Steel Structures Research Articles

Data quality-oriented scan planning for steel structure scenes using a probabilistic genetic algorithm

Scan planning is often challenging particularly in steel structure scenes because of its complex shapes and occlusions. Meeting the requirements of data quality for the scan-to-BIM model is also another issue for accurate point cloud data acquisition. To address these issues, this study proposes a solution that determines an optimal number of scans and corresponding scan positions and parameters. Three primary steps include 1) extraction of feature points using a slicing cutting method and range images, 2) evaluation of data quality using visibility check and data density evaluation, and 3) determination of optimal scan configuration using a probabilistic genetic algorithm. In order to validate the proposed solution, a series of lab-scale experiments involving five case studies with different scenarios are conducted and the results show a similarity of 88.4% between simulation and actual experiments, demonstrating the feasibility of the proposed method for steel structure scenes with complex shapes and occlusions.

"Exploring the role of lithium in Al2O3 tritium permeation barrier development: A crucial challenge for fusion reactor progress"

The development and application of robust tritium permeation barriers (TPBs) are crucial for a safe and economical fusion reactor operation because tritium permeation could cause serious safety problems, such as the brittleness of the structural material, fuel loss, and radioactive contamination. Coatings may effectively inhibit the permeation through the structural materials of tritium fuel generated inside the breeding blanket (BB) reducing the loss of lithium inventory contamination of the ancillary systems and the exposure of workers and the population. Al2O3 has been preliminary selected as the EU candidate for tritium permeation reduction of structural steels in the Water-cooled lithium–lead breeding blank (WCLL) concept, because of its very high permeation reduced factor (PRF). However, because of the chemical reactivity of lithium, several authors report the formation of Lithium aluminates after exposure to PbLi baths, based on different experimental techniques. In this contribution, we will show recent results about the quantification of the extent of the reaction and the thickness of the reacted layer and discuss the possible effects, that may happen under neutron irradiation based on the species produced (T and He) in the nuclear reactions (n, T) and (n, α) with 6Li and 7Li, with the Li atoms in the reacted layer To do that, the atomic density of produced T and He per second out of the transmutation reaction and the He/T ratio are calculated for diverse Li contents. Subsequently, we implant He into the coatings and characterize the desorption rate and the morphology. Finally, discussion and recommendations for further coating development will be presented.

Seismic Performance of Industrial Buildings During the 2023 Kahramanmaras, Turkey Earthquakes

ABSTRACT This study investigates the structural performance of industrial buildings following the February 6, 2023, earthquakes in Kahramanmaras, Turkey, focusing mainly on industrial zones. Causes of damage and damage levels were evaluated for 389 industrial structures, including precast concrete and steel structures. This research demonstrates the need for improved construction practices, advanced seismic design, and quality control. Commonly observed structural damage is highlighted. Identifying the critical common structural damage types is essential to developing effective mitigation strategies and enhancing earthquake resilience. It is concluded that advanced seismic design practices can significantly improve the overall structural performance, resilience, and functional recovery.

The Effect of Expanded Vermiculite on the Fire Resistance of Waterborne Acrylic Coatings.

Due to their ability to prevent or slow the spread of fires, fire-retardant coatings are utilized as the main means of fire protection for steel structures, combining easy application and high economic efficiency. This study investigates the effects of the particle size and dosage of expanded vermiculite (EV) on the fire resistance and application performance of coatings. Ammonium polyphosphate, melamine, and pentaerythritol were used as intumescent fire-retardant systems, along with waterborne hydroxyl-modified acrylic resins as the film-forming substances. The properties of fire resistance coatings were tested via scanning electron microscope (SEM), X-ray diffractometry (XRD), thermogravimetric analysis (TGA), limiting oxygen index (LOI), and cone calorimetry. The excellent fire performance of the coatings with 3 wt.% 300-mesh EV was proven, exhibiting a relative expansion of 30.43 times. Moreover, the surface structure of the charcoal layer was dense. The total smoke production (TSP) and smoke concentration (TSR) were only 0.18 m2 and 0.25 m2/m2.

