Model vibration experiment of the seawater pipe duct in a nuclear power station

In the model vibration experiment in the duct structure buried underground, characteristic behaviors in the earth quake response on sectional plane were revealed. Vibration responses in the ground and the structure were examined for the different burying depths and input waves. So, in the non-linear region with ground shearing strain on 10-3 order, new information was obtained on the seismic load and the structure strain. (1) Acceleration response in the duct is little different from that in the ground. (2) Wall face shearing force and dynamic earth pressure are predominant in the vibration load. (3) The production mechanism of dynamic earth pressure is based on relative displacements of the ground and duct. (4) Because of the ground non-linear vibration, at large input levels the response is small as compared with the case of the linear response. (Mori, K.)