bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Dynamic and Buckling Behaviour of Steel Cold‐formed Polygonal Conic Pole for Antennas Support
Authors: de Miranda Batista Eduardo , de Lazzari João Alfredo , Matsubara Gustavo Yoshio , Pfeil Michèle 
Published: September 2022

AbstractSupport for antennas placed as high as 40‐50m demands traditional trussed steel or pole towers, the former with much larger base area than the later and the consequences for the costs of the ground occupancy. This aspect is of upmost importance for both urban and rural areas and the reason for the development of higher steel poles with polygonal cross‐section, searching for slender thin‐walled structures. The present research focus is cold‐formed steel conic twenty‐sided polygon solution allowing 40‐50m high antenna support, for which one must deal with the following challenges: (i) wind‐induced dynamic behavior, (ii) buckling analysis, (iii) localized stress concentration close to the openings along the pole, (iv) connection solution that strongly affects the erection procedure and (v) the fatigue effect. Beyond these aspects, results of the dynamic behavior, elastic buckling, nonlinear structural behavior until the collapse and design procedures for the computation of the structural strength of the steel pole are presented and commented, revealing the importance of structural analysis by combining tailored numerical tools as the finite strip and the finite element methods, as well as frequency domain methods for smooth and turbulent wind actions. Additional CFD and experimental wind tunnel results should be considered for advanced structural design, as well as experimental structural analysis to confirm the set of numerical results and the design procedures adopted for the steel polygonal poles.
Experimental and Numerical Investigations on the Moment Capacity and Stability of Z‐shaped Steel Piles
Authors: Enders Alexander , Kuhlmann Ulrike 
Published: September 2022

AbstractHarbour structures like quay walls or construction pit walls in civil engineering are often built up with steel sheet piles. Aside of U‐steel sheet piles also Z‐shaped piles with interlocks are widely used in such structures. The pressure on costs and efficiency and the competition in this field lead to the necessity of increased efficiency in design. To benefit from the potentials in the bending moment capacity of semi‐compact Z‐shaped steel sheet piles forming the infills of combined walls, four‐point‐bending tests were carried out by the Institute of Structural Design at the Materials Testing Institute in Stuttgart in 2019. A FE‐model was validated by back‐calculating the tests, followed by an extensive parametric study (GMNIA) with different Z‐piles. Among others the different geometries, which lead to different b/t‐ratios and the steel grade were varied leading to a different compression flange slenderness. In addition, the lock state was varied to investigate the impact on the bending moment capacity as: Free lock rotation, crimped interlocks with different crimping densities and fully welded over the entire length. Three resistance models were investigated and evaluated for further development of Eurocode 3 Part 5. The FE model was simplified and further developed for stability analyses. This was followed by a parametric study aimed to investigate the stability of Z‐shaped steel sheet piles under axial loads.
Experimental Studies on the Influence of Different Support Conditions and Structural Systems for the Lateral Torsional Buckling Behaviour of Steel Structures
Authors: Jörg Fabian , Bours Anna‐Lena , Winkler Rebekka , Kuhlmann Ulrike , Knobloch Markus 
Published: September 2022

AbstractThe use of slender steel members promotes the competitiveness of steel structures in structural engineering. However, it requires an efficient design, especially for the stability behaviour including lateral torsional buckling which is usually verified by the simplified design method with reduction factors. This method is based on the model of a simply supported member with ideal fork boundary conditions at the ends. However, commonly used joints in engineering practice, such as typical main and secondary beam joints, deviate from the idealisations of these ideal fork restraints. And at system level, there are only a few simply supported members, more common are structural systems such as continuous girders or frames. So far, there is a lack of knowledge on the influence of common joints used in engineering practice and structural system effects on the load‐bearing capacity. This paper deals with the results of experimental studies carried out within a German national (FOSTA) research project. The lateral torsional buckling behaviour of different support and boundary conditions as well as structural systems is investigated for hot‐rolled steel members with doubly and mono‐symmetric sections. In total, 14 tests on support conditions are carried out at the University of Stuttgart and 20 tests on two‐span members at the Ruhr‐Universität Bochum. The aim is to develop easy‐to‐use design rules that consider the effects of realistic conditions and structural system effects on the lateral torsional buckling resistance.
Contribution to Lateral Torsional Buckling of Girders with Rotational Restraints
Authors: Müller Andreas , Taras Andreas 
Published: September 2022

