bluuebunny/crossref_metadata_2025 huggingface dataset:
Stainless Steel SHS and RHS Beam‐column Design Proposal
Authors: Zidlicky Bretislav , Jandera Michal
Published: September 2021

Presented research investigates behaviour of stainless steel square hollow section (SHS) and rectangular hollow section (RHS) members loaded by compressive force and uniaxial bending moment combination. Experimental program of 20 eccentrically loaded pin‐ended compressed austenitic stainless steel member tests was carried out. Numerical model using geometrically and materially non‐linear analysis with imperfections (GMNIA) was created in finite element software Abaqus. Validation of the numerical model was made based on the data obtained from the experimental program. The validated model was used for a comprehensive numerical parametric study which covered austenitic, ferritic and duplex stainless steel types. Furthermore, member slenderness, cross‐section slenderness and ratio between compressive force and flexural buckling resistance were set as variables as well. Bending moment was considered uniform along the member length. Data obtained from the numerical parametric study were used for the comparison with the existing stainless steel SHS and RHS beam‐column design procedures. Furthermore, new interaction formulae were proposed and evaluated by a reliability analysis.
An experimental assessment of hot‐rolled carbon and stainless steel equal legs angles under compression
Authors: da S. Sirqueira Alan , da S. Vellasco Pedro C. G. , de Lima Luciano R. O. , da Silva André T. , Rodrigues Monique C.
Published: September 2021

Although stainless steel mechanical properties are similar to their carbon steel counterparts, the nonlinear stainless steel characteristics naturally leads to diverse design recommendations. These peculiar features directly modifies the behaviour of the ultimate limit states related to instability. The Eurocode 3: Part 1‐4 (2006) stainless steel design standard can be utilised for hot‐rolled, welded and cold‐formed cross‐sections, but this standard prescriptions are very conservative due to the lack of tests. An instability limit state that presses for additional research is associated to hot‐rolled stainless steel angles. This paper is centred in experiments made on hot‐rolled carbon and stainless columns steel equal legs angles under compression. These experiments were carried out on 500 mm to 1000 mm columns lengths with failures involving flexural‐torsional buckling.
Static Behaviour of High‐Strength Steel CHS T‐Joints under In‐Plane Moment Loading
Authors: Kim Seon‐Hu , Lee Cheol‐Ho
Published: September 2021

In steel moment frames or vierendeel trusses comprised of hollow section members, T‐shaped joints are formed that are subjected to brace in‐plane bending moment (IPB). For mild steel, a large number of studies have been conducted on the behavior of tubular T‐joints subjected to IPB. However, the studies for high‐strength steel T‐joints are quite limited and mostly focused on axially loaded cases. In this paper, recent testing program conducted by the authors for high‐strength steel circular hollow section (CHS) T‐joints under IPB was presented. Supplemental numerical parametric study was conducted using the test‐validated nonlinear finite element (FE) analyses. In the FE analyses, various geometric shapes were considered such that the effect of key geometric factors and important failure modes could be identified. Based on the experimental and numerical results, a more rational deformation limit criterion under IPB loading was first proposed which can be applied to both mild and high‐strength steel joints. The chord plastification strength of high‐strength steel joints was evaluated using existing formulae and the required material factor for 700 MPa steel was suggested.
Stability Design of High Strength Steel Beams
Authors: Tankova Trayana , da Silva Luís Simões , Rodrigues Filipe
Published: September 2021

EN 1993‐1‐1 gives stability design rules for columns, beams and beam‐columns up to S460, whereas EN 1993‐1‐12 gives additional guidance for S500 up to S700. Recent studies on flexural buckling of welded H, I and box columns in steel grades S460 to S960, even though limited, show that improved curves can be used for members in high strength steel (HSS). This enhanced behavior is usually attributed to the improved material properties but mainly due to the more favorable residual stress distribution. Furthermore, the behavior of unrestrained beams in HSS has not been studied. At present in EN 1993‐1‐1, the design rules for lateral torsional buckling of beams are not dependent on the steel grade, meaning that the code does not distinguish between beams in conventional strength steel or HSS. In pursuit of answer to the mentioned shortcomings, within the European Project STROBE evaluation of the European stability design rules is carried out. The research is based on experimental programme covering 14 full‐scale tests, residual stress measurements, advanced numerical models and analytical derivations. This paper provides a summary of the experimental programme, the results for lateral‐torsional buckling of beams are discussed and further compared with the current code recommendations.
Post‐Fire Mechanical Properties of Steel S900MC
Authors: Abebe Zemenu , Shakil Saani , Lu Wei , Puttonen Jari
Published: September 2021

This paper discusses mechanical properties after one heating and cooling cycle using experimental tests. The material tested was steel S900MC, which has the nominal yield strength of 900 N/mm2. The specimens were tested with being first heated up inside a furnace to a pre‐defined temperature, then cooled down to the room temperature. I n order to study the effects of cooling rates on mechanical properties, two different cooling methods were used: cooling inside furnace, and cooling in the air.

