bluuebunny/crossref_metadata_2025 huggingface dataset:
Swift‐Constructed Demountable Blind Bolt for Fast Execution and Disassembling of SHS Connection
Authors: Han Xiao‐Zhou , Chan Tak‐Ming
Published: September 2023

In the past decades, blind bolts were developed for structural hollow section (SHS) connection, and various types of blind bolt products have been commercially available. Nevertheless, some of the existing blind bolts cannot be easily demounted without the need of machine cutting after installation. Even if some blind bolts can achieve demountable function for structure by leaving some components inside the tube during the removal process, their installation and removal speed probably require to be raised further, or their mechanical performances may need to improve further for wider application. Therefore, it is worthy to develop a demountable blind bolt that has better mechanical performance, as well as can be installed and demounted easily and fast. In this study, the swift‐constructed demountable blind bolt is proposed. Design details, installation and removal process, material selection, heat treatment selection, relevant material examinations, and fabrication method are introduced accordingly. Experimental investigation is conducted to validate the proposed objective of this proposed bolt. Test results reveal that this proposed bolt has satisfactory mechanical performance, and the improvement of bolt tensile strength compared with the existing product can be achieved appropriately.
Comparison between numerical models for unbraced multiple bay pallet racks
Authors: Bové Oriol , Casafont Miquel , Bonada Jordi , López‐Almansa Francesc
Published: September 2023

Unbraced pallet racks are cold‐formed steel structures intended for the storage of products. They are subjected to severe lateral actions, and are particularly instability prone in the down aisle direction. Therefore, their design is compromised and needs of an accurate modelling. In current design practice, models using simplified beam formulations are regularly considered (such as Euler‐Bernoulli or Timoshenko), being them not able to reproduce torsional warping, or cross‐sectional distortion; these phenomena are accounted for indirectly via reduced sectional properties, and in the post‐process. This paper presents a comparison between three single column models, intended for the modelling of racks with a significant number of bays. Three models are presented: –Two 2D beam models using gross and equivalent section properties –A 3D beam model using equivalent section properties. Additionally, the results of these analyses are compared with those of a 3D model using shells and beams, presented in a previous research paper. Two rack configurations with different level heights are considered. The aim of this study is to capture the influence perforations of the uprights, warping, eccentricities and cross‐sectional distortion in the nonlinear response of racks subject to severe lateral actions.
Reliability Assessment of Eurocode 3 Design Rules for the Minor‐Axis Buckling of HSS I‐section Columns
Authors: Filho José Osvaldo Ferreira , da Silva Luís Simões , Tankova Trayana , Carvalho Hermes
Published: September 2023

Since the main purpose of the codes is to provide satisfactory safety levels, the reassessment of the reliability of the current design rules considering the new structural steels, as high strength steels (HSS), is necessary. As the reliability directly depends on several variables, their influence should also be considered. This paper aims to evaluate the influence of the randomness of the geometry, material, initial geometrical imperfections and residual stresses on the minor‐axis flexural buckling resistance of S690 HSS welded I‐section columns and the reliability of the Eurocode 3 [1,2] stability design rules. Monte Carlo simulations were executed to obtain the ultimate resistance of simply‐supported compressive members with slenderness varying from 0.3 to 2.2. The basic variables were stochastically modeled using existing statistical distributions from the literature and each generated element was numerically analyzed by a general‐purpose finite element software. Finally, the influence of the randomness of the basic variables and the safety provided by FprEN1993‐1‐1 [2] is discussed.
Proposal for the approach of torsional restraint by sandwich panels under uplifting loads
Authors: Krieglstein Tim , Kühn Bertram , Naujoks Bernd
Published: September 2023

Sandwich panels are able to support their substructure against failure resulting from stability loss. Especially for the thin‐walled cross‐sections, practical spans can often only be realized by taking the stabilization into account. In mechanics, this stabilization can be described as a combination of shear field and torsional restraint. However, for the load combination of self‐weight and wind suction, the shear field is usually applied to the flange in tension, which means that only slight stabilization effects can be added to the system. In addition, there is no standardisation for the approach of a torsional restraint under uplifting loads. Recent investigations showed on the one hand that the reduction of the torsional restraint under uplifting loads given in the literature is correct, but on the other hand, they offer a specific quantification of the reduction. Thus, a qualified estimation of the applicable torsional restraint under uplifting loads, based on tests and calculations using the finite element method, is made possible on the basis of a well‐founded mechanical model. The scientific background to this as well as the mechanical model and a proposal for its application in construction practice are described below.
Simplified approaches for material characterization – an alternative for advanced fatigue design methods
Authors: Rauch Marion
Published: September 2023

