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Abstract

The paper addresses the problem of placement of sectionalizing switches in medium voltage distribution networks. Proper placement of sectionalizing switches is one of the elements leading to higher power networks reliability. The methods of optimal allocation of such switches in a MV distribution network are presented in the paper. SAIDI was used as a criterion for the sectionalizing switches placement. For selecting optimum placements, three methods were used: brute force method, evolutionary algorithm and heuristic algorithm. The calculations were performed for a real MV network.

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Authors and Affiliations

W. Bąchorek
M. Benesz
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Abstract

The paper presents research results of bond tests in completely concrete encased steel Isection columns made of self-compacting concrete (SCC). The results of push-out tests obtained by elements made of SCC were compared with those elements, which were made of vibrated concrete. The influence of selected factors on resistance to the vertical shear was considered in this study. The analysis of research results shows that the resistance to the vertical shear between steel I-section and SCC concrete depends on distance between stirrups and concrete age. Shrinkage has important influence on interfacial bond forces. The test results were compared with a recommendations given in the Design code – Eurocode 4. This standard can be used only for composite elements made of lightweight and vibrated concrete. In the case of completely concrete encased I-section composite columns the shear resistance after 28 days and after concrete shrinkage was higher than design resistance strength given in the standard. This means that the design value of the shear strength given in the standard should be verified and checked, if it can be applied to elements made of SCC concrete. Further tests should be carried out to determine the value of shear resistance for such elements.
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Authors and Affiliations

Magdalena Szadkowska
1
ORCID: ORCID
Elżbieta Szmigiera
1
ORCID: ORCID

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
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Abstract

Global Vector Autoregressive models came to be used quite widely in empirical studies using macroeconomic non-stationary panel data for the global economy. In this paper, it is shown that when the loading matrix of the cointegrating vectors is not block-diagonal and the cross-sectional spillovers of disequilibrium exist, the use of the GVAR model leads to spurious cross-sectional long-run relationships. Moreover, the results of Monte Carlo simulation show that the GVAR model is outperformed by other valid econometric approaches in terms of the maximum likelihood estimator of long-run coefficients, when the cointegrating vectors matrix is block-diagonal.
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Bibliography

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[14] Pesaran M. H., (2006), Estimation and inference in large heterogeneous panels with multifactor error structure, Econometrica 74, 967–1012.
[15] Pesaran M. H., Schuermann T., Weiner S., (2004), Modeling regional interdependencies using a global error-correcting macroeconomic model, Journal of Business & Economic Statistics 22(2), 129–162.
[16] Temizsoy A., Montes-Rojas G., (2019), Measuring the effect of monetary shocks on European sovereign country risk: An application of GVAR models, Journal of Applied Econometrics 22, 484–503.
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Authors and Affiliations

Piotr Kłębowski
1
ORCID: ORCID

  1. University of Łódz, Poland
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Abstract

To study the anti-seismic performance of steel structure under high temperature, the finite element analysis software ABAQUS was used to study the seismic performance of Q235 steel welded box section column at service stage under normal temperature and high temperature fire. The effects of welding residual stress, slenderness ratio, width thickness ratio and axial load level on the hysteretic behavior of columns were analyzed and the stable bearing capacity and hysteretic performance of the column under high temperature were investigated. The results show that the maximum bearing capacity of the column decreases with the increase of the residual stress peak value. With the increase of temperature, a decrease in the maximum bearing capacity of columns under constant axial force and horizontal cyclic load and an increase in the ductility occur.
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Authors and Affiliations

Yadi Fu
1
Xueyu Dai
2
Huidi Zhang
2
Yimin Wang
1

  1. Beijing Construction Engineering Group Co. Ltd, Beijing, China
  2. Department of Civil Engineering, China Agricultural University, Beijing, China
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Abstract

The paper deals with determination of flexural resistance buckling curves for welded I-section steel members made of high strength steel (S 690). In the paper the previously proposed BF analytical model is used for approximation of FEM results obtained using moderately large deformation shell theory and ABAQUS/Standard software. Final formulation of flexural resistance buckling curves is possible through the use of the Merchant-Rankine-Murzewski approach adopted extensively in the authors’ previous papers. For nonlinear optimization, which is needed for analytical model parameters determination, the Wolfram Mathematica package is used. Obtained results for S 690 steel are presented against the results for S 355 steel.

