bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of adhesives in preloaded bolted connections for hot‐dip galvanised constructions
Authors: Mantik Justus , Glienke Ralf , Denkert Christian , Dörre Maik , Vallée Till , Fricke Holger , Henkel Knuth‐Michael
Published: September 2023

Fatigue loaded structures in steel construction, e. g. bridges and towers of wind turbines, are preferably executed with slip‐resistant connections since these connections are generally regarded as fatigue resistant. Nevertheless, the transferable shear loads are limited by the slip factor and the preload level in the bolts. With additionally applied adhesive on the friction surfaces, the so‐called preloaded hybrid connection is formed. The related increase in load capacity considering various manufacturing influences is presented in the following article.
Preliminary study of axial‐moment interaction diagrams for semi‐rigid end plate bolted connections
Authors: Gracia Javier , Gil Beatriz , Bayo Eduardo
Published: September 2023

This research deals with the axial‐bending interaction in bolted steel beam to column connections along the strong axis of the column. In order to define the interaction curves, firstly, a series of tests of doubly symmetric bolted connections were carried out in which two column sizes were considered, while the beam, end plate and bolts remained the same. These joints were tested under pure compression, as well as simultaneous bending and compression, and with different load levels. Afterwards, reduced finite element models including initial imperfections were made. These models are validated by means of the results obtained in the experimental program. The aim of the reduced model is to enlarge the range of studied loading combinations in terms of different percentages of axial load and bending moment. Finally, with the results obtained, a preliminary normalized interaction diagram for this type of joints was deduced.
Effect of Curling Phenomenon on Block Shear and Tear‐out Strengths of Bolted Connections
Authors: Pham Viet Binh , Pham Cao Hung , Hancock Gregory J
Published: September 2023

Block shear and tear‐out behaviours and strengths of cold‐formed steel bolted connections have been thoroughly investigated in the literature. Nevertheless, the curling phenomenon occurring in the thin plate which may affect the strength and behaviour of these failure modes in bolted connections between thin and thick plates has not been researched in detail. Therefore, the behaviour and block shear and tear‐out strengths of bolted connections undergoing the curling effect were investigated through a series of 48 tests at the University of Sydney. Various types of cold‐formed steel sheets (i.e., G300, G450, G500 and G550 to AS 1397) were used for the specimens to obtain a wide range of material properties. The cold‐formed steel sheets with thickness of 1.0 mm, 1.2 mm and 1.9 mm in conjunction with different edge distances as the main variables were studied to investigate the curling effect. On the basis of the experimental results, the observed curling phenomenon not only changed the behaviour but also affected the ultimate strength of the bolted connections. Comparison of the test results with the design specifications and standards from AISI S100:16 (R2020) w/S3‐22 and AS/NZS 4600:2018 demonstrate that the design equations overestimate the nominal shear strength without the consideration of curling. Consequently, a new design equation for the block shear and tear‐out strength considering the curling effect is proposed in this paper.
Influence of semi‐rigid joints on the seismic performance of single‐storey steel frames
Authors: Venneri Greta Agata , De Matteis Gianfranco , Brando Giuseppe
Published: September 2023

The design of joints of steel frames is often simplified, assuming that they have a fully rigid or ideally pinned behaviour. This wrong assumption is sometimes acquiesced by national technical codes, which mainly focus on the behaviour of simple connections and neglect the role of the joints in terms of global structural behaviour, particularly under lateral loads. In this paper, a numerical study about the evaluation of the influence of partial‐strength/semi‐rigid joints on the seismic performance of one‐storey steel buildings is presented. For this purpose, a population of real steel buildings has been considered, for which column bases and/or beam‐to‐column joints were originally designed as infinitely resistant/rigid restraints, but that, after the application of the component method, were found to be characterized by a partial‐strength/semi‐rigid behaviour. Finite element models of the examined buildings were developed, assuming both the theoretical and the actual joint behaviour. Fragility curves were constructed through nonlinear dynamic analyses, so to evaluate the seismic vulnerability of the structures and assess whether they need joint reinforcement, or, otherwise, if they already ensure adequate seismic safety.
Study on load‐carrying capacity of MAG butt‐welded mixed connections with different steel strengths
Authors: von Arnim Mareike , Eichler Stefan , Brätz Oliver , Hildebrand Jörg , Kuhlmann Ulrike , Bergmann Jean Pierre , Flügge Wilko
Published: September 2023

