Portable linear accelerators for X-ray and electron-beam applications in civil engineering

Owen, Roger DeBaun

doi:10.1016/s0963-8695(98)00042-5

Cited by 13 publications

(7 citation statements)

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“…The results presented here add versatility and reduce the cost of the inspections done with other methodologies, such as the ultrasonic pulse velocity [6,31] and the high energy radiography. [7,8] Due to the cost and complexity of those techniques, the most common procedure nowadays is the visual inspection, which cannot give accurate predictions of the structural integrity. Our results prove also that the visual inspection based on the orientation and number of cracks can lead to a misleading interpretation.…”

Section: Discussionmentioning

confidence: 99%

Contactless safety evaluation of damaged structures through energetic criteria

Saucedo-Mora

Perdrix

Hombrados

et al. 2017

Struct Control Health Monit

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SummaryThe reinforced concrete structures need to be monitored to ensure their structural integrity, but sometimes those measurements are very local, and the instrument is complex to locate physically in the structure and may interfere on it. Digital Image Correlation is a noncontact and nondestructive experimental technique capable to measure the displacement field in a big region of a structure with a great accuracy.This allows extracting valuable information from the fracture processes of reinforced concrete structures, critical for the evaluation of the structural integrity. The measurement of the energy dissipated by the structure is essential for the identification of the strength mechanisms that are failing in the structure and to identify a proper repair. Also, using fracture mechanics, other valuable information are extracted from the fracture processes of the reinforced concrete beam, such as the Modes I and II fracture energy released at each loading step, which is essential to evaluate the elastic energy that the structure can accumulate before collapse. The examples enable to anticipate the importance of Digital Image Correlation for future large scale studies of fracture in concrete and other materials related to construction.

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Section: Discussionmentioning

confidence: 99%

Contactless safety evaluation of damaged structures through energetic criteria

Saucedo-Mora

Perdrix

Hombrados

et al. 2017

Struct Control Health Monit

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“…However low-density materials make the film background black. For instance, Weng (1984), Owen, (1998, and Dixon and Dugdale (1988) have noted that when the radiation energy is 0.5 -10 MeV, the concrete absorption is µ . =.…”

Section: Radiation-generated Imagerymentioning

confidence: 99%

“…Griffiths and Barker (1993) and Weil (1996) have utilized ground penetration radar to analyze the status of holes within steels. Owen, (1998) has utilized a high-energy linear accelerator to generate high energy X-rays (1.5-6 MeV). This method generates images of the structure of RC and steels.…”

Section: Introductionmentioning

confidence: 99%

Radioactive methods for detecting concrete imperfections and steel locations

Chen

Peng

Jan

et al. 2008

Journal of the Chinese Institute of Engineers

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Non-destructive testing (NDT) is used extensively in structural forensic engineering to evaluate the quality of reinforced concrete. Identifying imperfections or the location of steel in highly non-uniform concrete is rather difficult simply because the examination results cannot achieve the desired precision. NDT remains inadequate in numerous situations where the quality of concrete needs to be assessed. This study proposes using penetrative radiation to capture the characteristics of concrete on film. Computers can then be utilized as a post-processing tool to eliminate image distortion. The magnification (decrease) scales can be determined using image positioning software. The geometric projection principle can then be applied directly to calculate the relative size and position, or void position, of the steel bars. Under laboratory conditions the size and position of the steel in 15-cm thick concrete can be determined using this method. Most importantly, this method can be achieved via an imaging medium, thereby increasing the practical value of radiation wave inspections in forensic engineering.

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“…Current nondestructive testing (NDT) approaches developed for civil engineering application include the use of ultrasound, X-ray and neutron radiography, near-field and far-field radar, and infrared thermography. 7–19 However, these techniques may not always be optimal for the remote detection of interfacial defects. 1 Passive thermography typically has insufficient spatial resolution to resolve small interfacial defects.…”

Section: Introductionmentioning

confidence: 99%

“…18 Radiography involves the use of hazardous ionizing radiation. 10,11 The radar approach may have issues if carbon fiber–reinforced polymer (CFRP) sheets being penetrated by radar are not arranged in a parallel orientation as CFRP is a highly conductive material at microwave frequencies. 14 Finally, while near-field radar and ultrasound are promising approaches, they require a close proximity to the subject.…”

Section: Introductionmentioning

confidence: 99%

A photophone-based remote nondestructive testing approach to interfacial defect detection in fiber-reinforced polymer-bonded systems

Cheng

Lau

2017

Structural Health Monitoring

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Externally bonded fiber-reinforced polymer is an increasingly popular material to be used in strengthening and retrofitting aging structures. In such structures, debonding defects may occur at or near the interface between fiber-reinforced polymer and concrete. As such debonding in fiber-reinforced polymer-bonded systems is generally brittle in nature, there is a need of a reliable inspection technique that can provide early warning of interfacial defects such that premature failure of fiber-reinforced polymer-strengthened structures can be avoided. A remote nondestructive testing approach based on the working principle of a photophone is presented here as an economical alternative to laser Doppler vibrometry for detecting interfacial defects. Concrete specimens retrofitted with fiber-reinforced polymer are excited acoustically by white noise, while the surface of the structure is illuminated by a light source. If an interfacial defect exists beneath the surface, the surface will exhibit a frequency response different from an intact surface. The surface of the fiber-reinforced polymer portrays the role of flexible mirror in a photophone, which encodes information about surface vibration into amplitude-modulated light signal. A light detector then captures the irradiance of the reflected beam, and the amplitude modulation is converted into frequency domain in post-processing. With this technique, defect dimensions and thus damage extent can be inferred from the frequency spectrum obtained. The obtained results correspond well with the theoretical calculation, demonstrating the robustness and the applicability of the proposed technique in civil infrastructure.

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Portable linear accelerators for X-ray and electron-beam applications in civil engineering

Cited by 13 publications

References 0 publications

Contactless safety evaluation of damaged structures through energetic criteria

Contactless safety evaluation of damaged structures through energetic criteria

Radioactive methods for detecting concrete imperfections and steel locations

A photophone-based remote nondestructive testing approach to interfacial defect detection in fiber-reinforced polymer-bonded systems

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