| Summary: | 博士 === 國立臺灣科技大學 === 營建工程系 === 90 === ABSTRACT
In this study of soil-structure interaction (SSI) effects, the evaluation methods of dynamic impedance functions are extended to moderate and strong earthquake. Two issues, the soil behavior under medium and large ground strains and the influence depth below large area bases, are taken into consideration so that the results of SSI analysis of buildings are closer to the behavior under strong earthquake.
This study analyzes two buildings’ SSI effects, compares each building’s measured “RBR transfer functions” with its analyzed “RBR transfer functions”, and finds the influence depth of sway and rocking of base and the reduction of damping in the foundation vibration. The results of the two buildings, Teaching Building of I-Lan Agriculture and Engineering Institute and Construction Engineering Building of NTUST, find the influence depth of rectangular base and strip base are different. The verified result shows that the real damping of foundation vibration is 30% of the value calculated from conventional foundation vibration damping formula.
In order to extend the analysis process of SSI to designed earthquake (0.23g), the author analyzed 248 holes’ site response in Taipei basin. The results include: (1) designed acceleration time history in six zones, (2) shear modulus reduction and equivalent damping ratio of soil, (3) the threshold values of amplification and de-amplification effect. These results can be used to analyze SSI in designed earthquake.
Finally, ILAN building and TAIPW building are taken as examples to illustrate the SSI analysis procedure during designed earthquake. The ILAN Building has very strong SSI effects in each of the six zones of Taipei basin and its period lengthening ratio in zone 6 can reach 2.25; TAIPW building’s SSI effects in four zones are almost negligible. Because TAIPW building has resonance phenomenon in zone 2, base shear is particular amplified in zone 2. It is found from the simplified SSI analysis of different height buildings, the base shear of medium and low buildings are related to site soil properties and SSI effects. The dynamic behavior of very high buildings during earthquake are less influenced by SSI effects, but their base shears are highly effected by the characteristics of site condition.
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