Special construction plan for the erection and dismantling of the derrick of the comprehensive building?

What are the special construction plans for the derrick erection and disassembly of the comprehensive building? What are the common treatments? Please ask Zhongda to consult the editor for the article.

Special construction plan for the derrick erection and disassembly of the comprehensive building

1. Foundation treatment and methods

1. For the foundation, see attached picture (1)

2. The installation site must be leveled and compacted first. Installation on loose soil or subsidence fields is prohibited. The foundation bearing capacity is required to be greater than 80Kpa.

3. The foundation is poured with C30 concrete, with a thickness of not less than 500mm.

4. The foundation surface should be smooth and the horizontal deviation should not be greater than 10mm.

5. The foundation is equipped with drainage measures. Within 5 meters from the edge of the base road, measures must be taken to ensure the stability of the frame during trench excavation or construction with significant vibration.

6. When pouring the derrick foundation, personnel from the supervision company should stand by and take samples of the concrete. Make concrete test blocks for maintenance, and have concrete strength reports.

7. Various safety technical measures in front of the derrick and the status of the installation unit should be reported to the Municipal Construction Bureau for filing. The derrick erection can only be carried out after filing.

II. Technical requirements for frame installation

1. The vertical deviation of the derrick's full height should be less than 1.5‰ of the height. For the derrick, it is 27 meters, so the vertical deviation is controlled within 4cm.

2. The misalignment deviation at the cage guide rail joint shall not be greater than 1mm.

3. The diagonal error of the chassis shall not be greater than 5mm.

4. All connecting bolts must be tightened.

5. The installer must be an erecter holding a valid elevating erection operator certificate.

6. Wear safety belts when working at heights. A police area is designated under and within 3 meters around the derrick, and unrelated personnel are prohibited from entering the dangerous operation area.

7. The foundation should be complete before installation, the concrete curing is due, the test block report is qualified, and it should be reported to the relevant departments of the Construction Bureau for filing.

8. When the main body of the project has not caught up, use the wind rope to reinforce the derrick body. The wind rope should use a steel wire rope with a diameter greater than 9.3mm. The angle between the wind rope and the ground should be between 45 degrees and 60 degrees. During the installation period, the ground anchor should be firm and reliable, complying with the "Safety Technical Specifications for Gantry and Derrick Material Hoist" (JGJ88-92) and relevant specifications.

9. The installation of lightning protection down conductors and grounding bodies should comply with the requirements of lightning protection and grounding installation specifications, and their grounding resistance should not be greater than 10Ω.

10. The down conductor can be made of round steel, flat steel or copper wire, and its size should not be less than the following values. The diameter of round steel is 8mm; the cross-sectional area of ​​flat steel is 48mm2; the thickness is 4mm; the cross-sectional area of ​​copper wire is 10mm2.

11. Installation work is prohibited in winds above Level 5.

3. Rack installation steps and operation essentials

1. Before installing the rack, safety officers and rack workers should read the product instruction manual carefully, and solve all difficult problems by the safety personnel. Provide safety education and safety briefings to operators.

2. Place the chassis channel steel on the foundation and connect it with the chassis connecting angle iron. Put in the anchor bolts, level the chassis basically, and check the diagonal error of the inner corners, which should not be greater than 5mm. When pouring concrete, a certain gap should be left between the chassis and the concrete for the second grouting. After the concrete is basically dry, level the chassis again. The horizontal error is required to be no more than 1‰. Fill the concrete under the chassis channel steel again, and there should be drainage holes on all sides of the chassis.

3. Place two steel pipes or angle irons horizontally on the chassis, and place the cage flat on the chassis.

4. When installing vertical poles, flat braces, diagonal braces, and installing splayed braces at the feed port, two people are required to cooperate tacitly.

5. Install the guide rail tube

6. When the erection of the frame exceeds two steps, the erecter should set up a strong and reliable working platform and be required to wear a safety belt.

7. Repeat steps 3 and 4 until the required height is reached, and the remaining supports and splayed supports in the feeding and discharging directions are staggered.

8. During the derrick installation process, the hanging wires must be checked at any time to ensure verticality requirements.

9. The derrick is set up in one step.

10. During the erection, when the erection reaches the 8th step, a temporary cable duct should be set up. As the working layer moves up, the temporary cable duct will also move up. When the erection reaches the 10th step, a temporary cable duct should be set up. A permanent cable wind. Temporary cable wind ropes should still be installed when erection continues until the second permanent cable wind rope is installed after the erection reaches 27 meters.

11. After the main body comes up, the rigid ties of the completed part of the main body should be firmly tied before erection, and the work should be coordinated.

