Investigation of the Limit of Fire Resistance of a Steel Beam at Loss of Integrity of a Fire-Resistant Lining

2021 ◽  
Vol 1038 ◽  
pp. 345-351
Author(s):  
Oleksandr Nuianzin ◽  
Serhii Pozdieiev ◽  
Olena Borsuk ◽  
Olha Nekora
Keyword(s):  
Fire Resistance ◽  
Heating Temperature ◽  
Limit State ◽  
Fire Retardant ◽  
Mineral Wool ◽  
Steel Beam ◽  
Geometrical Parameters ◽  
Maximum Deflection ◽  
Standard Temperature ◽  
Rate Of Increase

In this article, to solve the main problems, we determined the temperature regime of heating the steel beam, which took into account the fact of loss of integrity of the fire-retardant lining due to the thermal effects of fire. When calculating the temperature, the time of exposure to the standard temperature of the fire and the value of the heating temperature of the steel beam with mineral wool lining at which the latter loses its integrity was determined. Taking into account the geometrical parameters of the cross section of the studied I-beam, according to the finite-element scheme, the steel beam was divided into four elements of SHELL type with five points of integration in thickness in the Belichko-Tsai formulation. After the calculation, the corresponding results were obtained in the form of graphs of changes in the maximum deflection of the beam and the rate of increase of the maximum deflection depending on the time of exposure to the standard temperature of the fire. The critical values of the occurrence of the limit of fire resistance according to the graph of maximum deflection and the graph of the rate of increase of deflection were determined. The difference between the indicators shows that the time of the limit state of loss of bearing capacity is 70 min less, if not taking into account the loss of fire-retardant capacity of mineral wool fire-protection due to loss of integrity.

Research heating of the steel i-beam rods with mineral wool coating under the conditions of standard temperature fire regime

2020 ◽  
pp. 116-126
Author(s):  
S.V. Pozdieiev ◽  
◽  
O.M. Nuianzin ◽  
S.O. Sidnei ◽  
A.Y. Novhorodchenko ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Fire Resistance ◽  
Fire Retardant ◽  
Steel Structure ◽  
Steel Structures ◽  
Mineral Wool ◽  
Fire Tests ◽  
Standard Temperature ◽  
Steel Columns ◽  
The Moment

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.

Application of Fuzzy Set Theory to the Serviceability Limit State of a Steel Beam under Bending

2015 ◽  
Vol 769 ◽  
pp. 91-96
Author(s):  
Jan Vales ◽  
Zdenek Kala ◽  
Jindrich Melcher
Keyword(s):  
Limit State ◽  
Major Axis ◽  
Steel Beam ◽  
Maximum Deflection ◽  
Geometric Imperfection ◽  
Serviceability Limit State ◽  
Limit Value ◽  
Initial Geometric Imperfection ◽  
Slender Beams ◽  
Limiting Condition

Deformations of an I-section steel beam under equal end moments are studied in this article. Initial geometric imperfection of the beam axis was introduced according to the Eurocode standard. Numerical studies have shown that the lateral deflection of slender beams under major axis bending can be relatively high. The acceptability of high values of lateral deflections within the framework of the serviceability limit state is discussed. In the next part of the paper, the limit value of maximum deflection was introduced as a fuzzy number. Fuzzy analysis of the maximum moment, which causes maximum deflection, was performed. The slenderness values of beams for which the serviceability limit state is the limiting condition for design were identified.

Influence of the Fire Temperature Regime on the Fire-Retardant Ability of Reinforced-Concrete Floors Coating

2020 ◽  
Vol 1006 ◽  
pp. 87-92
Author(s):  
Andrii Kovalov ◽  
Yurii Otrosh ◽  
Oleg Semkiv ◽  
Volodymyr Konoval ◽  
Oleksandr Chernenko
Keyword(s):  
Reinforced Concrete ◽  
Fire Resistance ◽  
Temperature Regime ◽  
Fire Retardant ◽  
Protective Layer ◽  
Fire Regimes ◽  
Hollow Core ◽  
Standard Temperature ◽  
Concrete Floor

In the paper, the tests have been analysed for fire-resistant quality of the hollow-core reinforced-concrete floors with fire-retardant plaster covering under standard temperature regime of the fire. Using the methodology for determining the characteristics of fire-retardant coatings ability for reinforced-concrete floors, the dependences have been obtained of the fire-retardant coating thickness from the concrete protective layer of a hollow-core reinforced-concrete floor for a fire resistance limit of 180 minutes with a temperature regime of hydrocarbon fire and a tunnel curve according to the Netherlands standards (RWS). It has been concluded about the minimum required thickness of the studied fire-retardant coating to provide the required fire resistance limit of a hollow-core reinforced-concrete floor under the indicated fire regimes.

