Over the last two decades, vibration‐based structural health and condition monitoring has gradually become one of the main methods for monitoring changes in a structure on a global scale. This method has been applied to damage detection in many areas, including aerospace, mechanical and structural systems. However, it has not been widely used for identifying condition change of the structure itself. This paper demonstrates the feasibility of utilising acceleration and strain responses measured from a short‐span concrete culvert bridge located in New South Wales, Australia, to identify the effects of structural condition changes made to the deck due to bridge widening. In addition to the operating structural responses, two controlled traffic tests were carried out, before and after the bridge widening, in support of verifying the results from the modal analysis. A comparative study is presented evaluating the results obtained by two identification algorithms, namely, frequency‐domain decomposition (FDD) and frequency–spatial domain decomposition (FSDD), from which the link between the decrease in modal frequency and the event of bridge expansion as condition change is successfully established. The contribution of this work is to emphasise the application of FDD and FSDD on a short‐span concrete culvert bridge, in order to drive the interest from large‐scale bridges to short‐span bridges so as to increase the coverage of current bridge health monitoring.

中文翻译：

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利用振动响应进行混凝土涵洞状态监测的现场试验研究

在过去的二十年中，基于振动的结构健康状况监测已逐渐成为在全球范围内监视结构变化的主要方法之一。此方法已应用于许多领域的损坏检测，包括航空航天，机械和结构系统。但是，尚未广泛用于识别结构本身的状态变化。本文证明了利用从澳大利亚新南威尔士州的一座短跨混凝土涵洞桥测得的加速度和应变响应来确定由于桥梁加宽而引起的结构状况变化对甲板的影响的可行性。除了操作结构响应外，在桥梁拓宽前后，还进行了两次受控交通测试，支持验证模态分析的结果。提出了一项比较研究，评估了通过两种识别算法获得的结果，即频域分解（FDD）和频空间分解（FSDD），从中，模态频率降低与桥梁扩张事件之间的联系如下：条件更改成功建立。这项工作的目的是强调FDD和FSDD在短跨度混凝土涵洞桥梁上的应用，以引起人们对从大型桥梁到短跨度桥梁的兴趣，从而扩大当前桥梁健康监测的覆盖范围。频域分解（FDD）和频空域分解（FSDD），由此成功建立了模态频率的降低与条件变化引起的桥梁扩张事件之间的联系。这项工作的目的是强调FDD和FSDD在短跨度混凝土涵洞桥梁上的应用，以引起人们对大型桥梁到短跨度桥梁的兴趣，从而扩大当前桥梁健康监测的覆盖范围。频域分解（FDD）和频空间分解（FSDD），由此成功建立了模态频率的降低与条件变化引起的桥梁扩张事件之间的联系。这项工作的目的是强调FDD和FSDD在短跨度混凝土涵洞桥梁上的应用，以引起人们对大型桥梁到短跨度桥梁的兴趣，从而扩大当前桥梁健康监测的覆盖范围。