The results indicated a clearly reduction of the strength when the steel was cooled from the temperature above 500 °C. The steel reduced 40% of its yield strength after cooled from 700°C, while only 20% remained when cooled from 900°C. The elastic modulus was regained to its original value after the steel was cooled from temperatures below 500°C, whereas about 80% was regained when the steel was cooled from 900°C. Cooling temperatures between 700°C and 900°C produced a large scatter among all the mechanical properties. The cooling rate did not affect the mechanical properteis when the maximum temperature remains below 700 °C before the cooling starts. However, when exposed to an elevated temperature above 700°C the effect is visible. The air‐cooled specimens had higher strength and lower ductility than furnace cooled specimens. The results of this study will help to evaluate the load‐bearing capacity and reusability of the steel members after fire‐exposure.
Evaluation of material properties of 3D printed carbon steel for material modelling
Authors: Tarus Iulia , Xin Haohui , Veljkovic Milan , Persem Nicolas , Lorich Laurent
Published: September 2021

A procedure and material properties of tensile coupon specimens are presented. The coupon specimens were cut from the plates printed by ArcelorMittal Global R&D Bars & Wires. For this, a welding robot based on Wire Arc Additive Manufacturing (WAAM) procedure and welding wire AWS 5.18 ER70S‐6 Böhler K56 were used. The specimens were cut in different directions to the printing direction, to investigate possible material anisotropy. Surface milled and as printed specimens were investigated focusing on the influence of surface irregularities on the material behaviour. 2D Digital Image Correlation (DIC) was used for evaluating engineering stress‐strain diagrams, E‐modules and Poisson ratios for each specimen.

Obtained results clearly indicate that 3D printing technology was appropriate, showing material properties rather close to the rolled mild steel and minor anisotropy, E=200GPa, fracture strain above 25%, strength/yield stress beyond 1,3, for fy=420 MPa. Roughness of the surface was just 0,2mm for the thickness of 3,7mm, obtained using the wire diameter of 3mm.

Finite Element Method (FEM) was used to validate the experimental results and to calibrate damage material properties. Results of uniaxial coupon specimens, the stress‐strain curve, is divided in 3 stages: the elastic stage, the plastic stage and the coupled plastic stage. The coupled plastic‐damage stage is further decomposed into the plastic‐dominated zone and the damage‐dominated zone. The true stress‐strain curve after necking is calibrated by FEM.
Comparative Assessment of the Seismic Behavior of Reduced‐Core Length and Conventional Buckling‐Restrained Bracing Systems
Authors: Moeini Milad Ehteshami , Razavi S. Ali , Imanpour Ali
Published: September 2021

The buckling‐restrained braced frame (BRBF) is an appropriate lateral system for resisting seismic excitations. This system has high lateral stiffness and stable hysteretic loops mainly due to restraining global buckling of the brace core under compression. Even though BRB is an improved version of the conventional brace, it is not yet an ideal system since there are deficiencies regarding the performance of this system. Notable decrease of lateral stiffness after yielding of the BRB cores and significant residual drifts are instances of the deficiencies in BRBFs, which have been recognized as problematic and costly in recent earthquakes.

Reducing the core length of the BRB can effectively increase the lateral stiffness as well as decreasing the drifts and residual drifts of the structure without any increase in the cross‐sectional area of the core. In this research nonlinear static pushover analyses have been conducted on 4 buildings including 4 and 9 story structures with conventional and reduced core length BRBs with diagonal and inverted chevron brace configuration. Both pinned and rigid end‐connections were considered for the beams in the braced bays. A 4‐story dual SMRF‐BRBF was included for better assessment of the contribution of frame action to the structural behavior. The results indicate that the reduced length BRBs have much better seismic behavior. Furthermore, they are replaceable, repairable and more cost‐efficient compared to conventional BRBs.
On the resistance of arbitrarily ring‐stiffened welded bins subject to axial compression
Authors: Jäger‐Cañás Andreas , Li Zheng , Pasternak Hartmut , Taras Andreas
Published: September 2021

Ring‐stiffened flat bottom tanks are widely used in many industries for the storage of liquids, such as oil, fertilizers, water, sewage and sludge. Material efficiency is achieved by combining thin plates with ring‐stiffeners. When the bin is covered by a dome or cone roof, high meridional forces due to live or snow loads may trigger axial buckling of the shell. Ring stiffeners are beneficial, not just against buckling due to wind, but to reduce the risk of stability failure of tanks and silos caused by meridional compression as well.

