Health Monitoring of Rock Bolts Using Ultrasonic Guided Waves

He, Cunfu; Velsor, Jason K. Van; Lee, C. M.; Rose, Joseph L.

doi:10.1063/1.2184529

Cited by 16 publications

(13 citation statements)

References 6 publications

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“…Na et al [8,14,15] utilized the guided waves for the inspection of steel-concrete interfaces and glass fiber polymer-concrete interfaces. Ervin et al [16,17] used both low (<200 kHz) and high (2)(3)(4)(5)(6)(7)(8)(9) guided longitudinal modes to ultrasonically monitor the accelerated corrosion experiments. It was found that some modes were sensitive to the combined effect of bond deterioration and mortar stiffness reduction while some other modes related well to change in crosssectional area.…”

Section: Introductionmentioning

confidence: 99%

Longitudinal Guided Waves for Monitoring Chloride Corrosion in Reinforcing Bars in Concrete

Sharma

Mukherjee

2010

Structural Health Monitoring

102

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Corrosion of reinforcing steel in concrete is one of the major durability problems faced by civil engineers as they maintain an aging infrastructure. The problem accelerates since steel is embedded inside concrete. If it remains unnoticed inside concrete, it further accelerates and can cause loss of life and property. This article discusses a nonintrusive corrosion monitoring technique for early detection of damages in steel embedded in concrete. Corrosion manifests itself in debond and pitting steel bars. Guided ultrasonic waves offer a potentially attractive solution for this problem. But it is imperative to excite the right mode for detection of a particular type of corrosion. In the present work, longitudinal guided ultrasonic waves have been utilized to monitor notch and debond defects in steel bars in concrete simulating pitting and delamination phenomena caused by corrosion. Two ultrasonic techniques of pulse transmission and pulse echo were used to monitor the healthy and damaged specimens. The developed methodology is successfully applied for real time monitoring of RC beam specimens undergoing accelerated chloride corrosion. The ultrasonic signals effectively relate to the state of reinforcing bars.

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Section: Introductionmentioning

confidence: 99%

Longitudinal Guided Waves for Monitoring Chloride Corrosion in Reinforcing Bars in Concrete

Sharma

Mukherjee

2010

Structural Health Monitoring

102

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“…If these cracks are closed and hence poor reflectors, then nonlinear methods must be incorporated under the constraints imposed by guided-wave propagation in the element (Pruell 2009;Jhang 2000). A number of investigators have covered rod-guided waves with the intent of solving problems such as rebar corrosion in concrete, rock anchor-bolt bonding, and utility pole, guidewire anchor corrosion in soils (Beard 2003;Erwin et al 2009;Yang and Yu 2006;He et al 2006 ). In general, these three specific applications need high sensitivity at the rod surface and therefore benefit from narrow-band, guided-wave modes such as low-order longitudinal or torsional modes that result in relatively higher levels of acoustical energy at or near the rod's surface.…”

Section: Approachmentioning

confidence: 99%

Development of a Guided-Wave Technology Capable of the Detection of Open Cracks and Microcracks in Embedded Trunnion Anchor Rods

Evans¹,

Haskins²

2014

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BACKGROUND: Catastrophic failure of post-tension trunnion anchor rods at dams is an ongoing problem caused by propagating orthogonal stress corrosion cracks described in CHETN-IX-32 (Evans et al. 2013). This condition is shown in Figure 1 which presents a cracked rod that was removed from Robert F. Henry Lock and Dam, which has 376 trunnion rods supporting the tainter gates. In the broken rod image, a blue arrow indicates the fracture origin, and white arrows indicate the crack propagating direction. The green ellipse encircles an area that contains a pre-existing crack. This older crack area is more heavily oxidized than the rest of the fracture surface. This crack over time resulted in the complete failure of the rod. The right side of Figure 1 shows the tainter gate trunnion rods located on a dam pier. These rods serve to prestress the concrete to prevent excessive tensile loading on the concrete during gate operation.

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“…They also selected a high surface interface sensitive mode such as the L(0,1)'s low attenuation point around 100 kHz to detect progressive debonding between grout and steel due to corrosion. He et al (2006) performed similar guided wave measurements for rock-bolt debonding localization and characterization at distances up to 10 ft.…”

Section: Defect Detectionmentioning

confidence: 99%

Assessing Corrosion Damage and Corrosion Progression in Multistrand Anchor Systems in Use at Corps Projects

Ebeling¹,

Strom²,

Hite³

et al. 2013

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Stressed steel tendons have been used to strengthen hydraulic structures and to improve their serviceability and stability. Over the past three decades, the US Army Corps of Engineers has worked to upgrade its projects by installing high-capacity, post-tensioned foundation anchors. The goal has been to achieve structural stability for Corps hydraulic concrete structures and/or to remediate cracked concrete monoliths. Substantial improvements to protect multistrand anchor systems from corrosion have been made since they were first used at Corps projects more the 50 years ago. Corrosion of older multistrand units is of concern.Researchers at the US Army Engineer Research and Development Center (ERDC) are looking to develop engineering procedures to estimate the current state of load-carrying capacity of the ground anchorage, to estimate remaining life of the tendon, and to establish the deterioration of anchorage capacity (with time) so costly replacement of ground anchorage can be delayed until absolutely needed. Analytical, laboratory, and field-testing efforts will be used to develop a methodology and analytical models. Probabilistic procedures will be used to quantify uncertainties for the primary variables and will be carried into the analytical model. Procedures to extend the life of deteriorating multistrand tendons also will be investigated.A review of Corps projects using multistrand anchors and a literature review of corrosion of the anchors are summarized in this report. Also included are the history and performance of the multistrand anchors at the John Day Navigation Lock (Columbia River, Portland District), along with postinstallation lift-off test results. A summary of a review of nondestructive testing (NDT) to identify defects in the anchors is part of this report, too.

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Health Monitoring of Rock Bolts Using Ultrasonic Guided Waves

Cited by 16 publications

References 6 publications

Longitudinal Guided Waves for Monitoring Chloride Corrosion in Reinforcing Bars in Concrete

Longitudinal Guided Waves for Monitoring Chloride Corrosion in Reinforcing Bars in Concrete

Development of a Guided-Wave Technology Capable of the Detection of Open Cracks and Microcracks in Embedded Trunnion Anchor Rods

Assessing Corrosion Damage and Corrosion Progression in Multistrand Anchor Systems in Use at Corps Projects

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