this time, the crawler crane has a lifting radius of 22m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, and then slowly drops the girder and lifts the cross-connection between the boxes.

[0053] Step 19: The crawler crane lifts the LB5 and RB5 segments. At this time, the crawler crane has a lifting radius of 22m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0054] Step 20: The crawler crane lifts the LA4 and RA4 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes;

[0055] Step 21: The crawler crane lifts the LC4 and RC4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes;

[0056] Step 22: The crawler crane lifts the LC4 and RC4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0057] Step 23: The crawler crane lifts the LC4 and RC4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0058] Step 24: The crawler crane lifts the LB4 and RB4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0059] Step 25: The crawler crane lifts the LA4 and RA4 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0060] Step 26: The crawler crane lifts the LB2 and RB2 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, and then slowly drops the girder and lifts the cross-connection between the boxes.

[0061] Step 27: The crawler crane lifts the LC2 and RC2 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0062] Step 28: The crawler crane lifts the LA2 and RA2 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder, slowly drops the girder, and lifts the cross-connection between the boxes.

[0063] Step 29: The crawler crane lifts the C9A, C9B, and C9C segments. At this time, the crawler crane has a lifting radius of 40m. After adjusting the position of the curved box beam, the beam is slowly lowered and the cross-connection between the boxes is lifted;

[0064] Step 30: The crawler crane lifts the LB9 and RB9 segments. At this time, the crawler crane has a lifting radius of 40m. After adjusting the position of the curved box beam, the beam is slowly lowered and the cross-connection between the boxes is lifted;

[0065] Step 31: The crawler crane lifts the C10A, C10B, and C10C segments. At this time, the crawler crane has a lifting radius of 38m. After adjusting the position of the curved box beam, the beam is slowly lowered and the cross-connection between the boxes is lifted;

[0066] Step 32: The crawler crane lifts the LB10 and RB10 segments. At this time, the crawler crane has a lifting radius of 26m. After adjusting the position of the curved box girder, it slowly lowers the beam and lifts the cross-connection between the boxes.

[0067] Further, in step 3, a center of gravity balancing device is arranged between the ends of two adjacent curved box girders, and the center of gravity balancing device includes two box girder end side plates and a cross beam, the two box girder end side plates are respectively arranged on adjacent sides of the two adjacent curved box girders, the cross beam and the two box girder end side plates (4) are detachably arranged, the box girder end side plates are provided with box girder end side plate bolt holes, and the two ends of the cross beam (6) are respectively provided with a cross beam first end bolt hole and a cross beam second end bolt hole, and the cross beam first end bolt hole and the cross beam second end bolt hole are respectively fixed by setting bolts and threadedly connecting with the box girder end side plate bolt holes.

[0068] Furthermore, the center of gravity balancing device further comprises a column. When the first curved box girder is installed, one end of the center of gravity balancing device is arranged on the first curved box girder, the upper end of the column is connected to the bottom of the other end of the center of gravity balancing device, and the bottom of the column is arranged on the bridge pier.

[0069] Before hoisting, the cross beams at both ends of the curved box beam are connected to the curved box beam with bolts to form a whole. φ219×8 columns are placed under the cross beams on the concrete cap beam in advance. 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, which can prevent overturning. The columns are fixed to the cap beam with flanges and anchor bolts. After the curved box beam is in place, the cross beams are welded to the columns.

[0070] Furthermore, in step 4, the specific process of bolt connection of the arc box girder bridge position is as follows: the bolt connection of the bridge position includes bolt connection between arc box girder segments and bolt connection between the cross beam and the arc box girder, and the installation process of the high-strength bolts is as follows:

[0071] 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.

[0072] 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;

[0073] 3) When installing high-strength bolts, there is a washer on each side of the bolt head and the nut, with the chamfered side of the washer facing the bolt head and the nut support surface respectively; the marked side of the nut faces outwards;

[0074] 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:

[0075] (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;

[0076] (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;

[0077] 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.

[0078] 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;

[0079] Tightening of high-strength bolts:

[0080] 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.

