Research Of Hydrodynamic Pressures On Pier In Deep Water

As the development of economy, the construction of bridge is intending to the larger span,deeper water and to be built in offshore areas. Many technical problem were raised in the bridgedesign. At the same time, with the development of large-span, deep-water bridge, the designtheory of deep-water pier is become more and more important. In the new century, China willcomplete the national railway project and a series important highway project, which will includemany bridges across the Changjiang River, Yellow River and some channels to the mainland,such as the Donghai Bridge which is in constructing. The bridge designers of China face thetechnical difficulties of great span and ultra-deepwater foundation, especial the challenges ofseismic theory of deep water pier’s design.Using the method of fluid-solid coupling, the comparing to the respect of seismic responsein the case of air and still in water by ANSYS model is researched. The structure is consideredby the effect of the added mass of the fluid to piers. In this way, the analysis of thehydrodynamic pressure effect to piers is used to solve the problems. According to the Japanesecode of seismic design, the ANSYS model is built. Furthermore, the result of ANSYS model’scalculation was compared with the result of other Japanese experience formula forhydrodynamic pressure.Though the method on pier’s seismic analysis of hydrodynamic pressure, the conclusion isas following: the natural vibration period will enlarge when the pier is in the air than in thewater, the distribution of hydrodynamic pressure presents canopy along the depth of pier.Basing on the revised Morison formula, Trefftz-complete functions were used to form thepotential of the fluid around the pier, and through solving the integral equation based on theboundary conditions. The expression of hydrodynamic pressure is got, as well as coefficient ofadded mass. The different calculation’s methods of additional pressure affect the results ofhydrodynamic pressure. The effect of water level on the dynamic characteristic and seismicresponse of the interaction system is studied.