This paper presents the outcome of a parametrical study concerned with axial buckling and the most effective placement of the stiffening rings depending on the stiffener distance, cross‐sectional area and slenderness of the cylinder. Buckling curve parameters are deduced using the modified capacity curve. These allow the direct application of the analysis results in a hand calculation procedure that enables practitioners to take into account the benefits, which come with ring stiffeners against buckling due to axial compression.
Experimental Investigation of Steel Frames Equipped with Easily Replaceable Components
Authors: Andreotti Roberto , Giuliani Giulia , Tondini Nicola , Bursi Oreste S.
Published: September 2021

Modern techniques of structural design are effective in preventing structural collapse due to earthquake actions. Nevertheless, repairability has become an important issue to deal with in order to minimise the economic and environmental impact of structural damage. In this respect, this paper presents the design of experimental tests on full‐scale specimens of steel frames to be tested according to hybrid simulation. This work is conducted within the ongoing European research project DISSIPABLE that seeks to test easy to replace structural components installed in steel buildings. In fact, by including these Dissipative Replaceable Devices (DRD) into the building, it is possible to provide full post‐earthquake functionality after damage. Three are the devices that will be tested, namely DRD1, DRD2 and DRD3, which are going to be briefly presented in the paper. Five hybrid tests will be performed and major details will be given to the numerical modelling of the components and the identification of the substructures to be employed in the tests. Finally, the design of the physical substructure and the test setup will be briefly described.
The effect of rotational component of earthquake excitation on the response of steel structures
Authors: Pnevmatikos Nikos , Konstandakopoulou Foteini , Papavasileiou Georgios , Papagiannopoulos George , Broukos Pantelis
Published: September 2021

This work is on the influence of the rotational component of earthquake excitations to the response of steel structures. In most studies, seismic input is being modeled only using the translational component of the ground acceleration, while the rotational one is ignored. This was due to the observation that the rotational component had minimal effect on low‐rise buildings. Hence, the accelerometers used would not measure it, leading to a lack of records. Nowadays, technology provides such instruments and relative records are made available. Indicative of that is that elastic design response spectra for rotational components are introduced to the design codes. In this paper, the results on structural response and internal forces due to the rotational component of a seismic excitation on the steel structures are examined. Dynamic time history analysis and response spectrum analysis of different steel structures are performed (a) considering the rotational component of the excitation and (b) without it. From the numerical results it is shown that the impact of rotational component in structural response and internal forces of the steel structures is significant and should not be ignored during structural design.
Incremental Dynamic Analysis of Concentric X‐Braced Frames Designed to the TBEC 2018
Authors: Kor Efecan , Ozcelik Yigit
Published: September 2021

Concentrically braced frames (CBF) are an efficient lateral force resisting system which provides significant lateral stiffness and lateral strength. One of the commonly used configurations of CBFs are cross braced (X‐braced) frames where braces are placed diagonally between the beam‐column joints of adjacent stories. The current Turkish seismic code, Turkish Building Earthquake Code 2018 (TBEC), was published in 2018 and superseded the former code, Turkish Earthquake Code 2007 (TEC) as of January 2019 with several differences such as introduction of yield mechanisms for CBFs, seismic hazard levels, and calculation of earthquake loads. Due to these differences, CBFs designed to TBEC are expected to yield different member sizes compared to TEC. Although the seismic behaviour of CBFs designed to TEC is well‐understood, that of CBFs designed to TBEC is still unknown and there has been no study on this topic. This study aims to assess the seismic performance of X‐braced frames designed to TBEC. To this end, a two‐story X‐braced frame was considered, and the seismic collapse performance of this frame was evaluated by adopting incremental dynamic analysis (IDA) under a set of twelve ground motions. The results of this preliminary study have provided insight into the collapse performance of CBFs designed to TBEC.
The Elastic Buckling Coefficient of a Rectangular Longitudinally Profiled (LP) Steel Plate with All Edges Simply‐supported
Authors: Xu Dongdong , Wang Yuanqing , Ban Huiyong , Liu Xiaoling , Liu Ming
Published: September 2021

The longitudinally profiled (LP) steel plate is a steel plate that having a special longitudinal shape which is continuously changed in the rolling direction by a special rolling process. It has many advantages, such as reducing the weight of structure, decreasing the number of the weld seem and improving seismic performance, which has widely application in ships, bridges and other areas. It will have broad application in the field of bridges construction in China. However, the local stability of the LP plate is less investigated in recently years. In this paper, the energy method was used to study about elastic buckling coefficient of a rectangular LP steel plate with all edges simply supported. Based on the Galerkin and Rayleigh‐Ritz method (GRM), the elastic buckling coefficient was obtained by transforming into a method that to solve the eigenvalues of the feature matrix. the result was verified by FEA method. And the curves of the elastic buckling coefficient with the relevant parameters such as aspect ratio and thickness change rate will be giving.
Equivalent bow imperfections for design by second order inelastic analysis
Authors: Walport Fiona , Gardner Leroy , Nethercot David
Published: September 2021

