基于结构动力响应的小波包能量谱提出了两种结构损伤预警指标:能量比偏差和能量比方差。以润扬长江大桥北汊斜拉桥为研究对象,分析了损伤预警指标在不同损伤位置、损伤程度和测量噪声水平下的预警能力。研究结果表明:与结构自振频率等模态参数相比,能量比偏差和能量比方差可以明显提高大跨桥梁结构损伤预警的敏感性和有效性,并且具有良好的抗噪声干扰能力。能量比偏差和能量比方差可作为大跨桥梁结构损伤预警系统的损伤预警指标。
Two structural damage alarming indices including energy ratio deviation (ERD) and energy ratio variance (ERV) were put forward based on wavelet packet energy spectrum decomposed from the structural dynamic responses. For the Runyang Yangtze Cable-Stayed Bridge, the alarming capacity of two damage alarming indices was discussed with respect to damage location, damage extent and measurement noise. The simulation results compared with modal parameters, such as natural frequency reveal that damage alarming indices ERD and ERV can improve the sensitivity and effectiveness of damage alarming for long-span bridges together with preferable noise robusticity, which can be used for structural damage alarming of long-span bridges.