Mixed connections of normal‐strength steel and high‐strength steel can enable an optimum resource‐saving use of materials by adapting the material strength to the forces acting on them. But the design and calculation of butt‐welded mixed connections is not clearly regulated in the currently valid standards EN 1993‐1‐8 and EN 1993‐1‐12. In the research project Effective design concepts for mixed connections in steel structures an extensive experimental program with 180 mixed connections has been conducted to investigate the load‐carrying capacity and behaviour of these connections. The weld joint specimens were made with normal‐strength steel S355J2+N and different high‐strength steels S690QL, S700MC or S960QL. Varying parameters were also the filler metals, plate thicknesses, weld bevels and the heat input during welding. The influence of these parameters on the load‐carrying capacity and the deformation behaviour of mixed connections was investigated. Moreover, high‐resolution microhardness mappings (UCI) on the welded specimens were carried out to examine the formation of the soft zone in the heat‐affected zone of the high‐strength steels.
Cyclic behaviour of 3D cut welded connections with CHS columns and through I‐beams
Authors: Di Benedetto Sabatino , Latour Massimo , Francavilla Antonella Bianca , Rizzano Gianvittorio
Published: September 2023

This paper investigates the cyclic behaviour of a novel typology of steel beam‐to‐column connection made by welding circular hollow section (CHS) columns and through I‐beams. In fact, due to the novelty of this configuration and the lack of design equations in the current codes, the application of this innovative solution is limited in common practice.

The LASTEICON research project has recently investigated the main technological issues related to the manufacturing process and the joint's flexural resistance. Additionally, at the University of Salerno, studies on this joint began a few years ago, focusing on the characterisation of its bending response within the framework of the component method approach. Therefore, experimental, numerical and analytical activities have led to defining the joint's main components and proposing formulations able to predict the initial stiffness and the chord failure resistance. However, the proposed approach concerns the investigation of the monotonic behaviour of the joint, leaving the investigation of its cyclic response still unexplored.

To fill this gap, the cyclic flexural response of connections with CHS columns and through I‐beams is assessed in this paper, starting from the knowledge of the monotonic and cyclic behaviour of the main components of the connection.
Robustness of Sandwich Panels Subjected to Blast Wave
Authors: Studziński Robert , Malendowski Michał , Sumelka Wojciech , Gajewski Tomasz , Peksa Piotr , Sielicki Piotr W.
Published: September 2023

The paper presents results of a research on robustness of sandwich panels subjected to the accidental load – impact blast wave. The accidental design situation is understood as an unexpected explosion of gas cylinders located in the neighbourhood of the building. Full‐size sandwich panels with lightly profiled, thin‐walled, steel facings and thick softcore were used in the experiments. The conducted field tests allowed for FE model validation in Abaqus/CEA environment. During the experiments, the two high‐speed cameras have been used to record the behavior of the sandwich panel. Furthermore, the failure mechanisms of the sandwich panels and fasteners were also revealed. The research outcomes are based on both field experiments and numerical simulations.
Linear elastic buckling of composite beams – An analytical engineering approach
Authors: Derks Johannes
Published: September 2023

This article outlines a concise and complete versatile novel analytical framework to quickly and effectively assess lateral shear and lateral torsional buckling of composite beams build of segments with different lengths. The adjective “composite” includes dissimilar beam profiles with symmetrical homogeneous and or inhomogeneous cross‐sections and distinct beam materials. The major aim is to provide engineers with an accurate, simple but elegant analytical beam buckling tool based on advanced solid theoretical propositions. The justification of the analytical theory is supplied by demonstration of executed numerical tests, which affirm the validity of the proposed analytical buckling models adapted to the considered beam buckling cases.
Investigations on the system reliability of composite beams by transferring brittle and ductile Daniels systems to the shear connection
Authors: Wolters Kevin , Rittich Nils , Nonn Jonas , Feldmann Markus
Published: September 2023

In the design of a composite beam, the load‐bearing capacity of a shear connector is assumed to have its design value PRd. But a shear connection consists of dozens to hundreds of connectors whose individual capacities are scattered and randomly distributed. Thus, the load‐bearing capacity of the shear connection is usually higher than the capacity assumed in design n · PRd.

In 1945, H. G. Daniels described the system reliability of ideal elastic‐brittle fibre bundles with force redistributions after failure of individual fibres. In many cases the system reliability increases for few elements. And it increases continuously for ductile elements.

This article shows a reliability analysis of ideal Daniels systems with brittle and ductile elements. For the shear connection, the ideal Daniels system is extended to unequal load distributions in the shear connection of a composite beam. In parameter studies, the influence of the number of connectors on the system reliability of the composite beam is investigated for different boundary conditions. Again, an increase in reliability can usually be observed with only a few shear connectors. Conversely, if the reliability should remain the same, the design level of the shear connection could be raised by adjusting the partial safety factor γV.
Ductility classes in prEN 1998‐1. Comparative analysis on concentrically braced frames
Authors: Ştefănescu Bogdan Cătălin
Published: September 2023

