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Analysis of tower crane installation and removal scheme in comprehensive office building construction?

Installation and removal scheme of tower crane in the construction of comprehensive office building

Section 1 Project Overview

The comprehensive office building of XX Airlines is located in the southeast of the overpass between Shennan Avenue and Guangzhou-Shenzhen Expressway in XX City. It is a frame-shear structure with two floors underground and 28 floors above ground. The total height of the building is115.8m, and the total construction area is 46,508.44m..

Tower crane installation and required equipment in the second quarter

1, tower crane center layout:

A QTZ 125B tower crane (produced by Shaoguan Xinyu Construction Machinery Factory) is set up in the construction of this project. The tower crane center is located in the east of Axis 2 1.4m and in the north of Axis D, 9.3 14m (see the tower crane location map for details). Because there is a high-voltage cable passing through the west side of the site, the forearm of the tower crane is only installed 50 meters.

2. Tower crane foundation

The natural whole house foundation is adopted, with a width of 5000× 5000m and a height of1.40 m. According to the geological report, the standard value of foundation bearing capacity is 230kpa, which meets the design requirements of the manufacturer. See the basic drawing below for details.

3. Install the required equipment:

(1)45t truck crane.

(2) 1 30-ton jack.

(3) 1 theodolite and level.

(4) 1 seismic station.

(5) 1 socket wrench.

4, installation requirements and order

According to the construction requirements, the tower crane needs to pass through two floors of the basement, and the tower crane foundation is located below the basement (see the basic drawing for details), that is, the elevation of the tower crane foundation surface (-9.350m) is consistent with that of the basement, and the floor to be constructed in the future can be covered on the tower crane foundation surface, and the tower crane foundation adopts C30S8 impervious concrete, and the concrete label is the basement. In order to speed up the construction progress, the tower crane foundation construction should be carried out first, and the tower crane installation can only be carried out after the concrete strength of the tower crane foundation reaches 80%. It is planned to be installed for the first time to a maximum free height of 37m. During installation, the steel bar standard section will be installed at the bottom of the tower, and then the tower crane and tower crane will be installed. The balance arm and boom will be assembled on the ground of the construction site for hoisting and assembly. The installation procedure is as follows: steel bar standard section → jacket → slewing support → tower crane → balance arm → power on → debugging → installation of support. After the whole machine is installed, the upper standard section will be installed. According to the design requirements, the first pitch of the attachment bracket is 30m from the ground, the first pitch is 25m from the ground and the third pitch is 20m from the ground. Thereafter, every time the tower rises 15m, an attached support shall be reinforced. When the attached bracket is fixed, the pagoda temple should be adjusted, and its vertical deviation should be no more than 1% and no more than 5cm. (Observe verticality with theodolite and level) Installation points and installation instructions provided by the manufacturer.

5. After the tower crane is installed and debugged normally, it should be carefully and comprehensively inspected again, and the power equipment department and security department of the company will organize the acceptance. After passing the test, it must be put into use.

In the third quarter tower crane installation

1, ready

Read the instructions carefully so as to set up the tower crane correctly and quickly, and reach the position where it can be jacked and added.

A 45-ton truck crane is needed to erect the tower. Arrange the tower crane installation personnel reasonably, properly coordinate and adjust various installation and assembly steps, the relationship between the passage and the assembly site, and minimize the time of using the truck crane.

2, the matters needing attention of the vertical tower

A, tower crane installation work must be carried out when the wind speed at the top of the tower crane is not more than 8m/s. ..

B, must follow the procedure of vertical tower.

C, pay attention to the choice of lifting point, according to the lifting parts to choose the appropriate length, reliable quality spreader.

D all detachable pins, connecting screws and nuts of tower crane components are special parts.

E, must install and use safety measures, such as escalators, platforms, square columns, etc.

F, must according to the length of the boom, correctly determine the number of counterweight, before installing the boom, you must first install a 2.32t counterweight on the balance arm, but it is strictly prohibited to exceed this number.

G, after installing the boom, it is forbidden to lift the boom before the balance arm is loaded with the specified balance weight.

H. The installation direction of standard package shall not be changed at will, otherwise it cannot be carried out.

First, the installation position of the tower crane on the construction site must ensure that the maximum rotating part of the tower crane, such as the boom and hook, is at a safe distance of 5M from the power line.

