Study On Rapid Assessment Method For Structural Safety During Firefighting And Fire Rescue

Due to the influence of fire and high temperature,the material properties of the building components will deteriorate and even cause serious deformation.Not only will the bearing capacity and durability of the building be relatively reduced,but also the safety of the whole structure will be rapidly decreased in a short time.At present,in terms of practical applications,there's a relatively high level of research on structural safety after the fire,but the structural safety assessment of firefighting and fire fighting has been reduced to a lot of research,so it's important for the safety and the safety of the fire and the fire,the people who are trapped in the fire,the safety and he safety of the people in the field,that's the important application of structural damage assessment and safety assessment.In this paper,from the three elements of the fire burning and its development of research on high temperature fire on the direct and indirect effects of building component performance,and analysis of steel structure and reinforced concrete structure and brick structure bearing capacity and durability of the components are reflected in the fire as well as the deformation degree,with quantitative analysis and the method of combining theory analysis,summed up a set of countermeasures and methods of practical value for the fire fighting and fire rescue during the security to provide decision basis for building structure,and selected the typical fire cases of countermeasures proposed methods.The main rapid assessment steps,methods and conclusions are as follows:(1)The rapid survey of fire fields should be collected by the person in charge of the unit,the fire discoverer and the fire fighters.The concrete general situation of the building,the cause of the fire,the fire and so on are determined,and the data in the fire disaster assessment report provided by the fire department are analyzed,and the scene after the fire is carried out.The observation records and photographic records are used as reference basis to judge the characteristics of the whole process of the fire,determine the location of the heavy disaster areas and the damaged centers,and handle the safety of the members still in the dangerous state.In order to quickly determine the temperature of the fire field,in accordance with the current fire extinguishing procedure,the fire often comes into the peak period from the fire alarm to the fire officers and soldiers to the fire field.From the burning form and the burning nature,it can be preliminarily deduced that the temperature of the interior is rising rapidly because of the full combustion of the combustibles,so that the fire temperature is close to or reached the highest.The temperature can reach 800-1000 degrees in local or whole area.(2)Rapid assessment of the structure safety during fire extinguishing.When the fire occurs,the building components will deteriorate the material performance seriously under the effect of high temperature.The internal forces inside the structure will be redistributed,which will weaken the bearing capacity of the structure rapidly and produce obvious structural deformation,which will jeopardize the stability of the structure and cause local damage to the structure.Bad or even cause overall collapse;the risk of collapse in steel structure.When the fire temperature is high,the risk of collapse will occur if the steel structure exists or occurs below.(3)Combined with the analysis and investigation results of fire field,put forward mild,moderate,severe and dangerous four criteria for safety evaluation.The main structure of the building is not distorted or bent.The depth of damage is between 10 and 15mm,Shrinkage cracks occur on the main wall,but no cracks are formed,is mild;When the damage depth of building structure is between 15 and 20mm,the main body of the building has 0.3 to 1mm cracks,is moderate;The main damage degree is 2-4 times the limit deflection,and the crack is above 1mm,is severe;The damage degree is 4 times the limit deflection,and the crack is above 5mm,which is dangerous damage,is dangerous.(4)When the time of fire extinguishing is quickly determined,there are many catastrophe factors in the fire field.The judgment of the safety time for the safety of fire extinguishing should be derived from the fire resistance of the building itself.The accurate estimation of the time of fire extinguishing is an important way to protect the safety of the personnel inside and outside the fire field.Combined with the combustion performance of the main building components,a method for determining the minimum time value of fire safety through building fire resistance rating is proposed.Fire have great Act on Structural safety.After rapid assessment,comprehensive inspection and identification should be carried out,so as to provide scientific basis for subsequent transformation.