bluuebunny/crossref_metadata_2025 huggingface dataset:
Bearing failure analysis in the design of bolted connections with austenitic stainless steel
Authors: Sobrinho Kelvin de P. , da Silva André T. , Rodrigues Monique C. , Henriques José A. , Lima Luciano R.
Published: September 2023

The use of stainless steel in structures has been improved; nevertheless, the application of this material is not considered trivial by most designers, as there as still limited design codes providing specific rules. Current codes provide conservative approaches in certain cases, which do not corroborate with the objective of reducing the initial cost of projects incorporating stainless steel. In order to contribute to an adequate comprehension about the structural behavior of austenitic steel in bolted connections, a study was conducted regarding the influence of geometric parameters on the connections with a bolt under two shear planes, encompassing the evaluation of the phenomenon recognized as curling. Concerning to conclusions, it was observed that the geometric parameters e1, e2, d0, affects the curling effects, which has the potential to compromise the structural behavior of a thin‐plate connection if this deformation is greater than the thickness of the plate. Furthermore, the results provided by the equations employed in the design codes was assessed in this study, revealing an adequate prediction of the SCI in terms of the failure mode. However, both the manual and current codes exhibited conservative load for the investigated connections.
Closed built‐up cold‐formed steel columns under compression
Authors: Craveiro Hélder D. , Rahnavard Rohola , Santiago Aldina , Laím Luís , Simões Rui
Published: September 2023

Cold‐formed steel (CFS) structural profiles are extremely versatile enabling the combination of multiple individual cross‐section shapes to fabricate a built‐up member presenting enhanced structural performance (higher load‐bearing capacity and torsional stiffness). Built‐up members have the potential to contribute to further expanding the current use of CFS products in the construction industry. However, the existing design codes, such as the EN 1993‐1‐3 and AISI S100, do not present specific design methodologies for the design of such members, mainly due to a limited understanding of the complex behaviour of built‐up CFS members combining multiple components. The behaviour of built‐up CFS columns comprising 4 individual shapes was assessed through experimental tests and numerical modelling. The interaction between the different components and the influence of spacing between connectors was investigated using the finite element method, providing recommendations concerning the effective use of fasteners to attain composite action between the individual shapes. The suitability of the design codes, namely, Eurocode and North American design predictions, following to Effective Width Method (EWM) and Direct Strength Method (DSM), respectively, were assessed for the built‐up members.
Experimental Local Stability of 3D‐printed Stub Columns Stiffened by Sinusoidal Waves
Authors: Chater Ben , Wang Jie , Evernden Mark , Pan Jingbang
Published: September 2023

Traditional structural steel manufacturing routes typically produce prismatic members comprising of flat plates. Under compressive actions, the capacity of these sections is often dominated by plate instability of the lowest buckling mode. To validate a new plate strengthening method by assigning ‘higher‐order’ 2D sinusoidal waves to plated structures, this study involves experimental testing of 3 prismatic SHS stub columns and 6 non‐prismatic members strengthened by this method. The test samples were 3D printed in 316L stainless steel using Selective Laser Melting. Tensile coupon tests were carried out on samples printed from the same material to obtain the material properties. It was found that the yield strength increases with the plate thickness whilst ultimate strength remains approximately unchanged. The stub column test results show that assigning 2D sinusoidal waves to EAS flanges can bring different levels of strength enhancement compared to their prismatic counterparts, depending on the section slenderness and the wave amplitude. The best case evaluated within this study indicated a strength gain of 31% over the prismatic section with only a 3.2% increase in used material. It makes an important step in bringing this technology towards feasibility by verifying previous numerical results, paving the way towards unprecedented efficiency in future steel structures.
Load capacity of penstock manifolds subjected to increasing settlements at the vertical supports
Authors: Langwieser Martin , Ecker Alexander , Unterweger Harald
Published: September 2023

Hydroelectric power plants usually have penstock manifolds near the powerhouse, including individual bifurcations to provide several turbines. These steel constructions have numerous vertical supports and are designed based on linear elastic behaviour, leading to very small allowable settlements at the supports.

For a representative built manifold, with five bifurcations (six branch pipes), the elastic‐plastic load capacity was studied in detail, assuming dead load, internal pressure and increasing settlements at the supports. Different settlement patterns were studied. The development of plastic zones was analyzed, depending on the rate of settlement. Due to the high bending stiffness of the penstock manifold, the penstock detaches from the single supports due to the settlement, leading to a significant redistribution of the vertical reaction forces at the supports.

