Study On Wind Effects On Long-Span Ellipsoidal Surface Roof And Conical Surface Gladding

Along with the development of science and technology,a number of long-span flexible roof structures with beautiful shapes and new structural systems are widely applied into the public constructions,for example,gymnasium,hangar and theater. When wind flows around roofs,the airflow will be separated to form a high suction zone,and the flexible roofs will suffer from wind-induced buffeting response. So far,a limited number of research papers are related to dynamic responses of long-span flexible roofs at home and abroad. So it is important to study on wind load and wind-induced dynamic response for long-span flexible roof structures in the field of engineering and research.Hangzhou Grand Theater's main part is 170m long and 136m wide,and the surface of it is consisted of ellipsoidal surface roof and conical surface gladding. Based on wind tunnel test and theoretical analysis,the vibration mechanism,vibration shape,dynamic response and wind load factor of long-span combined structure consisted of ellipsoidal surface roof and conical surface gladding subjected to wind excitation are analyzed systematically in this dissertation,and some valuable results are obtained.Based on the data of wind pressure gotten from the wind tunnel test on rigid model,the mean wind pressures and fluctuating wind pressures on the long-span combined structure are studied. The distribution of mean wind pressure is analyzed and compared with the distribution on similar structural surface. Through summarizing the rules for wind direction affection on wind pressures distribution,the most dangerous wind directions are gotten. When the rules for fluctuating wind pressure distribution and wind direction affection on it are summarized,the relationship of the fluctuation wind pressures and the mean wind pressures are analyzed. Depending on the power spectrum compare of simulated fluctuating wind pressures based on the quasi-static assumption and measured fluctuating wind pressures,the practicability of quasi-static assumption in fluctuating wind pressures computing on similar structure surfaces are also discussed.The finite element model of Hangzhou Grand Theater's structure is built up. Through the modal analysis on the model,the structure and structural natural vibration characteristics are presented along with the key elements' influence on the natural vibration characteristics. Displacement dynamic responses,acceleration dynamic responses and wind direction influence on them are discussed in the time-domain and the frequency-domain. Finally displacement wind load factor and inner force wind load factor are calculated and compared. The applicability of them is offered for design reference,based on the analysis of the difference between their values.