[0081] High-strength bolt installation steps:

[0082] (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;

[0083] (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;

[0084] (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;

[0085] (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;

[0086] (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;

[0087] (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;

[0088] 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;

[0089] 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 board pen to prevent repeated tightening, omissions and facilitate inspection;

[0090] 5) Final tightening: The final tightening torque value of each batch of high-strength bolts is determined by the following formula:

[0091] TC=K×PC×d

[0092] 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;

[0093] 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;

[0094] 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;

[0095] 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;

[0096] 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;

[0097] 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;

[0098] 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;

[0099] High-strength bolt construction quality inspection:

[0100] (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;

[0101] 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.

[0102] (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;

[0103] 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;

[0104] 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;

[0105] 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;

[0106] 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;

[0107] 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;

[0108] 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;

[0109] 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.

[0110] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0111] (1) The construction process of the present invention changes the center of gravity position of the curved box beam by setting a center of gravity balancing device at the end positions of two or more curved box beams. Because the center of gravity balancing device can connect all the ends of the curved box beams into a whole, the center of the curved box beam is often transferred to the middle position of the lane, so that the curved box beam on the lane will not overturn. At the same time, because the center of gravity balancing device is horizontally set at the outer end, it is very simple to perform routine maintenance.

[0112] (2) The present invention has high construction efficiency and a short construction period, and can ensure safety during the construction process, thereby avoiding the situation in which the center of gravity of the arc box girder is difficult to find, difficult to install, and difficult to maintain in the later stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0113] Figure 1 This is a flow chart of the on-site construction process of the curved box girder of the present invention;

[0114] Figure 2 It is a classification diagram of the on-site hoisting of the Dashanshu Interchange in an embodiment of the present invention;

[0115] Figure 3 This is the layout diagram of the first round of assembly site of the Dashanshu Interchange steel box girder according to an embodiment of the present invention;

[0116] Figure 4 This is a layout diagram of the second round of assembly site of the Dashanshu Interchange steel box girder according to an embodiment of the present invention;

[0117] Figure 5This is a layout diagram of the third round of assembly site of the Dashanshu Interchange steel box girder according to an embodiment of the present invention;

[0118] Figure 6 This is a layout diagram of the fourth round of assembly site of the Dashanshu Interchange steel box girder according to an embodiment of the present invention;

[0119] Figure 7 This is a layout diagram of the fifth wheel assembly site of the Dashanshu Interchange steel box girder according to an embodiment of the present invention;

[0120] Figure 8 It is a schematic diagram of the end structure when a single box girder is hoisted according to the present invention;

[0121] Fig. 9 It is a schematic diagram of the connection structure of two box beams of the present invention.

[0122] 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-middle connecting square steel. DETAILED DESCRIPTION

[0123] 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.

[0124] like Figure 1 As shown, a hoisting construction method for changing the center of gravity of a curved lane steel box girder comprises the following steps:

[0125] Step 1: Segment the curved box girder 3. The curved box girder 3 is transversely segmented. The curved box girder 3 is transversely divided into steel main beams, inter-box cross beams and cantilevers. The curved box girder 3 of ramp A is transversely segmented. The ramp A bridge is a standard section. The whole bridge adopts a double-sided box design. It is transversely divided into 5 sections according to the main beam, cantilever arm and cross beam.

[0126] The curved box girder of the B ramp bridge is divided into 3 transverse sections: The B ramp bridge is all standard sections, and the whole bridge adopts a double-sided box design. It is divided into 5 sections in the transverse direction according to the main beam, cantilever arm, and cross beam;

[0127] C ramp bridge curved box girder 3 transverse segmentation: C ramp bridge transverse segmentation standard double-sided box section adopts the same segmentation method as the other two ramp curved box girders 3, which is divided into 5 sections transversely, the widening section 3 main beam section is divided into 7 sections, and the 4 main beam section is divided into 9 sections;

[0128] Curved box girder 3 longitudinal segmentation: Curved box girder 3 of ramp A, the span of ramp A is 40+3×37m, each span is longitudinally divided into three sections: A, B, and C. The lengths of the 40m span are 13m, 13m, and 14m respectively, and the lengths of the 37m span are 12m, 12m, and 13m respectively. The whole bridge is divided into 24 steel main beams, 24 cantilever arms, and 53 box beams;