The comprehensive calculations show adequate robustness of the penstock manifolds, even though in case of very high settlements at the supports. Due to the significant redistribution of the reaction forces at the supports, these vertical supports must have an increased bearing capacity, in comparison to the reaction forces due to dead load and internal pressure based on linear elastic analyses.
Probability of detection curve for the automatic visual inspection of steel bridges
Authors: Kompanets Andrii , Leonetti Davide , Duits Remco , Maljaars Johan , Snijder H.H. (Bert)
Published: September 2023

The damage tolerant design philosophy is based on periodical inspections and provides safe bridge operation preventing fatigue cracks from growing up to a critical size. It is possible to optimize the management costs of a bridge throughout its life by designing the inspection frequency, which depends on the capabilities of the inspection method. However, such optimization requires knowledge about the performance of inspections that are envisioned to take place during the use of the bridge. Regular visual inspections is the most frequently applied type of inspection of bridge structures. Recent advances in computer vision technologies provide a strong basis for the development of automatic damage detection systems that can support regular visual inspection, thus increasing the reliability of the inspection. Several automatic crack detection systems have been developed in the past years. However, the performances of such systems have not been evaluated in the way as for traditional non‐destructive inspection methods, i.e. in terms of probability of detection curves and detectability limits. This restricts the applicability of automatic visual inspections for inspection planning and damage tolerant design. This paper proposes an encoder‐decoder neural network for segmentation of cracks on images of steel bridges. A probability of detection curve is calculated for this neural network.
A framework for multi‐element hybrid simulation of steel braced frames using model updating
Authors: Hosseini Anahita Sadat , Mokhtari Fardad , Imanpour Ali
Published: September 2023

This paper presents a framework for seismic response assessment of steel buckling‐restrained braced frames (BRBFs) by integrating data‐driven techniques into the conventional hybrid simulation to facilitate multi‐element hybrid simulation for structural systems with several potential critical components. The data‐driven brace model incorporates Prandtl‐Ishlinskii hysteresis model into a prediction algorithm to reproduce cyclic nonlinear response of the brace under random earthquake excitations. A two‐storey steel BRBF is selected to illustrate and verify the proposed framework using a set of virtual hybrid simulations. In the BRBF, the first‐storey BRB is virtually simulated, representing the test specimen, while the second‐storey BRB enjoys the data‐driven model trained based on past experimental data. The model parameters are updated in real‐time during hybrid simulation using the data received from the virtual test specimen. The results confirm that the proposed hybrid simulation technique can offer a viable solution to address the shortcomings of conventional seismic hybrid simulation by taking advantage of model updating and multi‐element simulation platforms.
Developed numerical Analysis of Residual Stress caused by Welding and Cutting in Steel Structures
Authors: Li Zheng , Xu Siying , Geißler Karsten , Wang Jian , Pasternak Hartmut
Published: September 2023

The welding and flame‐cutting process in the steel construction are commonly used, especially for the bridge structure. Some experiments about welding and cutting have been done separately by some researchers. The results from the experiments were also compared with the results from the numerical simulation under 3D or 2D models. The agreements between those results are as good as they predicted. Therefore, the numerical simulation is a better way to analyze the quality of the steel construction after welding and cutting without time‐consuming and a large amount of cost. But there are only a few research about the numerical simulation and the some of them are aimed to verify the experiments. In this study, the calculation about the residual stresses after welding and thermo‐cutting are considered from 3D‐model into 2D‐Model. The heat source model is simply regarded as curves of time and welding energy with the algorithm methods. And no matter the change of the parameters of the model and the heat source, the heat transfer and the residual stresses can be calculated with the 2D models as fast as possible. By the means of the finite element software Abaqus, the I‐profiles are easy to receive the job results with the input parameters. The influence of the welding and cutting process are visual and direct.
An innovative I‐shaped low‐yield steel shear damper directly connected to the concentrically braced frame
Authors: Kontoni Denise‐Penelope N. , Ghamari Ali , Kheiri Javad , Ilia Georgios
Published: September 2023

Shear dampers are known as famous seismic passive energy devices due to their suitable performance against seismic loading to improve the behavior of Concentrically Braced Frames (CBFs). The CBF system suffers from low ductility due to its compression member's susceptibility to buckling. By adding the shear dampers directly to the diagonal element members of the CBF, the dampers prevent the bucking of the CBF and improve the behavior of the system. Although the dampers pertain to high energy dissipation capacity, they reduce the ultimate strength and elastic stiffness of the system. To overcome the shortcoming, in this paper, utilizing low‐yield point steel to create an I‐shaped damper is proposed and investigated parametrically and numerically by the Finite Element Method (FEM). This damper is directly connected to the CBF's diagonal member. The results indicated that by using the proposed I‐shaped damper, the ultimate strength, elastic stiffness, and energy dissipation of the system are enhanced. Also, the damper prevents the bucking of the CBF, which causes the damages to be limited in the damper, and the CBF to remain in the elastic zone. Also, required equations were suggested to design the system.
Enhancing Energy Efficiency of Cold‐formed Steel Framed Walls with Vacuum Insulation Panels
Authors: Rajanayagam Heshachanaa , Upasiri Irindu , Poologanathan Keerthan , Gatheeshgar Perampalam , Nagaratnam Brabha , Kanthasamy Elilarasi
Published: September 2023

