Installation, disassembly and safety supervision and management of tower crane? Tower crane (also known as tower crane) can be installed near construction projects because its boom and tower body are vertical, and its effective working range is better than other types of cranes. The working height of tower crane can reach 100 ~ 160 m, which is especially suitable for the construction of high-rise and super-high-rise buildings. In addition, it has been widely used in building construction because of its convenient operation and simple amplitude variation. However, due to uneven dismantling teams or other reasons, tower crane safety accidents occur from time to time. In view of many major accidents in the installation and disassembly of tower cranes in recent years, the author talks about the problems that should be paid attention to in the installation, disassembly, maintenance and safety management of tower cranes.

A, tower crane installation

Tower crane installation and removal must be in accordance with the instructions and relevant regulations, the preparation of special installation and removal safety construction organization design (construction plan), and seriously organize the implementation. We should focus on the following tasks:

1, preparation before installation

(1) Check whether the site is suitable for dismantling the tower crane, and pay special attention to the surrounding environment.

(2) Check whether the foundation meets the technical requirements of the tower crane.

(3) Configure a reasonable power supply, and check the position of the crane and common tools such as auxiliary slings, rigging and rope buckles.

(4) Be familiar with the installation instructions of tower crane.

2, set up a security alert area, by designated personnel for security monitoring.

3. Before installation, all the equipment should be counted according to the original factory number directory and piled up according to the classification of each specialty.

4. Check, maintain, clean and adjust before installation. The contents and requirements are as follows:

Answer? Check whether the steel structure is deformed, twisted, bent or broken, whether the welds are open or missing, and carry out flaw detection inspection on the welds of important stress parts.

b？ Check, clean and adjust all rotating machinery, add lubricating oil and grease, power on for trial operation, and measure whether the motor speed and power meet the requirements of nameplate.

c？ Check whether the components of the electrical part meet the requirements, whether the cable appearance is damaged and whether the resistance value meets the standards.

d？ Check, clean and adjust the hydraulic system, and replace the hydraulic oil as appropriate.

e？ Check whether the wire rope is deformed or broken.

f？ Remove and check each pulley, and add grease to make it rotate flexibly.

5. During installation, all components shall be connected in strict accordance with the number, and the connecting plate shall not be used in the wrong position. It is forbidden to cut and weld at will or enlarge the diameter of pin holes and bolts at will.

6. The tightening force of connecting bolts of each part shall be tightened to the specified value with a wrench.

7, levelness, verticality measurement all application instruments, it is forbidden to visual, and make records.

8. After the installation of tower crane, organize relevant personnel to conduct a comprehensive installation quality inspection of tower crane. The inspection sequence should be carried out item by item from the foundation, tower, legs and safety devices to prepare for the load test. The specific items and contents of inspection shall be carried out according to the load test indicators specified in this regulation.

9. After the load test, the brake of the tower crane should be readjusted for handover.

10, the whole process of tower crane from installation to load test, acceptance and handover, all kinds of inspection data should be sorted out by the technical director of disassembly team, and submitted to the safety section of the project department and the mechanical equipment section of the company for archiving.

Second, the demolition of tower crane

The disassembly method of tower crane is the same as the installation method, and the procedure is just the opposite. When the building is completed, the site is not spacious when it is installed, so we must not take it lightly.

1. The basic requirements for tower crane disassembly are the same as those for installation.

2. Gas cutting is strictly prohibited during disassembly.

3. The removed bolts, pins, connecting plates and scattered parts shall be packaged and preserved.

The operating room is sealed with iron sheet.

5. The rotating machinery shall be maintained, oiled and sealed.

6, exterior wall paint anticorrosion.

7. After the tower crane is dismantled, the part that is conditionally put into storage shall be kept in storage, and the part that is unconditionally put into storage shall be transported to the special line and piled up for shipment.

Three, tower crane disassembly safety supervision and management

1. The ground in the dismantling operation area shall be flat, and littering is not allowed. Access roads should be clear and keep a prescribed safe distance from overhead lines.

2. Dismantling scheme, personnel quality, tools, subgrade and track laying, etc. Comply with the requirements of this regulation.

