Story Damage Identification of Irregular Buildings Based on Earthquake Records

2013 ◽  
Vol 29 (3) ◽  
pp. 963-985 ◽  
Author(s):  
Jer-Fu Wang ◽  
Chi-Chang Lin ◽  
Ging-Long Lin ◽  
Chun-Hao Yang
Keyword(s):  
Damage Assessment ◽  
Visual Inspection ◽  
Damage Identification ◽  
Damage Index ◽  
Analytical Formula ◽  
Mode Shapes ◽  
Severe Damage ◽  
Concrete Building ◽  
Damage Condition ◽  
Identification Techniques

In this paper, a story damage index was developed to evaluate the damage condition of a torsionally coupled building based on its dominant modal frequencies and mode shapes. This index has an analytical formula with a calculated value ranging from 0 (undamaged) to 1.0 (collapsed) to indicate the reduction of story lateral stiffness. The involved computation is simple once the modal parameters of any three modes are obtained through system identification techniques from few floor acceleration measurements. The damage region within a story can also be identified through tracking the change of eccentricity of center of rigidity. This index was verified by numerical simulations and a data analysis of the ASCE benchmark model. In addition, it was also applied to the damage assessment of a four-story reinforced concrete building in Taiwan, which experienced severe damage during the 2006 Taitung Beinan earthquake ( M = 6.2). The results agree fairly well with the visual inspection and show the applicability of the proposed damage assessment technique.

Structural Damage Assessment Using Output-Only Measurement: Localization and Quantification

2013 ◽  
Author(s):  
Chin-Hsiung Loh ◽  
Min-Hsuan Tseng ◽  
Shu-Hsien Chao
Keyword(s):  
Damage Detection ◽  
Damage Assessment ◽  
Structural Damage ◽  
Damage Identification ◽  
Model Updating ◽  
Null Space ◽  
Singular Spectrum Analysis ◽  
Damage Index ◽  
Computation Efficiency ◽  
Output Only

One of the important issues to conduct the damage detection of a structure using vibration-based damage detection (VBDD) is not only to detect the damage but also to locate and quantify the damage. In this paper a systematic way of damage assessment, including identification of damage location and damage quantification, is proposed by using output-only measurement. Four level of damage identification algorithms are proposed. First, to identify the damage occurrence, null-space and subspace damage index are used. The eigenvalue difference ratio is also discussed for detecting the damage. Second, to locate the damage, the change of mode shape slope ratio and the prediction error from response using singular spectrum analysis are used. Finally, to quantify the damage the RSSI-COV algorithm is used to identify the change of dynamic characteristics together with the model updating technique, the loss of stiffness can be identified. Experimental data collected from the bridge foundation scouring in hydraulic lab was used to demonstrate the applicability of the proposed methods. The computation efficiency of each method is also discussed so as to accommodate the online damage detection.

Non-model-based damage identification of plates using measured mode shapes

2016 ◽  
Vol 16 (1) ◽  
pp. 3-23 ◽  
Author(s):  
Yongfeng Xu ◽  
Weidong Zhu
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Damage Index ◽  
Thickness Reduction ◽  
Aluminum Plate ◽  
Mode Shapes ◽  
Identification Method ◽  
Model Based

Mode shapes (MSs) have been extensively used to detect structural damage. This paper presents a new non-model-based damage identification method that uses measured MSs to identify damage in plates. A MS damage index (MSDI) is proposed to identify damage near regions with consistently high values of MSDIs associated with MSs of different modes. A MS of a pseudo-undamaged plate can be constructed for damage identification using a polynomial of a properly determined order that fits the corresponding MS of a damaged plate, if the associated undamaged plate is geometrically smooth and made of materials that have no stiffness and mass discontinuities. It is shown that comparing a MS of a damaged plate with that of a pseudo-undamaged plate is better for damage identification than with that of an undamaged plate. Effectiveness and robustness of the proposed method for identifying damage of different positions and areas are numerically investigated using different MSs; effects of crucial factors that determine effectiveness of the proposed method are also numerically investigated. Damage in the form of a machined thickness reduction area was introduced to an aluminum plate; it was successfully identified by the proposed method using measured MSs of the damaged plate.

