Typhoon Kajiki (No. 2513) struck Sanya City, Hainan Province, with wind intensity reaching Beaufort scale 14, making it the strongest typhoon recorded in the region. Through field investigations within the typhoon’s 12-level wind circle and an analysis of meteorological data to determine wind speed return periods, a systematic analysis was conducted on the wind-induced damage patterns and mechanisms of three typical structural types: rooftop photovoltaic (PV) arrays, high-rise building envelopes, and agricultural greenhouses. The results show that the wind speed return period in the affected area was slightly below the 50-year benchmark. Consequently, the resulting wind pressure did not exceed the design specifications for general building structures, and thus did not result in significant failure of primary structural systems. However, the investigation also found that some secondary structural elements sustained damage. The specific causes are as follows: damage to rooftop PV structures was chiefly caused by the failure of connection bolts. For high-rise building envelopes, damage primarily resulted from localized excessive negative pressure, fatigue due to fluctuating wind loads, environmental degradation of material durability, and inherent deficiencies in material performance. Damage to agricultural greenhouse structures was mainly due to the aging of covering films, which reduced their tear and wind uplift resistance, alongside insufficient overall structural stability and stiffness. Based on these damage mechanisms, wind resistance and disaster mitigation measures are proposed, addressing five key aspects: design, materials, detailing, construction, and operation maintenance. This study is expected to provide a scientific basis for disaster management decisions by meteorological, construction, and emergency management agencies, as well as for the typhoon-resistant design of engineering structures.

Most of the existing ancient buildings are in service with injuries, and the internal damage state is complex and diverse. Meanwhile, the reinforcement and maintenance of the ancient buildings carried out by the later generations and the original damage have the opposite impact on the safety performance of the original structure. In order to realize the preventive protection of ancient buildings, it is necessary to quantify the impact of damaged state and repair measures of pure wooden structures on the safety state of ancient buildings. Based on the statistical data of the damaged state of various components of Feiyun Wood Pavilion in Wanrong, Shanxi Province, and combined with existing norms and engineering experience, this paper divides the damaged state of components in detail, establishes a four-level fuzzy hierarchical analysis model, and determines the weight value and judgment matrix of the load-bearing components and the damage types of components in the structure. The security state of Feiyun Wood Pavilion is evaluated by fuzzy analytical hierarchical approach. The results show that the fuzzy analytical hierarchy safety evaluation model established can reflect the damage state and the impact of repair measures on the safety state of Feiyun Wood Pavilion, effectively link structural evaluation with the component evaluation, and verify that the repair measures can effectively enhance the safety and stability of the ancient building structure. The model and method can be applied to the safety grade evaluation of multistorey ancient wooden structures.

Typhoon occuring in the southeast coast of China seriously threatens the structure safety of offshore wind turbines (OWTs). The strong wind and high wave induced by typhoon may damage the control and electric power network system of OWTs, which will lead to the failure of yaw control systems. The load of OWTs increases sharply due to the inability to align with the real-time wind direction, which may lead to some damage or even collapse accidents. In order to study the response characteristics of OWTs in the case of yaw control system failure, taking the 5 MW OC4-jacket supported OWT as an example, numerical calculations were performed to investigate the dynamic responses of the OWT at various yaw angles under different parking positions. Variation of the response of the blades, tower and substructure with the yaw angle was obtained, and the effect of the parking position on the response was analyzed. The results show that, in the case of yaw control system failure, the response of OWTs is very sensitive to the yaw angle and the parking position, and the blade can even suffer an aeroelastic instability at certain yaw angles. Based on the results in the whole yaw angle range, when the turbine is in an idling state or in a standstill state with a 90° parking position, the response of OWTs is relatively weak, thus it is most advantageous to deal with the yaw control system failure condition.