J prepare common tools such as auxiliary hoisting equipment, sleepers, rigging and rope buckles.

K refer to the attached drawings for the reference dimensions of the tower crane installation site.

L, before jack-up, drive the car to the specified jack-up balance position, turn the boom to the right side of the imported beam, and then lock the rotation of the tower crane with the rotary brake.

M, jack-up process, it is forbidden to turn the boom or start the car lifting hook.

N, standard section (or put down section), must be as close as possible to the tower.

3, power supply and debugging

After installing the whole machine according to the previous steps, check the verticality of the tower, and the tolerance is11000. Then, according to the requirements of the circuit diagram, turn on the power of all circuits and try to start all the mechanisms to run. Check whether the mechanisms are operating normally, and check whether the wire rope is in normal working condition. Whether there is friction with structural components, all abnormal conditions should be ruled out.

If the tower crane is to be used after installation, the safety device must be adjusted according to the requirements of relevant laws and regulations.

4, jack-up part

Preparation before jacking

1) Fill the oil tank according to the requirements of the hydraulic pump station.

2) Clean all standard sections, coat the joints of standard sections with butter, and arrange the standard sections to be hoisted in a row under the boom at the hoisting position, so that the tower crane does not need a slewing mechanism in the whole hoisting process, which can shorten the time spent in the hoisting process.

It should be emphasized that seven steel standard joints must be installed first, and then ordinary standard joints must be installed, and the order shall not be reversed.

3) The length of the cable is slightly longer than the total jacking height, and the cable is strengthened.

4) Rotate the boom to the front of the jack-up jacket, and the balance arm is behind the jacket (the jack-up oil torque is just below the balance).

5) Prepare the imported rollers on the imported platform, and prepare the high-strength bolts of the tower on the scaffold platform.

4.2 Balance before jacking of tower crane

1) Before balancing the tower crane, the trolley must be moved to the reference position, a standard section or its target weight shall be hoisted, and then the connecting bolts between the four legs of the lower bracket and the standard section shall be removed;

2) Rotate the joystick of the hydraulic jacking system to the jacking direction, so that the jacket is jacked to the position where the lower leg just leaves the main chord of the tower;

3) Check whether the tower crane is balanced by checking whether the lower leg is on a vertical line with the main chord of the tower, and observing whether the gaps between the eight guide wheels of the jacket and the main chord of the tower are basically the same. Slightly increase the fine adjustment position of the high-speed trolley until the balance is reached. So that that cent of gravity of the upper part of the tower crane fall on the position of the jacking oil cylinder beam.

4) You can tie a piece of cloth on the inclined web bar here to mark the balance position of the jib trolley, but it should be noted that the position of this mark changes with the length of the jib and should be removed in the future.

5) Operate the hydraulic system frame to descend and connect the connecting bolts between the lower bracket and the standard section of the tower.

4.3 jack-up part

Preparation before jack-up

1) Lift a section of steel bar standard section or ordinary standard section (collectively referred to as standard section) right above the introduction beam of jack-up jacket, install four introduction rollers at the lower end of the standard section, slowly lower the hook so that the introduction rollers installed on the standard section can properly fall on the introduction beam, and then remove the hook.

2) Move the car to the jack-up balance position.

3) Use the slewing brake on the slewing mechanism to brake the upper mechanism of the tower crane, and the slewing movement is not allowed.

4) Remove eight high-strength bolts connected to the bracket under the tower top.

Jack-up operation

1) Place the jack-up beam in the arc-shaped groove of the standard section steps (the pin at both ends of the jack-up beam must be observed to enter the arc-shaped groove), start the hydraulic system to make the piston rod extend, jack up the jack-up sleeve and its above parts, the jack-up sleeve is slightly higher than half of the height of the standard section, and put the climbing claw of the jack-up sleeve on the standard section step. After confirming that the two climbing claws are accurately hung on the top of the step, fully retract the piston of the oil cylinder, lift the jack-up beam, and push the jack-up beam on the previous step again on the standard section. Extend the oil cylinder again, and jack the upper structure of the tower crane slightly higher than the height of half a standard section. At this point, there is just enough space above the tower to load a standard section. Guide the standard section of jack-up sleeve into the beam directly above the tower, slightly retract the oil cylinder, drop the newly introduced standard section on the top of the tower, align it, remove the imported roller, and use 12 or 8 M36 high-strength bolts (two nuts are required for each high-strength bolt).

