Abstract
A novel damage detection approach is proposed in this study for a continuous girder bridge in which support reaction influence lines (ILs) are adopted. First, the relationship between the local damage of a continuous girder bridge and a damage index, based on support reaction ILs, is established through analytical derivation. Subsequently, the sensitivity of a support reaction IL-based damage index is analyzed using Dempster-Shafer (D-S) evidence theory, and it shows that the support reaction IL-based damage index is more noise-resistant if more support reaction ILs from a variety of locations are used. Three case studies (a simple numerical study of a two-span continuous beam, a laboratory experimental study of a two-span aluminum beam, and a complicated numerical study of a continuous girder bridge in Xiamen) have been conducted to validate the effectiveness of the proposed method in different damage scenarios, including single damage and multiple damages. Satisfactory damage identification results can be obtained even in high-level measurement noise conditions, showing that the proposed approach offers a promising field detection technique for identifying local structural damages in continuous girder bridges.
Highlights
During the service period of a bridge structure over decades or even hundreds of years, the combined effects of environmental corrosion, material aging, long-term dynamic and static load effects, fatigue, and catastrophe will inevitably lead to the accumulation of structural damage and even possibly cause a catastrophic accident
To generate the mass function index, the central-difference approach was used to calculate the second derivative of the fitted influence lines (ILs) change, and the D-S evidence theory was applied to fuse multiple-sensor data
This paper proposed a novel damage-localization approach of a continuous girder bridge based on support reaction ILs
Summary
During the service period of a bridge structure over decades or even hundreds of years, the combined effects of environmental corrosion, material aging, long-term dynamic and static load effects, fatigue, and catastrophe will inevitably lead to the accumulation of structural damage and even possibly cause a catastrophic accident. This paper presents a novel damage localization approach of a continuous girder bridge by fusing noisy support reaction ILs. First, formula derivation establishes the relationship between the local damage of a two-span continuous beam and a support reaction ILs-based damage index. When a continuous beam is destroyed, the function will abruptly alter near the damaged area, and the original symmetry will be lost According to this characteristic of the support reaction IL, the change of the support reaction IL before and after damage is defined as the index of damage: ΔΦ ( x) = Φd ( x) − Φu ( x). The distance between two adjacent discrete points is represented by Δl , while the number of discrete points is represented by q
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