Structural Robustness-based SHM Point Arrangement Strategy for In-service Cable-stayed Bridge Subjected to Cable Damage Effect

In-service bridge safety accidents occur occasionally, especially for the structures after a long-term service. One example is the cable-stayed bridge, a common high order statically indeterminate structure usually designed with multiple components. Affected by natural environment (e.g., temperature) and fatigue factor, the stay cable is more vulnerable to suffer different damage effects (e.g., corrosion) and should be monitored over time. However, a large number of structural health monitoring (SHM) sensors are usually arranged with consideration of traditional methods (e.g., full-scale load test). A detailed analysis on the structural robustness of in-service bridge subjected to different damage effects is also urgently needed. The vulnerable part or component can then be located as SHM point for a long-term monitoring. As a part of a series of study, this study focuses on the structural robustness-based SHM point arrangement of in-service cable-stayed bridge subjected to cable failure. A general technical process of the SHM point arrangement strategy of in-service bridge is proposed firstly. The evaluation index of structural robustness and the typical characteristic of in-service bridge are introduced firstly. An in-service cable-stayed bridge is then taken as a case study. The finite element (FE) analysis model is established. A detailed comparison and verification is also performed with consideration of previous studies. This study indicates that a general similar trend can be observed for the structural robustness of in-service cable-stayed bridge. The elements with smaller structural robustness of the main girder of this kind of bridge are basically located around the cross section at auxiliary pier. The next is the cross section around the middle part of middle span and side span. Thus, the SHM point should be generally arranged at around the cross section at the auxiliary pier firstly, and the next is around the middle span and side span. Moreover, the longer stay cable should also be located as SHM point or at least be worthy of our attention. With consideration of financial funding factor and other specific requirements, a higher proportion of the elements of main girder and stay cable can be further arranged as the SHM points for a long-term monitoring. This study can make us a better understanding of the structural robustness of in-service cable-stayed bridge. The SHM point arrangement of this kind of bridge can be more targeted, and the number of SHM sensors can also be greatly reduced.