AbstractThe instability case of lateral torsional buckling (LTB) under bending load My is known to be of decisive importance in the design of beams with open cross‐sections. This instability case is expressed by a lateral displacement and simultaneous torsion (or twisting) of the member axis. The restraint of one or both of these deformation components represents an effective and practice oriented method to stabilize beams against LTB. In practice, therefore, use is made of regulations from the current version of EN 1993‐1‐1:2010, Annex BB, which allow for the consideration of the stabilizing effect of continuous and planar components directly connected to the compression chords of the beams. This paper presents the results of a study that investigated the effects of the innovations introduced in the draft standard for the 2nd generation of EN 1993‐1‐1 for the LTB verification of beams with I and H cross‐sections on the regulations for the calculation of the minimum stiffness of a rotational restraint to avoid LTB. In the first part of the paper, the background of the existing and new regulations is discussed together with previous proposals for adapting the definition of the minimum rotation restraint. In addition, a comparison is made with current specifications for the minimum rotational stiffness contained in the National Annex of DIN EN 1993‐1‐1. Subsequently, the regulations of the minimum rotational stiffness in prEN1993‐1‐1, Annex D are assessed.
Simple Structural Models to Compute the Fire Resistance of Restrained Steel Columns using Energy Principles
Authors: Simão Pedro Dias , Rodrigues João Paulo C. 
Published: September 2022

AbstractA simple structural model to represent the behaviour of restrained steel columns in fire is presented. The heat transfer and the mechanical problems are split and the mechanical one is analysed in the temperature's domain, in order to allow the application of any appropriate fire curve. The structural model is composed by two rigid rods connected by plastic hinges. These respect the bending moments – axial forces interaction and degrade their resistance with heating. At the model's top cross section an axial spring is inserted, to represent the restraining of the surrounding frame to the column's axial elongation, and an axial load is applied in order to model the serviceability loading applied prior to the fire event. In the worst‐case scenario, fire occurs only in the neighbourhood of the analysed column while the surrounding frame remains unaffected. Therefore, both the serviceability load and the restraining spring stiffness remain constant throughout the fire event. Longitudinal temperatures gradients are accounted for. Both pinned‐pinned and clamped‐clamped boundary conditions are considered, to assess the influence of the column's statical indeterminacy on its fire resistance. Equilibrium is obtained by means of energy balance: when the temperature rises, the variation of the work produced by the serviceability load equals the variation of the internal strain energy stored at the restraining spring plus the variation of the energy dissipated at the plastic hinges. A set of illustrative examples closes the work.
The General Method for the Fire Design of I‐section Web‐tapered Members
Authors: Maia Élio , Couto Carlos , Real Paulo Vila , Lopes Nuno 
Published: September 2022

AbstractThe General Method of EN 1993‐1‐1 covers the safety verification of non‐prismatic members, as the variable geometry precludes the use of the standard verification clauses. However, no specific guidelines are provided in the fire part of the Eurocode 3 (EN 1993‐1‐2) regarding its implementation at elevated temperatures, apart from adopting the reduction factors for steel material properties. Previous investigations by the authors have demonstrated that the methodology is unsafe for the verification of tapered columns and overly conservative for beams at elevated temperatures, leading to proposals for the calibration of the GM for these members in fire following the design philosophy of the Eurocode 3.The present investigation will start by discussing the latest developments on the validation of the GM for the safety check of tapered members in fire, with particular emphasis on the recently proposed interaction factor for the flexural and lateral‐torsional interaction buckling of tapered beam‐columns. Then, based on the results from the numerical parametric studies, the practical implications of the upcoming revision of the EN 1993‐1‐1 on the safety check of these members with the General Method will be discussed.
The Annealing Effect of Welding on the Strength of Cold‐worked Stainless Steel
Authors: Walport Fiona , Zhang Ruizhi , Meng Xin , Gardner Leroy 
Published: September 2022

AbstractCold‐working can occur during the production of flat sheet products and the fabrication of structural cross‐sections. In both cases, when the material is cold‐worked, plastic deformations result in material strength enhancements. These strength enhancements are particularly significant for materials such as stainless steel, which exhibit rounded stress‐strain behaviour and pronounced strain hardening, and for hollow cross‐sections, where the strength increases arise in both the corner and flat regions of the cross‐section. Numerous studies have shown the importance of utilising this strength enhancement in design, and expressions to predict the strength enhancements have been established. However, if cold‐worked material is welded, some enhanced strength can be lost due to partial annealing in the heat affected zone (HAZ). The extent of this strength loss is investigated experimentally herein. The experimental programme comprised ten tensile coupon tests, with central welds parallel and transverse to the direction of cold‐rolling, as well as twelve full cross‐section tensile tests. Digital imaging correlation was utilised to determine the local constitutive properties of the base metal, the HAZ, and the weld metal. The microhardness and microstructure of the welded coupons, along with the widths of the weld and HAZ, were also characterised.
Dimensioning Aids for Stiffened and Unstiffened Plates According to Eurocode 3 Part 1‐5
Authors: Hulm Felix , Kreutz Johannes , Maier Nadine , Mensinger Martin , Ndogmo Joseph 
Published: September 2022

