Study On Seismic Response Of Primary-Secondary System Based On Coupled Effect

In recent years, more and more civil engineering structures tend to be large-scale and complicated along with technological progress and economic development, which lead to plenty of coupled system composed by a number of sub-structures, such as a lot of decorative and functional building non-structural components attached to the main structure of the building, important mechanical and electrical equipments comprehensively adopted in the production and life, damper devices installed in buildings in order to resist complex environment loads, et al. As be shown above, such complicated system can be grouped into primary-secondary system which is composed by multiple subsystems with different dynamic characteristics and exicsts the relationship between primary and secondary. The structure is referred to as primary system, and the mechanical and electrical equipments, structural appendages and damper devices are collectively referred to as secondary system. Because the secondary systems damaged in the earthquake would cause huge economic losses, a lot of researchers have been devoted to the seismic response of such systems since 80s of the last century, and some meaningful research work are in progress. Especially in recent years, with the development of performance-based seismic design, aseicmis design and seismic control of secondary systems attract more and more researchers' attention. Primary-secondary systems have significantly different dynamic characteristics distinguished with the ordinary building structures, the traditional real modal decomposition method as well as the response spectrum theory, because of failing to properly account for the distinctive characteristic, would introduce unnecessary errors or mistakes and are no longer applicable in theory. Therefore, it is necessary to carry out specialized research and improve existing analytical tools and introduce new methods for dynamic analysis of such system. According to the demand mentioned above, the research in the thesis is carried out based on the coupled dynamic characteristics of primary-secondary system, and the work includes 3 asepct of research content: seismic characteristics, numercical analysis method and seismic control strategy. The main findings of the research work are listed as follows:(1) The primay-secondary coupled system consisted of the nonlinear structure and secondary systems is established, and based on the dynamic coupling effect several important factors affecting the seismic response of secondary systems are studied, which is helpful for the estimating the seismic performance of secondary systems. The stochastic analysis model of primary-secondary system is established in the thesis, and the the coupling characteristics between the two subsystems are included, the corresponding parameters of the study include in the research: the random model corresponding to different types of ground site, the nonlinear situation of the structure, the model parameters of the nonlinear model, the postion of the secondary systems and dynamic interaction between multiple secondary systems.(2) The eccentric characteristic of the structure and multiple-dimensional seismic input ae considered and studied for the seismic response of secondary systems, and the effect of some important parameters are analyzed. The floor response spectrum of the eccentric structure to two horizontal earthquake input is also studied and some important parameters related with the floor response spectrum were also discussed, and the conventional method in the current aseismatic criterion is also discussed, consequently the shortcomings are indicated in the thesis.(3) Considering the dynamic coupling effect of the primary-secondary system, the united dynamic reliability of the primary-secondary system are computed and studied. In the thesis, firstly the necessity of the united dynamic reliability analysis of secondary system is explained, and then the calculation method is presented. By numerical research, the effect of parameters' varieties on the realiability of secondary systems is studied. Furthermore, the approximate solution based on the independent repeated trials and the exact solution based on general Rice formula are compared, and the research indicates that the approximate solution is inaccurate and conservative in some cases.(4) A new fast stochastic method for seismic analysis of the non-proportionally damped structure is presented, which can be used in the primary-secondary systems. In the new method, the dynamic equilibrium equation of non-proportionally damped structure is expressed in the iteration form, based on which the inverse operation of the matrices is avoided. Moreover, the new method also does not need the solution of any complex eigenvalue problem, in contrast to other methods found in the literature. The new method is based on fundamental principles from structural dynamics, pseudo excitation method and pseudo force method, so it is more efficient in computation and can give the exact solution. Furthermore, several numerical examples corresponding to different types of prmary-secondary systems are utilized to verify the accuracy and computational efficiency of the new method.(5) A new response spectrum combination rule for the seismic analysis of non-classically damped systems such as primary-secondary systems are developed. The approach, which is denoted the perturbation spectrum method, can provide a more accurate evaluation of non-classically damped system's mean peak response in terms of the ground response spectrum, and avoid the error introcued by ignoring the off-diagonal elements of modal damping matrix. Given the response spectrum which can possess statistical properties is often used in the current engineering design, the method has engineering application value. Finally, the computation efficiency and accuracy of the proposed method is examined by numerical examples.(6) A new strategy which can be used for the vibration absorbtion of multiple adjacent secondary systems is presented in the thesits. By setting viscous damper and shared mass damper connecting adjacent secondary systems, the vibration of all the systems can be reduced, and the corresponding numerical research are carried out. The parameters of the two measures are optimized for obtaining a good vibration control effect. In the paper, the effect of two strategies of STMD and VD on reducing the seismic response of secondary systems is studied and so is the application scope of the two seismic control strategies. Moreover, the author also gives the unified motion equations of the TMD and TLD, and proposes the modeling method to simulate TLD utilizing the TMD model, which can facilitate the model establishment of the tuned damper and has practical significance in engineering.