Nonlinear Seismic Response Of Super-Large Natural Draft Cooling Tower

Natural draft cooling tower is an important part of thermal power plant and nuclear power plant, its safety concerns economic development greatly. A number of factors should be taken into account in the design of cooling tower, in which seismic-resistance is an important aspect. At present, most research on dynamics of cooling tower is based on FEM. However, in China, the linear model is usually adopted to design and research the cooling tower for a long time. This is not a small difference with the characteristics of the concrete. Therefore, it’s significant to study the dynamic of natural draft cooling tower using concrete nonlinear constitutive model, also considering the reinforcement.In this paper, a cooling tower 3-D solid model is established to study linear and nonlinear time history analysis, based on general finite element software ABAQUS. The concrete damaged plasticity model is selected for nonlinear analysis, while choosing linear elastic constitutive model for linear analysis. Comparison of linear and nonlinear dynamic response, the stress, acceleration and displacement value is not very different under 8 and 9 degree waves, while there is a big difference under 10 degree waves. Through detailed analysis of nonlinear dynamic response, the columns’ stress is the largest part of the cooling tower structure, and the shell’s stress decreases with increasing altitude. And the shell’s stress is much smaller than the columns’. The acceleration and displacement is more sensitive with the shell’s height increases, and the value is larger. It is showed that the columns is the weak part of the cooling tower, the columns and some part of shell are into nonlinear under big seismic.To study detailed seismic analysis of the columns, which is the weak part of the cooling tower, the seismic performance with different crotch distance and different number of columns is studied. The seismic performance is promoted while the crotch distance is reduced; it is benefit for the seismic performance by increasing the number of columns, without the effects of other factors.