Numerous confinement techniques have been proposed to enhance the strength and ductility of circular concrete-filled steel tube (CFST) columns. This study introduces an innovative confinement method for short circular CFST columns incorporating internal spiral plate stiffeners. The rectangular spiral plates are attached to the inner surface of the steel tube such that their flat faces remain in direct contact with the tube wall. This configuration minimizes obstruction to concrete flow and ensures proper compaction without void formation during casting. The spiral plates were connected to the steel tube using intermittent external fillet welding and tested under axial compression to evaluate their influence on load-carrying capacity and deformation behavior. A detailed finite element (FE) model was developed to complement the experimental program and to investigate the effects of key parameters, including spiral pitch, plate width, and weld spacing, on axial performance. The results demonstrate that incorporating spiral plate stiffeners increases the ultimate strength by an average of 16% compared to conventional CFST columns. Strength enhancement ranged from 5% to 55% as the spiral pitch decreased from 150 mm to 25 mm, while reducing weld spacing from 180° to 30° improved strength by 6–10%. A normalized spiral pitch (p/D) ≤ 0.5 provided effective confinement, resulting in stable post-peak behavior and mitigation of local buckling. Increasing the spiral plate width up to 40 mm enhanced axial strength by approximately 22%, highlighting its contribution to improved load resistance. Furthermore, the spiral plates were effectively delayed and uniformly distributed local bulging along the column height.
Traditional steel shear walls (SSWs) with flat infill plates have been widely used in regions of high seismic hazard due to their high strength and energy dissipation capacity. However, premature buckling of flat plates reduces their structural performance, motivating the development of trapezoidal corrugated steel shear walls (CSSWs). To further address the limitations of single corrugated walls, double corrugated steel shear walls (DCSSWs) were introduced, followed by hybrid flat-corrugated steel shear walls (FCSSWs), which combine a flat plate with a trapezoidal corrugated plate. This study numerically investigates the lateral behavior of three SSW systems: single CSSWs, DCSSWs, and hybrid FCSSWs. Finite element models are developed using ABAQUS and analyzed under lateral loading. The effects of geometric parameters are examined by considering aspect ratios (L/h) ranging from 0.67 to 2 and corrugation angles of 30 degrees, 45 degrees, and 60 degrees. The results indicate that dual-layer systems (DCSSW and FCSSW) significantly improve structural stability compared with single-layer CSSWs. Among the examined systems, the FCSSW exhibits the most stable nonlinear response, showing no strength degradation up to a 2% story drift. In contrast, the CSSW and the DCSSW with a 30 degrees corrugation angle experience noticeable strength degradation. In terms of peak strength, the FCSSW consistently outperforms the CSSW, with the maximum increase (approximately 15.1%) observed at lower aspect ratios. The DCSSW achieves the highest ultimate strength, exceeding that of the FCSSW by 1.6-4.3% and the CSSW by 3.4-12.3%. Initial lateral stiffness is comparable among all systems, with only minor differences observed.
To improve the stability of coal mine roadway support structures, Huainan Coal Mine was studied as the experimental object, and a Genetic Algorithm (GA) is proposed to optimize the Backpropagation (BP) neural network model. The global optimization and local prediction are coordinated through adaptive coding and other methods. GA is employed to optimize BP weights and thresholds to construct a loosening circle prediction model, and FLAC3D and orthogonal experiments are utilized to optimize support parameters. The experiment shows that the proposed GA-BP model has high accuracy in predicting loose circles. In the optimization of support parameters, the optimal combinations of support parameters for the development roadway, preparation roadway, and mining passage were determined, and the roof settlement under each working condition was controlled within the ideal range, resulting in significant support effects. The stability optimization design method for coal mine roadway support structure proposed in the study can accurately predict the extent of surrounding rock loosening zone and optimize support parameters, providing new ideas and methods for the stability design of deep roadway.
The stability of roadway support structures has a significant impact on the economic benefits and personnel production safety of mines. To analyze the stability state of the mining roadway support structure, this study integrates the support anchor rod and rock structure into a stacked support structure for mechanical characteristic analysis. The optimized Back Propagation (BP) network model in the Stochastic Gradient Descent (SGD) algorithm is introduced to predict the range of loosening circle of mine roadway support structure. The input features of the model include rock rebound value, burial depth, degree of joint development, and tunnel span. In the experiment, the absolute value of the prediction error of the research model is in the range of 1.92 cm to 6.10 cm, with the highest error proportion of 4.9%, and the prediction error is lower than that of other models. Based on the prediction results of the loosening circle range, this study optimizes the parameters of the roadway support structure. Before optimization, the maximum settlement of the top rock layer of the Non-Mining Roadway (NMR) and mining roadway is 43.93 mm and 59.81 mm. After optimization, the settlement and maximum settlement of the top rock layer of the NMR and mining roadway decrease to 32.74 mm and 37.66 mm. The experiment shows that the research method can accurately predict the stability of the mine support structure and has a guiding role in optimizing the mine support structure
Due to its advantages over other earthquake-resistant systems, the use of a concentrically braced frame (CBF) has attracted the interest of researchers in recent years. As compared to other systems, it has several advantages, including abundance, high ductility, good hysteretic behavior and energy absorption capacity, high stiffness, and economic advantages. Buckling-Restrained Braced Frame (BRBF) is one of the new types of concentric braced frames that have been developed in recent years. These frames have high lateral stiffness and an outstanding ability to simultaneously hold earthquakes in energy dissipation features because of the prevention buckling brace. In this paper, the effect of different cross sections of BRBF such as circular, rectangular, diamond, elliptic, and octagon on ductility, resistance, and flexibility coefficient have been investigated by finite element method with ABAQUS software. The results show that the application of BRBF with oval and diamond cross sections for concentric braced frames against lateral loads can be used.