In the current evolving building construction sector, the use of cold‐formed steel frames (CSF) has gained popularity due to their fast, clean, and flexible constructability. On the other side, in terms of the energy efficiency of a building, the use of CSF has raised concerns due to their high thermal conductivity, especially in the case of external wall panels. Hence, it is crucial to examine the thermal performance of such wall configurations and find solutions to reduce heat loss through walls by lowering the thermal transmittance, which would ultimately enhance the energy efficiency of the buildings. Accordingly, this study focuses on analysing the thermal performance of external wall panels made of cold‐formed and thin‐walled steel‐lipped channel studs with plasterboard linings and vacuum insulation panels (VIP). 2D and 3D finite element models developed in ABAQUS were used to analyse the effect of using VIP, oriented strand board and plasterboard, and their positions on the thermal transmittance of the CSF walls. 70 numerical analyses were conducted on 35 wall configurations and the results obtained were checked against the U‐value requirements set by UK building standards. It was found that replacing oriented strand boards with plasterboards does not substantially affect the thermal transmittance of the wall. However, adopting VIP as an insulation material has shown a U‐value reduction of up to 77%. But again, the change in position of VIP in the wall cross section has no notable effect on the U‐value.
Design of aluminium Sigma sections for web crippling behaviour under Interior Two Flange (ITF) load case
Authors: Thirunavukkarasu Kajaharan , Alsanat Husam , Poologanathan Keerthan , Shanmuganathan Gunalan , Perampalam Gatheeshgar , Kanthsamy Elilarasi , Higgins Craig
Published: September 2023

Aluminium sections have been emerged in the industry due to the advantages such as light weight, resistance to corrosion, recyclability, and flexibility. While the construction industry is moving towards to modular construction trend, aluminium sections are considered as a vital key to achieve the desirable outputs of modular industry. Modular industry needs high performing structural elements as well as light weight elements to reduce the overall weight of the modules which directly affects the transport cost, flexibility of the modular connections, construction duration, capacity of the equipment or machineries and required numbers of construction workers for assemble. Hence, the requirement of light weight elements is evident, and the aluminium sections have been considered to replace the conventional sections. However, the structural performance of aluminium sections has to be analysed to check the appropriateness of utilization though it is reasonable. Hence, aluminium sigma sections were selected in this study to check their performance in the web crippling scenario under Interior‐Two‐Flange (ITF) loading case. Sigma sections were opted based on the merits including high torsional rigidity and resistance towards local and distortional buckling. Appropriate numerical approach was selected, and the procedure was validated with experimental results. Accordingly, comprehensive numerical investigation was carried out by including different parameters such as depth, thickness, yield, and ultimate strength and bearing length. Subsequently, the results were compared with all critical parameters and the results were provided. Suggestions and recommendations were stated to utilise the aluminium sigma sections in the industry.
Load transfer of circular reinforced composite dowel connector: a comparison of existing analytical equations
Authors: Paoletti Maxence , Schäfer Markus
Published: September 2023

The effectiveness of headed studs for shear transfer in the steel‐concrete interface of composite columns is questionable when important load needs to be transferred. Circular reinforced composite dowel (CRCD) connectors are known for their high initial stiffness and significant load‐bearing capacity. This paper presents the different types of CRCD connectors and the available analytical equations to determine their shear resistance, as well as a database of 52 experimental specimens to study their performance. The results show that the equations developed by Wang et al. 2014, He et al. 2016 and Zhao et al. 2016 provided the best performance, with 76% of the predictions falling within the error bounds of +/−15%. Further research is recommended to understand the behaviour of CRCD connectors on H‐shaped steel profiles and to develop analytical equations to calculate their resistance.
Finite Element Analyses of Demountable Shear Connection in Cold‐Formed Steel‐Concrete Composite Beam Based on Experimental Data
Authors: Žuvelek Vlaho , Ćurković Ivan , Lukačević Ivan , Rajić Andrea
Published: September 2023

