Long span bridges are very important for the development of modern economy, and increasingly become one of the symbols of modern civilization. Long span bridges with high flexibility and low damping exhibit more sensitive under a seismic loading because of their complex dynamic characteristics. Their unique mechanical behaviors challenge the existing knowledge frame. The treatment of stochastic uncertainties of system properties and stochastic seismic process, and computing of probability distribution and reliability in life period of the bridge, becomes more and more important. Not only the non-stationary inhomogeneous random fields of ground motion, but also the uncertainties of models such as geometric and material should be considered. In this background, the project team will establish a practical method based on the latest study in the field of random vibration and computational mechanics and investigate the failure mechanism under multiple excitations by using the large-scale shaking tables. Through theoretical, numerical and experimental interactive supply and confirm propose effective seismic evaluation index to improve the security of structure under earthquake loadings. This study not only has broad application prospects, but also improves the development of the seismic theory.