Study On Dynamic Resonses And Antivibration Measures Of The Sea-crossing Bridge Under Wave Loads

With the continuous development of China's economic construction,China's bridge engineering industry has also been developing rapidly,and many sea-crossing bridges have been designed and built successively.For example,Qingdao Jiaozhou Bay Bridge,Hangzhou Bay Bridge,Hong Kong-Zhuhai-Macao sea-crossing bridge,Zhoushan sea-crossing bridge and so on.These different forms and sizes of sea-crossing bridge structures are built in the ocean.The sea surface is broad,the water depth is deep,and the environment of the sea is complex and changeable.Therefore,the calculation of wave forces on cross-sea bridges is very important for bridge design.At the same time,the dynamic response of bridge under wave load and seismic load is worth further studying,as well as the vibration isolation of different bearings.In this paper,the dynamic response of the cross sea bridge under wave action and the seismic isolation effect of different types of bearings are studied.The research contents are as follows:(1)Compare calculation method of domestic and international specifitions about wave force on pile foundation,pier column,vertical dike(large scale platform).The relevant regulations and calculation principles of the wave force on large and small scale piles are introduced in this paper.Then,compared the relevant calculation codes and formulas about wave force on vertical wall structure under regular wave,breaking wave,broken wave action,Specifically,the wave pressure distribution,the calculation formula,the wave force calculation parameters are compared in detail,and the applicable conditions of relevant provisions in various countries' codes are also given.(2)Matlab program has been compiled to calculate the wave forces on the substructure of the cross-sea bridge.The wave forces of single pile,pile group and pile cap of the cross sea bridge are solved by importing the geometric parameters of the actual bridge substructure.Then,by changing the water depth of 28.5m,30 m and 31.5m,the wave force and wave moment of the bridge were analyzed under the three kinds of water depth.The proportion of the wave force of the cap to the wave force of the whole substructure is compared,this paper puts forward some suggestions for the selection of the lower structure of the bridge.(3)The dynamic response of the actual cross-sea bridge is studied by applying seismic load and the wave force load which calculated by matlab.First,the dynamic characteristics of a simple supported beam bridge under water and no water conditions are calculated.It is found that the natural frequencies of the structure are reduced when considering the water load.At the same time,two different types of bearings are set up.It is found that the dynamic response of the bridge pier and the beam is obviously reduced after the lead rubber bearing is installed.The damping effect of lead rubber bearing is obvious.