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Authors and Affiliations

M.D. Gajewski
M.A. Giżejowski
R.B. Szczerba
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Abstract

The study investigates the axial load behaviour of concrete filled battened steel columns not covered by the design standards. A series of full scale tests on two I-sections connected together with intermediate batten plates and filled with concrete were carried out. The main parameters varied in the tests are length of the members and strength of the concrete filling. One bare steel member was also tested and results were compared with those filled with concrete. The tests results were illustrated by load-strain curves. The main objectives of these tests were twofold: first, to describe behaviour of new steel-concrete columns and second, to analyze the influence of slenderness on load-carrying capacity.

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Authors and Affiliations

M. Siennicki
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Abstract

Promoted by many cities to meet the commute needs of their residents (for work, education, etc.), urban rail transport is a spatially expanding system. The safety of rail passengers and road users is one of the most important factors to consider when designing the infrastructure and assessing the operation of the urban tram system. One of the unsolved issues in the functioning of tram transport are sections of tramways with large longitudinal slopes. The article presents an attempt to use risk management for assessing the operational safety of tramways located on road sections with large longitudinal gradients. This particular problem occurs on a tram route in Gdansk. It runs along a street (partly on an overpass) with a gradient above 5% and a small horizontal curve. Risk was assessed using TRANS-RISK, a risk management method. In the first stage, a risk analysis was carried out using the Bow–Tie methods and error trees. The main risks of serious accidents on the analysed section of the tramway were identified. Three sub-concepts were used to assess risk: individual, societal and collective. Although not generally used for assessments of urban transport infrastructure, the latter was found most useful for assessing the safety of the analysed infrastructure. The results of the analyses and assessments helped to formulate design and maintenance principles for tram infrastructure located on sections with steep gradients.
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Bibliography

