International Journal of Steel Structures最新文献

Non-irradiated and proton-irradiated stainless steel (SS) 304L samples were subjected to corrosion tests in various concentrations of Cl⁻ ions at room temperature. The electrochemical impedance spectroscopy techniques were used to investigate the corrosion behavior, and X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the phase composition and surface morphology. After irradiation, the open circuit potential (OCP) of SS 304L shifted from the passive state to the active dissolution state. It caused the shift of the anodic current peak towards the lower potential, demonstrating the reactivity of the surface and it may increase the corrosion process. The lower semi-circle of impedance for the irradiated SS 304L confirms the localized corrosion process and breakdown of passive films, it enhanced the localized corrosion as indicated by SEM. XRD peak shows a slight shift in the negative direction and formation of Fe₃O₄, for irradiated SS 304L samples. The surface morphology of the irradiated sample consisted of tiny pieces of corrosion product in the surroundings of pits. In contrast, the number and size of pits increased with the concentration of Cl⁻ ions in the solutions. Higher Cl⁻ ions are aggressive towards pitting corrosion for the non-irradiated SS 304L, however, irradiation accelerated the pitting initiation process for SS 304L.

This review presents fresh evidence on the last decade (2010–2021) of research related to numerical modeling techniques that have been employed to comprehend the lateral resistance and buckling behavior of cold-formed steel (CFS) sections when exposed to high temperatures. To attain the principal objective of this study, a systematic literature review (SLR) approach was adopted to address a review question on how numerical modeling has been utilized to investigate the buckling behavior and lateral resistance of CFS sections in elevated temperatures. In addition to the SLR approach, the Preferred Reporting Items for Systematic Reviews and Meta-Analyse (PRISMA) was employed to report all protocols involved in this review work. Based on the review, the impact of fire on the lateral resistance and buckling performance of CFS can be classified according to the type of software, fire curves, numerical models, and design standards. However, the lateral resistance of steel is not a specific attribute that can be measured or evaluated directly from numerical modeling methods. Instead, several structural components and variables can be analyzed as they contribute to the lateral resistance of steel.

A circular hollow section steel damper exhibits equivalent structural performance in an external force direction owing to its circular cross-sectional shape. When a circular hollow section steel damper is placed in a building with stud supports, the stud supporting the damper is connected to the upper and lower beams. When an earthquake occurs, the shear force in the in-plane direction acts on the damper through the stud from the beam. However, depending on the three-dimensional behavior of the building and the arrangement of the damper and surrounding members, a load other than that in the in-plane direction might act on the damper. In this study, the mechanical characteristics of a circular hollow section steel damper in the external force direction were analyzed according to the cyclic load in the circumferential direction using finite element analysis. A reliable finite element analysis model was constructed based on the results of a previous study on unidirectional cyclic loading. The analysis results under cyclic loading conditions in circumferential directional cyclic loading were compared with those under unidirectional cyclic loading. The hysteresis curve resulted in a circular shape under circular directional loading. Moreover, the x- and y-direction load–displacement curves showed a similar strength-increasing ratio to unidirectional loading. Under circumferential directional loading, the strain was concentrated at the end of the welded part, similar to that under unidirectional loading. Furthermore, the strain was distributed in the circumferential directional loading, showing a smaller value than that of unidirectional loading.

As railway traffic volumes and train speeds increase, rail maintenance is becoming more crucial to prevent catastrophic failures. This study aimed to develop an artificial intelligence (AI)-based solution for automatic rail flaw detection using ultrasound sensors to overcome the limitations of traditional inspection methods. Ultrasound sensors are well-suited for identifying structural abnormalities in rails. However, conventional inspection techniques like rail-walking are time-consuming and rely on human expertise, risking detection errors. To address this, a hierarchical classification model was proposed integrating ultrasound B-scan images and machine learning. It involved a two-stage approach—model A for fuzzy classification followed by Model EfficientNet-B7 was identified as the most effective architecture for both models through network comparisons. Experimental results demonstrated the model's ability to accurately detect rail flaws, achieving 88.56% accuracy. It could analyze a single ultrasound image sheet within 0.45 s. An AI-based solution using ultrasound sensors and hierarchical classification shows promise for automated, rapid, and reliable rail flaw detection to support safer railway infrastructure inspection and maintenance activities.