Retract the cylinder again, lower the bracket at the top of the new tower and align it. Connect the lower support with the tower firmly with eight M36 high-strength bolts, and each height bolt must have two nuts, which completes the work of adding a standard section. If you add several standard sections in succession, you can repeat the above steps several times. In order to make the lower bracket fall on the top of the tower smoothly, and

Quasi-connecting bolt hole. Before retracting the oil cylinder, four guide rods (one at each corner) can be inserted into the bolt holes at the four corners of the lower bracket from top to bottom to lower the lower bracket.

Matters needing attention in jack-up process:

A. When the wind speed at the top of the tower crane is greater than 8m/s, jack-up operation is not allowed.

B, in the process of jack-up, must ensure that the introduction of boom and standard section, and brake the boom by the brake of slewing mechanism, the car must stop at the specified jack-up balance position.

C, if you want to add several standard sections in a row, each additional section will be lifted by the tower crane itself. The main chord and lower support of the tower must have eight M36 bolts in a row. Only in this case can one nut be allowed for each of the eight bolts.

Steps on the added standard section must be aligned with the existing standard section.

E before the lower bearing is connected with the tower with M36 bolts, it is forbidden to swing the boom, luffing trolley and hoist.

F. In the process of jack-up, if the hydraulic jack-up system fails, immediately stop jack-up, place the lower branch at the top of the tower, connect the lower branch with the tower with eight M36 high-strength bolts, and then troubleshoot the hydraulic system.

G, tower crane joint to meet the requirements of the working height (but not more than the independent height), the boom should be rotated to different heights, check the fastening problem of tower crane joint and foundation anchor bolt (one of the main chords is located directly below the balance arm, and all the nuts of this chord are tightened from bottom to top, and the above joints are locked with double nuts).

5. Work before putting into use

The work before the tower crane is put into use is to ensure that the tower crane can operate correctly and run under safe conditions. These tasks are mainly: inspection of tower crane components and debugging of various safety devices.

5. 1 component inspection

In order to check the correctness of installation work and ensure safe operation, a series of trial operation and inspection work should be carried out for all components of tower crane.

A, check the fastening connection between parts;

B, check the installation of supporting platform and guardrail;

E, check the wire rope winding is correct, can't friction tower mechanism and structure;

F, check the cable traffic;

G, check the balance arm counterweight fixation;

H, check whether there are sundries on the platform to prevent the tower crane from falling and hurting people during operation;

I, check the lubrication surface and lubrication points.

5.2 Commissioning of safety devices

The safety devices of tower crane mainly include: travel limiter and load limiter. Travel limiter includes: lifting height limiter, rotation limiter and amplitude limiter. The load limiter includes:

Lifting moment limiter, lifting weight limiter. It also includes an anemometer.

5.3 Check items after installation

Check the contents of the project inspection

Check the fastening of the anchor bolts of the underframe;

Check that the transmission line is 5m away from the maximum rotating part of the tower crane;

Distance, and check the passage of temporary cables to prevent damage.

Connection and fastening of standard section bolts of tower.

Check the connection between jacket and lower bracket;

In the process of jack-up, check the bracket in contact with the standard section; Axis sum; Connection and whether it is flexible and reliable;

Check the fastening of walkways and handrails.

Check the bolt fastening of the upper and lower bearing chambers connected with the slewing bearing;

Check the passage of the cable (the cable should pass through the right side of the upper bracket and the steel rings at the upper and lower ends of the ladder); Check the connection with the cab;

It is forbidden to store flammable items such as lubricating oil and oil cotton yarn in the cab.

Check the installation of the derrick and balance arm at the top of the tower;

Check the installation of escalators, platforms and guardrails;

Ensure that the lifting wire rope is properly wound.

Check the correctness of the installation of connecting shafts, washers and cotter pins at all parts of the boom;

Check the installation and operation of luffing trolley and the fastening of manned suspension rail;

Check the winding and fastening of hoisting and luffing wire ropes.

Balance arm Check the fixing of the balance arm; Check the installation of balance arm guardrail and walkway to ensure that the walkway is free of sundries.