3, the demolition team set up a full-time security officer, responsible for the safety supervision in the process of demolition.

4. Demolition personnel must abide by the safety management regulations of the construction site, wear safety helmets, fasten safety belts for aerial work, and weld temporary railings where there is no safety belt to take root.

5. When the components are assembled vertically and horizontally, it is forbidden to clean up the two mating surfaces by hand to prevent squeezing injury.

6. Electric tools used for disassembly should be equipped with leakage protectors, and the temporary power supply should be safe and reliable.

7, lifting command should have someone who's in charge, in strict accordance with the demolition plan, shall not be cable-stayed oblique crane without authorization, in order to prevent damage to the assembled parts.

8. Fixed ropes, skids and jacks used in disassembly and assembly shall be firm and reliable.

9. Before the whole machine is installed, after debugging the temporarily charged electrical equipment, the power supply should be cut off to avoid accidents caused by misoperation.

10. After installation, do a good job of inspection before load test. The key inspection items include: cleaning of temporary power supply, scaffolding, tie rods and steel bars, terminal travel of track, various safety protection devices, etc. See the relevant clauses in the load test measures of this regulation for specific inspection contents.

1 1, steel wire ropes and snap rings for lifting should be carefully checked before use, and those that do not meet the requirements are strictly prohibited.

12. The operator must designate a captain to be responsible for the safety management of the operation. During the commissioning of the newly installed tower crane, the captain or experienced driver shall be responsible for the operation.

13. During installation, it is forbidden to lack fasteners such as bolts, shaft pins and cotter pins; Lifting tools, such as blind pins, sliding bolts, discarded shackles, rolling heads, wire ropes and jacks, shall not be used.

14. During the lifting process of tower crane, the operation must be carried out according to the operating procedures.

15, jack-up or drop section, must pay attention to the jack-up brace and safety pin in place and contact surface.

16, the tower must be balanced when hoisting! No turning at will!

17. If there is a "click" sound in the process of jacking the top of the tower, stop the operation immediately, check carefully, find out the reason and eliminate the fault, and then decide whether to continue jacking according to the situation.

18, tower crane section, all fasteners must be tightened at any time, and the verticality correction is not greater than the allowable range specified by the manufacturer.

19. In case of severe weather such as strong wind, rainstorm, thunderstorm and fog, the installation and disassembly operations should be stopped.

20, tower crane installation, should carefully check the parts fastening is good, limit safety device is complete in good condition. It can only be delivered after the trial operation is qualified.

Four, tower crane repair and maintenance

The maintenance of mechanical equipment is a very important link to ensure its normal and safe operation. Many mechanical accidents have fully proved this point.

1, the main purpose of tower crane maintenance is to ensure the lubrication and anticorrosion of machinery by oiling and wiping, so as to reduce mechanical wear and prolong service life. On the other hand, through the maintenance of various components and structures, the hidden dangers of machinery can be found and eliminated in time, and the purpose of safe production can be achieved. Therefore, the crew is required to carefully maintain the electrical parts, mechanical parts, structural parts and safety devices of the machines according to the maintenance procedures of the machines they operate. Especially when checking dangerous parts such as boom, fasten your seat belt.

2. Location and requirements. The electrical part mainly includes whether the switches, controllers, motors and electrical components are clean and dust-free, whether the lines are well insulated and aging, and whether the connectors and contacts are loose. The mechanical part is mainly the technical conditions of various transmission mechanisms, pulley blocks, brakes, wire ropes, hooks and other parts. ?

Tower crane focuses on the following points:

(1) Whether there is rail gnawing, rail jumping and swinging when the traveling wheel is running.

(2) Whether the reducer has noise, fever, vibration on the frame or oil leakage.

(3) Whether the open gear has noise, inconsistent wear and cracks.

(4) Whether the concentricity deviation of the coupling is greater than 1㎜, or whether the transmission shaft swings and makes noise during operation.

(5) Whether the pulley groove is unevenly worn, and whether there is left-right movement and inclination.

(6) Whether the hoisting and luffing mechanism can ensure stable and accurate control, smooth start and braking.

(7) Whether there is a control fault or the brake shoe is hot and smoking when the brake works.

