Crack detection limits in unit based masonry with terrestrial laser scanning

Laefer, Debra F.; Truong-Hong, Linh; Carr, Hamish; Singh, Manmeet

doi:10.1016/j.ndteint.2013.11.001

Cited by 103 publications

(61 citation statements)

References 23 publications

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“…As an example, according to a recent study by Laefer et al [11], TLS can detect a crack as little as twice its sampling step (confirming the values of 1.6mm to 4.8mm proposed by Ahlborn et al [1]). Based on this, a TLS-based crack detection workflow is proposed in (Figure 4).…”

Section: Discussionsupporting

confidence: 76%

Application of Terrestrial Laser Scanner In Bridge Inspection: Review and an Opportunity

Truong-Hong¹,

Laefer²

2014

IABSE Reports

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Abstract:Heavy traffic and aggressive environmental conditions can cause unexpected bridge deterioration. Traditional condition evaluation is expensive. An alternative is Terrestrial laser scanning (TLS) which is a non-contact approach that safe, fast, and applicable to a range of weather conditions. This paper reviews applications of TLS on bridge measurement involving geometric documentation, surface defect determination, and corrosion evaluation, and crack identification. Currently, most post-processing of TLS is manual or within third party software. This paper discusses potential approaches to automatic post-processing.

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Section: Discussionsupporting

confidence: 76%

Application of Terrestrial Laser Scanner In Bridge Inspection: Review and an Opportunity

Truong-Hong¹,

Laefer²

2014

IABSE Reports

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“…Several image processing studies have been done in order to detect defects automatically [4,5,6,7,8]. However, the images are affected by the light conditions and their analysis requires supplementary information [9]. On the other hand, LiDAR is used for collecting point clouds.…”

Section: Methods For Surface Defects Inspectionmentioning

confidence: 99%

High Level Framework for Bridge Inspection Using LiDAR-Equipped UAV

Bolourian¹,

Soltani²,

Hammad³

et al. 2017

Proceedings of the International Symposium on Automation and Robotics in Construction (IAARC)

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-According to Statistics Canada, bridges in Canada have a service life of approximately 43 years. With the majority of bridges passing half of their expected service life, a large amount of investment needs to be made to inspect and maintain them in a safe condition. Manual inspection methods are both time-consuming and costly, which may discourage further inspections and follow-up of defects. Thus, there is a great need for using an automated data collection system. Surface defects (e.g. cracks) in concrete bridges can be inspected using 3D Light Detection and Ranging (LiDAR) scanner as a Non-Destructive Testing (NDT) method. However, the commonly used terrestrial LiDAR is limited to stationary data collection, which reduces the accessibility to some components of the bridges. To tackle this limitation, a LiDAR attached to an Unmanned Aerial Vehicle (UAV) provides more flexibility and accessibility for inspecting large surface areas without threatening inspectors' safety. After providing a comprehensive literature review about the usage of UAVs and LiDAR for the inspection of different types of structures, this paper proposes a high level framework for bridge inspection using LiDAR-equipped UAV. The framework includes the following steps: (1) planning a collisionfree optimized path with respect to the minimum cost and maximum coverage considering a variety of constrains and requirements related to the hardware and the inspection task, and (2) data analysis for detecting the surface defects based on the collected point clouds.

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“…5b). Next, an outlier remove procedure (step 2.1) was proposed to iteratively eliminate outlier points -those having a distance from the point to the fitting surface of the connection plate that is larger than the perpendicular noise level of the range measurement [13,14]. The process was considered complete when no outlier point remained or the deviation between the normal vectors of two consecutive fitting planes was less than 1 degree.…”

Section: Connectionmentioning

confidence: 99%

A Semi-Automatic Member Detection for Metal Bridges

Truong-Hong

Laefer²

2015

IABSE Reports

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Abstract:Terrestrial laser scanners (TLSs) are prominent non-contact instruments for acquiring highly detailed geometries of bridge components in only minutes. A TLS can be a strategic instrument for data collection for bridge inspection and documentation, because it can reduce significantly required field time and auxiliary equipment. To deploy a TLS in this field, a semi-automatic method for post-processing a point cloud for documentation of a historic metal bridge is proposed. In this work, generating 3D model of existing structural members and identifying connection characteristics are mainly of interest. The Guinness Bridge built in 1880s in Dublin, Ireland is presented as a case study for the proposed semi-automatic workflow.

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Crack detection limits in unit based masonry with terrestrial laser scanning

Cited by 103 publications

References 23 publications

Application of Terrestrial Laser Scanner In Bridge Inspection: Review and an Opportunity

Application of Terrestrial Laser Scanner In Bridge Inspection: Review and an Opportunity

High Level Framework for Bridge Inspection Using LiDAR-Equipped UAV

A Semi-Automatic Member Detection for Metal Bridges

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