Building Construction and Supervision (Basic Knowledge of Construction Safety)

The characteristics of construction production are fixed products and personnel flow, and most of them are open-air and high-altitude operations. The construction environment and operating conditions are poor. Unsafe factors are constantly changing along with the progress of the project image, with poor regularity and hidden dangers. Therefore, the construction industry is one of the accident-prone industries. As the main force of urban construction, our construction and construction companies are pursuing maximization of benefits while promoting social progress and promoting urban construction. This is the most fundamental goal of our construction companies. However, safety is efficiency. Safety is our lifeline. Safe production is the best treatment for our country and our people.

"Safety First, Prevention First" is the guideline for safe production in China. Safety management is an important part of business management. It encompasses the entire process, all aspects of the construction site, and all personnel. Therefore, as all our safety production management personnel, we must pay close attention to politics, ensure stability, and take a highly responsible attitude toward the country and the people, and pay close attention to the work safety management. Here are some aspects of safety production supervision. The key content of management work:

In order to enter the construction site, it is first necessary to check whether the software assurance information of the project is complete, whether the records of various security accounts are timely, whether there are complete procedures, whether the various production safety responsibility protection systems and on-site safety production management networks have been established and improved. Production responsibility system, etc.

First, the whole production responsibility system:

The so-called safety production responsibility system is in the form of a system that clearly defines the safety responsibilities of leaders and personnel at all levels in the production activities. It is the most basic system in the safety management of enterprises and is the core of all safety regulations. It mainly includes the following three aspects:

1. The safety responsibilities of leaders at all levels of the company.

As our construction and construction company, it includes the production safety responsibility system of corporate legal persons, branch managers, chief engineers, project managers, construction team leaders, and security personnel.

2. Responsibility for safe production of relevant functional departments of the company.

It includes the production department, technical department, mechanical equipment department, material department, etc. Each functional department is responsible for the safety of the department within its own responsibility.

3. Safety duties of front-line workers.

It includes various types of work: brickwork, carpentry, steel workers, shelf workers, welders, electricians, lifting workers and other types of work safety production rules and regulations.

The construction site project manager is the first responsible person for the project's safety production and bears overall responsibility for the safety of the project.

After establishing and improving the above-mentioned various responsibility systems for safety production, it is imperative that the responsibilities be carried out to specific personnel and that the objectives of the previous phase be regularly assessed.

Second, whether there is a complete safety production and construction organization design scheme at the construction site and the main contents that must be specified in the plan.

1. The total design of safety production and construction organization

In a construction site, if there is not a complete organization for the design of safety production and construction, it is not safe to think of where to do it. Before the construction of the project, the safety production technical department shall, based on the actual conditions of the project, combine specific factors such as hydrology, geology, weather and climate, and seasonal changes at the construction site, formulate a practical and safe construction organization design, and pass the technical person in charge of the unit. Only after reviewing and approving can it be implemented. In the construction process, it is necessary to make corresponding adjustments and improvements according to the special circumstances of the project.

In addition, large-scale group projects or complex structures of key projects, among which highly specialized projects, include: deep foundation pit support, high clearance scaffolding, formwork support, lifting and lifting operations, etc. The construction organization is designed and supervised according to the design during the implementation process to prevent it from happening. OOO two years, Nanjing television studio hall roof, production design construction organization for security is not tight, the project manager lightly, eventually leading to instability due to the support template, pouring concrete at the time of the collapse, resulting in serious accidents.

2, engineering safety technology tests,

Prior to the commencement of construction of the project, the project engineer shall submit the construction specifics of the project, construction methods and safety technical measures of the sub-projects to the responsible persons, foremen and employees of the construction project to provide safety and technical disclosure. Before the start of each sub-project, the project engineer It is necessary to carry out the safety technical disclosure of a single project. The safety record should have a record of the account, and the date of signature and submission of both parties.

3 , pre-post training and education of construction workers:

All personnel participating in the construction must go through the three-level safety education and then go on duty. After the special operators must be trained and qualified by the right department, they can only hold the certificate.

With the above several software assurance measures, the safety production supervision and management personnel must focus on the following hardware aspects to check on the key points of safe production of construction projects: whether the erection of the scaffold complies with the specifications, and whether the temporary power supply on site is safe and reliable. Whether the type of construction machinery and equipment is sensitive and effective, whether the use of safety three pieces of treasure, the protection of four or five edges, and the implementation of the above measures can effectively prevent the occurrence of four major injuries in the construction industry (falling from high altitude, objects Strikes, electric shocks, and mechanical damage.