(8) Whether the steel wire rope is firmly fixed, and whether the wear and broken wires meet the specified scrapping standards.

(9) Whether the fatigue, crack and wear of the dangerous section of the hook meet the specified standards.

(10) Lubrication of pulleys, bearings, etc

Before each shift change, carefully check and test the safety devices and limit devices of all departments. It is not allowed to work with illness, to carry out maintenance during the operation and to overload the operation.

Five, tower crane common accident causes and prevention

Most of the accidents of tower cranes are caused by three violations (that is, illegal command, illegal operation and violation of labor discipline). The specific analysis is as follows:

1, lack of safety technical knowledge. Tower crane operators, namely drivers, signal commanders and hook workers. Professional safety technical training and education must be carried out. The driller must be familiar with the structure, principle, performance, operation method and use of tower crane slings, and pass the safety technical training and assessment, obtain the operation certificate of special operators and hold relevant certificates.

2. Tower crane capsizing and broken arm accidents are often mentioned, in training courses and safety education meetings before class, but they still happen frequently. What is the main reason?

(1) overload operation. There are generally two situations of overload. One is to blindly lift the lifting object with unknown weight, such as the lifting object is in a frozen and sticky state or buried in the soil; Second, the weight of the hoisted object is not accurately estimated. According to experience, it is almost the main reason for overload, so it is strictly stipulated in the operating rules that "overload is strictly prohibited".

(2) Wind power generation. The higher the tower crane, the greater the influence. When the wind blows, it is bound to be subjected to great wind pressure. The tower crane must have enough stability to resist the wind pressure overturning moment suddenly produced by the wind, so that the tower crane will not overturn.

(3) The influence of slope. No tower crane track can be absolutely horizontal, so the tower crane will tilt, and the degree of tilt depends on the size of the slope. If it's almost below, it will tilt a lot above. Obviously, tower crane inclines to reduce stability, which must be paid enough attention.

(4) Inertia force (also called dynamic load) of starting and stopping heavy objects. When the hoisting mechanism works, the suspended heavy objects suddenly brake, which will produce the inertia force of starting and stopping, form the dynamic load, and make the tower crane suffer the overturning moment, which must also be paid enough attention.

(5) inertial force. When the walking, slewing, luffing and other mechanisms are started or braked, the corresponding moving parts of the crane will produce inertial force, which often adversely affects the stability of the tower crane. Especially when the driver's operation is unstable, this influence will increase. This is the reason why the tower crane is often overloaded and overturned in operation.

(6) Rotating centrifugal force. When the crane rotates, the gravity of the rotating part of the crane will produce rotating centrifugal force. The rotating centrifugal force will cause the tower to be subjected to corresponding horizontal tension. The faster the rotation, the greater the tension, which will make the tower crane suffer from overturning moment. Although this influence is small, it cannot be ignored.

Of the above six aspects, load and wind have the greatest influence. We can't control the wind, so we must take corresponding measures to protect it. For example, it is stipulated that the operation must be stopped when the wind force is above 6, the boom should be relaxed after work to ensure that it can rotate with the wind, and all rail tongs should be fastened. The load must be strictly controlled, and overload operation is strictly prohibited. As long as this level is well controlled, tower crane accidents can be greatly reduced.

3. The safety device is imperfect or invalid. "Four Limits and Two Safety" of Tower Crane. In particular, the overload limit is imperfect or out of order. Ensuring that safety devices are complete, sensitive and effective is an important link to prevent accidents.

4, illegal (driver) open tower crane (driving without a license). Due to the lack of safety technical knowledge and unskilled operation, accidents are prone to occur. It is forbidden for non-drivers to drive tower cranes. Those who have passed the training and examination cannot operate independently, and the system of holding certificates is strictly implemented.

5. Accidents caused by tower crane operating in spite of illness also occur from time to time. No matter which part or mechanism of the tower crane, it is necessary to ensure flexible and reliable operation, especially the brakes of each part. In addition to regular inspection and maintenance, eliminate hidden dangers in time and prevent the tower crane from running in spite of illness, education and insurance should be carried out on time according to the maintenance and repair procedures, and drivers should clean, lubricate, adjust, reinforce and prevent corrosion of the machinery they operate.

