doi:10.3850/978-981-08-7920-4_S2-S79-cd

ABSTRACT

In order to improve the seismic performances of bridges, there is a concept of seismic design to ensure the structural performance against huge earthquake motion by allowing the local damages of sub-members which absorb seismic energy. This concept can be applied to an arch bridge if some lateral bracing members of the bridge have enough ductility, even though the seismic force may destroy them. However, the sub members, such as lateral bracings in an arch bridge usually cannot insure enough ductility after yielding, because the global or local buckling occurs under compressive forces. If the buckling of these members can be prevented, enough ductility can be assured. Then, in this study,we investigate ductility and energy absorption of an H-shaped member covered with a steel tube under different contact conditions, by conducting the nonlinear finite element analyses by using iso-parametric shell elements and a two-surface model as the constitutive law, and clarify the effects of ductility enhancement due to the restraint conditions by the steel tubes. Consequently, it is concluded that the global buckling prevention due to the covered tube certainly brings large improvement of ductility, moreover by changing cross sectional shape of the tube to restrain the local buckling of web and flanges, still larger ductility and energy absorption can be ensured.

Keywords: Seismic design, Ductility, Energy absorption, Contact problem, Two-surface model.

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