Fluid-Structure-Soil Coupling Dynamic Response About High Concrete Water Tower And Its Vibration Reduction Method

The high concrete water tower is a kind of special structure in lifeline engineering and it has great strategic significance.The high concrete water tower is also a complex fluid-structure-soil interaction(FSSI)system.The sloshing fluid in the water tank and the interaction between the foundation and soil will affect the dynamic response of the structure.Therefore,the research on seismic and wind-induced dynamic response of the high concrete water tower when considering the fluid-structure-soil interaction will have great reference value for the design of water tower.In this paper,the high concrete water tower is chosen as the research object,with the aid of the finite element software,the finite element calculation model of the water tower-foundation is established.Then,the natural vibration characteristics and dynamic response of the high concrete water tower under earthquake and wind field when considering the fluid-structure-soil interaction as well as its vibration reduction measures are mainly studied,specifically as follows:(1)Firstly,the fluid-solid coupling dynamic analysis theory and fluid-stucture-soil coupling dynamic analysis theory of high concrete water tower are studied.Then the high concrete water tower model and the high concrete water tower-foundation model are established,and the modal analysis is carried out.By comparing the first 10 order frequencies,it can be found that the first 10 order frequencies of the high concrete water tower without considering the foundation effect are higher than the first 10 order frequency of the high concrete water tower-foundation model.Namely,when the foundation soil is considered,the period of the whole water tower-foundation system will be prolonged.(2)In order to study the dynamic response of high concrete water tower under the near-field earthquake with pulse,near-field earthquake without pulse and far-field earthquake with long period when considering the fluid-structure-soil interaction,the finite element calculation models of the water tower-foundation system with different water storage rate are established and calculated.The results show that the high concrete water tower shows different response characteristics under the near-field earthquake with pulse,near-field earthquake without pulse and far-field earthquake with long period when considering fluid-structure-soil interaction.The seismic response of high concrete water tower under near-field earthquake with pulse is the most intense;the seismic response of high concrete water tower under far-field earthquake with long period takes the second place;the seismic response of high concrete water tower under near-field without pulse earthquake is the smallest.(3)By using linear filtering method and programming software MATLAB,the simulation of random wind field is completed.Then,by using finite element software,the water tower-foundation model considering fluid-structure-soil-interation(FSSI),the water tower model only considering fluid-structure interation(FSI)and the water tower model without considering fluid-structure-soil-interation are established respectively.The wind induced responses of finite element models of three different assumptions under random wind field are studied.By comparing the wind induced response of the three models,the effect of soil and fluid on the wind induced response of high concrete water tower is studied.The results show that: the wind vibration response of water tower when considering fluid-structure-soil-interation is different from that of other two assumptions.The displacement response of the model considering FSSI is the most intense,the displacement response of the model without considering FSSI is the second and the displacement response of the model only considering FSI is the smallest.The velocity,acceleration,and stress responses of the model without considering FSSI are the most intense,the responses of the model considering FSSI take the second palce and the responses of the model only considering FSI are the smallest.(4)The dynamic responses of the high concrete water tower under the combined action of seismic wave and wind field are studied.Then the dynamic responses of the high concrete water towers with two types of annular TLD are studied and the vibration reduction effect is compared.The results indicate that:the dynamic responses of high concrete water tower under the joint action of wind field and earthquake are larger than the responses under single factor such as earthquake or wind.That is,the wind field-earthquake joint action will amplify the dynamic responses of the high concrete water tower and cause more serious damage.The vibration reduction effects of two kinds of annular TLD for high concrete water tower remarkable.It is better to choose saturated brine as tuning fluid of TLD than to choose pure water.