Check whether the automatic ratio changing device and rope breaking prevention device of the hook are safe and reliable;

Check the hook group for defects that affect the use; Check whether the specifications and models of hoisting and winding wire ropes meet the specified requirements;

Check the wear of wire rope.

Check the installation and operation of the organization;

Adjust the brake clearance of each mechanism properly;

Check the traction mechanism. When the trolley runs with minimum and maximum amplitude respectively, there should be at least three safety rings on the wire rope at the drum;

Check whether the rope end compression of each wire rope is loose.

Safety device to check the installation of boom and balance arm;

Check the installation of escalators, platforms and guardrails;

Ensure that the lifting wire rope is properly wound.

Lubrication Check the lubrication according to the instruction manual and perform the lubrication work.

5.4 After the tower crane is assembled, it shall be tested in turn (once every construction site is transferred).

1) no-load test

Each mechanism should not be operated several times, but the diaphragm should be operated three times in a comprehensive way, and there should be no abnormal phenomenon during operation, otherwise the fault should be eliminated in time.

2) Static overload test

After passing the no-load test, carry out the static load test.

According to different boom lengths and different hoisting mechanism schemes, carry out static overload of 15m and 50m or more, lift the corresponding hoisting weight off the ground by about 0.5m at the lowest safe speed, record the distance from the ground, and keep 10min. After unloading, check the quality of metal structure and weld, and check whether there is permanent deformation.

3) Dynamic overload test

At 50m, the lifting weight is 1.43t(50m arm is 1.98t, 44m arm is 2.64t), and each mechanism performs 8- 10 actions within the corresponding range. All mechanisms should be flexible and the brakes should be reliable. There is no abnormality in all parts of machinery and structure, and the connection is not loose or damaged.

6, pier requirements

According to the manufacturer's technical requirements, the tower crane in this project supports the wall once every seven floors, and * * * plans to support the wall four times. After heightening and jacking, piers must be installed before heightening.

Section 4 Operation Control

1. When the tower crane is suspended for a long time, the hook should be raised to the highest position, the trolley should be pulled to the nearest point, and the boom should be stopped in the downwind direction. In order to ensure the progress of the project and the safety of the tower crane, the tower crane driver must be on duty in the cab for 24 hours. Succession and successor personnel shall not leave the cab without face-to-face handover, and handover records shall be carefully made during handover.

2. All operators must strictly implement the "Ten Don't Hoist" rule:

First, the command signal is unknown and it is not allowed to hang;

B, oblique traction and oblique hanging are not allowed;

C, unknown weight or overload are not allowed to be lifted;

D, loose objects are not firmly bound or materials are not allowed to be lifted when loading;

E, hanging objects are not allowed to be hung;

F, buried objects are not allowed to hang;

G, mechanical safety device failure or are not allowed to be suspended in spite of illness;

H, the scene light dark can't see the lifting point are not allowed to be lifted;

I, the blade is in direct contact with the wire rope, and lifting is not allowed without protective measures;

J, more than six winds are not allowed to be hoisted;

4, tower crane and signal commanders must be equipped with walkie-talkies; The walkie-talkie is frequency locked uniformly, and the user has no right to adjust the frequency; It's special for the plane and can't be checked out.

5. Signal commanders should be relatively fixed with tower crane operators, and personnel should not be changed at will without special reasons; The commander shall not change his post without the consent of the person in charge, and the handover must be made face to face.

6. The command language used on site should be Mandarin. Command languages should be standardized to prevent command errors.

7. In the process of command, the response system between the signal commander and the tower crane driver should be strictly implemented, that is, when the signal commander issues an action command, he should first call the number of the tower crane to be commanded, and only after the tower crane driver responds can the signal commander issue an action command of the tower crane.

8. In the process of command, the signal commander is required to observe the hook and the hoisted object of the tower crane at all times. In the process of tower crane turning arm, the signal commander must also look around the working state of adjacent tower cranes and send out safety prompts. The language of safety tips is clear, short, complete and clear.

9. The rigger should grasp the center of gravity of the hoisted object, and bind the hoisted object according to the regulations, and the binding must be firm. In the case of a large span of the suspended object, it is necessary to ensure safety and reliability and put an end to the phenomenon of "falling flowers".

10, the rigger must conduct a comprehensive inspection and appraisal of the wire rope before, during and during the shift, and unqualified wire ropes are strictly prohibited.