[0129] The arc box girder of the B ramp bridge is arranged as 35+40+4×28+3×28+30m. Each span is divided into three sections, A, B and C. The lengths of the 40m span are 13m, 14m and 13m respectively; the lengths of the 35m span are 12m, 11m and 12m respectively; the lengths of the 30m span are 9.5m, 11m and 9.5m respectively; the lengths of the 28m span are 9m, 10m and 9m respectively. The whole bridge is divided into 60 sections of steel main beams, 60 sections of cantilever arms and 108 sections of box beams.

[0130] The C ramp span is arranged as 4×30+3×30+30+45+30m. The 45m span is longitudinally divided into 5 sections: A, B, C, D, and E, with lengths of 8m, 8m, 13m, 8m, and 8m respectively. The 30m span is divided into 3 sections: A, B, and C, with lengths of 9.5m, 11m, and 9.5m respectively. The entire bridge is divided into 90 steel main beams, 60 cantilever arms, and 220 box beams.

[0131] Step 2: Transport and assemble the curved box girder 3 on site. The pier-supported structure is adopted. The piers are set up in the site first. After the transport vehicle of the curved box girder 3 arrives, the curved box girder 3 is directly hoisted 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. The 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. 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.

[0132] When erecting the two-piece scaffold on site, first lay out the ground sample line of the curved box girder 3 according to the scaffold drawing, and set 6 piers under each production segment, and the piers are all located under the partition of the curved box girder 3.

[0133] Step 3: Use a crane to install the curved box girder 3. The crawler crane is used for lifting. After the curved box girder 3 is assembled on the roadbed, the entire span is hoisted 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 stressed, the force on each lifting eye is F = 80*1.2 / 3 = 33t. Therefore, a 30-40t lifting eye is 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, a 20-30t lifting eye is used.

[0134] 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.

[0135] 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;

[0136] Crawler crane installation:

[0137] (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;

[0138] 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;

[0139] (2) Install the track:

[0140] Start the engine and put the main engine in standby mode.

[0141] 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;

[0142] (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;

[0143] (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;

[0144] (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;

[0145] (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.

[0146] (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.

[0147] Curved box girder 3 is being hoisted: Figure 2As shown, the first part: the first round of assembly of curved box beam 3 includes assembly of 1#, totaling 5 lifting segments, the second round of assembly of curved box beam 3 includes assembly of 2#, totaling 5 lifting segments, the second part: the third round of assembly of curved box beam 3 includes assembly of 3#, 4#, 5#, totaling 18 lifting segments, the fourth round of assembly of curved box beam 3 includes assembly of 6#, 7#, 8#, totaling 16 lifting segments, the third part: the fifth round of assembly of curved box beam 3 includes assembly of 9#, 10#, totaling 12 lifting segments, as shown Figure 3-7 shown.

[0148] The specific process of lifting is:

[0149] Step 1: The crawler crane lifts the LA1 segment in the super-lift tower arm working condition. At this time, the crawler crane has a lifting radius of 34m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly lowers the beam;

[0150] Step 2: The crawler crane lifts the RA1 segment. At this time, the crawler crane has a lifting radius of 34m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0151] Step 3: The crawler crane lifts the RC1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly lowers the beam.

[0152] Step 4: The crawler crane lifts the LC1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0153] Step 5: The crawler crane lifts the RB1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly lowers the beam.

[0154] Step 6: The crawler crane lifts the LB1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0155] Step 7: The crawler crane lifts the C8A segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly lowers the beam.

[0156] Step 8: The crawler crane lifts the C8B segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0157] Step 9: The crawler crane lifts the C8C segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0158] Step 10: The crawler crane lifts the RB8 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly lowers the beam.

[0159] Step 11: The crawler crane lifts the LB8 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0160] Step 12: The crawler crane lifts the C7A segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly lowers the beam.

[0161] Step 13: The crawler crane lifts the C7B and C7C segments. At this time, the crawler crane has a lifting radius of 36m. After adjusting the position of the curved box girder 3, it slowly drops the beam and lifts the cross-connection between the boxes.

