bluuebunny/crossref_metadata_2025 huggingface dataset:
Local buckling of WAAM stainless steel circular columns
Authors: Huang Yanan , Yang Lu , Liu Meiyu , Xu Kelong
Published: September 2023

Wire and Arc Additive Manufacturing (WAAM) is one of the promising metal 3D printing techniques, with the ability to produce large‐scale structural components with high speed and low cost. However, there is a lack of research on the structural performance of WAAM members. To this end, numerical modeling and design of WAAM stainless steel circular hollow section (CHS) stub columns has been conducted. Finite element (FE) models considering both as‐built material properties and rough geometry were proposed and verified by the existing experimental studies. By using the FE models, parametric studies on the local buckling resistance of WAAM CHS stub columns were conducted to consider a wider range of specimen geometries. Based on the FE results, the applicability of the current column design provisions in EN 1993‐1‐4 and AISC 370 to WAAM stainless steel CHS stub columns was assessed. At last, a new modified method was proposed to predict the local buckling resistance of WAAM stainless steel CHS stub columns. This study provides a novel approach for the FE modelling of WAAM components.
Feasibility study on stub and slender veneer‐wrapped steel columns
Authors: Vigneri Valentino , Taras Andreas
Published: September 2023

The paper presents a newly developed steel‐timber composite column, called “STIMBER‐COL”, which is made of an inner hollow section wrapped by several veneer layers glued together. In addition to the well‐known environmental benefits, the potential advantages at mechanical level are thoroughly discussed in consideration of the literature available. In view of the promising experimental results on steel‐timber composite columns reported in recent studies, a foreseen experimental campaign of 5 stub and 3 slender columns is described along with the setup and instrumentation. Special emphasis is given to the manufacturing process which represents a challenging step in this feasibility study. The test results confirm that the veneer layers lead to a significant increase in stiffness and strength. The work is conducted in the frame of an applied research project to support more advanced research and the implementation of the market in the future.
Second Generation of Eurocode 8: Seismic Design Rules for Cold‐Formed Steel Buildings
Authors: Landolfo Raffaele , Fiorino Luigi
Published: September 2023

The seismic design of Cold‐Formed Steel (CFS) building structures is not covered by the current edition of Eurocode 8. In order to update Eurocode 8 to reflect the findings of extensive research undertaken over the last ten years, the University of Naples “Federico II” is taking part in the evaluation of current seismic design criteria and the creation of new guidelines for the design of CFS systems. This paper especially examines various Lateral Force Resisting System (LFRS) types that may be found in the second version of Eurocode 8. It also provides background information on the research initiatives and reference design standards in use in various parts of the world that served as the basis for the development of design criteria included in the new version of Eurocode 8.
Numerical investigations of the load‐bearing and fatigue behavior of orthotropic composite slabs for road bridges
Authors: Lewerenz Camilla , Shirinzadeh Mozhdeh , Stroetmann Richard
Published: September 2023

Fatigue damage to existing steel bridges occurred due to the large increases in traffic loads and the notch sharpness in the details of orthotropic steel roadway slabs. The development of the orthotropic‐composite‐slab (OC‐slab) provides an alternative durable and lightweight composite construction. As part of the AIF‐FOSTA research project P1265 [1], the orthotropic‐composite‐slab for road bridges is currently being investigated at the Technische Universität Dresden. The project aims to develop fundamentals for the design of OC‐slabs with dowel strips. The investigations create important foundations for the establishment of the innovative construction method as an economical and durable alternative. The papers [2] and [3] give an overview of the construction and the load bearing behavior of the OC‐Slab, the paper [4] details about the experimental test program. This paper describes the numerical investigations carried out. They complement the experimental tests and provide additional knowledge about the load‐bearing and fatigue behavior of the OC‐slabs with dowel strips. The focus is on the presentation of the numerical simulation of the beam test and the determination of the ultimate and fatigue strength of the structure.
Decarbonisation of steel production by the low‐carbon DRI‐EAF route
Authors: Gervásio Helena , da Silva Luís Simões
Published: September 2023

The effects of climate change, induced by global warming, are leading to huge economic, environmental and social impacts worldwide. The world is considered to be in a state of climate emergency, and urgent decarbonisation measures are required to control the temperature rise and mitigate such effects. In this context, EU targets for decarbonisation are to reduce, at least 55% of GHG emissions until 2030, and then to become climate‐neutral, by 2050. The steel industry, being among the biggest producers of CO2, is committed to fulfil this goal. However, the production of 1 tonne of steel, in the coal‐dependent BF/BOF route, can lead to about 2.3 tonnes of CO2, and this route is responsible for more than half of all steel produced in EU. Therefore, finding alternative breakthrough technologies to reduce CO2 emissions is a priority for the steel industry, and different decarbonisation strategies are being implemented in different European plants. Such strategies include the optimization of the DRI and EAF route. This paper focused on this strategy and it was found that the combined route DRI and EAF, based on green hydrogen and carbon free electricity, may reduce CO2 emissions in about 98% compared to the BF/BOF route.
Fire exposure measurements using plate thermometers
Authors: Malendowski Michał , Szymkuć Wojciech , Daszkiewicz Tomasz , Turkowski Piotr , Węgrzyński Wojciech
Published: September 2023

Plate thermometers (PT) are known and utilized in fire testing for more than 30 years. They are simple devices that measure the temperature of the thin plate, made of a thermal conductor, that is exposed to fire from one side and insulated from the opposite side. The main advantage of measuring thermal exposure using a plate thermometer is its ability to capture both the convective and radiative parts of the heat flux. However, thermal exposure is not directly the value the plate thermometer outputs. For this reason, an adiabatic surface temperature (AST), which could be considered as an objective measure of thermal exposure, can be calculated on the basis of the plate thermometer output. In this work, the abilities for fire‐exposure measurements using plate thermometers are discussed.

