Fire Risk Analysis And Evaluation Of Colorful Steel Buildings In Lanzhou City

Color steel plate building is a kind of building with steel plate as the skeleton and sandwich plate as the wall panel.Because of its convenient,quick and efficient assembly and disassembly,it has become the first choice for temporary buildings.In recent years,due to the increasing demand for urban housing,the sharp rise in land rent and the impact of urbanization,color steel plate buildings are widely used in the construction of urban villages,urban and rural junction and urban industrial parks.However,the material of color steel plate building leads to its problems such as extremely low ignition point,rapid spread after combustion,rapid collapse and toxic gas emission,thus becoming an important hidden danger of urban fire.At present,the research on the color steel building mainly focuses on the small-scale illegal reconstruction in the city,the flammability of the material and individual fire cases,but the research on the relationship between the color steel building and the urban spatial structure,the regional fire risk and the fire rescue measures in high risk areas is obviously insufficient.Based on the comprehensive evaluation of the relationship between the urban color steel building group and the urban spatial structure,it is of great significance to study the fire risk of the color steel building and the optimization of the fire rescue structure for the urban development and construction planning.Based on this,this paper takes Lanzhou city as research area,the integrated use of GIS spatial analysis method,etc.,in the "location-allocation" model study of Lanzhou city big or small choi steel,the relationship between buildings and urban space structure analysis of the regional characteristics and classification of fire risk level,and based on this,advances the new city fire protection construction plan.The main work of this paper is as follows:(1)Study on the relationship between color steel plate building and urban spatial structure.Firstly,the spatial and temporal distribution and aggregation characteristics of different types of colored steel plate buildings were studied by using kernel density and buffer analysis methods.Then,the correlation analysis with urban economic and social factors is carried out.The experimental results show that:(1)More than 70% of the large colored steel buildings are distributed in the 600-meter buffer zone of the company,and more than 70% of the small colored steel buildings are distributed in the 1000-meter buffer zone of the school;(2)The number of large colored steel plates in industrial parks is increasing,which indicates that the urbanization process is accelerating and the economic growth is obvious.(3)The large number of small colored steel plate buildings indicates that the urban villages are in the stage of population concentration and rapid structural transformation,which accelerates the rural-urban transformation.(2)Analysis of spatial coupling characteristics of color steel plate building and POI point and fire point.In view of the particularity of the geographical location of the color steel building group and the inadequacy of the comprehensive application of POI and fire Point in the study of urban fire risk.This paper selects multi-source data,uses kernel density analysis and superposition analysis method to divide the grid,and analyzes the spatial coupling relationship between the data with the help of two-factor cartography.On this basis,the urban fire risk in different coupling regions is compared and analyzed.The results show that:(1)The color steel plate buildings,POI and fire sites in Lanzhou present a high spatial coupling state,and they have a strong spatial correlation;(2)The urban color steel plate buildings with significantly higher density than POI in urban villages,industrial parks and other areas are the areas with higher fire risk level.(3)Optimize the spatial layout of fire stations.Firstly,based on the data of color steel buildings,POI and urban fire,the fire risk levels in the study area were classified by the methods of kernel density analysis and correlation calculation.Secondly,the simulation operation is carried out by means of the "position-allocation" model and the optimization objective.The experimental results show that:(1)There are large scale colored steel plate buildings in urban villages and urban and rural junctures in Lanzhou,which are prone to frequent fires and difficult to rescue.(2)High fire incidence areas in Lanzhou are mainly distributed in Liujiapu Street,Jiannan Road Street,Gaolan Road Street and other areas.(3)The fire protection coverage rate of the existing fire stations is 26.19% within 5 minutes of rescue time,and the coverage rate of high-risk fire areas is 44.41%.After calculation,it is finally determined that at least 14 more fire stations are needed to meet the current optimization target.After optimization and adjustment,each index has been greatly improved,which can meet the fire rescue needs of the region at the present stage.