[0162] Step 14: The crawler crane lifts the C6A and C6B segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0163] Step 15: The crawler crane lifts the C6C and C6D segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0164] Step 16: The crawler crane lifts the RB6 and LB6 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0165] Step 17: The crawler crane lifts the C5A and C5B segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0166] Step 18: The crawler crane lifts the C5C and C5D segments. At this time, the crawler crane has a lifting radius of 22m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes;

[0167] Step 19: The crawler crane lifts the LB5 and RB5 segments. At this time, the crawler crane has a lifting radius of 22m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes;

[0168] Step 20: The crawler crane lifts the LA4 and RA4 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0169] Step 21: The crawler crane lifts the LC4 and RC4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0170] Step 22: The crawler crane lifts the LC4 and RC4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0171] Step 23: The crawler crane lifts the LC4 and RC4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0172] Step 24: The crawler crane lifts the LB4 and RB4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0173] Step 25: The crawler crane lifts the LA4 and RA4 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0174] Step 26: The crawler crane lifts the LB2 and RB2 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0175] Step 27: The crawler crane lifts the LC2 and RC2 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0176] Step 28: The crawler crane lifts the LA2 and RA2 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder 3 reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder 3, and then slowly drops the beam and lifts the cross-connection between the boxes.

[0177] Step 29: The crawler crane lifts the C9A, C9B, and C9C segments. At this time, the crawler crane has a lifting radius of 40m. After adjusting the position of the curved box girder 3, it slowly drops the beam and lifts the cross-connection between the boxes.

[0178] Step 30: The crawler crane lifts the LB9 and RB9 segments. At this time, the crawler crane has a lifting radius of 40m. After adjusting the position of the curved box girder 3, it slowly drops the beam and lifts the cross-connection between the boxes.

[0179] Step 31: The crawler crane lifts the C10A, C10B, and C10C segments. At this time, the crawler crane has a lifting radius of 38m. After adjusting the position of the curved box girder 3, the beam is slowly lowered and the cross-connection between the boxes is lifted;

[0180] Step 32: The crawler crane lifts the LB10 and RB10 segments. At this time, the crawler crane has a lifting radius of 26m. After adjusting the position of the curved box girder 3, it slowly drops the beam and lifts the cross-connection between the boxes.

[0181] A center of gravity balancing device is arranged between the ends of two adjacent curved box girders 3, and the center of gravity balancing device includes two box girder end side plates 4 and a cross beam 6. The two box girder end side plates 4 are respectively arranged on adjacent sides of the two adjacent curved box girders 3, and the cross beam 6 and the two box girder end side plates 4 are detachably arranged. Box girder end side plate bolt holes 5 are arranged on the box girder end side plates 4, and cross beam 6 has cross beam first end bolt holes 7 and cross beam second end bolt holes 8 at both ends respectively. The cross beam first end bolt holes 7 and cross beam second end bolt holes 8 are respectively fixed by threading and connecting with the box girder end side plate bolt holes 5 through bolts.

[0182] The center of gravity balancing device further includes a column 9. When the first curved box girder 3 is installed, one end of the center of gravity balancing device is arranged on the first curved box girder 3, the upper end of the column 9 is connected to the bottom of the other end of the center of gravity balancing device, and the bottom of the column 9 is arranged on the pier 1.

[0183] Before hoisting, the cross beams 6 at both ends of the curved box girder 3 are connected to the curved box girder 3 as a whole with bolts, and the φ219×8 columns 9 are placed under the cross beams 6 on the concrete cap beam in advance, so that after the curved box girder 3 is hoisted into place, the center of gravity of the curved box girder 3 is within the line connecting the on-site support and the pier, so that it can play an anti-overturning role. The columns 9 are fixed to the cap beam with flanges and anchor bolts. After the curved box girder 3 is in place, the cross beam 6 and the columns 9 are welded.

