Prevention of scaffold accidents in the hottest co

Construction site scaffold accident prevention

construction site scaffold is both a construction facility and a safety facility, with large quantities and large investment. Scaffolding is often the first thing you see when you enter a construction site, so scaffolding also represents the image of the site. Scaffolding is a key facility, which should not be underestimated, and we must do our best. This paper discusses the possible accidents and their prevention in the process of assembly, disassembly and use of scaffolding as a safety facility, and also discusses the safety of concrete formwork erected by steel pipes

I. erection accident

special attention should be paid to whether there are transmission lines, especially high-voltage lines, outside or above the shelf. Now in general cities, steel pipes have replaced bamboo or wood for scaffolding, and iron steel pipes are good conductors. There have been many accidents in Ningbo where steel pipes in the hands of scaffolders hit high-voltage lines, and scaffolders were either killed or seriously injured. There are also cases where the steel pipe accidentally fell down and accidentally connected to the high-voltage line below, resulting in a short-circuit trip of the high-voltage line

it is very dangerous for the steel pipe to fall from a high place. If it hits the person below, the steel pipe will fall from a certain height. Whether he or she wears a helmet or not, it will generally cause death. In August, 2001, a steel pipe slipped from the roof and killed the workers below at the construction site of Ningbo University

the second thing to pay attention to is the stability of the scaffold during erection. Especially for some special frames, for example, when a well frame serves two buildings, a corridor should be set up between the two buildings. This kind of aisle shelf is narrow, but very high. The project is a six story building, which is six stories high, and the project is an eight story building, which is eight stories high. There should be calculations and construction plans. There is also a high floor cast-in-place concrete formwork support frame. In October 2000, a vicious accident occurred in Nanjing, in which the cast-in-place concrete formwork supporting steel pipe frame of the television studio project collapsed, killing 12 people

another kind of thing is easy to happen on the bamboo scaffold. There is such an accident in Ningbo. The bamboo scaffold has been built to the sixth floor. At that time, the scaffold tilted inward, and the scaffolder took a pole and supported it on the brick wall just built on the sixth floor, one person high, to the outside. As a result, the new brick wall collapsed inward, breaking the floor perforated plate, and the broken perforated plate fell down layer by layer, until the bottom layer, killing the second migrant workers on the bottom layer

scaffolders often have to erect a well shaped frame. At this time, pay attention to the stability of the frame and tension the cable and wind rope as required. Or make the connection between the frame and the wall

II. Demolition accident

pay attention to the high-voltage line as well as the careless fall of steel pipes and instability as the erection. However, it should be pointed out that the instability caused the collapse of the frame. In January 2000, a 20 storey building project in Ningbo has been done for more than two years, and it ended immediately. At that time, the frame was being demolished, and the frame was also demolished to a small part of the northeast corner, about 67 meters wide and 10 meters high. In another hour or two, the frame was also demolished. But the accident happened at this time. The reason is that such a high shelf was dismantled and only four steel pipes on the top were connected to the wall. At the time of the accident, two of the four steel pipes were removed, and the frame eventually collapsed due to instability, killing one person and seriously injuring the other

the support of scaffold and wall (now hard support is required to ensure that it can not only bear the equipment with the thrust travel range scattered below 400mm, but also support the tension, not the previous iron wire, which does not support the thrust) should be set up in sufficient quantity according to the regulations. The current situation is that as soon as some construction sites arrive at the painting stage, many supports are removed, and the hidden danger of accidents comes. Two such accidents occurred in Ningbo last year, and the bamboo scaffolds at two construction sites collapsed

in the treatment after collapse, the steel pipe frame is more difficult than the bamboo frame. The bamboo can be cut with a knife and saws to make a way to save the people who are pressed inside. The steel pipe treatment is much more difficult, especially when a large area of formwork support frame collapses. If people are pressed in the middle, this situation occurs in the Nanjing TV building accident mentioned above. Therefore, special attention should be paid to the stress calculation of the steel pipe rack, and attention should be paid to the sufficient support with the wall to prevent collapse accidents

III. accidents of lax scaffold protection

the feed inlet of construction elevator and well frame includes the feed walkway and the protective door of the feed inlet. These parts are often handled by scaffolders, which should be done well. In Ningbo, there were accidents in which people died due to unstable feeding openings

the scaffold enclosure should be tightly hung, which can prevent people from being injured by falling bricks, steel pipes and reinforcing bars, and also prevent people from being injured by electric shock caused by the transmission line, especially the high-voltage line, when the steel pipe is delivered outside the printer that prints small tickets in the shelf similar to the supermarket

some reserved openings at the elevator wellhead are often built by scaffolders, which should also be done well

