This study investigates the tensile behavior of pultruded composite square tubes with single- and double-bolt joints to evaluate their ultimate load-bearing capacity and failure modes. A series of experiments was carried out to examine the effects of hole size, edge distance, and the presence of a reinforcing gasket on joint performance. The results indicate that incorporating a multiaxial fiber-reinforced resin matrix composite gasket significantly enhances joint strength, achieving up to a 295% increase in bearing capacity. In single-bolt configurations, reducing the edge distance improved the effectiveness of the gasket, leading to higher ultimate strength, as it enhances the lateral confinement of the gasket. For double-bolt joints, a shorter spacing between holes further amplified the reinforcing effect of the gasket under constant hole size and edge distance. A theoretical model was developed to estimate the ultimate load, and the calculated results showed strong agreement with experimental observations. Numerical predictions showed a strong correlation with experimental findings, confirming the model’s reliability and accuracy.

Slab–column structures are susceptible to sudden punching shear failure at connections due to the absence of traditional beam support, prompting the need for effective damage monitoring. This study employs an acoustic emission (AE) technique to investigate the failure process of reinforced concrete slab–column specimens, analyzing basic AE parameters (hits, amplitude, energy), improved b-value (Ib-value), and RA–AF correlation, while introducing a Gaussian Mixture Model (GMM) to establish a unified index integrating crack type identification and energy information. Experimental results show that AE parameters can effectively track different stages of crack development, with Ib-value reflecting the transition from micro-crack to macro-crack growth. The correlation between AE energy and structural strain energy enables quantitative damage assessment, while RA–AF analysis and GMM clustering reveal the shift from bending-dominated to shear-dominated failure modes. This study provides a comprehensive framework for real-time damage evaluation and failure mode prediction in slab–column structures, demonstrating that AE-based multi-parameter analysis and data-driven clustering methods can characterize damage evolution and improve the reliability of structural health monitoring.

Ground and building settlements induced by tunneling excavation are common in cities. Such settlements can cause instability of the ground and threaten the safety of the upper infrastructures or build...

Ground and building settlements induced by tunneling excavation are common in cities. Such settlements can cause instability of the ground and threaten the safety of the upper infrastructures or build...

Metro construction in ecologically sensitive areas faces a major construction management challenge, as high energy use and environmental impacts can compromise the construction legitimacy required under strict regulations. Existing studies mainly focus on isolated technical solutions or retrospective evaluations, providing limited guidance on their systematic integration into project-level management. This study develops a five-stage meta-network framework grounded in Resource Dependence Theory (RDT) to assess and enhance energy-saving capability by translating external legitimacy pressures into manageable internal resource relationships. The framework systematically evaluates energy-saving capability by analyzing coordination among agents, tasks, energy types, and knowledge. Using Wuxi Metro Line 5 as a case study, clear stage-specific variations are identified, with task–energy matching reaching its lowest level during earth excavation and the recurrence of task–energy resource relationships reaching its highest level during main structure construction. Results show that energy-saving capability can be strengthened through coordinated resource integration, while energy-structure transformation contributes to managing external dependencies and maintaining construction legitimacy. The framework supports proactive construction management by diagnosing coordination deficiencies and guiding resource optimization, while extending RDT to sustainable metro construction management.