There is a surging demand for innovations that would increase the value of construction elements and materials in their life cycle. Therefore, the subject of this research is the shear connection in the floor composite system of cold‐formed steel and concrete slab. Composite systems can be further improved by a demountable type of shear connection, which shows good performance compared to traditional solutions but also allow for system demountability, fulfilling some sustainability policy aspects. Here, two configurations of CFS‐concrete composite systems with bolted shear connections were considered. The first configuration considers two directly connected back‐to‐back CFS profiles, while the second considers two back‐to‐back CFS profiles spaced apart simulating the presence of a corrugated web in between. Based on the experimental results of the second configuration, the numerical model in ABAQUS was developed and calibrated. A detailed comparison of the two configurations has been carried out. Additionally, the behaviour of considered configurations was also analysed regarding the number of bolts within the rib of the concrete slab. The obtained results show that close spacing of the shear connectors can prevent the development of their full bearing capacity.
Experimental test setup design for ultimate limit state evaluation of ductile wrapped composite KK‐joints
Authors: Koetsier Mathieu , de Vries Peter , Peeters Tjeu , Pavlović Marko
Published: September 2023

Complex circular hollow section double KK‐joints are widely used in, e.g. offshore wind turbine jackets. As an alternative to conventional welded joints of the CHS multi‐membered structures, wrapped composite joints have shown superior structural performance in previous pilot tests. Experimentally characterizing the joint behaviour under uniplanar loading can be complicated, because of the ductile failure mechanisms of wrapped composite joints and second‐order bending moments. This paper presents the design of a test frame in combination with a conventional tensile 2.5 MN test rig. Ductile joint failure, joint imperfections and second‐order effects are considered in the design. Structural finite element software SOFiSTiK is used to analyse the effects of wrapped joint behaviour and imperfections on the test system and interaction of joint, frame and loading rig behaviours. Non‐linear joint behaviour and misalignments of the braces increased the second‐order effects significantly. Mitigation strategies have been explored to reduce additional bending moments in the KK‐joint. A complete test setup is proposed to perform static experiments on double KK‐joints in uniplanar axial loading conditions.
Experimental investigation of wrapped composite X‐joints under uniaxial and multi‐axial loading conditions
Authors: Koetsier Mathieu , Yang Jincheng , Wolters Mees , van Leengoed Berend , Pavlović Marko
Published: September 2023

Circular hollow section (CHS) multi‐membered structures, such as off‐shore wind turbine jackets and floating wind structures, face significant challenges under multiaxial loads. Wrapped composite joints have emerged as a promising alternative to conventional welded joints, offering superior structural and fatigue performance in previous pilot tests. This paper presents an experimental study on the failure mechanisms and load‐bearing capacity of wrapped composite joints under multi‐axial monotonic loading, using the Hexapod a six‐degree‐of‐freedom testing machine. The research question addressed in this study is to investigate the effectiveness of wrapped composite joints in resisting multi‐axial loads, and to understand the underlying failure modes. The experimental results demonstrate that the joints exhibit excellent resistance to uniaxial tension, uniaxial bending, and multi‐axial tension + bending loading, with failure modes including interfacial debonding, delamination, composite fracture, and steel yielding. Digital Image Correlation (DIC) and embedded optical fibers were used to monitor surface and interface strain. These findings suggest that wrapped composite joints offer significant resistance to multi‐axial loading.
Fatigue Life Prediction of S235 Details Based on Dislocation Density
Authors: Pedrosa Bruno , Correia José , Gripp Iara , Fernandes Lisete , Rebelo Carlos
Published: September 2023

Global approaches have been the main procedure to design structural details and components under fatigue loading. This procedure is easy to apply but it disregards not only the effect of the material type but also the influence of the geometry in complex components. On the other hand, local approaches rely on the specific local damage parameters that can be assessed for each type of material and detail geometry. The parameters derived from low cycle fatigue (LCF) tests are the most common damage parameters used to predict the fatigue life and establish reliable fatigue design approaches. Recently, Huffman proposed a fatigue damage model based on strain energy density and on the dislocation density of the material. In this regard, S235 was selected to perform a metallographic and mechanical assessment aiming to define the dislocation density of the material and to describe the fatigue behavior using the Huffman damage model. Additionally, fatigue tests on structural details (plate with hole) were conducted and results were compared with fatigue life predictions based on Huffman local approach. It was found that Huffman model based on dislocation density is a reliable approach to predict the fatigue life of structural steel details.
Study on ultra‐low cycle fatigue fracture of thick‐walled steel bridge piers
Authors: Li Shuailing , Zhuge Hanqing , Xie Xu
Published: September 2023

