研究期間：10108~10207;Numerical Simulation of the Nonlinear Behaviors of Bridge System under Combined Scouring and Seismic Excitations(III) ABSTRACT The safety of bridge under the combined seismic and scouring actions is increasingly concerned topic for engineers in Taiwan. Information of the states and severities of damages under these complicated excitations is very useful to engineers for their design and retrofitting works. The main goal of this project is to develop a computational code that can analyze 3-D multiphase fluid-structural interaction problems. Nonlinear dynamic failure behaviors of bridge structures with various combinations of hydrological conditions, seismic excitations and geographical features of river bed are studied. The capability and accuracy of the developed code will be verified by the research results of other sub-projects under the main project. The work items of each year are listed as following: In the first year of this project, a code named as Solid Truchas will be developed to study the fluid-solid interaction problems containing flexible discrete bodies. In the second year of this project, a shaking table function will be established into the Solid Truchas to simulate those experiments of bridge model with its piers standing in sand shear boxes under earthquake excitations. The validated code will be used to investigate the fluid-structural interaction problems with various hydrological and geographical features. In the third year of this project, large scale problems of bridge with more spans will be studied. Behaviors like the local scouring depth of bridge foundation, erosion and deposition of river bed and vibration and failure of structures by various attack angle of flow will be investigated to gain some information for the purposes of design and retrofitting works of bridge and hydraulic engineering.