Research Of Bridge Seismic With Wave Force

With the development of economy and the progress of technology, the span of bridge is gradually larger and long-span bridges are springing up all over the country. The water depth of long-span bridges which spans wide waters is often deep. Deep-long-span bridges are in waters where the wind wave is big and the water surface is broad. Wind waves are one of important loads. Earthquakes, especially strong earthquakes, bring a great threat to the safety of deep-long-span bridges. Besides, when earthquakes, the bottom of waters or reservoir bank motion caused by ground motion will cause strong water motion which contains a huge amount of energy. At this time, bridge structure is under the joint action of wave and earthquake while current seismic designs often ignore water effects considering the structural seismic performance without water separately or only consider the coupled vibration of structure and water caused by earthquake ignoring wave force effects. So it is necessary to study bridge structure seismic performance with wave force.In this dissertation, seismic response of bridge structure with wave force is studied. The main contents are background and present situation of the research, water and structure interaction system theory, seismic water pressure calculation methods in common use, three dimensional numerical wave flume simulation, bridge structure seismic response with wave force. Specific research is as follows:This dissertation briefly introduces the relevant provisions and formulas of dynamic water pressure in the highway codes and railway codes and deduces Morrison equation with linearization. Morrison equation is a widely used empirical formula for engineering practice. It is a very common method which is also used in calculation and analysis of dynamic water pressure. Theory of radiated wave is introduced including its fluid control equation, boundary conditions and the process of dynamic water pressure.Basic formulas of linear wave theory and second-order Stokes wave theory are introduced. Wave parameters have different input values by different wave theories to make waves using boundary wave-made method. Principle of boundary wave-made method, wave motion control equation and free surface tracking VOF method are introduced which provide 3D numerical wave simulation a theoretical basis. 3D numerical wave is got by CFD software using boundary wave-made method that according to different wave theories wave parameters which like inlet boundary velocity and wave height etc. are given to establish 3D numerical wave tank.By using 3D numerical wave flume, wave force is applied to a continuous rigid frame bridge based on an actual engineering to investigate seismic response of bridge structure with wave force. The existence of the wave force changes the natural frequency of the structure and the frequency of each order is reduced. This shows that wave force can change dynamic characteristics of structure. The existence of wave forces changes dynamic response of structure and increases dynamic response of structure to different degrees and the change could not be ignored. When seismic response of bridge structure analyses, effects of wave forces should be considered. When effects of wave and earthquake are included, because both alone in dynamic response peak is not at the same time, so also included the impact of both structure dynamic response peak is not is both alone in sum of dynamic response.