| Steel structure as the main form of contemporary architecture, more and more widely used, in particular, more prominent in the ultra-high- rise buildings and large public facilities, but the steel at high temperatures(fire) conditions exhibit poor fire its deadly the disadvantage in case of fire, it may cause local damage to steel buildings or whole collapse. Therefore, the fire protection of steel structures is of great significance, apply fire retardant coating steel fire as one of the most economical and practical way to get a lot of use in the actual project. In this paper, under the influence of different coating thickness on steel frame-based high temperature(fire), to find in favor of the measures and methods fireproof.This paper mainly do the following work:(1) the existing domestic and international research results are summarized, high temperature(fire) performance under different types of fire-resistant coating of steel were compared, obtained how to choose suitable for high temperature(fire) steel structure parameters and material properties of different kinds of fire retardant coating characteristics;(2) based at ISO-834 standard indoor fire temperature curve, when the ambient temperature reaches a certain condition, the coated steel frame based on different kinds of fire retardant coating on fire by changing the thickness of the coating, analyze changes and stress changes steel frame steel frame girder span deflection;(3) use different fire-resistant coating in the same steel frame, analyze the changes in stress and deflection span steel frame structure the impact;(4) analysis of different coating thickness, temperature field change of steel frame structures;(5) from the actual project, taking into account the use of fire retardant coating steel construction projects due to external causes loss of natural phenomena, the paper try to analyze the when the protective coating of steel half off after impact on the overall situation of steel frames.Analysis showed that:.(1) When steel frames without any fire protection, it will be significantly less than the carrying capacity have fire protection. When different types of fire-resistant coating, the overall trend is constantly on the rise as the temperature of the absolute value of the stress, deflection on the increase, but can also be found with increasing thickness of the coating, the change in trend gradually slowing;(2) when the outside temperature at 200 ℃ ~ 300 ℃, the effect of different coatings on its deflection is very small, when the temperature increases from 400 ℃ to 600 ℃, its deflection change began to accelerate in the same kind of other coating inside, the greater the thickness, the corresponding deflection changes also smaller;(3) the use of different types of fire retardant coating steel frame in the same time, with increasing temperature, coating thickness and edge column the greater the gap, the maximum and minimum normal stress normal stress of the absolute value of the more significant, therefore applying different fire-resistant coating in the same frame at the same time, the structure is not favorable, the actual construction process, the coating thickness had better be consistent;(4) in the frame beam the temperature field analysis found that with increasing time-retardant coating of thick coating curve rises more gentle, and the ultra-thin fireproof coatings curve rises rapidly.(5). When fire retardant coating steel frame intact, structural steel beams rise in temperature than the temperature of fire retardant coating steel beams falling to half rise slowly, reaching warming 3600 s, the integrity of the protective coating of steel girders off half the temperature rise of only fire-resistant coating 63%, 58% deflection off only half of fire retardant coating, described fire-resistant coating on the integrity of the fire resistance of structural deformation capacity enhancement played a role. |
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