Integral parts of the Sustainable Development Goals of the United Nations are to ensure a sustainable and robust infrastructure as well as affordable and clean energy. To satisfy these societal needs, wind energy plays a considerable role and an overall functionality of wind turbines is essential. Taking into account the current age of the installed onshore wind turbines in Germany, elongated service life and economic further operation are indispensable. The application of local concepts, such as the Two Stage Model, enables elongated service life by a detailed consideration of structural and fracture mechanics input parameters. For these advanced assessment methods, amongst others, material characterization is needed for a more accurate lifetime prediction. The required cyclic material properties are usually derived by time‐consuming incremental step tests. In this paper, simplified approaches for the cyclic material characterization, such as the easy‐to‐use Hardness Method, are presented as an alternative. The applicability of the Hardness Method is demonstrated by a proof‐of‐concept study for structural steels and butt welds to determine the cyclic material properties. The study proves the potential of the easy‐to‐use Hardness Method for local concepts, such as the Two Stage Model.
Structural response and design of stainless steel hollow section columns at elevated temperatures
Authors: Quan Chunyan , Kucukler Merih
Published: September 2023

This paper investigates the flexural buckling behaviour and design of stainless steel circular, elliptical, square and rectangular hollow section (CHS, EHS, SHS and RHS) columns at elevated temperatures through numerical modelling. Shell finite element models are utilised to perform numerical parametric studies whereby benchmark structural performance data are generated. A large number of cold‐formed and hot‐rolled austenitic, duplex and ferritic stainless steel CHS, EHS, SHS and RHS columns at elevated temperatures are taken into account, considering various cross‐section and member slendernesses. Since the fire design provisions provided in the European fire design standard EN 1993‐1‐2 for stainless steel columns are largely based on those originally developed for carbon steel columns, they typically lead to rather inaccurate ultimate resistance predictions for stainless steel columns at elevated temperatures. To address this, in the present study, a new flexural buckling design method for stainless steel hollow section columns at elevated temperatures is put forward. The accuracy, safety and reliability of the proposed design method and the provisions in EN 1993‐1‐2 are assessed. It is observed that the proposed fire design method leads to more accurate, safe‐sided and reliable flexural buckling resistance predictions for stainless steel hollow section columns at elevated temperatures relative to the provisions in EN 1993‐1‐2.
Influence of the geometry of butt welds and longitudinal attachments on their fatigue resistance
Authors: Hofmann Gloria , Kuhlmann Ulrike
Published: September 2023

Many constructions, such as wind turbines, bridges and crane runways, are cyclic loaded so that fatigue failure may occur. Therefore, in the course of the revision of Eurocode 3, two research projects funded by AiF‐DASt re‐investigate the classification of constructional details of EN 1993‐1‐9. This paper focuses on the geometrical influence on the fatigue resistance of butt welds and longitudinal attachments. First, the influence of the plate thickness on butt welds was investigated. Both a meta‐study based on test results of various research projects and our own test series on butt welds up to 80 mm thickness led to interesting conclusions.

Furthermore, the influence of the length and radius of longitudinal attachments on the fatigue resistance was investigated. By experiments and numerical analysis, clarification has been sought whether the transition radius larger than 150 mm or the ground weld toe is decisive for the improvement of the fatigue resistance. Since previous meta‐studies could not provide a clear result on the influence of the longitudinal attachment length, this was also investigated.

A database established in the projects allows to integrate and assess the specified details of butt welds and longitudinal attachments in the context of the overall approach in EN 1993‐1‐9.
Fatigue Verification Concept for Details containing Weld Imperfections
Authors: Bartsch Helen , Feldmann Markus
Published: September 2023

Steel structures subjected to repeated stress variations must be verified against fatigue in accordance with EN 1993‐1‐9 on the basis of a detail catalog. As one major concern, the background of the detail classification in terms of an extensive database does not provide information on the considered quality of welds. Certain weld imperfections are present in every construction. However, the extent of imperfection sizes that can be tolerated to provide sufficient fatigue resistance has not yet been scientifically determined.

On an experimental and numerical basis, the presented concept allows the quantitative connection of fatigue classes with sizes of weld imperfections. For the two representative details of the load‐carrying‐cruciform joint and the non‐load‐carrying transverse stiffener, basic fatigue classes without explicit imperfections are calculated first. Furthermore, stress increase factors were determined that indicate the decrease in fatigue strength for weld imperfections of different type and size.

