In this study, the oscillation behavior and aseismicity of a 4-span Rahmen bridge with a sliding type seismic isolation foundation are investigated using model vibration experiments and numerical simulation. Built on Type III ground, the bridge is erected to 1/10 scale with a sliding-type foundation that was made by separating the footing in the horizontal direction, whereas conventionally piers and foundation structures are rigidly linked together. Teflon (PTFE) was inserted between the separated sections as the sliding interface material. The study results show that a sliding-type seismic isolation foundation has a significant positive effect in decreasing responses during earthquakes and the experimental results can be explained by the dynamic analysis.
During the Chilean earthquakes of May, 1960, a number of tall, slender structures survived the ground shaking whereas more stable appearing structures were severely damaged. An analysis is made of the rocking motion of structures of inverted pendulum type. It is shown that there is a scale effect which makes tall slender structures more stable against overturning than might have been expected, and, therefore, the survival of such structures during earthquakes is not surprising.
We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero.