Passive Interaction Control For Seismic Response Of Parallel Structures

Buildings in a crowded city are often built closely to each other because of the limited availability of land. Some of high-rise building structures are designed to be composed of several substructures because of functional application. It is considerably possible that pounding between adjacent structures may occur. Coupled building control strategy has been shown to be an effective method of protection for adjacent structures. This application takes advantages of the interaction between neighboring structures which is expected not only to prevent the pounding problem of the adjacent structures but also to reduce seismic response of the adjacent structures. Therefore, it has great significance to study on this subject. In this dissertation, the following aspects are studied through theoretical and numerical analysis, some important results and conclusions have been achieved as follows:(1) On the basis of theoretical expressions of Kelvin model defined or Maxwell model defined damper between two single degree of freedom system. Through theoretical derivation, the results showed that the optimum parameters of Kelvin model defined and Maxwell model defined dampers between two multi degree of freedoms structures are closely relate to the first circle natural frequencies and the sum of mass of adjacent structures. A pair of parallel structures with different heights subjected to filtered white noise excitation is taken as an example. The optimal values of Kelvin model defined and Maxwell model defined damper between adjacent structures are sought by means of extensive parametric analysis. Through comparative study, it can be found that the numerical results and theory results are consistent with each other well.(2) Coupled building control strategy is applied to the twin-tower structure with large podium. Through the comparisons of theory results and numerical results for optimum parameters between twin-tower structures with large podium under filtered white noise excitation, the results show that the appropriate parameters of dampers can be computed by the first circle natural frequencies and the sum of mass of twin towers. Then, the coupled building control strategy is compared with the shared tuned mass damper (STMD) method, it can be discovered that the former is better than the latter obviously. Based on a practical twin-tower structure under actual earthquake records, the differences of optimal parameters of dampers between parametric study and theory results are evaluated, the results proved that the applicability of analytical expressions of Kelvin model defined and Maxwell model defined damper between two single degree of freedom systems.(3) Dynamic analysis is carried out to the coupled building control strategy with the consideration of the variability of structural parameters and damper parameters. On the basis of adjacent stochastic structures connected by dampers, the dynamic responses of adjacent structures subjected to actual earthquake records and non-uniformly modulated evolutionary excitation are analyzed. The results show the robustness of coupled building control strategy, and the random responses of adjacent structures are mitigated effectively.(4) An improved genetic algorithm is used to deal with the optimal design of positions of dampers between two adjacent structures. The optimal parameters of Kelvin model defined element or Maxwell model defined element between adjacent high-rise structures is obtained based on the equivalent single degree of freedom system, the first circle natural frequencies and the sum of mass of adjacent structures are taken as parameters. Crossover operator and mutation operator in the binary-coded genetic algorithm are improved, in order to solve the optimal distribution problem of damper while the number of dampers is determined. Then, the dynamic responses of two multi degree of freedom structures are compared with thoes of two equivalent single degree of freedom system, the results show that the optimum parameters of Kelvin model defined element or Maxwell model defined element between adjacent multi degree of freedom structures can be achieved based on the two equivalent single degree of freedom system.(5) The behavior of viscous fluid damper applied in coupling structures subjected to near source earthquake is studied. The structural nonlinearity is characterized by Bouc-Wen model and several near fault ground motions are simulated by the combination of a recorded earthquake (background ground motion) with equivalent velocity pulses that posses near fault features. Extensive parametric studies are carried out to find the appropriate damping coefficient. Performances of viscous fluid dampers are demonstrated by the relation between the force and displacement, the maximal damper force and stroke. The control performances are demonstrated in terms of the response reductions of adjacent structures. Results show that the dynamic responses of adjacent structures are mitigated greatly. Proper damping coefficients of connecting fluid dampers have a little difference, while adjacent structures under different near fault ground motions with the same peak acceleration. Satisfied viscous fluid dampers can be produced according to the current manufacturing skills.