This work introduces the closed‐form analytical solution of the plate thermometer heat balance equation for an adiabatic surface temperature. The authors consider the introduced solution as the best method, at this moment, for the evaluation of AST based on the PT output. This allows several findings to be presented that are not affected by the shortcomings of previously used methods for the AST evaluation.
Experimental response of full‐scale steel‐aluminium foam‐steel sandwich panels in bending
Authors: Sato Atsushi , Latour Massimo , D'Aniello Mario , Rizzano Gianvttorio , Landolfo Raffaele
Published: September 2023

The introduction of metal foams into the building market represents a significant opportunity to increase the use of metal in construction. Developing new structural products made of metal foams and steel could improve conventional buildings' performances in terms of stiffness and resistance. Steel or aluminium foams are characterised by mechanical properties similar to glulam timber, combined with a high energy dissipation capacity. These peculiarities allow conceiving new composites with features typical of the bio‐mimetic materials: lightness, compactness, dissipation, resistance and stiffness. The first structural applications of these materials have already shown the potentialities of composites made of foam and steel, verifying the possibility to realise mono‐dimensional and bi‐dimensional elements with exceptionally high resistance‐weight ratios. Reducing the structural weight can represent a significant advantage in many cases, such as for buildings in the seismic zone or for infrastructures. Within this framework, this preliminary work paper aims to analyse the response of full‐scale metallurgically bonded sandwich panels made of steel and aluminium foam with three‐point bending tests. From the testing, it was confirmed that the metallurgically bonded sandwich panels reach the full‐plastic strength that is computed from the rigid‐plastic material assumption. Moreover, the sandwich panel's bending stiffness can be easily calculated according to the Navier hypotheses. The ultimate limit state of the sandwich panel was determined by the plastic hinge formation of the panel section; fracture between the aluminium foam and the steel sheet was not observed (except the layer where the it was initially detached). The potential performance of the metallurgically bonded sandwich panel that can be used for the civil engineering application was verified from this testing.
Calibrated Design of High Strength Composite Columns
Authors: Kelpša Šarūnas , Beckmann Oliver , Guobys Raimondas , Schurgacz Przemyslaw , Augonis Mindaugas
Published: September 2023

What does the general design method, described in EN 1994‐1‐1, mean in practice for the construction industry? Even though this method requires additional efforts, it provides improved design accuracy. High strength and high slenderness concrete filled steel tube composite columns with a solid steel core inside have undoubtable benefits. However, application of such columns requires the use of a general method of design and special knowledge not fully covered by Eurocodes.

In order to utilize the general design method for ATLANT® Strong composite columns, Peikko has conducted an extensive development program. During the program, multiple tests were conducted on materials and the columns itself. The test results were used to calibrate models of Finite Element Analysis (ABAQUS), which allowed to investigate the behaviour of those columns even more extensively. Eventually, the general design method was implemented and calibrated, allowing reliable and optimized design.

The paper contains an overview of ATLANT® Strong composite columns behaviour, the extensive testing program and calibration process to reach the optimal design of such columns. Additionally practical specifics, challenges and benefits are discussed.
Flexural behaviour of CFS stacked built‐up beams: experiments, finite element modelling and direct strength method
Authors: Rezaeian Hooman , Andarini Rhonita
Published: September 2023

This paper presents the initial results and findings from the experimental and numerical study of recently developed CFS stacked built‐up beams. The specimens are constructed by joining either three or four 75×150 lipped channel sections using screws. A cap of LC 89×41.3 with a nominal thickness of 1.2 mm screwed to the open flange to provide a closed section with a greater flexural capacity. A six‐point loading system was considered to study the flexural behavior of these built‐up beams. The load‐displacement curves, strength and failure modes are reported. A nonlinear elastic‐plastic finite element (FE) model is developed. The bending strengths are also calculated using the direct strength method (DSM) in the North American Specification (AISI) and Australian/New Zealand Standard (AS/NZs) for cold‐formed steel structures. Both results obtained from the FE and the direct strength methods are compared against the experimental.
Simplified Nonlinear Dynamic Analysis by Hexagonal Collapse Surface Model of Steel Frame Structure
Authors: Jainih Viliana , Choi Jae Hyouk
Published: September 2023