In case of severe earthquakes, a ductile behaviour of the structure is desirable. The post‐elastic behaviour ability of a structure is generally managed in seismic design codes by means of the ductility class of the structure. The future version of the European standard prEN 1998‐1‐1 [1] defines three such classes, DC1, DC2 and DC3, with different meanings than the existing DCL, DCM and DCH in the current version of EN 1998‐1 [2]. A question that arises is whether a less elaborated structural analysis and design, involved by DC1 or even DC2 structures could finally lead to a more cost‐effective solution than a DC3 structure, which requires more sophisticated analyses and more careful design. Several answers can be obtained for each type of structural system. This paper focuses on the differences that can be highlighted in the design of concentrically braced frames according to the three new approaches. A concentrically braced structure was analysed to test the results for the three possible approaches. Three solutions were obtained using the requirements defined for DC1, DC2 and DC3. All three structures were designed based on resistance requirements. The material consumption and the post‐elastic behaviour were observed for each one of the three structural solutions.
Local buckling response and design of stainless steel hollow sections at elevated temperatures
Authors: Quan Chunyan , Kucukler Merih
Published: September 2023

The structural behaviour and design of stainless steel hollow sections in fire, including stainless steel (i) circular hollow sections (CHS), (ii) elliptical hollow sections (EHS), (iii) square hollow sections (SHS) and (iv) rectangular hollow sections (RHS), are explored in this paper. Shell finite element models of stainless steel CHS, EHS, SHS and RHS able to replicate their structural response at elevated temperatures are created. Numerical parametric studies are performed on cold‐formed and hot‐rolled austenitic, duplex and ferritic stainless steel CHS, EHS, SHS and RHS subjected to (i) pure compression, (ii) pure bending, (iii) combined axial compression and bending and (iv) combined bending and shear in fire, covering different cross‐section slendernesses and elevated temperature levels. Calibrated against the benchmark structural performance data obtained from the numerical parametric studies, the new design proposals for predicting the ultimate resistances of stainless steel CHS, EHS, SHS and RHS in fire put forward in Quan and Kucukler [1,2] are set out. It is demonstrated that relative to the design recommendations provided in the European structural steel fire design standard EN 1993‐1‐2, the proposed cross‐section design methods provide more accurate and safe‐sided ultimate resistance predictions for stainless steel CHS, EHS, SHS and RHS at elevated temperatures.
GMNIA‐based design of stainless steel structural systems
Authors: Walport Fiona , Chan Hou Un , Gardner Leroy , Nethercot David A.
Published: September 2023

Design by GMNIA (Geometrically and Materially Nonlinear Analysis with Imperfections) allows the key behavioural features of structures to be directly captured in the analysis, dramatically reducing the need for subsequent design checks. Since the analysis of frames typically employs beam finite elements, which do not explicitly account for local buckling, cross‐section classification and capacity checks remain necessary. To resolve the step‐wise and overly conservative nature of traditional checks, the alternative use of strain limits, defined using the Continuous Strength Method, has been proposed. The framework allows cross‐sections of all classes to be treated in a consistent manner, and results in an accurate and consistent representation of the true behaviour of structures. To date, the accuracy of the design approach for stainless steel has been comprehensively demonstrated for isolated stainless steel members; the design method is extended to indeterminate stainless steel structural systems herein. The method is included in AISC 370 and prEN 1993‐1‐14; inclusion of this design framework in international codes of practice presents a step change for the future direction of efficient structural stainless steel design.
Metal additively versus conventionally manufactured structures – An environmental life cycle assessment
Authors: Hadjipantelis Nicolas , Shah Izhar H. , Walter Lulu , Myers Rupert J. , Gardner Leroy
Published: September 2023

The use of wire arc additive manufacturing (WAAM) in conjunction with topology optimisation enables the production of structural components with significantly higher strength‐to‐weight ratios than conventional structural components. However, owing to the additional production stages involved in WAAM (e.g. arc welding), a common question arises regarding the environmental impacts of using WAAM to produce structural components relative to conventional fabrication techniques (e.g. hot‐rolling.) A cradle‐to‐gate life cycle assessment is conducted herein to compare the environmental performance of a conventional hot‐rolled I‐section steel beam with that of a topologically optimised WAAM beam, the latter having 53% lower mass than the former. With regards to climate change, it is demonstrated that, for a typical deposition rate of 2 kg/h, WAAM can lead to lower CO2‐eq. emissions than conventional hot‐rolling if topology optimisation can offer mass reductions of at least ∼50%. The contribution of the individual processes in WAAM production is analysed, demonstrating that the use of shielding gas is the greatest contributor to the climate change impact of WAAM production.
The Influence of Rib Distortion on the fatigue resistance of orthotropic plated bridge decks
Authors: Van Bogaert Philippe , Van Staen Gilles , De Backer Hans
Published: September 2023

