Noncontact techniques for monitoring of tunnel linings

Abstract

An investigation of tunnel linings is performed at two tunnels in the US using complimentary noncontact techniques: air-coupled ground penetrating radar (GPR), and a vehicle-mounted scanning system (SPACETEC) that combines laser, visual, and infrared thermography scanning methods. This paper shows that a combination of such techniques can maximize inspection coverage in a comprehensive and efficient manner. Since ground-truth is typically not available in public tunnel field evaluations, the noncontact techniques used are compared with two reliable in-depth contact nondestructive testing methods: ground-coupled GPR and ultrasonic tomography. The noncontact techniques are used to identify and locate the reinforcement mesh, structural steel ribs, internal layer interfaces, shallow delamination, and tile debonding. It is shown that this combination of methods can be used synergistically to provide tunnel owners with a comprehensive and efficient approach for monitoring tunnel lining conditions.

Delamination and concrete quality assessment of concrete bridge decks using a fully autonomous RABIT platform

“…For example, in cases where deterioration is primarily caused by corrosion, the process can be described as the one initiated by the development of corrosive environment (Papadakis 2013). One of the ways to detect and characterize corrosive environment is by electrical resistivity (ER) measurements (Whiting and Nagi, 2003), and to some extent by ground penetrating radar (GPR) surveys (White 2014). As the corrosive environment becomes more severe, it will initiate corrosion activity in rebars.…”

Quantitative Attribute Analyses with Ground Penetrating Radar for Infrastructure Assessments and Structural Health Monitoring

“…In civil engineering, GPR is applied to map and locate utilities [7,8,9], monitor and inspect concrete structures for defects and anomalies in the service of civil infrastructure SHM and life-cycle management (e.g., [10]). Specifically, GPR has been used for damage identification in different ages and mixes of concrete [11], corrosion detection and prevention [12,13], robust estimates of pavement thickness [14,15,16] and identification of voids and other defects in civil structures [10,17]. Some work is being done on estimating and tracking the evolution of volumetric water content and dielectric properties, but mainly in the interest of understanding early age concrete hydration [18,19,20].…”

Predicting material properties of concrete from ground-penetrating radar attributes

“…[11][12][13][14] Specifically, GPR has been used for damage identification in different ages and mixes of concrete, 15 corrosion detection and prevention, 13,16 robust estimates of pavement thickness, [17][18][19] verification of construction specifications and details, 14,[20][21][22] and identification of voids and other defects in civil structures. 12,23…”

“…In civil engineering, GPR is applied to map and locate utilities 9–11 and monitor and inspect concrete structures for defects and anomalies in the service of civil infrastructure structural health monitoring (SHM) and life-cycle management. 11–14 Specifically, GPR has been used for damage identification in different ages and mixes of concrete, 15 corrosion detection and prevention, 13,16 robust estimates of pavement thickness, 17–19 verification of construction specifications and details, 14,20–22 and identification of voids and other defects in civil structures. 12,23…”