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Summary: This paper compares the procedures for calculating steel plate girders according to thе current standards ЕN1993-1-5: 2006 [1] and the new version prEN1993-1-5: 2020, which is in the final stage of development [2]. There is a particular emphasis on problems of resistance to patch loading, the interaction between transverse force, bending moment and shear force, and the reduced stress method. The differences between the current standard and the new version prEN1993-1-5: 2020 [2] are illustrated using specific numerical examples.

Rad prikazuje merenje početnih geometrijskih imperfekcija i zaostalih napona u okviru istraživanja nosivosti centrično pritisnutih elemenata L poprečnog preseka od nerđajućeg čelika. Istraživanjem su obuhvaćena tri različita tipa L profila – hladnooblikovani, vrućevaljani i laserski zavareni. Postupak i rezultati merenja početnih geometrijskih imperfekcija primenom sistema za lasersko merenje prezentovani su u radu. Merenje zaostalih napona metodom sečenja sprovedeno je na vrućevaljanom i laserski zavarenom uzorku nominalnih dimenzija 100 × 100 × 10, napraveljenih od austenitnog nerđajućeg čelika EN 1.4301. Postupak merenja zaostalih napona i rezultati u formi rasporeda zaostalih napona i ekstremnih vrednosti prikazni su u radu. The paper presents initial geometric imperfections and residual stresses measurment as a part of a research on ultimate capacity of axially compressed angle columns made from stainless steel. The research covers three different angle types – cold-formed, hot-rolled and laser-welded. The procedure and results of initial geometric imperfections measurments using a laser measurement system are presented. Measurement of residual stresses using a sectioning method was performed on hot-rolled and laser-welded samples with nominal dimensions of 100 × 100 × 10, made of austenitic stainless steel EN 1.4301. The procedure of residual stresses measurement and obtained results in form of residual stresses distribution and extreme values are presented.

Stainless steel sections are used for structures in aggressive environments where the greater material cost can often be justified in return for longer maintenance-free periods, for example in the water treatment, nuclear, petrochemical and food and beverage sectors. This paper presents a comparative imperfection sensitivity study of hot-rolled and laser-welded pin-ended equal angle columns made of austenitic stainless steel grade 1.4301. Although the initial geometric imperfections in these structural elements are similar, there is a difference in the initial stress state due to the different manufacturing processes. The study includes three-dimensional geometric imperfection measurements conducted by a laser scanner, and, in parallel residual stress measurements performed by the sectioning method using water jet cutting. The overall bow, camber, and twist imperfections are determined from the scanned specimens. In addition, the shapes of the residual stress patterns through the thickness of the angle leg are shown. Based on the findings related to imperfection distributions and amplitudes, a FE analysis is performed both on hot-rolled and laser-welded angles to study the influence of the variability of initial imperfections on compression resistance. The separate and combined effects of the measured residual stresses and initial out-of-straightness are considered and the reduction in the buckling resistances of initially straight angle columns is determined. The structural responses of hot-rolled and laser-welded columns are compared and discussed.

This paper presents parametric linear-elastic analysis of flexural buckling of idealised non-uniform member and nonlinear analysis of flexural buckling with equivalent imperfections, using software package Abaqus. The analysis includes hinged and cantileverstepped members, where the stiffness ratio of the upper and lower segments and the ratio of the values of axial forces at the top and at the change in the cross-section are varied. The aim of this paper is to define graphic and table models for determining effective lengths coefficients of non-uniform members' segments based on a relevant and reliable database that was obtained using the Finite element method. In addition, the reliability of the method for calculating the flexural stability of the compressed columns according to EC3 was evaluated in which the critical load value was determined in the previous step using the Elastic buckling analysis of idealised elements. Rad prikazuje parametarsku linearno-elastičnu analizu fleksionog izvijanja idealizovanog neuniformnog elementa i nelineranu analizu fleksionog izvijanja sa ekvivalentnim geometrijskim imperfekcijama, urađenu u programu Abaqus. Analizom su obuhvaćeni zglobno oslonjeni i konzolni elementi sa stepenastom promenom poprečnog preseka, kod kojih je variran odnos krutosti gornjeg i donjeg segmenta i odnos vrednosti aksijalnih sila na vrhu i na mestu promene preseka. Rezultat rada je definisanje grafičkih i tabelarnih modela za određivanje koeficijenata dužine izvijanja segmenta neuniformnih elemenata na osnovu relevantne i pouzdane baze podataka koja je dobijena primenom Metode konačnih elemenata. Kao dodatak, ocenjena je pouzdanost metode proračuna fleksione stabilnosti pritisnutih stubova prema EC3 u kojoj je vrednost kritične sile izvijanja određena u prethodnom koraku primenom Elastične analize izvijanja idealizovanog elementa.

Continuous strength method is a contemporary approach to calculation of resistance of stainless steel cross-sections which has been recently developed at the Imperial College of London. The basis of the method is the continuous relation between the slenderness and strain capacity of a cross-section, nonlinear relation between the stress and strain and the strengthening effects of cold forming. In the paper are presented the fundamental rules for calculation of cross-section resistance according to continuous strength method; the comparative analysis of design resistance of the compressed cross-section was conducted through a numerical example according to this method and EN 1993-1-4.

Today, wind power is second largest available renewable resource of energy, after sun and before geothermal and hidrologic energy resources. According to data from 2008. for expected bulding of wind farms with capacity 27 GW it is required to pay 1,35 million euro per MW. The construction of steel tower is about 15-20% of total investment so construction of wind farms is great opportunity for development of civil engineering industry. The aim of this paper is to introduce civil engineers with the specific problems of design of steel towers for wind turbines.

Stainless steels get wider application in engineering structures. Apart from many advantages such as corrosion and fire resistance this material has some special characteristics in compare to regular carbon steels. In this paper short preview of basic characteristics of stainless steels, as also the design procedure according to latest European code, EN 1993-1-4, is shown. . Nerđajući čelici nalaze sve veću primenu u građevinarstvu. Pored niza prednosti kao što su otpornost na koroziju i poboljšana vatrootpornost, ovaj materijal odlikuju i određene specifičnosti u odnosu na klasične ugljenične čelike. Ovaj rad daje kratak prikaz osnovnih karakteristika nerđajućih čelika, kao i postupke proračuna prema najnovijem evropskom propisu, EN 1993-1-4. .

In this paper theoretic basis of design of class 4 cross section in axial compression according to EN1993-1-5 is given. Design procedure is given as an flow chart and ilustrated with an worked example. Plate buckling is treated localy and globaly through the concept of effective cross sections. Interaction between plate-like and column-like behaviour of panels is carried out thought buckling reduction factors and final effective area of cross section.