Demolition scheme of Panzhihua tower crane

I. Overview of tower crane performance

In this project, the standard boom of tower crane with arm length of 50M is selected; Tower standard section 2.0× 2.0× 3.0; Maximum lifting capacity10t, maximum lifting capacity 2.3t, lifting distance1150kn.m; Balance arm length 1 1.88M, counterweight 5, counterweight 4 3. 1 ton, 1 3.7 ton, * * * weight 16. 10 ton; Its free height can reach 50 meters and its first installation height is 35 meters. The maximum height of 0.000 in this project is 46M, and the basement is 8 floors. M, ***54 M, the spire is 7.2m, and the installation height of the whole machine is about 70M. Power 85KVA, 380V, 50HZ, equipped with force limiter, weight limiter, amplitude limiter and various signal devices. The machine is installed in the site of Building 32 of Shen Dong Water Affairs Bureau, with an area of 8856.76M2, which can basically meet the material transportation requirements of this project.

The balance arm of this tower crane is 4.8 1t, the walking platform is 2.3t, the boom * *13.87t, the tower head weighs 4.05t, and the first section of the tower body weighs 8.325t: the dead weight of this tower crane gmax = 192t, gmin = 68t, and the maximum load bending moment mmax = 25t. No-load maximum bending moment Mmax=4646.86KN.M, and maximum no-load pressure pmax =1915.94kn. ..

Second, the installation personnel organization

Installation director: XXX

Person in charge of tower crane installation and construction: XXX

Technical person in charge of installation and construction: XXX

Person in charge of installation and construction safety: XXX

Personnel involved in tower crane installation: XXX

Thirdly, the machine is equipped with

Equipped with the following instruments, machines and tools and labor protection articles:

1 50 ton crane

2. Theodolite 2

3.2 adjustable wrenches 12 "and 4 adjustable wrenches 18".

4. A multimeter.

5. Megger

6, grounding shaking table

7, a set of screwdriver

8, all kinds of rigging

9. Each person has a helmet, 30 pairs of safety belts and gloves, and 2 tool kits.

10, 2 ton hand pulley.

1 1, big hammer and small hammer: olive punch.

12, 30M/ brown rope/root: 2 pieces.

Four, tower crane installation procedures and requirements

1, base:

The foundation of fixed tower crane is a necessary condition to ensure the safe use of tower crane. The foundation of this machine is constructed in strict accordance with the instructions in the basic part of the manual.

The tower crane foundation of this project is planned to adopt natural foundation, with the top elevation of-1 1.000, silty clay layer, bearing capacity of foundation 180KN/M2, and slope coefficient of tower crane foundation pit 1:0.25.

Two sides of the tower crane foundation pit near the slope are built with 240-thick MU 10 and M7.5 cement mortar red brick retaining walls, and the other two sides are built with 1/2 thick MU 10 and M7.5 cement mortar red brick retaining walls; Apply 20 thick 1:2 cement mortar on all surfaces.

The tower crane foundation of this project adopts reinforced concrete independent column foundation, the foundation center is set between ⑤ ~ ⑦ axis and m ~ n axis, and the top elevation of the foundation is -9.400, which is buried under the platform. The specification is (8.0 ~ 9.5) × 8.0× 1.5 thick (trapezoidal plane), and four piles are embedded below. See the attached figure, C25 concrete (see the arrangement of φ25 @ 120 bidirectional reinforcement below, with φ20 @ 400 in the middle (9010d hook at each end), and the reinforcement is distributed in two directions along the length and width direction to bind the upper and lower reinforcement;

The foundation concrete is poured in two layers, the first layer is 800 thick and the upper layer is 700 thick. After the fixing feet are installed and corrected, the foundation surface is poured again after the steel bars are bound. The construction sequence is: tower foundation setting-→ earthwork excavation of tower foundation pit -→ 100 thick C 10 plain concrete cushion, foundation pit retaining wall-use a level to measure the elevation lines around the pit wall (level piles are driven at 800 height and 1500 height)-use a level to level and compact. Welded firmly with steel backing plate) → Reinforcement binding on foundation surface → Pouring 700-thick concrete on foundation surface (second floor) 【 Observe whether the fixed leg deviates from two mutually perpendicular directions with two theodolite 】 → Pay attention to maintenance.

