bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determining the Yield Surface of a Metal Using Notched Strip Specimens: Geometry Optimization
Authors: Morales Mariela Mendez , Becque Jurgen 
Published: September 2021

AbstractDetermining the full yield surface of a metal by experimental means is a rather complex task, due to the need to subject the material to a multi‐axial stress state that includes shear. However, an interesting concept (originally credited to Hill and Bijlaard) has been proposed, whereby metal strips with oblique notches are loaded in uniaxial tension. This specific shape forces a narrow yield neck to develop between the roots of the notches, subject to multiaxial straining. The presented research aimed to further develop and optimize this concept. It was previously suspected that the geometry of the test specimens has a potentially significant effect on the results of the experiment. By means of the finite element method, a parametric study was completed to evaluate which geometric variables have the largest influence on the results and to determine the range within which these parameters yield reliable results. It was discovered that certain variables, such as the width of the neck and the radius of the notch root, had a significant impact on the results, whereas others, such as the neck angle or the opening angle of the notch, had very little or even no influence at all. Based on these results, a specific geometry was proposed for the test specimens, as a first step towards a standardized test procedure.
Lateral Cyclic Performance of Hybrid Fabricated Beam‐Columns
Authors: Javidan Fatemeh 
Published: September 2021

AbstractIn this paper, a high‐capacity fabricated hollow section is proposed as a lightweight replacement for concrete‐filled composite members which are commonly used as beam‐columns in seismic zones. The lateral cyclic performance of the fabricated hollow beam‐column comprising of mild steel plates (grade 250) and high strength steel (HSS) tubes (grade 750) is investigated. A finite element model is developed and validated against available experimental data. To incorporate the cyclic hardening and softening of both steel materials, a combined plasticity model obtained from low‐cycle material tests is incorporated in the finite element model. A comprehensive sensitivity analysis is undertaken to propose an optimum slenderness design for the thin‐walled steel elements with ductile failure. While the high strength steel tube elements can significantly increase the axial and lateral capacity of the hybrid section, the cyclic failure mechanism is governed by mild steel plate elements, rather than a sudden failure in the high strength steel tubes.
Pseudo‐dynamic testing of a full‐scale two‐storey steel building with FREEDAM connections
Authors: Di Benedetto Sabatino , Francavilla Antonella Bianca , Latour Massimo , Piluso Vincenzo , Rizzano Gianvittorio 
Published: September 2021

AbstractThe recent earthquakes have underlined the need for more advanced design philosophies able to avoid or reduce direct and indirect costs deriving from the occurrence of destructive seismic events. In fact, the traditional seismic design approach is based on performance levels implying the onset of damage which can be, in many cases, difficult to repair. In order to address social expectations and the need for resilient buildings, recently, novel low‐damage design philosophies have been proposed. These are based on the introduction, in particular points of the structure, of friction dampers able to dissipate large amounts of energy and to protect the structural members from damage. This is the case, for instance, of the Sliding Hinge Joints (SHJs), developed by the research group of the University of Auckland in 2005, or of the FREE from DAMage joints (FREEDAM), developed starting from 2009 at the University of Salerno.Many experimental and analytical research efforts have been devoted to understanding the response of such connections. Nevertheless, currently there is still a lack of knowledge dealing with their seismic response in full‐scale buildings. In order to provide a contribution to fill this knowledge gap, an experimental program is currently ongoing at the STREngTH (STRuctural Engineering Testing Hall) Laboratory of the University of Salerno dealing with the pseudo‐dynamic testing of a full‐scale two‐storey steel building equipped with FREEDAM joints. The mock‐up has been subjected to a sequence of five accelerograms and the results have confirmed that FREEDAM connections provide large energy dissipation capacity and plastic rotation supply, thanks to their regular and plumb hysteretic loops. The experimental results have been complemented with numerical models developed with the software OpenSees.
Numerical Study on An Innovative Elastomeric‐Steel Cushion Damper
Authors: Moeini Milad Ehteshami , Razavi S. Ali , Yekrangnia Mohammad , Khaloo Alireza 
Published: September 2021