6. Tilt crane. The stress state of the crane changes, and the horizontal tension generated by the inclined crane will greatly increase the overturning moment of the crane, causing accidents.

7, signal command error, drunken homework, etc. Is the cause of all kinds of accidents.

Six, tower crane safety management points

1, to further improve the safety management awareness of tower cranes. We must fully realize that tower crane is a special equipment. When installing and dismantling, you must apply to the technical supervision institution for installation and dismantling. For the purchased tower crane, be sure to check whether the manufacturer has the production license, product certificate and safety certificate of the production enterprise. At the same time, we should understand the relevant business knowledge of tower crane and fully understand the importance of tower crane management. Safety management of tower crane is an important part of construction safety management. It is necessary to realize the danger of special equipment and correctly understand that safety is the truth of benefit. It is necessary to establish a complete maintenance system for tower crane drivers, command posts and special equipment. It is necessary to blame people and implement various systems.

2, do a good job of safety supervision and inspection of tower crane. Safety performance testing of tower crane is an important part of safety management of tower crane. Whether safety supervision and inspection can be done well is directly related to the safe operation of tower crane. Special equipment supervision and inspection institutions should earnestly shoulder this heavy responsibility. In order to do a good job in inspection, we must also establish a special equipment safety inspection team with excellent technology and high quality, which requires our inspectors to establish a high sense of responsibility, study their business seriously, constantly improve their professional skills, strictly implement the supervision and inspection rules for hoisting machinery, do in-depth and meticulous work, find problems in time, help enterprises solve practical problems, and establish a sense of serving enterprises. Doing the above work well can ensure the safe operation of tower crane and play its due role in economic construction.

-preventive measures for common accidents in the use of tower cranes. Tower cranes are referred to as tower cranes and originated in Western Europe. A rotating crane with a movable arm installed at the upper part of the tower. The working space is large, which is mainly used for vertical and horizontal transportation of materials and installation of building components in building construction. It consists of metal structure, working mechanism and electrical system. The metal structure includes tower, suspender and base. The working mechanism has four parts: lifting, luffing, rotating and walking. Because the ratio of the height of tower crane to the distance between its supporting point is very large, it is very important to ensure its stability during disassembly and assembly. ?

China Paper Network/11/view-6377643.htm.

Over the years, there have been hundreds of tower crane accidents, which have caused different degrees of damage. The operation of tower crane not only does not conform to the regulations during installation and disassembly, but also causes safety accidents. It is also easy to cause dumping accidents during use. But after careful induction, it can be roughly divided into the following categories:?

(1) Due to the soft or uneven foundation, safety devices such as lifting limiter or moment limiter fail, resulting in the whole tower body dumping or the crane boom, balance arm and tower cap of tower crane falling to the ground. ?

(2) Over-torque lifting, over-winding due to the limitation failure of the boom, crane dumping and other reasons will all lead to broken arm accidents. In addition, when there are problems in manufacturing quality, long-term lack of maintenance, cracks in arm joints, overload, vibration caused by emergency braking, etc. Such accidents are also easy to happen. ?

(3) Weight loss accidents caused by heavy objects coming out of the hook mouth or special slings. For example, improper binding method of hanging objects, hook without anti-falling device, hook mouth deformation, anti-falling device failure and so on. Make heavy objects fall off. In addition, due to the manufacturing defects or fatigue cracks of the hook steel, when the load is too large or the brake is urgent, the hook breaks, resulting in a broken hook accident. ?

(4) The hanging rope or lifting rope breaks, resulting in weightlessness accident. Overloaded hoisting, failure of hoisting limit switch, inclined hoisting, and continuous use of wire rope beyond the scrapping standard are the main reasons for rope breakage. It can be seen from the above types of accidents that tower cranes often occur, once an accident occurs, it will be enough to cause the machine to be destroyed and people to die, resulting in huge losses. ?

