Hybrid Cross-Laminated Timber under Bending: Finite Element Analysis Based on Nondestructive Testing

Corrosion engineers take Nondestructive Testing (NDT) measurements at height as a method of determining the condition of Oil & Gas and other assets such as flare stacks, boilers, above ground storage and pressure vessels, piping and more. To do this at elevation currently the engineer may need to utilize a lift, scaffolding, ladders, or ropework or even inspection trucks with elevated baskets, sometimes cranes or even specialty access such as rigging catwalks, or other solutions. The engineer will often hold a handheld digital testing device to the asset to take the measurements in these scenarios. While NDT inspection programs can dramatically increase the safety and integrity of infrastructure, industrial and manufacturing assets, access requirements in performing these inspections at elevation introduces risk. NDT inspection sites often require access to elevated areas and require the use of personal fall protection equipment (safety harness and lanyard). Working at height is dangerous, due to the possibility of falls, as well as being time-consuming due to access. In certain instances, it may also require taking an asset, such as a flare stack or chimney stack, offline to allow it to cool so it can be accessed to take NDT readings. Utilizing an aerial robotics platform that makes contact with a surface in order to gather NDT measurements such as Dry Film Thickness (DFT), Surface Profile (SP), or Ultrasonic Thickness (UT) allows workers to remain safely on the ground. Since there is no need to move a lift, scaffolding or ladders and minimal movements required by the corrosion engineer or the robotic operator, the NDT measurement process can be faster in addition to being safer. Further, since the aerial robotic system (drone) contains onboard computers and sensors it is able to capture a lot of data during the exercise of an NDT inspection regime. Use of these aerial robotic NDT systems in offshore and marine environments carries unique challenges and operational variables. The Aerial Robotic System described in this paper afford safer, cheaper, and better NDT measurements and allow a more robust viewpoint into assets conditions than the slower and more expensive manual method. While early adopters in the offshore Oil & Gas and maritime industry stand to gain the most from implementing these systems they are also assuming the most risk until the systems become an industrial standard.

The use of aerial robotic systems that physically contact oil and gas structural assets to obtain measurement data in offshore and marine environments carries unique challenges and operational variables. The objectives of this paper are to demonstrate, with examples, how these aerial robotic systems afford safer, cheaper, and better nondestructive testing (NDT) measurement collection methodology and allow more robust insight into assets conditions than the slower, less safe, and more expensive manual method. To take NDT measurements such as Ultrasonic Wall Thickness (UT) Measurements at height, currently one needs to utilize a lift, ladders or other solutions to reach areas on certain assets. This can be both dangerous, due to the possibility of falls, and time consuming. Utilizing an aerial robotics platform for contact based (not visual) NDT measurements such as Ultrasonic Thickness (UT) allows workers to remain safely on the ground. Drones, with robotic arms, have the potential to improve inspection, testing and data collection. This paper explores an aerial robotic system that flies up to a structure with a metal sub-straight, then under full autonomous software control, touches a UT measurement probe to the target and records the measurement data compliant with American Petrolium Institute (API) and other standards. The use of aerial robotics systems for NDT is still a new and novel application utilizing existing technologies such as electronic measurement readers, drones, etc. with a system of complex integrations that allows for a better application of science. Aerial Robotic NDT systems have the potential to improve the inspection, testing and data collection aspects of coated and uncoated assets, in part, by making the NDT measurement process easier and safer thus allowing for more frequent measurements and/or a larger quantity of measurement samples. When possible, working at heights should be eliminated as part the hierarchy of fall protection stipulated by both OSHA and ANSI. For this reason alone, the use of aerial robotic systems is important now and in the immediate future Oil & Gas infrastructure, including Offshore. This paper intends to provide readers an awareness of this new technology as well as provide information about its efficacy, limitations and operational requirements.

For corrosion engineers to take Nondestructive Testing (NDT) measurements at height, currently they may need to utilize a lift, scaffolding, ladders, inspection trucks with elevated baskets, rope work, catwalks, cranes and rigging or other solutions. NDT inspection programs can dramatically increase the safety and integrity of infrastructure, industrial and manufacturing assets, access requirements in performing these inspections introduces risk. NDT inspection sites often require access to elevated areas and the use of equipment such as personal fall protection (safety harness and lanyard). Working at height is dangerous, due to the possibility of falls, as well as being time-consuming due to access. In certain instances, it may also require taking an asset, such as a flare stack, offline to allow it to cool so it can be accessed to take NDT readings. Use of handheld digital testing devices is very common in these scenarios. Utilizing an aerial robotics platform for contact-based NDT measurements such as Dry Film Thickness (DFT), Surface Profile (SP), or Ultrasonic Thickness (UT) allows workers to remain safely on the ground. Further, since there is no need to move a lift, scaffolding or ladders and minimal movements required by the corrosion engineer or the robotic operator, the NDT measurement process can be faster in addition to being safer.