AbstractIn this research cyclic performance of a newly developed energy dissipating device is investigated through finite element studies. The device is constructed using yielding steel Cushions and bonded rubber cubes. The Cushions dissipate the induced energy of earthquakes while the rubber cubes provide lateral constraint and post‐elastic stiffness for the bracing system due to the Hyperelastic behavior of the rubber material. The main advantage of the proposed damper is its little maintenance expense and cost efficiency since the steel Cushions can easily be replaced. In this paper, the requisite details are presented for the application of the proposed device. It can be observed from the analytical results that the proposed damper exhibits full and wide hysteresis loops resulting in excellent equivalent viscous damping while maintaining adequate lateral stiffness at various displacement levels. The dissipated energy per cycle and the respective effective stiffness and equivalent damping of the model are presented in this study.
Design Recommendations of Steel Compressed Columns of Variable Cross Sections
Authors: Marcinowski Jakub , Kołodziej Sebastian , Błażejewski Paweł 
Published: September 2021

AbstractSteel columns of hollow cross‐sections being the body of revolution and simply supported at their ends are considered in the paper. Columns of such shapes are recently very frequently proposed by architects of public facilities such as airports, entertainment halls and other objects encountered in engineering practice. The provisions of the EN 1993 standard do not provide for direct procedures that can be used when designing such columns. In this paper authors present the comparatively simple procedure which can be used by designers of steel columns of such shapes. The value of critical force required in the procedure was derived for columns of variable cross section by means of Mathematica™ system. The closed formulae were obtained for a rod with a certain, predefined geometry being the surface of revolution. To this end the Rayleigh quotient in the first form resulting from the energy criterion of stability was used and the half‐wave sine function was adopted to describe the buckling form. Critical forces obtained by means of derived formulae were compared with numerical solutions. To assess the compression resistance of considered rods the general Ayrton‐Perry approach was applied and bow imperfection with assumed amplitude was used in the analysis. Amplitudes of these initial imperfections can be chosen in correspondence to fabrication quality assumed in advance. An example inserted in the paper confirms the effectiveness of the proposed procedure. Formulas for allowable compressive force derived by the authors and presented in the paper can be treated as a measure of compressive resistance and used by engineers designing columns of the considered shape.
Performance‐based assessment of seismic‐resilient steel moment resisting frames equipped with innovative column base connections
Authors: Lettieri Annarosa , Elettore Elena , Freddi Fabio , Latour Massimo , Rizzano Gianvittorio 
Published: September 2021

AbstractLow‐damage and self‐centring column base connections have been proposed in the last two decades as innovative solutions able to provide the seismic resilience in Moment Resisting Frames (MRFs). Although many works have demonstrated the benefits deriving from the adoption of these systems, only a few research studies investigated the significant parameters influencing their self‐centring capability. This paper investigates the influence of the frame layout (i.e., storeys and bays number) on the seismic performance of perimeter MRFs equipped with damage‐free self‐centring column bases previously studied by the authors. Nine case‐study perimeter steel MRFs are designed and modelled in OpenSees. Incremental Dynamic Analyses are performed monitoring both global and storey‐level Engineering Demand Parameters, including peak and residual interstorey drifts. Fragility curves are subsequently used to evaluate the self‐centring capability of the structures. The present study provides insights on the use of the adopted connections for the residual drift reduction of MRFs and defines the boundaries of the investigated parameters for their application. Results highlight that the self‐centring behaviour is particularly sensitive to the number of storeys and tends to reduce with the increasing height of MRFs equipped with the proposed connections.
Trigonometric series solutions for the geometric nonlinear analysis of the compressed thin plate
Authors: Nedelcu Mihai 
Published: September 2021