The stability of compression members is typically assessed through buckling curves, which include the influence of initial geometric imperfections and residual stresses. Alternatively, the capacity can be obtained more directly by carrying out a second order analysis using equivalent bow imperfections that account for both geometric imperfections and residual stresses. For design by second order elastic analysis, following EN 1993‐1‐1 recommendations, the magnitudes of the equivalent bow imperfections can either be back‐calculated for a given member to provide the same result as would be obtained from the member buckling curves or taken more simply as a fixed proportion of the member length. In both cases, a subsequent linear axial + bending cross‐section check is required. For design by second order inelastic analysis, there are currently no suitable recommendations for the magnitudes of equivalent bow imperfections and, as demonstrated herein, it is not generally appropriate to use equivalent bow imperfections developed on the basis of elastic analysis. Equivalent bow imperfections suitable for use in design by second order inelastic analysis are therefore established in the present paper and shown to yield reliable results when compared to benchmark results and current design guidance.
Development of a procedure for analysis and design of access scaffold
Authors: Mercier Charlotte , Khelil Abdelouahab , Mahmoud Firas Al , Blin‐Lacroix Jean‐Luc
Published: September 2021

The European design code for temporary work equipment and especially for scaffolding, NF EN 12811‐1, defines the cross‐section non‐linear plastic resistance criterion, which requires including initial imperfections in the global analysis of the structure. At the same time, the European design code for steel structures, Eurocode 3 Part 1‐1, establishes the buckling resistance criteria enabling to free ourselves from the modeling of initial imperfections. However, they do not offer the opportunity to exploit the non‐linear plastic resistance capacities of the cross‐section. Moreover, these buckling resistance criteria are often based on hypotheses and lead to inconsistencies between the verification with cross‐section criteria or with buckling criteria. The objective is to develop a procedure for analysis and design of access scaffold. The developed approach takes into account the interaction between section resistance and instability phenomena, and includes the influence of initial imperfections, such as initial defect of aplomb, lack of straightness and residual stresses. As far as possible, these effects will be decoupled. In order to verify the efficiency of the proposed procedure, several examples of typical scaffolding structures have been studied and the results prove the performance of proposed formulations.
Effects of warping torsion on the buckling behaviour of slender box sections
Authors: Derler Christoph , Unterweger Harald
Published: September 2021

Welded steel box sections are applied in various fields like in bridges as well as in structural engineering and industrial constructions. Apart from square‐shaped sections, these sections have the tendency to warp under torsion. Therefore – in case of torsional loading – restraints of the member's longitudinal displacements always result in additional stress components, the so‐called warping normal stresses and warping shear stresses. Due to the complex distributions of this warping stress components, frequently simplifications are done in practice within the design for ULS. It means, that only the St Venant shear stresses are considered, without taking into account the warping stresses. The neglect of these locally restricted warping stress fields seems accurate according to the ductile material behaviour of steel, as long as no part of the member is susceptible for local buckling. Within this paper a comprehensive study for slender box sections is presented, whether a buckling analysis with only the St Venant shear stresses, provides sufficient safety against buckling. The investigation included members under pure torsion as well as combined loading – consisting of axial force and torsion or bending and torsion. The ultimate load carrying capacity of the box section member was compared with the isolated buckling capacity of the individual plates with all‐round hinged supports, under only St. Venant shear stresses, while neglecting all additional occurring warping effects.
Bolted angle members in compression –new design model including joint stiffness
Authors: Unterweger Harald , Kettler Markus , Zauchner Paul
Published: September 2021

Previous research activities at Graz University of Technology, highlighted the fact that the joint stiffness has substantial influence on the compression member capacity of bolted angles.

Consequently, analytical models for the estimation of appropriate spring stiffness values have been developed for several practical applications in buildings and two‐bolt connections at both member's ends. The investigated connection details comprise a fixed gusset plate (e.g. as attachment to concrete walls), a joint to the flange of an I‐shaped girder and a joint to the web of an I‐shaped girder via a gusset plate. Based on that, a design model was developed for bolted angle members with rotational spring restraints at both member's ends and an eccentric compression loading N, in order to calculate the compression member capacity Nr.

This paper presents the design model in detail. In addition, the background of the model is shown, with a comprehensive calibration and validation procedure based on real tests and numerous numerical tests, respectively. Based on that, also complex failure modes, such as lateral torsional buckling, can be covered by the proposed model.
Stability Study of Cantilever‐Beams – Numerical Analysis and Analytical Calculation (LTB)
Authors: Kraus Matthias , Crişan Nicolae‐Andrei , Wittor Björn
Published: September 2021