Based on the need for effective evaluation of multistorey structures response to seismic loading, this research includes the study of simplified nonlinear dynamic analysis (SNDA) by hexagonal collapse surface model. Existing conventional analysis methods such as FEMA440, restrict the extended use of Nonlinear Static Procedure (NSP) and Nonlinear Dynamic Procedure (NDP) by using the equivalent one‐degree‐of‐freedom (SDOF) model on multi‐degree‐of‐freedom (MDOF) structure. A large error known as Multiple‐Degree‐of Freedom Effects occurs in the elastoplastic behavior. To overcome the limitations of this analysis technique, the understanding of it in the entire structural system due to the influence of the higher‐order vibration modes are investigated, in addition to distinguish the elastoplastic behavior of a structure more precisely. Based on the important collapse mechanisms that are probable to occur during earthquake response, the development of a simplified dynamic analysis technique in which higher‐order vibration mode components were extracted to construct the plastic collapse safety region of a structure. Simplified nonlinear dynamic analysis (SNDA) aims to develop such method whereby multiple vibration mode components are properly considered. Primary and secondary mode of vibrations are generally examined with multiple load patterns corresponding to the condition whereby several independent variables reach maximum concurrently. The formation of hexagonal plastic collapse surface from the probability limit analysis based on proportional load results was discussed. The target for this study is to investigate the competency of this simplified analysis approach in seismic response of structure evaluating techniques.
Simplified method for the vibration comfort assessment of steel‐concrete floors induced by crowd‐rhythmic activities
Authors: Asri Youssef El , Denoël Vincent , Couchaux Maël , Hjiaj Mohammed , Lukić Mladen
Published: September 2023

This paper presents a design‐oriented method for a simplified prediction of the vibrational response of regular floors induced by crowd‐rhythmic activities. The method is based on a frequency domain load model, along with the stochastic vibration theory. An application of the method is illustrated on an existing steel‐concrete composite floor belonging to an open‐plan office, with a total area of about 385m2. Four rhythmic activities with experimentally identified load parameters are investigated. The individuals performing these activities are assumed to be uniformly distributed over the floor, with their numbers ranging between 1 and 64. The prediction of the floor response reveals that the floor presents tolerable levels of acceleration for up to 16 persons in general, while remedial measures should be undertaken to reduce the response of the floor subjected to larger crowd sizes. The proposed method might represent a first step in the development of the floor serviceability assessment for vibration comfort in the forthcoming editions of Eurocodes for practical application.
Fatigue performance evaluation of stiffener‐to‐deck plate weld in orthotropic steel decks based on generative adversarial network
Authors: Liu Bingfeng , Xin Haohui , Liu Jielin , Veljkovic Milan
Published: September 2023

The stiffener‐to‐deck plate welds are one of the weak areas of orthotropic steel decks (OSDs). Accurate evaluation of fatigue performance of stiffener‐to‐deck plate welds is important for the design and service of OSDs. Traditional fatigue performance evaluation method of stiffener‐to‐deck plate welds based on S‐N curves requires a large amount of experimental data as support. However, fatigue tests are time‐consuming and costly‐approach. In this paper, generative adversarial network (GAN) was used to augment hot spot stress range data and fatigue life of rib‐to‐deck welded joints based on a small amount of test data. Then, the least‐squares regression was used to fit S‐N curves base on original data and generated data. The fitted S‐N curves were compared with experimental curve. Compared with the S‐N curve fitted by a small amount of original data, the S‐N curve fitted by generated data is closer to the experimental result, which indicates that the fatigue data generated by GAN has the potential to be an effective tool in the fatigue performance evaluation of fatigue critical details.
Optimisation of the damping properties of steel structures using adhesively bonded joints
Authors: Damm Jannis , Albiez Matthias , Ummenhofer Thomas
Published: September 2023

Adhesives offer both good damping properties and very high strengths. The possibilities for using the positive damping properties in particular to optimise dynamically stressed steel structures have rarely been explored to date. In this paper, comprehensive numerical and experimental investigations are presented. In numerical investigations on dynamically loaded, representative steel structures, the potential for damping of structures by adhesively bonded joints is analysed. Numerical investigations show that the vibration amplitudes of adhesively bonded structures are more than 95 % lower than those of welded reference structures in the relevant resonance case. Based on this, the damping properties of adhesively bonded tubular steel joints in a scale relevant for construction industry were experimentally investigated. Different geometry and test boundary conditions are investigated in a parameter study. The loss factor of tubular joints is a maximum of 0.38, which is relevant for steel construction. Based on the results of experimental investiga‐tions, a methodology is presented for the analytic determination of the damp‐ing properties of adhesively bonded tubular joints for various specimen ge‐ometries and stress boundary conditions. For this purpose, dimensional anal‐ysis is carried out using the Buckingham Pi Theorem.
Effect of heat treatment on microstructure and pseudoelasticity of a memory‐steel
Authors: Mohri Maryam , Leinenbach Christian , Lignos Dimitrios G. , Ghafoori Elyas
Published: September 2023