[0184] During installation, the connection line of the two support flanges 2 is not in a straight line with the center of gravity of the arc box beam, and the deviation is relatively large. If it is not fixed during installation, the arc 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 of the arc box beam, maintaining balance. Fig. 9As shown, by connecting the middle positions of the two curved box beams 3 together, the center of gravity of the outward curved box beam is moved backward, and the front one is moved forward, so that the center is in the middle of the four supporting piers, so that the curved box beam 3 will not overturn.

[0185] The center of gravity balancing device includes two box beam end side plates 4 and a cross beam 6. The two box beam end side plates 4 are respectively arranged on adjacent sides of two adjacent arc-shaped box beams 3, and the cross beam 6 and the two box beam end side plates 4 are detachably arranged. The box beam end side plates 4 are connected to the cross beam 6, which is more convenient for connection during hoisting and has higher efficiency. At the same time, overturning will not occur during single hoisting.

[0186] The end side plate 4 of the box beam is integrally arranged with the end side of the arc-shaped box beam 3. The integral arrangement makes it more stable, and the bolts only need to be installed once, which makes it more sturdy and durable. The end side plate 4 of the box beam is provided with a box beam end side plate bolt hole 5, and the two ends of the cross beam 6 are respectively provided with a cross beam first end bolt hole 7 and a cross beam second end bolt hole 8, and the cross beam first end bolt hole 7 and the cross beam second end bolt hole 8 are respectively fixed by setting bolts and threadedly connected with the end side plate bolt hole 5 of the box beam. When the bolts are connected, nuts are set to fix them, and a corresponding number of nuts are set according to the acceptance of the box beam. The middle bottom of several arc-shaped box beams 3 is provided with an intermediate connecting square steel 10, and the intermediate connecting square steel 10 fixes several arc-shaped box beams 3 into one. By setting the intermediate connecting square steel 10, all the arc-shaped box beams 3 can become a whole, avoiding movement, and the acceptance effect is better. The center of gravity balancing device also includes a column 9. When the first curved box girder 3 is installed, one end of the center of gravity balancing device is arranged on the first curved box girder 3, the upper end of the column 9 is connected to the bottom of the other end of the center of gravity balancing device, and the bottom of the column 9 is arranged on the pier 1. The column 9 is mainly arranged to facilitate the installation of the first box girder, and is not needed later, and can be directly removed after installation.

[0187] A center of gravity balancing device is set at the end position of the curved box girder to change the center of gravity position of the curved box girder. Because the center of gravity balancing device can connect all the ends of the curved box girder as a whole, the center of the curved box girder is often transferred to the middle position of the lane, so that the curved box girder on the lane will not overturn.

[0188] Step 4: Complete the construction by bolting and welding the curved box girder 3 bridge positions. The specific process of bolting the curved box girder 3 bridge positions is as follows: The bridge position bolting includes bolting between the 3 segments of the curved box girder and bolting between the cross beam and the 3 curved box girder. The installation process of high-strength bolts is as follows:

[0189] 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.

[0190] 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;

[0191] 3) When installing high-strength bolts, there is a washer on each side of the bolt head and the nut, with the chamfered side of the washer facing the bolt head and the nut support surface respectively; the marked side of the nut faces outwards;

[0192] 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:

[0193] (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;

[0194] (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;

[0195] 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.

[0196] 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;

[0197] Tightening of high-strength bolts:

[0198] 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.

[0199] High-strength bolt installation steps:

[0200] (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;

[0201] (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;

[0202] (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;

[0203] (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;

[0204] (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;

[0205] (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;

[0206] 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;

[0207] 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 board pen to prevent repeated tightening, omissions and facilitate inspection;

[0208] 5) Final tightening: The final tightening torque value of each batch of high-strength bolts is determined by the following formula:

[0209] TC=K×PC×d

[0210] 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;

[0211] 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;

[0212] 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;

[0213] 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;

[0214] 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;

[0215] 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;

[0216] 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;

[0217] High-strength bolt construction quality inspection:

[0218] (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;

[0219] 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.

[0220] (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;

[0221] 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;

[0222] 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;

[0223] 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;

[0224] 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;

[0225] 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;

[0226] 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;

[0227] 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.

