scholarly journals Study on the Correlation of Vibration Properties and Crack Index in the Health Assessment of Tunnel Lining

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Xuezhen Wu ◽  
Yujing Jiang ◽  
Kusaba Masaya ◽  
Tetsuya Taniguchi ◽  
Takahide Yamato
Keyword(s):  
Visual Inspection ◽  
Health Assessment ◽  
Tunnel Lining ◽  
New Method ◽  
Ambient Vibration ◽  
Ambient Vibration Test ◽  
Inspection Method ◽  
Vibration Properties ◽  
Average Spectrum ◽  
Crack Index

This paper examines the correlation of vibration properties and crack index of tunnel lining in evaluating risk of collapsing. The visual inspection method, which was widely used, was not reliable enough as the stability of tunnel lining was influenced by the voids and the cracks that were invisible. A new method for the health assessment of tunnel lining was proposed, which can evaluate the whole structural condition according to the vibration properties of tunnel lining. A series of field tests were conducted to evaluate the validity of this new method and to make a comparative analysis with the visual inspection test results. The resultant average spectrum (RAS) of tunnel lining was identified according to the acceleration data of ambient vibration test of Hidake Tunnel in Japan. The tunnel lining crack index (TCI) was also obtained by digital visual inspection test. The correlation between the vibration characteristics and the crack index of tunnel lining was confirmed. However, the voids and the cracks on the inside of the lining were neglected in visual inspection test, which could pose a serious threat to tunnel safety. The vibration measurements by seismometer are an effective way to evaluate the global stability of tunnel lining.

scholarly journals A New Health Assessment Index of Tunnel Lining Based on the Digital Inspection of Surface Cracks

2017 ◽  
Author(s):  
Xuezhen Wu ◽  
Yujing Jiang ◽  
Jianhua Wang ◽  
Kusaba Masaya ◽  
Tetsuya Taniguchi ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Visual Inspection ◽  
Crack Density ◽  
Health Assessment ◽  
Tunnel Lining ◽  
New Method ◽  
Inspection Method ◽  
Assessment Index ◽  
Comparative Tests ◽  
The Stability

The stability assessment of aged tunnel linings were mainly evaluated based on the visual inspection, and the Tunnel-lining Crack Index (TCI) is one of the most widely used tunnel lining health assessment indexes in Japan. However, the intersection and distribution of cracks, which can influence the stability of tunnel lining greatly, were not considered in the TCI. A new method was proposed for the health assessment of tunnel lining, which evaluate the lining states according to the fractal dimension of cracks. Based on the machine vision-based method, the crack image can be extracted efficiently. The fractal dimension of lining cracks in one span can be obtained in a few minutes. A series of comparative tests and field tests were conducted to evaluate the validity of this new method. The comparative tests confirmed that fractal dimension can characterize the density, width, and distribution of cracks. The results also certificated that the influence of crack width is larger than the crack density. The intersection of cracks, which will increase the risk of lining collapse, can also increase the fractal dimension, whereas the TCI keep constant. The fractal dimensions of tunnel lining cracks were obtained according to the digital inspection test of Hidake Tunnel in Japan for all the 65 spans. Moreover, the TCI was obtained through statistical methods. The correlation between fractal dimension and TCI of tunnel lining was studied. The significance of the new evaluation index is that it can identify some unusual spans of tunnel lining and provide a basis for further internal testing. As a complement to the conventional visual inspection method, the fractal dimension of the cracks is a promising health assessment index.

scholarly journals Ambient Vibration Tests of an Arch Dam with Different Reservoir Water Levels: Experimental Results and Comparison with Finite Element Modelling

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Sergio Vincenzo Calcina ◽  
Laura Eltrudis ◽  
Luca Piroddi ◽  
Gaetano Ranieri
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Water Levels ◽  
Arch Dam ◽  
Experimental Results ◽  
Ambient Vibration ◽  
Reservoir Water ◽  
Ambient Vibration Tests ◽  
Vibration Properties ◽  
Vibration Tests

This paper deals with the ambient vibration tests performed in an arch dam in two different working conditions in order to assess the effect produced by two different reservoir water levels on the structural vibration properties. The study consists of an experimental part and a numerical part. The experimental tests were carried out in two different periods of the year, at the beginning of autumn (October 2012) and at the end of winter (March 2013), respectively. The measurements were performed using a fast technique based on asynchronous records of microtremor time-series. In-contact single-station measurements were done by means of one single high resolution triaxial tromometer and two low-frequency seismometers, placed in different points of the structure. The Standard Spectral Ratio method has been used to evaluate the natural frequencies of vibration of the structure. A 3D finite element model of the arch dam-reservoir-foundation system has been developed to verify analytically determined vibration properties, such as natural frequencies and mode shapes, and their changes linked to water level with the experimental results.

Ambient vibration test results of the Imperial County Services Building

1983 ◽  
Vol 73 (6A) ◽  
pp. 1895-1902
Author(s):  
Gerard C. Pardoen
Keyword(s):  
Strong Motion ◽  
Ambient Vibration ◽  
Vibration Test ◽  
Test Results ◽  
Structural Failure ◽  
Imperial Valley ◽  
Ambient Vibration Test ◽  
Significant Interest ◽  
First Time ◽  
County Services

Abstract The ambient vibration test results conducted on the Imperial County Services Building prior to the 15 October 1979 Imperial Valley earthquake are summarized. These results are of significant interest because the Imperial County Services Building has been the source of many postearthquake investigations due to the fact that the 1979 earthquake represented the first time a building instrumented with strong motion recorders suffered and recorded the major structural failure.

