Seismic performance of isolation system of rolling friction with springs

In order to study an isolation system of rolling friction with springs, computer programs were compiled to evaluate the seismic performance based on its movement characteristics. Through the programs, the influences of various seismic performance factors, e.g., rolling friction coefficient, spring constant, were systematically investigated. Results show that by increasing the rolling friction coefficient, the structural relative displacement due to seismic load effectively decreases, while the structural response magnitude varies mainly depending on the correlations between the following factors: the spring constant, the earthquake intensity, and the rolling friction coefficient. Furthermore, increasing the spring constant can decrease the structural relative displacement, as well as residual displacement, however, it increases the structural response magnitude. Finally, based on the analyses of various seismic performance factors subjected to the scenario earthquakes, optimized theoretical seismic performance can be achieved by reasonably combining the spring constant and the rolling friction coefficient.

Engineering practice of seismic isolation and energy dissipation structures in China

The concepts of seismic isolation and energy dissipation structures emerged in the early 1970s.In China,the first seismic isolation structure was finished in 1993,and the first energy dissipation structure was built at about the same time.Up to 2007,China had more than 600 seismic isolation and about 100 energy dissipation building structures.In 2008,the huge Wenchuan earthquake hit the southwest of China,which triggered a bloom of new seismic isolation and energy dissipation structures.This paper presents the development history and representative applications of seismic isolation and energy dissipation structures in China,reviews the state-of-the-practice of Chinese design,and discusses the challenges in the future applications.Major findings are as follows:Basic design procedures are becoming standardized after more than ten years of experiences,which mainly involve determination of design earthquake forces,selection of ground motions,modeling and time-history analyses,and performance criteria.Nonlinear time-history analyses using multiple ground motions are the characteristic of the design of seismic isolation and energy dissipation structures.Regulations,standardization and quality control of devices,balance between performance and cost,comparison with real responses,and regular inspection are identified as the issues that should be improved to further promote the application of seismic isolation and energy dissipation structures in China.