scholarly journals DEVELOPMENT OF FIRE-PROTECTIVE PLASTER SURFACES COMPOSITES AND DESIGN METHOD FOR DETERMINING THE FIRE RESISTANCE OF TWO-LAYER ARMOCEMENT ELEMENTS

2019 ◽  
Author(s):  
Т.А. Хежев
Keyword(s):  
Fire Resistance ◽  
Design Method ◽  
Experimental Studies ◽  
Engineering Calculation ◽  
Building Structures ◽  
Resource Base ◽  
Heat Engineering ◽  
Flame Retardant Properties ◽  
Increased Strength ◽  
Acceptable Agreement

Приведены результаты исследований составов гипсоизвестковоцементовермикулитотуфобетонных композитов. Расширение сырьевой базы, повышение прочности и огнезащитных свойств, а также снижение стоимости композита решается за счет использования в сырьевой смеси отходов пиления вулканического туфа. Приведены результаты экспериментальных исследований огнестойкости двухслойных армоцементных элементов. Разработан алгоритм теплотехнического расчета предела огнестойкости многослойных строительных конструкций, обеспечивающий приемлемое совпадение расчетных значений с экспериментальными данными. Разработано программное обеспечение теплотехнического расчета предела огнестойкости армоцементных конструкций с огнезащитным слоем из гипсовермикулитобетона, получены выражения для коэффициентов теплопроводности и теплоемкости разработанных композитов. The results of studies of gypsumlimestone cementvermiculite and concrete composites are given. Expanded resource base, increased strength and flame retardant properties, as well as reduced cost of the composite. using volcanic tuff in the raw mix. The results of experimental studies of the fire resistance of twolayer cementcontaining elements are given. An algorithm for heat engineering calculation of the fire resistance limit of multilayer building structures has been developed, which ensures acceptable agreement between the calculated values and experimental data. The software for the heat engineering calculation of the fire resistance limit of cementcement constructions with a fireproof layer made of gypsum vermiculite concrete has been developed, expressions for the thermal conductivity and heat capacity of the developed composites have been obtained.

scholarly journals A Review on Progressive Collapse of Building Structures

2014 ◽  
Vol 8 (1) ◽  
pp. 183-192 ◽  
Author(s):  
Hao Wang ◽  
Anqi Zhang ◽  
Yi Li ◽  
Weiming Yan
Keyword(s):  
Design Method ◽  
Progressive Collapse ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Collapse Mechanism ◽  
Building Structures ◽  
Wide Range ◽  
Collapse Behavior ◽  
Element Method

Progressive collapse of building structures is generally triggered by a local failure due to accidental actions, followed by subsequent chain effect of the structures which may result in wide range failure or even collapse of the entire buildings. Since the “911” event, progressive collapse of building structures has been widely concerned by engineers and researchers. This paper assesses the current researches on this issue from experimental study, numerical simulation and theoretical analysis. Given the limitation of costs and difficulties of experimental tests, the experimental studies investigate the collapse mechanism, such as development of stress/strain and damage/failure of materials, mainly via the scaled down specimens of structural components and substructures. On the other hand, the collapse behavior of entire building structures is analyzed via the numerical methods, such as the finite element method and the discrete element method. Further, the collapse resistance demand and the robustness assessment for building structures are theoretically studied in depth in which the simplified theoretical models of the collapse-resisting demand and the collapse risk assessment are proposed respectively. At last, the design method to prevent progressive collapse for building structures is also discussed.

scholarly journals Fire Resistance of Steel Composite Beams without Fire Protection

2020 ◽  
Vol 20 (5) ◽  
pp. 83-89
Author(s):  
Jaekwon Ahn ◽  
Inhwan Yeo ◽  
Gyuhwan Cho ◽  
Kyujae Hwang
Keyword(s):  
Fire Resistance ◽  
Design Method ◽  
Load Ratio ◽  
Composite Beams ◽  
Building Structures ◽  
Fire Exposure ◽  
Standard Fire ◽  
Steel Composite ◽  
Fire Design ◽  
Exposure Conditions

In this study, the fire resistance of steel composite beams typically used in building structures was investigated through standard fire and loading tests. For the tests, fire-exposure conditions depending on the steel section shape and load ratio applied to the beams were considered as the test parameters. Based on the test results, the applicability of fire design methods for composite beams recommended in current domestic and overseas fire design codes was analyzed. The results indicate that the current temperature-based design method and reduced flexural capacity method specified by the American Institute of Steel Construction may lead to the conservative fire design of steel composite beams owing to the underestimation of the effects of the fire-exposure conditions and load ratios.

