Study On Several Problems Of Design And Analysis For Isolated Buildings

Earthquake is a common nature disaster which can cause heavy casualties, therefore many countries are devoted to engineering anti-earthquake and hazard reduction work. Seismic isolation technology is widely used because of its considerable seismic resistance effect, economy, durability and applicability. But there are some problems to solve in the course of seismic isolation design.In this dissertation, ETABS is used to establish structural model. Main research contents are as follows:1. Vibration characteristics, force and deformation characteristics and damping effects are contrasted to discuss the impacts of modeling methods on results;2. Studying the impacts of parameters of isolation bearings, seismic intensity and natural vibration periods on earthquake mitigation effect;3. Treating the structure as equivalent SDOF, deducing the formula of height width ratio on condition that no tensile force occurs on the bordered bearings and the pressures are not over than bearing capacities, and establishing model to prove the validity;4. Nonlinear static analysis for isolated and non-isolated structure is carried out. Contrasting the results two different analysis methods.The analysis illustrated that:1. For non-isolated structure, seismic response of super-structure will increase as the earth pressure decreases. For isolated structure, seismic response of super-structure is unrelated to the earth pressures, seismic decrease coefficient will decrease as the pressure decreases;2. Period is only related to structure itself and equivalent stiffness of bearings. Seismic intensity and the equivalent stiffness of bearings are two most influential factors of damping effect. There's a linear negative correlation between seismic decrease coefficient and the displacement of isolation layer;3. Limit ratio of height to width will increase as the increasing of structure period when the structure period is less than critical period. There's a reverse rule when the structure period is greater than critical period. The limit ratio gets maximal value when the structure period is equal to critical period;4. Seismic isolation technology defers and reduces the expansion of plastic hinges in the super-structure. The results of time history analysis are higher than the results of nonlinear static analysis. Inverted triangle load action is closer to time history analysis than uniform load on the results.