A combination model is used to determine the fatigue strength of a detail with multiple weld imperfections. Using a simple formula and reading fatigue classes and reduction factors in tables, the fatigue strength of an imperfect detail can be easily determined.
Bracing requirements for a semi‐rigidly connected column considering column lateral stiffness and initial curvature
Authors: Zhang Linbo , Xu Lei
Published: September 2023

This paper theoretically assesses the required brace stiffness and strength for a semi‐rigidly connected column with a lateral brace at the mid‐height, by introducing a half‐length column model and adopting the concept of storey‐based buckling. Unlike that in Winter's model, column lateral stiffness and initial curvature associated with column initial out‐of‐straightness are accounted for. A coefficient, which is a function of applied load and column end connection stiffness, is introduced to characterize the effect of column initial curvature on bracing requirements. By comparing the results obtained from the analytical method and current structural steel and cold‐formed steel design standards, it has been found that the required brace strength stipulated in these standards are generally conservative in various degrees for design loads; however, the required brace stiffness should be increased if the effect of column initial curvature is considered. The results obtained from the proposed approach are verified against the finite element analysis, indicating that the proposed approach provides an accurate evaluation of required brace strengths for semi‐rigid columns and is recommended to be adopted for engineering practice.
Experimental Study on the Local Buckling Response of WAAM Stainless Steel Square Hollow Sections
Authors: Evans Siân , Xu Fangda , Wang Jie
Published: September 2023

Wire Arc Additive Manufacturing (WAAM) has the potential to produce free form metallic structures, suitable for use in the construction industry, and so is currently being rapidly developed by structural engineers. This paper details an experimental program investigating the stability performance of ten WAAM 316L stainless steel square hollow section stub columns with varying cross‐sectional slenderness. Tensile coupon tests were also carried out to determine the material properties of the WAAM builds in three different directions relative to the printing direction. The tensile coupon tests revealed a high degree of anisotropy while the ductility requirements set out by Eurocode 3 are met by all coupons. Two different thickness parameters (i.e. average thickness and average minimum thickness) were obtained through geometric analysis of the stub columns, and are used in conjunction with Eurocode 3 design rules for conventional stainless steels. The predictions to the load‐carrying capacities offered by these two design treatments were compared with the stub column test results, confirming the applicability of the current Eurocode 3 design rule, along with recommended design treatments.
Structural behavior of single‐sided welded HSS‐T‐joints with softening in the heat‐affected zone
Authors: Rust Brian , Kästner Thoralf , Stroetmann Richard
Published: September 2023

In the case of high‐strength steels, softening in the heat‐affected zone (HAZ) is possible due to the heat input during the welding process. Therefore, in addition to weld failure, other forms of failure of the welded joint cannot be excluded. Within the framework of the AiF‐FOSTA research project P1453, experimental investigations are carried out on single‐sided welded T‐joints. The aim of the investigations is to analyze the failure modes resulting from softening in the HAZ. Specimens with different weld types, steel grades, plate thicknesses and cooling times t8/5 are investigated. The softening of the HAZ is experimentally evaluated for thermome‐chanical rolled and quenched and tempered high‐strength steels with yield strengths from 500 to 960 MPa by thermo‐physical forming simulations. The results will be used to improve the design rules for welded joints. In particular, this includes a consideration of the heat‐affected zone in the design of welded joints made of high‐strength steels. The paper presents the results of thermo‐physical forming simulations. By measuring macrosections of butt joints, a description of the expansion of the heat‐affected zone as a function of peak temperature and cooling time is presented. Furthermore, results of structural mechanics studies for the load bearing capacity analysis of single‐sided welded T‐joints are presented. This is followed by a detailed description of the experimental test program.
Imperfections in realistic metal wind turbine support towers: a one‐at‐a‐time (OAAT) study
Authors: Kathirkamanathan Lijithan , Sadowski Adam , Seidel Marc
Published: September 2023

The ultimate limit state of buckling is an important consideration for the design of wind turbine support towers (WTSTs) which is increasingly being done with the aid of advanced nonlinear finite element analysis according to EN 1993‐1‐6. As these towers are relatively slender thin‐walled metal shell structures, their response and buckling resistance is invariably affected by geometric imperfections. This paper presents a sensitivity study into the possible relative influences of four different types of realistic imperfections that are likely to arise in WTST construction on the elastic‐plastic buckling resistance as assessed by computational GMNIAs. These include idealised but realistic representations of axisymmetric circumferential weld depressions, unintended eccentricities at curved plate boundaries, a global out‐of‐roundness and corrected parallel flange interface gaps. The relative sensitivity is explored via a ‘one‐at‐a‐time’ (OAAT) study where all factors but one are kept at a constant intensity while the active factor is scaled, with the influence on the computed GMNIA under two load cases recorded. The OAAT study suggests that for shell structures representative of the geometric ranges typical for WTSTs, the weld depression has the most deleterious effect on the predicted buckling resistance.
Effects of Deposition Rate on Local Stability of Wire Arc Additively Manufactured Outstand Elements
Authors: Evans Siân , Hadjipantelis Nicolas , Wang Jie
Published: September 2023