The pseudoelasticity behavior of memory‐steels has recently gained attention for applications in seismic‐resistant structures. The pseudoelasticity can be used to reduce residual deformations in building structures subjected to seismic loading. Fe‐based shape memory alloys (Fe‐SMA), which is also called as memory‐steel, have gained much attention because of their strong shape memory behavior and low material manufacturing cost, which justify their large‐scale application in construction. This research investigated the effects of heat treatment on microstructure and pseudoelasticity of a memory‐steel (Fe‐17Mn‐5Si‐10Cr‐4Ni‐1(V,C) %wt.). Various solution‐annealing treatments from 1000 to 1200 °C for 2 h and aging from 650, 750 and 850 °C were applied to investigate the microstructural evolution and pseudoelasticity behavior of the alloy. The results showed that increasing the solution annealing temperature caused grain growth and pseudoelasticity loss. On the other hand, the precipitation of (Cr,V)Cs after aging resulted in an improved pseudo‐elasticity. The large elastic strain field, which forms near the carbide precipitates, improves the pseudoelasticity. Furthermore, precipitates can provide preferential nucleation sites for the martensite phase and a high density of stacking faults in the austenite matrix. The study concludes that the best pseudoelasticity behavior was achieved after an aging at 750°C for 6 h.
Seismic behaviour of high‐strength steel bolted extended end‐plate connections
Authors: Hu Fangxin , Wang Zhan
Published: September 2023

Cyclic loading tests on 690MPa high‐strength steel bolted extended end‐plate connections were conducted to quantify their plastic resistance and plastic rotational capacity under seismic loading conditions. It was found that current formulae in Eurocode 3 Part 1‐8 still arrived at good predictions on plastic resistance of those connections. It was demonstrated that given the bolt grade and diameter, the end plate with an intermediate thickness led to the largest plastic rotation. Such an intermediate, or optimal, end‐plate thickness indicates that the upper limit of the end‐plate thickness, which is now specified in Eurocode 3 Part 1‐8 to ensure a sufficient rotation capacity, should be levered up by about 40% for 690MPa high‐strength steels in seismic design. In such a manner, the maximum plastic rotation of the high‐strength steel end plate was around 0.02rad. In addition, the high‐strength steel shear panel was able to develop a plastic rotation of at least 0.035rad, thus qualified as high‐ductility class (DCH) in Eurocode 8. The weak shear panel contributed for more than 70% of the total plastic rotation capability.
Effect of Intermediate Stiffeners in an Optimization of Axially Compressed Built‐up Thin‐Walled Column Cross‐Sections According to the Eurocode 3
Authors: Sulpinas Mantas , Daniūnas Alfonsas
Published: September 2023

This paper aims to propose an optimized thin‐walled built‐up cross‐section for axially compressed columns, which can be feasibly produced and utilized in building assemblies. The European standard Eurocode 3 [1] was employed, along with an optimization solving algorithm, to calculate the performance of axially compressed thin‐walled columns. The analysis considered the buckling capacity of the column, encompassing local, distortional, and global buckling modes. 3 types of box cross‐sections were examined: without web stiffeners, with web stiffeners bent inwards, and with web stiffeners bent outwards. The cross‐sections were constructed by connecting 2 “C” type or “Sigma” type profiles through their flanges. In the calculations, the thickness of the overlapping parts of the flanges was assumed to be equal to the thickness of the profiles. Experimental investigations have shown that this assumption, where the overlapping parts of the flanges are considered equal to the profile thickness, is conservative and reliable [2]. Consequently, the built‐up cross‐section can be treated as one rigidly connected entity [3]. The results of the calculations reveal that the optimized built‐up axially compressed column cross‐section with web stiffeners exhibits a higher level of effectiveness, with a cross‐sectional area up to 23% smaller compared to the optimized cross‐sectional area of columns without web stiffeners.
On the assessment of non‐conformities. Is execution of steel structures a craft with zero defect tolerance?
Authors: Volz Michael , Spannaus Max , Nagel Sven
Published: September 2023

Is a non‐conformity in the weld seam of a bridge a reason to refuse acceptance or even a safety risk? Behind this lies the controversially discussed question of whether non‐conformities to the technical design standards, e.g. the evaluation groups according to DIN EN ISO 5817, constitute “acceptance criteria” or “quality guidelines” for steel construction. Often the economic success of a project depends on the answer to this question. Nevertheless, there is currently no uniform procedure on how to deal with deviations and which methods are permitted in addition to reworking or rejecting components to prove usability. This regulatory gap is unsatisfactory for all project participants and the subject of many legal disputes. Particularly due to the simplified applicability and the increasing sensitivity of non‐destructive testing methods and the associated partly detective checks of steel structures, irregularities are detected that no longer reflect the original quality‐assuring idea of non‐destructive testing. The actual component function thereby recedes into the background and the question arises as to whether one can or even must demand zero‐defect tolerance from steel construction as a craft. In our article we go into the background of these questions and give recommendations for action based on our project experience, which should help to carry out even large and complex projects to everyone's satisfaction. Using individual examples, we show the connection between design rules and execution standards and explain the possibilities in the evaluation of detected non‐conformities.
Structural behavior of sigma‐type thin‐walled cold‐formed steel beams reinforced with CFRP textile
Authors: Rzeszut Katarzyna , Dybizbański Maciej Adam
Published: September 2023

