The Federal Highway Administration’s (FHWA’s) Advanced Sensing Technology (FAST) Nondestructive Evaluation (NDE) Laboratory is carrying out several new research concepts within its research program.
- Magnetic-based NDE system for corrosion detection internal post-tensioned (PT) tendons and anchorage zones using Main Magnetic Flux Method (MMFM) technique. This system is being developed in the NDE Laboratory in collaboration with Tokyo-Rope. Tendons often contain grout voids, areas that are high risk for future corrosion. Anchorage zones are challenging areas because of massive concrete and the presence of densely-placed reinforcements. Reliable inspection of PT tendons, especially internal tendons and anchorage zones, is the most critical and challenging topic for bridge owners and maintenance engineers. The prototypes being developed employ the same principles as the solenoid-type MMFM system, but the magnetizers utilize a yoke-type configuration with return flux measurement capability to provide sufficient magnetic strength to reach internal tendons through thick concrete cover. At the end of this study, we will know whether magnetic-based NDE technology will work for these critical components.
- Development of field deployable and robotic NDE technologies for assessing the condition of strand and cementitious grout in various types of prestressed concrete structures, such as pretensioned girders, internal and external posttensioned tendons, and anchorage zones. The primary focus of this work is improving the capability of magnetic-based NDE technologies in the most challenging applications.
- Performance evaluation of bridge weigh-in-motion (WIM) systems. The objectives of this project are to identify and compare the accuracy of WIM systems for bridge applications. This evaluation will compare the capabilities with respect to providing repeatable, research-quality measurements of axle weight and spacing, vehicle speed, and identification of vehicle classification for trucks as they pass over bridge structures.
- Develop recipes for concrete reference specimens: the goal of this study is to establish a basis of comparison between specimens, and to develop a framework for a quantitative performance comparison of NDE methods for concrete bridges. Recipes should be established for construction of well-designed reference specimens representing at least four common problems in concrete structures. These four testing problems include corrosion (or section loss) of reinforcement or prestressed tendons embedded in concrete, vertical cracks, delamination, and honeycombs. The recipe procedures are being defined and established in a way that the reference specimen is easily reproducible in any laboratory. These specimens can be utilized for comparing service providers, comparing methods, validation, benchmarking research and development, definition of test task, specification of work, training, and certification.
- Robotic air coupled acoustic array: the ultimate goal of this study will be to develop a noncontact acoustic array that can be deployed on a robotic platform system for accurate and quick imaging of flaws inside concrete bridge decks.
- Document the state of sensors and data collection being used on Unmanned Aerial Systems (UASs) for bridge inspection. The study will also assess the quality level needed to perform a satisfactory inspection. The study is aimed at providing guidance on how the collected data should be assessed, presented, and archived.
- Performance evaluation of concrete bridge deck overlays using nondestructive evaluation techniques: the ultimate goal of this study is to identify and describe the effective and promising NDE techniques that can assess the performance of concrete bridge deck overlays, and detect and characterize deterioration in deck overlays.
- Evaluation of the latest phased array ultrasonic bridge weld inspection technologies and generating the qualification data to enable ultrasonic test techniques to replace the radiography requirements in the American Welding Society (AWS) bridge welding code, D1.5. Tasks include: evaluating full matrix capture (FMC) and total focusing method (TFM) technology to improve AWS D1.5 ultrasonic flaw characterization; ultrasonic modeling to evaluate AWS D1.5 flaw detection performance, including the generation of virtual qualification data using simulation software; and the evaluation of new advanced technologies for potential incorporation in AWS D1.5, including two-dimensional phased array ultrasonic testing (PAUT) arrays and time-of-flight diffraction (TOFD) techniques.
- A magnetic-based NDE system is being for corrosion detection in prestressed concrete structures using magnetic flux leakage (MFL) techniques. The system is being developed in the NDE Laboratory in collaboration with the University of Wisconsin-Milwaukee. The MFL technique is the most effective NDE tool that can detect and approximately quantify the extent of corrosion or fracture of prestressing steel in concrete. The MFL system being developed consists of 2 strong permanent magnets and 64 Hall-effect sensors that measure vertical and longitudinal magnetic field variations caused by corrosion or fracture of prestressing steel in AASHTO concrete I-girders.
- Pavement and tunnel modules for the FHWA NDE Web Manual. The objective of this project is to extend the coverage of the NDE Web Manual to include pavements and tunnels. The NDE Web Manual was conceived as a problem-focused tool to provide concise and unbiased guidance to help practitioners identify the technologies that can serve their specific needs.
- This research develops, evaluates, refines, and ultimately validates a series of integration strategies by examining various data structures, approaches, and modeling techniques to realize the synergies between NDE and structural health monitoring (SHM) assessment approaches. It develops a suite of NDE-SHM integration strategies and approaches to support improved bridge capacity estimates. The predictive capabilities of each of the integration strategies can be evaluated and quantified using data obtained through past field tests. Based on their identified performance attributes, integration strategies will be refined and/or merged.
- Stress assessment plays a crucial role in maintenance and fatigue-life prediction of bridges. This project presents analytical and numerical procedures for estimating intrinsic stresses based on vibration responses of the structure. This vibration-based approach uses classical models and numerical analysis to provide correlations between modal vibration parameters of the structure, i.e., natural frequencies and mode shapes with stresses in the structural model.
- The purpose of a data fusion study is to investigate visualization schemes and fusion of NDE data, and to develop a holistic NDE visualization scheme that (1) conveys meaningful and actionable information about the infrastructure that would trigger an intervention, and (2) is understandable by individuals without an extensive background in NDE. With this focus on visualization, it is of interest to develop NDE data fusion strategies and algorithms that enhance the ability of the data visualization scheme to convey information related to the condition, performance, and safety of bridges.
Updated: Monday, December 2, 2019