A great focus is currently being placed on the development of applications of Wire Arc Additive Manufacturing (WAAM) in structural engineering. To facilitate this development, an experimental programme investigating the effects of the deposition rate on WAAM 316LSi stainless steel outstand elements has been conducted. Equal angle section (EAS) stub columns with four different cross‐sectional slendernesses were produced using WAAM. For each slenderness, four different deposition rates were employed; hence, overall, sixteen EAS stub columns were produced, 3D scanned and tested to examine their local stability. To keep the heat input constant between all cases, for each deposition rate, the travel speed was varied accordingly. Alongside the EAS specimens, tensile coupon testing was conducted to determine the material properties corresponding to each deposition rate. The tensile coupons were extracted at three different orientations (0°, 45° and 90°) relative to the deposition direction in order to investigate the degree of material anisotropy. In the present paper, following the description of the EAS stub column test results, the applicability of current Eurocode design rules and the Continuous Strength Method for the prediction of their design strength is assessed.
A MATLAB finite element toolbox for the efficient nonlinear analysis of axisymmetric shells
Authors: Filippidis Achilleas , Sadowski Adam J.
Published: September 2023

Shells of revolution under axisymmetric conditions exhibit a circumferentially uniform pre‐buckling stress state and are important fundamental systems which often serve as reference systems for those under more complex conditions. Given this status, work is continuing on a careful and complete characterization of their buckling response with the aid of the Reference Resistance Design (RRD) framework for the ultimate benefit of the EN 1993‐1‐6 Eurocode on the strength of stability of metal shells. The situation is greatly complicated by the fact that while modern finite element software packages offer axisymmetric shell elements in an efficient 2D modelling plane, these are not capable of detecting bifurcation buckling into non‐axisymmetric modes which are often critical for slender systems. Reverting to a full 3D plane is possible, but grossly inefficient and the explicitly modelled circumferential direction is parasitic and detrimental to the overall solution quality. AQUINAS is an accessible and intuitive toolbox developed by the Authors in MATLAB for the efficient analysis of axisymmetric shell structures, aiming to reintroduce a modelling capability that was once standard in the field. Data input is entirely object‐oriented and matrix assembly is parallelized with pre‐compiled C++ routines, with users being able to take direct advantage of MATLAB's visualization properties. The software natively supports the LA, LBA, MNA, GMNIA etc. Eurocode analysis taxonomy. This paper demonstrates the current capabilities of the toolbox, describes the extensive programme of verification against existing established solutions that has been performed, and illustrates its ability to efficiently compute very detailed capacity curves using the EN 1993‐1‐6 capacity curve framework.
Lateral‐torsional buckling of beams made of mono‐symmetrical thin‐walled sections
Authors: Vermeylen Maxime , Bezas Marios‐Zois , Crispin Mathieu , Jaspart Jean‐Pierre , Demonceau Jean‐François
Published: September 2023

Thin‐walled cold‐formed sections are extensively used as primary structural elements in storage system structures or steel houses, or as secondary elements like roof and wall systems, floor girders, etc. Despite their many advantages, such as transportability and lightweight, these members are usually susceptible to lateral‐torsional buckling as they are not always laterally restrained.

This paper deals with the elastic stability of such beams and, in particular, is focusing on cross‐sections that are symmetrical about their major axis only, like channel or sigma profiles, and loaded perpendicular to their axis of symmetry. Their stability has been studied analytically, in accordance to available provisions in the concerned codes, and numerically with two different finite element tools.
Evaluation of Design Codes for Hot‐Rolled Steel Angles in Concentric and Eccentric Compression
Authors: Gomes José , Carvalho Hermes , da Silva Luís Simões , Ferreira Filho José Osvaldo , Lavall Armando
Published: September 2023

Hot‐rolled steel angles are utilized in various construction systems. This work presents an extensive numerical study on the behavior of hot‐rolled steel angles under concentric and eccentric compression. The numerical results were used for the evaluation of existing design procedures commonly applied in practice. In general, the analytical rules were on safe‐side in most analyzed cases. But in case of angle members in eccentric compression by two bolts, the codes presented very high values for ultimate compressive load capacity. Finally, the study extended the numerical data on the resistance available in the literature and promoted a critical discussion about the ongoing revision of design rules for angles concentrically and eccentrically loaded in compression.
I‐beam‐to‐SHS‐column moment resisting joints using passing‐through plates under equal bendings
Authors: MADHOUNI Mouad , COUCHAUX Maël , HJIAJ Mohammed , KANYILMAZ Alper
Published: September 2023

Conventional I‐beam‐to‐SHS‐column moment resisting connections are generally stiffened with external diaphragms in order to limit excessive deformation of the tube‐wall. Passing through plates welded to the tube is an alternative solution that can develop significant strength and stiffness. This solution has been applied to CHS column and initial findings from RFCS project LASTEICON were encouraging. RHS columns are also widely used in practice due to simplicity of connections manufacturing. The new RFCS project LASTTS aims to investigate the application of this technique of passing through plates to SHS columns using laser cutting technology.