The purpose of the research presented in this article was to verify the advanced numerical model. The model was made in ABAQUS software using the finite element method (FEM). The verification consisted of comparing the force‐displacement relationship for the numerical model and results from full‐scale laboratory tests. The research conducted concerns the strengthening of thin‐walled cold‐formed steel sigma beams with CFRP mats. The originality of the proposed strengthening method lies in the fact that the mats are bonded across the cross‐section to form a segmental closed cross‐section. Full‐scale laboratory tests were conducted on three Σ200×70×2 beams subjected to four‐point bending. SikaWrap 230 C CFRP mats and SikaDur 330 adhesive were used to reinforce the beams. The mats were applied to the edge bends of the beams at a width of 300 mm. It was stated that the current numerical model, despite its high degree of sophistication, does not fully meet the conditions obtained in the laboratory.
Numerical Behaviour of Blind‐Bolted Beam Connections to Square Hollow Sections with Different Infills
Authors: Gunes Sahin , Theofanous Marios , Skalomenos Konstantinos , Baniotopoulos Charalampos
Published: September 2023

This paper reports the development and validation of an advanced FE model that can predict the overall behaviour and failure modes of blind bolted T‐stub to unfilled tube (UT), concrete‐filled tube (CFT) and foam‐filled tube (FFT) joints in tension. The joints investigated were made of S355 Square Hollow Sections (SHS) either empty or with concrete or polyurethane infill, connected to a rigid T‐stub using HB 10 hollow bolts. Associated experimental results are used for model validation purposes. The main modelling assumptions and relevant simulation strategies in terms geometric and material modelling are discussed and the resulting models are shown to accurately replicate the experimentally observed response in terms of yield load, failure load, observed failure modes and available ductility of the connections. The favourable performance of connections employing SHS with a polyurethane infill compared to the empty and concrete filled SHS in terms of both strength and ductility is highlighted.
Length and Boundary Condition Effects in the Buckling of Cylinders Under Different Load Combinations
Authors: Al‐Lawati Hussain , Al‐Balushi Abdullah , Al‐Habsi Abdulrahman
Published: September 2023

The newest version of shells buckling standard prEN 1993‐1‐6 (2021) adopts linear elastic buckling stress expressions for steel perfect cylinders under axial, circumferential, and torsional effects separately. However, there are no explicit detailed rules that cover the influence of two or more loading combinations on the cylinder buckling resistance, considering a full‐length domain and different boundary conditions. Consequently, this paper looks into such a topic, which will be a useful reference for future research extensions. The examined cylinders were subjected to three loading configurations: axial plus pressure, axial plus torsion, and axial, pressure, and torsion altogether. The finite element (FE) buckling capacities were compared with the prEN 1993‐1‐6 (2021) buckling strengths, from which several findings were obtained. Aspects such as the load configuration applied to a cylinder, the length domain in which a cylinder falls, and the boundary type of a cylinder's ends each led to distinctive and complex descriptions of buckling behavior. The outcomes of this study will in turn assist in developing the current standard prEN 1993‐1‐6 (2021) and its recommendation ECCS EDR5 (2013), particularly the chapter that is relevant to cylindrical shells of constant wall thickness under general loading.
Progressive collapse analysis of steel frames via a nonlinear SDOF model
Authors: Dimopoulos Christoforos
Published: September 2023

Progressive collapse is a dynamic loading incident triggered by the sudden loss of critical elements. Design codes provide simplified rules to consider the dynamic effects via the use of Dynamic Increased Factors in order to avoid complex and time‐consuming nonlinear time history analyses. In this paper, a nonlinear single degree of freedom (SDOF) system is presented that captures the dynamic response of steel frames subjected to a column removal scenario. The model takes into account inertia, damping effects and assumes an elastoplastic nonlinear resistance for the system. A closed‐form analytical solution for the dynamic equation of motion is derived and then is applied to a frame to simulate the response under a column removal scenario. A nonlinear finite element model developed in OpenSees was used to verify the accuracy of the analytical model. The results showed that the nonlinear response of the frame for the selected hazard event can be well captured with the proposed model.
The influence of hinged and rigid connections on the seismic behaviour of “Inverted Y” bracing systems
Authors: Köber Helmuth , Stoian Marina , Marcu Ramona
Published: September 2023

The present paper intends to illustrate the seismic behaviour of different configurations for a ten storeyed “inverted Y” eccentrically braced frame provided with rigid and/or pined beam/column and diagonal/column connections. Four configurations were analysed for the “inverted Y” braced frame, sized for the forces produced by the same code seismic base shear force. In the first configuration, rigid connections were used for all kind of structural elements. The second configuration had hinged beam/column and diagonal/column connections. In case of the third configuration, rigid connections were used among all kind of structural elements and additional potentially plastic zones with reduced cross‐sections (resembling the “dog‐bone” detail) were considered along the girders and braces, near the member ends connected to the columns. The fourth configuration had hinged diagonal/column connections and additional potentially plastic zones were considered only along the frame girders, near the girder ends connected to the columns. The behaviour of each frame configuration during static and dynamic nonlinear analyses was observed. The extreme values for deformations and member forces were compared. The steel consumption was estimated for each of the four considered configurations.
Development of Improved Equations for Live Load Moment Distribution in Interior Girders of Shallow Steel Tub Girder Bridges
Authors: Barth Karl , Michaelson Gregory , Pyrialakou V. Dimitra , Woldegabriel Brook , Mason Joshua
Published: September 2023

