International Journal of Steel Structures最新文献

The Park-Ang damage model is widely used in evaluating structural damage status, but the interactions between compression and biaxial drift still need to be determined. This study takes 42 steel columns, of which sections are H-shaped and box-shaped, as research objects, load conditions of one-directional drift, biaxial drift, and combinations of compression and drift have been analyzed. An equivalent damage index D_eq, which is the sum of the 0.42 power of drift damage in two perpendicular directions, is proposed based on the Park-Ang model. And the denominator coefficient α and its calculation equations are proposed to consider the global second-order effect. Furthermore, a 5-story steel frame is taken as a case study, and the damage index marks the failure time of the middle column in each story according to this method.

Bolt lap joints are the most common types of connections in transmission towers structures. In the paper, experimentally validated finite element method models of angle profile connected with one bolt are presented. Several issues were addressed in these models including non-linear material parameters, convergence of the analysis, and the influence of the thread on the bolt. Three different model types were compared with the experimental load–displacement diagrams. The most advanced model showed good correlation especially in the elastic portion of load transfer by the bolt bearing due to consideration of a thread on a bolt. A subsequent parametric analysis of the model showed that friction coefficients, bolt prestressing force and ultimate tensile stress of the material play an important role in these connections. Lastly, the results of the load carrying capacity of the joint from the analysis were compared with the results from the formulas from the Eurocode 3 and EN 50341-1 standards. The numerical model supports the Eurocode 3 approach in which net cross-section fracture depends on the location of the bolt. The conclusion drawn from this work can be used for reliable finite element modeling of bolted joints.

This paper proposes a standardized data- and model-driven digital engineering framework for steel girders based on an information delivery schema. The proposed framework digitizes designer-defined geometric information. It ensures seamless integration across project phases by linking quantity takeoff at the design stage to the automatic generation of shop drawings for fabrication. Furthermore, it supports a model-driven part comparison system and enables digital pre-assembly through the use of an updated digital model throughout the life cycle. Through the model-driven integration of design, manufacturing, and assembly, rapid digital transformation is achieved by automating processes that are traditionally performed manually in steel girder projects. This benefit becomes particularly evident when frequent design changes occur or when the framework is applied to similar projects. The effectiveness of the proposed methodology is demonstrated through a comparative evaluation with conventional practices based on three bridge projects scheduled for construction. The results indicate that the proposed approach provides a more efficient and systematic workflow. By employing the information delivery system, designers can accumulate and reuse life-cycle data to continuously refine future designs. This ultimately establishes a data-driven environment that supports design for manufacturing and assembly.

Welding defects in steel structures are difficult to control, leading to fatigue cracking of the weld. This study develops an improved AlexNet model for welding defect detection and classification of steel structures. An experimental study on welding defect detection in steel plates was conducted. An optimal image preprocessing method for steel welds was proposed. And the effectiveness of this method is proved by comparative experiments. Steel structural components were produced including six types of weld defects. Based on the characteristics of weld defects in steel structures, the framework of the network model was optimized and an improved AlexNet network model was constructed. The numerical results show that the convergence accuracy of the improved AlexNet model reaches 98%, while the respective convergence accuracies of conventional AlexNet and GoogLeNet are 90.0% and 94.0%, respectively. Moreover, the improved AlexNet model has better performance in terms of training speed and prediction accuracy.

Metallic dampers are critical components in structural engineering for seismic energy dissipation. This study investigates the performance of bolted metal dampers, specifically focusing on the influence of additional nuts placed in the free zone of the bolts. While conventional dampers often face premature buckling issues in diagonal steel cross members (SCM), the proposed configuration aims to mitigate this by enhancing lateral stability. Experimental tests were conducted on various damper configurations to evaluate their load-carrying capacity, energy dissipation, and failure modes. It is the location and number of nuts used in their free zones as a parameter in the five types of bolted metallic dampers used in the experiments. The results demonstrate that the strategic arrangement of nuts in the free region significantly prevents bolt buckling, leading to a substantial increase in energy absorption and structural resilience. Specifically, the implementation of nuts improved the seismic the lateral load carrying performance by about %30 compared to standard bolted dampers. This research provides a cost-effective and practical solution for improving the seismic safety of steel beam-column joints.

An extensive experimental and numerical analysis was conducted to examine the axial compressive behavior of circular concrete-filled steel tube (CFST) columns. A total of 24 specimens with varying geometrical and material parametersincluding three heights (L), three diameters (D), two wall thicknesses (t), and two concrete strength (f_c) classes were tested to assess the effects of slenderness (L/D), sectional slenderness (D/t), and strength index (SI) on the ultimate load capacity of CFST columns. The experimental results indicated that increasing concrete strength enhances the ultimate load capacity, whereas higher L/D ratios lead to pronounced strength reduction. Finite element (FE) models developed in ANSYS were validated against the test data and exhibited excellent agreement, with FE predictions slightly exceeding experimental values. The axial capacities were also evaluated according to AISC 360-16 and Eurocode-4 provisions, with Eurocode-4 yielding closer predictions to the experimental findings. In addition, Strength Index-Slenderness (SI-L/D) plots have been created to estimate the ultimate load-carrying capacities of CFST columns. A practical approach has been proposed using these plots. This approach has demonstrated a robust correlation with the design standards for the evaluation of CFST columns.

