Seismic Response And Stabilization Analysis Of A Double-layer Ellipsoid Reticulated Shell Roof Structure

Reticulated shells are typical models of space structures, which have their intrinsic mechanical properties. Since the beginning of the20th century, with the improvement of material and spiritual civilization, the space frame structures has been a rapid development in many countries due to its’ unique architectural features and superior structural performance. However, because a variety of structural failures emerge uninterrupted, we should pay a great attention to its mechanical properties now.The paper choose the roof structure of a stadium as background, use double-layer ellipsoidal reticulated shell whose designed parameters meet the standard requirement as the research object, and adopt finite element program "SAP2000" to study seismic performance and stability. The main content as follows:1. The thesis firstly described the general situation of project, structural style, calculation model, load cases and load cases combination, then discussed the base reaction,displacement, axial force and member stress of this structure based on linear analysis of its static characteristic by SAP2000.2. The paper did an analysis of its’ natural vibration characteristics and pointed out that the distributed natural frequencies was so densely and complex, with lots of vertical vibration modes. If we use mode superposition response spectrum(MSRS) to do follow-up analysis, oscillation mode coupling must be considered, furthermore, more numbers of modes should be calculated in order to make the results relatively accurate.3. Based on mode superposition response spectrum, the paper studied seismic response of the shell under the separate action of X, Y and Z seismic. Give the conclusion that dynamic internal force of the top chord and bottom chord members showed a regularly change in all cases. Particularly under the action of Z seismic, response of the structure was more serious than that of X and Y. It also showed a different change compared with X and Y.4. based on the stability theory, I analysis structure elastic buckling under three conditions and make the nonlinear analysis considering the influence of initial defects. Structure stable safety coefficient was obtained under geometric nonlinear effect through load force-displacement curve abtained by two different methods, and elastic instability process was studied. The results said that displacement increment method is better than another, and safety coefficient of the linear eigenvalue buckling analysis is obviously big, which just could be a reference. Considering that the influence of initial defects is less smaller, but geometry nonlinear greatly influenced the structure stability. It is concluded that we should consider geometrical nonlinearity influence in the process of double-layer ellipsoidal reticulated shell stability analysis.Through analyzing seismic performance and the whole stability of the double-layer ellipsoidal reticulated shell roof structure, problems on calculation and analysis were introduced in this paper, it can be a reference for similar projects.