The focus of this paper is the development of improved live load distribution factor (LLDF) prediction equations for interior beams of press‐brake‐formed tub girder (PBFTG) bridges. PBFTGs consist of cold‐bent standard plate widths and thicknesses to form a trapezoidal box girder. Based on a survey of literature and field testing performed on PBFTG bridges across multiple states in the United States, the empirical equations found in the American Association of State Highway and Transportation Officials Load Resistance and Factor Design Bridge Design Specifications (AASHTO LRFD BDS) have been found to be conservatively applicable to shallow steel tub girder bridges. Improvements can be made to AASHTO LRFD BDS provisions relating to shallow steel tub girders and their respective live load distribution factors (LLDFs). To overcome this gap in design and analysis, rigorous three‐dimensional finite element analysis tools were developed and benchmarked against field implementations. The tools were used to analyze the live load distribution behavior of an interior girder of a matrix of approximately 18,000 PBFTG bridges. From the result of the analysis, statistical methods were employed to produce simplified empirical equations to better predict live load moment distribution in PBFTGs. The simplified equations are to be used in conjunction with line girder analysis to further simplify the design of shallow steel tub girder bridges and expand their application in the short‐span bridge market.
Experimental Investigation of Seismic Vulnerability of Braces under Hazard Consistent loading sequences
Authors: Patra Pratik , Sahoo Dipti Ranjan , Jain Arvind Kumar
Published: September 2023

In the last ten years, Chile and Japan have experienced several subduction earthquakes that lasted for extended periods of time. These occurrences have emphasized the need for a thorough examination of how the duration of ground motion impacts the performance of the components of the lateral load resisting system. In the present study, three large‐scale experiments were conducted on the wide‐flange brace member to evaluate the seismic vulnerability of the braces under the hazard consistent loading protocol. The loading sequences consider in the study are standard symmetric cyclic loading sequences, collapse‐consistent loading sequences representing subduction zone tension dominated and collapse‐consistent loading sequences representing subduction zone compression dominated. The subassemblage test‐set‐up was taken in the study to consider the effect of the end‐protect zone on the seismic assessments of the brace members. The evolution of strain at the mid‐section of the brace member is observed to be higher in case of the standard loading sequences as compared to the subduction zone loading sequences. The post yielding stiffness and the collapse resistance of the brace member under the subduction zone earthquake are present. The damage state of the open section brace member and evolution of the local bucking at the mid of the brace member were discussed. It is observed that open section delays the accumulation of strain at brace member and delay the fracture initiation. The ductility of the different brace members is compared to highlight the influence of the cross‐section properties of the brace on the ductility of the braced system.
Alternating Stereospecificity upon Central‐Atom Change: Dynamics of the F−+PH2Cl SN2 Reaction Compared to its C‐ and N‐Centered Analogues
Authors: Giricz Anett , Czakó Gábor , Papp Dóra
Published: September 2023

Central‐atom effects on bimolecular nucleophilic substitution (SN2) reactions are well‐known in chemistry, however, the atomic‐level SN2 dynamics at phosphorous (P) centers has never been studied. We investigate the dynamics of the F−+PH2Cl reaction with the quasi‐classical trajectory method on a novel full‐dimensional analytical potential energy surface fitted on high‐level ab initio data. Our computations reveal intermediate dynamics compared to the F−+CH3Cl and the F−+NH2Cl SN2 reactions: phosphorus as central atom leads to a more indirect SN2 reaction with extensive complex‐formation with respect to the carbon‐centered one, however, the title reaction is more direct than its N‐centered pair. Stereospecificity, characteristic at C‐center, does not appear here either, due to the submerged front‐side‐attack retention path and the repeated entrance‐channel inversional motion, whereas the multi‐inversion mechanism discovered at nitrogen center is also undermined by the deep Walden‐well. At low collision energies, 6 % of the PH2F products form with retained configuration, mostly through complex‐mediated mechanisms, while this ratio reaches 24 % at the highest energy due to the increasing dominance of the direct front‐side mechanism and the smaller chance for hitting the deep Walden‐inversion minimum. Our results suggest pronounced central‐atom effects in SN2 reactions, which can fundamentally change their (stereo)dynamics.
Tracking SF5I in the Iodopentafluorosulfanylation of Alkynes
Authors: Nguyen Thi Mo , Legault Claude Y. , Blanchard Nicolas , Bizet Vincent , Cahard Dominique
Published: September 2023

In the vibrant field of SF5 chemistry, SF5X reagents (X=F, Cl, Br) are at the heart of current investigations in radical pentafluorosulfanylation reactions. SF5I is the missing link whose existence has not been reported despite its potential as SF5 donor. This study reports the formal addition of the hitherto unknown SF5I reagent to alkynes by means of a combination of SF5Cl/KI/18‐crown‐6 ether. The exclusive regio‐ and stereoselective synthesis of unprecedented (E)‐1‐iodo‐2‐(pentafluoro‐λ6‐sulfanyl) alkenes was achieved. A consensus was reached through computational and mechanistic studies for the realistic formation of SF5− anion but not SF5I in solution and the rational involvement of SF5⋅ and iodine radicals in the iodo pentafluorosulfanylation reaction.
Treatment of textile dye wastewater by peroxymonosulfate activation using facilely prepared Fe3O4@TiO2 heterogeneous photocatalyst
Authors: Thuy Nguyen Thi , Tien Nguyen Thi Cam , Anh Huynh Ngoc Chau , Hoang Ngo Du Thai , Dung Nguyen Trung , Huyen Trinh Thi Bich , Thuy Vo Thi Thanh , Hien Lam Pham Thanh , Van Thanh Dang , Huy Nguyen Nhat
Published: September 2023

