With the gradual development of construction projects towards the direction of short-term construction, the demolition of tower cranes in construction is becoming more and more frequent, and assembly and disassembly have become a very important work link. Based on ten years of work experience, the author discusses several issues that should be paid attention to during the demolition of tower cranes, so as to improve together.

　　1 Installation site selection

　　Under the premise that the tower model has been selected, the installation site selection should handle the following items: ① one-time installation can complete the overall project construction, avoid secondary displacement; ② avoid dead corners on the construction plane; ③ fixed attachment points It is convenient to choose and install; ④ the tower crane is easily disassembled and transported during construction; ⑤ avoid its sub-buildings, high-voltage power grids, etc. in the construction space; ⑥ help to install other equipment and lift building components according to construction needs.

　　2 Personnel organization

　　Tower crane assembly and disassembly is an important, dangerous, and intensive three-dimensional operation project, which must be highly valued from the ideology and fully guaranteed from the organization. In addition to the necessary construction management and professional technical personnel, all construction workers should undergo professional education, have the corresponding work safety knowledge, operation skills, and hold a certificate to work. Tower crane assembly and disassembly should be carried out by a professional construction team.

　　3 Discuss the demolition of construction equipment and equipment preparation

　　3.1 Issues to be noted

　　The migration of tower cranes generally involves disassembly, transportation, installation and other links. The equipment and machinery must be carefully organized and arranged to ensure safety and improve efficiency and economic benefits. It should be noted that: ① all lifting installation equipment should not only be used for large materials, but also not allowed to use overload capacity; ② transportation equipment should be arranged according to the quality and shape of each part of the tower crane, and try to avoid super long, super high, super wide, and heavy transport ; ③ Try to use the construction method of disassembling, loading and transporting, and installing at the same time to avoid secondary backhaul or occupying the undesirable construction site; ④ The site should be equipped with workers or ambulances, and high-altitude operations must be equipped with necessary communication tools Favorable for safe operation and normal construction.

　　3.2 Selection of lifting slings

　　Tower crane assembly and disassembly should generally be equipped with white hemp rope or nylon rope, various specifications of steel wire rope sleeves, steel cables, a certain number of 8# iron wires and special tools. These tools have sufficient allowable tensile force and safety factor. Different performance spreaders and rigging must be used and scrapped according to the corresponding standards.

　　3.3 Inventory and preparation of equipment parts

　　Phenomenon such as missing parts and few parts influencing the progress in construction are not uncommon. In order to ensure the construction progress, the above parts should be strengthened, managed, inspected and repaired; small parts and spare parts for equipment; special, general bolts, mother, pad; various specifications and Number of coupling pins and shafts; special tools for equipment assembly and disassembly; trimming tools for damage and deformation of some structural parts; wire rope clamps, rope loops, etc.

　　4 Tower crane foundation

　　Before installing the tower crane, you must ensure that it has a correct and intact foundation. The foundation of the tower crane is two types: fixed base and track walking. The following issues should be noted.

　　1) The foundation ground bearing capacity is the foundation foundation, and the necessary measures should be taken to ensure that the ground bearing capacity is 10-20t/m2. It can be constructed by tamping or compacting with 3:7 lime soil. Never use backfill soil and garbage without directly treating it as a base or rail.

　　2) The fixed base should be constructed according to the design requirements, to ensure that the size of each part, especially the embedded bolts, etc., must meet the size requirements from the foundation center to the building for building construction and attachment installation.

　　3) The track foundation should be constructed according to the design requirements, to ensure the technical requirements of the thickness of the gravel, the width of the subgrade, the spacing of the sleepers, the type of rails, rail joints, connecting rods, car stops, grounding, etc.

　　4) Under the foundation of the tower crane, there should be no hidden trenches, shelters, etc., and necessary drainage facilities should be provided.

　　5) Tower cranes should be installed on the ground, and the distance between the tower crane and the side of the foundation pit should be ensured during the construction of underground projects.

