A RSM Approximation in Probabilistic Nonlinear Analysis of Fire Resistance of Technology Support Structures

2014 ◽  
Vol 969 ◽  
pp. 1-8 ◽  
Author(s):  
Juraj Králik

This paper presents the methodology of the reliability analysis of the fire resistance of the steel structure of the cable way in NPP. The elastic and plastic solution of the steel structure under fire loads is discussed. The deterministic and probability analysis of the fire resistance of the steel structures are considered. The executed fire resistance analysis of the steel structures is investigated as the influence of temperature, permanent and variable loads. A Response Surface Method (RSM) for the nonlinear analysis of the fire structure reliability was used on program ANSYS. The advantages and disadvantages of the deterministic and probabilistic analysis of the fire safety are discussed.

Author(s):  
Yury Shebeko ◽  
Aleksey Shebeko ◽  
Andrey Zuban

Проанализирована взаимосвязь разброса значений пределов огнестойкости стальных конструкций со вспучивающимися огнезащитными покрытиями и соответствующего этому разбросу интервала толщины огнезащитного покрытия. Предложена методика, на основании которой может быть осуществлен выбор необходимой толщины огнезащитного покрытия в зависимости от заданных значений дисперсии предела огнестойкости и приведенной толщины конструкции при заданной доверительной вероятности.An analysis of a relationship between fire resistance limits scatter for steel structures coated with intumescent fire retardant coating and an appropriate interval of thicknesses of the coating was carried out. A methodology for the determination of this relationship was proposed. This methodology was tested on a practical example. A steel structure with a reduced thickness of 6 mm was considered. A typical dependence of the required thickness of the structure was taken into account. A ratio of a mean square deviation of the fire resistance limit to this limit was accepted to be equal 0.1. Using these values an appropriated interval of the thicknesses of the intumescent fire retardant coating was determined. This interval can be calculated for any given confidence level. Boundaries of this interval can be not symmetric in relation to the value of the normative thickness of the fire retardant coating. The proposed methodology can be used for the determination of the required thicknesses of the intumescent fire retardant coatings on steel structures for the given r value, reduced thickness of the structure and the confidence level.


2010 ◽  
Vol 163-167 ◽  
pp. 790-794
Author(s):  
Feng Bo Yu ◽  
Xin Tang Wang ◽  
Ming Zhou ◽  
Wan Zhen Wang

Pre-stressed steel structures with large space are widely used in stadium, exhibition hall, theater and other buildings today. In order to study the fire-resistance behavior of suspended steel lattice shell of a stadium, the method of performance-based fire resistance design is used. First of all, the stadium physical model is established and the software FDS is used to determine the heating curves of the measuring points of the large space structure for two fire scenes. Compared with international standards heating curve, the heating curves of the large space structure obtained here has characteristic of local high-temperature. The finite element software MSC.MARC is further used to simulate the fire behavior of the pre-stressed steel structure with large space, in which the fire scene with 10MW design power of fire source and 30 minutes duration of fire are considered and two loading ways that overall non-uniform temperature field loading and the local high temperature components loading are accepted. The results show that the pre-stressed steel structure with large space has good fire resistance behavior, and the overall failure will not take place for the fire scene suggested here during 30 minutes duration of fire.


2012 ◽  
Vol 594-597 ◽  
pp. 849-859
Author(s):  
Man Li Ou ◽  
Wei Jun Cao ◽  
Long Min Jiang ◽  
Hui Cao

As the result of great changes occurring to mechanical properties under high temperature (fire) conditions, steel structures will soon lose the strength and stiffness and lead to structural damage. Through analysis of the steel structure fire resistance design methods under the conditions of high temperature (fire), this article explores the most used fire protection methods in steel structures—brushing or painting fire-resistant coatings, studies the fire-resistance theory of steel structure under fire conditions; in addition, the author proposes the reasonable thickness of the steel structure fire retardant coating of fire-resistant design through design examples.


2011 ◽  
Vol 243-249 ◽  
pp. 351-354
Author(s):  
Zhan Sheng Liu ◽  
Rui Long Xu

There have been few researches on the reliability of prestressed steel structure, especially the study on the reliability considering the failure of key components. In order to study the impact of the component failure on the structure reliability, the response surface method based on central composite design is adopted and APDL language is applied to write a corresponding program, thereby carrying out reliability calculation and analysis to the model. The system reliability and parameters sensitivity of the beam string structure under different failure of components are provided. The results indicate that the impact of cable failure on the reliability is large, but it is weak by the failure of brace rod. The results may serve as a reference for the health monitoring and safety assessment of the prestressed steel structure.