In this study, Fe3O4@TiO2 was synthesized by a facile precipitation–impregnation method and applied as a magnetic photocatalyst for degrading synthetic and actual textile dyeing wastewater in the presence of peroxymonosulfate (PMS). In Rhodamine B (RhB) degradation, the removal efficiency reached 99.86% (for RhB) and 93.67% (for color) under optimal operating conditions of 80 mg L–1 RhB, 0.5 g L–1 PMS, 0.5 g L–1 Fe3O4@TiO2, at pH 6, and after 30 min of UVA irradiation. The influence levels of anions on the RhB removal and decolorization were in the order of Cl− < SO42− < CO32− < PO43−. In addition, the Fe3O4@TiO2 composite exhibited good applicability for treating other dyes (e.g., 99.6% of tartrazine and 60.3% of methylene blue after 30 min) in water and actual textile dyeing wastewater with high color (70.3% after 5 min) and COD removal (71.4% after 120 min). The radical scavenging tests indicated the role of reactive oxygen species in the order of O2•− ∼ 1O2 > h+ > SO4•− > HO• for RhB degradation but O2•− > h+ > 1O2 > SO4•− > HO• for decolorization. These results suggest the potential application of PMS activation using Fe3O4@TiO2 in the photocatalytic treatment of textile and dyeing wastewater with the dominant role of O2•−.
Antimalarial Agents Targeting Plasmodium falciparum Carbonic Anhydrase: Towards Artesunate Hybrid Compounds with Dual Mechanism of Action
Authors: D'Agostino Ilaria , Zara Susi , Carradori Simone , De Luca Viviana , Capasso Clemente , Kocken Clemens H. M. , Zeeman Anne‐Marie , Angeli Andrea , Carta Fabrizio , Supuran Claudiu T.
Published: September 2023

Malaria continues to be a major public health challenge worldwide and, as part of the global effort toward malaria eradication, plasmodium carbonic anhydrases (CAs) have recently been proposed as potential targets for malaria treatment. In this study, a series of eight hybrid compounds combining the Artesunate core with a sulfonamide moiety were synthesized and evaluated for their inhibition potency against the widely expressed human (h) CAs I, II and the isoform from P. falciparum (PfCA). All derivatives demonstrated high inhibition potency against PfCA, achieving a KI value in the sub‐nanomolar range (0.35 nM). Two Compounds showed a selectivity index of 4.1 and 3.1, respectively, against this protozoan isoform compared to hCA II. Three Derivatives showed no cytotoxic effects on human gingival fibroblasts at 50 μM with a high killing rate against both P. falciparum and P. knowlesi strains with IC50 in the sub‐nanomolar range, providing a wide therapeutic window. Our findings suggest that these compounds may serve as promising leads for developing new antimalarial drugs and warrant further investigation, including activity against antimalarial‐resistant strains, mode of action studies, and in vivo efficacy assessment in preclinical mouse models of malaria.
Magnetic slowdown of topological edge states
Authors: Bal Guillaume , Becker Simon , Drouot Alexis
Published: September 2023

We study the propagation of wavepackets along curved interfaces between topological, magnetic materials. Our Hamiltonian is a massive Dirac operator with a magnetic potential. We construct semiclassical wavepackets propagating along the curved interface as adiabatic modulations of straight edge states under constant magnetic fields. While in the magnetic‐free case, the wavepackets propagate coherently at speed one, here they experience slowdown, dispersion, and Aharonov–Bohm effects. Several numerical simulations illustrate our results.
Real‐World Progression‐Free Survival as an Endpoint in Lung Cancer: Replicating Atezolizumab and Docetaxel Arms of the OAK Trial Using Real‐World Data
Authors: Mhatre Shivani K. , Machado Robson J. M. , Ton Thanh G. N. , Trinh Huong , Mazieres Julien , Rittmeyer Achim , Bretscher Michael T.
Published: September 2023

Evaluating cancer treatments in real‐world data (RWD) requires informative endpoints. This study replicated the atezolizumab and docetaxel arms of the OAK trial using RWD and compared progression‐free survival (PFS) outcomes derived from abstracted physician's notes in RWD (rwPFS) against PFS outcomes derived from the clinical trial PFS (ctPFS). Atezolizumab and docetaxel arms of the phase III OAK randomized controlled trial (RCT; NCT02008227) were replicated in a US nationwide real‐world database using selected OAK inclusion/exclusion criteria and propensity score‐based adjustment for baseline prognostic variables. Concordance of outcomes was assessed using Kaplan–Meier medians and hazard ratios (HRs). The RWD cohorts comprised 133 patients on atezolizumab and 479 patients on docetaxel. After adjustment, prognostic variables were balanced between RCT arms and corresponding RWD cohorts. The rwPFS and ctPFS outcomes showed better concordance for docetaxel (2.99 vs. 3.52 months; HR: 0.99, 95% confidence interval (CI): 0.85–1.15) than for atezolizumab (3.71 vs. 2.76 months; HR: 0.8, 95% CI: 0.61–1.02). Excluding events labeled “pseudo‐progression” from both RWD and RCT improved concordance for atezolizumab (4.24 vs. 4.14 months; HR: 0.95, 95% CI: 0.70–1.25). These findings were robust across sensitivity analyses. Replicating RCTs using RWD and comparing outcomes can help characterize RWD endpoints. Similarity of results between rwPFS and ctPFS at the cohort level may depend on drug category, highlighting the need for further studies to verify and understand when the corresponding outcomes can be compared, including within the same patient.
Early career primary teachers' curriculum‐making experiences: Enablers and constraints to knowledge‐led forms of curriculum‐making
Authors: Poulton Phillip , Mockler Nicole
Published: September 2023