[0228] 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 hoisting construction method for changing the center of gravity of a curved lane steel box girder, characterized in that: The method comprises the following steps: Step 1: Divide the curved box girder (3) into sections; Step 2: transporting the curved box girder (3) and assembling the curved box girder (3) on site; Step 3: Use a crane to install the curved box girder (3); Step 4: Bolt and weld the bridge positions of the curved box girder (3) to complete the construction.

2. A method for hoisting and constructing a curved lane steel box girder to change its center of gravity according to claim 1, characterized in that: In step 1, the curved box girder (3) is transversely divided into sections. The curved box girder (3) is transversely divided into steel main beams, inter-box cross beams and cantilever arms. The curved box girder (3) of ramp A bridge is transversely divided into sections. The ramp A bridge is a standard section. The whole bridge adopts a double-sided box design. It is transversely divided into 5 sections according to the main beam, cantilever arm and cross beam. B ramp bridge curved box girder (3) Horizontal segmentation: B ramp bridges are all standard sections. The entire bridge adopts a double-sided box design and is horizontally divided into 5 sections according to the main beam, cantilever arm, and cross beam; C ramp bridge curved box girder (3) transverse segmentation: The C ramp bridge transverse segmentation standard double-sided box section adopts the same segmentation method as the other two ramp curved box girders (3), which is divided into 5 sections transversely, the widening section 3 main beam section is divided into 7 sections, and the 4 main beam section is divided into 9 sections; Longitudinal segmentation of curved box girder (3): The curved box girder (3) of ramp A has a span of 40+3×37m. Each span is longitudinally divided into three sections: A, B, and C. The lengths of the 40m span are 13m, 13m, and 14m respectively, and the lengths of the 37m span are 12m, 12m, and 13m respectively. The whole bridge is divided into 24 steel main beams, 24 cantilever arms, and 53 box beams. B ramp bridge curved box girder (3) Longitudinal: The B ramp bridge span is arranged as 35+40+4×28+3×28+30m. Each span is longitudinally divided into three sections: A, B, and C. The lengths of the 40m span are 13m, 14m, and 13m respectively; the lengths of the 35m span are 12m, 11m, and 12m respectively; the lengths of the 30m span are 9.5m, 11m, and 9.5m respectively; and the lengths of the 28m span are 9m, 10m, and 9m respectively. The entire bridge is divided into 60 steel main beams, 60 cantilever arms, and 108 box beams. The C ramp span is arranged as 4×30+3×30+30+45+30m. The 45m span is longitudinally divided into 5 sections: A, B, C, D, and E, with lengths of 8m, 8m, 13m, 8m, and 8m respectively. The 30m span is divided into 3 sections: A, B, and C, with lengths of 9.5m, 11m, and 9.5m respectively. The entire bridge is divided into 90 steel main beams, 60 cantilever arms, and 220 box beams.

3. The method for hoisting and constructing a curved lane steel box girder to change its center of gravity according to claim 1, characterized in that: In step 2, a pier-supported structure is adopted. The pier is first set up in the site. After the transport vehicle of the curved box girder (3) arrives, the curved box girder (3) is directly hoisted to the top of the pier for secondary assembly. The main structure of the pier is a φ219×10 steel pipe. 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. 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 800 mm. When the two-piece scaffold is erected on site, the ground sample line of the curved box girder (3) is first laid out according to the scaffold drawing, and 6 piers are arranged under each production section, and the piers are all located under the partition of the curved box girder (3).

4. The method for hoisting and constructing a curved lane steel box beam to change its center of gravity according to claim 1, characterized in that: In step 3, a crawler crane is used for lifting. After the arc box girder (3) is assembled on the roadbed, the entire span is lifted into place. Four lifting eyes are arranged. The maximum weight of the segment is 80 t. A safety factor of 1.2 is used. Considering that only three lifting eyes are subjected to force, the force on each lifting eye is F=80*1.2 / 3=33 t. Therefore, a 30-40 t lifting eye is selected. For a segment with a lifting weight of 60 t or less, the force on each lifting eye is F=60*1.2 / 3=24 t. Therefore, a 20-30 t lifting eye is 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.