Steel structures with thick‐walled section tend to have local fracture before the occurrence of instability under strong earthquakes, which is termed as ultra‐low cycle fatigue (ULCF). In this study, a series of specimens made with structural steel Q345qC for bridge in China were firstly tested to investigate the ULCF fracture behaviour in material level. Based on the test data, three models for ULCF fracture were calibrated. Subsequently, the fracture behaviour of thick‐walled square section steel bridge piers were also investigated in component level. Moreover, the finite element global and submodels of steel bridge piers were established, and ULCF fracture initiation life was predicted by calibrated models and validated against test results. The research results showed that the crack firstly occurred at the bottom of piers under cyclic oblique loading, which was at the junction between base plate and bottom weld, and then, cracks propagated along the bottom weld metal which did not cause a decrease in strength capacity. Finally, the strength capacity of steel bridge piers began to rapidly declined as cracks propagated into base metal. The presented finite element global model can accurately simulate the cyclic behaviour of steel bridge piers, and the submodel has the ability of capturing the local stress and plastic strain. The fracture models accurately predicted ULCF fracture initiation life of steel bridge piers with the average discrepancy of 7.14%. The developed finite element analysis method considering ULCF fracture provides a solution for the further parametric analysis on ULCF fracture performance of steel bridge piers.
Experimental study on open core hybrid buckling restrained braces with different debonding layer geometries
Authors: Das Pallab Jyoti , Deb Sajal Kanti
Published: September 2023

This study evaluates performances of newly developed open core hybrid buckling restrained braces (OC‐HyBRB) with debonding layers of two geometries. OC‐HyBRB has an axial load‐carrying steel core, two steel restrainers and two 3‐mm‐thick highly deformable rubber debonding layers. Debonding layer is continuous in first specimen and discontinuous in second specimen. OC‐HyBRB is designed to dissipate energy at lower strain levels through shear deformation of debonding layers. However, restrained local buckling of core first about weak axis and then about strong axis after threshold axial strain (∼2%) contributes to energy dissipation at higher strain levels. Thus, OC‐HyBRB is capable of dissipating energy in a wide range of core strain levels. Both types of OC‐HyBRBs are investigated using a specially designed test setup under a cyclic loading protocol, applied using a servo‐hydraulic actuator. Experimental force‐displacement hysteretic behaviour are found to be stable for both the specimens with enhanced stiffness at higher axial strain. This would reduce the residual deformation of the OC‐HyBRB. Thus, newly developed OC‐HyBRB would provide a simple yet efficient energy‐dissipation device for seismic response control of structures.
Recent progress in computational predictions on fatigue and fracture resistance of steel connection joints
Authors: Xin Haohui
Published: September 2023

Steel structures are often subjected to cyclic loads, and sometimes to monotonic overloads, during the technical lifetime, which causes their performance degradation. Incidentally, they undergo progressive collapse, especially due to local failure of connections or joints. To ensure the overall integrity of the steel structures and to make sure the efficient transfer of the load between different components, it is necessary to evaluate the ultimate capacity and fatigue resistance of steel connections. Advances in material modelling and well‐controlled experiments at various scales in recent years have increased confidence in the finite element method as an effective way to predict the ultimate resistance and fatigue life. On examples of two common steel connections: bolted connection and welded connection, the recent progress will be presented in ductile fracture and fatigue crack initiation and propagation simulation.
Determination of overall factor for the application of the General Method based on plastic and strain‐limited N‐M interaction for composite compression members
Authors: ZOGU Pëllumb , SCHÄFER Markus
Published: September 2023

The design of composite compression members can be realized based on the General Method in accordance with Eurocode 4. This method represents a more sophisticated design based on advanced numerical analysis. It may be applied for any type of composite column. The General Method contains two steps; the first step is defined as the global nonlinear finite element analysis (GMNIA) accounting for all geometrical and physical nonlinear effect and considering geometrical and structural imperfection; while the second step represents the analysis on the cross‐section level, by N‐M interaction diagram to determine the overall safety factor γ0. EN1994‐1‐1 requires the N‐M‐Interaction based on the plastic resistance. However, often the General Method is provided for those section, where the plastic resistance is not representing the real behavior. Therefore, the question is discussed why the N‐M‐Interaction should not be developed based on the strain‐limited resistance considering the approaches for concrete stress‐strain curve in accordance with EN 1992‐1‐1 and for structural steel in accordance with prEN1993‐1‐14.

In this paper, the application of general method is investigated for different type of composite columns with N‐M interaction diagram evaluated with plastic and strain‐limited resistance. Results are compared and discussed in terms of overall safety factor γ0. Conclusions are provided for the further development of the General Method in Eurocode 4.
Experimental behaviour of optimized hybrid coupled shear walls
Authors: Natali Agnese , Morelli Francesco , Salvatore Walter
Published: September 2023

