Detection of debonding in steel-reinforced bridges using wavelet curvature features of laser-measured operating deflection shapes

Abstract

Hidden damage severely threatens the safety of structures due to its invisibility and indistinguishability. Debonding is typical hidden damage in steel-reinforced bridges. Detection of multiple debondings in steel-reinforced bridges poses a challenge for traditional nondestructive methods that require damage location as prior knowledge, but this condition is usually not satisfied for debonding located within the bridge. Differing from existing studies, this study explores a vibrational method of detecting multiple debondings needing no prior knowledge, that uses a scanning laser vibrometer to acquire densely-sampled operating deflection shapes of bridges. The operating deflection shape carries richer information than mode shapes for damage characterization. Nevertheless, densely-sampled deformed quantities are commonly susceptible to noise when used to identify damage. To detect multiple debondings, a new feature is developed, the wavelet-transform curvature operating deflection shape. This feature is used to identify multiple debondings in a steel-reinforced concrete slab dismantled from a bridge, clearly demonstrating the strengths of suppressing noise, intensifying the signatures of debonding, and requiring no prior knowledge of damage location. The proposed method holds promise for detecting multiple hidden damage in various structures besides bridges.

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

“…ODS-based damage detection techniques have been researched in the past for various different structures, including machines (Reilly, 2011), single-span bridges (Cao et al, 2017;de Siqueira & Nogueira, 2001;Xiang et al, 2013;Xu et al, 2013;Yoon et al, 2010;Zhang et al, 2013b), wind turbines (Zhang et al, 2013a), and gearboxes (Gade et al, 2009). Most of the proposed approaches aim to detect local damage such as cracks or debonding (Cao et al, 2017) using either ODS directly, or using ODS curvature (CODS) (Cao et al, 2017;Zhang et al, 2013b). In recent years, the use of wavelet transforms to estimate ODS and CODS has been investigated for crack detection in beam-like structures (Cao et al, 2017;Fitzgerald et al, 2019b;Hera & Hou, 2004;Hou et al, 2000;Xu et al, 2013;Zhu & Law, 2006).…”

“…Most of the proposed approaches aim to detect local damage such as cracks or debonding (Cao et al, 2017) using either ODS directly, or using ODS curvature (CODS) (Cao et al, 2017;Zhang et al, 2013b). In recent years, the use of wavelet transforms to estimate ODS and CODS has been investigated for crack detection in beam-like structures (Cao et al, 2017;Fitzgerald et al, 2019b;Hera & Hou, 2004;Hou et al, 2000;Xu et al, 2013;Zhu & Law, 2006).…”