AbstractIn Germany stiffened plate in bridge construction must be verified using the method of reduced stresses (MRS) according to DIN EN 1993‐1‐5 [2, 3]. Unstiffened plates on the other hand may be verified either according to the effective widths method or according to the reduced stress method. In order to shorten the time‐consuming verification of the standardised verification formats for pre‐dimensioning which is particularly prevalent for stiffened plates diagrams are developed and presented in the present paper on the basis of the MRS by reformulating the buckling verification which enable a quick pre‐dimensioning. With the diagrams, the dimensioning of plate thicknesses and stiffener spacings can be carried out in a few simple and comprehensible steps. The diagrams are selected on the basis of the geometry parameters .a, b. and t or the applicable boundary conditions. For stiffened plate, the maximum permissible spacing of the longitudinal stiffeners or the required main plate thickness can be determined. Diagrams for the dimensioning of longitudinal stiffeners by determining minimum stiffnesses are also presented. The minimum stiffnesses are derived from the geometry of the linear buckling shapes of simply stiffened plate.
Imperfection Sensitivity of Cylindrical Shells Under Shear Loading
Authors: Azizi Esmaeil , Stranghöner Natalie 
Published: September 2022

AbstractOne of the basic load cases relevant for the design of shell structures is torsion, which can occur exemplary in silos and tanks under seismic actions or even under wind loading. To address the stability problem of cylindrical shells under this load case, the relevant design standard EN 1993‐1‐6 and the European Recommendation ECCS EDR5 provide simple approaches for the buckling design of cylindrical shells. In order to improve the current hand calculation rules given in the above documents, this numerical study attempts to include the imperfection sensitivity of cylindrical shells subjected to uniform torsion.In the present paper, theoretical, numerical, and experimental results from the literature are reviewed, and new systematic computational analyses and evaluations are introduced regarding the imperfection sensitivity of cylindrical shells under shear loading. For this purpose, a comprehensive computational study was performed using linear and nonlinear buckling analyses on perfect and imperfect shells. Since the influence of imperfections on the buckling strength of cylindrical shells is highly dependent on the imperfection pattern used in the numerical models, nonlinear buckling analyses were performed on imperfect cylindrical shells with three imperfection types: (i) eigenmode‐affine shape from torsion, (ii) longitudinal eigenmode‐affine pattern, and (iii) eigenmode‐affine shape from external pressure.
Austenitic Stainless Steel EBF Subjected to Low and Extremely Low Cycle Fatigue
Authors: Lázaro Lucy , Chacón Rolando 
Published: September 2022

AbstractDissipative zones buildings, in which plastic hinges or plastic strains occur during, for instance, seismic episodes, have been studied for many different types of steel fuse elements. Stainless steel (SS), has attracted attention in this regard due to its high ductility and further studies are needed to determine its performance and usefulness as fuses.The use of SS in the construction industry has represented an advance due to its already known anticorrosive properties in addition to its strength and ductility. However, recent research on cyclic plasticity shows that SS has significant hardening properties, which can be exploited in the use of this material in structural elements to support cyclic loads, such as those occurring during earthquakes.The cyclic plasticity models in SS have been studied with some applications (fatigue, low‐cycle fatigue and extremely low cycle fatigue). Several studies carried out cyclic tests to obtain experimental data, which have been used for numerical models with the utilisation of a combined numerical model of kinematic/isotropic hardening. These studies recommend models to simulate the behaviour of SS under a cyclic load.This work presents an experimental study of the cyclic behaviour of SS when subject to low and extremely low cycle fatigue. Several protocols on tests such as companion, multiple step and arbitrary tests were carried out. The results inferred from the experimental program provide hardening parameters used to study one example of dissipative zones of eccentrically braced frames (EBFs).
Numerical Modelling of Single‐span Portal Frames
Authors: Ahmed Aya , Hu Tong , Walport Fiona , Gardner Leroy 
Published: September 2022