Study on Vibration and Noise of Railway Steel–Concrete Composite Box Girder Bridge Considering Vehicle–Bridge Coupling Effect

A steel–concrete composite beam bridge fully exploits the mechanical advantages of the concrete structure and steel structure, and has the advantages of a fast construction speed and large stiffness. It is of certain research value to explore the application of this bridge type in the field of railway bridges. However, with the rapid development of domestic high-speed railway construction, the problem of vibration and noise radiation of high-speed railway bridges caused by train loads is becoming more and more serious. A steel–concrete composite beam bridge combines the tensile characteristics of steel and the compressive characteristics of concrete perfectly. At the same time, it also has the characteristics of a steel bridge and concrete bridge in terms of vibration and noise radiation. This feature makes the study of the vibration and noise of the bridge type more complicated. Therefore, in this paper, the characteristics of vibration and noise radiation of a high-speed railway steel–concrete composite box girder bridge are studied in detail from two aspects: the theoretical basis and a numerical simulation. The main results obtained are as follows: Relying on the idea of vehicle–rail–bridge coupling dynamics, a structural dynamics analysis model of a steel–concrete combined girder bridge for a high-speed railroad was established, and numerical program simulation of the vibration of the vehicle–rail–bridge coupling system was carried out based on the parametric design language of ANSYS 18.0 and the language of MATLAB R2021a, and the structural vibration results were analyzed in both the time domain and frequency domain. By using different time-step loading for the vehicle–rail–bridge coupling vibration analysis, the computational efficiency can be effectively improved under the condition of guaranteeing the accuracy of the result analysis within 100 Hz. Based on the power flow equilibrium equation, a statistical energy method of calculating the high-frequency noise radiation is theoretically derived. Based on the theoretical basis of the statistical energy method, the high-frequency noise in the structure is numerically simulated in the VAONE 2021 software, and the average contribution of the concrete roof plate to the three acoustic field points constructed in this paper is as high as 50%, which is of great significance in the study of noise reduction in steel–concrete composite girders.

One-Step Spraying Strategy for Fabricating Bioinspired, Graphene-Based, and Multifunctional-Integrated Coatings on Structural Steel with Good Water Repellency, Fireproofing, Anticorrosion, and Durability.

Traditionally, many coatings were merely concentrated on settling the inherent fire protection problem of steel structures, while surface contamination and corrosion susceptibility should also be considered. Concurrently addressing these problems in fireproof efficiency and surface multifunctionality has become an issue of great significance in further expanding the application value in industrial and daily scenarios. Based on this condition, ecofriendly, graphene-based, and superhydrophobic coatings with multifunctional integration were constructed on steel via a one-step spraying method. The as-prepared coatings mainly consist of epoxy resin (EP), silicone resin (SR), a cyclodextrin-based flame retardant (MCDPM), expandable graphite (EG), and multilayered graphene (MG). The results demonstrate that the water contact angle (WCA) and water sliding angle (WSA) of as-prepared coatings can reach 156.8 ± 1.6 and 5.8 ± 0.7°, respectively, revealing good water repellency and self-cleaning properties. The coatings can also exhibit adequate adaptability for various substrates including wood, polyurethane foam, and cotton fabrics. Besides, good durability and robustness of coatings have been also verified via acid/alkali immersion, outdoor exposure, O2/plasma etching, and linear abrasion tests. Simultaneously, the coatings can exhibit excellent anticorrosion capacity for steel materials via a double barrier effect. Most importantly, the coatings have exhibited the lowest backside temperature (234.5 °C) during fire impact tests, suggesting excellent fireproof and heat insulation performance. This fact can be ascribed to the conjunct action between the physical/chemical charring process of flame retardants and the remarkable thermal stability of graphene. Consequently, this article can be expected to further promote the development and application of multifunctional-integrated coatings for steel structures in more fields.

Economical and technical analysis of steel and reinforced concrete structures in high standart small buildings

This paper aims to analyse the technical and economic feasibility of a high-standart residence construction using steel structures. The advantages of steel structures, including durability, strength, quick construction, architectural versatility, environmental sustainability, low maintenance, and property value appreciation, are analysed. The study takes account of high standards in construction materials and international Codes. After choosing steel structures, a comparison with reinforced concrete is made. Cost analysis, construction time evaluation, and the development of a project timeline are also analysed.

