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大跨度屋盖结构属于风敏感结构,风与结构的相互作用十分复杂,风荷载常常是设计的主要控制荷载之一。以某电厂大跨度屋盖为研究背景,获得了结构的自振动力特性。基于风压谱拟合和风压时程本征正交分解(proper orthogonal decomposition,POD)重构原理,提出了一种修正的频域法,该法直接采用风洞试验得到的风压数据建立屋盖整体风压模型,通过快速傅里叶变换(fast fourier transform,FFT)转化为风压谱,在精确拟合屋盖计算点风压功率谱的基础上,获得屋盖结构的风致响应,同时推导了屋盖无量纲风压谱的表达公式。研究了结构位移均方根值和加速度均方根值的分布特点,同时得出了屋盖的风振系数分布特点。研究结果表明修正频域法抛弃了准定常假设,计算结果具有较高精度,可以作为大跨度屋盖结构抗风设计的参考。
Long-span roof structures are wind-sensitive structures and the interaction between wind and structure is very complicated. Wind loads are often one of the major control loads of the design. Taking the long-span roof of a power plant as the research background, the self-vibration dynamic characteristics of the structure are obtained. Based on the wind pressure spectrum fitting and the principle of proper orthogonal decomposition (POD) reconstruction, a modified frequency domain method is proposed, which uses the wind pressure data obtained from the wind tunnel test to establish the whole roof The wind pressure model was transformed into wind pressure spectrum by fast fourier transform (FFT). Wind power response of the roof structure was obtained by accurately fitting the wind pressure spectrum of roof calculation point. At the same time, Expression Formula of Roofless Dimension Wind Pressure Spectrum. The distribution characteristics of rms value and acceleration root mean square value of structure displacement are studied. At the same time, the distribution characteristic of wind vibration coefficient of roof is obtained. The results show that the modified frequency domain method abandons the quasi-constant hypothesis, and the calculation result has high precision and can be used as a reference for wind-resistant design of long-span roof structures.