The objective of this paper is to present the behaviour of I‐beam‐to‐SHS column moment resisting joints using passing‐through plates under equal hogging bending moments. A finite element model using brick elements is firstly presented. This model is used to perform a sensitivity analysis varying passing through plates thicknesses as well as SHS column dimensions. The failure mode is caused by the flange plate buckling inside the tube. Analytical models are developed to determine the bending resistance and initial rotational stiffness of these connections.
Experimental investigations of residual stresses in thick high‐strength steel plates
Authors: Schäfers Michael , Müller Eckehard , Mensinger Martin
Published: September 2023

Residual stresses strongly influence the load‐bearing capacity of steel members under compressive axial loads. Current developments in steel and steel‐concrete composite structures imply the use of high‐strength steel grades up to 960 MPa. For such steel plates, only limited results of residual stress investigations are known so far. The authors have applied two established measuring methodologies like the sectioning method and X‐ray diffraction to determine the residual stress state of 40 mm thick steel plates and different widths. The results show that the distribution and amount of longitudinal residual stresses are mainly determined by the oxyfuel‐cutting procedure used to manufacture the specimens. The distribution over the thickness could be determined by X‐ray diffraction. Compared to the results of examinations on lower‐grade steel plates an assumed correlation of residual stresses and steel grades could not be observed. Consequently, residual stresses have a reduced influence on the load‐bearing capacities of structures prone to buckling as the ratio of yield strength to residual stress states declines significantly.
I‐beam‐to‐SHS column moment resisting joints using passing‐through plates under opposite bending moments: numerical and analytical studies
Authors: MADHOUNI Mouad , COUCHAUX Maël , HJIAJ Mohammed , KANYILMAZ Alper
Published: September 2023

As thin walled HSS columns are very flexible, they usually exhibit excessive deformation when resisting a bending moment or transverse loads. Adding exterior/interior diaphragms is one way to remedy the problem. Another option that can significantly increase strength and stiffness is to allow passing plates through the hollow column by means of Laser Cutting Technology (LCT). This solution was tested on CHS columns within the RFCS LASTEICON project. The first outcomes were promising. One of LASTTS new RFCS project's overarching concerns is to enlarge the range of application of the passing‐through solution onto SHS columns.

The goal of this research paper is to present the behaviour of I‐beam‐to‐SHS column moment resisting joints using passing‐through plates under opposite bending moments. First, a solid‐based finite element model is presented. This model is used to conduct a sensitivity analysis with different SHS column and passing plates geometry. The failure mode is resulting contribution of both weld/tube‐wall tearing in tension, and chord face crushing in compression. Analytical models are developed in an attempt to ascertain the bending resistance and initial rotational stiffness of this new type of connections.
Measures to Improve Seismic Resistance by Fuse Mechanism in Pier Structures
Authors: Sekiguchi Minoru , Taniguchi Nozomu , Kobayashi Kaoru
Published: September 2023

In Japan, temporary pier structures are designed to withstand earthquakes in consideration of their short service life, and seismic inputs exceeding the design are also expected. In order to confirm the deformation behavior of the fuse mechanism in this temporary pier structure, a fundamental study was conducted using a model specimen. The strength test results showed that the fuse mechanism behaved similar to a rigid body, and then the mortar fuse failed. After the failure of the mortar fuse, the reaction force was generated by the addition of the residual bearing capacity of the mortar fuse and the reaction force of the coil spring. The dynamic loading test results showed that the CFT columns contacted the remaining portion of the fuse after the mortar fuse ruptured, temporarily increasing the maximum response acceleration to 35 m/s2, but the response period became longer, indicating the deformation behavior of the fuse mechanism. In addition, the maximum load of the mortar fuse mechanism and the natural period after the mortar fuse rupture were calculated from the design values of the mortar fuse strength and the spring constant of the coil spring.
Potentials of reusing steel skeleton structures from multistorey parking units for architectural applications
Authors: Manot Hilke , Lienhard Julian
Published: September 2023

In the context of urban mining, which aims to extend the value chain of building components to conserve resources, save energy, avoid waste, and reduce emissions, the reuse of structural steel has great potential, that has hardly been exploited to date.

In Germany, a significant amount of steel is found within multistorey parking units. Due to the standardised and mass relevant steel used in these structures and considering their diminishing significance in the context of transportation transitions, these buildings offer specific opportunities for reuse.

The research aims to investigate the reuse of structural steel from parking facilities in a new architectural design purpose with focus on multistorey residential buildings, as these will become increasingly important in the future construction due to the predicted growth of the world population and global cities.