12. During the erection process, the scaffolder should set up a temporary operating platform at the same time. Generally, five 6cm wooden boards can be used as the operating platform, and they can be moved with the movement of the working layer.

13. φ9.3> steel wire ropes should be used as wind ropes for temporary fixation. A set of wind ropes should be added 15 meters above the top. The wind ropes should be set symmetrically and at an angle of 45 degrees to the ground. °-60° angle, the cable wind rope is fixed with ground anchors. The ground anchors should be set up side by side with no less than 2 steel pipes, with a spacing of 50 cm. The depth of penetration into the soil should be greater than 1.7 meters. Blue screws should be used. The openings should be secured and the ropes should be clamped on both sides. There should be no less than 3 ends, matching in diameter.

14. When the main body of the project is not going up, the derrick is fixed with wind ropes. After the main body of the project is going up, rigid tie-downs should be actively used. The rigid tie-down points should be set in a group of 6 and placed on the There is a group at the top level.

15. Install the heavenly wheel frame and the heavenly wheel pulley.

16. Install lightning rods, down conductors, overload limiters, TV monitoring, and docking communication systems as needed.

17. Install the winch.

18. At the unloading platform entrance, when the supports are to be removed, two additional eight-shaped supports must be added to meet the reinforcement requirements.

19. After installation, each transmission system should be filled with lubricating oil, and the moving parts should be greased with butter. Check whether each transmission system and safety device are sensitive and reliable.

20. After confirming that all parts are normal, no-load test, rated partial load test, overload test and safety device reliability test should be carried out according to regulations. Only after acceptance by the company's safety department can it be put into normal operation. use.

IV. Safety protection devices and requirements

1. The bottom of the hanging basket is laid with a 3cm thick iron plate, and safety nets with a height of 2m are set on both sides of the hanging basket and painted yellow. The paint mark is strictly separated from the red color of the frame. A protective net with a mesh size of 2cm × 2cm is used on the top of the hanging basket to achieve a fully enclosed effect.

2. Safety docking device. The main function is that when the hanging basket is in place, the docking device positions the hanging basket. The device should be able to reliably bear the weight of the hanging basket, the rated load and the working load of the people transporting materials and loading and unloading materials, and should be automatically interlocked with the discharge port door to enhance the safety of incoming and outgoing materials.

3. Rope break protection device. Main function: When the rope breaks during the operation of the hanging basket, it should be able to reliably stop and fix it on the frame. Its sliding stroke should not exceed 1 meter when the hanging basket is fully loaded.

4. Safety door of hanging basket. A safety door should be installed at the loading port of the hanging basket. The safety door color interlocking opening device can automatically cut off the super-lift power supply when the door is closed. The safety door closes the loading port of the hanging basket during lifting operation to prevent materials from rolling down from the hanging basket.

5. Upper limit limiter. The device should be installed at the highest working position where the hanging basket is allowed to be lifted. The overreach of the hanging basket (referring to the distance from the highest position of the hanging basket to the lowest point of the sky beam) should be no less than 6 meters. When the hanging basket rises to the limited height, the limiter will act immediately and cut off the power supply.

6. Emergency power-off switch. The emergency power-off switch should be set in a position that is convenient for the driver to operate. In an emergency, it should be able to cut off the main control power of the hoist in a timely manner.

7. Signaling device. This device is a TV monitoring device controlled by the driver. Its image should be clearly visible to personnel using the elevator to load and unload materials on each floor.

8. Lower limit limiter. The installation position of the limiter should be such that the limiter can move before the hanging basket hits the buffer. When the hanging basket descends to the lowest limit position, the limiter automatically cuts off the power supply and stops the hanging basket from descending.

9. Buffer. A buffer should be installed in the bottom pit of the frame. When the hanging basket acts on the buffer at the rated load and specified speed, it should be able to withstand the corresponding impact force. The type of buffer can be spring or elastic entity.

10. Overload limiter. When the load reaches 90% of the rated load, an alarm signal should be issued. When the load exceeds the rated load, the over-rated power supply will be automatically cut off.

11. A protective shed should be erected at the feed port of the derrick. The protective shed should be located above the ground feed opening of the lifting frame body. Its width should be greater than the outermost dimension of the elevator; length: the elevator protective shed should be greater than 5 meters, and its material strength should be able to withstand a uniform load of 10KPa or use two layers of bamboo fences. The upper and lower fences should be laid vertically and the spacing should not be Less than 600mm.

12. Protection requirements for the unloading platform. The unloading platform on each floor should be set up separately and is not allowed to be connected with the outer frame or derrick. The unloading platform should be assembled and tightly assembled with 4cm thick wooden boards. There should be protective railings on both sides and fully enclosed with safety nets or scaffolding pieces. The feed port should have a standardized and tooled safety door with red and white warnings. Painting.