EVALUATION OF FIRE RESISTANCE OF FIRE PROTECTED STEEL STRUCTURES

2021 ◽  
pp. 149-158
Author(s):  
Andrii Kovalov ◽  
◽  
Yurii Otrosh ◽  
Vitalii Tomenko ◽  
Andrii Kondratiev ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Experimental Method ◽  
Fire Resistance ◽  
Fire Retardant ◽  
Steel Structures ◽  
Resistant Steel ◽  
Standard Temperature ◽  
Steel Columns ◽  
Steel Column ◽  
Fire Resistant Steel

Purpose. Evaluation of fire resistance of fire-resistant steel structures using the developed calculation and experimental method. Methods. Finite difference method, landfill fire test method, mathematical and computer modeling of non-stationary heat exchange processes, determination of thermophysical characteristics of fire-retardant coatings based on solving direct and inverse thermal conductivity problems. Results. Geometric, physical, computer models have been developed, with the help of which the fire resistance of fire-resistant steel structures has been evaluated by the calculation-experimental method. The adequacy of the developed method for assessing the fire resistance of fire-resistant steel structures in assessing the fire resistance of fire-resistant I-beam steel column has been checked. The analysis of tests on fire resistance of fire-resistant steel columns exposed to fire at the standard temperature of the fire without the load applied to them has been carried out. A computer model of the “steel column – reactive flame retardant coating” system has been built for numerical simulation of non-stationary heating of such a system. The fire resistance of fire-resistant steel columns of I-beam section without load applied to them has been evaluated using the calculation-experimental method. Verification of results of experimental research with results of numerical modeling has been carried out. Scientific novelty. The convergence of the results of experimental data on the duration of fire exposure at the standard temperature of the fire to reach the critical temperature of steel with the results of numerical simulations has been determined. Based on the comparison of the experimental results and numerical modeling, the adequacy of the developed model to the real processes that occur when heating fire-retardant steel columns without applying a load under fire conditions at a standard fire temperature has been confirmed. The efficiency of the proposed calculation and experimental method for assessing the fire resistance of fire-resistant steel structures has been confirmed. Practical significance. It consists in the implementation of the results on objects of different purposes in assessing the fire resistance of fire-resistant steel structures by evaluating the effectiveness of fire-retardant coatings of steel building structures.

INVESTIGATION OF THE EFFICIENCY OF THE STEEL TUBE CONFINEMENT CONCRETE PILLARS PROTECTION BY FIRE-RETARDANT MATERIALS

Fire Safety ◽  
2018 ◽  
pp. 95-100
Author(s):  
M. Semerak ◽  
D. Kharyshyn ◽  
N. Ferents ◽  
T. Berezhanskyi
Keyword(s):  
Flame Retardant ◽  
Fire Resistance ◽  
Fire Protection ◽  
Flame Retardants ◽  
Rapid Heating ◽  
Fire Retardant ◽  
Concrete Columns ◽  
Steel Tube ◽  
Mineral Wool ◽  
Concrete Core

Currently, in Ukraine and abroad for the construction of high-rise buildings and structures using pipe-like structures. Wide application of pipe concrete columns is due to their high carrying capacity at relatively smaller overall dimensions due to the blocking of cracking in concrete by a steel clasp. The advantages of concrete columns should include more simplified conditions of technology of manufacturing and installation on their basis of bearing structures of floor covering. Piping constructions consist of steel shells and concrete core. Since the steel pipe mainly provides the bearing capacity of the concrete column, its failure or reduction of stiffness, which is characteristic of the fire under the influence of its thermal factors, leads to destruction. Investigation of fire resistance of concrete structures, which are not protected by flame retardant coatings, showed that a steel clasp during a fire after 15 minutes is heated to a critical temperature of 500 ° C.The use of flame retardant coatings is an effective method of fire protection of concrete constructions, which prevents the rapid heating of steel welds and provides a normalized fire resistance limit for such structures. In this work, studies were carried out on the effectiveness of fire protection of concrete columns with different types of fire-retardant materials - mineral wool slabs, special flame retardants and flame-retardant coatings. For fire protection mineral wool materials were used ROCKWOOL plates of the series "Conlit SL150". Mineral wool plates "Conlit SL 150" consist of fibers of rocks of a basalt group, they can withstand, without melting, temperature more than 1000 ° С. The silica-based adhesive "Conlit Glue" can withstand temperatures above 900 ° C, has good adhesion when bonding Conlit SL 150 mineral wool slabs with protective structures. From the second type of fire-retardant materials, the fire-proof composition "Naktresk" was chosen on the basis of gypsum. The coating is formed in the process due to hardening of the mixture on protected surfaces. The third type of flame retardant materials is the flame-retardant intumessent coating "Pyro-Safe Flammoplast SP-A2".It has been established that with the use of fire protection systems on the basis of mineral wool plates "Conlit SL150" and fire retardant "Nutresc", the fire resistance class of reinforced concrete columns increases from R 15 to R 180. The fire protection system on the basis of the painted paint "Pyro-Safe Flammoplast SP-A2" »Increases fire resistance from R 15 to R 75

