scholarly journals Contribution to the design of bolted angle connection in the steel structures

Author(s):  
Dragan Velickovic

The paper presents the equations for the determination of the neutral axis position, when it is on the face, that is, on the bearing plate, and for the highest normal tensile stress in the fastener, as well as for the determination of highest and lowest normal compressive stress occurring on the face, that is bearing plate when the neutral axis is outside the face that is, the bearing plate. Which of these three possible cases will occur depends solely on the force field occurring in the given cross-section for the dimensioning of the joint. The connection is effected by the face or bearing plate, depending on the task being solved and the bolt fasteners. The expressions for the calculation of the said connections are derived for the general case when all three forces intersecting, M, T and N, in the cross section given for their dimensioning, are other than zero or any one of them is other than zero. The paper also presents a tabular presentation of the results for all of the three possible cases of the force fields, that is, the stress fields most frequently occurring in the civil engineering building practice at these joints.

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.


2019 ◽  
Vol 290 ◽  
pp. 03008
Author(s):  
Marek Kowalik ◽  
Tomasz Trzepiecinski

This paper presents the methods of experimental determining the depth of the plastically deformed top layer in the roller burnishing process. Precise determination of the depth of the plastically deformed layer is difficult due to slight deformation at the boundary of the plastic and elastic zone, the lack of visible changes in the microstructure, and minimal changes in microhardness. The article shows the method of original measurement method that consists in determining the thickness of the deformed layer using rings. The method involves the profilographometric measurements of the disconnected rings (samples) which are flat-faced in the package on the mandrel. The rings material deforms plastically in the surface layer causing wrapping of the end face of the ring in the direction of the rolling tool movement. After dismantling the ring pack, measurements were made on the face of each ring along radial directions, and the thickness of the deformed layer was observed on the microscope. The method was verified by microhardness measurements in the cross-section and cross-section of the ring. The results of deformation depth measurements were verified by finite-element-based numerical simulation.


2021 ◽  
Vol 7 (4) ◽  
pp. 614-632
Author(s):  
Sayeh Beroual ◽  
Mohamed Laid Samai

The comparison between steel structures and reinforced concrete structures has always been governed by economy and response to earthquake. Steel structures being lighter and are thus more efficient to resist earthquake. On the other hand, they are more expensive (4 to 5 times). Theoretically, two structural elements having the same plastic moment have an equal failure or collapse load. Different profiles of IPE are realized in industry and all their characteristics are determined with a great precision (weight, geometrical characteristics and thus their plastic moment). Determining equivalent rectangular singly reinforced concrete cross-sections is not easy and seems impossible to be solved analytically. To a given profile it may be found a multitude of equivalent rectangular reinforced concrete cross-section (singly and doubly reinforced with different yield strengths and compositions of concrete). To take into consideration all these factors, it is absolutely necessary to construct three axis design charts with an appropriate choice of system of coordinates in order to cover all possible ranges of different parameters. The choice of all these possible rectangular reinforced concrete sections is governed by the plastic performance of these later. They must be under reinforced, allowing plastification of steel before failure in order to permit the redistribution phenomenon in plastic analysis. The exploitation of these different charts has revealed that the absolute majority of these rectangular reinforced concrete cross-section are reasonably well designed and are in conformity with the dimensions used in practice. The results of the present characterization using Eurocode 2 characteristics are compared to those of CP110. The impact does not seem to be very relevant. Doi: 10.28991/cej-2021-03091677 Full Text: PDF


Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as


2003 ◽  
pp. 42-49 ◽  
Author(s):  
E. Bushmin

The article is devoted to the analysis of improving budget process trends. The author offers the concept of "financial technologism". Its usage should promote an essential improvement of the budget process. The given concept is based on the fact that the regulation of budget procedure is the process of determination of "rules of the game", and the order of interaction of different institutions within the framework of the budget process, and the trends and volumes of expenses are the strategy of institutions. The procedure within the budget process plays a principal role as compared with the trends and volumes of public expenditures.