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[5] V. De Labonnefonm and J.M. Passelaigue, “Analysis of reported events – year 2012 – evolution 2004–2012”, Tram Division, Ministère de l’Écologie, de l’Énergie, Paris, 2014.
[6] S. Dindar et al., “Derailment-based fault tree analysis on risk management of railway turnout systems”, IOP Conference Series: Materials Science and Engineering, vol. 245, no. 4, 2017. DOI: 10.1088/1757- 899X/245/4/042020.
[7] “Największa katastrofa tramwajowa w historii Polski wydarzyła się w Szczecinie, 48 rocznica”, Gazeta Wyborcza. pl, 07 grudzien 2015.
[8] K. Jamroz, et al., “Trans-Risk – An integrated method for risk management in transport”, Journal of KONBiN, vol. 1, no. 13, 2010. DOI: 10.2478/v10040-008-0149-9.
[9] K. Jamroz, “Metoda zarz˛adzania ryzykiem w inzynierii drogowej” (in Polish), “Method of risk management in highway engineering”, Wydawnictwo Politechnika Gdanskiej, Gdansk, Poland, 2011.
[10] K. Jamroz, et al., “Analiza i ocena bezpieczenstwa ruchu tramwajowego na estakadzie tramwajowej w ulicy Rakoczego w Gdansku”, Raport, Politechnika Gdanska, Fundacja Rozwoju Inzynierii Lądowej, Gdansk 2015.
[11] K. Jamroz, et al., “Audyt bezpieczenstwa ruchu tramwajowego w Gdansku w ramach zadania, Dokumentacja dla przyszłych projektów”, Raport, Fundacja Rozwoju Inzynierii L˛adowej, Transprojekt Gdanski, TRAFIK, Gdansk 2017.
[12] A Kadzinski, “Studium wybranych aspektów niezawodnosci systemów oraz obiektów pojazdów szynowych”, Politechnika Poznanska, Rozprawy nr 511, Poznan 2013.
[13] A. Kobaszynska-Twardowska, “Zarządzanie ryzykiem zagrozeń na przejazdach kolejowych”, Praca doktorska, WydziałMaszyn Roboczych i Transportu, Politechnika Poznanska, Poznan 2017.
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[16] Z. Konopacki-Maciuk, “Trams as tools of urban transformation in French cities”, Technical Transactions Architecture, vol. 10-A, 2014.
[17] L. Menetrieux, “Tram accidents’ analysis – France”, STRMTG, French Guided Transport Technical Service –Ministère de l’Écologie, de l’Énergie, Paris 2011.
[18] RAIB, “Rail accident report: Overturning of a tram at Sandilands junction”, Croydon 9 December 2016. Report 18/2017, December 2017.
[19] NSW Government: Transport Roads and Traffic Authority, “Railway crossing safety series. Evaluate: Applying the railway crossing cause consequence bow tie models”, RTA/Pub. 11.377, Roads and Traffic Authority of New South Wales, Australia, 2011.
[20] J. Szmaglinski, S. Grulkowski, and K. Birr, “Identification of safety hazards and their sources in tram transport”, 12th International Road Safety Conference GAMBIT 2018, Gdansk, Poland MATEC Web of Conferences, vol. 231, 2018. DOI: 10.1051/matecconf/201823105008.
[21] V. Trbojevic, “Risk criteria in EU. Advances in safety and reliability”, Taylor and Francis Group, London 2005.
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[23] A. Kahlouche and R. Chaib, “Analysis of the tram safety: case study of Algeria”, Procedia Engineering, vol. 178, pp. 401–408, 2017. DOI: 10.1016/j.proeng.2017.01.076.
[24] M. Schmitz, Ch. Hessel, and U. Stahlberg, “Operation of autonomous tramways”, Verband Deutscher Verkehrsunternehmen e. V.(VDV), Position paper, Cologne, Germany, August 2019.
[25] M. Teixeira, J. Baptista, and C. Gaïvoto, “Operation and safety of tramways in interaction with public space”, COST – European Cooperation in Science and Technology, TU1103 Action final report, September 2015.

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Authors and Affiliations

Kazimierz Jamroz
1
ORCID: ORCID
Sławomir Grulkowski
1
Krystian Birr
1
ORCID: ORCID
Łukasz Jeliński
1
ORCID: ORCID
Marcin Budzyński
1
ORCID: ORCID

  1. Gdansk University of Technology, Faculty of Civil and Environmental Engineering, Narutowicza 11/12, 80-233 Gdansk, Poland
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Abstract

The web-tapered I-columns have the capacity to resist the flexural buckling and lateral torsional buckling at a particular location where as in the rest of the member the capacity is lower. There needs a focusing on the nonprismatic members, to find the buckling capacity and standard procedures are to be framed in Indian Code IS 800:2007. This exploratory research explores simulated finite element models covering a total of 60 web tapered column sections having taper ratios (h2/h1) from 1.0 to 3.0 using FEA software ANSYS17.2. With an elaborate Eigenvalue buckling analysis, this research has come up with newer design equation for calculating the buckling load of web tapered I columns. This novel equation could predict the buckling stress for any taper ratio of web tapered I column of any length.

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Authors and Affiliations

C. Rameshbabu
S. Prabavathy
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Abstract

In the paper experimental investigation results of three elements are presented. Two of them were made of reinforced concrete. The strengthened bracket had the steel accessory mounted to cracked loaded corbel (while it was loaded to half ultimate force of the reference element), the reference one was tested without any accessory. The third corbel was the steel accessory mounted to the concrete column. Full scale corbels were 450 mm deep and 250 mm wide, steel accessory was 320 mm high. The aim of the research was to verify the following thesis: short corbels (shear slenderness ac /h ≈ 0,3) can be strengthened by a steel accessory. Load carrying capacity of strengthened member increased by 40 %. The ultimate force obtained for the steel accessories mounted to concrete column was 66 % of reference value. While testing some observations and measurements (strain of reinforcement and concrete, development of cracking) were made which allowed to describe corbel behaviour under increasing load.

