Modeling of environmental effects on thermal detection of subsurface damage for concrete bridges

Rumbayan, Rilya

doi:10.32469/10355/37808

Cited by 5 publications

(11 citation statements)

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“…Data were collected for six months and were analyzed to determine the environmental conditions that would make detection of subsurface delaminations more possible during practical bridge inspections. This research trend continued until 2013, with Rilya Rumbayan’s work [ 13 ]. Rumbayan developed a numerical model to predict thermal contrasts in subsurface delamination based on a given set of data from Washer’s [ 12 ] research.…”

Section: Related Workmentioning

confidence: 99%

Effects of Ambient Temperature and Relative Humidity on Subsurface Defect Detection in Concrete Structures by Active Thermal Imaging

Tran

Han

Kang

et al. 2017

Sensors

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Active thermal imaging is an effective nondestructive technique in the structural health monitoring field, especially for concrete structures not exposed directly to the sun. However, the impact of meteorological factors on the testing results is considerable and should be studied in detail. In this study, the impulse thermography technique with halogen lamps heat sources is used to detect defects in concrete structural components that are not exposed directly to sunlight and not significantly affected by the wind, such as interior bridge box-girders and buildings. To consider the effect of environment, ambient temperature and relative humidity, these factors are investigated in twelve cases of testing on a concrete slab in the laboratory, to minimize the influence of wind. The results showed that the absolute contrast between the defective and sound areas becomes more apparent with an increase of ambient temperature, and it increases at a faster rate with large and shallow delaminations than small and deep delaminations. In addition, the absolute contrast of delamination near the surface might be greater under a highly humid atmosphere. This study indicated that the results obtained from the active thermography technique will be more apparent if the inspection is conducted on a day with high ambient temperature and humidity.

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Section: Related Workmentioning

confidence: 99%

Effects of Ambient Temperature and Relative Humidity on Subsurface Defect Detection in Concrete Structures by Active Thermal Imaging

Tran

Han

Kang

et al. 2017

Sensors

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“…The time required for carbonation, or depassivation, can be estimated with the knowledge of the concrete permeability, k, and concrete cover, d, using the equation 2.3 [13]. It has been reported in the literature that carbonation rate is very slow and does not represent a serious threat for concrete structures [14].…”

Section: Corrosion Of Reinforcing Steelmentioning

confidence: 99%

“…The speed of conducting heat depends on the material's coefficient of thermal conductivity. The rate of the emitted energy is given by Stefan-Boltzmann law, equation 2.10 [14].…”

Section: Principlesmentioning

confidence: 99%

“…These are known as "passive" and "active" thermography. Heat in passive thermography can be applied naturally using solar heating provided by the sun in the daytime or ambient cooling during night times [14]. Alternatively, in active thermography experiments, heat can be applied artificially by using an external thermal stimulus, such as halogen lamps, ultrasound exciters, xenon flash lamps, or electrical heaters [34][35][36].…”

Section: Principlesmentioning

confidence: 99%

“…The limitations, on the other hand, is that IRT technology is dependent on weather condition during and prior to testing. Wind speed, presence of moisture (or ice in freezing weather conditions) on or below concrete surface, humidity, cloud cover, and precipitation can affect the amount of infrared radiation, and therefore, negatively influence IRT results [14,32]. The other limitation is that IRT can detect only shallow (up to 3-4 inches) subsurface anomalies from the surface being inspected.…”

Section: Advantages and Limitationsmentioning

confidence: 99%

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Advancements in evaluating reliability of nondestructive technologies for the detection of subsurface fracture damage in R.C. bridge decks