According to Eurocode, the computation of bending strength for steel cantilever beams is a straightforward process. The approach is based on an Ayrton‐Perry formula adaptation of buckling curves for steel members in compression, which involves the computation of an elastic critical buckling load for considering the instability. NCCI documents offer a simplified formula to determine the critical bending moment for cantilevers beams with symmetric cross‐section. Besides the NCCI recommendations, other approaches, e.g. research literature or Finite‐Element‐Analysis, may be employed to determine critical buckling loads. However, in certain cases they render different results. Present paper summarizes and compares the abovementioned analytical and numerical approaches for determining critical loads and it exemplarily analyses corresponding cantilever beam capacities using numerical approaches based on plastic zones theory (GMNIA).
Analytical design method for the improvement of steel structures stability
Authors: Bové Oriol , Casafont Miquel , Ferrer Miquel , López‐Almansa Francesc , Roure Francesc
Published: September 2021

This article presents a design method for the improvement of steel structures stability by modifying their structural elements parameters. The available parameters can be selected from a predefined list of stiffness and ultimate capacities for joints and steel members. The proposed procedure is based on determining the critical load factor (ratio between the critical and the demanding loads: αcr = Pcr / PEd) and analyzing its sensitivity with respect to the design parameters, by using its gradient vector and Hessian matrix. The methodology is well suited for structures where the second order effects are relevant. A simple two parameter example is presented, and the general procedure for finite element analysis is outlined.
Study of Second‐order Effects of Steel Posts Supporting Rockfall Flexible Barriers
Authors: He Jian‐Wei , Zhao Lei , Liu Yao‐Peng , Chan Siu‐Lai
Published: September 2021

Flexible barrier systems have been widely used to resist falling rocks to protect railways, highways and residential buildings. As one of the important components of the system, steel posts are the supporting structures to maintain the system integrality and should not fail before the failure of other components. Under the impact of falling rocks, the ring net panels undergo large deflection causing high compression forces on the steel posts. To more accurately capture the structural behaviour of the steel posts, the nonlinear effects due to the initial imperfection of steel posts are considered. The performance of an individual steel post extracted from a full‐scale test is studied and the result reveals that the post would suffer global buckling about the minor axis with initial imperfection considered. Hence, the second‐order effects of steel posts should be incorporated in the global analysis of the flexible barrier system under rockfall impacts.
Buckling problems of patch loaded plates with and without stiffeners – analytical approach
Authors: Mijušković Olga , Žugić Ljiljana , Šćepanović Biljana , Ćorić Branislav
Published: September 2021

Generalized analytical approach, with exact stress solutions, to buckling problems of in‐plane loaded plate with and without stiffeners has been presented through the case of locally distributed direct stresses. Several mathematical models have been chosen to represent high webs of steel girders under the patch load. Initially, the basic model has been built to simulate a girder used in the experimental research where the external load is equilibrated by support reactions. The second, more complex model included shear stresses along vertical stiffeners with a task to equilibrate the external loads, simulating a single web segment between the stiffeners of a long girder. The upgrade of the second model by adding a longitudinal stiffener resulted in the third model. Considering the complexity of stress distributions within the plate under such a demanding load, an analytical model for these problems has not been presented earlier. For the first time the influence of flexural stiffeners' rigidity on the plate buckling has been analysed with the exact solutions for in‐plane stress distributions, for simply supported plate. Results confirm the high quality of the analytical solution for the first and the second model and speak in favour of this approach and its potential for further upgrading in the case of the third model.
Numerical investigations on built‐up cold‐formed steel beams for long spans
Authors: Ungureanu Viorel , Luka•ević Ivan , Both Ioan , Dubina Dan
Published: September 2021

The material saving obtained by using thin‐walled cold‐formed steel elements is well‐known for small structures as well as for common industrial structures. Additional to the truss type structures, another solution for obtaining light‐weight elements consist of connecting cold‐formed steel profiles as the flange to the corrugated steel sheets as the web. The resistance spot welding connecting technique is an advanced solution which offers reduced manpower and time for element production. These built‐up elements have shown their feasibility and high bearing capacity in previous studies. The present paper highlights additional characteristic responses of cold‐formed steel elements that extend in the response of built‐up corrugated web beams. The parameters considered in the numerical model include the span of the beam, the height of the beam, the thickness of the corrugated web plates, the thickness of the shear panel, the number of resistance spot welds and the orientation of the beam axis. By considering the real case configuration of industrial buildings, pitched roofs require the beams to have an inclination. The analyzed inclined beams exhibited increased capacity due to the redistribution of internal forces, growing the attractiveness of this solution.
On the use of systems for tests on stainless steel members and frames aimed at interoperability
Authors: Chacón Rolando , Puig‐Polo Càrol , Real Esther
Published: September 2021

