Study on Box Girder Damage Identification of Cable-Stayed Bridges

A comparative study of the girder damage identification of Jintang Cable-stayed Bridge in Zhoushan Island-Land Project using the deflection index, the cable tension index, the beam bottom bending stress index, the modal curvature index and the modal flexibility matrix is introduced. By means of finite element method, a series of damage cases associated with the box girder are analyzed. The result shows that, for different damage types, the best effect of the girder damage identification is the modal curvature index, followed by the cable tension index, the beam bottom bending stress index is nearly of the same effect as the modal flexibility matrix index, and the worst is the deflection index.

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A Novel Two-Stage Structural Damage Identification Method Based on Superposition of Modal Flexibility Curvature and Whale Optimization Algorithm

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455421501698 ◽

2021 ◽

pp. 2150169

Author(s):

Minshui Huang ◽

Xihao Cheng ◽

Zhigang Zhu ◽

Jin Luo ◽

Jianfeng Gu

Keyword(s):

Optimization Algorithm ◽

Damage Identification ◽

Whale Optimization Algorithm ◽

Two Stage ◽

Simply Supported ◽

Damage Location ◽

Flexibility Matrix ◽

Modal Flexibility ◽

Whale Optimization ◽

The Impact

A novel two-stage method is proposed to properly identify the location and severity of damage in plate structures. In the first stage, a superposition of modal flexibility curvature (SMFC) is adopted to locate the damage accurately, and the identification index of modal flexibility matrix is improved. The low-order modal parameters are used and a new column matrix is formed based on the modal flexibility matrix before and after the structure is damaged. The difference of modal flexibility matrix is obtained, which is used as a damage identification index. Meanwhile, based on SMFC, a method of weakening the “vicinity effect” is proposed to eliminate the impact of the surrounding elements to the damaged elements when damage identification is carried out for the plate-type structure. In the second stage, the objective function based on the flexibility matrix is constructed, and according to the damage location identified in the first stage, the actual damage severity is determined by the enhanced whale optimization algorithm (EWOA). In addition, the effects of 3% and 10% noise on damage location and severity estimation are also studied. By taking a simply supported beam and a four-side simply supported plate as examples, the results show that the method can accurately estimate the damage location and quantify the damage severity without noise. When considering noise, the increase of noise level will not affect the assessment of damage location, but the error of quantifying damage severity will increase. In addition, damage identification of a steel-concrete composite bridge (I-40 Bridge) under four damage cases is carried out, and the results show that the modified method can evaluate the damage location and quantify 5%–92% of the damage severity.

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Damage Identification of Plate Structure Based on the Method of Modal Flexibility Curvature Difference

MATEC Web of Conferences ◽

10.1051/matecconf/201925602015 ◽

2019 ◽

Vol 256 ◽

pp. 02015

Author(s):

Jiangang Zhao ◽

Yuxiang Zhang ◽

Jiazhao Chen

Keyword(s):

Numerical Analysis ◽

Lower Order ◽

Damage Identification ◽

Higher Order ◽

Plate Structure ◽

First Order ◽

Flexibility Matrix ◽

Damage Degree ◽

Higher Order Modes ◽

Modal Flexibility

According to the higher order modes of the structure are difficult to extract and the lower order are easy to obtain in practice, it is put forward that only uses the parameters of lower or first-order modal to constitute the modal flexibility curvature difference (MFCD) as the index of damage identification, which based on the flexibility matrix of structure being sensitive to the structure modal characteristics. Numerical analysis is made on different damage conditions of a plate structure, and the result shows that the MFCD can not only accurately identify the single-damage and multi-damage position of plate structure, but also reflect the size of damage degree. It has a great significance to apply the index into the range of damage identification of actual structures.