5. The method for hoisting and constructing a curved lane steel box beam to change its center of gravity according to claim 1, characterized in that: The process of crawler crane on-site assembly in step 3 is: unloading and installation of the main machine → installation of crawler tracks → installation of tail counterweight → assembly of main boom → threading 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.

6. The method for hoisting and constructing a curved lane steel box beam to change its center of gravity according to claim 1, characterized in that: Step 3: During the hoisting of the curved box girder (3): Part 1: The first round of assembly of the curved box girder (3) includes assembling 1#, a total of 5 hoisting segments; the second round of assembly of the curved box girder (3) includes assembling 2#, a total of 5 hoisting segments; Part 2: The third round of assembly of the curved box girder (3) includes assembling 3#, 4#, and 5#, a total of 18 hoisting segments; the fourth round of assembly of the curved box girder (3) includes assembling 6#, 7#, and 8#, a total of 16 hoisting segments; Part 3: The fifth round of assembly of the curved box girder (3) includes assembling 9# and 10#, a total of 12 hoisting segments; The specific process of lifting is: Step 1: The crawler crane lifts the LA1 segment under the super-lift tower arm working condition. At this time, the crawler crane has a lifting radius of 34m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly lowers the beam; Step 2: The crawler crane lifts the RA1 segment. At this time, the crawler crane has a lifting radius of 34m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the girder and lifts the cross-connection between the boxes. Step 3: The crawler crane lifts the RC1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly lowers the beam. Step 4: The crawler crane lifts the LC1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the girder and lifts the cross-connection between the boxes. Step 5: The crawler crane lifts the RB1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly lowers the beam. Step 6: The crawler crane lifts the LB1 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the beam and lifts the cross-connection between the boxes. Step 7: The crawler crane lifts the C8A segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly lowers the beam. Step 8: The crawler crane lifts the C8B segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the girder and lifts the cross-connection between the boxes. Step 9: The crawler crane lifts the C8C segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the girder and lifts the cross-connection between the boxes. Step 10: The crawler crane lifts the RB8 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly lowers the beam. Step 11: The crawler crane lifts the LB8 segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the beam and lifts the cross-connection between the boxes. Step 12: The crawler crane lifts the C7A segment. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly lowers the beam. Step 13: The crawler crane lifts the C7B and C7C segments. At this time, the crawler crane has a lifting radius of 36m. After adjusting the position of the curved box girder (3), the girder is slowly lowered and the cross-connection between the boxes is lifted. Step 14: The crawler crane lifts the C6A and C6B segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), slowly drops the beam, and lifts the cross-connection between the boxes. Step 15: The crawler crane lifts the C6C and C6D segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), slowly drops the girder, and lifts the cross-connection between the boxes. Step 16: The crawler crane lifts the RB6 and LB6 segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), slowly drops the beam, and lifts the cross-connection between the boxes. Step 17: The crawler crane lifts the C5A and C5B segments. At this time, the crawler crane has a lifting radius of 32m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), slowly drops the girder, and lifts the cross-connection between the boxes. Step 18: The crawler crane lifts the C5C and C5D segments. At this time, the crawler crane has a lifting radius of 22m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), slowly drops the girder, and lifts the cross-connection between the boxes. Step 19: The crawler crane lifts the LB5 and RB5 segments. At this time, the crawler crane has a lifting radius of 22m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), slowly drops the beam, and lifts the cross-connection between the boxes. Step 20: The crawler crane lifts the LA4 and RA4 segments. At this time, the crawler crane has a lifting radius of 32 m. After the height of the curved box girder (3) reaches 62 m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the beam and lifts the cross-connection between the boxes. Step 21: The crawler crane lifts the LC4 and RC4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), slowly drops the girder, and lifts the cross-connection between the boxes. Step 22: The crawler crane lifts the LC4 and RC4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), slowly drops the girder, and lifts the cross-connection between the boxes. Step 23: The crawler crane lifts the LC4 and RC4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), slowly drops the girder, and lifts the cross-connection between the boxes. Step 24: The crawler crane lifts the LB4 and RB4 segments. At this time, the crawler crane has a lifting radius of 36m. After the height of the curved box girder (3) reaches 62m, the crawler crane rotates, adjusts the position of the curved box girder (3), slowly drops the beam, and lifts the cross-connection between the boxes. Step 25: The crawler crane lifts the LA4 and RA4 segments. At this time, the crawler crane has a lifting radius of 32 m. After the height of the curved box girder (3) reaches 62 m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the beam and lifts the cross-connection between the boxes. Step 26: The crawler crane lifts the LB2 and RB2 segments. At this time, the crawler crane has a lifting radius of 32 m. After the height of the curved box girder (3) reaches 62 m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the beam and lifts the cross-connection between the boxes. Step 27: The crawler crane lifts the LC2 and RC2 segments. At this time, the crawler crane has a lifting radius of 32 m. After the height of the curved box girder (3) reaches 62 m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the girder and lifts the cross-connection between the boxes. Step 28: The crawler crane lifts the LA2 and RA2 segments. At this time, the crawler crane has a lifting radius of 32 m. After the height of the curved box girder (3) reaches 62 m, the crawler crane rotates, adjusts the position of the curved box girder (3), and then slowly drops the beam and lifts the cross-connection between the boxes. Step 29: The crawler crane lifts the C9A, C9B, and C9C segments. At this time, the crawler crane has a lifting radius of 40m. After adjusting the position of the curved box girder (3), the beam is slowly lowered and the cross-connection between the boxes is lifted. Step 30: The crawler crane lifts the LB9 and RB9 segments. At this time, the crawler crane has a lifting radius of 40m. After adjusting the position of the curved box girder (3), the beam is slowly lowered and the cross-connection between the boxes is lifted. Step 31: The crawler crane lifts the C10A, C10B, and C10C segments. At this time, the crawler crane has a lifting radius of 38 m. After adjusting the position of the curved box beam (3), the beam is slowly lowered and the cross-connection between the boxes is lifted. Step 32: The crawler crane lifts the LB10 and RB10 segments. At this time, the crawler crane has a lifting radius of 26m. After adjusting the position of the curved box girder (3), the beam is slowly lowered and the cross-connection between the boxes is lifted.

