地震研究

为了提高震害预测和结构震后性能评估的准确性和合理性,提出了一种考虑断层距衰减的主余震序列构造方法,并使用该方法构造了50组相关场地的地震动; 以一座三跨连续梁桥为研究对象,使用OpenSees抗震分析软件进行非线性动力分析,采用改进的Park-Ang损伤指标建立易损性曲线,分析断层距对连续梁桥在不同设防主余震序列下的损伤指数和破坏概率的影响; 提出震后危险性分析方法,对比分析了考虑断层距的主余震序列对桥梁结构的震后风险性影响。结果表明:余震的发生导致结构的损伤概率提高了10倍以上; 在断层距10 km范围内的结构发生中度及以上破坏的风险性较大; 提高设防地震等级能有效避免结构在主余震序列作用下发生严重或倒塌破坏; 在震后救援和重建时考虑断层距的影响可以防止造成二次伤害。

To improve the accuracy and rationality of the seismic damage prediction and estimation of the post-earthquake structural performance,a mainshock-aftershock construction method considering the fault distance attenuation is proposed,and 50 sets of the ground motion are constructed using this method.A three-span,continuous beam bridge is selected as the sample.Nonlinear dynamic analysis is carried out using OpenSees software,and an improved Park-Ang damage index is used to establish the vulnerability curve.The influence of the fault distance on the damage index and failure probability of the continuous beam bridge at different fortification levels when hit by the mainshock-aftershock sequence is analyzed.A post-earthquake risk analysis method is proposed,and the impact of the mainshock-aftershock sequence on the seismic risk of bridge structures considering fault distance is compared and analyzed.The results show that the probability of structural damage increases tenfold with the occurrence of aftershocks.The risk of moderate or higher damage to structures within a fault distance of 10 km is relatively high.Increasing the aseismic fortification level can effectively prevent structures from serious or total collapse under the action of the main aftershock.The fault distance plays an important role in preventing the secondary damage in the post-earthquake rescue and reconstruction.

引言
1 主余震序列构造方法
2 桥梁风险分析的理论方法
3 工程概况及有限元模型
4 主余震序列作用下桥梁的风险性分析
5 结论

图1 余震震级衰减规律<br/>Fig.1 Attenuation law of the magnitude of aftershocks

图1 余震震级衰减规律
Fig.1 Attenuation law of the magnitude of aftershocks

表1 主余震事件信息<br/>Tab.1 Mainshock-aftershock event information

表1 主余震事件信息
Tab.1 Mainshock-aftershock event information

图2 本文构造的主余震序列<br/>Fig.2 Artificial mainshock-aftershock sequence

图2 本文构造的主余震序列
Fig.2 Artificial mainshock-aftershock sequence

表2 不同损伤状态对应的损伤指数范围(据Park,1987)<br/>Tab.2 The damage state corresponding to the damage index range(according to Park,1987)

表2 不同损伤状态对应的损伤指数范围(据Park,1987)
Tab.2 The damage state corresponding to the damage index range(according to Park,1987)

表3 不同破坏状态的损失比<br/>Tab.3 Loss ratios of different ultimate failure states

表3 不同破坏状态的损失比
Tab.3 Loss ratios of different ultimate failure states

图3 连续梁桥立面图<br/>Fig.3 Elevation figure of a continuous beam bridge

图3 连续梁桥立面图
Fig.3 Elevation figure of a continuous beam bridge

图4 主震作用下连续梁桥桥墩的损伤指数与PGA的回归分析<br/>Fig.4 Regression analysis between DI and PGA of the bridge piers subjected to the main shock

图4 主震作用下连续梁桥桥墩的损伤指数与PGA的回归分析
Fig.4 Regression analysis between DI and PGA of the bridge piers subjected to the main shock

图5 主震作用下连续梁桥桥墩的易损性曲线<br/>Fig.5 Vulnerability curve of the bridge piers hit by main shock

图5 主震作用下连续梁桥桥墩的易损性曲线
Fig.5 Vulnerability curve of the bridge piers hit by main shock

图6 不同断层距下桥墩的地震动加速度衰减曲线<br/>Fig.6 Attenuation of the ground motion acceleration at different fault distances

图6 不同断层距下桥墩的地震动加速度衰减曲线
Fig.6 Attenuation of the ground motion acceleration at different fault distances

图7 遭遇罕遇主震时不同断层距下桥墩的破坏概率<br/>Fig.7 The probability of damage to bridge piers at different fault distances during a rare major earthquake

图7 遭遇罕遇主震时不同断层距下桥墩的破坏概率
Fig.7 The probability of damage to bridge piers at different fault distances during a rare major earthquake

图8 多遇地震、罕遇地震、特罕遇地震作用下结构损伤指数随断层距的变化曲线<br/>Fig.8 The structural damage index vs the fault distance when the structure is hit by frequent earthquakes,rare earthquakes and very rare earthquakes

图8 多遇地震、罕遇地震、特罕遇地震作用下结构损伤指数随断层距的变化曲线
Fig.8 The structural damage index vs the fault distance when the structure is hit by frequent earthquakes,rare earthquakes and very rare earthquakes

图9 主余震序列作用下桥梁的破坏超越概率<br/>Fig.9 Exceeding probability of the bridge piers failure when piers are hit by the mainshock-aftershock sequence

图9 主余震序列作用下桥梁的破坏超越概率
Fig.9 Exceeding probability of the bridge piers failure when piers are hit by the mainshock-aftershock sequence

图10 场地的地震危险性曲线图<br/>Fig.10 The seismic hazard curve of the site

图10 场地的地震危险性曲线图
Fig.10 The seismic hazard curve of the site

图11 桥墩在各破坏状态下的危险性曲线<br/>Fig.11 Hazard curves for each damage state

图11 桥墩在各破坏状态下的危险性曲线
Fig.11 Hazard curves for each damage state

图12 特罕遇主余震序列作用下桥梁破坏的风险性概率<br/>Fig.12 Hazard probability of the bridge failure subjected to the very rare mainshock-aftershock sequence

图12 特罕遇主余震序列作用下桥梁破坏的风险性概率
Fig.12 Hazard probability of the bridge failure subjected to the very rare mainshock-aftershock sequence

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备注

引言

1 主余震序列构造方法

2 桥梁风险分析的理论方法

3 工程概况及有限元模型

4 主余震序列作用下桥梁的风险性分析

5 结论

期刊信息