For the risk of gas leakage and explosion that may occur during the serviceability of urban natural gas pipeline, based on the numerical simulation conducted by FLACS, the gas leakage, explosion and disaster risk under the different speed of wind are mainly studied with local climate characteristics for actual urban street. The results show that the wind speed has an obvious effect on the gas leakage and diffusion, the deviation of gas leakage direction is not obvious for the smaller speed of wind at the initial stage, the horizontal diffusion range gradually increases with the increase of wind speed, while the vertical diffusion range gradually decreases, and the volume of gas at the limit concentration of combustion and explosion gradually decreases. In urban buildings, the overpressure load of higher buildings is lower. After the explosion, the peak overpressure at the same monitoring point decreases with the increase of wind speed. With the increase of distance from the building to the explosion location, the overpressure load on the building decreases and the oscillation effect of overpressure load is relatively gentle. The thermal radiation after burning has great influence on the surrounding buildings and downwind position, especially the buildings around the leakage point.

Origami structures contributed to the design of composite materials with excellent mechanical properties. In our previous work, the GO sheet was folded through the coordination and electrostatic interaction among oxygen atoms and Cu²⁺. The folded graphene aerogel (fGA) was constructed with folded graphene oxide sheets (fGO). However, the effect of pore structure parameters on the mechanical properties of fGA was neglected. Therefore, based on fractal theory, the pore structure of fGA was parametrically quantified using the fractal dimension (D_f) in this paper. The elastic behavior of fGA was investigated through the mean-field homogenization fractal model (MHFM). The results showed that the fGA elasticity property exhibited a non-linear decreasing trend as the D_f increased. The fGA with abundant pore structures was constructed by fGO, and these pores were essential for the structural stabilization of the aerogels. The excellent mechanical properties were possessed in fGA. As the pore size distribution of fGA became uniform, the variation of its elastic properties tended to stabilize.

Owing to their lightness, high strength, flexibility, and design adaptability, cables have been extensively employed in architectural engineering. As cables are primary load-bearing components in long-span spatial structures, a profound understanding of their mechanical behavior is essential for structural design and safety evaluation. This paper presents a systematic review of the physical and mechanical properties of cables commonly used in building structures, offering reference data for key performance indicators. The mechanical responses and influencing factors pertaining to major types of cables—such as semi-parallel wire strand (SPWS), Galfan-coated steel strand (GSS), and full-locked coil wire rope (LCR)—are thoroughly examined. This review covers five critical aspects: fundamental cable characteristics, stress relaxation and creep, mechanical performance under high temperatures, corrosion-induced degradation, and post-fracture behavior after fatigue-induced wire breaks. It identifies key mechanical parameters, including elastic modulus, axial stiffness, bending stiffness, and the coefficient of thermal expansion. The degradation behavior of cables under high-temperature and corrosive conditions is examined, highlighting the superior corrosion resistance of LCR and GSS. Furthermore, the redistribution of stress and residual capacity after the rupturing of steel wires is elucidated. Based on recent studies, prospective directions are suggested to address current knowledge gaps and advance design strategies focused on durability and performance for forthcoming cable-supported structures.

Previous studies of train-induced tunnel responses have mainly focused on completed tunnels or symmetric loading conditions, while the dynamic behavior of unfinished double-arch tunnels subjected to unilateral train loading through temporary trestles remains insufficiently understood. To address this gap, this study investigates the asymmetric load-transfer mechanism and short-term structural response of an unfinished double-arch tunnel–trestle system and identifies critical locations for construction-stage monitoring and speed control. A three-dimensional ABAQUS model was established for train speeds of 10–70 km/h and validated using a 63-day field-monitoring program comprising 15 train passages at speeds of approximately 9.4–56.2 km/h. Both numerical and monitoring results show that stress and deformation increase with train speed and are concentrated at the loaded-side invert, lower middle partition wall, and trestle wheel-load region. At 70 km/h, the calculated maximum lining compressive stress and trestle stress reached 6.353 and approximately 172 MPa, respectively, while the maximum horizontal deformations of the loaded and unloaded tunnel bores were 1.110 and 0.565 mm. At the maximum monitored speed of 56.2 km/h, the measured peak compressive stress of the middle partition wall was 5.95 MPa. The mean monitoring-to-simulation ratios for the evaluated responses were approximately 0.94–0.97, demonstrating satisfactory agreement and a slightly conservative numerical prediction. The results clarify the asymmetric coupling response of the tunnel–trestle system and support the identification of sensitive monitoring locations. Based on the combined numerical and field evidence, approximately 30 km/h is recommended as a conservative, project-specific construction-stage operational-control value. This study provides a quantitative basis for monitoring and risk control in similar temporary rail-transport projects, although further verification under different geological, structural, and loading conditions is required.

Structural engineering is currently at a critical stage of development, driven by growing global demands for sustainability, resilience, and construction efficiency