Damage Assessment of Seismically Excited Buildings Through Incomplete Measurements

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Chi-Chang Lin ◽  
Ging-Long Lin ◽  
Kun-Shu Hsieh
Keyword(s):  
Mode Shape ◽  
Damage Assessment ◽  
Degrees Of Freedom ◽  
Information Matrix ◽  
Damage Index ◽  
Mode Shapes ◽  
Numerical Verification ◽  
Earthquake Excitation ◽  
Practical Applications ◽  
Identification Technique

Measuring responses at all degrees of freedom (DOF) of a real structure is impossible and impractical when few sensors are available. This study presents a damage-assessment technique for seismically excited buildings using only a few floor-response measurements. In the first step, the system realization using information matrix (SRIM) identification technique was applied to estimate such modal properties as frequencies and damping ratios of an instrumented building. However, the complete mode shapes cannot be acquired due to a lack of comprehensive measurements. A novel optimal mode-shape-recovery (OMSR) technique was applied to reconstruct the complete first mode shape of the building system. An optimization process was then applied to minimize a prescribed objective function that represents the difference between measured and estimated outputs at instrumented locations. A story damage index (SDI) computed using the first mode shape recovered was applied to determine the degree of story damage. Noisy floor measurements of a five-story shear building under earthquake excitation were utilized for numerical verification. Moreover, a three-story benchmark building was analyzed to assess the accuracy and applicability of the proposed OMSR technique via experimental data. The proposed method obtained results in fairly good agreement with those of full measurements and is of value in practical application. The damage-assessment results obtained with the proposed method agree well with the actual damage, demonstrating that the proposed method is suitable for practical applications.

scholarly journals Novel TQWT Algorithm for Structural Damage Identification

2019 ◽  
Vol 8 (4) ◽  
pp. 5136-5146
Keyword(s):  
Input Signal ◽  
Structural Damage ◽  
Damage Identification ◽  
Damage Index ◽  
Identification Problem ◽  
Oscillatory Behavior ◽  
Mode Shapes ◽  
Q Factor ◽  
Stiffness Loss ◽  
Beam Damage

In this paper tunable Q-factor wavelet transform is implemented into damage identification. Fixed – Fixed beam damage identification problem is demonstrated. Translation and Rotational mode shapes are used as an input signal, the TQWT algorithm depends Q-factor and asymptotic redundancy, when it matches with the oscillatory behavior of the input signal it is tuned. This method decomposes a signal into a high-Q-factor and low-Q-factor component, and it can be used to differentiate the damaged and undamaged mode shapes of the beam structure. TQWT coefficient is used as damage index to locate and quantify the damage. Proposed method evaluated experimentally and results shows TQWT algorithm has a potential to detect even a small damage (10% stiffness loss) present in the structure.

scholarly journals Remote Sensing Based Rapid Assessment of Flood Crop Damage Using Novel Disaster Vegetation Damage Index (DVDI)

2020 ◽  
Author(s):  
Md. Shahinoor Rahman ◽  
Liping Di ◽  
Eugene Yu ◽  
Li Lin ◽  
Zhiqi Yu
Keyword(s):  
Crop Yield ◽  
Damage Assessment ◽  
Yield Loss ◽  
Damage Index ◽  
Crop Damage ◽  
Flood Events ◽  
Severe Damage ◽  
Severe Storms ◽  
Crop Yield Loss ◽  
Vegetation Damage

