| Summary: | 碩士 === 國立暨南國際大學 === 土木工程學系 === 91 === After collecting borehole data of the Pu-Li basin, the seismic ground response results, such as ground acceleration contour and the predominant period contour, were obtained in this research. The reason why those buildings in Pu-Li basin destroyed in the chi-chi earthquake was also discussed.
In the first, 121 borehole data of Pu-Li basin were collected and used to define soil layers and the geotechnical microzonation of the Pu-Li downtown area. According to the difference of soil depositions and the literary records, the influence of two inferred faults to the damage of buildings in Pu-Li downtown area under chi-chi earthquake was proposed. Secondary, the predominant periods of studied site were calculated by the simplified method. The results were verified with the CEDAMS databank. It was found that the best predominant periods of Pu-Li downtown area were predicted by using the shear wave velocities estimated from SPT-N values as well as a simplified method recommended by code.
Two prediction equations for the shear wave velocities in gravel layers of Pu-Li basin were proposed in this study. AS well as the soil dynamic properties shown in the literatures, these shear wave velocities and the geotechnical microzonations of the Pu-Li downtown area were used to input into SHAKE91 to calculate the seismic ground response. Sixty sites with reliable borehole data as well as the acceleration record (TCU074) of Nan-Kung elementary school during chi-chi earthquake were employed to define the ground acceleration contour map and the predominant period contour map for the Pu-Li downtown area. For acceleration, it is found that the estimated largest PGA (0.84G) is about near the Pu-Li town hall. This result is very close to the damages situation of the Pu-Li downtown area in Chi-Chi earthquake. It is concluded that the research result of this study is evidently adequate for predicting the damage conditions of Pu-Li downtown area under Chi-Chi earthquake.
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