Research On Computing Method Of Wave-Current Force On Sea-crossing Bridge Substructures

The wave-current force can be divided into the connatural wave-current force and the seismic wave-current force on sea-crossing bridge substructures.Based on the mathematical and numerical methods,a lot of studies have been conducted on the connatural effect of the wave-current which includes the effect of currents,waves,and wave-current interaction.The seismic wave-current force is combined with the current force generated by the vibration of the structure in the hydrostatic water and the wave-current force induced by the strong wave-current caused by the earthquake,which is studied through the numerical models and laboratory experiments.The main contents are as follows:1.To research on the CD value curves and changes of the flow field of circular piers and rectangular piers under high Reynolds number is carried out.Based on the inverse method,the CD values of the round-end piers with the different aspect ratio are obtained where the impact of water injection angle is taken into consideration,and comparative analysis of the force for the each pile is conducted in the structure of the pile group.The dynamic response of the composite structure is analyzed by the model of the fluid-structure interaction.2.The influence of wave height,wave length and cross-section on wave force is researched by theoretical and numerical models.The round-end piers are classified according to the scale relation and the methodology for each category is proposed.And the discrepancy between theoretical and numerical models is compared for the wave force on the pile group cap structure.Through analyzing the Mac Camy diffraction theory and suggesting the modification of this theory,the variation law of CM is researched for the scale of circular piers and rectangular piers by numerical models.3.Wave-current force is equal to the wave force plus the current force only in a certain range of application.Based on the relative strength of wave and current,research on the wave-current interaction is proceeded by theoretical deduction and numerical models.The wave-current characteristics are analyzed,and wave-current parameters are compared before and after wave-current coupling,the demarcation point of the weak wave-current and the strong wave-current is defined,then the computing method of each kind of wave-current forces is obtained.4.An integrated method is proposed for improving the shortcomings of the existing methods,which can take into account the additional hydrodynamic pressure caused by seismic rigid body motion and elastic vibrations.Then,comparing the influence of each kind of additional hydrodynamic pressures on the dynamic characteristics of the piers.5.Based on the dynamic similarity conditions of solid and liquid,the simulation concrete is developed,and pier-water coupled shaking table test is carried out.Research on the dynamic characteristics of structure with water depth is carried out by laboratory experiments.And the comparative analysis is conducted between experiments and numerical models for the different results,such as the acceleration response,displacement response,hydrodynamic pressure,and stress response of the structure.6.Wave-current can be divided into mean wave-current,typhoon wave-current and seismic wave-current according to the intensity,Selecting the non-fairway bridge of Hong Kong-Zhuhai-Macao as the computing model,the dynamic response of the bridge under earthquake and the different intensity wave-current are researched,and the strength of seismic effect and wave-current effect are compared.