Orthotropic bridge decks contain many places that are prone to fatigue damage due to the crossing of wheel loads of vehicles. Most research has focused on the rib to deck plate detail that has limited fatigue strength, especially due to the joint weld between these two parts. Less attention has been given to the effect of the alternating distortion stresses in the web plate of closed ribs. This distortion occurs as the rib passes through the web plate of the cross beams and is particularly pronounced if there is a high cope hole in that web plate. Experiments have been carried out in on this distortion effect at Ghent University. During 2 series of tests, similar results for the vertical rib web stress were found. However, these stresses due to distortion combine with longitudinal bending stress of the rib web and with shear. The corresponding strains were found from rosette measurements. These stress variations must be combined for fatigue assessment. This requires to use hot spot stress. In theory, the variation of the principal stress should be compared with the hot spot stress limit. This limit value is of course different for the 2 principal directions of the stress variations. This type of multi‐directional stress variations is addressed in codes, yet not exactly applicable in the present problem. Therefore, the modified critical plane offers a solution and gives more favourable results with longer fatigue endurance. In particular the Findley criterion that uses normal stress instead of shear, proves to be efficient in this type of problem. In order to link the results to simpler calculations, an attempt has been made to constitute a graph, which should allow a quick approximation for a first design.
Opening gates in flood protection barriers along the North Sea Coast
Authors: Van Bogaert Philippe
Published: September 2023

Due to the effect of climate change, a rise in sea level has become unavoidable. Only 2 solutions are left: either to return large parts of the land to the sea, or to build obstacles and dikes to prevent the flooding. The latter is the most obvious. In Belgium, the 65 km long coastline, including the ports of Ostend, Zeebruges and Blankenberge, as well as the port and the City of Antwerp are risk areas for flooding. That is why an extensive plan of low walls has been drawn up, which will be built in the high‐risk areas. Evidently, openings are needed in these walls, so that emergency vehicles, or other necessary objects, can be brought to the beach. Movable sliding gates have been provided for this, which can be permanently closed in the event of spring tides or later on for more permanent situations. The most difficult point appears to be the load due to the seawater that must be assumed. However, it seems the load due to debris can be more detrimental than the wave action itself. Since one becomes fairly certain of future floods, these loads should no longer be regarded as accidental, but should be assigned a higher partial safety.
An experimental investigation into span length effect in composite CFS and timber‐based flooring systems
Authors: Raffoul Samar , Sun Yao , McCrum Daniel
Published: September 2023

Cold‐formed steel (CFS) panelised built‐offsite modern methods of construction offer economy of scale, high precision, reduction in construction waste and a more streamlined manufacturing and construction process, compared to traditional construction. Floors made with CFS joists and timber‐based flooring systems, often jointed using screws and structural adhesives, have become increasingly popular. Nevertheless, the beneficial effect of the timber flooring on overall floor structural behaviour is often ignored in design due to limited understanding of CFS joist‐timber board interaction and the effect of various influencing parameters. This article investigates, experimentally, the structural performance of such composite floors. This paper presents eighteen large scale bending tests of CFS composite floors and five pushout tests to investigate the effect of span length on composite action. The results demonstrate that a high degree of composite action can be achieved when both screws and adhesives are utilised, resulting in around 40% increase in flexural stiffness when compared to joist performance without boards. This can lead to a more efficient and sustainable design of CFS joisted floors. The results also show that further research is needed to extend existing design equations to cover short span lengths.
Fatigue behavior at flange thickness transitions with cope holes – design model for engineering practice
Authors: Derler Christoph , Unterweger Harald , Knobloch Markus , Röscher Stefanie
Published: September 2023

Flange thickness transitions are common constructional details in welded girders, such as crane runway girders or main girders of highway and railway bridges, to adapt the bending moment capacity of the girder to variable bending moment distributions. At these details the transverse butt weld is often decisive for the fatigue verification of the member. Based on comprehensive studies at Graz University of Technology, including also two fatigue tests, stress concentration factors for the fatigue verification of the butt welds at the girder flange were developed. However, due to the complex local stress fields at the flange thickness transition, cope holes were not included in these studies.

Within a research cooperation of Graz University of Technology and Ruhr University Bochum, flange thickness transitions with cope holes are studied recently. Based on comprehensive numerical FE‐ calculations within the practically relevant geometric parameter range, the complex local stress fields near the cope hole are analyzed both, within the web and the flange plate. For validation of the FE‐model also strain measurements were carried out at large‐scale test girders. Applying the hot spot stress method, the decisive hot spots are determined, and a simplified design model is developed for an accurate prediction of these hot spot stresses.

The paper presents this design model in detail and shows its accuracy ‐ compared to the FE‐results ‐ for a wide range of different geometrical conditions, as used in practice (e.g. variation of girder dimensions, flange thickness ratio, tapering to the outside and to the inside).

