Long‐term performance of existing bridge structures provides stakeholders with information that facilitates decision making for reasonable and optimal maintenance and management. The neutral axis (NA) is a potentially reliable and robust indicator to evaluate bridge performance since it depends on the loss of elastic modulus or effective sectional area. In this study, the NA indicator is defined and derived, and it is combined with the statistical characteristics of the NA distribution, to assess long‐term structural performance. A systematic long‐term performance assessment framework based on NA is also proposed. The NA is estimated from strain measurements and related practical signal processing methods. To validate the proposed framework, strain signals acquired from a preinstalled structural health monitoring system on an existing concrete beam bridge were analyzed. For the long‐term performance assessment, an NA database was established. The statistical characteristics of the NA sample in the daily evaluation cycle were obtained to evaluate the performance. The results show that different cross sections have their own estimated NA; and during the monitoring period, the NA indicators fluctuate within a reasonable range. With the increase of monitoring data, these results can be continually updated. It can be concluded that the proposed NA indicator, along with the related framework, can be employed effectively in the condition assessment of concrete box girder bridges for long‐term health monitoring.

中文翻译：

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使用中性轴指示器对混凝土梁桥进行长期性能监测和评估

现有桥梁结构的长期性能为利益相关者提供了有助于决策的信息，以进行合理，最佳的维护和管理。中性轴（NA）是评估桥梁性能的潜在可靠且可靠的指标，因为它取决于弹性模量或有效截面积的损失。在这项研究中，NA指标被定义和推导，并与NA分布的统计特征相结合，以评估长期结构性能。还提出了一个基于NA的系统的长期绩效评估框架。NA是根据应变测量和相关的实际信号处理方法估算的。为了验证提议的框架，分析了从现有混凝土梁桥上预安装的结构健康监测系统获取的应变信号。为了进行长期绩效评估，建立了一个NA数据库。获得了每日评估周期中NA样本的统计特征以评估性能。结果表明，不同的横截面都有自己的估计NA。在监测期内，NA指标在合理范围内波动。随着监视数据的增加，这些结果可以不断更新。可以得出结论，建议的NA指标以及相关框架可以有效地用于混凝土箱梁桥的状态评估，以进行长期健康监测。建立了NA数据库。获得了每日评估周期中NA样本的统计特征以评估性能。结果表明，不同的横截面都有自己的估计NA。在监测期内，NA指标在合理范围内波动。随着监视数据的增加，这些结果可以不断更新。可以得出结论，建议的NA指标以及相关框架可以有效地用于混凝土箱梁桥的状态评估，以进行长期健康监测。建立了NA数据库。获得了每日评估周期中NA样本的统计特征以评估性能。结果表明，不同的横截面都有自己的估计NA。在监测期内，NA指标在合理范围内波动。随着监视数据的增加，这些结果可以不断更新。可以得出结论，建议的NA指标以及相关框架可以有效地用于混凝土箱梁桥的状态评估，以进行长期健康监测。NA指标在合理范围内波动。随着监视数据的增加，这些结果可以不断更新。可以得出结论，建议的NA指标以及相关框架可以有效地用于混凝土箱梁桥的状态评估，以进行长期健康监测。NA指标在合理范围内波动。随着监视数据的增加，这些结果可以不断更新。可以得出结论，建议的NA指标以及相关框架可以有效地用于混凝土箱梁桥的状态评估，以进行长期健康监测。