The primary objective of this study is to examine the impact of tubular dampers exhibiting yielding behavior within knee braces and to evaluate diverse parameters affecting the efficacy of steel frames. To this end, six novel types of yielding metal dampers were introduced and subsequently analyzed for their performance within steel frames utilizing finite element analysis facilitated by ABAQUS software. Through static analyses conducted under cyclic loading conditions, the influence of various geometric parameters on the mechanical characteristics and energy absorption capabilities of these dampers was investigated. The findings indicate that modifying the damper geometry can result in alterations of up to 6% in ultimate strength and up to 8% in yield strength. Also, the three-tube mesh model showed the highest yield strength among the different configurations that were studied. The study further shows that the model 3PIPE damper developed the highest bearing force, about 371 kN, while the PIPE-2L model damper showed the least bearing force, which is about 24% of that developed by the model 3PIPE damper.

This study addresses the limitations of traditional bridge health monitoring methods by introducing the representative power spectral density (RPSD) approach, which provides a comprehensive analysis of multifrequency vibrations to detect changes in bridge stiffness under various damage conditions. Motivated by the need for more accurate and sensitive damage detection tools, this study applied RPSD to the Giongong_To bridge in Ho Chi Minh City, Vietnam, to monitor structural degradation over time. Our key findings demonstrate that as bridge damage progresses, vibrational energy shifts from high to lower frequencies, indicating a loss of stiffness. This method improves early detection capabilities, offering economic and safety benefits for bridge maintenance in infrastructure management. The RPSD approach therefore represents a valuable tool for real-time structural health monitoring, especially within extensive bridge networks like those in Vietnam.

The objective of this study was to refine the slip resistance formulas for high-strength bolted joints subjected to combined shear and tension forces. Traditional formulas typically assume that the prying force generated at the contact surface does not contribute to the slip resistance. To explore the influences of the prying force on slip resistance, a trial design was conducted based on the Specifications for Highway Bridges and Recommendation for Design of High Strength Tensile Bolted Connections for Steel Bridges, with variations in parameters such as bolt diameter, bolt pitch, joint flange thickness, and joint flange material. Additionally, numerical analyses were performed to validate the design methodology incorporating prying force. The trial design results demonstrated that the slip capacity improved when the prying force was considered, especially in cases where the external force direction ranged between 27.6 and 90 degrees. The maximum observed improvement in slip capacity was a factor of 1.2. Moreover, the slip resistance of joints with thinner flanges was enhanced when prying force effects were accounted for. This increase in slip capacity due to prying force was further corroborated through fine element method (FEM) simulations. Finally, the findings suggest the potential for enhancing joint compactness and slip resistance.

Upper space limitation problems such as floor slabs and decorative panels on the upper part of steel beams, cause difficulties in the actual strengthening OF steel structures. A new type of retrofitting method for articulated joints of steel frames under the limitation conditions was proposed. The models of articulated joints, rigid joints, and rectangular plate-strengthened joints were established. Finite element analysis was employed to investigate the failure modes, ultimate load-carrying capacity, hysteresis characteristics, ductility, energy dissipation capacity, and stiffness degradation of the joints. Additionally, the parameters of the new strengthened joint models are analyzed. It was found that the hysteresis curves of the strengthening joints were fuller and the bearing capacity and seismic performance were significantly improved, When the length-thickness ratio is less than 20, the bearing and energy dissipation capacities increased with increasing the rectangular strengthening plate size.

The current study intends to evaluate various aspects of GTAW of Austenitic stainless steel AISI 316L. Parametric optimization is one of the project's primary goals. There have been attempts at both single and multi-objective optimization. To achieve the aforementioned goal, an experimental plan is developed. The face-centered central composite design of experiments, based on response surface methods, was employed. After welding, visual inspection, X-ray radiography test, tensile test, and micro-hardness test were performed. The results on ultimate tensile strength, yield strength, and % elongation obtained under various welding circumstances are evaluated. The process has been optimized using response surface methodology.