Special Plan for the Installation and Dismantling of Tower cranes

Special Plan for the Installation and Dismantling of Tower cranes

I. Project Overview

Ii. On-site Arrangement

A total of tower crane platforms are set up in this project, respectively located at. For specific Settings, please refer to the general layout plan.

Iii. Basic Performance of Tower Cranes

Model

Lifting height

Lifting capacity

Boom amplitude

Rated lifting moment

QTZ40

Independent

29.7 m

Maximum lifting capacity

4t

"Maximum

48m

400kN·m

Attachment

90m

At the maximum extent

0.71 t

Minimum

2.5 m

Iv. Allocation of Resources for Tower Crane Installation and Dismantling

(1) Basic installation

Assemble the underframe, fix it at the embedded bolts, and use a level to check the levelness of the chassis.

2. Hoist the second standard section onto the base frame and fix it in place. The side of the standard section with steps should be at the bottom and should be perpendicular to the building.

3. Install the second standard section onto the first standard section, and make sure the steps are aligned up and down.

4. Assemble the frame. The surface with the oil cylinder on the frame should be aligned with the surface of the step on the standard section, and the climbing claws on the frame should be placed on the bottom step of the foundation section.

5. Assemble the upper and lower supports, slewing mechanism, slewing bearing, platform, etc. into one unit, and then install it as a whole on the frame and connect it firmly.

6. Install the tower cap and connect it to the upper support with a pin shaft. Note that the inclined surface of the tower cap should be on the same side as the boom.

7. Hoist the balance arm and connect it to the upper support with a pin shaft. Place a 2-ton counterweight at the third position from the tail of the balance.

8. Hoist the driver's cab and connect the power supply.

9. After assembling the boom, trolley, hoist basket and connecting the boom pull rods on the ground, they should be fixed on the brackets of the upper chord rods of the boom.

10. Use a truck crane to lift the entire boom smoothly into position and connect it to the upper support with a pin shaft.

11. Wind the hoisting steel wire rope, connect the short and long tie rods to the top of the tower cap, loosen the hoisting mechanism steel wire rope, slowly lower the boom to keep the tie rods in a tense state, and release the hoisting steel wire rope on the pulley block.

12. Install the counterweights, with 6 pieces of 2t each arranged in sequence.

13. Tension the steel wire rope of the luffing trolley.

(2) Standard section installation (tower upgrade)

1. The tower crane boom should be turned to the direction of introducing the standard section of the tower body (i.e., the positive direction of introducing the crossbeam).

2. Adjust the gap between the guide wheel of the climbing frame and the column of the tower body to be 3 to 5 mm. After the standard section is placed on the introduction trolley installed at the lower part of the upper and lower supports, use the hook to lift another standard section to a higher position and move the trolley (the trolley is approximately 10 meters away from the rotation center). The specific position can be determined according to the balance condition. Place the center of gravity of the upper part of the tower crane frame at the hinge point of the jacking cylinder, and then remove the 8 high-strength connecting bolts connecting the upper and lower supports to the standard section.

(3) Lift the tower crane frame so that there is just enough space above the tower body to accommodate one standard section.

(4) Pull the introduction trolley, lead the standard section to the upper part of the tower body, align it with the connecting bolt holes, retract the oil cylinder to press it tightly against the lower standard section, and then connect it with bolts.

(5) The above is a one-time jacking and section addition process. When continuous section addition is required, the above process can be repeated. However, after installing the three standard sections, the four lower reinforcing diagonal braces must be installed and adjusted to ensure that the four braces are evenly stressed before the tower lifting and hoisting can continue.

(6) During the process of adding sections, if the crane boom rotates severely, the bolts between the lower support of the tower crane and the standard section should be connected but not tightened. In case of any abnormal situation, the jacking should be stopped immediately.

(3) Debugging

After the tower lifting is completed, the height limit of the tower crane trolley, the height limit of the hook, the moment limit, the lifting limit and the rotation limit should be well controlled to ensure that each limit is sensitive and reliable. The specific debugging shall be handled by the electrician.

(4) Grounding devices and Requirements

It is required to weld galvanized flat iron to the main reinforcement of the tower base and lead out one flat iron to the bearing platform. The model of the flat iron is 60×5. The resistance of the grounding lightning arrester must not exceed 4Ω.

Vi. Operation and Maintenance of Tower Cranes

Operators must be certified and familiar with the maintenance and safety operation procedures of the machinery. Unauthorized personnel are not allowed to climb the tower crane without permission.

The normal operating temperature of the tower crane is -20 to +40℃, and the network speed is less than 13m/s.

3. All tower cranes must undergo no-load, static load and dynamic load tests during relocation, installation and use. The static load test lifting capacity is 125% of the rated load, and the dynamic load test lifting capacity is 110% of the rated load.

4. When expressing gratitude for work, in addition to the lighting provided by the tower crane itself, the construction site should be equipped with sufficient lighting facilities.

5. The operation of tower cranes must follow the "three fixed" system, and the driver's operation must be strictly carried out in accordance with the tower crane operation procedures. When dealing with electrical faults, there must be at least two maintenance personnel.

