Formwork engineering is an important part and necessary condition of concrete component forming. Collapse accidents occur from time to time due to design errors, irregular construction, inadequate inspection and unqualified materials.
1. Construction scheme: Before erection, a special scheme shall be made, including the design, fabrication, installation and removal, construction sequence and operating conditions of formwork and support. , and provide detailed calculations and drawings to guide the construction. According to the examination and approval authority, the high formwork scheme should be demonstrated by experts.
2, set up monitoring and alert.
3. Acceptance before use.
4. Safety monitoring and vigilance in the process of demolition.
Two, "Three Treasures", "Four Ports" and Frontier Defense
"Three treasures" mainly refer to protective articles such as safety helmets, safety belts and safety nets; Its manufacturers must have the National Production License for Industrial Products issued by the General Administration of Quality Supervision, Inspection and Quarantine and the Safety Production License for Special Labor Protection Articles issued by the State Administration of Work Safety.
"Four ports" mainly refers to the protection of various openings such as stairs, elevator wellhead, reserved port and maintenance port.
1, helmet
★ Used to protect the user's head. The national standard code is GB28 1 1-8 1. On each helmet, there should be the following three permanent marks:
Name, trademark and model of the manufacturer;
Year of manufacture;
Production license number.
★ Service life of safety helmet: rattan shall not exceed two years; Plastic surgery is not more than two and a half years; Glass fiber reinforced plastic is not more than three years flat. Expired helmets should be spot-checked and tested.
2. Safety net
★ In the process of engineering construction, in order to prevent falling objects and reduce pollution, a dense mesh safety net must be used to completely enclose the building.
When the external scaffold is constructed, it should be closed with dense mesh safety net along with the elevation of the frame body;
★ The dense mesh net is used to erect the net, and its structure is that the mesh density should not be less than 2000 mesh/100cm2.
★ Each safety net factory glue must have batch verification and factory inspection certificate from the supervision and inspection department designated by the state.
3. Seat belts
★ Seat belts are mainly used as protective articles to prevent people from falling. All personnel who work independently in the construction site must wear seat belts.
★ Correct use: The length of safety belt rope used by scaffolder is limited to 1.5-2m.
★ It should be hung vertically, hung high and used low, not hung low and used high, and not tied with ropes.
4. "Four" and limb
★ Stair step and rest platform mouth
Stair steps and rest platforms must be protected by two solid protective railings or hanging safety nets. The first layer of safety flat net should be set between the rotating ladders.
★ Elevator wellhead protection
A metal protective door with a height of not less than 1.2m must be installed at the elevator wellhead, and a horizontal safety net should be set at the first floor and above every four floors in the well, and the safety net should be tightly closed. Without the approval of the technical department, vertical transportation or garbage passage is not allowed in the elevator shaft.
★ reserved hole protection
The holes below 1.5m* 1.5m shall be embedded with long steel mesh or fixed cover plate. For the hole above 1.5m* 1.5m, two protective railings must be set around, with a horizontal safety net in the middle.
★ Protection of buildings and entrances and exits
A protective shed should be erected at the entrance and exit of the building, with a length of 3-6m (the specific length should be greater than the "possible falling range radius r" in the Classification of Work at Height (GB/T3608-93)), and the width of both sides of the entrance and exit channel is 1 torch plane. The roof should be covered with wooden boards with a thickness of not less than 5CM, and both sides of the entrance and exit channels should be sealed.
When the height is 2-5 meters, R is 3 meters; When the height is 5- 15m, r is 4m; When the height is 15-30m, r is 5m; When the height is more than 30 meters, R is 6 meters.
In the vicinity of the construction area, where there is a threat to people or things, protective sheds must be erected.
★ Protection of balcony edge and floor edge
Balcony railings should be installed along the floor. If it cannot be installed in time, two protective railings must be set up, or a safety net must be set up to close it.
Protection of Building Floor Edge
When there is no maintenance structure around the edge of the building floor, two protective railings must be set up, or a safety net and protective railings must be erected.