With global trends focussed on standardisation of curriculum and increased teacher accountability, it has become commonplace for curriculum to be viewed simplistically as a product. While all teachers engage in forms of classroom curriculum‐making, questions remain as to what this looks like within an educational landscape that continues to portray teaching as a purely technical activity. This paper explores two Australian early career primary teachers' experiences of curriculum‐making, drawing attention to the enabling and constraining conditions which shape such experiences. We consider the impact of these enabled and constrained experiences on early career teachers' aspirations and ongoing development as knowledge‐led curriculum‐makers. We contend that such constrained experiences limit opportunities for early career teachers to develop professional identities as knowledge‐led curriculum‐makers and continue to reinforce unhelpful representations of teachers as ‘technicians’.
A comparison of digestive strategies for fishes with different feeding habits: Digestive enzyme activities, intestinal morphology, and gut microbiota
Authors: Jiao Fang , Zhang Lei , Limbu Samwel Mchele , Yin Hong , Xie Yuqing , Yang Zihan , Shang Zongmin , Kong Lingfu , Rong Hua
Published: September 2023

Fish feeding habit determines the digestive tract structure and intestinal microflora. However, the relationship between feeding habit, digestive intestinal morphology, and microbial diversity of omnivorous, herbivorous, plankton feeder, and carnivorous fish from the same environment has not been compared. This study compared the digestive enzyme activities, intestinal morphology, and intestinal microflora of omnivorous (Carassius auratus), herbivorous (Ctenopharyngodon idellus), carnivorous (Siniperca chuatsi), and plankton feeder (Schizothorax grahami) fishes and predicted the potential functions of specific microflora on different nutrients. Twelve intestine samples were collected from each of the four fishes from Dianchi Lake. The composition and diversity of microbial communities were determined by using high‐throughput sequencing of 16S rDNA. The results showed that the carnivorous fish (S. chuatsi) had higher trypsin and pancrelipase activities in the hepatopancreas and enteropeptidase in the intestine, but lower amylase activities in the intestine. The carnivorous fish intestine had more microvilli branches and complex structures than other fish species in the order carnivorous > herbivorous > plankton feeder > omnivorous. The intestinal microflora diversity was higher in the omnivorous fish and followed the order omnivorous > herbivorous > plankton feeder > carnivorous. Acinetobacter species and Bacteroides species were the most dominant flora in the carnivorous and herbivorous fishes, respectively. Acinetobacter species and Pseudomonas species might help the host to digest protein, while Bacteroidetes species may help the host to digest cellulose. Taken together, feeding habit determines the digestive enzyme activities, intestinal tissue morphology, and differential colonization of fish intestinal flora. The knowledge obtained is useful in feed formulation and feeding practices for the studied fish species.
Genetic structure shows the presence of small‐scale management units in a relict tree species
Authors: Li Yuan‐Yuan , Cui Min‐Yan , Le Xiao‐Wei , Gong Jun , Jiang Kai , Tong Xin , Zhang Qian , Li Jia‐Hui , Li Hong‐Yue , Lu Ling , Zou Jie , Wang Rong , Chen Xiao‐Yong
Published: September 2023

Identifying conservation units is crucial for the effective conservation of threatened species. Previous cases are almost exclusively based on large‐scale but coarse sampling for genetic structure analyses. Significant genetic structure can occur within a small range, and thus multiple conservation units may exist in narrowly distributed plants. However, small‐scale genetic structure is often overlooked in conservation planning especially for wind‐pollinated and wind‐dispersed trees, largely due to the absence of dense and elaborate sampling. In this study, we focused on a representative endangered relict plant,Metasequoia glyptostroboides. Using both nuclear microsatellites (nSSRs) and chloroplast DNA (cpDNA) fragments, we sampled across the narrow distribution range of this species and determined its conservation units by exploring its genetic structure and historical demography. cpDNA haplotypes were classified into two groups, but mixed in space, suggesting that the existent wild trees ofM. glyptostroboidescannot be divided into different evolutionarily significant units. However, using nSSRs, we detected strong spatial genetic structure, with significant genetic differentiation and weak gene flow between the samples in the east of the species' distribution range and other samples. The divergence between the two nSSR groups was dated to the Last Glacial Maximum (c. 19.6 kya), suggesting that such spatial genetic structure has been maintained for a long term. Therefore, these two nSSR groups should be considered as different conservation units, that is, management units, to protect intergroup genetic variations, which is likely to be the outputs of local adaptation. Our findings highlight the necessity to reveal small‐scale genetic structure and population demography to improve the conservation strategies of evolutionary potential of endangered plants.