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Authors and Affiliations

T. Urban
Ł. Krawczyk
M. Gołdyn
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Abstract

This paper is entirely devoted to practical aspects of direct design and assessment of safety and serviceability of steel planar framework using advanced analysis. The development of advanced analysis has been driven by a desire for a more accurate representation of the behaviour of planar framework by considering the beam and spring numerical modelling technique together with plasticity and geometrically nonlinear effects as well as structural imperfections accounted for. The validated 2D version of CSD advanced analysis developed by the author is used in this paper for its practical application towards the resistance and serviceability assessment of existing simple construction framework. This steel braced frame was a subject of technical expertise. The same structure geometry but with different joint detailing is then considered to show how the effect of joint properties may affect the braced frame performance. Results of investigations are presented in the form of frame global response at both the ultimate limit state and the serviceability limit state, and also in the form of member local responses. Conclusions with regard to general design and assessment practice are drawn.

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Authors and Affiliations

A.M. Barszcz
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Abstract

One of the most hazardous places in mines are longwall areas. They emit a considerable amount of methane to the ventilation air. The emission depends on many but mostly known factors. The article presents the research results on changes in the methane concentration along the longwall excavations and longwall. The distributions were obtained based on a measurement experiment at the ZG Brzeszcze mine in Poland. The author’s research aimed to experimentally determine the concentration of methane as a function of the length of excavation for the longwall excavations and longwall. As a result, methane concentration trends along the excavations were obtained. The conclusions show the pros and cons of the method used, and it allows to set the right direction in the development of measurement systems and sensors.
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Bibliography

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[3] M . Li, Y. Liu, Underground Coal Mine Monitoring with Wireless Sensor Networks. ACM Trans. Sen. Netw. 5, 1-29 (2009). DOI : https://doi.org/10.1145/1498915.1498916
[4] L . Liao, G. Lou, M. Chen, An Integrated RFID and Sensor System for Emergency Handling in Underground Coal Mines Environments. In J. Zheng, S. Mao, S.F. Midkiff, H. Zhu, (Eds.); Ad Hoc Networks, Springer Berlin Heidelberg 28, 818-824 (2010). DOI : https://doi.org/10.1007/978-3-642-11723-7_56 [5] F . Ma, Sensor Networks-Based Monitoring and Fuzzy Information Fusion System for Underground Gas Disaster. In Proceedings of the 2012 9th International Conference on Fuzzy Systems and Knowledge Discovery, 596-600 (2012).
[6] M .A. Moridi, M. Sharifzadeh, Y. Kawamura, H.D. Jang, Development of Wireless Sensor Networks for Underground Communication and Monitoring Systems (the Cases of Underground Mine Environments). Tunneling and Underground Space Technology 73, 127-138 (2018). DOI : https://doi.org/10.1016/j.tust.2017.12.015
[7] A . Zagórecki, Application of Sensor Fusion and Data Mining for Prediction of Methane Concentration in Coal Mines. Mining – Informatics, Automation and Electrical Engineering 43, 4 (2015).
[8] H . Zhao, W. Yang, An Emergency Rescue Communication System and Environmental Monitoring Subsystem for Underground Coal Mine Based on Wireless Mesh Network. Int. J. Distrib. Sens. N. 14, (2018). DOI : https://doi.org/10.1177/1550147718805935
[9] Polish Legal Act, Dz.U. 2017 poz. 1118, Rozporządzenie Ministra Energii z Dnia 23 Listopada 2016 r.
[10] A . Tomczyk, K. Rutecki, Monitorowanie i Kontrola Zmian Ciśnienia Atmosferycznego Kopalni dla Potrzeb Bezpieczeństwa. Mechanizacja i Automatyzacja Górnictwa 47, 7, 99-107 (2009).
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[14] J. Kruczkowski, Rozkład Stężeń Metanu w Wyrobiskach Przyścianowych. In Zagrożenia aerologiczne w kopalniach węgla kamiennego – profilaktyka, zwalczanie, modelowanie, monitoring; Główny Instytut Górnictwa (2013).
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Authors and Affiliations