scholarly journals Screen Wall Fire Resistance Investigation

2021 ◽  
Vol 6 ◽  
Author(s):  
Tatiana Eremina ◽  
Dmitry Korolchenko ◽  
V. E. Fadeev
Keyword(s):  
Fire Resistance ◽  
Functional Dependence ◽  
Heat Exposure ◽  
Experimental Studies ◽  
Engineering Problem ◽  
Thermal Engineering ◽  
Wall Structure ◽  
Building Structures ◽  
Critical Temperatures ◽  
Fire Conditions

The assessment of fire resistance for building constructions has been carried out by the solution of the heat engineering problem for heating up building structures under the conditions of non-stationary heat exposure with standard fire conditions. The finite element method is used as the solution method. Numerical simulation of heating of considered building structures under fire conditions was carried out using the Ansys Mechanical computer complex, which allows for a thermal engineering design to be calculated on the basis of its software model. The resulting functional dependence allows for determining the actual fire resistance of Pf depending on the thickness of sheets δ of the outer skin made of the basalt fire-proof material, as well as the geometric parameters of the protective screen (δ) depending on the required fire resistance from the condition of compliance with the requirements of constructive fire safety (Pf > Preq). Experimental studies to determine the fire resistance for membrane wall structures showed that an increase in temperature on its unheated surface vs. structure temperature prior to testing more than 180° С (195°С) occurs not earlier than 31 min. Upon reaching the critical temperatures on the unheated surface of the membrane wall structure independing on its thickness, the fire resistance limits REI 30-REI 120 are reached.

scholarly journals VERIFICATION RESULTS OF THE PRESENTATION OF THE PROTECTION OF THE UNSTEADING TEMPERATURE FIELD AT THE CONCRETE CONSTRUCTION FOR THE MIND OF THESTANDARD TEMPERATURE REFRIGERATION FIRE

2018 ◽  
pp. 96-101 ◽  
Author(s):  
O. Pazen
Keyword(s):  
Temperature Field ◽  
Experimental Research ◽  
Fire Resistance ◽  
Concrete Structure ◽  
Experimental Studies ◽  
Alternative Methods ◽  
Building Structures ◽  
Fire Tests ◽  
Stationary Temperature Field ◽  
The Phoenix

The main classification indicator, in terms of fire safety, is the degree of fire resistance of the house. Depending on this indicator normalize its surface, the area of development and distance to other buildings and structures. The degree of fire resistance of the house is determined by the limit of fire resistance of its building structures and the limit of the fire spread by these structures. Therefore, the value of the fire resistance limit of building constructions, which consists of a house, significantly affect its architectural solution and the parameters of construction in general. On this basis, taking into account the approaches to ensuring normalized fire resistance limits of the design and the features of their behavior under high-temperature (fire) influence is very relevant. Most research on building constructions is based on two methods of determining the limit of fire resistance - experimental and analytical. The first one is to determine the limit of fire resistance on the basis of experimental research, and the second one is based on methods of analytical or computational and experimental research. In most countries, the experimental determination of fire resistance of building structures is carried out by means of fire tests. However, experimental studies require significant financial costs and high accuracy of fire tests. The alternative methods for assessing the fire resistance of building elements on the basis of field fire tests are the design methods used for the design of fire-resistant building constructions. In the article, the verification of the results of analytical studies on the propagation of the non-stationary temperature field in the concrete structure under the conditions of the influence of the standard temperature regime of the fire in comparison with the results of field fire tests has been carried out. The analysis of the obtained results shows that the results of the calculation of the distribution of the non-stationary temperature field in the thickness of the concrete structure without coating and with the applied flame retardant coating of the Phoenix STV, manufactured by the company "A + B Ukraine" on the front of the Phoenix Contact, obtained using mathematical models, are qualitatively and quantitatively convergent with results obtained experimentally. The difference between the theoretical and experimental data for a concrete structure without coating is 4%, and with the applied fire-retardant coating does not exceed 10%.