scholarly journals Thermal effect of a fire on a steel beam with corrugated wall with fireproof mineral-wool cladding

2021 ◽  
Vol 5 (1(113)) ◽  
pp. 24-32
Author(s):  
Valeriia Nekora ◽  
Stanislav Sidnei ◽  
Taras Shnal ◽  
Olga Nekora ◽  
Ludmila Lavrinenko ◽  
...  
Keyword(s):  
Cross Sections ◽  
Fire Resistance ◽  
Heating Temperature ◽  
Mineral Wool ◽  
Steel Beams ◽  
Radiant Heat Transfer ◽  
The European Union ◽  
Simplified Method ◽  
The Cross ◽  
Corrugated Wall

This paper reports a study into the possibility of applying a simplified approach, recommended by standards for conventional steel beams, to determine the heating temperature under the conditions of a fire in relation to steel I-beams with a corrugated wall. The research is predetermined by the limitation of methods that make it possible to determine the heating temperature of this type of beam in a fire using engineering methods with a small amount of calculations. Technical data on steel beams with cladding have been considered for calculation, the features of heat impact of fire on them have been analyzed, a calculation procedure has been devised, the estimation schemes have been built, and the calculations have been performed. Data on the temperature distribution in the cross-sections of beams with and without cladding were obtained by using a simplified method recommended by standards and the refined method based on a finite-element method. Mathematical models have been constructed for calculations that describe the effect of a standard temperature regime of fire on the distribution of temperature in each minute in the cross-sections of steel beams with and without cladding. The models have been described on the basis of the differential equation of thermal conductivity, boundary conditions of the third kind, which take into consideration convective and radiant heat transfer. It was established that the mineral wool cladding of the beam with a corrugated wall is a reliable fire protection agent. The heating temperature of the beam does not reach a critical value of 500 °C in 60 minutes, which provides the class of this beam with the most stringent requirements for its fire resistance in accordance with the classification in line with the acting norms in Ukraine. The simplified method, recommended by the current standards of the European Union and Ukraine, could be effectively used to analyze the fire resistance of these beams and is the basis of the procedure for the estimated assessment of the fire resistance of these structures

scholarly journals EVALUATION OF FIRE-PROTECTIVE ABILITY OF NEWLY CREATED FIRE-PROTECTIVE COATINGS OF STEEL STRUCTURES

2021 ◽  
pp. 79-88
Author(s):  
A. Kovalov ◽  
◽  
Y. Otrosh ◽  
V. Tomenko ◽  
O. Vasylyev ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Fire Resistance ◽  
Fire Protection ◽  
Experimental Studies ◽  
Fire Retardant ◽  
Steel Structures ◽  
Steel Plates ◽  
Thermal Calculation ◽  
Thermophysical Characteristics ◽  
Standard Temperature

Abstract. The results of the development of fire-retardant substances based on domestic materials to increase the fire resistance of fire-retardant steel structures are presented. New compositions of fire-retardant substances on the basis of domestic materials capable of swelling are developed. A series of experimental studies to determine the heating temperature of fire-resistant steel structures. For this purpose, samples of reduced size in the form of a steel plate with a flame retardant applied to the heating surface were used. Fire tests of fire-retardant steel plates coated with the developed fire-retardant substance forming a coating on the protected surface, in the conditions of their tests on the standard temperature of the fire using the installation to determine the fire-retardant ability of fire-retardant coatings. The results of experimental determination of temperature from an unheated surface of steel plates with a fire-retardant covering in the conditions of fire influence at a standard temperature mode of a fire are analyzed. Based on the obtained data (temperature in the furnace and from the unheated surface of steel plates with fire protection system) the solution of the inverse problems of thermal conductivity found thermophysical characteristics of fire protection coating (thermal conductivity and specific volume), which can be used for thermal calculation heating of fire-retardant steel structures at arbitrary fire temperatures. The thermophysical characteristics of the formed fire-retardant coating are substantiated to find the characteristics of the fire-retardant ability of the newly created fire-retardant coating and to ensure the fire resistance of fire-retardant steel structures. The efficiency of the developed fire-retardant coating for protection of steel structures is proved.

