| At present, the damage levels to buildings after the earthquake are the main index of macroseismic intensity assessment in current seismic intensity scale, and other indexes are regarded as reference such as horizontal ground motion parameters. Now the Chinese Seismic Intensity Scale(CSIS 2008) has many advanced in compared with other intensity scales, but there are still some problems to be improved in the current assessment method of the intensity as follows.(1) The values of the ground motion parameters are in perfect accordance with that of CSIS 1980 during the past 30 years. However, the recent statistics empirical relationship between intensity values and strong ground motion parameters indicated that the correlation was poor in current relationship.(2) Due to the large update of building types in recent years in China, the large quantities of reinforced concrete building does not include the types of building in CSIS 2008. It brings certain difficulties to assess seismic intensity. Therefore, we need to study the rules of assessing seismic intensity for new types of buildings. Given all these, the dissertation shall regard mainly the relationships between seismic intensity and ground motion parameters, buildings damage levels as research objects to get down to research. The specific works and the corresponding to findings are summarized as follows:1. Put forward a new idea that the values of the ground motion parameters in CSIS 2008 are lower. We summarize the research achievements of the correlation between seismic intensity and peak ground motion parameters(such as peak ground acceleration / PGA and peak ground velocity / PGV values) in the domestic and abroad from 1904 to 2014. The research achievements then are divided into prophase, metaphase and anaphase results respectively to analyze statistically. The analysis results indicate that the PGA and PGV values are constantly enhancement as the intensity increases in the three phases. The tendency is that the increment is much more rapid in the early than that in the late. The PGA and PGV values of CSIS 2008 are lower than that of the recent phase.2. Developed new empirical relationships between the intensity values and PGA, PGV to use regression techniques. It has primarily been developed based on both instrumental ground motion parameters and macroseismic intensity from 97 earthqukes which occurred during the period of 1933-2014 in the domestic and abroad. On the basis of foundation data analysis and sorting in different backgrounds, using box plot to test outliers of data, regression analysis is set right on AHP weighted least squares method to obtain the relationship between intensity and PGA, PGV. We find that for PGA, PGV with Ⅴ≤ I ≤Ⅸ, I=3.73 log PGA-1.23, I=3.61 log PGV+2.72. The Intensity values predicted by the relationships are lower than that of CSIS 2008.3. Established assessing intensity codes for the new 2 building types, namely reinforced concrete frame houses and Chuandou wooden frame houses, amended assessing intensity codes for 3 building types in CSIS 2008, and given the mean damage index corresponding to intensity degrees for 5 building types. The building damage data is collected systematically for 112 earthquakes from 1976 to 2014, and it is sorted according to building types. Through statistical analysis, damage percentage, seismic vulnerable curves and mean damage index of 5 type buildings are proposed in intensity degrees and damage grades.4. Discussed the statistical methods to study the relationship between the intensity and ground motion parameters, and introduced machine learning methods to do statistical analysis. Assigning the regression effects of each method by standard mean square error, the results show that the ordinary least squares shall be used for statistical relationships between intensity and PGA, PGV, and that the nearest neighbor algorithm of machine learning shall be used for classified research between intensity and ground motion parameters. |
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