1. Types of common accidents of scaffolding
From the erection, use and dismantling process of scaffolding, there are mainly the following accidents:
1. The scaffold is unstable as a whole, causing the whole scaffold to collapse vertically
2. The scaffold is not erected according to the regulations and standards, causing the whole scaffold to fall outward or inward, or even partially collapse.
3. Due to incomplete protective facilities, the operator falls from the scaffold.
4, improper construction organization, resulting in falling objects from high altitude.
5. Accidents caused by various unexpected factors.
second, analysis of the causes of scaffolding accidents
(a) direct causes
1. unqualified materials. At present, in order to seize the market, many steel pipe manufacturers compete with each other to adopt the means of low-price competition. The wall thickness of steel pipes produced is mostly 2.8-3.2mm, but when settling accounts with users, they are still calculated according to the quality of steel pipes with a wall thickness of 3.5mm stipulated in the standard, resulting in the actual weight of steel pipes supplied per t of only 84-92kg. The inertia moment loss of this kind of steel pipe is about 1%. After years of construction and use, the wall thickness is reduced due to corrosion of the steel pipe, and its inertia moment is smaller, which has potential safety hazards.
2. We don't pay attention to the design of scaffolding construction scheme, and we still build scaffolding for some special purposes according to experience, which leads to unreasonable scaffolding structure and reduced bearing capacity.
3. We don't pay attention to the setting of the wall-connected parts of scaffolding, or the number of wall-connected parts in the irregular part of the building facade is insufficient, or we dismantle the wall-connected parts at will during use and fail to restore them in time.
4. In order to seize the construction period and catch up with the progress, multiple layers are operated at the same time, resulting in serious overload of the whole frame or excessive stacking of scaffolding, resulting in local overload.
5. Sudden natural factors and external factors, such as strong wind and violent mechanical collision.
6. Uneven settlement of foundation
7. Safety protection facilities are not set in the operation layer as required. For example, the outer vertical net and the inner interlayer net are not set as required.
8. The frame surface is not laid as required, the gap is too large, or the scaffold board is unstable, poorly fixed and broken after loading.
9. The shelf surface is narrow, there is too much stacking, and the workers are crowded and collided.
1. When carrying and installing heavy objects, the body is unbalanced and slides down due to excessive force and smooth frame surface.
11. The steel pipe scaffold is erected within the safe distance of high-voltage and overhead lines, resulting in electric shock casualties.
12. The scaffold erected in the open area or the scaffold higher than the adjacent buildings is not equipped with lightning protection facilities, resulting in lightning casualties.
13. Failure to dismantle the scaffold as required will cause the whole scaffold to collapse or local collapse; Or throw the removed materials from a height, causing falling objects to hurt people and objects to hit accidents.
(II) Indirect causes
There are two main indirect causes of accidents. First, safety management is not in place; Second, workers have poor awareness of safety protection. Although they are indirect causes of accidents, they are important factors leading to direct causes and must be paid attention to.
III. Safety management measures for scaffolding
Scaffolding work belongs to aerial work, which is dangerous, and the whole project must be assisted by scaffolding. Scaffolding is a temporary facility in building engineering, but it is related to the safety management and progress of the whole project. In order to ensure the construction safety, there are strict requirements on the material specifications, quality and erection requirements of scaffolding. Strengthening the management of scaffolding is the top priority in safety management.
(1) Scaffolding materials are standardized and strictly controlled
In order to ensure the safety of scaffolding in use, the project department strictly controls the procurement and use of scaffolding materials. Scaffolding materials can only be used after they have been uniformly accepted by the Ministry of Security, the Quality Department and the user department. Shelf tube adopts all φ48.3×3.6 steel pipes specified in the new standard, and any bent, squashed, cracked or severely corroded steel pipe is strictly prohibited. Fasteners are made of malleable cast iron, and their materials shall conform to the provisions of the current national standard "steel tube scaffold couplers" (GB15831), and must have the factory certificate. Brittle cracking, deformation or slippery threads are strictly prohibited. Scaffolding mainly uses bamboo scaffolding and rigid scaffolding. The thickness of the scaffold board must be greater than 5cm, the bolt hole shall not be greater than 1mm, and the bolts must be tightened. The length of the bamboo scaffold board is unified to 2.3m and the width is 4cm. It is strictly prohibited to use any decayed, twisted or broken scaffold board. Steel scaffolding shall be made of A3 steel plate with a thickness of 3mm, with a length of 2.56m, a width of 25cm and a rib height of 5cm. There should be connecting devices at both ends of the board, and there should be anti-slip holes on the board surface. Any crack or distortion shall not be used.