2019 ◽  
Vol 968 ◽  
pp. 288-293 ◽  
Author(s):  
Alexey Vasilchenko ◽  
Evgeny Doronin ◽  
Boris Ivanov ◽  
Vladimir Konoval

Calculations on the example of a steel column showed that with the combined effect of an explosion that causes deformation and subsequent fire, even without damaging the fire-retardant coat, there is a significant decrease in the fire resistance of the structure due to a decrease in the critical temperature. It is shown that, on the basis of the methodology proposed in this work, for hazardous operations industrial facilities, it is possible to predict the stability of steel columns in crash explosions followed by fire, as well as to recommend the values ​​of workloads and parameters of fire-retardant coats providing the necessary stability. It is also shown that when calculating the fire resistance limit of a steel structure with intumescent fire-retardant coat, it is necessary to take into account the proper heating time of steel structures until they lose strength.


2018 ◽  
Vol 230 ◽  
pp. 02036 ◽  
Author(s):  
Alexey Vasilchenko ◽  
Yuriy Otrosh ◽  
Nikolay Adamenko ◽  
Evgeny Doronin ◽  
Andrey Kovalov

The problem of estimation of fire resistance of steel frame structures with intumescent coatings is considered. It implies that both physical properties of a covering (its thickness and structure) and mechanical properties of a metal structure change critically at heating. All above changes should be considered to maintain the standard values of fire resistance of a construction at calculation. Usually, known technical characteristics of fire resistance of intumescent coverings are used for estimation of fire resistance of steel structures with intumescent coverings. Importance of taking into account the influence of strength loss time at heating of a steel structure on calculation of fire resistance limit of system “intumescent fireproof coating steel structure” is shown in the article. On an example of calculation of heating time to the critical temperature of steel columns and beams protected by intumescent coating, it is shown that own heating time of steel structures before they lose strength makes 10 to 16 % from a settlement limit of fire resistance. This fact should be considered at the forecast of fire resistance of steel frame structures with intumescent coatings.


2020 ◽  
pp. 116-126
Author(s):  
S.V. Pozdieiev ◽  
◽  
O.M. Nuianzin ◽  
S.O. Sidnei ◽  
A.Y. Novhorodchenko ◽  
...  

In the article, experimental fire tests on establishing maximum fire resistance of the steel columns with fire-retardant mineral wool covering are analyzed. The scientific novelty of this study are the new method developed for manufacturing and shaping samples of the steel columns with fire-retardant mineral wool covering, and the method developed for conducting fire tests on establishing patterns of dependence of the moment when steel columns with the fire-retardant cladding lose their bearing capacity down to the limit. The subject of the study was an influence of design parameters of the fire-retardant cladding on the results of the estimated fire resistance of the steel columns under the influence of the standard fire temperature mode. The main task of the research described in this article was to determine a moment of the peak critical temperature of fire-retardant steel structure depending on the thickness of the mineral wool covering. The test results of samples of steel columns with different thickness of fire-retardant cladding based on mineral wool covering are also described in the article; the tests were carried out in accordance with the developed methodology of experimental studies. The repeatability of the time indicators of the bearing capacity loss by the tested samples of steel columns with fire-retardant cladding depending on the duration of the sample exposure to the action of the fire standard temperature is shown. The obtained research results will allow to create a mathematical model for predicting a dependence of the moment when a steel structure reaches its critical temperature depending on the thickness of the fire-retardant cladding. The constructed mathematical model can be considered as a scientific basis for the creation of new engineering methods of calculation for assessing fire resistance of the steel structures with fire-retardant mineral wool covering. These engineering and calculation methods allow improving the regulatory acts for designing of the fire-resistant steel structures.


2018 ◽  
Vol 763 ◽  
pp. 270-278
Author(s):  
Ji Hye Seo ◽  
Deok Hee Won ◽  
Woo Sun Park ◽  
Seung Jun Kim

Recently, several lives were lost because of the collapse of structures under fire. Steel members are mainly used in the columns and beams of buildings for improving construction efficiency. The fire resistance of steel structure is very important because when it don’t have fire resistive covering, it rapidly changes with high temperature. In fire resistance design of steel, steel structure must have fire resistive covering. But many facilities as temporary facilities, parking lot don’t have it. The buckling behavior of steel structures under fire is also significant because it can cause local buckling failure through the reduction in structural material properties by temperature. In this study, the elastic buckling behavior of a circular steel tube under fire was investigated using finite element analysis. The parameters for this analysis used were, diameter–thickness ratio, fire exposure area, and fire scenarios. The elastic buckling strength of circular steel tube rapidly decreased when subjected to the fire curve. Local buckling occurred and this can lead to global failure. When fire resistance design of circular steel tube was performed, buckling behavior must be considered.


2011 ◽  
Vol 255-260 ◽  
pp. 2341-2344
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Ali Jahanshahi

This paper presents the performance of base-isolated steel structures under the seismic load. The main goals of this study are to evaluate the effectiveness of base isolation systems for steel structures against earthquake loads; to verify the modal analysis of steel frame compared with the hand calculation results; and development of a simulating method for base-isolated structure’s responses. Two models were considered in this study, one a steel structure with base-isolated and the other without base-isolated system. The nonlinear time-history analysis of both structures under El Centro 1940 seismic ground motion was used based on finite element method through SAP2000. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as time-acceleration graphs for each story, period and frequency of both structures for the first three modes.


Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.


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