Application Study Of Story Isolation In The Intake Tower Frame

Compared with the lower tower structure,the upper frame structure of the intake tower has a smaller mass and stiffness.Under the action of the earthquake,whiplash effect will be generated,and it is easy to suffer serious damage,resulting in the failure of the intake tower to operate normally.In order to ensure the safety and stability of the intake tower in the earthquake,the feasibility of the application of the story isolation technology in the water intake tower is preliminarily studied in this paper.Based on an engineering intake tower,the model of the intake tower without story isolation and the model of the intake tower with story isolation are established by three-dimensional finite element software,and the natural frequency,natural period and mode of the natural vibration are compared and analyzed.Artificial seismic wave fitting,time history analysis of two kinds of intake tower structure,comparative analysis of displacement,internal force(stress)changes of two kinds of intake tower structure;To verify the safety stability of the structure of the intake tower with story isolation against overturning;The sensitivity analysis is carried out by changing the equivalent horizontal stiffness and yield force of the isolation bearing successively by using the method of single factor variable,and the displacement and internal force(stress)changes of the intake tower structure with story isolation are compared and analyzed.The main results and conclusions are as follows:(1)The isolation layer effectively prolongs the basic period of the intake tower with story isolation,makes it avoid the range of the main seismic response frequency band,reduces the seismic damage to the structure,and has a good effect of isolation and shock absorption.The natural vibration directions of the two kinds of intake tower structures are mainly along the river direction and transverse river direction,and the difference is that the vibration deformation of the structure of the intake tower with story isolation mainly occurs in the isolation layer,and the upper frame structure is basically flat dynamic state.(2)The isolation layer effectively reduces the seismic response of the upper frame structure of the intake tower,and its displacement and various internal force values are significantly reduced.(3)Whiplash effect exists in both intake tower structures,but the story isolation technology can effectively alleviate the whiplash effect in the upper frame structure of the intake tower.(4)After the isolation layer is added on the top of the intake tower,the vertical normal stress on the bottom surface of the tower body does not show tensile stress,and the horizontal displacement and stress of the isolation bearing support meet the requirements of the code,so the structure of the intake tower will not capsize.(5)Parameters such as the equivalent horizontal stiffness and yield force of the isolation bearing have similar influence rules on the displacement and internal force(stress)of the structure of the intake tower with story isolation,but the sensitivity is different,and there is an optimal value for each parameter.Above all,isolation layer can effectively extend the fundamental period of intake tower structure,dissipation of seismic energy,reduce the earthquake response of the upper frame structure of the intake tower,has good vibration isolation effect of shock absorption and story isolation technology in the application of the intake tower frame has the feasibility,reasonable selection of various parameters of the isolation bearings,can make the isolation layer better play its isolation shock absorption effect.