Joint stiffness is a critical factor influencing the stability of a reticulated shell. This study introduces an improved POLO-1 joint with excellent mechanical performance, developed based on the original POLO-1 joint, and systematically examines its bending performance under pure bending loads. Numerical simulations of 18 finite element models confirm that the novel gear bolt joint significantly outperforms the original gear bolt joint in bending performance. According to the structural similarities between the original POLO-1 joint and the original gear bolt joint, the improved POLO-1 joint is proposed. Further, using 58 finite element models and considering variations in plate thickness, bolt radii, and two distinct loading schemes, a comparative analysis of the bending performance of the original and improved POLO-1 joints is conducted. The findings are as follows: (I) Under strong-axis bending moments, varying plate thicknesses result in an 18%–30% increase in initial stiffness and a 30%–65% improvement in ultimate bending moment for the improved POLO-1 joint. (II) Under weak-axis bending moments, the improved POLO-1 joint displays a more pronounced enhancement, with initial stiffness increasing by 150%–220% and ultimate bending moment improving by 110%–250% with different plate thicknesses. (III) Under strong-axis bending moments, variations in bolt radii reveal that the improved POLO-1 joint exhibits superior bending performance compared with the original POLO-1 joint. (IV) Under weak-axis bending moments, considering bolt radii, the improved POLO-1 joint achieves a 150%–225% increase in initial stiffness and a 110%–245% improvement in ultimate bending moment. (V) The performance enhancement of the improved POLO-1 joint, when considering plate thicknesses or bolt radii, is primarily due to the evident extension of the plate’s yielding area, enabling better utilization of material properties and a notable improvement in bending performance.

Despite its impressive structural features, the fatigue behavior of orthotropic steel deck (OSD) is a major concern under the effect of repeated traffic loading. This study aims to propose machine learning (ML) based predictive models for fatigue life prediction of rib-to-floorbeam welded connection (RF-WC) in OSD strengthened by ultra-high reinforced concrete (UHPC). The fatigue crack propagation of RF-WC was first studied using ABAQUS/FRANC3D crack simulation technology to create the dataset for the fatigue life prediction. Three ML-based predictive models were established, including one conventional ML model (SVR model) and two deep learning (DL) models (DNN and LSTM models) for fatigue life prediction of RF-WC. Numerical analysis results indicated that the crack growth rate increased significantly as the stress range and the size of the initial crack increased. On the contrary, a thicker UHPC layer remarkably slows down the crack growth rate. Results showed a strong agreement between the predicted fatigue life using the ML-based predictive models and the numerical analysis results. Additionally, the predicted fatigue life closely aligns with the test results, which further emphasizes the efficiency and high accuracy of the proposed models for fatigue life prediction of RF-WC. It is noticed that, among the proposed ML-based models, the LSTM model demonstrated the highest accuracy for the fatigue life prediction of RF-WC.

This study investigates the dynamic consequences of rigid plastic structures under high loads, such as blasts, car crashes, and gas explosions, in which the applied load is brief but several times more than the static collapse load. Structures were traditionally intended to handle static loads of set magnitudes throughout time; however, it is now understood that structures must survive both dynamic and static loading. Frames, which are extensively utilized in civil engineering applications such as foundation building, infrastructure development, and aeronautical engineering, bear a variety of loads. As a result, a trustworthy approach for analyzing dynamic behavior needed to be devised, which would enhance engineering practice. This study uses mathematical programming approaches, notably the Linear Complementary Problem (LCP) solved using the Lemke algorithm, to address concerns with rigid-plastic constructions under dynamic stresses. The study focuses on the dynamic rigid plastic response of frame structures using computational modeling confirmed by finite element analysis (ABAQUS) and experimental testing (pendulum mass technique). LCP results closely match experimental and numerical data, with peak displacement responses of 20.77 mm (experimental), 19.3 mm (Lemke), and 20.3 mm (FEM). Overall, the LCP formulation offers a systematic and effective mathematical method for capturing and solving the rigid-plastic response of skeletal systems under short-duration, high-intensity loading.

The present work examines the seismic behaviour of Special Truss Moment Frames (STMFs) strengthened with fluid viscous dampers (FVDs) installed in the designated special segments. The frame models were conceived and proportioned following the requirements of the AISC Seismic Provisions for Structural Steel Buildings. The research focuses on three distinct fluid viscous damper (FVD) configurations: diagonal, X, and toggle, which were assessed through a comprehensive numerical study guided by FEMA P695 guidelines. Nonlinear static (pushover), nonlinear time-history, and incremental dynamic analyses (IDA) were carried out using SeismoStruct to establish capacity curves, collapse fragility curves, and key performance indicators such as the collapse margin ratio (CMR) and its spectral-shape-adjusted counterpart. Results indicate that each retrofit configuration significantly enhances the seismic load-resisting capacity, confines inelastic response to the intended special segment, and reduces the likelihood of collapse compared to the unretrofitted frame. These findings validate the feasibility of using fluid viscous dampers to enhance STMF seismic performance, providing a practical and minimally invasive strategy to achieve life safety performance targets under increased spectral demands.