1 1, strengthen the management of tower ceiling. For tower cranes that have no influence on adjacent units, the jacking height and jacking time of the tower body should be determined according to the actual needs of the units, and a written report must be made to the tower crane command center; The tower crane command center implements computer management, and all tower cranes must be jacked as scheduled according to the height and time determined by the tower crane command center, and shall not be advanced or delayed.

Section 5 Tower Crane Demolition

1. Precautions for disassembly

A before the tower crane is moved out of the construction site, the jacking mechanism should be maintained and put into trial operation, because the jacking mechanism has been stopped for a long time.

B, in the process of trial operation, should have a destination to check the reliability of the limiter and brake of slewing mechanism.

C before the standard section of the tower crane has been dismantled, but the lower support is not connected with the tower body by M36 high-strength bolts, it is forbidden to use the slewing mechanism, luffing mechanism and hoisting mechanism.

D, tower crane disassembly is heavy-duty continuous operation for the jack-up mechanism, so the main stress parts at the bottom of the jack-up mechanism should be checked frequently.

E. When the jack-up mechanism is working, all operators should concentrate on observing whether the relative positions of the relative moving parts are normal (such as between the roller and the main chord, between the jacket and the tower). If the jacket deviates from the tower when ascending, it should stop ascending and descend immediately.

F the wind speed should be lower than 8m/S during disassembly. As the tower crane is dismantled, the building has been completed and the working site is limited, attention should be paid to the working procedures, and the stacking position should not be sloppy, otherwise personal safety accidents will easily occur.

2. The specific procedures for dismantling the tower

Rotate the tower crane to the disassembly area to ensure that the area can be accessed and will not affect the disassembly operation.

The disassembly procedure is the reverse of the assembly procedure of the vertical tower. The provisions of this manual must be strictly implemented, and it is strictly forbidden to violate the operating procedures.

The concrete steps for dismantling the tower are as follows:

A, drop tower standard section (if there are any attachment devices, remove them accordingly);

B, remove the counterweight of the balance arm (leaving a counterweight of 2.32t);

C. dismantle the boom;

D, removing the balance arm;

E. remove the cab; (It can also be removed together with the rotating assembly. )

F, removing the top of the tower;

G. disassembling the rotating tower;

H, disassembling the rotating assembly;

Remove jacket and tower reinforcement.

2. 1 Remove the tower

Turn the boom to the introduction direction of the standard joint, so that the rotary brake is in the braking state and the trolley is in the specified balance position. Dismantle the standard section at the top of the tower, leaving the lower standard to save 2cm, that is, stop jacking. The jack-up standard section is pushed out along the inlet beam, and the oil cylinder is retracted and supported by the climbing claw. The jack-up beam descends to a lower step and then retracts. The lower support is connected with the standard section of the tower by bolts, and the standard section is hoisted to the ground by a trolley.

Note: After the dismantled standard section is pushed to the outer end of the inlet beam, when the movable climbing claw on the jack-up jacket crosses the main chord of the tower standard section, the movable climbing claw must be turned over manually, so that the jack-up jacket can fall to the top of the next standard section smoothly.

Repeat the above actions, and take out the standard section of the tower from the jacking section in turn.

2.3 Remove the balance arm counterweight.

Fix the trolley at the root of the boom and remove the counterweight with the help of the auxiliary crane.

Remove the connecting plate of the counterweight, and remove the counterweight in turn according to the reverse order of the equipment weight.

There is only one counterweight left.

2.3 Dismantle the boom Remove the lifting wire rope from the trolley and the boom, and carefully check the total length of the grounding wire rope at the same time.

A. remove the lifting point;

B, gently lift the boom, so as to relax the lever system and remove the connecting pin shaft;

C, put down the boom, with sleepers on the bearing.

2.4 Disassembly of Balance Arm

Lift the counterweight first, then lift the balance arm through the four installations on the balance arm, so that the tie rod of the balance arm is in a relaxed state, and remove the tie rod connecting pin. Then remove the connection between the balance arm and the rotating tower, and gently put the balance arm aside.

2.5 remove the cab

2.6 Remove the top of the tower

Before disassembly, check whether there is cable connection with adjacent components.

2.7 Remove the rotating tower.

2.8 Remove the rotating assembly.

Hang the jacket, remove the connecting bolts between the jacket and the lower leg, support it on the tower with climbing claws, and lift and unload the rotating assembly with slings.