IV. formwork support accident as formwork support

now the floor is generally cast-in-place, and formwork support has become very important, especially the bottom of the ground floor, such as shopping malls, is 34 meters or even 56 meters high, and the second floor, such as shopping malls, is still loaded with building slab thickness, so the requirements for formwork support below are also high when pouring concrete. If the support such as steel pipe or wood is not designed and the strength is insufficient, especially the horizontal connecting rod or diagonal support considering instability is insufficient, and the stability calculation cannot meet the requirements, an accident may occur

there have been four major accidents of formwork collapse, which are respectively in October 2000 in Nanjing, a television studio hall. The experimental speed of different springs pouring concrete is basically the following: compression spring: 200mm/min; Lockable spring: 200mm/min; Rigid locking: 2mm/min; Elastic locking: 8mm/min formwork support frame collapsed, resulting in 6 deaths; In July 2002, the concrete formwork support of an activity center building of Zhejiang University collapsed, causing 3 deaths; In February 2003, the Ultra-high Steel Pipe Formwork of the 24 meter square and 28 meter high PHS plant of UT Starcom in Hangzhou collapsed, resulting in a catastrophic accident in which three people died in general, and in March of the same year, the formwork of a plant in Youngor, Ningbo collapsed to two people

if the concrete formwork support is above a certain load or a certain height, it can be considered to replace the steel pipe formwork with section steel, or when the concrete is too thick, it can be considered to pour and vibrate in layers, and then pour a layer of concrete after the concrete poured in the first layer reaches the strength, so as to share the weight of the upper layer of concrete with one layer of reinforced concrete, so as to reduce the load of the formwork support. The formwork support of the concrete floor slab of a high-rise building in Ningbo with a thickness of more than 2 meters adopts the method of pouring and tamping in two layers. Of course, this should be contacted with the design unit

v. scaffold steel pipe hoisting and loading and unloading accidents

tower crane hoisting steel pipes mainly need to be tied firmly and hoisted stably. When hoisting, what things should be hung and pulled, and what things should be bumped during hoisting. When hoisting in place, pay special attention to whether there are people below. If the tower crane arm is not long enough to send in place, it is not allowed to push and pull the people below in place

there was a construction site in Ningbo, where a steel pipe fell off and stabbed a car on the road because the steel pipe was not tied firmly. Fortunately, there were no casualties

in case of transportation, loading and unloading accidents, especially during unloading, it is necessary to prevent the steel pipes full of vehicles from rolling down and hitting people, and pay attention to safety during steel pipe loading and unloading

during transportation, pay attention to the loose binding of steel pipes, falling and hitting passers-by, steel pipes, bamboo, etc. if they are too long and stretch out of the trunk, their ends should be hung with eye-catching red cloth, etc,. Be careful when driving to prevent sudden braking and accidents caused by rear collision

VI. shelf fire prevention

mainly bamboo shelves. On October 24, 2000, at the construction site of Ningbo Zhenhai post and telecommunications building, because someone burned electric welding on the outer wall of the 10th floor, the molten iron fell on the bamboo scaffold on the sixth floor. After a period of time, it finally burst into a fire. When the people on the tower crane found that there was no way to put out the fire. The fire burned out the bamboo shelves on the whole 12 floors in 30 minutes, causing a loss of 200000 yuan and a delay of 2 months

when the wooden workshop and kitchen are connected with or close to the shelf, the fire in these places may affect the shelf. Therefore, the kitchen of the carpentry room should be separated from the shelf by a safe distance (such as 6 meters)

VII. Other accident prevention that scaffolders should pay attention to

don't climb high after drinking, don't wear slippers to work, and don't engage in scaffolding work with heart disease; Safety helmets shall be worn when entering the construction site, safety belts shall be worn when erecting shelves and cross frames, scaffolders shall bring tool bags, and objects such as steel pipes shall not be thrown down when erecting and dismantling shelves

scaffolders should also pay attention to the prevention of some common accidents on other construction sites, such as preventing electric shock. If scaffolders do not know electrical knowledge, they should also pull wires and connect electric lights on the construction site or in the dormitory; If there is a river near the construction site, especially in summer, pay attention to swimming and bathing to cause drowning accidents

VIII. Scaffold design

steel pipe scaffolds with a height of more than 30 meters, or with cantilever structures, or super high (such as more than 3.5 meters) and overweight, such as concrete beam and slab thickness of more than 0.6 meters, concrete formwork and other shelves that may be overloaded should be designed

the design will not be carried out here. You can refer to JGJ safety technical code for fastener type steel pipe scaffold in building construction