An experimental development of systems for tests on stainless steel members and frames aimed at providing interoperability is presented. In the context of the project PINOX, tests on stainless steel members and frames have been conducted and provided with traditional measurement techniques. In addition, systems aimed at providing interoperable data to other platforms were added, namely: i) Measurement systems for developing low‐cost sensor‐to‐cloud applications as well as Digital Image Correlation, ii) Displacement measurement for developing virtual and augmented reality applications and iii) terrestrial laser scan (TLS) measurements for developing IFC models for design and analysis across BIM platforms. In the first case, the interest is related to developing interoperable, low‐cost, cloud‐based, open‐source tools in the context of structural engineering laboratories. In the second case, the interest is the use of virtual (VR) and augmented reality (AR) as alternative media when deploying tests on structural elements. The third case is explored for obtaining measurements and tracking initial imperfections on real structures, with great interest for in situ applications. Conclusions about educational, technological and practical potential of these applications are pointed out.
APK: a network to improve the interest in steel construction
Authors: Muzeau Jean‐Pierre , Silva Loïc Da
Published: September 2021

APK was launched in 1991. It is now 30 years old and it continues to produce and to disseminate pedagogical resources and to bring academics and professionals together. Every 4 years, seminars are proposed to examine how to adapt the different curricula to be as close as possible to professional requirements. Alternately, a workshop is organized to focus on a specific problem related to the advantages of steel in construction. Three times a year, a consistent journal which contains useful tools to improve lectures is circulated.

This paper describes how it has been possible for APK to maintain its activities and to remain as attractive as it was at the beginning. It emphasizes its main results, on the one hand for the academic world and, on the other hand, for the steel construction professionals. It clarifies the French system of education. It is a reminder of the European programs which have been disseminated. It describes some specific tools provided to the academics. It highlights proposals to attract students and make them interested in steel construction. It suggests different ways of promoting education to steel and provides some ideas to remain attractive in the future.
Reusability of existing structural steel
Authors: Coelho Ana M. Girão , Pimentel Ricardo , Sansom Michael
Published: September 2021

Using reclaimed structural steel on a project is an effective strategy to cut the environmental impacts associated with the production of new steel. This practice cannot be generalised to all structural steel however, as not all components can be effectively or safely reused. This paper focuses on single‐storey buildings, which are particularly attractive for reclaiming and reusing structural steel. Functional reusability requirements are set out below, in particular, the requirements related to the adequacy and reliability assessment of the reclaimed steel, to ensure that (i) the reclaimed material satisfies the performance requirements, which are essential for the mechanical, physical, dimensional, and/or other relevant properties of steel materials to ensure their adequacy to be used in structural design to EN 1993, (ii) the salvaged material meets the quality requirements from nominal specifications to ensure their reliability to be used in the structural design to EN 1993, and (iii) structures made from reclaimed steel have continued integrity.
Strain measurements on rails of crane runway girders to predict accurate wheel loads
Authors: Zauchner Paul , Kettler Markus , Unterweger Harald
Published: September 2021

In existing crane runways, data on the actual wheel loads acting on the crane rail are often missing. Therefore, approximated wheel loads have often to be assumed for static calculations of the crane runway girder. Within this paper, a method is presented that allows to calculate the actual wheel loads based on strain measurements on the crane rail. The idea is to measure strains on the rail at certain pre‐defined locations, while the crane is passing and calculate the wheel load from the measured strains. The correlation between the strains in the rail and the wheel load is determined in a numerical finite element study and in laboratory tests.

The numerical studies also comprise several different geometries of crane runway girders. The objective is to verify the influences of them on the calculated strains in the rail. The results of the numeric calculations show, that the strains in the rail generally depend on the stiffness of the crane runway girder. The thickness of the upper flange and the web as well were identified as the main parameters. This behavior is also verified in laboratory tests.

For the contact between the rail and the crane runway girder, two different cases have been investigated. The first analysis refers to a hard contact under compression which allows separation under tension. This configuration corresponds to cases with steel wearing plates beneath the crane rails. The second case considers an elastomeric rail pad between the rail and the crane runway girder.
Sustainable Housing Provision: A Case for the Vertical Extension of Steel Framed Buildings
Authors: Gillott Charles , Densley‐Tingley Danielle , Davison Buick
Published: September 2021

The UK is experiencing unprecedented housing demand, with traditional provision in suburbanised clusters now known to have negative environmental, economic and social impacts. An alternative to this is residential densification through vertical extension; generating a more sustainable urban form whilst also serving to increase circularity of material flows within the construction industry and reduce whole‐life carbon and energy requirements. As a result of their relative abundance, inherent durability, and ease of adaptation, multi storey steel framed buildings are particularly pertinent in this context. It is also likely that sufficient reserve structural capacity exists within this typology; resulting from overdesign, the employment of simplified analytic design methods, and the limited number of section sizes available for use. The relative portion of reserve buckling capacity originating from these sources is assessed using a modified version of the effective length method to account for column continuity in multi‐storey steel frames. This reveals the consideration of column continuity to contribute an average of 1.23 kN/m2 of reserve buckling capacity across typical office buildings, with the amount resulting from section size limitations varying with design scenario.
Steel based retrofitting interventions for existing masonry walls: a comparative numerical investigation
Authors: Zizi Mattia , Vari Alessandro , Colajanni Piero , De Matteis Gianfranco
Published: September 2021

