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Journal ArticleDOI

Digital Image Correlation Technique for Measurement of Surface Strains in Reinforced Asphalt Concrete Beams under Fatigue Loading

TL;DR: Geosynthetic products are routinely used to reinforce pavement overlays to control crack propagation under repeated vehicular and varying thermal loads as mentioned in this paper, and many experimental methods are availa...
Abstract: Geosynthetic products are routinely used to reinforce pavement overlays to control crack propagation under repeated vehicular and varying thermal loads. Many experimental methods are availa...
Citations
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Journal ArticleDOI
TL;DR: Semi-flexible pavement (SFP) as discussed by the authors is a new pavement technology consisting of open-graded asphalt concrete with a high air void content filled by injecting special grouting materials.

55 citations

Journal ArticleDOI
TL;DR: The state-of-the-art in Image-based analysis techniques and their applications in construction is explored, including integrating object detection with quantification and sizing techniques to develop more comprehensive applications.

50 citations

Journal ArticleDOI
TL;DR: In this article, a digital image correlation (DIC) has been evaluated for its applicability on coal specimen and the average threshold stress levels of crack initiation and crack damage in uniaxial compression were observed to be 43.72% and 63.6% respectively.
Abstract: Efficient execution of the underground coal extraction depends on the accuracy of deformation measurement of the pillars. The basic design information as stress-strain behavior is collected from the laboratory investigation. Contact-based deformation measurement approaches have limitations like data insufficiency, proneness to signal loss, physical damage, etc. In this investigation, a contactless technique like digital image correlation (DIC) has been evaluated for its applicability on coal specimen. Coal specimens from 100-m depth have been investigated for their stress-strain behavior through DIC as well as other conventional methods, i.e., strain gauge and linear variable differential transformer (LVDT). The deformation was found out from a set of images recorded and analyzed using the software StrainMaster. In the image analysis, the optimum subset size was found to be 99 × 99 pixels with a step size of 8 pixels. The average threshold stress levels of crack initiation and crack damage in uniaxial compression were observed to be 43.72% and 63.6%, respectively. DIC exhibits higher sensitivity to deformation of coal as compared to that by LVDT and strain gauges and proven to be a promising and dependable technique for coal pillar analysis.

7 citations

Journal ArticleDOI
TL;DR: In this article , a non-contact UAV image correlation (UAVIC) technique is used on a scaled bridge girder and a contact method of measuring deformations with a dial gauge.
Abstract: Reinforced cement concrete (RCC) is universally acknowledged as a low-cost, rigid, and high-strength construction material. Major structures like buildings, bridges, dams, etc., are made of RCC and subjected to repetitive loading during their service life for which structural performance deteriorates with time. Bridges and high-rise structures, being above ground level, are hard to equip with the contact mechanical methods to inspect strains and displacements for structural health monitoring (SHM). A non-contact, optical and computer vision based full field measuring technique called digital image correlation (DIC) technique was developed in the recent past to specifically evaluate bridge decks. Generally, optical images of structure in field conditions are not acquired precisely perpendicular to the object, which instinctively affects the deformation results obtained during loading conditions. An unmanned aerial vehicle (UAV) equipped with DIC vision-based technique acts as a rapid and cost-effective tool to quantify the serviceability of bridges by measuring strains and displacements at inaccessible locations. In this study, a non-contact unmanned aerial vehicle image correlation (UAVIC) technique is used on a scaled bridge girder and a contact method of measuring deformations with a dial gauge. Both investigations are correlated for accuracy assessment, and it is understood that results in laboratory conditions are 90% accurate. Similarly, the UAVIC technique is also performed on a rail over the bridge in the field conditions to understand the feasibility of the proposed method and evaluate damage quantification of it.

5 citations

References
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Journal ArticleDOI
TL;DR: An improved digital correlation method is presented for obtaining the full-field in-plane deformations of an object by numerically correlating a selected subset from the digitized intensity pattern of the undeformed object.

1,788 citations

Journal ArticleDOI
TL;DR: In this paper, the surface displacement components in laser speckle metrology were measured using a digital image scanner interfaced to a computer. Butt et al. used a boundary integral equation method to calculate surface traction in the contour.
Abstract: Digital imaging techniques are utilized as a measure of surface displacement components in laser speckle metrology. An image scanner which is interfaced to a computer records and stores in memory the laser speckle patterns of an object in a reference and deformed configuration. Subsets of the deformed images are numerically correlated with the references as a measure of surface displacements. Discrete values are determined around a closed contour for plane problems which then become input into a boundary integral equation method in order to calculate surface traction in the contour. Stresses are then calculated within this boundary. The solution procedure is illustrated by a numerical example of a case of uniform tension.

1,617 citations

Journal ArticleDOI
TL;DR: A deformation measurement system based on particle image velocimetry (PIV) and close-range photogrammetry has been developed for use in geotechnical testing as mentioned in this paper.
Abstract: A deformation measurement system based on particle image velocimetry (PIV) and close-range photogrammetry has been developed for use in geotechnical testing. In this paper, the theory underlying this system is described, and the performance is validated. Digital photography is used to capture images of planar soil deformation. Using PIV, the movement of a fine mesh of soil patches is measured to a high precision. Since PIV operates on the image texture, intrusive target markers need not be installed in the observed soil. The resulting displacement vectors are converted from image space to object space using a photogrammetric transformation. A series of validation experiments are reported. These demonstrate that the precision, accuracy and resolution of the system are an order of magnitude higher than previous image-based deformation methods, and are comparable to local instrumentation used in element testing. This performance is achieved concurrent with an order of magnitude increase in the number of meas...

1,180 citations

Journal ArticleDOI
TL;DR: The updated approach combines a range of advances in image analysis algorithms and techniques best suited to geotechnical applications and achieves an improvement by at least a factor of 10 in measurement precision relative to the most commonly used particle image velocimetry (PIV) approach.
Abstract: This paper describes and benchmarks a new implementation of image-based deformation measurement for geotechnical applications. The updated approach combines a range of advances in image analysis al...

274 citations

Journal ArticleDOI
TL;DR: The underlying mechanisms governing the behavior of displacement piles in sand are not well understood, leading to unreliability in design methods as discussed by the authors, and a series of plane-strain calibration chamber tes...
Abstract: The underlying mechanisms governing the behaviour of displacement piles in sand are not well understood, leading to unreliability in design methods. A series of plane-strain calibration chamber tes...

261 citations