Finally, also the results of full‐scale fatigue tests on two different welded girders with flange thickness transitions and cope holes are presented. This provides an accurate fatigue resistance for the proposed design model, based on the hot spot stress method.
Development of Novel Inter‐module Connection for Composite Modular Tall Buildings
Authors: Kandel Arjun , Thai Huu‐Tai , Ngo Tuan
Published: September 2023

The emerging modular building construction technique is gaining attention by researchers and investors because of its benefits such as short construction time, better quality control, minimal environmental effect and more economical. Composite modules have many advantages, including size reduction and improved fire resistance, over the steel modules, which encourage the application of modular construction on tall buildings. Current state‐of‐art lacks the proper connection technique for composite modular tall buildings. This paper presents novel inter‐module connection for composite modular tall buildings. Purposed inter‐module connection is very simple in geometric design, adequately strong to bear loads for tall buildings, easy to connect and disconnect, and applicable with internal joints and composite modules. Bolts through bolt holes connect modules vertically whereas gusset plate connects horizontally. Firstly, prototype is developed, and workability is confirmed. Performance and failure mechanism of proposed connector under tensile load are evaluated considering the effect of different parameters such as thickness of base plate, size and material of bolt. Results can be used to develop the design guideline for proposed inter‐module connection.
Analytical investigations of seismic performance of different joint details for composite RCS frames
Authors: Murari Krishna , Kumar P. C. Ashwin , Shiradhonkar Saurabh
Published: September 2023

Composite RCS frames, comprising of Reinforced Concrete (RC) column and Steel (S) beam are gaining popularity as an attractive alternative to traditional steel moment frames for mid to high‐rise buildings as well as conventional RC construction for low‐rise buildings. The prime concerns with RCS frames are constructability and load transfer at beam‐column connections. Over the last 30 years, several joint details, viz. face bearing plates, erection steel columns, vertical joint reinforcement, and steel band plates have been proposed for RCS frames. The moment‐rotation behavior of these joints was established through quasi‐cyclic experimental programme. The moment‐rotation characteristics of RC column‐S steel beam joint significantly affect seismic performance of the overall frame. The objective of this paper is to evaluate the seismic performance of low and mid‐rise RCS moment resisting frames with different connection details, available in published literature. The nonlinear analyses of differently jointed RCS moment resisting frames is carried out and performance assessed in terms of collapse capacity and the available response reduction factor, Ravl. Seismic collapse risk of RCS frames is estimated to understand performance under uncertain ground motion.
Algorithm for the plastic analysis of arbitrary steel cross sections based on finite element formulations
Authors: Ibáñez Stalin , Kraus Matthias
Published: September 2023

In structural engineering verifications, the plastic capacity of steel members may be utilized for cross sections of class 1 and 2. In literature, algorithms for the primary torsional capacity considering different types of numerical procedures, such as finite element methods, have mainly been addressed. However, there is a lack of explicit illustration of algorithms for cross sections considering combined loading, i.e. procedures for bending and torsional analysis. This paper therefore presents an algorithm for the plastic analysis connected to a cross‐sectional finite element approach. The algorithm considers the description of bilinear material laws, accounting for ideal‐plastic behavior as well as effects of isotropic hardening. Cross sections are discretized by isoparametric two‐dimensional nine‐node elements with curvilinear boundaries, which allow describing any geometry with high accuracy. The study proves that the plastic algorithm combined with the isoparametric elements accurately represents the behavior of cross sections. In addition, precise cross‐sectional capacities of hot‐rolled U‐sections gained by the methodology, i.e. plastic torsional moments and plastic bending moments, are presented. In future research, this methodology will be combined with finite element formulations for beams.
Experimental Study on Fire Performance of Polymer Foam Cavity Insulated Light Steel Framed Walls
Authors: Ščapec Tomislav , Skejić Davor , Rukavina Marija Jelčić
Published: September 2023

Light steel frame (LSF) building systems are a fast, reliable and economical construction system for residential and non‐residential buildings. Since the thermal conductivity of steel significantly limits the effectiveness of such wall systems for use in modern energy‐efficient buildings, adequate thermal insulation is essential. For this reason, numerous research studies have been conducted on LSF structures with different types and positions of thermal insulation. Due to the combustible nature of polymer foam, LSF systems insulated with this type of insulation have not been the focus of this research. On the other hand, polymer foam is ideal for automated industrial production of prefabricated load‐bearing LSF walls, and research on such walls is mandatory. In this paper, the fire test results of two innovative LSF walls with polymer foam insulation and different gypsum fibreboards are presented. In the proposed configuration, spacers are also used to prevent direct contact between the wall panels and the steel studs. The study conducted shows that a suitable configuration of gypsum fibreboards can lead to satisfactory fire resistance of energy‐efficient LSF wall systems with polymer foam.
Deep Neural Network Direct Stiffness Method: Fundamental Steps into Beam Design
Authors: Mueller Andreas , Taras Andreas
Published: September 2023

