Buffeting-induced stress analysis of long-span twin-box-beck bridges based on POD pressure modes

Buffeting-induced stress analysis is imperative for the assessment of local failure and fatigue damage of long-span cable-supported bridges located in strong wind regions. This paper presents a new framework for buffeting-induced stress analysis of long-span twin-box-deck bridges based on the pressure modes obtained from the proper orthogonal decomposition (POD) of wind-induced fluctuating pressures and the substructure-based finite element (FE) model of the bridge. Distributed aerodynamic and aeroelastic pressures on the surface of the twin-box deck are modelled in terms of POD pressure modes. The substructure modelling scheme is adopted to construct the FE model of the bridge so that POD pressure modes can be applied and both global (displacement and acceleration) and local (stress) responses of the bridge can be captured simultaneously and accurately. The pseudo-excitation method is used to solve the governing equations for buffeting-induced stress analysis in the frequency domain. The Stonecutters cable-stayed bridge of a twin-box deck under Typhoon Hato is selected to examine the feasibility and accuracy of the proposed framework, in which the global and local responses of the bridge under Typhoon Hato are computed using the proposed framework and compared with the measured ones recorded by the wind and structural health monitoring system installed in the bridge. The comparative results show a good agreement between the computed and measured responses and confirm the necessity of the proposed framework for buffeting-induced stress analysis.