7. The method for hoisting and constructing a curved lane steel box beam to change its center of gravity according to claim 1, characterized in that: In step 3, a center of gravity balancing device is arranged between the ends of two adjacent curved box girders (3), and the center of gravity balancing device includes two box girder end side plates (4) and a cross beam (6). The two box girder end side plates (4) are respectively arranged on adjacent sides of the two adjacent curved box girders (3), and the cross beam (6) and the two box girder end side plates (4) are detachably arranged. Box girder end side plate bolt holes (5) are arranged on the box girder end side plates (4), and the two ends of the cross beam (6) are respectively provided with cross beam first end bolt holes (7) and cross beam second end bolt holes (8), and the cross beam first end bolt holes (7) and cross beam second end bolt holes (8) are respectively fixed by threading with the box girder end side plate bolt holes (5) by setting bolts.

8. The method for hoisting and constructing a curved lane steel box beam to change its center of gravity according to claim 7, characterized in that: The center of gravity balancing device also includes a column (9). When the first curved box girder (3) is installed, one end of the center of gravity balancing device is arranged on the first curved box girder (3), the upper end of the column (9) is connected to the bottom of the other end of the center of gravity balancing device, and the bottom of the column (9) is arranged on the pier (1); Before hoisting, the cross beams (6) at both ends of the arc-shaped box beam (3) are connected to the arc-shaped box beam (3) by bolts to form a whole. A φ219×8 column (9) is placed under the cross beam (6) on the concrete cap beam in advance, so that after the arc-shaped box beam (3) is hoisted into place, the center of gravity of the arc-shaped 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-shaped box beam (3) is in place, the cross beam (6) and the column (9) are welded.

9. The method for hoisting and constructing a curved lane steel box beam to change its center of gravity according to claim 1, characterized in that: In step 4, the specific process of bolting the arc box girder (3) at the bridge position is as follows: the bolting at the bridge position includes bolting between segments of the arc box girder (3) and bolting between the cross beam and the arc box girder (3). 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, with the chamfered side of the washer facing 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.

Images