International Journal of Steel Structures最新文献

This research introduces a novel gusset plate damper designed to safeguard structures from intense seismic activity and enhance the performance of X-braced frames. The damper includes a grooved plate with multiple parallel steel strips, and cross braces segmented into four parts by the central grooved plate. Both sides of each brace segment, a set of strips is embedded within the gusset plate, oriented perpendicular to their corresponding brace axis. The X-braced frames equipped with grooved gusset plate damper (GGPD) were subjected to cyclic loading both experimentally and numerically. The experimental results demonstrated that the proposed system exhibits robust seismic performance. Employing ABAQUS, the calibration results demonstrated excellent agreement between the experimental and numerical outcomes, affirming the accuracy of the finite element method in predicting the cyclic behavior and fracturing patterns of this innovative system. Additionally, the study delved into the local buckling and the necessity of incorporating stiffeners for the grooved plate damper along their edges, evaluating their impact on the main characteristics of the new damper. The findings revealed that when appropriately reinforced at its edges, the proposed damper demonstrates excellent behavior and stable hysteretic curves. Moreover, decreasing the width-to-thickness ratios of steel stiffeners in the GGPD resulted in wider hysteresis loops. Findings indicated that a width-to-thickness ratio of 7 yields favorable outcomes for design parameters, including lateral elastic stiffness and ultimate strength.

Based on the principle of lightweight and easy construction of prefabricated structures, steel octagon-web beam (SOWB) which has the similar appearance of honeycomb was proposed. SOWB with opening web has the advantages of both honeycomb beam and steel structure bridge. In order to obtain reasonable boundary conditions of the finite element (FE) model for evaluating the pure shear buckling capacity of SOWB, the FE method was used to verify the formulas of pure shear buckling coefficient of rectangular thin plate. Based on the FE method and data fitting method, the formulas of pure shear buckling coefficient for octagonal thin plate with round opening were obtained by modifying the parameters of the buckling coefficient formulas for rectangular thin plate. In order to predict the buckling capacity of SOWB, a calculation method was proposed through the strut model. In order to verify the reliability of the proposed method, a buckling analysis model of SOWB was realized by the FE software ABAQUS. The influences of two parameters, such as expansion ratio and the ratio of flange plate thickness to web thickness, on the buckling capacity of SOWB were analyzed. Furthermore, the proposed method which can be used to evaluate the buckling capacity of SOWB was improved by introducing the constraint effect coefficient of the flange.

Spirally welded (SW) columns have found widespread application in diverse structures, including pipeline constructions, wind turbine towers, foundation piles, and high-rise buildings. While prior research has examined cutouts in flat plates, there is a noticeable gap in the investigation of circular columns with similar cutouts. Given the critical role these structures play, it is increasingly imperative to direct research endeavours toward comprehending the behaviour of stress concentration in curved plates featuring cutouts. Specifically, the presence of circular cutouts in a column is shown to induce a diminished stress concentration, owing to the even distribution of stresses. This research delves into a comprehensive study of SW steel columns of different length-to-diameter ratios (L/D) that incorporate circular cutouts of varying sizes and subjected to axial compression. Experiments were conducted on 18 specimens, with results scrutinized and benchmarked against analytical outcomes obtained through Abaqus software. For a comprehensive analysis, 990 finite element (FE) models were created, and non-linear analysis was carried out. Subsequently, a comparative examination was undertaken between longitudinally welded (LW) and SW columns, incorporating varying cutout sizes and positions. The results of both analytical investigations and experimental tests exhibited a remarkably strong correlation. One intriguing and paradoxical observation emerged: an increase in the size of the cutout within an SW column simultaneously enhanced buckling loads while reducing the structural mass. SW columns achieve a more uniform stress distribution along their length due to the presence of a continuous helical weld seam. This helical seam enables the column to efficiently distribute applied loads, minimizing localized stress concentrations. In contrast, LW columns feature weld seams that run parallel to the column's length, potentially creating stress concentrations and vulnerable areas within the structure. Consequently, the continuous nature of the helical weld seam in SW columns enhances load distribution and reduces the likelihood of stress concentration induced weaknesses compared to the linear weld seams in LW columns. This phenomenon underscores the superior load-bearing capacity conferred by the spiral welding technique, positioning SW columns as the preferred choice for applications where strength and efficiency are of paramount importance. Additionally, the data derived from both experimental tests and analytical investigations have been used to propose an equation for the calculation of stress concentration factor around cutouts in SW columns.

