Shaking Table Test Study And Theoretic Research Of Tall Flexible Tower Structure

Destroys resulting from seismic action are quite complicated processes, which are generally supposed to be caused by ground horizontal, vertical and torsional earthquake. The seismic response phenomena of tall flexible tower structures such as reinforced concrete chimney, airport control tower and tall flexible tower buildings have not been studied clearly and some earthquake phenomena have no appropriate explanation. The vertical earthquake action to tall flexible tower structures is still in disputation, hence it is necessary to study the seismic response of tall flexible tower structures. In this paper, research on seismic response of tall flexible tower structures is performed through shaking table test and finite element analysis. The destructive earthquake and the economical loss since 20th century in our country are summarized. The investigation status of horizontal earthquake and vertical earthquake of tall flexible tower structures is commented in detail.A 1/30 scaled reinforced mortar model of a control tower of Beijing airport is tested on shaking table. The dynamic characteristics and seismic response are recorded and analyzed. The dynamic characteristics and seismic response of the prototype structure are derived by the similitude relationship according to the testing results. The dynamic calculations of the model and prototype structures are also performed using structural finite element analysis program, which are compared and analyzed with the test. Range and frequency spectrum of vertical earthquake are studied basing on recorded vertical earthquake waves. Many earthquake Phenomena that are related to vertical seismic response are introduced. The influencing factors to vertical seismic response of tall flexible tower structures are studied by three-dimensional spatial finite element model in the case of typical structure, which reveals that vertical dynamic properties of tall flexible tower structures are mainly relate to height and mass ratio of horizontal members to entire structure. According to the analysis results, the simplified formula of primary vibration period of tall flexible tower structures is presented. The earthquake actions of tall flexible tower structures are computed by response spectrum method and the dynamic calculations method respectively for typical tall flexible tower structures. The computation results reveal that vertical seismic response are also mainly relate to height and mass ratio of horizontal members to entire structure. According to the results, the simplified formula of vertical displacement and vertical earthquake action of tall flexible tower structures under earthquake is presented. The nonlinear seismic responses of tall flexible tower structures under vertical earthquake action, horizontal earthquake action, vertical and horizontal earthquake action together by finite element program are obtained. The nonlinear performance of reinforced concrete structures under earthquake action is analyzed together with the seismic capability of tall flexible tower structures under vertical and horizontal earthquake action together.