Study On Dynamic Characteristics Of Long-span Double-layer Reticulated Spherical Shell Of Bunker Under Seismic Motions

After stepping into the twenty-first century, economic prosperity has led tothe development of long-span space structure. In our country, construction ofindustrial and civil buildings face a high-speed development. Many long-spangymnasium and industrial factory buildings can be seen in anywhere. Bunker, as aindustrial building, is widely applied in practice. Because of a series of dangerousearthquake happened all over the world, the study on seismic motions forlong-span shell structure has become a hot topic.The content of the thesis includes following parts mainly:(1) The shell is used to have a modal analysis. Considering single andmultiple direction input of El-Centro earthquake. Through the elastoplasticanalysis, as for multiple direction, the maximum displacement of the structure is15.22cm that is increased about24.7%than single direction. The maximum axialtensile stress is246.50Mpa, which is increased18%. There is81beams that reachinto plastic stage and the maximum plastic strain is7.1e-4. And it is increasednearly91.9%. Besides, TAFT and Tianjin waves are used to prove the results.Also, the long period earthquake waves are analyzed in this article.(2) Establishing the wave passage effect model, the structure is analyzed infour conditions. Through the analysis, it is found that with the decrease of thewave velocity, the displacement, acceleration and axial stress are decreased either.The axial stress of the radical direction beams along the earthquake wave isincreased when the wave velocity get larger, while the value of the beamsperpendicular to the wave direction is smaller. And the axial stress of the hoopbars will be increased while the wave velocity gets smaller.(3) The radical displacement of the silo is calculated in four conditions. Andit is added into the shell bearings as a initial condition. Through the analysis, thecritical value of the radical displacement is79mm. El-Centro earthquake is usedin this research. With the increase of the radical displacement, the value of thepressure stress of the upper chords is increased, while the lower chords isdecreased. In both way, the tensile stress vaule of the hoop bar is increased.