13. Frame enclosure. Three sides of the frame (except the discharge port) are fully enclosed with an 800-mesh safety net. A double-layer protective shed with a height of 3.6 meters is erected at the feed inlet and erected separately. It must not be connected to the frame body and the outer frame unloading platform.

5. Installation and operation requirements of the winch

1. The winch is installed smoothly and firmly. The distance from the ground pulley (the drum center distance) should be greater than 15 times the width of the drum.

2. The wire rope on the drum should be wound neatly, no less than 3 turns, and a protective cover should be installed on the edge of the drum to prevent the wire rope from coming out.

3. The winch operating shed should be equipped with a double-layer anti-smash shed in addition to rain protection, that is, a double-layer protective shed. The distance between the two layers should not be less than 60cm, and the sight line should be between the hoist and the unloading platform. should be good.

4. The winch wire rope should be equipped with a channel and a cover plate with an observation opening.

6. Dismantling of the frame body (the specific dismantling plan shall be reported to the Safety Department before dismantling)

1. Before the derrick is dismantled, the derrick dismantling record must be completed in accordance with relevant requirements. After reporting to the construction Demolition can only be carried out after filing with the relevant departments of the bureau.

2. Before dismantling, a dismantling construction plan must be prepared, safety technical briefing and safety re-education must be conducted for the installation team members, and the dismantling operation can only be carried out after submitting it to the Construction Safety Department for approval.

3. Dismantling plan

① Installation workers who are weak or sick are not allowed to participate in the lifting and dismantling of the derrick.

② Set up a warning boundary before demolition. It is strictly forbidden for other personnel to enter and exit the police area at will. The necessary passage must be approved by the commander and the supervisor.

③ Before dismantling, you should check whether there are wires, machinery and other dangerous items underneath you, and take preventive measures to clear the site.

④ Dismantling personnel should wear safety helmets, buckle their hat straps, and fasten their seat belts.

⑤ When dismantling, materials should be dropped smoothly. Throwing is strictly prohibited. Doors, windows, glass, downpipes, exterior wall decorations and other items should not be damaged.

⑥ It is strictly prohibited for personnel to work vertically up and down at the same time.

⑦ Clear the demolition materials on the same day, classify and stack them neatly, and carry out civilized construction.

⑧When dismantling, a stable operating platform must be set up.

7. Calculation of the load limit of the derrick unloading platform

In order to ensure the safety of construction and standardize the safety management of the construction site, the load limit of the derrick unloading platform is now calculated. According to the construction site The actual situation can be known:

1. The unloading platform is assembled with 4×6 square files. Check the "Building Construction Manual" to find that the bending resistance Fm=13N/mm, the pressure resistance and pressure-bearing FC=10N/ mm2, the 4×6 square stall has a self-weight of 330KN/m2.

2. According to the lifting weight limit of the derrick, the project department stipulates that each time the hanging basket is lifted, it can only lift two loads of goods.

3. This project is a fully cast-in-place structure, and the main transportation material is plain concrete. There is no prefabricated floor slab installation process.

4. Unloading platform load calculation:

The volume of the trolley is 0.2m3, the number of bricks in a trolley is 50, and the trolley’s dead weight is 25kg.

The self-weight of 2 cars of concrete: 25×0.2×2=10KN

The self-weight of 2 cars of hollow bricks: 2×15×50×0.24×0.115×0.09=3.726KN

From the above calculations, we know that the load capacity of the unloading platform is a 4×6 square file The pressure-bearing capacity of the 4×6 square frame is FC=10/mm2, but we cannot say that the load-bearing capacity of this unloading platform is 10 tons, because the unloading platform is made of steel pipes from the outdoor floor. It is built from the ground up, so the steel pipe frame must meet the requirements.

5. Check the steel pipe frame

Because the calculated bearing capacity of the steel pipe frame under the axial compression strength condition is FN≤81.32KN, but the steel pipe frame at the steel pipe at the unloading platform The load transmitted from the large horizontal bar to the vertical bar is only transmitted through the cross fasteners, so it cannot be the axial compression. Under the action of eccentric axial load, the bearing capacity of the steel pipe is only (0.19~0.14) PN, which is 11.4 ~15.4KN.

For this reason, we can set the limit load to 10T, but it is impossible to have such a large value at the construction site, so we can set the limit of 66 derricks (basket) to be slightly larger, in order to prevent Take 2T as the load limit.

The above is collected and compiled by Zhongda Consulting

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