Assessment of structural materials containing notch-type defects: A comprehensive validation of the FAD-TCD methodology on metallic and non-metallic materials

This paper provides a comprehensive description, and the subsequent validation, of a structural integrity assessment methodology of structural materials containing notch-type defects. The approach is based on the combination of Failure Assessment Diagrams (FAD) and the Theory of Critical Distances (TCD). The former provides the general assessment tool, which is exactly the same one as that used for crack-like defects, whereas the latter provides the notch effect correction required for the analysis of this type of defects. Finally, the proposed methodology is validated on a number of metallic and non-metallic structural materials, with 1,106 experimental results on different types of testing specimens, covering four structural steels, aluminium alloys 7075-T651 and 6060-T66, PVC, PMMA, PA6, fibre-reinforced PA6, 3D printed (Fused Filament Fabrication) ABS, PLA and graphene reinforced PLA, granite and limestone. The results show how the FAD-TCD methodology provides safe reasonably conservative assessments on the mentioned structural materials in the presence of notch-type defects.

Experiment and design of cold-formed steel equal-leg lipped angle under axial compression

To study the buckling behavior and the design method of the load-carrying capacity of cold-formed thin-walled lipped angle, axial compression tests were carried out on 32 lipped angle columns with different sections and slenderness ratios which were manufactured with high strength zinc-coated grades G450 structural steel sheets. The experimental results showed that the long column with a small width-to-thickness ratio displayed global flexural-torsional buckling, local buckling was found for the short column with a large width-to-thickness ratio. Other specimens demonstrated interactive buckling with local buckling and flexural-torsional buckling. The specimens with torsional buckling all showed post-torsional buckling strength. Then ABAQUS finite element software was used to simulate the lipped angle specimens. The simulation results were in good agreement with the test results about buckling modes and ultimate strength which indicated that the established finite element analysis model was reasonable and feasible. Therefore, the influences of the slenderness ratio, width-thickness ratio, and width ratio of the leg to lip on the ultimate strength of cold-formed thin-walled lipped angle were analyzed using finite element software. The analysis showed that the ultimate capacity of the angle decreased greatly with the increase of the slenderness ratio. The ultimate capacity increased in the range of width-to-thickness ratios of 15–30 when the angles had the same lengths. The increasing of the width of the lips increased the ultimate capacity, but the increase of the ultimate capacity of the angles would lower when local buckling occurred at the lips. Finally, based on the test results, the modified effective width method and direct strength method were proposed to calculate the capacity of the cold-formed thin-walled lipped angle under axial compression. The comparison between the predicted results with the test and finite element analysis showed that the proposed methods were accurate and feasible.

Impact of Jet Fires on Steel Structures: Application of Passive Fire Protection Materials

Jet fires are the second most common fire scenario after spill fires. This type of fire is characteristic of gas and gas–oil fires occurring on oil platforms and gas production and processing plants. The consequences of such fires are characterized by high material damage; this is associated with extensive networks of technological communications, since there is a high density of technological facilities and installations in the territory where these fires occur. At such facilities, there is a large number of steel structures, which under the action of high temperature quickly lose their strength and deform. To protect steel structures in the oil and gas industry, fire protection is used, which consists of different types: boards in the form of flat plates, plasters, and epoxy paints. This paper compares three types of fire protection materials for steel structures under jet fire: board fireproofing, plaster composition, and epoxy coating. When comparing the efficiency in jet fire, cement boards were found to be the best. However, despite the better fire protection efficiency, their low application is expected due to their massiveness and the high cost of such protection and the difficulty of installation. Nevertheless, the development of fire depends on the place of its origin, the size of the initial fire zone, and the stability and massiveness of the metal elements of the vessel structure or the structure of the boards on which the equipment can be placed. Therefore, it is necessary to take these factors into account when selecting fire protection and to apply it depending on the required fire resistance limits of structures, which should be determined depending on the fire development scenarios.

Determination Of Weld Thickness In Hollow Section Connection Under Local Buckling Effect

Hollow section profiles are widely used in the structural steel industry. An important point to take into consideration in such connections is the continuous transfer of internal forces from element to element. One of the measures taken to ensure this continuity is to use end plates. The connection between plates and elements is mainly provided by welds. The aim of this study is to determine an optimum weld thickness for connections subjected to local buckling of box-beam-columns under bending. Corner and circular fillet welds were used to join the designed plates with box columns and beams. Hollow section profile connections were experimentally studied in the Steel Structure Laboratory of the Department of Civil Engineering of Süleyman Demirel University. Results were used to develop numerical models. Ansys Workbench was used in numerical models to analyze the corner welds of different thicknesses and lengths depending on plate dimensions and to examine their behavior.