6. When the tower crane is working on site, the driver should be highly concentrated to avoid colliding with surrounding buildings.

7. Tower cranes should be frequently inspected, maintained and serviced. Sufficient lubricating oil should be provided for the transmission components. Vulnerable parts should be repaired or replaced in a timely manner. For connecting bolts, especially those that vibrate frequently, it is necessary to check if they are loose. If any are found loose, they must be tightened promptly.

8. Check and adjust the gap between the brake shoes and the brake wheel to ensure sensitive and reliable braking. The gap should be between 0.5 and 1mm, and there should be no oil stains or other dirt on the friction surface.

9. The maintenance and upkeep of steel wire ropes must be strictly carried out in accordance with the provisions of GB5144. If any exceed the relevant regulations, they must be replaced immediately.

10. Any damage, deformation, loosening, rust or cracks on the structures, welds and related components of the tower crane should be repaired in a timely manner.

11. All electrical circuits should also be inspected regularly. If there is any aging, malfunction or damage, they should be repaired and maintained in a timely manner.

Vii. Tower Crane Monitoring and Calibration

1. The settlement observation of the tower crane foundation should be carried out regularly, once every half month. The verticality measurement should be conducted once every half month when the tower crane is within the independent height. After the wall attachment is installed, it should be observed once a month (the verticality condition should be observed when the wall attachment is installed to facilitate the adjustment of the wall attachment).

2. When the tower crane shows uneven settlement and the verticality deviation exceeds 1/1000 of the tower height, the tower crane should be corrected. Before the wall attachment is set up, steel plates should be added between the lowest section and the tower crane's base bolts for correction. During the correction process, the tower body should be lifted with a high-ton jack. To ensure safety, the tower body should be tightly tied on all four sides with large cables, and the base bolts must not be removed. Only the nuts on the bolts can be loosened, and the specific length is determined according to the thickness of the added gasket. When multiple wall attachments are erected, the verticality correction of the tower crane can be achieved by adjusting the length of the wall attachment tie rods under the premise of ensuring safety.

Viii. Disassembly of Tower Cranes

The disassembly method of tower cranes is basically the same as the installation method, but the working procedure is opposite to that during installation, that is, those installed later are disassembled first, and those installed earlier are disassembled later. The specific steps are as follows:

It is advisable to adjust the gap between the guide wheel of the climbing frame and the column of the tower body to 3-5mm. Lift one standard section of the moving trolley to a position approximately 10m away from the center of the tower crane, so that the center of gravity of the tower crane falls on the hinge point of the top lifting cylinder. Then, remove the 8 high-strength bolts connecting the support and the tower body.

2. Fully extend the piston rod. When the jacking crossbeam is hung on the next step of the tower body, remove the connecting bolts between the tower and the tower body. Slightly raise the piston rod to separate the upper and lower supports from the tower body. Push out the standard section to the outer end of the introduction crossbeam. Then, when retracting all the pistons, place the climbing claws on the steps of the tower body, retract all the pistons, connect the upper and lower supports to the tower body, and insert the bolts.

3. The above is one process of lowering the tower body. When lowering the tower continuously, repeat the above process.

4. When demolishing, the principle of lowering first and then removing the attached wall must be followed.

5. When the tower crane is lowered to the ground (basic height), use a truck crane to assist in the removal: Lift the counterweight away (leaving two counterweights, that is, the third position of the balance arm from the tail)→ Remove the lifting arm (as a whole) to the ground → Lift the last counterweight away → Remove the balance arm → Remove the tower cap → Remove the upper and lower supports (including the power supply and the driver's cab)→ Remove the inclined struts of the climbing sleeve → Remove the last three standard sections.

Ix. Installation and Removal of wall-attaching devices

Before lifting the tower, the principle of installing first and then lifting must be strictly followed. That is, install the wall attachment device first and then carry out the tower lifting operation. When the free height exceeds the specified height, install the wall attachment device first and then lift the tower.

2. When dismantling the descending tower, the principle of descending first and then dismantling must also be strictly followed. That is, the climbing sleeve can only be removed when it reaches the attachment wall and the tower body can no longer be dismantled. It is strictly prohibited to dismantle the attachment wall first and then descending the tower.

X. Safety Measures

Before starting work, provide safety education to personnel, ensure they wear safety helmets properly, and strictly prohibit operation after drinking alcohol.

2. When installing or dismantling tower cranes, operations must be strictly prohibited when the wind force exceeds level 6 or during rainy or snowy days.

3. Operators should wear necessary safety devices to ensure safe production.

4. Obey unified command and prohibit throwing objects from heights.

5. Pay attention to the surrounding environment, such as high-voltage lines and ground load-bearing capacity, to ensure the safety of disassembly and assembly.

6. Special personnel should be on guard during the installation and dismantling of tower cranes, and unauthorized personnel are strictly prohibited from passing through the operation area.

7. The entire process of disassembling and assembling the tower crane must be carried out strictly in accordance with the operating procedures and construction plans. Any violation of regulations is strictly prohibited.