Piotr Ostrogórski
1
ORCID: ORCID
Przemysław Skotniczny
1
ORCID: ORCID
Mieczysław Pucka
2

  1. Strata Mechanics Institute, Polish Academy of Sciences, 27 Reymonta Str., 30-059 Kraków, Poland
  2. Tauron Wydobycie S.A. ZG Brzeszcze, ul. Kościuszki 1, 32-620 Brzeszcze, Poland
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Abstract

The content of this paper is dedicated to the analysis of the flat planarity of forklift stacker’s track and cross sections of lanes between racks in a warehouse. These results will serve as a basis for a possible reconstruction of the track and racks and shall contribute to the overall reduction of costs related to an unexpected bad technical condition. The contribution aims to assess the geometric parameters of warehouse racks at the selected company operation in terms of their suitability for further use. The choice of the selected topic represents a relevant issue, which can be possibly encountered in daily practice related to the storage and transport processes of products. The measurements and processing of longitudinal profiles and cross-sections were made in the local coordinate and local vertical system. Points on the lower, middle and upper level of racks were measured for good and correct interpretation of results. Testing the measured positional change of poles is on the end of this paper. The immediate readiness of interest groups of subjects for adopting necessary actions to ensure the stability and safe operation of the whole network of lanes of the warehouse spaces is the expected contribution of the presented results.

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Authors and Affiliations

Slavomír Labant
Marcela Bindzárová Gergel’ová
Štefan Rákay
Erik Weiss
ORCID: ORCID
Jozef Zuzik
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Abstract

The performance of ten wickless heat pipes without adiabatic sections is investigated experimentally at low heat inputs 120 to 2000 W/m2 for use in solar water heaters. Three heat pipe diameter groups were tested, namely 16, 22, and 28.5 mm. Each group had evaporator lengths of 1150, 1300, and 1550 mm, respectively, with an extra evaporator length of 1800 mm added to the second group. The condenser section length of all heat pipes was 200 mm. Ethanol, methanol, and acetone were utilized as working fluids, at inventory of 25%, 50%, 70%, and 90% by evaporator volume respectively. The 22 mm diameter pipes were tested at inclination angles 30◦, 45◦, and 60◦. Other diameter groups were tested at 45◦ only. Experiments revealed increased surface temperatures and heat transfer coefficients with increased pipe diameter and evaporator length, and that increased working fluid inventory caused pronounced reduction in evaporator surface temperature accompanied by improved heat transfer coefficient to reach maximum values at 50% inventory for the selected fluids. Violent noisy shocks were observed with 70% and 90% inventories with the tested heat pipes and the selected working fluids with heat flux inputs from 320–1900 W/m2. These shocks significantly affected the heat pipes heat transfer capability and operation stability. Experiments revealed a 45◦ and 50% optimum inclination angle of fill charge ratio respectively, and that wickless heat pipes can be satisfactorily used in solar applications. The effect of evaporator length and heat pipe diameter on the performance was included in data correlations.