This paper presents a novel approach for performing beam element analysis that considers the nonlinear deformation behavior of various RHS and SHS sections made of mild to high‐strength steel: the Deep Neural Network Direct Stiffness method (DNN‐DSM), which uses Deep Neural Networks (DNN), a subset of machine learning algorithms and more general artificial intelligence approaches, to predict the nonlinear stiffness matrix terms in a beam element formulation for implementation in the direct stiffness matrix (DSM). These predictions are made using trained DNN models drawn from an extensive pool of geometric‐material nonlinear simulations with additional imperfections (GMNIA) using shell‐based models. Initial implementations of this method are able to predict the nonlinear load‐displacement and moment‐rotation behavior of various cross sections with high accuracy. This combines the precision of shell analysis with the computational efficiency of beam element analysis. Previous publications have already demonstrated the suitability and advantages of this method, albeit on a small scale for local buckling prediction. This work goes beyond previous studies and focuses on finite beam element design. This includes a review of the modeling approaches of DNN‐DSM using experimental and numerical results from literature.
Innovative orthotropic deck strengthening design for the Suurhoff lifting bridge
Authors: Rikken Maarten , Csillag Fruzsina , Sonneveld Michelle , Gration David , Gibson Rupert , Montalbini Gianmarco
Published: September 2023

From 2018, a significant amount of deck plate cracks have been discovered on the movable part of the Suurhoff bridge. These cracks reduce the strength of the bridge and might lead to unplanned hindrance and costly repairs. Renovation of the ortho‐tropic steel deck was chosen instead of frequent inspections and repairs or replacing the structure from a risk and cost perspective.

The innovative strengthening scheme consists of the addition of a steel plate which is connected to the top of the existing deck plate by a combination of preloaded‐injection bolts and epoxy. The strengthening steel plate reduces the stress in the existing deck plate thereby improving the fatigue performance. The new and old steel work compositely due to the combined effect of bolts and epoxy resulting in a relatively light‐weight strengthening scheme. The design followed a risk‐based approach in which Arup closely collaborated with Rijkswaterstaat, contractors and research institutions to finish the full design and implementation in less than a year. The design objective is to provide at least 15 years additional fatigue life for the existing deck.

The design was developed with the help of a combined numerical and experimental campaign. The novelty of the strengthening scheme and the use of different materials required experimental validation on small and large scale. The extensive validation resulted in sufficient confidence for the Rijkswaterstaat to implement this innovative scheme on an important bridge in The Netherlands. This scheme is especially beneficial from a weight and construction time perspective and therefore suitable for further implementation on other bridges.
Structural behaviour of built‐up battened cold‐formed steel columns
Authors: Craveiro Hélder D. , Rahnavard Rohola , Santiago Aldina , Laím Luís , Simões Rui
Published: September 2023

Built‐up cold‐formed steel (CFS) columns are extensively used when single cold‐formed steel elements are not able to fulfill the established requirements in terms of load‐bearing capacity. For hot‐rolled steel laced and battened columns, the EN 1993‐1‐1 presents specific design provisions. However, no specific design guidelines are provided for CFS laced and battened columns. The investigation on this type of built‐up elements is scarce, requiring extensive research to assess if the hot‐rolled design methodologies are also suitable for cold‐formed steel elements. In this investigation, experimental and numerical results are presented for CFS battened columns comprising C and Σ channels. Assessing the composite action between the individual shapes connected by the batten plates was one of the objectives of this investigation. The predominant buckling modes were analyzed considering the influence of batten plate spacing and the number of fasteners per plate. Based on the obtained experimental results finite element models were developed to further assess the influence of key governing parameters. The observed axial strengths are compared with design strengths determined according to the Eurocode assessing the suitability of the design methodologies.
Experimental qualification of replaceable bolted links in dual eccentrically braced frames
Authors: Dubina Dan , Stratan Aurel
Published: September 2023

The performance of structures under severe seismic action is ensured by properly calibrated ductility, stiffness, and strength. The “plastic” members of ductile mild carbon steel (S235 to S355) dissipate the seismic energy, acting as “structural fuses”, while the “elastic” members must be provided with adequate overstrength, to have the capacity to carry the stresses corresponding to yielded and strain hardened plastic hinges. High strength steels, such as S460 to S690, might be used for these elastic members, providing them with the necessary overstrength, without enhancing the stiffness, as that could unbalance the structural system. Dual structural systems, as moment resisting frames (MRFs) combined with eccentrically braced frames (EBFs), can be equipped with replaceable mild carbon steel dissipative links acting as seismic fuses. The MRFs, possibly fabricated from high strength steel, remain elastic, being able to recover the initial position. The key problem in such systems is the design and calibration of the fuses, i.e. the replaceable bolted links, which should be carefully qualified by tests. The present paper reviews past research on bolted replaceable links and discusses the experimental qualification requirements.
Experimental and numerical study of a damage‐free self‐centring link for seismic resilient EBFs
Authors: Lettieri Annarosa , Freddi Fabio , Latour Massimo
Published: September 2023