Masonry buildings constitute a significant portion of the architectural heritage all over the world, also in regions affected by a high seismic hazard. Since this constructional material is characterized by lack of tensile strength, as well as small deformation capacity, masonry structures could result hugely damaged if shaken by seismic forces. In order to avoid collapses and reduce structural damage, innovative retrofitting interventions are necessary to improve the seismic behavior of masonry structures. In this context, steel‐based techniques could be considered among the most suitable solutions. In fact, by using such a high‐performant material, additional strength and ductility may be conferred to existing masonry structures. Based on these premises, the present paper focuses on a numerical investigation of two different retrofitting techniques: the CAM© system and the application of steel grids on both faces of a masonry wall. In particular, on the base of an experimental test carried out within the research project In.CAM.M.I.N.O. on an unreinforced masonry wall tested in condition of constant vertical force and horizontal loads, a reference FE Model has been calibrated in Abaqus by using a macro‐modelling approach with a damage‐plasticity material model for the masonry. Then, based on the reference model, the efficiency of the two systems has been investigated and compared by means of numerical analyses, in order to evaluate the strength and ductility increases obtainable by the application of the two retrofitting techniques.
Laser tube technology ‐ A new automation procedure in end‐preparation of CHS‐to‐CHS intersections welded by partial joint penetration (PJP): design, constructional and experimental remarks
Authors: Mastropasqua Augusto , Majowiecki Massimo , Duarte Claudio
Published: September 2021

Over the past decade, the manufacturers of the most advanced laser‐cutting machinery have made significant breakthroughs in the CNC (computer numerical control) field, by utilizing the efficiency of the reversible laser‐beam (multi‐axis robotic system). In this paper, welded tubular connections for structural applications are studied with explicit reference to these new end‐machining possibilities. In particular, the case of circular hollow sections (CHS) is dealt with, whereby the class of connection typically referred to is known as CHS‐to‐CHS connections. Thanks to the Laser‐Tube‐Cutting technology (LTC), it is now possible, for Partial Joint Penetration (PJP) or Compound Joint Penetration (FW+PJP) to establish size, position and spatial inclination of the throat‐plane along the welded path, allowing the structural designers to better simulate the real stress distribution through the welded region (WR) and the nominal throat‐plane (TP) surface. The study is concluded with some interesting as‐built case studies and the results obtained from an LTC‐experimental phase aimed at obtaining 5 samples that are wholly compatible to the EN(ISO)9692, AS/NZS1554 and AWS‐D1.1 welding codes.
Effect of weld residual stress on fatigue strength
Authors: Manai Asma
Published: September 2021

Residual stress (RS) refers to the stress permanently present in structures without any external load. This stress can be introduced by different sources, for instance, weld, post‐weld treatment, etc. Weld is a joining process that is associated with intensive heating which leads to considerable change in local material microstructure and the formation of high residual stresses in the welded joint. Residual stress introduces a change in the stress ratio, which means a change in the characteristic of cyclic loading which can have a detrimental effect on the fatigue strength of welded joints. In this paper, an experimental and numerical study of weld residual stress through the thickness direction at the weld toe of transversal attachment made with S355 was investigated. It was found that weld induced compressive residual stress at the surface. In the case where weld induces compressive residual stress, the fatigue life is 4.5 times higher than the standard as‐welded S‐N curve (when tensile residual stress is introduced)
The Effect of Steel Strength on the Behavior of a K‐Joint in a Slim‐floor Truss
Authors: Saremi Pooya , Lu Wei , Puttonen Jari , Pada Dan , Kesti Jyrki
Published: September 2021

This paper studies the applicability of the strain‐limit criterion in the Eurocode 3 to defining the limit load for a K‐type truss joint, which connects two tubular braces to a plate chord. The joint is used in a novel Finnish slim‐floor system with integrated load‐bearing members of High‐Strength Steel (HSS). The Finite‐Element Model (FEM) of the joint is validated by the experimental results of scaled‐down, isolated joint specimens made of S420 and S700 steel. The validated FEM is used to study the failure of the joint and the effect of steel strength on the failure mode. For the specific geometry of this joint, the criterion based on the 5% strain limit proposed by the Eurocode 3 was found to be well justified for the steel grades S235 and S355 and reasonably applicable to the steel grades S460 and S550. However, the results indicated that the value of 5% for the strain limit was too large, if the joint was made of the S690 steel grade.
Numerical analysis of the stress‐strain behaviour in statically determinate composite steel‐concrete beam after 100 years creep phenomena process using Volterra Integral Equations
Authors: Kazakov Konstantin , Stoyanov Chavdar , Partov Doncho , Kantchev Vesselin
Published: September 2021