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Authors and Affiliations

Hassan Naji Salman Al-Joboory
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Abstract

In the current work the calculations of the reaction cross-section of total fusion σ fus, the fusion barrier distribution D fus, and the probability P fus were achieved for systems ⁶He+⁶⁴Zn, ⁸B+⁵⁸Ni and ⁸He+¹⁹⁷Au which involve halo nuclei by using a semiclassical approach. The semiclassical and quantum mechanics treatments comprise the approximation of WKB for describing the relative motion among projectile nuclei and target nuclei, and the method of CDCC (Continuum Discretized Coupled Channel) for describing the intrinsic motion for the projectile and target nuclei. Our semiclassical calculations yielded findings that were compared to obtainable experimental data as well as quantum mechanics calculations. For fusion cross-sections σ fus below and above the Coulomb barrier Vb, the quantum mechanics coupled channels are very similar, according to the experimental results.
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Bibliography

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Authors and Affiliations

Maryam H. Abd Madhi
1
Fouad A. Majeed
1
ORCID: ORCID

  1. Department of Physics, College of Education for Pure Sciences, University of Babylon, Babylon, Iraq
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Abstract

This article re-examines the material collected by the RFE Audience Research Department between 1958 and 1961 among Polish refugees and temporary visitors from Poland in the West. The aim of this analysis is to gain fresh insight into the attitudes and opinions about the Polish Section of the Radio Free Europe expressed by its listeners

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Authors and Affiliations

Kamila Kamińska-Chełminiak
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Abstract

This study investigates mechanical properties of accelerated cooled and self-tempered (AC-ST) H-type S275JR quality steel sections in HEA120 and HEB120 sizes. The cooling process is conducted with a specially manufactured system that sprays a coolant consisting of a water + compressed air mixture on the section surfaces. Cooling times were applied as 10 and 30 seconds using 4 and 12 bar compressed air + water at an average constant pressure of 5 bar and a constant flow rate of 0.08 kg/s. In the HEA120 sections, the highest cooling rate was obtained with 83°C/s in the web region under the cooling time of 30 s and the air pressure cooling condition of 12 bar. At the cooling rate up to 6°C/s, the microstructure is transformed to acicular ferrite and polygonal ferrite phase from Ferrite+Pearlite. But upper bainite phase was formed at a cooling rate of 30°C/s, and a small amount of martensite and lower bainite microstructures were observed at a cooling rate of 60°C/s and above. The hardness in the untreated sections, in the range of 106-120 HB, was increased to 195 HB at a cooling rate of 83 C/s in the web region of the HEA120 section. For a cooling rate of 23°C/s, the maximum compressive residual stresses of –352 MPa are measured in the crotch region of the HEB120. And for a cooling rate of 6°C/s, the maximum tensile residual stresses of 442 MPa were determined in the flange region of the HEA120 section.
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Authors and Affiliations

A. Işıkgül
1
ORCID: ORCID
H. Ahlatci
2
ORCID: ORCID
İ. Esen
3
ORCID: ORCID
Y. Türen
2
ORCID: ORCID
O. Yağız
2
ORCID: ORCID

  1. Karabük Iron Steel Industry Trade and Co. Inc., Research and Development Department, Karabük, Turkey
  2. Karabük University, Department of Metallurgy and Materials Engineering, Karabük, Turkey
  3. Karabük University, Department of Mechanical Engineering, Karabük, Turkey
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Abstract

Elastic lateral-torsional buckling of double-tee section structural steelworks has been widely investigated with regard to the major axis bending of single structural elements as a result of certain loading conditions. No specific attention has been paid to the general formulation in which an arbitrary span load pattern was associated with unequal end moments as a result of the moment distribution between structural members of the load bearing system.Anumber of analytical solutionswere developed on the basis of the Vlasov theory of thin-walled members. Since the accurate closed-form solutions of lateral-torsional buckling (LTB) of beams may only be obtained for simple loading and boundary conditions, more complex situations are treated nowadays by using numerical finite element methods (FEM). Analytical and numerical methods are frequently combined for the purpose of: a) verification of approximate analytical formulae or b) presentation the results in the form of multiple curve nomograms to be used in design practice. Investigations presented in this paper deal with the energy method applied to LTB of any complex loading condition of elements of simple end boundary conditions, bent about the major axis. Firstly, a brief summary of the second-order based energy equation dealt with in this paper is presented and followed by its approximate solution using the so-called refined energy method that in the case of LTB coincides with the Timoshenko’s energy refinement. As a result, the LTB energy equation shape functions of twist rotation and minor axis displacement are chosen such that they cover both the symmetric and antisymmetric lateral-torsional buckling modes. The latter modes are chosen in relation to two lowest LTB eigenmodes of beams under uniform major axis bending. Finally, the explicit form of the general solution is presented as being dependent upon the dimensionless bending moment equations for symmetric and antisymmetric components, and the in-span loads. Solutions based on the present investigations are compared for selected loading conditions with those obtained in the previous studies and verified with use of the LTBeam software. Conclusions are drawn with regard to the application of obtained closed-form solutions in engineering practice.
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Authors and Affiliations