AbstractThe Eurocode uses the Effective Width Method for the Cold Formed Steel design and this method is currently based on the semi‐empirical Winter formula. This formula is based on the von Karman's approach which considers that the ultimate load on a compressed thin plate with large deflections is reached when the critical stress of the plate effective width is equal with the yield stress. Winter modified the formula in order to match the experimental results but there are numerous cases in which the formula underestimates the strength capacity. Also, the formula has no input for the initial geometric imperfections. This paper presents a semi‐analytical alternative based on the trigonometric series representation of the displacement field. The procedure is applied to the uniform compressed rectangular plate with simply supported edges (internal plate of a thin‐walled member) and with one free longitudinal edge (outstand plate). This new approach considers the initial geometric imperfections with various shapes.
Printing imperfections – geometric patterns to improve resistances of 3D printed steel plates
Authors: Wang Jie , Evernden Mark , Chater Ben , Pan Jingbang 
Published: September 2021

AbstractTraditional structural steel manufacturing routes typically produce prismatic members comprising of flat plate elements. Under compressive actions, the capacity of these sections is often dominated by plate instability of the lowest buckling mode. The current study proposes the use of innovative additive manufacturing to produce metallic plate elements with predefined imperfection patterns capable of postponing instability via the lowest buckling mode thus providing increased buckling resistances. To this end, a program of numerical modelling has been carried out to explore various combinations of predefined surface waves with different amplitudes in stainless steel square hollow section stub columns of varying slenderness. Their stiffness, strength, and material consumption against the typical flat sided structural steel members with the same nominal dimensions were assessed. The study identifies the possibility for ‘imperfect’ sections to achieve up to a 50% increase in strength for a minimal increase in material consumption. This innovative study highlights the significant potential of new metallic additive manufacturing technologies in achieving unprecedented material efficiency and economic design in the future steel construction industry.
Cyclic Performance of Cold‐formed Steel Moment Resisting Frames
Authors: McCrum Daniel P. , Wrzesien Andrzej M. , Simon Jordan , Grimes Michael , Broderick Brian , Lim James B.P. 
Published: September 2021

AbstractThis paper investigates the seismic performance of a single storey moment resisting cold‐formed steel (CFS) portal frame through cyclic testing. Six monotonic and six cyclic tests were performed on three different section sizes of CFS portal frames. The portal frames were 3.2m long x 2.2m high and the CFS sections bolted with either perfect‐fit tolerance bolt holes (PTBH) or normal tolerance bolt holes (NTBH) connections. Connections with NTBH are standard in CFS, but connections with PTBH are often only used for short‐spanning frames. Results from the tests demonstrated that both PTBH and NTBH connections had stable hysteresis and good hysteretic energy dissipation capacity and ductility. On average, the NTBH connections performed better under cyclic loading in comparison to the PTBH connections (5.4% larger ductility and 22.3% increased energy dissipation). Strain gauge results show failure due to combined bending and bi‐moment stresses, of which the bi‐moment stress component accounted for 41% of the total longitudinal stresses at the section web. It should be noted that bi‐moment stresses are often incorrectly ignored by practitioners; the experimental test results thus show that by doing so the sections would fail at 59% of the design moment.
Rapid Seismic Economic Loss Assessment for Steel Concentrically Braced Frames Designed to Eurocode 8
Authors: Hickey John , Broderick Brian 
Published: September 2021

AbstractThis paper presents a rapid method for calculating the expected earthquake repair costs incurred by steel concentrically braced frame structures designed to Eurocode 8. The method adopts the FEMA P‐58 performance assessment methodology which is based on the predicting Engineering Demand Parameters (EDPs), such as peak inter‐story drift and peak floor acceleration, at various seismic hazard intensity levels of interest and then using these EDPs to calculate expected damage and associated economic losses. Typically, multiple nonlinear time history analyses (NLTHA) are employed to calculate the required EDPs, however this can be computationally expensive and technically challenging. This paper proposes the use of regression equations, developed from a large number of nonlinear analyses, as an alternative to NLTHA for EDP prediction. This allows loss assessment to be carried out without the need for multiple NLTHA, a process termed rapid loss assessment. The proposed equations are applied in loss assessment for three case study CBFs. It is shown that the economic losses predicted by the rapid method compare well with results obtained from conventional NLTHA‐based assessment.
Seismic design of innovative steel frames with partially‐prefabricated infill walls
Authors: Piattoni Quintilio , Freddi Fabio , Zona Alessandro , Leoni Graziano , Dall'Asta Andrea , Argentoni Alessio 
Published: September 2021