The tower will pass through the second floor underground at an elevation of -8.3, and four ground beams will be prepared, including ⑦ axis JL-2, m axis JL-3 and n axis JL- 1. The section height is changed to 1 100, and the reinforcement and reinforcement position are constructed according to the original drawings. When the ground beam concrete is poured, plain concrete with the same label as the original beam is poured under the original beam at the same time, and the added ground beam intersects with the foundation surface of the tower crane. When pouring the surface of tower crane foundation, on the center line of ground beam, use 30×30 embedded battens to leave tongue-and-groove water-stop joints.

At the basement floor elevation of -8.3, concrete will not be poured for the time being between the ⑤ axis and the ⑦ axis, and between the M axis and the N axis. Only within the reserved hole position of the beam peripheral plate and the thickness of 350, the upper Φ14 @ 200 bidirectional reinforcement and the lower Φ14 @ 200 bidirectional reinforcement of the beam peripheral plate all extend out of the beam for 350 long, and the other Φ 650 is attached.

The tower passes through the second-floor underground roof at an elevation of -4.5, and is ready to be connected with the civil air defense junction R04. The 300×700 beam between axis ⑤ and axis ⑤ moves 400 in the direction of axis ⑤. The distance from the beam to the ⑤ axis is 1800, and the distance from the foundation center to the M ~ N axis is 3650.

L9 and L 10 on1m axis and 2/M axis shall be constructed according to the drawings. The upper part of the beam peripheral plate φ 16 @ 14 @ 65438 is only allowed in the reserved hole position of the beam peripheral plate, and the plate thickness is within 300.

Steel bars all extend out of the beam for 350 long, with φ 16 @ 300 attached, and φ 14 @ 300 all extend out of the beam 180 long. After the tower crane is dismantled, formwork support, steel bar welding and micro-expansive concrete one grade higher than the original concrete are poured according to the original design requirements.

2. Before installation, proofread the concrete foundation and check the concrete test report to ensure that the concrete grade is not lower than the manufacturer's design requirements.

3. Fixed legs: four 800-high fixed legs and eight pin shafts are needed; 1 fixed frame and 8 pins; 1 tower standard section; 1 plumbum thallium and a level.

A, fixed legs must be installed symmetrically according to the center line of concrete foundation, and 40 thick steel plates should be added below;

B, tower adopts ∠200×20 angle steel and 600×600 square steel plate to form fixed legs;

C, must ensure that the installation size of fishplate is150 mm; ;

D, fixed feet should be properly grounded according to electrical requirements;

E, assemble the fixed leg and the fixed frame (the fixed frame is only used for temporarily burying the fixed leg);

F, placing the fixed leg and the fixed frame on the steel bar, and adjusting the position of the fixed leg with the wooden wedge below the fixed leg supporting plate;

G, tower standard section on the fixed frame after the installation, check its verticality from two directions;

H, pouring tower crane foundation concrete, and after drying, removing the fixed frame and the standard section of the tower body.

4. Install the foundation and the second quarter, pay attention to the direction of climbing claws, board the scaffold, and board the operating platform on the scaffold.

5. Connect the slewing mechanism, cab and operating platform into a whole on the ground, and install the possible electricity. Then, hang this assembly on the tower, connect it with a lock shaft and install a safety lock. Pay attention to the direction in the process.

6, lifting the top of the tower:

Before hoisting, install the platform escalator on the top of the ground, then install the top of the platform on the turntable and fix it with pins and bolts.

7. Assemble the balance arm and the pull rod lifting mechanism on it. Connect the steel wire of the main winch, lift the main part of the balance arm, connect the balance arm pull rod with the tower top point with a pin shaft, and connect the power supply.

8. In the positive direction of the tower crane (according to the site conditions), assemble the boom and the pull rod pulley block, the trolley traction mechanism, repair the hanging fence, connect the boom with the front root of the tower cap with a car crane, and pull up the pull rod with the main winch to connect with the top of the tower.

9, heavy assembly, according to the requirements of the drawings can't dislocation, finally use screws to fix the counterweight.

10, connect the vehicle power supply, and thread the steel wire rope.