scholarly journals EVALUATION OF FIRE RESISTANCE OF FIRE PROTECTED STEEL STRUCTURES BY CALCULATION AND EXPERIMENTAL METHOD

2021 ◽  
Vol 3 (2) ◽  
pp. 29-39
Author(s):  
A. Kovalov ◽  
◽  
Y. Otrosh ◽  
V. Tomenko ◽  
V. Slovinskyi ◽  
...  
Keyword(s):  
Experimental Method ◽  
Fire Resistance ◽  
Fire Retardant ◽  
Steel Structures ◽  
Resistant Steel ◽  
Standard Temperature ◽  
Steel Columns ◽  
Steel Column ◽  
Stationary Heating ◽  
Fire Resistant Steel

Based on the developed geometric, physical, computer and finite element model, the fire resistance of fire-resistant steel structures was evaluated by calculation and experimental method. The adequacy of the developed computational-experimental method for assessing the fire resistance of fire-resistant steel structures in assessing the fire resistance of a fire-resistant I-beam steel column was verified. The results of tests for fire resistance of steel columns with fire-retardant coating at standard temperature of the fire without the load applied to them (temperature in the furnace, temperature in certain places on the surface of fire-retardant steel columns, the behavior of the investigated fire-retardant coating). The analysis of tests on fire resistance of fire-resistant steel columns exposed to fire at standard temperature (temperature in the furnace, temperature in places of measurement of temperature on a surface of columns, behavior of a fire-retardant covering) is carried out. A computer model of the «steel column – reactive flame retardant coating» system has been built for numerical simulation of non-stationary heating of such a system. Simulation of non-stationary heating of the system «steel column – fire-retardant coating» in the software package FRIEND with the specified parameters (geometric model, thermal effects, initial and boundary conditions, properties of system materials). The reliability of the results of numerical modeling with real experimental data on the duration of fire exposure at the standard temperature of the fire to reach the critical temperature of steel. Based on the comparison of experimental results and numerical simulations, a conclusion is made about the adequacy of the developed model to the real processes that occur when heating fire-retardant steel columns without applying a load under fire conditions at standard fire temperature. The efficiency of the proposed calculation and experimental method for assessing the fire resistance of fire-resistant steel structures has been confirmed.

scholarly journals Investigation of the influence of the configuration of the fire furnace chamber on the temperature regime during the implementation of tests for fire resistance

2021 ◽  
Vol 4 (1(112)) ◽  
pp. 34-40
Author(s):  
Serhii Pozdieiev ◽  
Vadym Nizhnyk ◽  
Yurii Feshchuk ◽  
Valeriia Nekora ◽  
Oleksandr Nuianzin ◽  
...  
Keyword(s):  
Computer Model ◽  
Fire Resistance ◽  
Temperature Regime ◽  
Ventilation System ◽  
Furnace Chamber ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Building Structures ◽  
Standard Temperature ◽  
Fire Temperature

The issue related to the conditions for creating the required temperature regime of fire when testing structures for fire resistance has not been studied in detail up to now. That necessitated determining the technical conditions under which it is possible to comply with the standard temperature regime of fire in the fire chamber of the furnace. The influence of the design parameters of the fire furnace chamber on the condition of compliance with the standard fire temperature regime when tested for fire resistance has been established. One of the most effective methods for examining such an impact is computer simulation. A computer model of the fire furnace was built on the basis of a comprehensive analysis and earlier work on the study of such furnaces, taking into consideration technical characteristics, in particular, geometrical parameters, fuel and air supply systems. The obtained research results are a prerequisite for scientific substantiation of the design parameters of fire furnaces and their engineering systems, which is necessary to comply with the standard temperature regime of fire in the furnace fire chamber. This makes it possible to provide the necessary conditions for testing building structures for fire resistance in compliance with the requirements of the relevant standards. The computer model constructed makes it possible to create the necessary temperature regime in the fire chamber of the furnace (in this study, the standard temperature of fire). As a result of the study, the technical parameters of the fuel supply and ventilation system were determined, which ensure compliance with the standard temperature regime in the fire chamber of the furnace. That makes it possible to build an automated complex of the testing process for fire resistance of building structures. In addition, the data obtained can be the basis for the design of such fire furnaces with the ability to comply with different fire temperature regimes without the intervention of the operator.

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