(2) standardize scaffold erection process to ensure that scaffold erection is firm and qualified
strengthen monitoring during scaffold erection to prevent irregular scaffold erection and local instability or collapse. When scaffolding is erected, the length of scaffolding pipe must be selected according to the erection height, and the butt joints must be staggered and not stay in the same span, and the joints are connected as a whole with butt fasteners. It is forbidden to use rotary fasteners for scaffolding docking. All longitudinal and transverse frame beams are provided with bracing and splayed bracing. At the corner of the shelf, the scaffolding should be staggered. Scaffolding should be laid smoothly and each piece should be tied firmly. Uneven places should be padded with wooden boards and nailed firmly, and brick mats are not allowed. Scaffolding must be laid vertically and horizontally on the wall surface, and fully spread in place, leaving no space. Effective protective measures must be taken at the place where it is not fully spread. Scaffolding board must be tied with l8# lead wire in parallel, not less than 4 o'clock, which requires firm binding and smooth junction. Scaffolding board should be intact when laying, and it should be replaced in time if it is found to be damaged. When turning scaffolding on the shelf, two people should do it from the inside out in order, and a safety net should be set below. Suspended scaffold should be fixed on a solid part of the structure. Suspended steel pipe hanging scaffold should have two-way insurance in the erection process. In addition to the fasteners of the column and crossbar, an insurance fastener should be added at the upper and lower ends of the vertical rod, and the length of both ends of the vertical rod extending out of the crossbar should not be less than 2cm. Dismantling scaffolding should be carried out from top to bottom. It is forbidden to work up and down at the same time or push down the scaffolding as a whole. Before the full-house scaffold is erected, the erection scheme shall be approved by the technical director of the construction unit and the chief supervision engineer of the supervision unit. Scaffolding should be signed and listed by the construction and use departments after erection, and should be delivered for use. When scaffolding is delivered for use, there should be written disclosure in terms of technology and safety. In use, it should be inspected and maintained frequently, and the inspection should be strengthened after strong winds and heavy rains. Scaffolds that have been stopped for a long time can only be used after being inspected and identified before returning to use. The error of the vertical pole, the distance between the large and small cross bars and the height of each step of the scaffold should be controlled within the allowable error range of the specification.
(III) Preventing unsafe behaviors of people
In project design, scaffolding construction cannot be completed by experience, and strict design and calculation must be carried out, and construction management personnel should master its technology and construction requirements to ensure safety. Establish and improve the project safety management organization, send full-time safety production management personnel to carry out safety management, clarify the responsibilities of safety management personnel, improve the safety awareness of management personnel, improve the preparation ability of safety prevention technical measures of safety management personnel, and improve the emergency ability of safety management personnel to deal with safety accidents. Formulate targeted and feasible scaffold erection and dismantling schemes, and strictly carry out safety technical disclosure. The safety protection scheme is a document that specifies how to carry out safety protection on the construction site. Therefore, it must be compiled according to the actual situation of the construction site, the construction environment, construction methods and staffing on the site, and in accordance with the provisions of standards and norms, effective protective measures are determined, which are carefully implemented in the actual work of the project.
strengthen the training and education of construction personnel, improve safety awareness, enhance self-protection ability, and put an end to illegal operations. When erecting and dismantling scaffolding, the operators should hang up their safety belts, and the operators of poles and poles should cooperate closely. Red and white belts or warning signs should be set around the construction, and they should be supervised by special personnel. Irrelevant personnel are strictly prohibited from entering. Scaffolding erection personnel belong to special operations, and they should receive professional training and obtain effective special operation certificates before they can work independently with certificates. It is forbidden to operate without certificates. "Three-level safety education" should be given to the new workers entering the site, and special operators need to undergo special training and pass the examination before taking up their posts. Safety technical disclosure should not stay in oral form, and mutual care among colleagues is even more difficult to replace formal disclosure. Safety education and training should be implemented, and the safety awareness of construction personnel should be improved, so as to change "ignorance" into "wisdom" and "fearlessness" into "promising".
in a word, scaffolding number is a temporary facility in construction, but it is related to the construction safety and progress of the whole project. It is an indispensable framework in the implementation of the project and the place where major safety accidents are most likely to occur in the construction process. Therefore, in the construction safety management, the safety management of scaffolding is particularly important.
In the face of the frequent occurrence of scaffolding safety accidents in recent years, the Ministry of Housing and Urban-Rural Development and relevant departments have stepped up the supervision of construction safety, and successively issued a series of policies and regulations on safe construction. At present, the situation of construction safety in China has greatly improved. "It is not enough to ensure safety for a thousand days, and there is more than one day of accidents." Only when the safety alarm bell rings among all kinds of management and construction personnel can we not hurt ourselves, others and others in the construction; Only by extensively strengthening safety education, constantly improving safety awareness, mobilizing the enthusiasm, initiative and creativity of all staff to participate in safety management, and taking effective pre-control measures, can we gradually reduce or avoid the occurrence of malignant accidents caused by scaffolding deaths and injuries.
The safety management of scaffolding needs a process of "knowing-practicing-knowing-practicing again". Only by constantly exploring and summing up experience can it serve the construction industry more safely, reliably and economically.
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