The research methodology begins by identifying the reuse potential of structural steel from parking units for future multi‐storey residential buildings. The study then delves into the exploration of hybrid construction methods, which involve incorporating standardized steel profiles with clay and reinterpreting historical cap ceilings. These approaches aim to foster the development of innovative architectural solutions.
Stress range in the welded cruciform joint in the shell model using the Hot Spot Stress Method
Authors: Golubiatnikov Kirill , Wald František
Published: September 2023

This paper focuses on the linear extrapolation procedure for the Hot Spot Stress Method on a platés surface using shell models. Published papers have shown the benefits of solving the fatigue life by methodologies that integrate changes of the stress near the weld toe. This procedure is based on modelling the joints by solid elements. Current advanced connection models for steel structures are based on shell models which save computational time by an order of magnitude and allow the modelling of structural joints in a sufficiently short time using second‐order theory.

Seven models for making shell welded connections are presented here, each of which was prepared for a specific joint. Many researchers have reported that non‐universality and deviations of the stress peak value in the first extrapolation point are major questions. A sensitivity study has indicated that there is a conditional stable ratio between the values of the stress ranges in the two evaluation points. A comparison between cases, that use experimental parameters and results taken from the literature, has shown that there is a reduction in the differences of the stress ranges between solid and shell models.
Investigations of the shear connectors and the load‐bearing behaviour of steel cross‐laminated timber composite beams
Authors: Böhm Noah , Vogelsberg Achim , Kühn Bertram
Published: September 2023

A strengthening of cross laminated timber (CLT) by a composite effect with steel girders can act as a sustainable option to replace concrete or composite slabs for spans of more than 7 m. The efficiency of a composite structure is strongly influenced by the stiffness of the shear connectors. Therefore, fully threaded screws and shear studs were investigated in double push‐out tests. The screws are inclined to increase their stiffness and are rotated within the drilled hole towards the web, so that a multidimensional load situation with both axial and shear loads results. The shear studs are placed in openings of the CLT and cast in with mortar. The shear tests confirmed that their load bearing behaviour can basically be described with existing analytical calculation approaches. The findings were extended in large‐scale 4‐point bending tests to investigate the bending behaviour of the composite beam.
High‐Performance Pre‐engineered Steel‐Concrete Composite Beams for Sustainable Construction – Mechanical Behaviour of the Full‐Scale Beams
Authors: Zhao Ming‐Shan , Chua Guan‐Feng , Ding Miao , Chiew Sing‐Ping , Yang Yi , Cong Zhengxia , Ng Yiaw‐Heong
Published: September 2023

This paper presents an experimental study on the behaviour of high‐performance pre‐engineered steel‐concrete composite beams. The slab is constructed with green concrete of grade C55/67 made using recycled concrete aggregates to replace 20% of natural aggregates, and GGBS together with silica fume as supplementary ce‐mentitious materials to replace 25% of the Ordinary Portland Cement (OPC). Pre‐engineered (built‐up) structural steel asymmetric section of grade S460M is adopted for optimised structural efficiency. To verify the compatibility among the three different materials used, i.e., the S460M structural steel, green C55/67 concrete, and the shear studs, shear connection specimens were designed and tested with reference made to EC4. Subsequently, 2 full scale steel concrete composite beams are tested until failure. The results showed that the EC4 design equations for predicting the shear resistance and the bending moment resistance are still conservative for the materials and full‐scale beams.
Specific distortion‐induced fatigue failure at main girders of a railway bridge – efficiency of different reinforcements based on strain measurements
Authors: Unterweger Harald , Derler Christoph
Published: September 2023

At the main girders of a three span continuous girder railway bridge, built in the 1960s, through‐thickness cracks were detected in the web, at the location of the transverse stiffener to main girder connections. The transverse stiffeners are not welded to the girder flange, in order to increase their fatigue resistance. Instead, fitting strips between the stiffeners and the bottom flanges were used.

First of all, the paper presents the results of local strain measurements at the original detail, without any reinforcement, for individual train passages. These results confirm a distortion‐induced fatigue failure, due to an unexpected high‐frequency oscillation of the web plate. Based on that, three different types of reinforcement were developed and installed at the bridge. For each type of reinforcement further strain measurements were done during regular train service. Also, a weigh‐in‐motion‐system was installed, to specify a representative passenger and freight train each. From the local strain measurements, during the passage of these two trains, the stress‐spectra were evaluated for all three types of reinforcement. Furthermore, existing fatigue test data of a similar connection detail from the literature were reassessed in order to provide an accurate fatigue resistance for the damage accumulation. The comparison of the evaluated fatigue damage of these individual stress spectra indicates the efficiency of each type of reinforcement.