2.9 Remove the jacket and tower reinforcement.

A, lift the scaffold, slowly lift it out along the main chord of the standard section and put it on the ground;

B, in turn, hang down the standard section.

3. Matters needing attention after tower crane disassembly

3. 1 The tower crane shall be disassembled and inspected by engineers and technicians and professional maintenance personnel.

3.2 Check metal fatigue, weld crack and structural deformation. Structural components that are mainly stressed, and check whether the components of tower crane are damaged or scratched.

3.3 After inspection, defects and hidden dangers shall be repaired, and then rust prevention and painting shall be carried out.

Section 6 Tower Demolition Management

Most tower cranes in engineering construction can be removed and transported out of the site by conventional methods, but the method and sequence of subsequent removal should be considered before installing tower cranes. Dismantle the tower crane of building 9 (short tower) first, and then dismantle the tower crane of building 8.

Section 7 Safety Technical Measures

1, tower foundation installation must be carried out during the day, in strict accordance with the [installation instructions.

2, before the installation work, construction work must be carried out by a professional type of work, safety technology education for relevant personnel, do everyone know fairly well.

3, to participate in the installation work personnel must wear safety helmet, fasten your seat belt, and wear soft-soled non-slip shoes for homework.

4, the construction site need specialist command, coordinate with each other, to ensure safety.

5, to participate in aerial work personnel should strictly abide by the safety technical regulations of aerial work, all work tools should be fixed in a certain position with soft rope, to prevent accidents in the construction.

6. It is forbidden to throw tools, materials and other objects up and down to avoid injury accidents.

7. Carefully check whether the wire rope sleeve and snap ring for hoisting are reliable, and update them in time in strict accordance with the update standard.

8, carefully check all kinds of connecting bolt pin shaft, found that the damage or fatigue crack update in time.

9. The joints of all parts of the hydraulic jacking system are fastened, and the screws are fastened firmly.

10, check whether the insulation performance of cables and wires is good, whether the motor wiring is correct, and the action of each travel switch should be sensitive and reliable.

1 1, the iron tower and all electrical boxes are well grounded and connected to zero, and they are supervised by special personnel.

12. Safety signs should be set up when setting the security cordon on site, and all irrelevant personnel are prohibited from entering the operation area to avoid safety accidents.

13, attached, tower crane use should pay attention to the following points:

Climbing should be stopped if the wind is above level one or four. If you suddenly encounter strong wind during climbing, you must stop the operation and tighten the screws of the tower.

B, in the process of climbing, it is forbidden to turn, must follow the steps specified in the manual, pay attention to brace and pin in place, and the lifting part of tower crane must have full-time safety supervision.

C, the form and location of accessories, must be carried out according to the construction organization design. The vertical deviation should be corrected within one thousandth.

D, each attachment, must be in accordance with the provisions, after the acceptance can be put into construction.

14, tower crane operator safety responsibility system

First, study hard, strictly implement safety technology operating rules, and abide by safety production rules and regulations.

B, take an active part in safety activities, conscientiously implement safety disclosure, do not violate the rules, and obey the guidance of security personnel.

C, actively put forward opinions on unsafe operations, and have the right to refuse illegal instructions.

D, the operator must have participated in the study and training organized by the relevant departments, and can only operate after passing the examination and obtaining the working license.

E, before going to work, you must have a comprehensive understanding of the surrounding environment, forming the weight and distribution of lines, overhead lines, buildings and components.

F, the operator should make a sound signal before lifting, lifting and lifting the hook.

G, crane operators and commanders must cooperate closely, commanders must be familiar with the performance of the crane command. Operators should strictly carry out the signals of commanders. If the signal is unclear or wrong, the operator may refuse to perform. If the accident is caused by a command error, the commander is responsible.

H, tower crane before operation, should check whether there are people stay under the lifting objects or through, and it is forbidden to use tower crane to lift personnel, otherwise, will be punished according to the relevant reward and punishment system.

I, tower crane machinery must be operated in accordance with the provisions of the lifting performance, shall not be overloaded and lifting objects of unknown weight, for special circumstances need to overload must have technical measures to ensure safety.

Only with the approval of enterprise technicians and on-site supervision can the ownership be lifted.

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