Buffeting Analysis For Long-Span Cable-Stayed Bridge Tower In Mountain Area

The height of cable-stayed bridges towers are becoming higher as a result of increased bridge span. Normally seen as tall and slender constructions, the free standing towers suffer wind loading, an important external loading. The study pertaining to the wind loading effects on towers has drawn much attention and constitutes large part of large span bridge wind resistance research due to the increased tower height.In the paper, some theories concerning natural wind and buffeting are firstly introduced. Based on the theories, a practical application of Beipanjiang Bridge tower buffeting time domain analysis is conducted by a MATLAB program simulating two dimensional pulsation wind field and a construction analyzing model established by finite element software ANSYS. A comparison is made between the theoretical analysis results and testing results, obtained by wind tunnel tests. The details are as followings.1. Currently study of bridge buffeting issues and some fundamental knowledge of tall and slender construction are introduced.2. Basic wind characteristics and wind induced issues of tall and slender construction are described.3. The simulation of tower two dimensional pulsation wind field is established by the simulating MATLAB programs based on harmonic number superposition principle, the bridge configuration properties, and the consideration of the different wind speed in different tower heights.4. The establishment of tower model, natural vibration characteristics analysis, and the buffeting response time domain calculation are achieved with the help of simulation wind field and ANSYS.5. Acceleration responses at the top of the tower in each angle are obtained by wind tunnel tests. And thusly the RMS of buffeting displacement could be calculated.6. A summary and some useful conclusions are made.