First, the scaffolding project:

Scaffolding erection requirements:

1 , pole: In addition to the top layer can be overlapped, the rest of the joints must be connected with docking fasteners, docking fasteners should be cross-arranged, adjacent pole joints can not be located in the same synchronization within the staggered distance of not less than 500MM , pole The lap length is not less than 1M and no less than two fasteners are fixed. The horizontal distance of the pole is between 1.05 - 1.3M , and the vertical distance is between 1.5 - 1.8M .

2 , horizontal bar (large bar):

Longitudinal horizontal rods should be set inside the vertical rods. Their length should not be less than 3 spans. They can be overlapped or docked. When overlapped, the overlap length is not less than 1M . Three rotary fasteners are fixed at equal intervals . When docking, the joints cannot be set. In the same span, the horizontal horizontal bar (small bar) should be set on the lower side of the vertical horizontal bar. The horizontal bar must be set at the main node. It should be fastened with right angle fasteners. The external extension on one side of the wall is not Above 500MM , the small crossbar of the working layer should be set at equal distances and not more than 1/2 of the longitudinal distance , ie about 900MM .

3 , scissors support:

Each channel bridging across the width of the pole root 5-7 preferably, not less than 6 m, and the inclination of the swash ground rod 45 degrees - 60 degrees between the scaffold must each have an outer side surface of bridging across the The distance between the middle scissor stays is not more than 15M . The scissor stays should be lapped, and the length should be no less than 1M . No less than 2 rotating clasps should be fixed. The scissors must be synchronized with the vertical pole and horizontal pole. Overlap, its lower end must be supported on the backing plate.

4 , lateral bracing

Scaffolding lateral bracings with a height of 24 M or more shall be provided at least once every 6 spans, one end at each end, and in the same section, the bottom to the top shall be arranged in a zigzag pattern.

5 , with walls:

Scaffold wall attachment is an important guarantee for preventing the scaffold from destabilizing. It can use flexible pull knots and rigid pull knots. The flexible pull joints are used to embed reinforcing steel rings in the building structure, and use small cross bars to hold the wall surface, and in the pole. near the intersection with the small bar with steel reinforcement ring around the live pole tie form a Rachel a supporting, stretch the wire should be more 4MM strandentwining, 2 shares not less taut flexible connector generally only Can be used on scaffolds up to 25M in height . Steel tensile knots: generally use rigid connecting rods consisting of steel pipes and fasteners. In the window openings or masts, steel pipes and fasteners are used to pull knots. The number of fasteners should not be less than 2 , and the area covered by each wall component should be less than 40M2 with vertical spacing within 3 steps and horizontal step within 3 vertical lines.

6 , the requirements of the scaffolding laying:

The construction operation floor shall be full of scaffolding boards, and wood boards, bamboo boards, etc. shall be used. Both ends of the scaffold board shall be fixed with horizontal crossbars. The joint length shall not be greater than 150mm .

II: temporary use of electricity on site

Electric shock injuries are one of the four major injuries in the construction industry. Therefore, the safety of electricity for construction sites is related to the survival of each construction company.

"Construction site temporary electrical safety specifications" The ministry standard (JGJ46 - 88) requirement that the preparation should be a temporary construction site construction design power, which should include: determining the power line, the distribution chamber, with a total The setting of the electrical box, distribution box, and the direction of the line, selection of transformer capacity, cross-section of the conductors, specifications and types of electrical appliances, drawing of electrical floor plans and wiring system diagrams, and development of technical measures for safe electrical use and electrical fire prevention measures.

1 , external protection

Outside the construction site must be kept safe operating distance between the edge and foreign overhead lines, 1KV the following 4M, 1 - 10KV 　 6M , 35KV - 110KV 　 8M .

Any part of the tower crane and the overhead line below 10KV or the minimum horizontal distance shall not be less than 2M .

2 , grounding and zero protection

Grounding: The grounding wire for electrical equipment is connected to the grounding body and is called grounding.

Zero: The connection between the electrical equipment and the neutral wire is called zeroing.

Grounding is divided into working ground, protective grounding, and repeated grounding.

Protective grounding: metal housing of electrical equipment and metal frame grounding of mechanical equipment.

Working zero line: The zero line that the electrical equipment leads because of running needs, is called working zero line.

Protection neutral line: It is led by the working ground or the zero line of the power distribution room or the zero line of the power protection side of the first stage leakage protector. It is specifically used to connect the conductors of the normal uncharged conductive part of the electrical equipment and is called the special protection neutral line.