Significant progress has been made in recent years for the definition of seismic‐resilient structures, chasing the urgent need for structures able to return to undamaged, fully functional conditions in a short time after an extreme event. Seismic‐resilient steel structures have been widely investigated, mainly considering solutions based on moment‐resisting and concentrically braced frames. However, while the first category may be characterised by low stiffness, the second is often characterised by low ductility. Eccentrically Braced Frames (EBFs) allow overcoming these drawbacks and well‐balance stiffness, strength and ductility. This paper presents the numerical and experimental study of a damage‐free self‐centring link for EBFs. The proposed device uses post‐tensioned bars to control the self‐centring behaviour and friction devices to provide dissipation capacity. Experimental cyclic tests have been carried out to evaluate the response of the device. A 3D ABAQUS model has been developed to investigate the local response. Finally, a six‐storey EBF has been numerically investigated in OpenSees to evaluate the global response. Incremental Dynamic Analyses were performed demonstrating the increased seismic performance of the proposed solution.
Experimental evaluation of the ultimate strength of wall sandwich panels under transverse loads
Authors: Dinu Florea , Neagu Calin , Senila Mihai , Dubina Dan , Ungureanu Viorel
Published: September 2023

Light weight panels are largely used for the envelope (wall assembly, roofing system) of different kind of commercial or industrial buildings. They are typically designed from the weather/climate related conditions of the site (climatic actions, thermal comfort). Despite their low weight, they have adequate load carrying capacities under transverse loads. However, under extreme loading conditions, like very heavy winds or external explosions, such walls can be damaged or destroyed, under either positive or negative pressures. The study presented in the paper describes the results obtained on wall sandwich panels tested for transverse loading until complete failure. The panels are arranged as single span systems supported on side rails and loaded at the mid‐span. After a quasi‐linear response, the maximum flexural strength is reached. Then, due to a local dynamic instability, a sudden drop in capacity is recorded, followed by a second increase in capacity due to development of catenary forces. If the end fasteners have adequate resistance, the ultimate capacity in the catenary stage can be significantly higher than the peak flexural capacity. The ultimate capacity depends also on the stiffness of the support system (side rails and columns).
Imperfection Sensitivity of Plastic Shear Buckling Behavior in Corrugated Web Stainless Steel beams
Authors: Amani Mozhdeh , Al‐Emrani Mohammad , Khalili Shahriar
Published: September 2023

The shear behavior of corrugated web beams can be highly sensitive to the presence of initial imperfections. The designer has, in general, no prior information about the mechanical and geometric imperfections of welded elements. As a solution, in a FEM‐based design, the eigen buckling deformations with an equivalent maximum magnitude are included as an equivalent initial imperfection in a nonlinear analysis to account for the simultaneous effects of geometric imperfections and residual stresses. Previous researchers investigated the effects of initial imperfections in the form of different eigenmodes found via linear buckling analysis. They concluded that the shear strength rises with mode number, with the first mode providing the most crucial condition. However, it is shown in this paper that such a methodology is not applicable to stainless steel corrugated web beams in the medium slenderness ratio range when shear yielding precedes shear buckling. It is observed that, unlike in elastic buckling, in plastic buckling the first buckling mode does not result in the minimum strength. The results show that in FEM‐based design, using the first mode instead of the critical mode as the shape of the initial imperfection can result in a maximum of 19% and 31% overestimation of the ultimate shear capacity for the imperfection amplitudes of tw and hw/200, respectively.
Effective seismic retrofitting concept for existing car park buildings in moderate seismic regions
Authors: Terehovich Vladislav , Balaskas Georgios , Don Rafaela , Hoffmeister Benno
Published: September 2023

Carparks are highly systematic and standardized building typologies. As enduser requirements are almost the same throughout Europe, carpark buildings can be easily categorized according to their geometry and structural system. Split‐level carparks are common practise, especially for city‐centre areas. However, their assembly includes some inherent disadvantages regarding the seismic performance. In the light of the new National Annex in Germany (DIN‐EN‐1998‐1/NA) the seismic performance assessment of existing buildings gains increasing importance in areas of low‐to‐moderate seismicity as well. This paper describes the assessment of the seismic performance of an existing multistorey carpark, built in Aachen (Germany) in the 1980s and proposes an efficient, low‐cost pre‐earthquake strengthening strategy. The investigated structure consists of steel‐concrete‐composite floors and concentrically‐braced frames (CBFs) in both longitudinal and transverse direction. Brace‐to‐beam/column connections represent the weak point of the structure, as their capacity is lower than the tensile/compressive resistance of the braces. An unconventional low‐cost retrofitting strategy by means of “weakening” the existing hollow‐section‐braces is investigated and discussed in this contribution.
Life Cycle Cost and Life Cycle Assessment of Composite Bridge with Flat and Corrugated Webs
Authors: Hlal Fatima , Amani Mozhdeh , Nilsson Peter , Hollberg Alexander , Al‐Emrani Mohammad
Published: September 2023