Finally, also representative reduction factors of the initial stress ranges without reinforcement, were developed for each type of reinforcement. This allows a more generalized assessment, regarding the efficiency of the different types of reinforcement, not just valid for individual trains but also for the whole train traffic.
Behaviour of demountable steel‐concrete composite beams with bolts and headed studs
Authors: Jakovljević Isidora , Spremić Milan , Fric Nenad , Marković Zlatko
Published: September 2023

Implementation of demountable beams in steel‐concrete composite floors enables structure reuse during several life cycles, consequently leading to savings in material consumption and reduction of emissions, providing overall ecological benefits. The behaviour of the innovative demountable beam with a shear connection consisting of headed studs and bolts is analysed in this paper. The proposed beam is formed of a steel profile and a steel‐concrete composite slab cast in open trough profiled steel sheeting. Headed studs, welded to the additional steel angles, are placed in sheeting ribs, whereas bolts are installed between ribs, connecting the steel angles and profile flange. A numerical FE model of a full‐scale steel‐concrete composite beam has been developed to analyse the beam behaviour under service loads. Experimental results of push‐out tests have been used to describe the load‐slip behaviour of headed studs, whereas bolt response has been simulated according to the experimental investigations of lap joints with preloaded bolts and oversize holes. The parametric study has been conducted by varying the bolt diameter, grade and bolt hole size. The results have validated the applicability of the proposed system, confirming the fulfilment of serviceability limit state requirements.
Deformation behaviour of high‐strength steel welds using DIC
Authors: Ghimire Abhishek , Wald František
Published: September 2023

This paper focuses on the deformation and strength behaviour of high‐strength steel (HSS) transverse fillet welds. The behaviour of six lap‐welded fillet joints made of high‐strength steels (HSSs) is investigated under tension load through experiment. Due to some weaknesses in the deformation measurement using traditional techniques, the digital image correlation technique (DIC) is used to measure the deformation of transverse fillet weld connections. The development of the deformation on the specimen throughout the loading process was analysed using DIC measurement. The deformation of transverse fillet lap‐welded connections from HSS is always less than 1 mm. The strength calculated from the weld's fracture surface area shows better results than the theoretical weld area because it provides the real strength of the weld. In most cases, the weld failure did not occur along the throat section. Moreover, it is confirmed that the analytical models offered by prEN 1993‐1‐8:2020 are conservative for all the specimens.
Effects of section slenderness and concrete strength on the cross‐sectional behaviour of lightweight concrete‐filled cold‐formed built‐up box sections
Authors: Teoh Keat Bin , Chua Yie Sue
Published: September 2023

This paper concerns axial compressive behaviour of lightweight concrete‐filled cold‐formed built‐up box sections (CFBBS) at cross‐sectional level. A total of twenty‐four lightweight concrete‐filled CFBBS stub columns and their hollow counterparts—formed by nesting two asymmetric lipped channel sections front‐to‐front—were tested. The varying parameters in the present experimental study included three cross‐section slenderness (h/t) ranging from 75 to 125 and three concrete grades (fc) with measured cylinder strengths varying from 33.5 to 55.6 MPa. The typical mechanical behaviour of the stub column tests was discussed in terms of load‐end shortening response. The parametric influences on the load‐end shortening response and ultimate compressive load were scrutinised.
Material characterisation tests of ultra‐high‐strength steels S960QL and S1100M under natural fire conditions
Authors: Uszball Sara , Knobloch Markus
Published: September 2023

Fire hazards represent one of the most important threats to the built environment with serious economic consequences for society and most dangerous threats to life. Fire engineering is the key discipline to improve fire safety in the building environment in a cost‐effective manner. Comprehensive knowledge of the material behavior is the basis for a thorough understanding and a realistic modeling of the structural fire behavior of steel structures. For state‐of‐the‐art buildings with increasing requirements, the utilization of high‐strength steels is favorable, as they can contribute to resource and energy efficiency due to their good strength‐to‐weight ratio. Modern production processes enable the production of structural steels with very high nominal yield strengths. For those ultra‐high‐strength steels there are currently no experimental results available regarding the material behavior in case of fire and the post fire residual strengths. The paper provides experimental data of the first test program regarding the constitutive material behavior of ultra‐high‐strength steels of grades S960QL and S1100M in the case of fire, taking into account the entire fire progress including the heating and cooling phases and the post fire range.
Out‐of‐plane flexural buckling design resistance of welded I‐members made of flame‐cut flanges
Authors: Lebastard Maxime , Couchaux Maël , Bureau Alain , Hjiaj Mohammed
Published: September 2023