　　5 Tower crane installation and disassembly

　　5.1 Preparation before assembly and disassembly

　　The assembly and disassembly of the tower crane is the central part of the construction, which is very dangerous and must be fully prepared before construction: ① The technician should make a construction plan or construction organization design according to the installation and use instructions and the specific characteristics of the construction, and have a safe technical explanation Content. The construction plan must be communicated to all construction personnel before the operation, and must not walk through the site; ②The construction plan should make detailed calculations and discussions on the assembly and disassembly methods of the key and difficult parts, have a clear construction method, and select the correct equipment, slings, and lifting points , Bundling methods, etc.

　　5.2 Assembly and disassembly

　　The flag worker process must achieve unified thinking, unified command, and construction in accordance with the relevant safe operation procedures. It should be noted that: ① The legs of the lifting equipment for construction should be hit on the solid ground, and the necessary wooden planks or square beams should be cushioned; ② Select the appropriate lifting point position and auxiliary traction for diagonal, side, and lifting; ③ 2m The above-mentioned high-altitude operations must have safety protection. The operation should be stopped when the rain and the wind force are greater than level 5. The tower crane must be installed in a safe state when the wind and rain are encountered during construction; ④The boom must not be turned during lifting operations, and special personnel protection is set; ⑤ Assembly and disassembly must be carried out in strict accordance with the order required by the construction plan. No weight should be added to the front edge of the installation boom, and no heavy objects can be lifted without assembly. When disassembling, the counterweight should be disassembled before the boom is removed; ⑥Check whether the connecting parts of the tower crane are complete, reliable and effective, and whether the crane and rigging are safe.

　　5.3 Selection of lifting point

　　The selection of crane points and the method of assembly and disassembly in the assembly and disassembly of tower cranes are important links to ensure safe construction. Several issues should be noted.

　　① The lifting points of each component should use fixed positions or special hanging points as much as possible, and can be designed and configured by yourself if necessary. The reasonable inclination angle should be ensured when hanging sideways and diagonally. When there are inner and outer casing structural parts, the hanging point should be selected on the inner casing structure to avoid the separation between the inside and outside, such as the TQ60/80 tower crane spire. ②The components such as boom and balance arm should be as horizontal and directional as possible after lifting. The installation of the longer boom should use the method of non-horizontal lifting in the length direction, that is, the hinged end of the arm should be arranged higher than the head end of the arm. Then, install the boom to a horizontal position, such as 50m boom for FO/23B tower crane. ③ The crane boom of the tower crane is hinged into two parts, the front and rear parts are hinged together, and the lifting point should be as horizontal as possible when installing and disassembling, and the temporary connection rope is less stressed. ④ Disassembly is the reverse operation of installation, which is more dangerous. It should be operated in strict accordance with the order in the assembly and disassembly instructions of the construction plan, and the order must not be reversed. ⑤ Try not to use hooks and ropes to lift heavy objects.

　　6 Inspection and debugging of tower crane

　　Inspection and debugging is the last process of tower crane installation and construction, and also the last gate before using the tower surface. Therefore, inspection and debugging are also very important tasks. It should be noted that: ① The inspection of each part of the whole machine must be complete and meticulous, and the problems are solved in a timely manner; ② The maintenance work of each part should be done at the same time during the inspection and commissioning; ③ The working mechanism of the tower crane should be running normally, and the safety protection devices should be complete Effective; ④ The inspection and commissioning of the whole machine should be recorded to prepare for the acceptance of the tower crane.

　　7 Development of management system

　　The installation and disassembly of the tower crane is a very systematic management construction project. Based on years of experience and lessons, our unit has formulated a set of relatively complete system management measures, which are fully guaranteed from the organization and system. Formulate more detailed regulations for all aspects of construction management, such as tower crane basic acceptance regulations and technical files, installation and disassembly tasks, installation and disassembly safety technical disclosure, track acceptance records, assembly and disassembly construction records, assembly and disassembly completed inspection records, parts Counting records, using security technology to clarify, etc., practice has proved to be effective.