The Safety Performance Analysis Of Reinforced Concrete Members After The Fire

If the building is on fire that will affect the life and property of people. At thesame time, it is also has great security threats to the buildings which in current use orready for use. Therefore, it is very important that an analysis of the building after thefire in identification reliability. The mechanical performance will be changed after thereinforced concrete members on fire. For example, there are two kinds ofreinforcement and concrete material strength and modulus of elasticity attenuation.And the material characters between the bonding and strength degradation. Mechanicalproperties change is related to the whole component section which causes bearingcapacity decline, thereby lowering the building structure system overall resistancelevel, and finally effect in structure or component reliability that can’t achieve therequirements.There are three parts of this paper in the analysis of the reliability after thereinforced concrete members on fire. There are respectively of fire temperature fieldsimulation, calculation of residual strength and reliability analysis. It’s can’t accuratelyfire building damage assessment until finishing these three parts. Moreover, it canprovide a reasonable theory for the program in subsequent maintenance. It is raisingthe level of resistance of structural members and security performance, and to cuttingdown economic losses as less as better.This paper, analyzes and summarizes reading carefully predecessors’achievements, and on the basis of fire engineering research on the present situation of apreliminary understanding and the understanding. 1. Analysis and consolidate the constitutive relationship of reinforced concreteafter fire. Due to fire in the occurrence, development and follow-up treatment, factorsaffecting large and complicated and ever-changing. Domestic and foreign scholar’sresults vary greatly in the study, but there are a lot of things in common, this article hasto be a reasonable screening, supported by different types of materials, the constitutiverelation of reinforced concrete with different cooling methods. For the next calculationand reliability analysis, which provide a relatively reliable support to the capacity ofmembers remaining.2. Further perfecting calculation method of residual strength after hightemperature of RC members. Mechanical properties of reinforced concrete memberafter fire their varying degrees of attenuation degradation, and geometry of the sectionwill be reduced. In this regard, this article of reasonable assumptions, and attempted tointroduce a tiered calculation method and the equivalent section reduced to remainingbearing capacity of reinforced concrete member after fire, improves the accuracy ofcalculations. A hierarchical method, for example calculates the different fire resistancereduction factor of the time section.3. Using finite element analysis software ANSYS for nonlinear transient thermalanalysis, by setting the proper initial conditions and boundary conditions respectivelyon three beams subjected to fire, four-pillar and the pillar of fire in different time onthree sides after section temperature field simulation. Then, through the analysis of thedata processing, you can get equivalent fire time, members of the different componentswithin different time-temperature curves of the node data, layer provide a basis for thecalculation of cross section by strength reduction coefficient.4. Analysis of factors affecting reliability of reinforced concrete member after fire.Due to fire of remaining hosted force is to fire of hosted force for Foundation forfolding reduction of, so first to considered fire widget anti-force of effect factors, mainis material strength does not qualitative, and geometry size does not qualitative andcalculation formula does not qualitative, and to out has these random variable ofstatistics parameter; on the considered fire structure widget anti-force of attenuationdegree, this in the is by tiered method calculation fire widget section strength offolding reduction coefficient. On this basis, it is built of reinforced concrete member after fire resistance model and statistical analysis of the statistical parameters ofresistance. Finally, the resistance model and load effect combination of randomness,established a limit State equations.5. Checking point method to the appropriate finish improving. By equivalentnormal non-normal variables, and for several common non-normally distributedstochastic processes, given parameter calculation formula that can be applied directly,greatly simplifying the iterative process, improve the accuracy of calculations,calculation of component reliability after the fire for this article provides theoreticalsupport.6. Considering factors affecting the reliability, combined with engineeringexample, based on the test results, using finite element analysis software ANSYSsimulation equivalent member under fire after time (three-sided fire beams, columnsand four pillars) section temperature field distribution. It is combined with specificmethods in this article, with analysis of its reliability.