Wavelet-based operating deflection shapes for locating scour-related stiffness losses in multi-span bridges

Abstract

Wavelet-based operating deflection shapes for locating scourrelated stiffness losses in multi-span bridges, Structure and Infrastructure Engineering,

Indirect Monitoring of Frequencies of a Multiple Span Bridge Using Data Collected from an Instrumented Train: A Field Case Study

“…While this type of monitoring has been seen to be effective, it requires a distribution of sensors along the length of the bridge, that consumes a lot of cost and labour. For longer multiple span bridges in particular, traditional methods of monitoring can become difficult and costly, since they require more sensors [ 4 , 11 , 12 ].…”

“…Many studies have estimated natural frequencies from acceleration responses obtained using numerical models [ 15 ] as well as bridge field measurements in a form of free vibration [ 16 ], forced vibration [ 14 , 17 ], or ambient vibration [ 18 ]. The natural frequencies are considered as some of the key damage detection features for these studies and have provided reasonable results for the detection of both local [ 19 , 20 ] and global damage [ 11 , 21 , 22 , 23 ]. Although, natural frequencies are not considered to be ideal, because of their low-sensitivity to damage [ 3 , 24 ], changes in the natural frequencies and modal properties have been used to detect scour damage in multiple span structures [ 5 , 11 , 25 , 26 ] and longer span bridges [ 27 ].…”

“…The natural frequencies are considered as some of the key damage detection features for these studies and have provided reasonable results for the detection of both local [ 19 , 20 ] and global damage [ 11 , 21 , 22 , 23 ]. Although, natural frequencies are not considered to be ideal, because of their low-sensitivity to damage [ 3 , 24 ], changes in the natural frequencies and modal properties have been used to detect scour damage in multiple span structures [ 5 , 11 , 25 , 26 ] and longer span bridges [ 27 ]. The significant impact of a scour-hole at the foundation has been shown to affect the entire bridge response [ 11 , 28 ].…”

“…Although, natural frequencies are not considered to be ideal, because of their low-sensitivity to damage [ 3 , 24 ], changes in the natural frequencies and modal properties have been used to detect scour damage in multiple span structures [ 5 , 11 , 25 , 26 ] and longer span bridges [ 27 ]. The significant impact of a scour-hole at the foundation has been shown to affect the entire bridge response [ 11 , 28 ]. In numerical [ 11 ], and laboratory setups [ 26 ] for multiple span bridges, the impact of damage on each span’s natural frequency is found to be reasonable, that can be understood using advanced frequency-domain-based [ 29 ] or mode-shape-based methods [ 4 , 5 ].…”

Operational Deflection Shapes Magnification and Visualization Using Optical-Flow-Based Image Processing

“…Although ODS are not exactly MS, as ODS are a linear combination of MS, they are commonly used when identifying MS are difficult or impossible. ODS have a number of applications in civil engineering [12], industrial rotary machinery [13] and transportation [14]. To obtain an ODS, a simultaneous measurement of vibration responses at a number of locations is required.…”