1 1. After the main tower is completed, check whether all the structures are firm and whether the transmission mechanism (including wire rope and pulley) is normal. Debug electrical and safety devices, and add components after confirmation.

Five, tower crane jack-up procedures and requirements

1, preparation before jack-up:

(1) Hoist the standard joint to the positive direction of the tower crane, clean the pin hole and pin shaft of the standard joint, apply grease, and carry out cleaning and refueling test on the hydraulic station.

(2) Put on the jack-up hook, lift the imported trolley, lift the first tower, pay attention to the direction, mount the imported track, knock off the connecting pin between the turntable and the tower, and the rotation is in a braking state. Jack up 15CM, introduce balance with trolley, and make the balance point fall on the top beam. /kloc-after 0/5 minutes, check whether the oil cylinder is slipping.

(3) In the process of jack-up, check the verticality of the tower from both sides to avoid deviation between the tower and the building.

2, the top work:

(1) After all parts are normal, jack-up is started. The pawls at both ends of the jack-up beam fall on the tower ears, the tower head is jacked up by 0.8m, and the pawls on the top beam fall on the tower ears. Retract the top beam of the oil cylinder and hang it on the upper pair of lifting lugs, then jack up the tower head and pull up the rack pawl. When the oil is fully extended, it will be about 1 m before the rack pawl can be installed. Retract the lifting beam of the oil cylinder and pull it to the upper pair of lifting lugs, then jack up the tower head and pull up the sleeve pawl. When the oil cylinder is fully extended 1.5m, be careful not to let the scaffold roller rush out of the tower, pull the scaffold into the imported trolley to make the standard section in place, turn the joystick to the lowered position, and the standard section will fall into the fishplate, connect it with a pin shaft, and insert a safety pin to lock the standard section.

(2) Lift the imported trolley, install the standard section and hoist it into the track. Drive the car to the balance point, remove the safety pin, and repeat it every (1) section until it reaches the required height. Before tripping in, connect the rotary table and the standard joint with 8 pins.

(3) In the process of jack-up, someone should open the hydraulic station and see the pawl and lifting lug clearly. When the wind speed is greater than level 4, jacking is not allowed. If there is any abnormality in the hydraulic system during jack-up, stop jack-up immediately, and nail the tower head on the tower. When the height exceeds the free height, bury the embedded parts in advance and attach them.

3, tower accessories

(1) This tower crane is composed of the fixed attachment frame provided by the manufacturer, and the bars and embedded parts are processed according to the drawings provided by the manufacturer.

(2) The estimated installation height of this project is 70 meters, and only one accessory is needed, which is determined to be at the height of 30 meters.

(3) The vertical distance from the tower center to the building is 3.5-5M depending on the actual situation.

(4) The horizontal error of the attachment rod shall not exceed 200mm.

Six, tower crane disassembly safety technology

I. Technical inspection before disassembly and assembly

Before disassembly and assembly, a comprehensive inspection shall be conducted to prevent any hidden danger caused by negligence and ensure safe operation.

1, check whether the subgrade and concrete fixed foundation meet the technical requirements.

2. Carefully check the mechanism, components, structural welds, bolts, shafts, hoisting mechanisms, wire ropes, hooks, spreaders, electrical equipment and lines of the tower crane, and solve the problems immediately when found.

3. Check the hydraulic cylinder and tubing of jack-up hydraulic system, jack-up jacket structure, guide wheels, lifting shoes and climbing claws, and handle the problems in time when found.

4. Check the main and auxiliary ground anchors, lifting wire rope of landing tower, braking system of lifting mechanism, etc. The rotating tower body method is adopted for disassembly and assembly, and it can be used only after it is confirmed.

5, tools, seat belts, helmets, etc. Those used by dismantlers should be thoroughly inspected, and those unqualified should be replaced immediately.

6, check the auxiliary machinery in the demolition work, such as cranes, transport vehicles, etc. Must have good performance, technical requirements can ensure the need of disassembly.

7. Check the relevant conditions of the demolition site, such as whether the power supply, transportation road and work site are ready for demolition.

8. The setting of safety supervision posts and the implementation of safety measures meet the requirements.

Second, the safety technology in the disassembly operation

1, the disassembly and assembly of tower crane must be carried out during the day. If you need to speed up the progress, you can do some assembly work at night with good lighting conditions, not in strong winds, dense fog, rain and snow.