Flexural Behavior of Galvanized Iron Based Cold-Formed Steel Back-to-Back Built-Up Beams at Elevated Temperatures

Cold-formed steel (CFS) sections have become popular in construction due to several advantages over structural steel. However, research on the performance of galvanized iron (GI)-based CFS under high temperatures, especially regarding its flexural behavior, has been limited. This study extensively investigates how GI-based CFS beams with varying spans behave under elevated temperatures and subsequent cooling using air and water. This study examines the impact of temperature loading and compares the effectiveness of air- and water-cooling methods. Experimental results are validated and analyzed alongside findings from finite element modeling (FEM) using ABAQUS (2019_09_13-23.19.31) and the Direct Strength Method (DSM). Additionally, this study conducts a parametric investigation to assess how beam span influences flexural capacity. Among beams heated to the same temperature, those cooled with water show slightly lower load capacities compared to those cooled with air. The highest load capacity observed is 64.3 kN for the reference specimen, while the lowest is 26.2 kN for the specimen heated for 90 min and cooled with water, a 59.27% difference between them. Stiffness decreases as heating duration increases, with the reference section exhibiting significantly higher stiffness compared to the section heated for 90 min and cooled with water, with a 92.76% difference in stiffness. As heating duration increases, ductility also increases. Various failure modes are observed based on different heating and cooling conditions across different beam spans. This study provides insights into how GI-based CFS beams perform under temperature stress and different cooling scenarios, contributing valuable data for structural design and safety considerations in construction.

Superior thermal response of additive manufactured porous stainless steel with carbon nanotubes

The temperature rise in the battery cells during continuous operation leads to a thermal runaway that affects the life and performance of electric vehicles. For such reasons, heat sinks with high thermal conductivity will be of utmost importance in maintaining optimal operating temperatures. This paper presents the development of a 3D-printed SS 316L porous structure with carbon nanotubes coated on it through a chemical vapour deposition method to enhance thermal management. The carbon nanotubes (CNTs)-coated porous Stainless Steel (SS) structure showed enhanced thermal performance. It absorbed heat 7 % faster than the non-coated and dissipated heat 138 % more at a heat input of 36.5 W. For the fixed 120-second time, a temperature difference existed of 3.9 °C during heating and up to 4.4 °C during cooling. These results demonstrate that the CNT coating dramatically improves the thermal response of the porous SS structure. This original approach for integrating CNT coatings with 3D-printed porous SS structures opens up a potential avenue for the efficient design and manufacturing of a heat sink, thus increasing the reliability and durability of the battery systems in electric vehicles.

An experimental and numerical analysis of slit plate as replaceable fuse in moment resisting frame

This study contributes to the ongoing progress in developing cost-effective structural fuse solutions for steel structures, emphasizing enhanced strength, ductility, and energy dissipation capacity. These fuses are strategically placed to coincide with plastic hinge locations under lateral load. During minor seismic events, they provide substantial rotational stiffness, while during medium to large earthquakes, they leverage their post-yield strength for effective energy dissipation. Three varieties of beam-column sub-assemblages viz. single oval slit damper fuse (SOSDF), dual oval slit damper fuse (DOSDF) and single elliptical slit damper fuse (SESDF), featuring advanced replaceable fuses were evaluated using both experimental and numerical analyses under quasi-static loading conditions. The seismic performance of these specimens was comprehensively assessed, focusing on characteristics such as moment-carrying capacity concerning rotation, energy dissipation, ductility, and failure modes. The findings indicate that all specimens exhibited stable hysteresis, with connections utilizing SESDF and DOSDF showing slightly higher moment carrying capacities (19 % and 10 %, respectively) compared to those employing SOSDF. According to AISC 2016 standards, all three connections were classified as full-strength connections. Moreover, the ductility of specimens incorporating SESDF was notably higher as 3.5, marking a 28 % and 26 % increase over the ductility of SOSDF and DOSDF connections, respectively. In major seismic events, damage was confined solely to the fuse components, with no damage observed in the beam and column. Detailed finite element analysis using ABAQUS CAE further corroborated these findings, demonstrating good alignment between experimental and simulated results.