Third, the material hoist (gantry, derrick)
1. Scaffolding: It must be designed and calculated in accordance with the requirements of Technical Specification for Safety of Gantry and Derrick Material Hoists and approved by relevant departments. At present, homemade products are generally not allowed. You should buy a set of products with up-and-down contact signal devices.
2. Safety device: When the hanging basket is in place, the operator needs to transport materials in it, so it needs safety stop device, rope breaking safety device, superelevation limiter, lower limit limiter, buffer and overload limiter. When the wire rope of the hanging basket is suddenly disconnected, ensure that the staff in the hanging basket are not hurt.
3. The frame body is connected stably: cable wind rope and ground anchor are adopted; Adopt a connection mode with that main structure.
4. Safety requirements for the unloading passage: protective railings should be set on both sides of the passage according to the border defense regulations; A safety door should be set at the entrance of the hanging basket, and the safety door should be finalized. Personnel are not allowed to get on or off the passenger basket at any time. Single rope lifting is prohibited.
5. Installation and disassembly: Make a plan before installation and disassembly, make disclosure, set up a warning zone, and use it after inspection and acceptance.
6. Others: It is forbidden to use the reverse switch as the winch control switch. Wire rope crossing should be covered. The hoisting drum and guide wheel should be vertically aligned, and the distance between them should not be less than 20 times the diameter of the drum. The operation shed should be rain-proof and smash-proof. Close the electric lock box after work.
Four. External elevator (dual-purpose elevator for people and goods)
1. General provisions: there should be obvious weight limit signs when using.
The external elevator device includes: brake, speed limiter, door interlocking device, upper and lower limit devices and upper limit switch. A solid fence must be set within 2.5 meters around the elevator cage, and a protective shed should be set at the upper part of the entrance and exit. The elevator passes through bridges and passages to reach each floor, with protective railings on both sides and protective doors at the entrance and exit. The protective door is generally closed and can only be opened when the ladder cage runs to a certain floor.
2. Installation and disassembly: Work out the operation plan according to the instruction in advance and make disclosure with the supervisor. Operators should be held by a professional team with professional qualification certificates and commanded by designated personnel. After installation, acceptance shall be carried out according to regulations. Before use, it should be tested by professional testing institutions, and it can be officially used only after it is qualified.
3. Operation: Operators are special operators and must be trained and hold qualification certificates.
There should be a two-way communication system. Check the travel switch and limit switch every day. The 6-level gale stopped the operation.
Five, tower crane
1. Installation and disassembly: The installation and disassembly of tower crane is a complicated and dangerous work. Safety devices such as lifting moment limiter, lifting weight limiter, limiter, safety device and wall-attached device shall meet the requirements of installation instructions and specifications. The corresponding requirements must be strictly implemented:
★ Prepare the disassembly plan before operation. For jack-up operation of jack-up tower crane, balance must be maintained between the boom and the balance arm, and reliable measures should be taken to prevent rotation.
★ The installation and disassembly of tower crane must be carried out by a professional team with corresponding qualifications, and the personnel involved in the operation must hold a work license and be commanded by a special person. Tower crane drivers and commanders are special operators and must hold relevant certificates.
2. Installation acceptance: * * * There are three situations: before delivery, after maintenance and before reuse.
3. Usage: Lifting includes structure lifting and equipment lifting, which is a dangerous operation at high altitude, with changeable working conditions and complicated construction technology. The following requirements must be observed:
★ Prepare a special plan before hoisting, with calculations and detailed drawings. The plan should be targeted and approved by the technical department;
★ Choose hoisting machinery according to the scheme, conduct on-site assembly and acceptance inspection, and check all kinds of safety devices.
Taken the tower crane driver and commander are special operations personnel, must hold relevant certificates.
4. Others:
★ Before it is officially used, it must be tested by local professional testing institutions and hung with qualified cards.
★ There are overhead wires within the working radius of tower crane, so special measures must be taken to protect and warn.
