Study On Soil-Structure Interaction On The Especial Site

Many results of SSI are presented thanks to researcher's effort in many countries. But a majority of these results is about the plain site. The effect of complex terrain to structure is comparatively lack of investigation. There is so much mountainous region in our homeland that many buildings are on especial site. Therefore the investigation about SSI of especial site is required. Most programs capable on analysis of site earthquake response don't include pre- and post-processing so that they can't be good at engineering practice. A secondary development applied to reinforce ANSYS with muli-transmitting boundary in order to be applicable to capable of analysis of site earthquake response. The calculated examples show that the method in this paper is reliable.The thesis analyses the frame on the inclined base-rock and the frame connected with ground by not only the first floor.Because the higher order frequencies changes to be close to the predominant frequency of the inputting wave owing to the frequencies reduced after taking SSI into account and the soil is likely to magnify the frequencies of wave near to the higher order frequencies of structure, the higher order modes of structure will more attach themselves to the motion. So there are two peak values in the Fourier spectrum and the distribution of earthquake response become saw tooth shape distribution. Because the inclined rock-base restrains the magnification of soil but changes little predominant frequency of soil, the inclined rock-base will restrain the response of structure and the distribution of earthquake response will be more near to linear but the shape will little change. The elastic modulus of the bank will largely affect the dynamical character of the frame connected with ground by not only the first floor. There are two influence factors on the frequencies of the frame connected with ground by not only the first floor. It is a trend to reduce the frequencies of the system when the bank becomes high and it is a trend to increase the frequencies when the number of floors is cut down. The second influence factor will be main when the elastic modulus of bank is big, and the first influence factor will be main when the elastic modulus of bank is small. The higher order frequencies will increase because of whiplash effect of the part of frame on the bank. This phenomenon will be more easily detected when the elastic modulus of bank is bigger. There will be more different between the frame connected with ground by not only the first floor and the general frame when the bank become higher or the number of spans below the bank became fewer. But the response of the frame connected with ground by not only first floor can be bigger or smaller than the general frame. It is bigger when the higher order frequencies of the input earthquake wave is more or when the elastic modulus of the bank is smaller and it is smaller when the higher order frequencies of the inputting earthquake motion is fewer or when the elastic modulus of the bank is bigger. The distribution of internal force will change when the rigidity of the bank.