Examining Shape Dependence on Small Mild Steel Specimens during Heating Processes.

With regard to the heating technology of small test specimens (D < 1 inch, i.e., 25.4 mm), only a limited amount of data and literature are available for making adequate technological decisions. Heating time of small geometric shapes is influenced by the technological parameters of the furnace, the temperature, the disposition technique in the furnace and the geometric characteristics of the workpiece. How to shorten heating time to achieve a suitable material structure is a vital question, while considerable energy is saved at the same time. Among the geometric characteristics, shape dependence is one of the important aspects that must be taken into account in terms of heating technology. Shape dependence is usually taken into account with empirically produced correction factors, which can result in significant oversizing of heating time, energy-wasting technology and material structure of insufficient fineness. In the course of our work, we investigated and compared the shape dependence of cylindrical and prismatic specimens with the same surface-to-volume ratios, which were combined with surface heat transfer analyses and geometric effect tests to formulate new approximate equations for determining heating time. As a result, we could mathematically derive a relationship between heating time, size and shape of the active surfaces, the correlation of which can shorten heating time by 20%. In addition, a shape factor (1.125) between cylinder and prismatic-shaped specimens was determined, which can be used with the new equation to calculate heating time for similar specimens. At last, a relationship is developed between the amount of heat that can be stored in the body during heat equalization and the complexity of the shape, which can be characterized through ratios depending on heating times and active surfaces in the function of total surface/volume ratio. Based on this relationship it can be determined more precisely when heat equalization occurs; therefore, shorter heating time can be achieved. In conclusion, with the help of this new method, optimal heating time for structural steel components, in the case of small cross-section and weight, can be determined.

Uniaxial material model with softening for simulating the cyclic behavior of steel tubes in concrete‐filled steel tube beam‐columns

AbstractThis paper presents a new uniaxial constitutive material formulation with softening for simulating the inelastic behavior of steel rectangular tubes in concrete‐filled steel tube (CFST) members. The primary behavioral characteristics of the steel tube in CFST members are isolated and pronounced through a carefully designed experimental campaign with CFST specimens subjected to uniaxial strain‐based loading protocols. The model is expressed in an effective stress–strain domain, where the effective uniaxial strain is defined as the uniaxial displacement within a dissipative zone over a predefined length. In the pre‐peak state, the proposed model can effectively capture the combined kinematic/isotropic hardening and Bauschinger effect—characteristic of mild structural steels—within the framework of rate‐independent plasticity. In the post‐peak state, the proposed model traces strength deterioration due to outward local buckling, which is a characteristic nonlinear geometric instability in CFST members due to the presence of the filled concrete in the steel tube. The proposed constitutive formulation incorporates a softening branch that exponentially decays to trace the stabilization of the outward buckling wave within the buckling region in successive inelastic loading cycles. Cyclic deterioration of the effective stress is explicitly considered via an energy‐based rule. The proposed model is calibrated to a CFST dataset. Regression equations are proposed for predicting the input model parameters. These equations cover a wide range of geometric parameters and structural steel materials in CFST members. Comparisons with prior tests on actual CFST beam‐columns under planar symmetric cyclic loading suggest that conventional 2‐dimensional displacement‐based beam‐column elements can predict the full‐range of the hysteretic behavior of the CFST members with the proposed constitutive formulation including cases where the post‐peak response of CFST members exhibits negative stiffness.

Exploring anti-corrosion properties and rheological behaviour of tannic acid and epoxidized soybean oil-based fully bio-based epoxy thermoset resins