★ When multiple tower cranes run in parallel, anti-collision measures should be taken.
★ If the tower crane is used over the free height, a wall-attached device must be installed. Non-standard wall-attached equipment shall be designed by special personnel and approved by the technical department.
Six, the construction of electricity safety management
1, basic requirements for temporary electricity safety:
The project department shall formulate the electricity safety system;
Construction site with five or more units or capacity of 50KW or above shall prepare the Construction Organization Design for Temporary Electricity Consumption, and construction site with five or less units or capacity of 50KW or below shall formulate technical measures for safe electricity consumption and electrical fire prevention measures.
Check the temporary power consumption items once a week;
Electricians should hold valid certificates, and two people should cooperate with electricians to operate. They should wear insulated shoes, gloves and tools as required.
The distance between the project under construction and the external power line, and the minimum height when the motor vehicle lane crosses the external power line. Can not meet the requirements, take protective measures, and hang warning signs.
2, electricity system requirements:
When the power supply system with independent neutral point directly grounded is adopted, the field power consumption must be "TN-S" (three-phase five-wire system), and the equipment shell must be connected with protective zero line. (When TT system is adopted, the equipment shell is connected with protective grounding wire).
3. Distribution box and switch box
"Three-level distribution (main box, distribution box and switch box) and two-level protection (main box leakage protector and switch box leakage protector) must be achieved.
It must be "one machine, one brake and one leakage box" (that is, each electrical equipment is specially equipped with a switch box, and only one knife switch and one leakage switch are installed in the switch box).
4. On-site lighting:
The metal shell of lighting lamps and lanterns must be protected by zero connection or grounding. Leakage protector must be installed in the lighting switch box of single-phase circuit.
Several situations of using safe voltage: the distance between indoor lights and indoor powder is less than 3 meters and 2.4 meters, and 36 V should be used;
Use traveling lights (i.e. hand-held mobile lights), and the power supply voltage is not more than 36V；;
The power supply voltage of tunnels and civil air defense projects is not more than 36v；;
The voltage in wet places shall not be greater than 24V；;
In particularly humid places and metal containers, the power supply voltage shall not be greater than12v; ;
5. Distribution lines
Overhead lines must use insulated conductors. Cable trunk lines are buried or overhead, and laying along the ground is strictly prohibited. It is not allowed to soak the cable in water for a long time, and it is not allowed to cross the road without protective measures.
6, electrical equipment
The electrical switch in the distribution box shall be fixed well and shall not be damaged, and the leakage switch shall be installed on the load side of the power isolating switch.
Seven, construction machines and tools
1, woodworking machinery
Safety device:
The chainsaw has a protective cover distributor, and the transmission part is protected;
The planer is protected.
It is forbidden to use reverse opening and control.
2, steel machinery
The tool can only be loaded after normal operation; When the steel bar is bent, the personnel position must be correct.
3, concrete, mortar mixer
The installation is firm and stable. Clutch, brake, wire rope and feed hopper are in good condition.
When you enter the drum to clean the chisel, you must cut off the power supply and someone is watching outside.
4. Explosive rammer
The length of power cable shall not exceed 50 meters. Operators should wear insulating gloves and shoes. Two people work together, one is in charge of the wires and the other is in charge of the operation.
5, electric welding machine
The welding machine should be placed stably, the primary side of the power supply must be controlled by the electrical protection switch, the primary power supply line should not exceed 5 meters, and the protective grounding/zero connection of the casing is reliable.
The length of secondary line of electric welding machine shall not exceed 30m.
No-load anti-electric shock device should be installed on the secondary side of electric welding machine.
The copper wire nose is used for primary and secondary side wiring, and the wiring point has a protective cover.
6. Oxygen and acetylene cylinders for gas welding
Special hanging cages should be used for high-altitude hoisting; It is forbidden to expose the gas cylinder or be polluted by oil.
The gas welding operator shall ensure that the distance between the bottle and the fire source is above10m.
Acetylene bottles should be equipped with anti-backfire devices.