Wind-induced Dynamic Response Calculation And Parameter Analysis Of Long-Span Flat Roof Structures

Long-span roof-generally light, flexible, low damping and low natural frequencies-is prone to wind and wind load is one of the most important loads to control structure design. When wind flows around roof, the airflow is separated and a high suction zone forms, the flexible roof will suffer from wind-induced dynamic response. But in current Chinese code of wind loads on buildings and structures, there are only some qualitative clauses, but not formula to calculate the wind-induced dynamic response of long-span roof.In the dissertation, the wind-induced destruction mechanism of long-span roof is analyzed; some research methods of wind load and wind-induced dynamic response of long-span roof are compared, and the theory of frequency domain method, which is suitable for computing the wind-induced dynamic response of long-span roof, is deduced in detail; some parameters, which influence the wind-induced dynamic response of long-span roof, are analyzed and then selected, such as mean wind pressure coefficient, angle of attack, power spectrum density, spatial coherence function, damping ratio, terrain roughness coefficient, and so on.The analysis of mode shapes is processed by software Ansys8.0, and the calculation of wind-induced dynamic response is carried out by running some Matlab programs, which are compiled based on the data from the analysis of mode shapes and wind tunnel test. The influences of some parameters on wind-induced dynamic response of long-span flat roof are discussed, including high order mode shapes, vibration modality coupling effects, vertical fluctuating wind, power spectrum density, spatial coherence function, terrain roughness coefficient, angle of attack, damping ratio, and then the influences of angle of attack, damping ratio, power spectrum density and spatial coherence function on gust response factor are discussed. The related contents and conclusions in this dissertation can be referred in engineering design and research in wind-induced dynamic response of long-span roof.