Calculation And Experimental Substantiation Of Optimal Design Of The Welded Joint Of Plates On Соver Plates

2020 ◽  
pp. 17-24
Keyword(s):  
Welded Joint ◽  
Experimental Studies ◽  
Engineering Calculation ◽  
Tensile Tests ◽  
Physical Nonlinearity ◽  
Steel Plates ◽  
Optimal Parameters ◽  
Actual Problem ◽  
Numerical Research ◽  
Cover Plates

The article is devoted to the actual problem of assigning optimal parameters for connecting steel plates on cover plates with angular welds that are widely used in construction practice. The article presents the results of a comprehensive study of operation of a welded assembly of the plates connection on cover plates. An algorithm is proposed for determining the optimal parameters of a welded joint with fillet welds on the cover plates, which makes it possible to obtain a strength balanced connection. The results of full-scale tensile tests of models were presented. These results confirmed the correctness of the assumed design assumptions, and made it possible to obtain a form of destruction, not characteristic and not described in the normative literature, expressed by cutting the main elements along the length of the overlap in the joint. The possibility of such a form of destruction was confirmed by the results of numerical research in a nonlinear formulation. The optimal parameters of the nodal welded joint determined by engineering calculation are confirmed by experimental studies, as well as by the results of numerical experiments on models of calculation schemes, taking into account the physical nonlinearity of the material operation. The obtained dependence for determining the bearing capacity of the joint by the cut-off mechanism and the expression for limiting the overlap length of the cover plates will make it possible to predict the nature of the fracture and design equally strong joints.

Assessment of the volume activity of α-radioactive wastes on surface and specific contamination by portable γ-spectrometry method

2020 ◽  
pp. 468-473
Author(s):  
I. P. Korenkov ◽  
A. I. Ermakov ◽  
A. B. Mayzik ◽  
T. N. Laschenova ◽  
V. N. Klochkov ◽  
...  
Keyword(s):  
Specific Activity ◽  
Experimental Studies ◽  
Germanium Detector ◽  
Low Energy ◽  
Gamma Ray Spectrometry ◽  
Building Structures ◽  
Germanium Detectors ◽  
Volume Activity ◽  
Β Decay ◽  
Γ Spectrometry

The aim of the study is to evaluate the volume activity of radioactive waste (RW) by surface and specific alpha contamination using portable gamma-spectrometry.Materials and methods. Methods of rapid assessment of the content of α-emitting radionuclides in solid waste of various morphologies using gamma-spectrometers based on germanium detectors are considered. Computational methods for determining the effectiveness of radionuclide registration are presented.Results. The possibility of using portable gamma-ray spectrometry to assess the surface and specific activity of various materials contaminated with α-emitters (232Th, 235U, 238U, 237Np, 239Pu, 240Pu and 241Am) is shown. The calculated values of the registration efficiency of low-energy gamma-emitters obtained by modeling the spatial-energy parameters of the detector are given.To simplify the solution of this problem, the calculation program used 20 standard templates of various geometries (rectangular, cylindrical, conical, spherical, etc.). The main sources of error in the survey of contaminated surfaces, largesized equipment and building structures were investigated.Conclusions. The possibilities of portable γ-spectrometry for estimating the volume of RW based on the surface density of contamination of materials with radionuclides of uranium and transuranic elements are investigated. When using γ-spectrometer with a high-purity germanium detector with a range of γ-quanta extended in the low-energy region, radionuclides such as 232Th, 235U,238U, 237Np, 241Am were determined by their own radiation or by the radiation of their daughter products.The “problem” element is plutonium, for rapid evaluation of which it is proposed, in accordance with the radionuclide vector methodology, to use 241Am, which accumulates during the β-decay of 241Pu.According to calculations, the most likely value of the activity ratio 239Pu/241Am for the object where the work was performed (scaling factor) varies in the range from 5.0 to 9.0.Based on the results of calculations and experimental studies, the parameters of the efficiency of registration of various α-emitting radionuclides by portable γ-spectrometers. It has been found that for germanium detectors with an absolute efficiency of registering a point source of 7÷15%, it is n×10–5÷n×10–4%.

Development of an Evaporating Type Air Cooler for Ventilation Systems

2021 ◽  
pp. 37-44
Author(s):  
А. В. Бараков ◽  
В. Ю. Дубанин ◽  
Д. А. Прутских ◽  
А. А. Надеев
Keyword(s):  
Experimental Studies ◽  
Engineering Calculation ◽  
Design Calculation ◽  
Efficiency Coefficient ◽  
Empirical Relationships ◽  
Additional Energy ◽  
Air Cooler ◽  
Hot Season ◽  
Experimental And Theoretical Studies ◽  
Ventilation Systems

