Presented: September 19, 2018, 11:00 AM Central Time
Speaker: Dr. Jizhong Xiao, Professor, The City College of New York
In addition to visual inspection for surface flaws, inspectors are often required to detect subsurface defects (e.g., delamination and voids) using nondestructive evaluation (NDE) instruments, such as ground penetration radar (GPR) and impact sounding device, in order to determine the structural integrity of bridges and tunnels. In these cases, access to critical locations for reliable and safe inspections is a challenge.
Since 2002, Dr. Jizhong Xiao’s group has developed four generations of wall-climbing robots for NDE inspection of bridges and tunnels. These robots combine the advantages of aerodynamic attraction and suction to achieve a desirable balance of strong adhesion and high mobility. For example, Rise-Rover with two drive modules can carry up to 450 N payload, and GPR-Rover can carry a small GPR antenna for subsurface flaw detection and utility survey on concrete structures. These robots can reach difficult-to-access areas (e.g., the bottom side of bridge decks), take close-up pictures, record and transmit NDE data to a host computer for further analysis. They can potentially make bridge inspection faster, safer, and cheaper without affecting traffic flow on roadways.
This presentation will review the recent development of smart and autonomous wall-climbing robots to realize automated inspection of civil infrastructure with minimal human intervention.
Dr. Jizhong Xiao is a Professor in the Electrical Engineering Department at The City College of New York, the flagship campus of the City University of New York. Dr. Xiao's research interests include robotics and control, cyber-physical systems, non-destructive evaluation (NDE) of infrastructures, autonomous navigation and 3D simultaneous localization and mapping (SLAM), real-time and embedded computing, assistive technology, multi-agent systems and swarm robotics.
Presented: June 21, 2018, 12 p.m. Central Time
Speaker: Dr. Hung La, Assistant Professor, University of Nevada, Reno
Steel structures and steel bridges, constituting a major part in civil infrastructure, require adequate maintenance and health monitoring. In the U.S., more than 50,000 steel bridges are either deficient or functionally obsolete, which likely presents a growing threat to people's safety. The collapse of numerous bridges recorded over the past 16 years has shown significant impact on the safety of all travelers.
In this presentation, the design and implementation of two different climbing robots for steel structure inspection are reported. Based on the magnetic wheel design, the robot can climb on different steel surface structures (i.e., flat, cylinder, cube). The robots can be remotely controlled or programmed to move autonomously on steel structures. Current tests shows that the robots can carry up to 8 pounds of load while being able to adhere strongly on the steel surface. Climbing capability tests are done on bridges and on several steel structures with coated or unclean surfaces. Although the steel surface is curved and rusty, the robots can still adhere tightly.
Dr. Hung La is an Assistant Professor of Computer Science and Engineering at the University of Nevada, Reno, Director of the Advanced Robotics and Automation Laboratory, and principal investigator for the INSPIRE UTC. He works in the areas of robotics and control systems. His current interests are in bridge inspection robotic system developments, mobile sensor networks, and multi-robot systems. Dr. La is an associate editor of the IEEE Transactions on Human-Machine Systems. Dr. La has received the prestigious 2014 ASCE Charles Pankow Award for the development of Robotics Assisted Bridge Inspection Tool (RABIT). He is the recipient of 3 Best Paper Awards and a Best Presentation Award at international conferences.
Presented: March 15, 2018
Speaker: Dr. Reza Zoughi, Schlumberger Endowed Professor, Missouri S&T
The relatively small wavelengths and large bandwidths associated with microwave signals make them great candidates for inspection of construction materials and structures, and for materials characterization and imaging. Signals at these frequencies readily penetrate inside of dielectric materials and composites and interact with their materials characteristics and inner structures. Water molecule is dipolar and possesses a relatively large complex dielectric constant, which is also highly sensitive to the presence of ions that increase its electrical conductivity. Consequently, chemical and physical changes in construction materials affect their complex dielectric constant. This can be measured, and through analytical and empirical dielectric mixing formulae, correlated to those changes. Examples of applications would be, presence of delamination in a bridge deck and pavement, permeation of moisture behind retaining walls or corrosion of reinforcing steel bars which can be imaged with microwave techniques. One of the critical trade-off issues is between the microwave signal penetration into concrete vs. frequency of operation. Dielectric of concrete, particularly when moist, has a relatively high loss factor. As such, lower microwave frequencies are suitable to achieve reasonable penetration. Image resolution degrades as a function of decrease in operating frequency, therefore, a balance must be reached when using these techniques for imaging cement-based materials. In this webinar, issues related to concrete materials property evaluation and high-resolution imaging will be discussed, and examples will be provided.
Dr. Reza Zoughi
Schlumberger Endowed Professor
Electrical and Computer Engineering Department
Director, Applied Microwave Nondestructive Testing Laboratory (AMNTL)
Missouri University of Science and Technology (Missouri S&T)
URLs: http://amntl.mst.edu/people/zoughi/zoughi2/, http://amntl.mst.edu/
Dr. Reza Zoughi is the Schlumberger Endowed Professor in the Electrical and Computer Engineering department at Missouri S&T. Dr. Zoughi’s research activities are broad many of them are in the area of civil structure evaluation and imaging involving materials characterization of cement-based materials and structures, detection and evaluation of alkali silica reaction (ASR) and gel formation, and imaging of rebars for detecting corrosion. He had his research team have developed high-resolution, portable 3D microwave camera suitable for a number of critical applications. Dr. Zoughi holds 18 patents in the field of microwave nondestructive testing and imaging.