Sultan¹

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During the last few decades, many efforts have been made to assess the reliability of nondestructive evaluation (NDE) technologies used for the detection of subsurface damage in concrete bridge decks. During these efforts, reliability of NDE technologies has either been described anecdotally, or been solely relegated to the probability of detection (POD) or accuracy estimation. Although these indices are important, most of the previous work did not take into account the probability of false alarm (POFA) of NDE technologies, nor did they investigate the reliability considering multiple threshold settings throughout test results. In addition, the existing body of research has used a limited physical sampling such as coring to validate NDE results. Consequently, the assessments were rather controversial, and there was no general agreement about the reliability of such technologies. Because most diagnosis systems are characterized by noisy data and less than perfect detection characteristics, reliability is to be carefully assessed considering all possible diagnosis output with multiple threshold settings within practical range of applications. In other words, when NDE data do not fall into either of the two obviously defined categories: true positive (TP), meaning the NDE data indicates a defect and there is a defect, or true negative (TN), meaning the NDT data indicates no defect and there is no defect, reliability analysis should also include the two types of incorrect indications: failure to give a positive indication in the presence of a defect (false negative, FN) and giving a positive indication when there is no defect (a false alarm or false positive, FP). The \three decades of NDI reliability assessments" report developed by Karta Technologies, Inc. in 2000 under supervision of the Air Force NDI Office stated that POD alone cannot describe the reliability of NDE technologies unless the probability of false alarm (POFA) is also considered in the analysis. POFA may be induced by noise with several possible sources: human, nature of phenomenon to be measured, and environmental conditions. The report covered nearly 150 reports and manuscripts from over 100 authors. However, a review of research literature reveals that little theoretical work on the reliability assessment in terms of both POD and POFA has been undertaken since then. In this research, the reliability of impact echo (IE), infrared thermography (IRT), and ground penetration radar (GPR) technologies for the detecting of subsurface damage in concrete plate-like members is assessed by using a statistical analysis method called receiver operating characteristic (ROC). The proposed analysis method has the capability to integrate POD and POFA indices over a wide range of decision threshold settings in a single curve, which is useful in assessing trade-off in choosing a threshold and for quantitatively comparing the performance of NDE technologies. This methodology for assessing NDE reliability is intended to provide a more effective means of comparing different technologies used in civil engineering applications, to make the evaluation process of a quantitative scheme, to reduce subjectivity and variability in interpreting NDE data, and to improve sensitivity to extract more information from NDE data. Area under ROC curve (AUC), which is interpreted as the probability of correctly classifying an arbitrarily pair of negative and positive test points, can provide for the desired quantitative reliability index, which can be used to compare the performance of one NDE technology to another. Results of this research obtained from ROC analysis indicate a great ability of IE and IR in detecting subsurface fracture damage such as delamination and debonding. In both technologies, there exist some threshold settings that can provide for a relatively high POD with very low POFA, and consequently, the areas under their ROC curves were very high. Data obtained from GPR testing, on the other hand, indicates that GPR technology has a very limited ability to detect physical damage such as subsurface delamination. This conclusion contrasts with that been argued by a large body of the previous work. However, GPR showed a good sensitivity to the presence of corrosive environments such as moisture and chloride when the concentrations of these factors are above some threshold values that may facilitate the initiation of steel reinforcement corrosion.

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Infrared thermography detection of delamination in bottom of concrete bridge decks

Raja

Miramini

Duffield

et al. 2021

Structural Contr & Hlth

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Infrared thermography (IRT) has been widely used in detecting the subsurface delamination of bridge deck. However, IRT inspection on delamination zones of the bridge deck which have limited exposure to direct solar radiation (e.g., the bottom surface of the bridge deck) is rather challenging due to the relatively low thermal contrast (ΔT) development in these zones. Therefore, the purpose of this study is to conduct a series of experimental studies in conjunction with numerical modeling for investigating the effectiveness of IRT in delamination detection of bridge deck components which are normally not exposed to direct solar radiation. Specially, the effects of different environmental conditions, thickness of bridge deck, and defect characteristics on the absolute thermal contrast (ΔT) development were systematically investigated. The results show that IRT can effectively detect the subsurface delamination of concrete bridge deck located in regions that are not exposed to the direct solar radiation. In addition, the development of detectable thermal contrast (>0.5 C) is much dependent on the rate of change in ambient temperature with a suitable detection period between 8 am and 4 pm. Furthermore, it shows that the value of ΔT increases with the increase of bridge deck thickness and delamination size.

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Modeling of environmental effects on thermal detection of subsurface damage for concrete bridges

Cited by 5 publications

References 0 publications

Effects of Ambient Temperature and Relative Humidity on Subsurface Defect Detection in Concrete Structures by Active Thermal Imaging

Effects of Ambient Temperature and Relative Humidity on Subsurface Defect Detection in Concrete Structures by Active Thermal Imaging

Advancements in evaluating reliability of nondestructive technologies for the detection of subsurface fracture damage in R.C. bridge decks

Infrared thermography detection of delamination in bottom of concrete bridge decks

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