Shear properties of hybrid CLT fabricated with lumber and OSB

The compressive strength of concrete is one of the most important mechanical parameters in the evaluation of the mechanical performance of reinforced concrete structures. The recent methodology for the evaluation of the mechanical strength of concrete of an existing structure combines non-destructive testing (NDT) measurements, such as rebound measurement and ultrasonic wave propagation velocity measurement, with destructive measurements (sampling) in order to develop a conversion model, between mechanical strength and non-destructive measurements. The conversion model is then used to estimate the local value of the resistance at each location of the non-destructive measurements and thus to represent the spatial variability. The goal of this study is to propose a new methodology based on multi-objective optimization to predict the compressive strength of concrete and its variability based on NDT measurements. To this end, a large experimental and synthetic database of destructive and non-destructive tests was used. The conclusions drawn from the synthetic data will be compared with the results obtained on the real database in order to test the potential of the proposed methodology. This study shows the principle of the methodology and the first results of its effectiveness in predicting compressive strength and its variability.

Non-destructive testing (NDT) methods are widely used to evaluate the performance of concrete, but their accuracy can be influenced by external factors such as curing temperature. Temperature not only modifies hydration kinetics and strength development but may also change the correlation between NDT measurements and compressive strength. However, no prior research has systematically examined how different curing temperatures influence the reliability of various NDT techniques. This study evaluates three curing temperatures and their effect on the correlation between NDTs and compressive strength at various ages (1, 3, 7, 28, and 90 days). Both simple regression analysis and artificial neural networks (ANNs) were employed to predict strength from NDT measurements. Results show that NDT sensitivity to curing temperature is most pronounced at early ages, and that linear regression models cannot adequately capture the complexity of these relationships. In contrast, ANNs demonstrated superior predictive capability, though initial training with limited data led to overfitting and instability. By applying Gaussian Noise Augmentation (GNA), model accuracy and generalization improved substantially, achieving R2 values above 0.95 across training, validation, and test sets. These findings highlight the potential of non-linear models, supported by data augmentation, to improve prediction reliability, lower experimental costs, and more accurately capture the role of curing temperature in NDT–strength correlations for concrete.

Characterization of random fields from NDT measurements: A two stages procedure

Non-Destructive Testing (NDT) techniques are affected by concrete properties such as porosity, water content, strength, etc. Extracting one concrete property from one NDT measurement may lead to considerable uncertainties. This highlights the benefit of NDT data fusion to evaluate accurately concrete properties. In this paper, NDT measurements from several NDT techniques were combined to predict more accurately concrete properties such as porosity and water saturation. Two techniques of data fusion were used namely neuro-fuzzy network and theory of possibility. The results obtained show the effectiveness of the statistical modelling to predict the properties of concretes by fusion of NDT measurements.

Concrete properties evaluation by statistical fusion of NDT techniques

Strand-based engineered wood products (EWPs) have been widely employed in construction since their emergence in the 1970s. The use of strand-based EWPs can significantly increase the yield of forest resources by utilizing submarginal logs and branches. In this chapter, the strand-based EWPs, including oriented strand board (OSB), laminated strand lumber (LSL), and oriented strand lumber (OSL), are discussed in terms of their fabrication, properties, and uses in construction. Specifically, the manufacturing requirements for elements (i.e., strands), such as dimension, density, and moisture content, are introduced. The major manufacturing processes, such as selection of adhesives, pressing parameters, and thickness control, are also discussed. In addition, the engineering properties and uses of these EWPs are illustrated. Furthermore, some innovative applications of these products, such as hybrid cross-laminated timber, are presented in this chapter.