In practice, welded I‐members of steel buildings are usually made of flanges that are either wide hot‐rolled plates, or plates longitudinally divided using flame‐cuts. The residual stresses distributions resulting from both types of fabrication process are substantially different. However, the Eurocode 3 buckling design resistance of a welded I‐member in compression assumes hot‐rolled flanges, thus neglecting the beneficial impact of flame‐cuts. A parametric study is then performed regarding the out‐of‐plane flexural buckling of welded members made of flame‐cut flanges. 377 doubly symmetric members either with a uniform or a tapered cross‐section are studied. These numerical results are firstly employed to evaluate the safety and accuracy of the Eurocode 3 rules for such members by computing partial factors. The current rules proving overly conservative, two proposals are made for welded columns made of flame‐cut flanges. A first simple proposal suggests a more favorable buckling curve. A second proposal introduces an imperfection factor depending on the cross‐sectional height‐to‐width ratio. Partial factors computed for both proposals are satisfactory, the second proposal being more precise.
Bending resistance of steel‐timber composite (STC) beams: analytical vs. numerical investigations
Authors: Romero Alfredo , Yang Jie , Odenbreit Christoph
Published: September 2023

This contribution presents the results of analytical and numerical investigations of the ultimate bending resistance of simply supported steel‐timber composite beams with uniformly distributed load, they consist of three main components: (i) the laminated veneer lumber (LVL) slab, (ii) the downstand steel beam (IPE‐profile) connected by means of (iii) demountable shear connectors, which allow for deconstruction and circular reuse of the steel beam as well as the timber slab element. The mechanical properties of the cross‐banded LVL as well as the load‐slip curves of demountable shear connectors, which have been obtained experimentally, were implemented in both the analytical and numerical models. In this paper both solutions have been compared, first the ultimate bending resistance was calculated analytically through a strain‐controlled approach with various degrees of shear connection. Then, numerical simulations were conducted in the finite element software ABAQUS to determine the ultimate bending capacity and the load‐deformation behaviour. Finally, the results of both approaches are presented and compared.
Directly Reusable Steel Column Base Connection ‐ Concept and Numerical investigation
Authors: JEYABALAN Aswin Kumar , SELVARAJ Sivaganesh , CHAN Tak‐Ming
Published: September 2023

Construction industry as a whole should transform into designs that enable demountability and direct reuse of structural elements to achieve the circularity in construction. Currently, structural connections enabling direct reuse of components in construction are limited. Column base connections are one of the main load transfer units of a steel structure for the magnitude of the forces being transferred from the superstructure. This paper presents an interlocking type of column base connection that enables direct reuse of all associated structural components. The proposed interlocking connection transfers the force through the plate bearing and holding mechanisms and requires minimal number of bolts. In addition to the direct reuse and better load transfer approach, the new interlocking connection enhances and simplifies the mounting procedure that leads to increased productivity in construction. This article discusses the overall concept of the proposed interlocking connection, design philosophy and compares the failure modes with existing conventional bolted column base connections for various loading cases through finite element analyses. Main parameters investigated are the effects of bearing length of connector element and connector element thickness under uniaxial loading. A finite element model of the proposed interlocking connection is built through which the influential parameters are analysed.
Buckling behavior of tubes subjected to combined bending and torsion
Authors: Ding Victoria , Ádány Sándor , Torabian Shahab , Pervizaj Anil , Schafer Benjamin W.
Published: September 2023

Wind turbine towers are highly slender and made of thin cylindrical shells with large diameter‐to‐thickness ratios, which means stability is an essential concern. The high diameter‐to‐thickness ratios of these cylinders make them highly imperfection sensitive, meaning their failure loads and failure modes are highly dependent on initial geometries. Combined bending and torsion is commonly a controlling load case in the upper tower segments, but this load case has not seen significant study to date. To address the knowledge gap, an experimental study was conducted on the stability of cylinders under combined bending and torsion. A total of 48 cylinders were tested with varying diameter‐to‐thickness ratios and bending‐to‐torsion combinations seen in wind turbine towers. To better understand how imperfections affect the buckling modes of these thin‐walled cylinders, a 3D laser scanner was used to determine geometric imperfections of each test specimen prior to testing. This paper details the test setup and results of the experiments.
Fatigue behaviour of hybrid grouted joints under axial loading
Authors: Boretzki Jakob , Albiez Matthias , Damm Jannis , Ummenhofer Thomas
Published: September 2023

Steel constructions made of circular hollow sections are commonly joined by welding or ring‐flange bolting. An additional, novel joining method is the so‐called hybrid grouted joint. The hybrid grouted joint is characterised by its multi‐layered composition. In contrast to state‐of‐the‐art grouted joints, hybrid grouted joints include thin adhesive layers, which are applied on the steel surfaces prior to grouting. Sand grains are embedded in the yet uncured adhesive. After the curing of the adhesive, the surface has a high degree of roughness. This allows a high‐performance interlock between fine grain grout and the adhesively bonded sand granules across the contact surfaces in the overlap area. The ability to transfer loads across a wide area with low stress concentrations makes the hybrid grouted joint a promising joint alternative especially regarding the fatigue performance. This paper summarises the main findings concerning fatigue behaviour of the hybrid grouted joint under axial loading. Wöhler diagrams were determined in numerous fatigue tests for two combinations of adhesive and grout.