Study On The Tsunami Force Of Bridge Pier And Optimization Design

Tsunami is a relatively rare natural phenomenon which has a relatively low frequency of occurrence,but it is extremely destructive and has a wide range of influence.Once it occurs,it will induce serious damages to coastal infrastructures where the tsunami occurred,such as residential houses,bridges and breakwaters etc.Two catastrophic tsunamis have happened since the 21 st century,i.e.the 2004 Indian Ocean Tsunami and the 2011 Japan Tohoku Tsunami.Both tsunami caused huge loss of human life and property.Although there is no destructive tsunami in China in recent years,from the perspective of history and domestic scholars have analyzed the risk of a tsunami in China,and there is a risk of a tsunami along the coast of China.In these coastal areas,there are many very significant bridges.According to the survey results of foreign scholars on the place where the tsunami occurred,many bridge piers were destroyed during the tsunami.Therefore,it is necessary to conduct a more in-depth study on the tsunami force of the bridge pier.Although many foreign scholars have done a lot of research on the tsunami force and characteristics of bridge piers with different cross-sectional shapes,few studies have been made on their generation mechanism and cross-sectional form optimization.And in these studies,most of them are carried out for a single bridge pier,and it is very rare for research of the interaction between two bridge piers.In view of the above shortcomings,this paper studies the characteristics of tsunami force and its generation mechanism of a single pier by numerical simulation,and optimizes the cross-sectional form of the pier.The effect of the relative angle between the two piers on the tsunami force was also studied.The main contents are as follows:(1)Foreign “benchmarking” experiments are used to verify the correctness of the grid size,turbulence model and other parameter settings of the numerical model,the numerical calculation method for calculating the tsunami force of the piers is determined,and the grid division method optimized.(2)Based on the flow field and the pressure distribution on the surface of piers,the tsunami force characteristics and its generation mechanism of square,diamond,and circular piers with the same width of the upstream surface and cross-sectional area are studied,and the cross-sectional form of the pier is optimized.And the mechanism of the reduced tsunami force of the optimized pier is also studied.(3)The effect of the relative angle between two bridge piers with a new cross-sectional form on their tsunami force is studied.(4)According to the characteristics of the tsunami wave moving on the optimized pier surface,it is further optimized,and the mechanism of reducing tsunami force is explained.(5)The effect of the relative angle between the two piers with the form of re-optimized cross-section on their tsunami force is compared and analyzed.