Prediction of load transfer depth for cost-effective design of ground anchors using FBG sensors embedded tendon and numerical analysis

Manh, Tan; Kim, Young Sang

doi:10.12989/gae.2016.10.6.737

Cited by 8 publications

(7 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Building upon FBG sensors, De Waele et al [ 22 ] developed a load cell to measure the forces in the ground anchors of a quay wall, and concluded that fiber-based instrumentation is highly suitable for long-term monitoring purposes. Kim et al [ 23 ] and Do et al [ 24 ] encapsulated FBG sensors into the central king cable of a 7-wire steel strand to monitor the changes in tensile force and its distribution along the tendons during in-service state. They stated the sensors were embedded into the steel tube by a liquid glue with low viscosity.…”

Section: Introductionmentioning

confidence: 99%

Study on the Optimal Groove Shape and Glue Material for Fiber Bragg Grating Measuring Bolts

Zhao

Zhang

et al. 2018

Sensors

View full text Add to dashboard Cite

Fiber Bragg grating (FBG) measuring bolts, as a useful tool to evaluate the behaviors of steel bolts in underground engineering, can be manufactured by gluing the FBG sensors inside the grooves, which are usually symmetrical cuts along the steel bolt rod. The selection of the cut shape and the glue types could perceivably affect the final supporting strength of the bolts. Unfortunately, the impact of cut shape and glue type on bolting strength is not yet clear. In this study, based on direct tension tests, full tensile load–displacement curves of rock bolts with different groove shapes were obtained and analyzed. The effects of groove shape on the bolt strength were discussed, and the stress redistribution in the cross-section of a rock bolt with different grooves was simulated using ANSYS. The results indicated that the trapezoidal groove is best for manufacturing the FBG bolt due to its low reduction of supporting strength. Four types of glues commonly used for the FBG sensors were assessed by conducting tensile tests on the mechanical testing and simulation system and the static and dynamic optical interrogators system. Using linear regression analysis, the relationship between the reflected wavelength of FBG sensors and tensile load was obtained. Practical recommendations for glue selection in engineering practice are also provided.

show abstract

Section: Introductionmentioning

confidence: 99%

Study on the Optimal Groove Shape and Glue Material for Fiber Bragg Grating Measuring Bolts

Zhao

Zhang

et al. 2018

Sensors

View full text Add to dashboard Cite

show abstract

“…Bragg grates are implemented together with anchor rods that are used to strengthen rock bodies. This approach serves to monitor the stress-deformation state in the anchors to warn against rock movements and their disturbances [5]. Further, FBGs are used to measure deformations in the secondary lining of tunnels [6], where quasi-distributed measurements can be used by multiplex techniques [7Systems based on Brillouin scattering are advantageous in terms of distributed distribution of deformations along the entire optical fibre.…”

Section: Introductionmentioning

confidence: 99%

Distributed fibre-optic technology for security monitoring of a structural load of road and motorway tunnels

Hruby¹,

Kepák²,

Mec³

et al. 2019

International Conference on Civil, Structural and Transportation Engineering

View full text Add to dashboard Cite

The article is focused on the analysis of the use of the distributed fiber optic technology for security monitoring of a structural load of road and motorway tunnels. Brillouin Time Domain Reflectometry (BOTDR) was used to monitor the deformation. The principle is based on the measurement of the stimulated Brillouin scattering. The whole experiment was carried out during the construction of the motorway tunnel in Slovakia. As part of the construction of the tunnel, the standard optical telecommunication fiber was attached to the primary tunnel beams that was subsequently used as a sensor for the BOTDR system. The sensor allows monitoring and analysis of the load on the highway tunnel to ensure the safety of the structural load. In total, there were 6 measurement days, which were scheduled in 5 months of tunnel construction.

show abstract

“…The tensile evaluations showed that the embedded FBG sensors were capable of withstanding a high strain of 1.5%. FBG sensors are also applied to monitor the axial stress of rock bolts throughout the process of constructing underground tunnels by utilizing pilot models and investigating the load transfer principle of the ground anchor and tensile force distribution along the tendon [11,12]. Iten and Puzrin [13] utilized the Brillouin optical time domain analysis (BOTDA) optical fiber-distributed sensing tactic for measuring the stress distribution along ground anchors.…”

Section: Introductionmentioning

confidence: 99%

Assessing the Difference in Measuring Bolt Stress: A Comparison of Two Optical Fiber Sensing Techniques

Chai

Liu

et al. 2018

Journal of Sensors

View full text Add to dashboard Cite

Monitoring the load level of the rock bolts is of great importance for assessing risk. Based on the mechanical transmission mechanism of grouting bolts, the bolt pull-out test was carried out in lab. The performance of the bolt under pull-out loading was measured using the pulse-pre-pump Brillouin optical time domain analysis (PPP-BOTDA) and fiber Bragg grating (FBG) sensing technologies. The distribution characteristic of axial stress along the bolt was analysed in combination with the measurements obtained by the two sensing technologies. The relative standard deviation for repeatability errors in the determination and the setting time of resin grout was investigated. The results show that the distribution of axial stress is nonuniform along the anchorage section. The maximum value of axial stress on the bolt is closed to the pull-out side. The relative standard deviation for repeatability errors obtained by PPP-BOTDA is less than that obtained by FBG. The comparison of the measurements obtained by the two methods indicates that when the drawing force is greater than 20 kN and the axial stress is more than 10 kN, the two methods have better consistency. In the field application, it is necessary to estimate the deformation of matrix, leaving at least 500 minutes for resin bond to work.

show abstract

Prediction of load transfer depth for cost-effective design of ground anchors using FBG sensors embedded tendon and numerical analysis

Cited by 8 publications

References 14 publications

Study on the Optimal Groove Shape and Glue Material for Fiber Bragg Grating Measuring Bolts

Study on the Optimal Groove Shape and Glue Material for Fiber Bragg Grating Measuring Bolts

Distributed fibre-optic technology for security monitoring of a structural load of road and motorway tunnels

Assessing the Difference in Measuring Bolt Stress: A Comparison of Two Optical Fiber Sensing Techniques

Contact Info

Product

Resources

About