To satisfy the sustainability criteria, a bridge design must be economically viable during its entire service life with a minimal impact on the environment. While stainless steel is known for its excellent life cycle performance, its high cost prevents it from being used in bridges to a larger extent. This study evaluates a new design solution that takes advantage of using corrugated web in bridge girders to overcome this issue. Three design concepts are evaluated for a three‐span case‐study bridge. These include a bridge with carbon steel flat web, stainless steel flat web, and stainless‐steel corrugated web girders. Each design is optimized using a genetic algorithm. The three optimal solutions are then evaluated in terms of investment costs, life cycle costs (LCC) and life cycle impact. The results show that the investment costs in a flat web girder bridge increase by 27% when stainless steel is used instead of C‐Mn (carbon) steel. However, this increase is only 10% when corrugated web girders are used. On the other hand, the LCC savings increase from 6% to 18% for corrugated web girders. Finally, the use of corrugated web in stainless steel leads to a reduction in the climate impacts of up to 32% compared to carbon steel for the studied bridge.
Predictive modelling of the cross‐sectional reduction of smoke extraction ducts under fire resistance test
Authors: Mundó Ignasi , Ichard Mathieu , Caner Ferhun , Mateo Antonio
Published: September 2023

In‐service performance of single compartment smoke extraction ducts is evaluated in the fire resistance test with the method described in EN 1366‐9. Failure due to cross‐sectional reduction is caused by the deflections of the steel walls which are exposed to a differential pressure and a high temperature airflow coming from the furnace.

This study presents a methodology for the prediction of the deformation of smoke extraction duct steel walls using 1‐way transient coupling between computational fluid dynamics (CFD) airflow simulation and mechanical finite element analysis (FEA). The resulting deformation is compared with a full‐scale experimental test. The degradation of the steel mechanical behavior with temperature is calibrated using experimental data. This coupled analysis provides insights into the tools and methodology developed for the digitalization of fire resistance testing.
Seismic Design of Non‐Structural Components in Industrial Facilities – a Discussion of the EC8 Approach
Authors: Knoedel Peter
Published: September 2023

In industrial facilities, equipment such as production machines, small vessels, conveyors and piping are installed at various elevations of the (building‐) structure. In seismic design, this equipment (referred to as non‐structural components) should be considered integrally with the structure in order to capture the resulting dynamic behaviour of the system adequately.

However, the typical procedure in plant construction is to design the structure in a previous step, where masses of the equipment are introduced only by a rough estimate, and stiffnesses of the equipment are ignored. The seismic design of individual non‐structural components is done in a subsequent step and typically by the respective supplier of the component. He often does know little about the characteristics of the structure – mostly not even the natural frequency. If the equipment is to be installed in an existing structure (e.g. due to changes in the production process or exchange of components) or if existing components have to be re‐verified (e.g. due to new seismic design loads at site), it may be difficult to define the dynamic characteristics of the possibly many years old load‐bearing structure.

In Eurocode 8‐1 as in many other design codes, rules for the design of non‐structural components are given. However, some of these do not seem to be in accordance with mechanics or seem to be based on hidden assumptions. In any case the designer is left with what is felt to be an unsatisfactory design result, which cannot be retraced by the designer.

In the present paper, the structural behavior of typical non‐structural components is investigated: a silo on a structural grid, an elevated tube‐feet tank, and piping. For these, the dynamic behaviour is investigated, when built in a typical plant structure. The findings are compared with the design rules given in EC8‐1. Improvement of the rules towards better understanding of the mechanical background or better ease of use will be proposed.
Experimental campaign on components of steel frames for elevators
Authors: Baldassino Nadia , Bernuzzi Claudio , Simoncelli Marco
Published: September 2023

Architectural barriers are a very topical issue that affects the entire population, not just people with disabilities. In recent years, there is more and more talk of design of private and public spaces without architectural barriers that can hinder anyone's mobility. All of this concerns both new and existing structures. In new constructions the theme of accessibility is considered since the initial phase of the design process while in existing structures, depending on the specificity of the building ‘ad hoc’ solutions need to be identified and appropriately integrated into the building systems. In this last field, the problem of vertical accessibility is frequently solved by elevators which are frequently made of thin‐walled steel structural elements.

This work presents an experimental‐numerical investigation of thin‐walled profiles used for building steel elevator. The performance of two different cross‐sections under compression was studied. At this aim stub‐column tests of specimens having an axial force applied to the cross‐section centroid and with different eccentricities from the centroid were performed. Alongside the experimental study, a large numerical study was developed by using refined finite element models to simulate the experimental results. Numerical and experimental studies made it possible to draw the M_N sections domain which were compared with the theoretical ones obtained on the basis of the formulas provided by EC3‐1‐3. It is shown that for the considered profiles, the expression prosed by EC3‐1‐3 is from the safe side.