Abstract Accurate crop-specific damage assessment immediately after flood events is crucial for grain pricing, food policy, and agricultural trade. The main goal of this research is to estimate the crop-specific damage that occurs immediately after flood events by using a newly developed Disaster Vegetation Damage Index (DVDI). By incorporating the DVDI along with information on crop types and flood inundation extents, this research assessed crop damage for three case-study events: Iowa Severe Storms and Flooding (DR 4386), Nebraska Severe Storms and Flooding (DR 4387), and Texas Severe Storms and Flooding (DR 4272). Crop damage is assessed on a qualitative scale and reported at the county level for the selected flood cases in Iowa, Nebraska, and Texas. More than half of flooded corn has experienced no damage, whereas 60% of affected soybean has a higher degree of loss in most of the selected counties in Iowa. Similarly, a total of 350 ha of soybean has moderate to severe damage whereas corn has a negligible impact in Cuming, which is the most affected county in Nebraska. A total of 454 ha of corn are severely damaged in Anderson County, Texas. More than 200 ha of alfalfa have moderate to severe damage in Navarro County, Texas. The results of damage assessment are validated through the NDVI profile and yield loss in percentage. A linear relation is found between DVDI values and crop yield loss. An R2 value of 0.54 indicates the potentiality of DVDI for rapid crop damage estimation. The results also indicate the association between DVDI class and crop yield loss.

scholarly journals Baseline-Free Structural Damage Identification for Beam-Like Structures Using Curvature Waveforms of Propagating Flexural Waves

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2453
Author(s):  
Y. F. Xu ◽  
J. S. Kim
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Damage Index ◽  
Mode Shapes ◽  
Experimental Investigations ◽  
High Signal ◽  
Flexural Waves ◽  
Local Regression ◽  
Local Effects ◽  
Structural Damage Identification

Curvatures in mode shapes and operating deflection shapes have been extensively studied for vibration-based structural damage identification in recent decades. Curvatures of mode shapes and operating deflection shapes have proved capable of localizing and manifesting local effects of damage on mode shapes and operating deflection shapes in forms of local anomalies. The damage can be inversely identified in the neighborhoods of the anomalies that exist in the curvatures. Meanwhile, propagating flexural waves have also been extensively studied for structural damage identification and proved to be effective, thanks to their high damage-sensitivity and long range of propagation. In this work, a baseline-free structural damage identification method is developed for beam-like structures using curvature waveforms of propagating flexural waves. A multi-resolution local-regression temporal-spatial curvature damage index (TSCDI) is defined in a pointwise manner. A two-dimensional auxiliary TSCDI and a one-dimensional auxiliary damage index are developed to further assist the identification. Two major advantages of the proposed method are: (1) curvature waveforms of propagating flexural waves have relatively high signal-to-noise ratios due to the use of a multi-resolution central finite difference scheme, so that the local effects of the damage can be manifested, and (2) the proposed method does not require quantitative knowledge of a pristine structure associated with a structure to be examined, such as its material properties, waveforms of propagating flexural waves and boundary conditions. Numerical and experimental investigations of the proposed method are conducted on damaged beam-like structures, and the effectiveness of the proposed method is verified by the results of the investigations.

scholarly journals Development of a Novel Damage Detection Framework for Truss Railway Bridges Using Operational Acceleration and Strain Response

Vibration ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 422-445
Author(s):  
Md Riasat Azim ◽  
Mustafa Gül
Keyword(s):  
Damage Detection ◽  
Damage Identification ◽  
Numerical Study ◽  
Damage Index ◽  
Strain Analysis ◽  
Time History ◽  
Principal Component ◽  
Element Model ◽  
Railway Bridges ◽  
Truss Bridge

Railway bridges are an integral part of any railway communication network. As more and more railway bridges are showing signs of deterioration due to various natural and artificial causes, it is becoming increasingly imperative to develop effective health monitoring strategies specifically tailored to railway bridges. This paper presents a new damage detection framework for element level damage identification, for railway truss bridges, that combines the analysis of acceleration and strain responses. For this research, operational acceleration and strain time-history responses are obtained in response to the passage of trains. The acceleration response is analyzed through a sensor-clustering-based time-series analysis method and damage features are investigated in terms of structural nodes from the truss bridge. The strain data is analyzed through principal component analysis and provides information on damage from instrumented truss elements. A new damage index is developed by formulating a strategy to combine the damage features obtained individually from both acceleration and strain analysis. The proposed method is validated through a numerical study by utilizing a finite element model of a railway truss bridge. It is shown that while both methods individually can provide information on damage location, and severity, the new framework helps to provide substantially improved damage localization and can overcome the limitations of individual analysis.

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