This paper shows the experimental structural behaviour of an optimized solution for hybrid coupled shear walls, which are seismic‐resistant systems composed of a reinforced concrete wall, with two side steel columns connected by beams ‐ the dissipative element. The optimized solution is proposed to upgrade the global behaviour of the system, with the aim of reducing the bending moment at the base of the reinforced concrete wall. Indeed, previous experimental tests demonstrated that the wall may suffer from early cracking at the base, despite the possibility of controlling the base bending moment thanks to properly balancing stiffness and resistance of the different components of the system. The optimized solution is numerically developed and designed with the philosophy of redistributing bending at the base of the wall by removing the lateral portions of the concrete and replacing them with a couple of steel hinged profiles, to control the deformations and absorb the torque. The central concrete part of the wall is kept but reduced to the minimum, to transfer the shear, only, reaching closely hinged‐like conditions. Two different solutions are proposed for the central reduced part of the wall: in the first case, the cross section is gradually reduced to the base, while in the second one, the wall is connected through a steel pin to the base. Both solutions are tested under monotonic load for a preliminary assessment of the actual benefits at the base of the wall compared to the original proposal.
Hysteretic behaviour of welded connections with highly inelastic panel zones
Authors: Skiadopoulos Andronikos , Lignos Dimitrios G. , Arita Masaki , Hiroshima Satoru
Published: September 2023

The current practice in capacity‐designed steel moment resisting frames (MRFs) worldwide allows for limited shear yielding in the column web panel zone. As such, inelastic deformations concentrate near the beam ends, thereby leading to flexural strength deterioration due to local buckling often at modest lateral drift demands. Experiments on post‐Northridge welded connections suggest that prior to a story drift angle of 5% rad, panel zone kinking does not induce fracture for panel zone shear distortions of up to 10γy. Within such a context, this paper presents an alternative design of a welded moment connection with highly inelastic panel zones. The connection features simplified weld details including a customised beveled backing bar that can be kept in place after the completion of the complete joint penetration welds at the beam flange‐to‐column flange joint. Full scale experiments suggest that the hysteretic response of the connection remains stable up until a story drift angle of 8% rad. The specimen did not exhibit visible structural damage prior to story drift angles of 4% rad, which are characteristic to a maximum considered earthquake. Modest local buckling occurred near the beam ends only after a story drift angle of 5% rad, which is a typical drift threshold in current collapse assessment methodologies. This paper summarises the primary findings of the experimental program for one of the test specimens.
Finite Element Modelling of a Transmission Steel Lattice Tower Based on LiDAR Point Cloud Data
Authors: Wrzosek Filip
Published: September 2023

This article presents an innovative modelling method, which can serve as a set of guidelines for future applications related to point cloud data processing of steel lattice structures used for FEA modelling purposes. This method is fully automated, resulting in repeatable results and saving time required for manual data processing. The study investigated two types of input point cloud data, aerial and terrestrial, and compared the resulting model to an idealized model based on design documentation. Results showed that the LiDAR point cloud data is a good source of information for reconstructing a geometric CAD model and can be implemented in FEA. The impact of point cloud data usage for FEA modelling is demonstrated by investigating differences between FEA results of the point cloud‐based and idealized models, allowing for an understanding of the influence of real‐life imperfections on force redistribution across the analyzed structure and ultimate forces reached by members loaded in compression. This modelling method and analysis can serve as guidelines for future applications related to point cloud data pro‐cessing of steel lattice structures used for FEA modelling purposes.
Fatigue strength of tubular welded connections in offshore floating platforms
Authors: Papatheocharis Theocharis , Plakias George T. , Zervaki Anna D. , Karamanos Spyros A. , Perdikaris Philip C.
Published: September 2023

The work reported in the present paper is part of a European research program aimed at developing a hybrid tension‐leg floating platform, suitable for combined offshore wind and wave energy exploitation. Eight (8) fatigue tests on welded tubular joint specimens are performed, which represent the full penetration brace‐to‐cylindrical column welded connections of the project prototype structure. The large‐diameter columns are reinforced internally with a grid of longitudinal and transverse stiffeners fillet welded to the shell. The specimens are approximately 1/6‐scale physical models made of S355 grade steel, and subjected to cyclic loading under constant load amplitude histories. The brace‐to‐cylinder welds are semiautomatic, and high‐frequency mechanical impact treatment is applied in four specimens. The experiments are supported by post‐fracture metallographic examination and finite element analyses. The results indicate two locations for fatigue crack initiation: brace‐to‐cylinder crown and cylinder‐to‐stiffener connection.
Burnout resistance of concrete‐filled steel tubular (CFST) columns under realistic fire conditions
Authors: Szymkuc Wojciech , Malendowski Michal , Glema Adam
Published: September 2023

In this paper, we investigate the structural behaviour of concrete‐filled steel tubular (CFST) columns under various fires. Our contribution is based on two fire scenarios in modelled FDS with subsequent 3D FE numerical analysis (Abaqus), where material properties are defined for heating and cooling using user subroutines. Our goal is to examine the burnout resistance of CFST columns under different realistic fire scenarios involving varying number of burning cars.