Image-Based Comprehensive Maintenance and Inspection Method for Bridges Using Deep Learning

2018 ◽  
Author(s):  
Xuefeng Zhao ◽  
Shengyuan Li ◽  
Hongguo Su ◽  
Lei Zhou ◽  
Kenneth J. Loh
Keyword(s):  
Neural Network ◽  
Deep Learning ◽  
Convolutional Neural Network ◽  
Visual Inspection ◽  
Health State ◽  
Bridge Management ◽  
Inspection Method ◽  
Maintenance Work ◽  
Maintenance And Inspection ◽  
Fine Turning

Bridge management and maintenance work is an important part for the assessment the health state of bridge. The conventional management and maintenance work mainly relied on experienced engineering staffs by visual inspection and filling in survey forms. However, the human-based visual inspection is a difficult and time-consuming task and its detection results significantly rely on subjective judgement of human inspectors. To address the drawbacks of human-based visual inspection method, this paper proposes an image-based comprehensive maintenance and inspection method for bridges using deep learning. To classify the types of bridges, a convolutional neural network (CNN) classifier established by fine-turning the AlexNet is trained, validated and tested using 3832 images with three types of bridges (arch, suspension and cable-stayed bridge). For the recognition of bridge components (tower and deck of bridges), a Faster Region-based Convolutional Neural Network (Faster R-CNN) based on modified ZF-net is trained, validated and tested by utilizing 600 bridge images. To implement the strategy of a sliding window technique for the crack detection, another CNN from fine-turning the GoogLeNet is trained, validated and tested by employing a databank with cropping 1455 raw concrete images into 60000 intact and cracked images. The performance of the trained CNNs and Faster R-CNN is tested on some new images which are not used for training and validation processes. The test results substantiate the proposed method can indeed recognize the types and components and detect cracks for a bridges.

Anomaly Criteria for General Visual Inspection of Subsea Flexible Pipes

2020 ◽  
Author(s):  
Damir Tadjiev
Keyword(s):  
Visual Inspection ◽  
Service Failure ◽  
Lessons Learned ◽  
Inspection Method ◽  
Deep Waters ◽  
Flexible Pipes ◽  
Increased Risk ◽  
Competent Person ◽  
Routine Basis ◽  
Areas Of Concern

Abstract For flexible pipes in subsea applications, General Visual Inspection (GVI) by Remotely Operated Vehicles (ROV) remains the most common inspection method that is used on a routine basis. It enables verification of pipe configuration or layout and also helps to identify any areas of concern indicative of an increased risk of in-service failure. The success of ROV GVI chiefly relies on the anomaly criteria used, these help inspectors to identify any areas of concern, which can then be assessed by a competent person to ensure any threat to the integrity of an inspected component is identified and addressed. Currently there are no commonly accepted anomaly criteria for ROV GVI of flexible pipes. As a result there is no consistent approach between different operators and experience shows that the inspection approach and anomaly criteria are often adopted from what has traditionally been used for rigid pipes. Since flexible pipes have different design and associated failure threats and mechanisms to rigid pipe, use of this approach may result in under or over inspection of flexible pipes. This paper presents a set of anomaly criteria for ROV GVI of flexible pipes. The criteria were developed using the experience and lessons learned from a population of approximately 350 flexible pipes from two different manufactures operating in deep waters of the UKCS for over a period of 20 years. The criteria cover dynamic flexible risers and associated ancillary equipment, seabed flexible flowlines and jumpers. The applicability of the proposed anomaly criteria to other systems, the benefits of having commonly accepted anomaly criteria, the anomaly detection capability of ROV GVI and the reporting of anomalies are also discussed.

scholarly journals Ambient Vibration Test on Reinforced Concrete Bridges

2016 ◽  
Vol 47 ◽  
pp. 02012 ◽  
Author(s):  
Nurul Shazwin Idris ◽  
Koh Heng Boon ◽  
Ahmad Fahmy Kamarudin ◽  
Sherliza Zaini Sooria
Keyword(s):  
Reinforced Concrete ◽  
Concrete Bridges ◽  
Ambient Vibration ◽  
Vibration Test ◽  
Ambient Vibration Test ◽  
Reinforced Concrete Bridges

scholarly journals A Review of Ambient Vibration Technique on Bridges

2015 ◽  
Vol 773-774 ◽  
pp. 1002-1006
Author(s):  
Nurul Shazwin Idris ◽  
H.B. Koh ◽  
Ahmad Fahmy Kamarudin
Keyword(s):  
Dynamic Characteristics ◽  
Ambient Vibration ◽  
Vibration Test ◽  
Dynamic Information ◽  
Ambient Vibration Test ◽  
Vibration Technique ◽  
Highly Sensitive ◽  
Sensitive Sensor ◽  
Non Destructive ◽  
Labour Time

Bridge is one of the important facilities use in daily life as bridge is built to span physical obstacles such as a body of water, valley or road for the purpose of providing passage over the obstacle. Various testing conducted on the bridge in order to know the dynamic characteristics of the bridges. One of popular testing use is ambient vibration test. Ambient vibration is a non-destructive test conducted using highly sensitive sensor. This testing is easy to be conduct with less labour, time and also cost. This paper aim to provide up to date literature review on ambient vibration test on bridge includes sources of ambient vibration, procedure of conducting the measurement and results from ambient vibration test. It is important to known the dynamic characteristics of the bridge especially to determine the dynamic response of the structure and also as dynamic information for seismic design.

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