RESEARCH ON SEISMIC PERFORMANCES OF HYBRID STRUCTURE HEAT ABSORPTION TOWERS BY SHAKING TABLE TESTING

As a structure with the first safety grade, heat absorption towers are characterized by high positions of cantroids, large loads and low damping. The equipment itself is prone to produce large additional bending moment and whipping effect under the action of earthquake. Therefore, it is very important to study the seismic performances of the structure. A 242.7 m high hybrid structure of heat absorption tower with the concrete bottom and steel top was taken as the research object. According to the results of simulations by SAP 2000, the simplified design scheme of the scale model was determined. The equivalent scale model was designed and processed according to the scale ratio of 1/20 and the shaking table test was conducted under the actions of three directional earthquakes. The dynamic characteristics of the model, the response of acceleration, displacement and strain of the structure under different intensity earthquakes were tested. The rationality of model design and fabrication was verified by finite element analysis, and the damage of the model as well as the regularity of seismic responses were analyzed. The results showed that under the action of frequent occured earthquakes, fortification and rare occured earthquakes, the maximum displacement angles of the structure were 1/516, 1/281 and 1/145 respectively, it showed the seismic performances of the structure generally met the relevant design requirements. The concrete bottom and variable sections in the middle of the tower were relatively weak, and the whipping effect was obvious in steel structure part, which needed to be paid attention to.