2020 ◽  
Vol 2 (2) ◽  
pp. 08-15
Author(s):  
Rahma Triyana ◽  
Salmi Salmi

Malaria is one of the health problems in Indonesia, especially West Sumatra. Determination of the description of Malaria disease in an area is needed to determine the spread and severity of the disease. This study aims to determine the frequency distribution according to age, sex and place of residence, description of the types of Plasmodium causes of Malaria and hematological features in Malaria patients at Siti Rahmah Padang Hospital in 2018. This type of research is a descriptive observational study with an approach or design cross section (cross sectional). The frequency distribution of Malaria sufferers in Siti Rahmah Padang Hospital in 2018 according to the highest age was in the age group 21-30 years as many as 28 cases (36.8%), the highest sex among men was 46 (60.5%) and the highest number of residences was found in Koto Tangah sub-district there were 31 cases (40.8%). The type of Plasmodium found in Malaria cases in Siti Rahmah Padang Hospital in 2018 was P. vivax (73 cases (96.05%)) and P. falciparum (3 cases (3.95%)). The results of laboratory tests on Hb, hematocrit, platelet and leukocyte levels in Malaria positive patients in Siti Rahmah Padang Hospital in 2018 were in the normal range.


2020 ◽  
Vol 2 (2) ◽  
pp. 08-15
Author(s):  
Rahma Triyana Y ◽  
Salmi Salmi

Malaria is one of the health problems in Indonesia, especially West Sumatra. Determination of the description of Malaria disease in an area is needed to determine the spread and severity of the disease. This study aims to determine the frequency distribution according to age, sex and place of residence, description of the types of Plasmodium causes of Malaria and hematological features in Malaria patients at Siti Rahmah Padang Hospital in 2018. This type of research is a descriptive observational study with an approach or design cross section (cross sectional). The frequency distribution of Malaria sufferers in Siti Rahmah Padang Hospital in 2018 according to the highest age was in the age group 21-30 years as many as 28 cases (36.8%), the highest sex among men was 46 (60.5%) and the highest number of residences was found in Koto Tangah sub-district there were 31 cases (40.8%). The type of Plasmodium found in Malaria cases in Siti Rahmah Padang Hospital in 2018 was P. vivax (73 cases (96.05%)) and P. falciparum (3 cases (3.95%)). The results of laboratory tests on Hb, hematocrit, platelet and leukocyte levels in Malaria positive patients in Siti Rahmah Padang Hospital in 2018 were in the normal range.


Author(s):  
Vitaly М. Goritsky ◽  
◽  
Georgy R. Shneyderov ◽  
Eugeny P. Studenov ◽  
Olga A. Zadubrovskaya ◽  
...  

Determination of causes of crack-like defects in the heavy plate steel 09Г2С is a crucial task, the solution of which is aimed at improving the mechanical safety of oil storage steel vertical tanks. In order to determine the causes for the formation of a group of crack-like defects oriented towards rolling, revealed during grinding and magnetic inspection of the tank wall surface near the vertical weld, the analysis of the chemical composition and testing of the mechanical properties of heavy plate steel were carried out, including the determination of the anisotropy of impact toughness in the temperature range from +20 to –75 °С, analysis of metal microstructure in the area of defect formation on transversal sections and rolled surface. Impact bending tests of 09Г2С heavy plate steel after controlled rolling in longitudinal and transverse directions showed no anisotropy of impact toughness, as well as high purity of steel as for sulfur and titanium, which at higher content causes impact toughness anisotropy. The revealed features of metal microstructure near the defects made it possible to conclude that the crack-like defects were formed during the rolling of gas bubbles at the stage of preparing semi-finished rolled products for finishing rolling. One of the possible methods to prevent such defects from getting into finished rolled products is the use of automated systems of visual inspection of rolled products in the manufacturing process.


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