The loss of compressive strength of concrete due to high temperature is irreversible. Hence, the burnout resistance is affected by the field of the highest temperatures reached inside the column. Moreover, the pre‐existing load affects the deformation of the column during heating and influences the post‐fire behaviour. The analysis is performed in several steps: first, results from the CFD models are extracted and appropriately mapped, then the heat transfer analysis between fire and solid is performed, and the resulting temperature history of the CFST column is calculated. Subsequently, a mechanical analysis is performed, where (1) the column is loaded, (2) the analysis of the column's structural fire behaviour is carried out, (3) if the column sur‐vives burnout, then in the last step, it is loaded until failure.
Performance of short links with flush and extended end plate connections using FEM analysis
Authors: Plaitano Francesco , Stratan Aurel , Chesoan Adriana , Nastri Elide
Published: September 2023

Eccentrically braced frames are commonly used as a seismic resistant system, due to the good balance of stiffness and ductility. Bolted links have been proposed in the past to allow replacing the damaged dissipative components following a strong earthquake. The goal of this research work is to investigate the influence of the connection type on the performance of bolted links using the Finite Element Analysis. Numerical models of links are first calibrated using past experimental tests. Modelling criteria adopted to replicate the experimental behaviour of the links highlighted in the tests are reported. The achieved results obtained regarding a flush end plate bolted link and an extended end plate bolted link with different lengths are then used as benchmark to assess the influence of the link length and type of connections adopted on the response of the links. The Finite Element Method is used to investigate alternative solutions to the tested ones. Finally, the investigated options are compared to determine the advantages and disadvantages of each solution.
In‐plane quasi‐static tests for the evaluation of seismic demand on Power Actuated Fasteners (PAF)
Authors: Fiorino Luigi , Campiche Alessia , Grzesik Peter , Landolfo Raffaele
Published: September 2023

Recent research showed that the damage in non‐structural components significantly affects the seismic behaviour of structures, indeed it is crucial to evaluate the seismic behaviour of non‐structural components. For this purpose, the University of Naples “Federico II” started a cooperation with the Hilti Corporation, to evaluate the seismic demand on fasteners connecting drywalls to supporting elements. In particular, the seismic displacement demand on Power Actuated Fasteners (PAF) was obtained through quasi‐static in‐plane cyclic tests on full‐scale drywall partitions.

Test specimens consisted of 2285 mm long and 2600 mm high partition walls and in total seven tests were carried‐out at the Lab of the Department of Structures for Engineering and Architecture. A specific test set‐up was developed for the experimental tests and the optimal instrumentation layout was studied to allow to capture the significant measurements on PAFs. A FEMA 461 protocol was employed for all the tests.

The paper summarizes the experimental program, describing wall configurations, test set‐up, loading protocol and instrumentation layout. A special focus is dedicated to the comments of experimental results.
Assessment of Eurocode 3 Shear Design Provisions for Cold‐Formed Steel Beams with Web Holes
Authors: Gatheeshgar Perampalam , Bock Marina , Chandrasiri Dilanka , Suntharalingam Thadshajini
Published: September 2023

Cold‐formed steel beams are often provided with web holes to accommodate service conduits. These web holes result in reduced structural strength. Accurate estimation of the structural strength, including shear strength, is crucial during the design phase. There are a lot of studies available in the literature investigating the shear strength reduction in cold‐formed steel beams due to web holes. However, the experiments and parametric finite element results were not assessed against Eurocode 3 shear design provisions. Therefore, the shear design of cold‐formed steel beams with web holes is investigated herein. Existing experimental and parametric finite element analysis data on cold‐formed steel beams with circular web holes were collected from the literature. The accuracy of the current Eurocode 3 shear design provisions was then assessed using the collected data. The comparisons showed that the current Eurocode 3 shear design provisions were not suitable to estimate the shear strength of cold‐formed steel beams with web holes. Finally, Eurocode 3 shear design provisions are extended to capture the effect of web holes and verified against the available shear tests and finite element results. It was found that the new extended shear design proposal offers improved accuracy and consistency in shear strength predictions.
Experimental study on earthquake‐induced pounding between steel structures
Authors: Sołtysik Barbara , Jankowski Robert
Published: September 2023