AbstractHybrid steel and concrete seismic‐resistant systems made by steel frames with reinforced concrete infill walls (SRCWs) have potential advantages over structural solutions made only by steel or reinforced concrete (RC). In fact, the high initial stiffness of concrete is useful to minimize the damage of non‐structural elements under frequent (low to moderate) earthquakes while the ductility and dissipative capacity of the steel allow good performances under rare (high‐intensity) events. Eurocode 8 considers SRCW systems to behave essentially as RC walls. However, numerical analyses on SRCWs, designed according to the Eurocodes, pointed out an unsatisfactory seismic behaviour with discrepancies between the behaviour assumed in the design and the simulated response under seismic actions. Indeed, the idea of stiffening a steel frame with a RC infill leads complex mechanisms that are difficult to control as being affected by many variables. In this study, some of the recent developments made for innovative SRCW are transferred to hybrid steel and concrete walls with partially‐prefabricated infills. Numerical models are analysed to understand the global behaviour of the considered SRCWs and to provide a preliminary validation of the proposed structural solution.
Residual Drift Estimation for Moment Resisting Frames with Steel Degradation Properties
Authors: Petreski Borjan , Gjorgjiev Igor 
Published: September 2021

AbstractInter‐story drifts are the most important engineering demand parameters required for the evaluation of performance of structures subjected to lateral loading. Even though the transient inter‐story drifts are usually used for the assessment and design using the codes of practice, the residual drifts often govern the economic loss in buildings. Therefore, the residual drifts can be critical in the post‐earthquake evaluation of the structures and should be given greater consideration in the process of design of steel moment resisting frames (MRFs). This study examines an improved approach for the estimation of the residual drift demands in steel moment resisting frames subjected to realistic earthquake loading. The advancement is implemented through application of a steel degradation material model in order to capture the stiffness degradation in the inelastic range correctly. Then, this modelling is compared with simplified bilinear steel material model in order to demonstrate the advantages of the deterioration model in performance‐based assessment.
Seismic performance of MR steel frames via Incremental Dynamic Analysis
Authors: Bernuzzi Claudio , Rodigari Davide , Simoncelli Marco 
Published: September 2021

AbstractThe Incremental Dynamic Analysis (IDA) represents a promising design approach to assess the performance and post‐earthquake load carrying capacity of steel frames. Generally, only the maximum transient inter‐story drift is considered as damage intensity measure (DM), when IDA is carried out. In the Authors' opinion, to better appraise all the aspects characterizing the damage state of the structures, additional DMs should be considered, like residual inter‐story drift, residual load carrying capacity and low‐cycle fatigue (LCF) damage, whose quantitative evaluation is currently neglected in seismic design provisions.The presented paper deals with Moment‐Resisting (MR) steel frames for which the structural performance is evaluated via IDA. In particular, four multi‐story frames differing for the beam‐to‐columns connections have been considered. The aforementioned DMs have been evaluated at the specific seismic intensity correspondent to the design performance level of Immediate Occupancy, Life Safety and Pre‐Collapse. Research outcomes underline how the additional information obtained from the proposed DMs provide a more accurate prediction of the damage state of MR frames, with respect to the one assessed only with the maximum transient inter‐story drift, especially when damage and residual load carrying capacity have to be quantify.
Novel adaptive steel hysteretic damper for an enhanced seismic structural performance
Authors: Gandelli Emanuele , Weber Felix , Chernyshov Sergey , Distl Johann , Taras Andreas 
Published: September 2021

