Analysis To Buffeting Fatigue Of Long-Span Bridge

This dissertation reviews the state-of-art and the potential issues of buffeting and buffeting-related fatigue of long-span bridge. Quick and accurate calculation of the fatigue life caused by buffeting in frequency domain will be an important direction in elaborate analysis of bridges in future. It is the scope of this dissertation to study buffeting of the long-span bridge and buffeting-related fatigue. The main contents are:1. The buffeting analytical theory is explored in time and frequency domains by reviewing the study history and the state-of-art of bridge buffeting.2. On the basis of current non-linear analytic theory for long-span bridge, Moving Reference Point Method is brought forward, which working together with Co-rotational(CR) Formulation, could well tackle with geometrically non-linear analysis for 3-D beam element.3. Research approach in frequency domain for wind-induced fatigue of long-span bridge, based on Markov Process, has been developed. Followed discussion in details on its theory and realization, the approach demonstrates its overriding performance compared with other algorithm on fatigue analysis in sample solution.4. Issues on current bridge engineering softwares are addressed and advantages of OOP(Object-oriented Programming) are discussed. And then enhanced with OOP, BSANSYS(Bridge Structure Analysis System) and ObjectARX-based BSCAD have been developed to well facilitate analysis on wind-bridge coupled vibration and random fatigue.5. The buffeting of Huangpu Nancha Bridge is computed in time domain by using code BSANSYS. The possible influence on buffeting response is investigated by considering geometrically nonlinearity, aerodynamic admittance, motion-excited and buffeting loading. By comparing to buffeting analysis in frequency domain, the validity of the present results is proven. The evaluation of the fatigue endurance of the Nan Cha Bridge is given by rainflow cycle method in frequency domain.