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Damage Identification Method of Beam Structure Based on Modal Curvature Utility Information Entropy

Advances in Civil Engineering ◽

10.1155/2020/8892686 ◽

2020 ◽

Vol 2020 ◽

pp. 1-20

Author(s):

Chang-Sheng Xiang ◽

Ling-Yun Li ◽

Yu Zhou ◽

Zi Yuan

Keyword(s):

Information Entropy ◽

Damage Identification ◽

Local Mode ◽

Beam Structure ◽

Damage State ◽

Entropy Index ◽

Damage Degree ◽

Curvature Index ◽

Modal Curvature ◽

Utility Information

Generally, the damage of the structure will lead to the discontinuity of the local mode shape, which can be well reflected by the modal curvature of the structure, and the local information entropy of the beam structure will also change with the discontinuity of the mode. In this paper, based on the information entropy theory and combining the advantages of modal curvature index in damage identification of beam structure, the modal curvature utility information entropy index is proposed. The modal curvature curves of nondestructive structures were obtained by fitting the modal curvature curves of damage structures with the gapped smoothing technique to avoid dependence on the baseline data of nondestructive structures. The index comprehensively reflects the damage state of the structure by calculating mutual weight change matrix and the weight-probability coefficient. The performance of the new index was verified by the finite element simulation and model test of simply supported beam, respectively. The results show that the modal curvature utility information entropy index takes advantage of the modal curvature index which is sensitive to damage and can overcome its shortcomings effectively. The index proposed can identify the damage location and damage degree accurately and has certain noise immunity, which provides an effective damage identification indicator for beam structures.

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Damage Detection of Continuous Box Girder Based on Modal Flexibility Curvature Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.671-674.1016 ◽

2013 ◽

Vol 671-674 ◽

pp. 1016-1020 ◽

Cited By ~ 1

Author(s):

Xiang Feng Xu ◽

Feng Zhang ◽

Wen Xin Zhu

Keyword(s):

Damage Detection ◽

Single Point ◽

Good Effect ◽

Box Girder ◽

Flexibility Matrix ◽

Displacement Mode ◽

Length Difference ◽

Modal Flexibility ◽

The Impact ◽

Detection Effect

The modal flexibility was more effective than structural frequency and displacement mode on damage detection of structures, it could be calculated easily based on low order mode of box girder. The damage detection method was proposed based on the modal flexibility curvature in this article, this indicator considered the impact of length difference of adjacent elements on modal flexibility matrix. Damage sensitivities of indicators is contrasted. Calculating results show that flexibility curvature difference has good detection effect on single point damage, multi-point damage and side element damage. The method in this article has good effect on damage detection of box girder.

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Modal Curvature and Modal Flexibility Methods for Honeycomb Damage Identification in Reinforced Concrete Beams

Procedia Engineering ◽

10.1016/j.proeng.2013.01.018 ◽

2013 ◽

Vol 51 ◽

pp. 119-124 ◽

Cited By ~ 25

Author(s):

V.B. Dawari ◽

G.R. Vesmawala

Keyword(s):

Reinforced Concrete ◽

Damage Identification ◽

Concrete Beams ◽

Reinforced Concrete Beams ◽

Modal Flexibility ◽

Modal Curvature

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FEM Free Damage Detection of Beam Structures Using the Deflections Estimated by Modal Flexibility Matrix

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455421501285 ◽

2021 ◽

pp. 2150128

Author(s):

Wen-Yu He ◽

Wei-Xin Ren ◽

Lei Cao ◽

Quan Wang

Keyword(s):

Damage Detection ◽

Structural Damage ◽

Damage Index ◽

Element Model ◽

Mode Shapes ◽

Beam Structures ◽

Flexibility Matrix ◽

Damage Quantification ◽

Modal Flexibility ◽

The Cost

The deflection of the beam estimated from modal flexibility matrix (MFM) indirectly is used in structural damage detection due to the fact that deflection is less sensitive to experimental noise than the element in MFM. However, the requirement for mass-normalized mode shapes (MMSs) with a high spatial resolution and the difficulty in damage quantification restricts the practicability of MFM-based deflection damage detection. A damage detection method using the deflections estimated from MFM is proposed for beam structures. The MMSs of beams are identified by using a parked vehicle. The MFM is then formulated to estimate the positive-bending-inspection-load (PBIL) caused deflection. The change of deflection curvature (CDC) is defined as a damage index to localize damage. The relationship between the damage severity and the deflection curvatures is further investigated and a damage quantification approach is proposed accordingly. Numerical and experimental examples indicated that the presented approach can detect damages with adequate accuracy at the cost of limited number of sensors. No finite element model (FEM) is required during the whole detection process.

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