Topic： An Innovative Bridge Inspection Technique through Drive-by Vehicles – A Special Application on Prestress Loss Identification
Time: 9:00-11:00 a.m.,May 29, 2018
Place: Conference Hall in Building 16D
Reporter: Dr. Mijia Yang
Introduction to the report：
Prestress force loss in prestressed concrete bridge is inevitable; however it is the amount of the prestress force loss matters, which determines the safety of load-carrying members. More than 60% of all new and replaced bridges built in US are prestressed concrete bridges since the year 2000, which demands a fast and accurate inspection technique to monitor their prestress loss.
The existed direct and indirect methods used for prestress loss identification are all based on the measurement collected from sensors deployed on the outside or inside of the bridge, which is not only costly but also inconvenient. The current study proposes to detect the prestress force loss of the bridge through the analysis of vehicle responses, in which the principle of virtual works was adopted to take the effect of prestress into consideration. Through simulations, it is found that vehicle vertical acceleration shows a strong correlation with the prestress loss and light, low-frequency vehicles moving at low speeds have a better performance in detecting the bridge prestress loss than the heavy, high-frequency vehicles with high speeds. The advantage of the proposed method is that it only needs a few sensors installed on the vehicle, and works without interrupting the ongoing traffic. Based on the validated modeling results, the suggested technique provides an efficient and cost-effective tool for state agencies to maintain a large amount of prestressed bridges. Introduction to the reporter:
Dr. Mijia Yang, P.E., was a tenured associate professor at Department of Civil and Environmental Engineering, North Dakota State University. Dr. Yang received his Ph.D in Structural Engineering from the University of Akron in 2006 and another Ph.D in Rock and Tunnel Engineering in 1999 from China University of Mining and Technology. Before joining NDSU, he worked as an assistant professor at the University of Texas at San Antonio for four years, and was a postdoctoral researcher at the University of Nebraska-Lincoln from May 2006 to July 2007.
Dr. Yang has practiced teaching and research broadly in structural engineering. He has taught Steel Design, Dynamic of Structures, and several others for the last 5 years. His research concentrates on impact and blast protection with advanced engineering materials, multi-scale modeling of composite and concrete materials, smart health monitoring in Civil Infrastructure, and self-healing concrete. His representative work included developing a systematic design method for impact barriers, a unified fatigue criterion for uniaxial Polyurethane E-Glass composite laminates, damage detection through guided wave, and a creep design methodology for Epoxy bonded anchor systems. Dr. Yang has participated in several state and national projects during his career, including “Effect of intermediate diaphragms on prestressed concrete bridge girders for over-height truck impacts” and “Testing of window connections specially designed for blast loading”. Dr. Yang also won several national and international awards, including the Philip E. Rollhaus, Jr. Roadway Safety Essay Contest held by Quixote in 2005, the faculty research award at the University of Texas at San Antonio in 2007, the ASCE travel award in 2005, and the ASCE Journal of Aerospace Engineering Outstanding Reviewer award in 2012. Dr. Yang is currently serving as the associate editor of Journal of Materials in Civil Engineering, ASCE, and has more than 100 publications, including journal papers, conference papers, and reports in the field of composites, structural testing and characterization.