Anna Barszcz
1
ORCID: ORCID
Marian Giżejowski
1
ORCID: ORCID
Malwina Pękacka
2

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
  2. Warsaw University of Technology Graduate, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
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Abstract

The study analysed a bisymmetric closely-spaced built-up member, pin-supported at both ends. Itwas bipolarly pre-stressed with a displacement (BPCSBM), and loaded with an axial compressive force. Maximum internal gap between the chords was assumed in the section, in which during the stability failure in a classic closely-spaced member, the largest lateral displacements between nodes would potentially occur. As regards the BPCSBM chosen for analysis, the issues of the buckling resistance in the presence of compressive axial load were solved using the energy method, in which the functional minimisation was performed in accordance with the Rayleigh–Ritz algorithm. The problem of BPCSBM stability was also solved using FEM. A spatial shell model was developed. The stability analysis was performed. The analysis resulted in obtaining the buckling load and the member buckling modes. A general conclusion was formulated based on the results obtained: bipolar pre-stressing leads to an increase in buckling resistance of closely-spaced members.
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Authors and Affiliations

Monika Siedlecka
1
ORCID: ORCID

  1. Kielce University of Technology, Faculty of Civil Engineering and Architecture, Al. Tysiaclecia PP 7, 25-314 Kielce, Poland
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Abstract

Elastic instability of steel I-section members has been investigated with regard to axial compression, major axis bending as well as compression and major axis bending, based on the Vlasov theory of thin-walled members. Investigations presented in this paper deal with the energy method applied to the flexural-torsional buckling (FTB) problems of any complex loading case that for convenience of predictions is treated as a superposition of symmetric and antisymmetric components. Firstly, the review of energy equation formulations is presented for the elastic lateral-torsional buckling (LTB) of beams, then the most accurate beam energy equation, so-called the classical energy equation formulated for bisymmetric I-section beams is extended to cover also the beam-column out-of-plane stability problems, referred hereafter to FTB problems. Secondly, for the simple end boundary conditions, the shape functions of twist rotation and minor axis displacement are chosen such that they cover both symmetric and antisymmetric lateral-torsional buckling modes in relation to two lowest eigenvalues of the beam LTB in major axis bending. Finally, the explicit form of the general solution is presented being dependent upon the dimensionless bending moment equations for symmetric and antisymmetric components, and the load factor where the lower k index identifies the load case.
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Authors and Affiliations

Marian Antoni Giżejowski
1
Anna Maria Barszcz
1
Zbigniew Stachura
2

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
  2. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw
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Abstract