Pounding between adjacent structures has been repeatedly observed during major earthquakes. The phenomenon may cause some local damage at the points of interactions, it may also lead to substantial destruction, permanent deformations or total collapse of colliding structures. The effects of earthquake‐induced structural pounding have been studied for more than three decades now. However, most of the studies concerned masonry as well as reinforced concrete structures and investigations on steel structures are very limited. The aim of the present paper is to show the results of the shaking table experimental investigation focused on earthquake‐induced pounding between three models of steel structures in a row. The models were constructed out of four steel columns made from rectangular box section with additional steel skew bracings so as to prevent transverse and torsional vibrations. To obtain different dynamic characteristics of the models, additional plates were added at the top of each tower. Two configurations were investigated. In the first one, two plates were mounted on the external structures and only one plate at the top of the middle tower. In the second configuration, only one plate was mounted at the top of external towers and two plates on the middle structure. Firstly, the free vibration tests were conducted. Then, the steel towers with different in‐between gap sizes were tested under different earthquakes. The results of the study confirm that interactions between insufficiently separated steel structures may significantly influence the structural behaviour during earthquakes. In most of the cases, pounding has resulted in the increase in the peak responses. In some cases, however, it has played a positive role leading to the decrease in the structural response under seismic excitation. Anyway, even if the response is reduced, interactions should be prevented at the design stage of steel structures since they may result in considerable damage at the points of impacts.
Metrics for the assessment of structural design efficiency applied to steel‐framed industrial buildings
Authors: Ljubinković Filip , Conde Jorge Conde , Gervásio Helena , da Silva Luís Simões
Published: September 2023

Structural efficiency is an important criterion for any sound design. It is, however, an ambiguous and subtle quality, currently lacking a rigorous definition. In this paper, an objective index is introduced, able to measure structural efficiency and quality of design. The index is based on utilization factors calculated in accordance with the Eurocode design expressions. To show the competence of the proposed metrics, a set of realistic cases of steel portal frames is studied in this paper, being a typology that can be fully described with a limited number of parameters, and whose design is highly influenced by instability phenomena, which is specific to steel structures. Finally, a real case study of steel industrial shed that illustrates the application of the Design Efficiency Index is presented and its structural efficiency evaluated.
A review on long‐term behaviour of steel‐concrete composite structures
Authors: Wang Youtian , Khan Mahbub , Li Dongxu , Uy Brian , Thai Huu‐Tai , Ngo Tuan
Published: September 2023

The exceptional structural performance of steel‐concrete composite structures, which harness the advantages of both steel and concrete, has garnered considerable attention. Following a summary of the fundamental time‐dependent characteristics of concrete, this paper reviews the existing studies about the long‐term behaviour of various steel‐concrete composite components, including slabs, beams, columns and walls. For composite slabs, nonuniform shrinkage occurs along the thickness direction. The long‐term behaviour of composite beams is significantly affected by the degree of shear connection. While the creep and shrinkage effects of composite columns are substantially reduced in comparison to reinforced concrete columns, stress redistribution may cause yielding or buckling of the steel tube. However, there is currently limited research available on the long‐term behaviour of composite walls with profiled steel plates, and no studies have been conducted on composite walls made of double‐skinned flat steel faceplates infilled with concrete. This lack of knowledge may lead to design uncertainties for composite coupled wall‐frame structures. To bridge this gap, the authors are currently conducting a corresponding long‐term experimental program.
Assessment of steel‐concrete composite floors dynamic response when subjected to people walking
Authors: Aguiar Jefferson , Ferreira Bárbara , Carvalho Hermes , da Silva José Guilherme Santos
Published: September 2023

This work aims to assess the people‐structure dynamic interaction effect on the steel‐concrete composite floor's structural behaviour, based on of experimental tests and numerical modelling. The investigated structure is associated to a steel‐concrete composite floor building with total area of 1300 m2. In this investigation, biodynamic systems like “spring‐mass‐damper” models with one degree of freedom (SDOF) were used to simulate the people's walking on the floor. The numerical model, developed for the floor building dynamic analysis, adopted the usual mesh refinement techniques present in finite element method (FEM) simulations implemented in the ANSYS software. Based on the experimental results calibration, the floor dynamic response was analysed to study the influence of the people's step frequencies, number of people walking and stationary on the floor, structural damping, and different trajectories of people walking. The floor dynamic response was determined based on the displacement and acceleration values, and compared with those calculated utilising traditional dynamic loading mathematical models. After that, the structural system dynamic response maximum values were compared with the recommended limits proposed in design codes for excessive vibration's assessments to study the human comfort.
Review and outlook about the use of high strength steel in encased composite columns
Authors: Obiala Renata , Anwaar Omer , Yang Jie , Zanon Riccardo
Published: September 2023

The trends of the modern construction are recognized for many years; go large span, go light structures, go sustainable, and keep it simple. In the holistic approach to construction a column remains one of the key structural elements.

This article presents benefits of the application of high strength steel; namely the potential of using S500 and S550 for encased composite columns. The study shows the increase of the buckling capacity and reduction of weight and consequently reduction of the carbon footprint especially when applying XCarb® steel. The results are presented for a single member as well as for an internal column of a 156m high office building.

It is assumed in the analyses that the simplified design method for composite columns defined in EN1994‐1‐1:2004 is applicable to higher steel grades and higher concrete compression classes. Different typologies of the encased steel cross sections are considered: simple H section in rectangular encasement, and cruciform section.