AbstractTraditional Hysteretic Dampers (HDs) are installed in buildings to enhance their seismic performance by increasing the effective stiffness and damping and are usually designed to guarantee the structural safety for severe Ultimate Limit State (ULS) seismic events. As a negative consequence, only minimal damping is provided during weak but more frequent Serviceability Limit State (SLS) earthquakes since HDs mainly operate in their elastic regime. This can cause high Peak Floor Accelerations (PFAs) that are detrimental for sensitive non‐structural components (NSCs), like electric network, elevators, and computers, whose integrity is crucial in high‐technological buildings (e.g. hospitals, and emergency centers). In order to improve this unacceptable situation, a novel Adaptive Hysteretic Damper (AHD) was developed by the authors. The AHD can modulate its effective damping and stiffness to its actual deformation (i.e. PGA level) leading to: (i) reduced PFAs and enhanced building response to minor SLS earthquakes; (ii) not impaired structural safety under severe ULS events. The AHD force‐displacement characteristics are experimentally assessed and nonlinear time‐history analyses are carried out on a case‐study structure to demonstrate the enhanced seismic performances compared to common HDs.
Influence of the ballasted track on the dynamic behaviour of steel railway bridges
Authors: Stollwitzer Andreas , Fink Josef , Malik Tahira 
Published: September 2021

AbstractThe calculated dynamic behaviour of railway bridges during high‐speed traffic differs from the actual behaviour of its bearing structure. In the case of steel railway bridges, dynamic calculations often overestimate the actual vibration responses and therefore lead to uneconomical results. This gap between calculation and measurement constitutes a complex research issue, whereas the consideration of the ballasted track in dynamic calculations has a major influence. Concerning the damping and stiffness properties of the ballasted track there is a wide range of various mechanical models. However, there is no generally applicable track‐structure model for dynamic calculations which reflects reality in a satisfactory way. In their effort to close the gap between calculation and measurement and to develop accurate track‐structure models for dynamic calculations that take into account the dynamic properties of the ballasted track, researchers at TU Wien have developed a large‐scale test facility which allows for specific research of the dynamic behaviour of the ballasted track. This paper describes the operating principle of the test facility and provides insight into the dynamic effects observed in it, in particular with regard to its vibrations and damping behaviour.
Experimental Study on Steel Slit and Shear Panel for Seismic Resistance
Authors: Gashi Ferit , Bontempi Franco , Petrini Francesco 
Published: September 2021

AbstractThis paper summarizes the experimental campaign carried out for the development of new steel energy dissipative devices named Slit Dampers (SDs) designed for earthquake protection of structures. A total of eighty‐two steel shear plates with different openings and thicknesses are tested to investigate their behaviour under cyclic pseudo‐static loading. Eight types of steel shear plates are studied, including the SD with narrow slits that divide the plate into rectangular links, and the butterfly fuse with a diamond‐shaped opening that creates butterfly shape links in the plate. Other varying test parameters are loading rate, material strength, and the number of in‐parallel damper elements. It is expected that the proposed model can be successfully used to predict the behaviour of dampers in real‐world applications.
Structural member stability behaviour of steel channels
Authors: Bours Anna‐Lena , Winkler Rebekka , Knobloch Markus 
Published: September 2021

AbstractIn structural engineering, steel channels are often used for girders of facade constructions of steel halls, platforms, gangways and stair stringers. Since the loads are often applied to the flanges of the mono‐symmetric cross‐sections the channels are most commonly subjected to scheduled torsion. So far, a simplified design method for steel channels in bending, compression and torsion is missing.Based on an experimental study, this paper analyses the structural behaviour of steel channel members in bending, compression and torsion. An integrated experimental and numerical study analyses the structural member stability behaviour. The study includes the analysis of the load‐rotation behaviour, of the development of internal forces and moments during load increase as well as of the residual elastic cross‐sections as a result of the development and spreading of plastic zones. Finally, the paper compares the ultimate loads of three verification methods, that are adopted and extended for steel channels, with experimental results.