Low-cycle fatigue life and duration-of-load effect for hybrid CLT fabricated from lumber and OSB

Application of nondestructive test (NDT) methods to assess the condition of metal-tensioned elements in geotechnical engineering applications, including rock bolts, ground anchors, and soil nails, is described. Electrochemical tests, such as measurements of half-cell potential and polarization, were used to detect the presence of corrosion and to evaluate the integrity of corrosion protection systems. Mechanical wave propagation techniques, such as impact and ultrasonic tests, were used to locate features along the length of an element including loss of cross section from corrosion. Interpretation of test results requires knowledge of the electrical continuity between elements being tested and of the details of the installation of the system being evaluated. The utility of the NDTs was evaluated under controlled conditions on bench scale specimens in the laboratory and on buried specimens at a specially developed in situ test facility. However, given the numerous variables inherent to field installations that may have an effect on the measurements, the performance of the NDT technologies needed to be studied in the field. Results from condition assessment employing NDT technologies of tiebacks for a quay wall in Buffalo, New York, and rock bolts along a highway cut in Dresden, New York, are described. Background information is given for each site, including a description of the aggressiveness of the environment relative to corrosion in terms of results from chemical analysis of native soil samples. Results from NDT correlated well with features of the tieback and rock bolt installations. Electrochemical test results indicated that corrosion was occurring, but the wave propagation tests did not indicate any significant loss of cross section. NDT measurements should be archived to serve as a baseline against which future NDT results may be compared.

A suitable defect identification parameter is very important in the field of nondestructive testing (NDT). In this work, we proposed a NDT method which detects the sample’s local contact stiffness (LCS) based on the contact resonance of a piezoelectric cantilever. Firstly, through finite element analysis we showed that LCS is quite sensitive to typical defects including debonding, voids, cracks and inclusions, making it a good identification parameter. Secondly, a homemade NDT system containing a piezoelectric unimorph cantilever was assembled to detect the sample’s LCS by tracking the contact resonance frequency (CRF) of the cantilever-sample system based on strain signals. Testing results indicated that this NDT system could detect the above mentioned defects efficiently. The cantilever-stiffness dependent detection sensitivity was specially investigated and the stiffer cantilevers were found to be more sensitive to small defects. Then, a piezoelectric bimorph cantilever was fabricated and the electromechanical impedance, other than the strain signals, was measured to track the CRF of the cantilever-system. The LCS is then derived by using the equivalent-circuit model. The electromechanical impedance based NDT system is more compact and can be further developed to be a portable device. Finally, a Vicker indenter is fabricated onto the bimorph tip and the contact area is derived from the measured LCS. Thus the NDT system turns to be a hardness tester without any optical devices. It is very useful for in-situ testing or testing on inner surfaces where conventional hardness tester is not applicable.

Nondestructive testing (NDT) includes several highly efficient techniques for the estimation of the physical and mechanical properties of structural timber. However, NDT results are affected by several factors [moisture content (MC), temperature, specimen dimensions, sensor positioning and grain angle, timber-sensor coupling, etc.], of which wood MC is the most important. Scientific research on MC influence in NDT measurements started in the 19thcentury, and 2018 was the first year that a MC adjustment for NDT measurements was published in a European standard (EN14081-2). Although MC influence on NDT has been studied for more than 170 years, MC adjustment factor research is important nowadays because it is widely used in the industry. Currently, NDT device manufacturers develop their own MC adjustment factors adapted to their equipment and species. This paper presents an exhaustive review of MC adjustments for different types of NDT equipment, as proposed by several authors from the 19thcentury to date, and a discussion of factors affecting MC adjustments.

ABSTRACTThis study evaluates three nondestructive testing (NDT) techniques for quality assessment of asphalt pavements. The three NDT techniques examined include an electromagnetic density gauge, a dynamic stiffness gauge, and geophysical surface wave tests for measuring modulus. In-situ NDT tests were carried out for four representative paving projects covering a range of asphalt mixes and traffic loads, and cores were extracted at the centre of each NDT testing location for laboratory measurement of density and modulus. A comprehensive correlation analysis was carried out to examine the performance of each NDT method for quantifying the quality of the asphalt pavements. The in-situ density had a low correlation with the laboratory density and was not sensitive to variations in temperature and asphalt mix type. The in-situ stiffness measured on the asphalt mixtures several hours after paving had a high correlation with the in-situ dynamic modulus and laboratory density, and is therefore recommended as a quantitative property for quality control. Among the three NDT measurements, the in-situ modulus was most sensitive to variations in temperature and asphalt mix type. After correction for temperature effects, the corrected modulus is recommended as a quantitative property for quality assurance.