2. During installation or disassembly, the site must be kept clean and orderly, and sundries shall not be piled up, so as not to interfere with operation and affect safety. Wood square must be placed under the metal structure of tower crane to prevent damage to the structure or structural deformation.

3, installation and erection of steel wire rope and its fixation must conform to the standards and meet the installation requirements. Temporary facilities such as ground anchors must be firmly constructed, especially before disassembly. The ground anchors used during installation must be carefully checked to ensure that they are still solid and reliable.

4. Before assembling or installing the parts one by one, the integrity, connection, wire rope threading and electrical circuit of the parts must be thoroughly inspected.

5. In the erection process, the stress on the structure and steel wire rope is the most unfavorable in the initial stage of tower erection, and decreases gradually with tower erection. In the process of dismantling the tower, the stress is the greatest when the tower is about to lie down completely. Therefore, when the tower starts to lift or is about to fall, it must be done slowly, and the inspection and observation of the main components should be strengthened.

6. Always keep the crane balanced when removing the jib and counterweight. It is forbidden to remove only one arm and interrupt the operation.

7. In the process of disassembly, if it is impossible to continue the operation due to sudden power failure, mechanical failure, sudden weather change and other reasons. Or when the operation time has come to a stop, the components installed and disassembled by the crane must reach a stable state and have been locked firmly, all structural components have been firmly connected, and the center of gravity of the tower top is at the center of the four sides of the tower bottom support. Only after inspection and confirmation can the operation be stopped.

8. During installation, the specified bolts, pins and other connectors shall be used according to the installation requirements, and reliable locking or protection devices shall be provided. When tightening bolts, the specified pre-tightening force should be added. Wire rope installation should strictly implement GB 5972-86 "Operating Rules for Inspection and Scrapping of Wire Ropes for Hoisting Machinery".

9. When installing the crane, the traveling limit device of the cart and the buffer of the limit device must be installed firmly and reliably. And assemble all parts of railings, platforms, chains, handrails, fixers and other safety protection devices.

10. When disassembling a crane that cannot be disassembled by normal methods due to damage, there must be a disassembly plan approved by the technical safety department to ensure safety.

1 1, installation procedures, auxiliary equipment, rigging, tools and ground anchor construction, etc. , should be handled in accordance with the provisions of the machine manual or refer to the standard installation process.

Three, jack-up and high safety technology

1, hydraulic system

(1) Hydraulic oil must conform to the varieties and labels specified in the original manual. If it is necessary to substitute, its performance must be the same as or similar to the original variety and label, and it is not allowed to substitute at will, nor to mix two different hydraulic oils.

(2) The hydraulic oil and hydraulic system must be kept clean and free of impurities such as dust, moisture, metal chips and rust. The amount of oil in the oil tank should be kept at the normal oil level. When changing oil, the hydraulic system should be thoroughly cleaned and new oil must be filtered. The container containing hydraulic oil must be kept clean, and the inner wall of the container shall not be painted.

(3) The hydraulic oil pipe joint shall be firm and shockproof, and the hose shall not be sharply bent or twisted, and shall not collide and rub with other pipes or objects.

(4) The inlet, outlet and rotating direction of the hydraulic pump shall be consistent with the signs. Do not knock when removing the coupling.

(5) The hose connection of hydraulic cylinder shall not be loose, and the entrances and exits of valves shall not be installed backwards. The flange screws shall be tightened with pre-tightening force as required.

(6) When the hydraulic pump starts and stops, the relief valve should be unloaded, and the regulating pressure of the relief valve should not exceed the maximum pressure of the hydraulic system.

(7) The connection seal of each part of the hydraulic system must be reliable without leakage, and the interlock device must be verified.

(8) When opening the air valve or checking the leakage of the high-pressure system, don't face the direction of the injection port.

(9) When slight or partial blowdown occurs in the high-pressure system, it shall be unloaded and overhauled immediately, and the blowdown shall not be checked or blocked by hand.

(10) When the hydraulic system fails or has an accident, it must be unloaded before it can be inspected and adjusted.