Therefore, analyzing the causes of these accidents can help us prevent the recurrence of similar accidents and further promote the management of safety production. Tower crane belongs to boom crane, which is mostly used in industrial and civil construction sites. Because of its complex and changeable working environment, long boom, large working face, many connection points of standard sections and other structural members, high overall height, frequent replacement of operators and field managers, and low professional quality, tower crane accidents account for a high proportion in cranes, and tower crane overturning accidents have caused great losses to people and property. Therefore, it is necessary to carefully analyze the reasons and put forward corresponding solutions. ?

Accidents caused by illegal operation: tower crane accidents caused by overload use? When the rated lifting torque is exceeded, the torque limiter is damaged, removed, not adjusted or checked irregularly, which leads to the failure of the torque limiter and an accident. There are many such accidents, and the losses are also great. As we all know, the quality of tower crane drivers is uneven, and many drivers think that tower cranes have a certain safety factor, and overload has nothing to do with it. I don't know the safety factor of tower crane is set to adapt to different working conditions. Comments: Torque limiter is the most critical safety device of tower crane, which should be maintained, adjusted and checked regularly. Shall not be adjusted, damaged or removed without authorization. ?

Accidents caused by unqualified foundation: ① failure to carry out durability test according to the requirements of the manual; The tower crane capsized due to insufficient foundation bearing capacity. (2) The foundation is too small to meet the stability of the tower crane under various working conditions; (3) The self-made anchor bolt can't meet the requirements specified in the manual, and the tower crane capsizes due to the fracture of the anchor bolt; (4) The anchor bolt is welded with the foundation reinforcement. ?

Accidents caused by improper attachment of tower crane: ① No attachment device was installed when the tower crane exceeded the independent height; (2) The independent lifting height of the tower crane above the attachment point exceeds the requirements of the manual; (3) The attachment rod and the attachment distance are increased at will without calculation and design. ?

Does the fatigue of steel structure lead to the cracking of base metal in key parts or the cracking of key welds? There are many factors that cause fatigue cracks, which are related to design, manufacture and materials, but most of them are closely related to long-term overload use and are the result of gradual accumulation. This kind of accident can be completely avoided if it is checked regularly, found in time and handled in time. The parts prone to fatigue mainly include: the joint between the foundation section and the bottom beam, the welding seam at the main limb or connecting sleeve of the reinforced section or standard section above the diagonal brace, the variable section of the tower, the upper and lower supports, the rotating tower, the main limb or ear plate at the lower part of the tower top, etc. ? Comments: Accidents caused by fatigue of steel structures and welds are also many links. With the equipment used for many years, there are many accidents caused by fatigue, and many accidents are caused by the combination of fatigue and illegal operation. ?

Accident of pin shaft falling off: ① pin shaft jumping and shearing cotter pin lead to pin shaft falling off; ② No cotter pin is installed or replaced by iron wire during installation; (3) welding the pin shaft with the structure without installing a pressure plate or a cotter pin; (Due to the poor weldability of the pin shaft, it is easy to weld under vibration and impact, resulting in the pin shaft falling off); (4) The fastening bolt of the shaft end baffle falls off due to long-term vibration without spring pad or loose fastening, and the pressure plate does not work, resulting in the pin shaft falling off; ⑤ The triangular baffle at the joint of the boom is deformed or welded due to repeated disassembly, which causes the boom pin to fall off. ?

Accidents caused by broken wires of steel wire rope: ① Broken wires and strands of steel wire rope were not found and replaced in time; (2) The hook suddenly falls to the ground, and the pulley rope device of the hook, trolley, etc. is not firm or damaged, causing the wire rope to fall out of the groove, thus crushing the wire rope; (3) The height limit doesn't work, and the hook hits the car beam and breaks the wire rope. (4) Other safety devices are damaged, removed or fail to cause accidents, such as brakes, weight limiters, height limiters, rotation limiters, amplitude limiters and travel limiters. ⑤ Loose bolts of standard section In recent years, in the inspection of tower crane, it was found several times that the connecting bolts of standard section of tower body were loose. Some nuts can be screwed in by hand, and the axial movement of the bolts can be felt by gently lifting them by hand, indicating that the bolts have been loose to the point where there is no stress. The tower body is like the "trunk" of the tower crane, which supports the upper working parts and mainly bears the axial pressure, horizontal force, bending moment and torque from the top working parts. It is installed at the site according to the standard section through the jack-up device of the tower crane itself to achieve the required working height. It can be seen that it is very dangerous to fail to find or leave loose bolts of standard joints in time! ?