The wiring system that separates the protection neutral line from the working neutral line is called the TN - S system.

(JGJ46 - 88) "construction site temporary electrical safety technical specifications" requirements, the construction site must be TN - S system then zero, i.e., three-phase five-wire system, the zero line and the protection line to distinguish zero.

The role and requirements of three-phase five-wire system

1 , to prevent the TN - C three-phase four-wire zero protection under the circumstances, due to sharing the work of the zero line and make it charged, resulting in electric shock accidents.

2 , to prevent mixing: PE yellow / green two-color special line dedicated equipment shell and the protection of the box outside the zero line, are not allowed to work for the zero line and phase line.

Erection requirements

( 1 ) The protection of the neutral line is strictly prohibited by any switches and fuses.

( 2 ), the protection of the zero line as a special line for zero protection, can not be used, the cable must use five core cable.

( 3 ) The protection neutral line must not be electrically connected to the working neutral line anywhere except from the working ground line (transformer) or the neutral line on the power supply side of the main distribution box.

( 4 ), repeated grounding must be on the protection of the zero line, the work of zero line can not be repeated grounding.

( 5 ) In addition to repeated grounding at the main distribution box, the protective neutral line must be grounded repeatedly at the middle and end of the distribution line.

The common problem of three-phase five-wire wiring system

( 1 ) Grounding

( 2 ), zero ground mixing

( 3 ), without five core lines

( 4 ) insufficient attention to grounding resistance testing

3 , three power distribution, two levels of protection

Three-level power distribution: total distribution box, distribution box, switch box, power distribution and lighting distribution should be set separately

Two-level protection: The distribution box and the switch box must be protected by a leakage protection switch.

Total distribution box electrical configuration

The total distribution box shall be equipped with the main isolation switch and the branching isolation switch, the main fuse and the shunt fuse (or the total automatic switch and the shunt automatic switch). In addition, the voltmeter shall be installed, the total ammeter and the total power. Table and so on.

Distribution distribution box electrical configuration

If there is a leakage protection device installed in the main distribution box, a leakage protection device must be provided in the distribution box, and the isolation box and the fuse should be installed in the distribution box.

Switch box configuration

Each electrical equipment should have its own dedicated distribution box. It must implement one machine, one box, one leakage protection and one brake system. It is forbidden to use the same switch box to control two or more electrical equipment (including sockets).

Three: Construction Machinery Equipment:

1 , tower cranes:

Focus on inspection of crane inspection reports, on-site inspection of various types of restrictions, limit devices and safety devices, tower crane operation, whether the commander holds valid certificates for jobs.

2 , gantry:

Focus on checking whether the installation of the frame is stable and reliable, whether the limit safety device is complete and effective, whether the brake is sensitive and reliable, whether the broken rope protection is effective, whether the cable wind rope must use a steel wire rope more than 9 mm , whether the safety door and the side file are used. Board, floor unloading platform protection is tight, lightning rod, grounding is reliable.

3 , small and medium-sized equipment:

Focus on checking whether all kinds of protective devices are complete and effective, and the operating status of the transmission part, whether there is grounding, zero protection, etc.

Fourth, safety three pieces of treasure, hole, border protection

Correct use of safety three pieces of treasure, must enter the construction site to wear a helmet correctly

The role of the safety net: to prevent people and objects from falling, or to avoid reducing the impact of falling and objects, safety nets are divided into flat nets, vertical nets and dense mesh safety nets. At present, the use of dense-mesh safety is widely used in the Dongtai region. The standard of the dense mesh safety net: There are 2000 mesh nets in the 100 square centimeter area , and the penetration test is carried out. The angle between the net and the ground is 30 degrees, and the 5 kg φ 48MM steel pipe is free to fall at a height of 3 meters. through.

The use of safety belts to prevent accidental fall of high-altitude workers, should be used with high hanging low, not allowed to tie the use of the rope, the hook should not be hung directly on the rope, should be hung on the connecting ring.

Hole edge protection: opening, stairway, elevator wellhead, derrick access

Edge: The face of the construction site without enclosing facilities is called the edge. It mainly includes the stairs, the floor, the roof, the balcony, the material platform, the picking platform, and the provocation.

Hole, striking the limb to be provided at the guard railing, by the upper and lower rail and baluster two compositions, the height from the ground bar 1.0 - 1.2 m, the height from the ground bar 0.5 - 0.6 m.