基于城市抗震弹塑性分析的我国主要城市建筑地震风险评估

全国尺度的城市建筑地震风险评估对城市防震减灾工作有着重要意义。本文根据全国人口普查和城市统计年鉴等给出的宏观指标建立城市建筑数据库,通过GEAR1方法(Global earthquake activity rate model 1)和第五代中国地震动参数区划图给出具体场地的地面运动强度,通过地面坡度与剪切波速的对应关系确定的场地类别来考虑地震动输入,采用城市抗震弹塑性分析方法建立建筑分析模型,通过地震经济损失风险指标和建筑严重破坏和倒塌风险作为风险评价指标,给出中国大陆主要城市建筑地震风险分布图。结果分析表明,本文方法可以基于可公开获取的数据预测全国不同城市的建筑震害风险;根据第五代地震动参数区划图给出的地面强度,地震经济损失高风险区主要是设防加速度0.3g以上地区;考虑城市人口、GDP因素后,中、东部城市因人口和财富密度较高,建筑地震风险增加明显;不同地震动选波对经济损失风险影响较小,而对倒塌风险影响较大。本文分析方法可以为城市建筑地震风险分析提供相关参考。

Seismic Risk Assessment of Buildings in Major Chinese CitiesBased on the Nonlinear Time-history Analysis of Cities

It is of profound significance to assess the national-scale seismic risk of urban buildings for seismic disaster prevention and mitigation. the nonlinear time-history analysis of cities, building seismic risk assessment of mainland cities was conducted in this work. First, the urban buildings database was established according to the macroscopic indicators provided by the Nationwide Census and China City Statistical Yearbook. Then, ground motion intensities of the specific sites was obtained from the Global Earthquake Activity Rate Model 1 (GEAR1) method and the 5th seismic ground motion parameters zonation map of China. Then, site classifications of the cities were obtained using the corresponding relationship between the ground slope and the shear wave velocity, through which the ground motion input could be further determined. Finally, based on the dynamic elastoplastic analysis of urban buildings, the seismic economic loss risk and extensive damage and collapse risk were assessed. Using the methods cited above, a map of building seismic risk of mainland cities is given. The results showed that:(1) the method proposed in this work can assess the building seismic risk of mainland cities based on the publicly available data; (2) high seismic economic loss risk regions are mainly located in areas where the intensity of design-based earthquakes given by the 5th seismic ground motion parameters zonation map of China is more than 0.3g; (3) after consideration of urban population and GDP, the building seismic risk of the eastern and central cities will increase significantly due to higher density of population and wealth; (4) differently-selected ground motions have little impact on the seismic economic loss risk but has a greater impact on the extensive damage and collapse risk. The outcomes of this work can provide a useful method for future works on building seismic risk assessment of mainland cities.