Disposal and rescue of collapse accident in construction

1. Preface

with the rapid development of China’s economic construction and urbanization in recent years, the city scale is expanding day by day, and there are more and more high-rise and special types of modern buildings. The huge differences between these buildings and traditional buildings in use function, building materials, structural form, space size, supporting facilities, personnel density and so on, bring a lot of problems to fire safety. Once an accident occurs, it is easy to cause mass casualties and huge losses. Among them, the probability of building collapse accidents increases sharply, and the disaster consequences are very serious, causing heavy casualties and property losses, which has brought adverse effects to the society. For example, the “9.11” incident in the United States, the collapse of the world trade center after the terrorist attacks, more than 300 firefighters and thousands of people buried in the building, shocked the world; The “11.3” catastrophic fire in Hengyang, Hunan Province, led to the collapse of residential buildings, which claimed the precious lives of 20 firefighters; 1n 2008, the “7.18” factory fire in Fengxian, Shanghai, collapsed the crossbeam of the factory building, resulting in three deaths and nine injuries to fire officers and soldiers. Therefore, we are seriously studying and mastering the basic causes and general laws of building collapse, analyzing its characteristics, studying and formulating Disposal Countermeasures, so as to serve our fire fighting and rescue work< Second, the basic causes of building collapse. First, the arbitrary construction in violation of the specifications. 1n engineering design, too much pursuit of economic benefits, in violation of the provisions of the national technical code for architectural design, arbitrarily reduce the design standard; During the construction, they did not follow the design and increased the building area and the number of floors without authorization. Some even built houses in violation of regulations without the consent of the planning department or the design department< (2) illegal operation and neglect of quality. 1n order to seek self-interest, the construction unit cut corners and changed beams and columns. 1t did not strictly control the selection of engineering materials and purchase channels. 1t used unqualified raw materials and did "black heart project" and "bean curd residue project" without conscience< (3) lack of management and potential risks. Change the building structure and plane layout without authorization, dismantle the internal load-bearing structure of the building without permission, so that the building structure has uneven load-bearing and uneven stress; Changing the use and function of the building without authorization, the building can not meet the new functional requirements of the right to use, and becomes a dangerous building; The second decoration is not in accordance with the code for fire protection design of interior decoration of buildings, and the requirements of the use nature of buildings are ignored, which increases the fire load in buildings< (4) fire and burning, causing damage. The surface of wood structure is ablated, which weakens the load section and makes the load-bearing structure unbearable; When the steel structure is heated, plastic deformation occurs. About 15 minutes after the fire, the bearing parts become soft and lose the bearing capacity; After the high temperature action of masonry wall, the internal material is deformed and loose due to heat; When the prestressed reinforced concrete structure is heated, it loses the pre stress and reduces the bearing capacity of the structure. 1n addition, under the high temperature conditions of fire, the mechanical properties of building materials have changed greatly, as well as the impact and vibration caused by the explosion inside the building, the impact of water flow during fire fighting, and the sudden cooling of high heat building components< Thirdly, the main characteristics of building collapse accidents are as follows: (1) it is very sudden and difficult for people to escape. Affected by natural or human factors, building collapse accidents may occur at any time, and the precursor of the accident is not obvious, and the time for people to escape is very short. This kind of suddenness makes people unable to escape in time, which easily causes a large number of casualties< (2) facilities are damaged, which is easy to cause secondary disasters. Sudden building collapse accidents may cause the destruction of gas, power supply and other facilities inside the building, and lead to the occurrence of fire, especially the collapse of chemical plants and other structures. 1t is very easy to form a chain reaction, leading to the leakage of toxic gas (liquid) and explosion and combustion accidents< (3) heavy casualties and great social impact. The destructive collapse of buildings has caused heavy casualties, which has a great negative impact on society. The dam collapse of Vialli reservoir in October 1963 in 1taly, the man-made explosion in Shijiazhuang in 2001, the "9.11" incident in the United States, the collapse of gantry tower crane in Shanghai China shipbuilding factory in 2001, the collapse of tower crane in Shanghai section of Beijing Shanghai high speed railway in 2009, the "building collapse" incident in Shanghai The collapse of a bridge in Rajasthan, 1ndia, has caused panic to society and even the whole world< (4) the rescue is difficult and the operation time is long. Once a large building collapse accident or earthquake and other natural factors cause a large area of building collapse, often lead to more casualties, and disasters, rescue is very difficult. 1t took four days for Hengyang fire rescue to dig out all the victims, which requires all the rescue workers to prepare for continuous operations. At the same time, rescue forces will involve public security, medical aid, water, gas, transportation and other departments; Due to the large number of trapped people and the limitation of equipment, the effectiveness of rescue operation will be weakened. Therefore, the post disaster rescue will be a long-term continuous operation< Four, the main characteristics and basic countermeasures of building collapse accident rescue work (1) the main characteristics 1. There are many participants in the war, and it is difficult to command and coordinate. After the building collapse accident, in addition to the public security fire forces, the local government, water supply, power supply, gas, public security, medical aid, local garrison and other units and departments need to be present to participate in the rescue operation. 1n addition, the leaders at the scene do not know much about the procedures and has the final say that anyone will command. And no one can command it, no one can count. 1t is difficult to form an effective integrated rescue command system because of unclear site identification, mixed personnel and unclear operational tasks of various functional departments. For the fire forces, it also involves commanding multiple squadrons to participate in the war

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