This research explores the physicochemical attributes of a fully bio-epoxy thermoset aimed at serving as an anti-corrosion coating for safeguarding carbon steel structures in marine environments. Throughout this investigation, various epoxy thermosets formulations, based on epoxidized soybean oil (ESO) and tannic acid (TA), were synthesized by adjusting the initial ratios of epoxide:hydroxyl groups (epoxy:OH). These formulations were subsequently applied onto carbon steel substrates and subjected to thermal curing at moderate temperatures (170 °C) to evaluate their anti-corrosion effectiveness using electrochemical impedance spectroscopy (EIS). The examination of the total impedance values derived from EIS Bode diagrams (>106 Ω) revealed a notable anti-corrosion efficacy that endured over several months of immersion in 3.5 wt% NaCl solutions. In addition to electrochemical assessment, a rheological analysis was conducted to determine the optimal curing temperature for each formulation and to track the evolution of their mechanical properties throughout the curing process. Furthermore, the progression of corrosion at the coating-metal interphase was quantified using samples featuring artificially created notches to facilitate rapid water penetration, reaching the protected surface. Moreover, cross-cut and pull-off adhesion tests were conducted on coatings cured with various epoxide:hydroxyl ratios, yielding exceptional results on carbon steel substrates. Overall, a great potential for anti-corrosion protection has been demonstrated on the developed fully bio-based coatings with tuneable mechanical properties, regarding the initial component ratio, to reach the specific requirements for specific applications.

Post-fire structural material behaviour of high- and ultra-high-strength steels – Experimental study and aids for assessment for further use and potential reuse after fires

A thorough understanding and realistic modelling of the essential post-fire material behaviour is crucial for a safe assessment of the residual structural performance of steel components and the reliable further usage of steel structures after fires. This paper presents a comprehensive experimental study of the constitutive material behaviour after heating-cooling cycles of two quenched and tempered high-strength steels (S690QL, S960QL) as well as two thermomechanically rolled steels (S960M, S1100M). The results are compared to both the behaviour of grade S355J2+N mild steels and a comprehensive database of existing post-fire tests. Except for high- and ultra-high-strength steels, which are exposed to very high temperatures above the A1-phase-transformation-temperature during fires, the assumption of reversibility of the mechanical properties for structural designs of steel structures has been confirmed. At high and very high steel temperatures, the microstructure changes and the strength properties after fire are significantly lower than those of virgin high-strength steel specimens. The study thus provides the basis for reliable structural designs and future normative guidance of the post-fire structural steel designs.

Performance of laser metal deposition on hot-rolled stainless steel for hybrid steel structures

The construction sector is increasingly recognising the potential of metal additive manufacturing (AM) for fabricating complex steel details with enhanced performance and reduced resource usage. In the coming years, the application of AM technologies is expected to advance, leading to the development of new structural elements and improved performance of existing ones. This progression involves the integration of conventional construction steel with AM techniques, such as laser metal deposition (LMD), to create hybrid systems that incorporate efficient details. LMD offers the advantage of overcoming size limitations associated with laser powder bed fusion (LPBF) while leveraging its geometric capabilities. In this study, the mechanical behavior of hybrid steel components, fabricated using LMD on AISI316L stainless steel plates, was investigated through an extensive experimental campaign involving 40 samples. Axial tests, fatigue tests, and material characterisation were conducted to evaluate strength criteria and long-term behavior. Results demonstrate that LMD-produced AISI316L exhibits mechanical properties compliant with EN1993's "Design of steel structures" encompassing elastic and plastic behavior. Furthermore, both LMD samples and hybrid specimens exhibit promising fatigue performance, aligning with the highest fatigue detail category (detail category 160) for conventional steel details.

Metaheuristic algorithm inspired by enterprise development for global optimization and structural engineering problems with frequency constraints

In this study, a novel metaheuristic optimization algorithm inspired by the enterprise development (ED) process was developed. This process encompasses tasks, structure, technology, and human interactions. A mechanism for switching activities was utilized to determine each step by updating the searched solutions. The ED optimizer underwent evaluation against 50 mathematical functions and 54 IEEE Congress on Evolutionary Computation (CEC) functions, and it was compared with six up-to-date algorithms, three winners of CEC 2020 in real-world single-objective constrained optimization, and ten well-known algorithms. The evaluation results revealed that the ED optimizer outperformed the algorithms in mathematical tests. Using finite element simulation, this novel method was applied to minimize steel structure component weights under various frequency constraints. The engineering designs included a 37-bar planar truss, a 52-bar dome, a 72-bar space truss, a 600-bar dome, and a 1,410-bar dome. Optimization results for these structures showed that the developed ED optimizer yielded the optimal solution and required fewer function evaluations. In conclusion, the ED optimizer is a superior metaheuristic algorithm that can effectively solve complex structural design problems.