AbstractPortal frames are a common form of structural system used to create efficient wide‐span enclosures. Over the past few decades, the design of portal frames has evolved in the direction of longer, lighter and taller structures, while cladding systems have become more substantial. Although this allows larger spaces, it can also result in heightened structural challenges, such as increased frame flexibility, a greater portion of the load being borne by the cladding and greater differential thermal movement. This has led to general concerns related to the effects of scale. To investigate these concerns, with a particular focus on the contribution of the cladding to the global strength and stiffness of the structure (also referred to as the stressed skin effect), and the resulting demands placed on secondary components, this study presents the development of a numerical model for the accurate representation of the structural response of full single‐span portal frames. The model is validated herein in two ways; (i) through validation of each individual frame component against relevant physical experiments, and (ii) through validation of the full model against full scale frame tests. Finally, a preliminary parametric investigation is presented.
The Beneficial Influence of the Roller‐straightening Process on the Bearing Capacity of Steel Columns
Authors: Saufnay Loris , Tibolt Mike , Jaspart Jean‐Pierre , Demonceau Jean‐François 
Published: September 2022

AbstractThe roller‐straightening process is a steel cold production technique which consists of passing a steel element through a series of rolls that bend the member, what leads progressively to a reduction of the initial geometrical imperfections along its weak axis. In addition, this post‐treatment process induces a continuous yielding of the steel member and thus may present a second interest which is the reduction of the compression residual stresses at flange tips. This modification of the residual stress pattern could lead to an increase of the carrying capacity of steel columns.Indeed, the capacity of columns in compression is evaluated through the European buckling curves reported in EN1993‐1‐1 in which the compression resistances are highly affected by the initial bow imperfections and residual stresses resulting from the rolling process.However, whilst all long products seem to be systematically straightened nowadays, EN1993‐1‐1 does not consider the potential beneficial effect of the roller‐straightening process. In other words, it means that the current recommendations of EN1993‐1‐1 neglect the potential benefit of this process on the buckling capacity.In this context, a collaboration for a research study has been initiated between ArcelorMittal and the University of Liège to numerically estimate the residual stress patterns after the roller‐straightening process of three relevant heavy H‐shape profiles (HE 600 B, HE 500 M and HD 400 x 262) in HISTAR®460 and evaluate whether these new distributions could lead to a significant increase of the column bearing capacity.
Residual Stresses in Welded I‐section Members with Flame‐cut Flanges
Authors: Lebastard Maxime , Couchaux Maël , Bureau Alain , Hjiaj Mohammed 
Published: September 2022

AbstractThe residual stress distribution influences substantially the stability behavior of steel members. Its shape, directly impacted by the fabrication process, is very different in hot‐rolled and welded members. Among welded members, flame‐cut flanges and hot‐rolled flanges are commonly employed in practice. However, buckling curves of Eurocode 3 are based on experimental tests and numerical simulations performed on welded members having hot‐rolled flanges only and lead to conservative results comparatively to the previous French design standards but also to hot‐rolled members. Investigations are strongly needed to adapt the existing buckling curves to welded members using flame‐cut flanges and a first step is to estimate the residual stress distribution in such members.The results available in the literature dealing with residual stresses measurements in welded members with flame‐cut flanges investigate stocky profiles that can be far from common practice, welded members being preferably slender sections. This paper presents the results of an experimental campaign on residual stresses performed on eight slender welded members varying the flange width and thickness as well as the flange type : hot‐rolled or flame‐cut. The measurements were performed using the sectioning method. A new model for residual stress distribution in welded I‐section members with flame‐cut flanges is then proposed based on these tests results and existing data from the literature.
Resistance of Closely Spaced Back‐to‐back Connected Equal Leg Angle Sections
Authors: Beyer André , Delacourt Guillaume , Bureau Alain 
Published: September 2022

AbstractIn the framework of the European RFCS project ANGELHY, the resistance of built‐up members fabricated from angle sections is studied, amongst others. This paper focusses on the resistance of back‐to‐back connected angle sections. The studied built‐up members are connected through bolted packing plates. Due to the flexibility of this connection, the back‐to‐back connected members do not fully act as a single homogeneous member but the connection stiffness has to be accounted for. However, Eurocode 3 does not provide a clear and generally accepted method for the determination of the buckling resistance of back‐to‐back connected members that do not respect a limit distance of 15imin between the packing plates. This limit is very low and therefore there exists a need of a design method overcoming the limitations. Throughout this paper, a design method will be derived based on a comprehensive numerical study. The numerical model is based on solid finite elements and has been validated with physical tests. Owing to the use of solid elements, it is possible to model explicitly the bolts, the packing plates and all contact regions.
Classified generalized linear mixed model prediction incorporating pseudo‐prior information
Authors: Ma Haiqiang , Jiang Jiming 
Published: September 2022

AbstractWe develop a method of classified mixed model prediction based on generalized linear mixed models that incorporate pseudo‐prior information to improve prediction accuracy. We establish consistency of the proposed method both in terms of prediction of the true mixed effect of interest and in terms of correctly identifying the potential class corresponding to the new observations if such a class matching one of the training data classes exists. Empirical results, including simulation studies and real‐data validation, fully support the theoretical findings.