The paper presents a precise analysis of the stress‐strain behaviour due to creep in statically determinate composite steel‐concrete beam according to numerical method in comparison with EM method of Dischinger. The analysis is based on the results obtained by numerical solution with Volterra integral equations, derived for determining the redistribution of stresses in beam section between concrete plate and steel beam with respect to time “t”. The creep law of concrete, according EC2 provisions is used. On the basis of the theory of the viscoelastic body of Arutyunian– Trost‐Bažant it is analyzed the migration of stresses from concrete plate to steel beam using two independent Volterra integral equations of the second kind. The duration of the course of study was adopted 100 years. Developed method will allow soon be confronted methods for calculating the composite beams according to EC4 considering rheology of concrete, based on the reduced elastic modulus of concrete.
Recent Advances in the Syntheses and Catalytic Applications of Homonuclear Ru‐, Rh‐, and Ir‐Complexes of CNHC^C Cyclometalated Ligands
Authors: Tiwari Chandra Shekhar , Illam Praseetha Mathoor , Donthireddy S. N. R. , Rit Arnab
Published: September 2021

In the past few decades, chemistry of cyclometalated species has gained momentum with increased applications in several areas of scientific developments. Cyclometalation reactions result in the formation of stable metallacycles through the generation of metal‐carbon covalent bonds by activating the unreactive Csp2‐H or Csp3‐H bonds. The extra stability gained by the formation of metallacycles enhances their applicability scopes especially in the area of homogeneous catalysis. In the recent research development in this area, NHC ligands (strong σ‐donor and generally, weak π‐acceptor) have been found to be one of the most suitable candidates for the intramolecular C−H activation process which leads to the cyclometalated species. The growth in the area of cyclometalation chemistry that started in the late 20th century is still continuing and in the past few decades, various examples of NHC derived transition metal‐based cyclometalated complexes came into the picture. As covering all the reported literatures in this area (includes mainly late transition metals) will exceed the limits of minireview, we restricted ourselves to the recent (2015 – May 2021) examples of the most common Ru‐, Rh‐, and Ir‐based CNHC^C cyclometalated complexes and their applications in various homogeneous catalytic conversions such as transfer hydrogenation, amidation, oxidation of alcohols, annulations, and so forth.
Direct Synthesis of Tri‐/Difluoromethyl Ketones from Carboxylic Acids by Cross‐Coupling with Acyloxyphosphonium Ions
Authors: Ispizua‐Rodriguez Xanath , Munoz Socrates B. , Krishnamurti Vinayak , Mathew Thomas , Prakash G. K. S.
Published: September 2021

A simple and straightforward approach to the synthesis of trifluoromethyl and difluoromethyl ketones from widely available carboxylic acids is disclosed. The transformation utilizes an acyloxyphosphonium ion as the active electrophile, conveniently generated in situ from the carboxylic acid substrate by using commodity chemicals. The utility of the reaction system is exemplified by its chemoselectivity, with tolerance to a variety of important functional groups. The late‐stage functionalization of carboxylic acid active pharmaceutical ingredients and pharmaceutically relevant compounds is also discussed.
Single Amino‐Acid Based Self‐Assembled Biomaterials with Potent Antimicrobial Activity
Authors: Misra Souvik , Mukherjee Soumyajit , Ghosh Anamika , Singh Pijush , Mondal Sanjoy , Ray Debes , Bhattacharya Gourav , Ganguly Debabani , Ghosh Alok , Aswal V. K. , Mahapatra Ajit K. , Satpati Biswarup , Nanda Jayanta
Published: September 2021

The design and development of soft biomaterials based on amino acid and short‐peptide have gained much attention due to their potent biomedical applications. A slight alteration in the side‐chain of single amino acid in a peptide or protein sequence has a huge impact on the structure and function. Phenylalanine is one of the most studied amino acids, which contains an aromatic phenyl group connected through a flexible −CH2− unit. In this work, we have examined whether flexibility and aromatic functionality of phenylalanine (Phe) are important in gel formation of model gelator Fmoc‐Phe‐OH or not. To examine this hypothesis, we synthesized Fmoc‐derivatives of three analogues unnatural amino acids including cyclohexylalanine, phenylglycine, and homophenylalanine; which are slightly varied from Phe. Interestingly, all these three new analogues formed hydrogels in phosphate buffer at pH 7.0 having different gelation efficacy and kinetics. This study suggests that the presence of aromatic side‐chain and flexibility are not mandatory for the gelation of this model gelator. Newly synthesized unnatural amino acid derivatives have also exhibited promising antimicrobial activity towards gram‐positive bacteria by inhibiting cellular oxygen consumption. We further determined the biocompatibility of these amino acid derivatives by using a hemolysis assay on human blood cells. Overall studies described the development of single amino acid‐based new injectable biomaterials with improved antimicrobial activity by the slight alteration in the side‐chain of amino acid.