According to statistics, at present, the disassembly process of tower crane has become the link with the highest probability of major accidents, accounting for more than 60% of the national disassembly accidents. Strengthening the management of this link will play a positive role in curbing the major accidents of tower cranes. ?

(1) technical management. The demolition unit shall formulate the tower crane demolition construction scheme according to the construction site conditions and random technical documents. The demolition construction plan should at least include the following contents: ① Define the organization and management of operators, clarify their post responsibilities, and equip commanders, riggers, assemblers, electricians, professional dismantlers, safety supervisors and safety leaders; ② List the disassembly sequence table of main components; (3) Explain the operation steps from hoisting to positioning in detail; ④ Put forward specific requirements and measures for safety control points during disassembly; ⑤ Provide provisions for applicable weather conditions; ⑥ Clean up the warning zone of demolition operation and set warning signs. After the demolition plan is formulated, it shall be approved and implemented by the technical director of the demolition unit. For the construction site where demolition is difficult or requires special methods, relevant experts can be asked to formulate a more detailed text plan, which will be implemented after the demonstration. ?

(2) Operation control. Before demolition, the operators shall be provided with safety technical disclosure, including at least post responsibilities, safety control points, common safety problems encountered and measures taken. Demolition work should be under the unified command of special personnel, and must be carried out in strict accordance with the procedures stipulated in the demolition construction plan. Full preparations should be made before disassembly, and the technical status of the tower crane should be confirmed according to the accompanying technical documents. ?

In short, professional installation company installation, professional testing institutions testing, professional skilled operators operating, professional equipment management personnel operating in accordance with safety regulations, is the cornerstone and guarantee for the safe use of tower cranes.

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Emergency rescue plan for production safety accidents in tower crane installation and disassembly I. Accident report:

1, after the accident, the accident unit must report the brief situation of the accident to the superior in the fastest way. And report in writing within 24 hours.

2. Do not conceal, lie or interfere with the normal investigation after the accident.

3 migrant workers, temporary workers, contract workers death accidents, according to the formal staff reporting.

Second, the emergency rescue measures:

Emergency rescue shall be implemented in a territorial responsibility system and implemented as soon as possible.

1. In case of sudden major safety accidents, it shall be reported to this project immediately and rescue shall be organized with all efforts. The legal representative and technical director of the company must arrive at the scene to organize rescue work with personnel, materials and funds at the first time.

2. After receiving the report of the construction safety accident, the project office should immediately start the emergency rescue designated by the head office, and rush to the scene at the first time to organize rescue, and quickly report the safety to the local government and the superior construction administrative department.

3. After receiving the report of major production safety accidents and unexpected time on the construction site, the head office shall immediately report to the leading group, and immediately notify the comprehensive coordination group to start the emergency rescue system, quickly implement emergency rescue mobilization, organize relevant personnel to rush to the site, and organize rescue together with the local government and competent departments. And promptly report to the district government and the municipal and district construction bureaus.

Three, the scene rescue specific matters needing attention:

1. Please ask medical rescue personnel to bring relevant instruments and medicines to the scene, and prepare for rescue according to relevant hospitals.

2. Please ask the public security personnel and urban management personnel to maintain the public order at the scene, evacuate the onlookers, set up a warning line and determine the warning range.

3. Count the number of people

4. Determine the rescue plan, implement the safety measures and signs of rescuers, eliminate major dangers, organize rescue in an orderly manner, and supervise the relevant units to implement the rescue materials and funds for treating the wounded.

5. Clean up the site, count the site personnel and evacuate the site.

6. Summary and analysis. Relevant information is released to the public media by specialized personnel.

Fourth, the significance of emergency rescue:

The emergency rescue of major production safety accidents must adhere to the people-oriented principle, and always put the rescue and evacuation of personnel first. Rescue work should adopt a scientific attitude and be carried out under the condition of ensuring the safety of rescuers, and should not be reckless. Avoid causing new casualties.