基于被动激励的结构应变监测系统在线校准方法

针对在役桥梁结构应变监测系统全天时工况下的在线校准问题,提出了一种基于被动激励的在线校准方法,建立了在线校准系统模型。该模型以桥梁正常通行车辆的动态荷载为激励源,通过应变监测系统与参考系统对结构应变响应参量的同步测量,构建校准溯源链,实现在役应变监测系统不间断工作状态下的在线校准。根据结构应变监测系统计量性能评测需要,建立了基于大样本数据的期间测量误差、基本误差及置信区间的量化分析模型。依托广东九江大桥开展了试验验证,结果表明,所提方法具有现场实施的可行性,由不同数据集计算所得的在线校准结果一致性较好,在包含概率大于90%时,基本误差区间的半宽度偏差不大于±0.005。

On-line calibration method for structural strain monitoring system based on passive excitation

Aiming at the on-line calibration problem of in-service strain monitoring systems ( SMS) for bridge structures under all-day working conditions, an on-line calibration method based on passive excitation is proposed, and an on-line calibration system model is established. In this model, the dynamic load of normal passing vehicles on the bridge is used as the excitation source. Through synchronously measuring the structural strain response parameters of the SMS and the reference system, the traceability chain of calibration is constructed to realize the on-line calibration under the continuous working state of the in-service SMS. According to the requirements of the measurement performance evaluation of the SMS, a quantitative analysis model of period measurement error, basic error and confidence interval based on large sample data is established. Experiment verification was carried out on Jiujiang Bridge in Guangdong Province. The results show that the proposed method has feasibility for field implementation, and the on-line calibration results calculated from different data sets have good consistency. When the coverage probability is greater than 90% , the half-width deviation of the basic error interval is less than ±0. 005.