Effect of Damping Coefficients in Earthquakes Resistant Design with Viscous Dampers for Bridges

교량의 내진설계에 있어서 점성감쇠기능받침의 감쇠계수 영향평가

Viscous dampers have been utilized as bearings and STU`s (Shock Transmission Unit) in earthquake resistant designs for bridges. Some viscous dampers are used as energy dissipators on one hand, but some dampers such as STU`s are used as fixing devices during an earthquake on the other hand. This paper discusses the effect of viscous dampers on the response of bridge with respect to the magnitude of damping coefficients. For this purpose, a typical bridge was taken as an example, and time-history dynamic analysis have been carried out. The input seismic data used in the analyses are relevant to the response spectra in the Koreans design code. The results show that there is an optimum value of coefficient considered most effective in the design. A STU with a large value of coefficient seems to make its support fixed. The response of the bridge is not much sensitive to the variation of the damping coefficients.