A wire is fed into the MIG welding gun, where it sparks and melts to form the weld. It is frequently semi-automated or automatic. TIG welding uses a non-consumable electrode and a separate filler material to combine metals with long rods. TIG and MIG welding are commonly used in industries like pressure vessels, economizers, and Air preheater manufacturing. Combining these processes to optimize benefits and reduce drawbacks is explored. High-thickness welding, found in nuclear reactor core manufacturing, often uses submerged arc welding, but costly. TIG–MIG welding is proposed for 10–40 mm SS316L plates, reducing costs with maintained strength. Design of Experiment is used to vary control parameters. Present article research on SS316L up to 12 mm thick revealed that the following settings would yield the best tensile strength and hardness: 170 A for the welding current, 3 mm for the filler wire diameter, and 14 L/min for the gas flow rate. Values from the experiment and prediction were nearly identical.

This research deals with optimizing the welded I-girder of the single-beam bridge as a variant solution for this type of crane. The mass optimization is achieved by minimization of the welded I-girder cross-section area. The paper takes the following criteria as the constraint functions: strength, local stresses from the trolley wheel pressure, local buckling of the girder plates, global girder stability, deflection, relaxation time and the corresponding design-technological limitations. The hybridization of two new-generation metaheuristic algorithms, the Sine Cosine Algorithm and the Whale Optimization Algorithm, and original algorithms were used for the optimization procedures. The justification for applying these methods in solving practical engineering problems was confirmed by comparing the results with real solutions. As a result, significant material savings were achieved in this research, within the range of 39.52–51.92%. Also, comparing the results indicates the justification and advantages of the proposed hybridization procedure to the mentioned algorithms.

To investigate the seismic performance of a fully assembled framework consisting of prefabricated autoclaved lightweight concrete (ALC) wall panels with partially encased concrete T-shaped columns, a horizontal low-cycle reciprocating load test was conducted on a non-open hole ALC wall panel specimen and an ALC wall panel specimen with a rectangular opening. The influence of the opening on the structure was analyzed, and a comparative discussion is carried out in this article on hysteresis curves and skeleton curves. The experimental results showed that a wall panel opening weakened the overall integrity of the wall, resulting in stress concentration around the door opening and accelerated the damage to the infill wall. In addition, a numerical model was established for analysis, and the finite element results were cross-verified with the experimental results. Based on the experimentally validated numerical model, the influence of different opening parameters on the lateral resistance performance of the framework combination was analyzed, providing theoretical references for engineering construction.

Reinforcement learning (RL) has been used in the development of various control systems presenting desirable control performances. There have been many studies examining the development of structural control algorithms using conventional methods and soft computing algorithms. However, research investigating RL-based structural control techniques in particular is still in an early stage. In RL algorithms, the agent interacts with the environment by taking the appropriate action under the specific state. In the RL-based structural control problem, the environment usually includes the structure, control system, external loads, etc., and it is generally presented by the finite element model. In the present study, the Unity game engine—which has recently come to be used in various engineering simulations because of its accurate physics calculations—was used to construct a reinforcement learning environment for structural control systems. A smart base isolation system (SBIS) that was composed of a magnetorheological damper and four friction pendulum systems was used as an example structural control system, and it was modeled using the Unity physics engine for RL environment. Among various RL algorithms, a Deep Q-Network (DQN) was used to make the control algorithm for the SBIS. The command voltage for the smart base isolation was mapped into the agent’s action. The reward of the DQN algorithm was designed to be a higher value when the agent takes a better action resulting in reduced seismic responses. Three artificial ground motions were used to train the DQN-based control algorithm, and another artificial earthquake was used to investigate the control efficiency of the trained DQN-based control algorithm. The passive-on case with the maximum damper force was used for comparative study. This study shows that the DQN-based algorithm can successfully control the SBIS. The findings show that the unity game engine can accurately present the dynamic responses of the SBIS, showing that it can be effectively used for the construction of a RL environment for structural dynamic systems.

Cold-formed thick-walled steel members have a higher bearing capacity and wider applicability in the mid-rise buildings in comparison with the widely-used cold-formed thin-walled steel framing walls in low-rise buildings. To avoid the shortcomings of cold-forming effect, a structure with hinged or semi-rigid joint steel frame using cold-formed thick-walled steel and cold-formed thin-walled steel framing shear wall is one reasonable choices, and it will be very helpful to simplify the on-site assembling processes. In this paper, a cross-shaped joint with adjustable stiffness was proposed, and better seismic performance was investigated and confirmed by tests. By increasing the thickness of the web plates of the cross-shaped joint, the bearing capacity, stiffness, and ductility of the joint can be significantly improved, and the buckling deformation of the web plate will be reduced. Moreover, a strengthening stiffener, Type 2 proposed in the paper, has a significantly effect on the cross-shaped joint for seismic damage and intact specimens. Using ANSYS software and the SOLID185 element, a finite element model was established. With the increasing thickness of the end plate of the stiffener Type 2, both the stiffness and bearing capacity of the cross-shaped joint can be significantly increased.