Steel prismatic elements of equal flanges double-tee section subject to major axis bending and compression, unrestrained in the out-of-plane direction between the supports, are vulnerable to buckling modes associated with minor axis flexural and torsional deformations. When end bending moments are acting alone on the quasi-straight member, the sensitivity to lateral-torsional buckling (LTB) is very much dependent upon the ratio of section minor axis to major axis moments of inertia, and additionally visibly dependent upon the major axis moment gradient ratio. In the case of major axis bending with the presence of a compressive axial force, even of rather small value in relation to the section squash resistance, there is a drastic reduction of structural elements in their realistic lengths to maintain a tendency to fail in the out-of-plane mode, governed by the large twist rotation. Increasing the load effects ratio of dimensionless axial force to dimensionless maximum major axis bending moment, the buckling mode goes away from that of lateral-torsional one, starting to become that closer to the minor axis flexural buckling (FBZ) mode. Different aspects of the flexural-torsional buckling (FTB) resistance of the typical rolled H-section beam-column with regard to the General Method (GM) formulation, developed by the authors elsewhere and based on the parametric finite element analysis, are dealt with in this paper. Investigations are concerned with different member slender ratio, different moment gradient ratios and different load effects ratio. Final conclusions are related to practical applications of the proposed format of General Method in relation to the effect of large displacements on the FTB resistance reduction factor described through the dimensionless measure of action effects and the FTB relative slenderness ratio of quasi-straight beam-columns.
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Authors and Affiliations

Marian Antoni Giżejowski
1
Radosław Bronisław Szczerba
2
Zbigniew Stachura
2
Marcin Daniel Gajewski
2

  1. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
  2. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw
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Abstract

Steel-glulam structure is a new type of composite structure,glulam have lateral support effect on steel plate, that can prevent premature buckling of steel plate and improve the stability of steel structure. In order to study the influence of column’s cross-section form on the seismic performance of steel-glulam composite beam-to-column exterior joint, the column’s cross-section form was taken as the basic variable (glulam rectangular section , H-beam section and H-beam-glulam rectangular section were used respectively). The pseudo-static tests of three composite beam-to-column joints were carried out to observe the different failure modes, and obtain the mechanical performance indexes. The experiment results demonstrated that: The energy dissipation capacity of beam-to-column exterior joint composed of glulam column was the worst, the ultimate bearing capacity and stiffness were the lowest. The ultimate bearing capacity of the exterior joints formed by the H-beam column and the H-beam-glulam composite column were both high, and their ductility coefficients were similar, while the former had better energy dissipation capacity.
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Authors and Affiliations

Shaowei Duan
1
Xinglong Liu
2
Jian Yuan
1
Zhifeng Wang
1

  1. Central South University of Forestry and Technology, College of Civil Engineering, Changsha, Hunan, China
  2. Shenzhen Huayang International Design Group Co., Ltd. Changsha Branch, Changsha, Hunan, China
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Abstract

The issues of local stability and ultimate resistance of a continuous beam with thin-walled box section (Class 4) were reduced to the analysis of the local buckling of bilaterally elastically restrained internal plate of the compression flange at longitudinal stress variation. Critical stress of the local buckling was determined using the so-called Critical Plate Method (CPM). In the method, the effect of the elastic restraint of the component walls of the bar section and the effect of longitudinal stress variation that results from varying distribution of bending moments were taken into account. On that basis, appropriate effective characteristics of reliable sections were determined. Additionally, ultimate resistances of those sections were estimated. The impact of longitudinal stress variation and of the degree of elastic restraint of longitudinal edges on, respectively, the local buckling of compression flanges in the span section (p) and support section (s) was analysed. The influence of the span length of the continuous beam and of the relative plate slenderness of the compression flange on the critical ultimate resistance of box sections was examined.

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Authors and Affiliations

K. Brzezińska
A. Szychowski
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Abstract

The most important challenges in the construction field is to do the experimentation of the designing at real time. It leads to the wastage of the materials and time consuming process. In this paper, an artificial neural network based model for the verification of sigma section characteristics like shear centre and deflection are designed and verified. The physical properties like weight, depth, flange, lip, outer web, thickness, and area to bring shear centre are used in the model. Similarly, weight, purlin centres with allowable loading of different values used in the model for deflection verification. The overall average error rate as 1.278 percent to the shear centre and 2.967 percent to the deflection are achieved by the model successfully. The proposed model will act as supportive tool to the steel roof constructors, engineers, and designers who are involved in construction as well as in the section fabricators industry.

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Authors and Affiliations

S. Janani
R. Thenmozhi
L.S. Jayagopal

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