Постановка задачи. Подаваемый в помещения воздух в жаркое время года должен быть охлажден до комфортных температур. В связи с тем, что дополнительного расхода энергии на это охлаждение не предусмотрено, возможно применить воздухоохладитель испарительного типа. Однако известные в настоящее время результаты экспериментальных и теоретических исследований таких аппаратов не позволяют их проектировать, что препятствует их распространению. Рассмотрено строение такого аппарата и выполнены его теоретические и экспериментальные исследования, результаты которых могут быть использованы для инженерного расчета и конструирования подобных аппаратов. Результаты. Описан сконструированный авторами воздухоохладитель испарительного типа для систем вентиляции. Проведено теоретическое и экспериментальное исследование воздухоохладителя. Получены аналитические соотношения для определения времени движения насадки в «мокрой» камере аппарата, температуры охлажденного воздуха и температуры насадки в любом сечении контура циркуляции. Получены эмпирические соотношения для коэффициента эффективности охладителя и его гидравлического сопротивления. Выводы. Полученные зависимости послужат основой для разработки методики проектного расчета воздухоохладителей косвенно-испарительного типа с перемещающимся псевдоожиженным слоем в поле центробежных сил. Statement of the problem. The air supplied to the premises during the hot season must be cooled to comfortable temperatures. Due to the fact that additional energy consumption for this cooling is not provided, it is possible to use an evaporative-type air cooler. However, the currently known results of experimental and theoretical studies of such devices do not allow for their design, which prevents their spread. The structure of such an apparatus is considered and its theoretical and experimental studies are carried out, the results of which can be used for engineering calculation and design of such apparatus. Results. An evaporative-type air cooler designed by the authors for ventilation systems is described. A theoretical and experimental study of the air cooler has been carried out. Analytical relationships were obtained for determining the time of movement of the material checker in the «wet» chamber of the apparatus, the temperature of the cooled air and the temperature of the checker in any section of the circulation loop. Empirical relationships have been obtained for the efficiency coefficient of the cooler and its hydraulic resistance. Сonclusions. The obtained dependencies will serve as the basis for the development of a methodology for the design calculation of indirect-evaporative air coolers with a moving fluidized bed in the field of centrifugal forces.

The concept of calculating the actual limit of fire resistance of building structures

2021 ◽  
pp. 12-17
Author(s):  
Юрий Николаевич Шебеко ◽  
Алексей Юрьевич Шебеко
Keyword(s):  
Fire Resistance ◽  
Fire Safety ◽  
Building Structures ◽  
Safety Level ◽  
Fire Temperature ◽  
Normative Documents ◽  
Software Complex ◽  
Temperature Regimes ◽  
Actual Fire

Проведен краткий анализ понятий, связанных с расчетом пределов огнестойкости строительных конструкций. Дано определение термина «фактический предел огнестойкости», которое отсутствует в нормативных документах по пожарной безопасности. Отмечено, что это связано с использованием на практике значений пределов огнестойкости, определенных для стандартных температурных режимов пожара, в то время как на практике указанные температурные режимы, как правило, отличаются от стандартных. Предложена концепция определения фактического предела огнестойкости, основанная на моделировании воздействия на строительную конструкцию температурного режима реального пожара (например, с помощью программного комплекса FDS 6). The brief analysis of definitions connected with estimation of fire resistance limits of building structures is conducted. There is given the determination of term “actual fire resistance limit” that is absent in fire safety normative documents. It is caused by practical application of the fire resistance limits determined for standard temperature regimes of fires only, but at the same time the temperature regimes of real fires as a rule differ from the standard regimes. There is proposed the method for determination of the actual fire resistance limit based on the modeling of influence of the real fire temperature regime on buildings structures. This modeling can be made by an application of CFD methods (for example, with the help of FDS 6 software complex). The required reliability of the building structure is considered. The proposed method can solve the problem of practical applicability of certain structural unit during designing buildings and structures, for which the use of the resistance limits obtained for the standard fire temperature regimes can lead to unjustified economic expenditures without an appropriate elevation of fire safety level of the object.

Fire-Resistance Design Method for Stainless Steel Tubular X-Joints

2022 ◽  
Vol 148 (1) ◽  
Author(s):  
Runmin Ding ◽  
Shenggang Fan ◽  
Lianlian Jia ◽  
Hang Zhou
Keyword(s):  
Stainless Steel ◽  
Fire Resistance ◽  
Design Method

scholarly journals Possibilities of modern software complexes in simulation fire protection of constructions structures with Sofistik

2018 ◽  
Vol 193 ◽  
pp. 03026 ◽  
Author(s):  
Marina Gravit ◽  
Vladimir Lyulikov ◽  
Alina Fatkullina
Keyword(s):  
Fire Resistance ◽  
Fire Protection ◽  
Software Systems ◽  
Building Structures ◽  
Temperature Regimes

The review of modern software systems that allow producing modeling and calculation of fire resistance of building structures, as well as simulating fire protection, is given. Particular attention is paid to the software Sofistik, which allows you to synchronize with Autodesk Revit and calculate the fire protection of building structures for various temperature regimes.

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