A Study of the Intensity Index of the Strong Ground Motions that Property Evaluates the Seismic Damage of Structures

结构的地震破坏取决于地震动的特性，如烈度和谱，以及结构的质量，如自振周期和阻尼比。针对目前还没有一种有效的强地震动烈度指标来评估结构在大范围的自振周期内的地震破坏，提出了修正的最大地震动冲量，定义为最大地震动冲量与峰值加速度和结构自振周期的乘积的最小值。利用日本、美国和台湾地区记录的73个峰值加速度几乎都大于3 m/s/s的强震记录，通过时程分析，分析了层间恢复特性为双线性模型的单层、三层、五层和七层结构的破坏与几种措施的关系。结构的损伤度量是用与各层延性系数最大值相关的第一层屈服剪力来度量，修正的最大冲量是评价结构损伤的最有效的指标，而峰值地面加速度、峰值地面速度第一固有周期0.1 ~ 1.0秒的速度谱和谱强度。修正后的最大冲量与屈服剪力之间的相关系数大于0.8，与延性系数2.0或5.0相关。结果表明，修正的最大冲量是时程分析中强震动烈度水平选取的最有效的方法。

The seismic damage of structures depends on the characteristics of seismic motions, such as intensity and spectrum, and structural qualities, such as the natural period and the damping ratio. There was no effective intensity measure of the strong ground motions that adequately evaluates seismic damage of structures in the wide range of the natural periods.We propose the modified maximum impulse defined as the minimum value of the maximum impulse in strong ground motion and the product of the peak ground acceleration and quarter of the natural period of a structure. The relationship between several measures and the damage of single story, three stories, five stories and seven stories structures which story restoring characteristics are bilinear model is analyzed by the time history analysis using seventy three strong ground motions that are recorded in Japan, United States and Taiwan which peak ground accelerations are almost greater than 3 m/s/s. The damage measure of a structure is used the yield shear force in the first story that related to the maximum ductility factor in the all stories.The modified maximum impulse is the most effective measure that evaluates the damage of structures than other measures, such as the peak ground acceleration, the peak ground velocity, the velocity spectrum and the spectral intensity in the first natural period from 0.1 second to 1.0 second. The correlation coefficients between the modified maximum impulse and the yield shear force that is related to the ductility factor of 2.0 or 5.0 is greater than 0.8. This result shows that the modified maximum impulse is the most effective measure for the selection of intensity level of the strong motion in the time history analysis.