2, jack-up operation

(1) Before jack-up, it is necessary to check the connection of various parts of the hydraulic jack-up system, adjust the gap between the guide roller of jack-up jacket and the tower, then loosen the cable with a length slightly greater than the jack-up height and fasten the cable drum.

(2) Jack-up operation must be carried out under the command of special personnel. Non-operators are not allowed to board the jack-up jacket console. Only one person is allowed to operate the operating room, and strictly obey the signal command.

(3) Jack-up should be carried out during the day, and under special circumstances, there should be enough lighting for night work.

(4) When the wind force is above level 4, jack-up operation is not allowed. If the wind suddenly increases during the operation, the operation must be stopped immediately, and the upper and lower towers are firmly connected.

(5) During jack-up, the boom and balance block must be in a balanced state, and the rotating part should be braked. Operations such as rotating the boom are prohibited. If any fault is found in the process of jack-up, the jack-up must be stopped immediately for inspection, and the jack-up can be continued after the fault is eliminated. If the fault cannot be eliminated in a short time, the jack-up jacket should be lowered to its original position and the connecting bolts should be tightened in time.

(6) When removing the connecting bolt (pin) between the tower and the standard section of the tower body, if it is difficult to remove and assemble the last bolt, the diagonal bolt (nipple) should be reinserted and other measures should be taken. Do not loosen the bolt (pin) by rotating the boom.

(7) During jack-up, before the next action, it must be confirmed that the jack-up bracket is firmly in place.

(8) During the jack-up operation, pay attention to the pressure change of the hydraulic system at any time, and check and adjust it in time if there is any abnormality. There must also be a special person to measure the verticality change of the tower with theodolite and make records.

(9) After jacking to the specified height, the tower must be attached to the building to continue jacking.

(10) When jacking during disassembly, the precautions are the same as above. However, the anchorage device shall not be dismantled in advance, and it can only be dismantled when the anchorage device descends to the attachment joint.

(1 1) After jack-up installation and disassembly, the connecting bolt pin shall be fastened according to the specified preload, the guide wheel of jack-up sleeve shall be in good agreement with the tower, the left and right joysticks of hydraulic system shall be in the middle position, and the power supply of hydraulic jack-up mechanism shall be cut off.

Fourth, the safety technology of online operation

1, tower crane attached to the building, its stress intensity must meet the requirements of tower crane attachment.

2. According to the total construction height, structural characteristics and construction progress requirements of this project, the following attachment scheme is arranged: two anchorages are set, the distance between attachment brackets is 1500m, and angle steel attachment rod system and corresponding attachment technology are adopted.

3. When installing the attachment frame and the attachment rod, use theodolite to observe and adjust the attachment rod to ensure the verticality of the tower.

4. The attachment frame should be set at the standard joint of the tower as far as possible. When the tower is tightened, diagonal braces should be set to reinforce the tower.

5. With the jack-up and assembly of tower section, the added anchorage should be attached to the building in time. The free height of the tower above the anchoring device shall generally not exceed 40m.

6. When multi-channel anchorage devices need to be set in the construction of super high-rise buildings, the lower anchorage devices can be transferred to the upper part for use. But the distance between the first anchorage and the tower crane foundation shall not exceed 50m. The layout of each anchoring device shall comply with the relevant provisions in the instruction manual.

7. The place where the attached bearing is laid must be reinforced, and the label of concrete should be appropriately improved. When connecting, the structural strength of the connecting bracket must meet the design strength. Attached bearings are set on the cast-in-place concrete inner wall panels, and supports and steel bars must be set between the wall panels (this span and adjacent spans). (When the attachment bearing is fixed on the floor, steel bar support should be set between the two floors. ) Attached bearings should be fixed firmly, and the gap between them and the building structure should be tightly plugged.

8, in the process of operation, must often check the anchoring device, found loose and abnormal situation, should immediately stop the operation, failure is not completely eliminated, shall not continue to use.

9. When disassembling the crane, the corresponding anchoring device should be disassembled together with the landing process. It is forbidden to remove the anchoring device before falling off the tower.

10, it is forbidden to install or dismantle anchoring devices in strong winds of magnitude 6 and above.

1 1, the installation, disassembly, inspection and adjustment of the anchoring device shall be the responsibility of the special person, and the safety belt and helmet shall be worn during operation, and the relevant provisions of the Safety Operation Regulations for Aerial Work shall be observed.

Five, the safety technology of climbing operation

(1) Climbing operations should be carried out during the day. When the wind exceeds level 5, the operation should be stopped.

(2) When climbing, we should strengthen the connection between the upper and lower floors, and strengthen the connection between the upper and lower floors. If there are faults and abnormal conditions, stop the machine immediately for inspection. Don't continue climbing unless the fault is eliminated.

(3) During climbing, lifting, turning and luffing are prohibited.

(4) After the tower crane climbs to the specified height, it shall immediately pull out the supporting beam or leg of the tower foundation and fix it on the floor through the climbing frame to bear the vertical load from the upper part of the tower crane.

(5) The tower crane is attached to the floor through the guide device, wedge and climbing frame. Therefore, the guide device should be pushed or wedged immediately after climbing to bear the horizontal load. The attachment spacing of internal climbing tower crane should generally not be less than 3 layers.

(6) For floors with climbing frames, all floors below should be temporarily reinforced with columns. The two floors below the tower crane foundation supporting beam are temporarily strengthened with columns.

(7) After each climb, the holes left on the floor must be immediately closed with reinforced concrete.

(8) After the tower crane completes the climbing operation, it is necessary to check whether the attachment is firm, whether the climbing frame is fixed, whether the base support is fastened, and whether the temporary support on the floor is appropriate. , and confirm that there are no remaining problems, before lifting operation can be carried out at another floor height.

Technical inspection during the installation of intransitive verbs

Check the surface smoothness, concrete strength, embedded parts position and drainage ditch setting of the fixed foundation, which should meet the requirements.

1, walking underframe, foundation section and counterweight should be inspected after installation:

(1) The clamping degree of the rail clamp should be firm and reliable.

(2) The running gear brake shall be complete and in good appearance.

(3) The horizontal tie rod, diagonal tie rod and fixed pin shaft are installed completely, with correct positions and in compliance with regulations.

(4) The installation position (including horizontal and vertical deviation) of foundation section and underframe shall be within the allowable range, and the bolts or pins shall be complete and the fastening shall comply with the regulations.

(5) Ballast installation position is correct, and the weight conforms to the original specifications.

2, standard section, jack-up jacket, rotary platform after the installation should focus on inspection;

(1) Whether the model of standard section (refers to reinforced section or multiple standard sections) conforms to the provisions of the original factory manual; Pre-tightening force of standard section and foundation section bolts shall comply with technical regulations.

(2) Whether the relative position of jack-up jacket and standard section meets the installation process requirements; Whether the imported car is in the right direction. The connection between jack-up jacket and rotary table shall be firm and reliable, and the pre-tightening force of connecting bolts shall meet the technical requirements.

3. After the cab part and tower cap are installed, the following inspections should be focused on:

(1) The connection between tower cap and cab, cab and slewing platform shall be firm and reliable, and the pre-tightening force of connecting bolts shall meet the technical requirements.

(2) Detect the plane formed by each traveling wheel of the traveling trolley and the track support point, and the non-parallelism of the slewing support plane installed on the traveling underframe shall be no greater than11000.

(3) The verticality error between the axis of the detection tower and the bearing surface shall be no greater than 4/ 1000.

4, balance arm, jib, balance weight after the installation should focus on inspection:

(1) Whether the connection between the balance arm, the lifting arm and the tower is reliable, the connecting pin shaft should not move, and the fastening meets the technical requirements.

(2) Whether the connection between each section of the balance arm and the boom is reliable and whether the fastening meets the technical requirements.

(3) Whether the safety devices such as guardrails and fixers are complete, firm and reliable.

(4) Whether the cables (or tie rods) of the balance arm and the lifting arm are installed correctly, whether the stress is uniform, and whether the connection and fastening meet the technical requirements.

(5) Whether the weight, installation position and fixation of the counterweight meet the technical requirements.

(6) Test the power supply voltage of the cab, which should be 380% 5%.

(7) The trial operation of hoisting, luffing, slewing, walking (if necessary) and other working mechanisms shall be smooth and sound-free, and the braking shall be sensitive and reliable.

(8) Test the safety limit protection device, and the action should be sensitive and reliable.