Session: 15-01-01: ASME International Undergraduate Research and Design Exposition

Paper Number: 151462

151462 - Evaluation and Practical Assessment of Ground Penetrating Radar (Gpr) for Bridge Deck Assessment 

Abstract:
The ability to evaluate civil structures without altering or damaging the materials is becoming increasingly important and useful for infrastructure maintenance. The technique to analyze and test materials for weaknesses without causing destruction is referred to as non-destructive evaluation or testing. Specifically, a common method of this type of inspection is called ground penetrating radar (GPR), which is desired in many construction applications. With the use of electromagnetic energy, GPR has the capability to locate buried objects in materials because of the differences in electrical and magnetic properties that are encountered. Valuable data can be obtained on these subsurface objects, allowing for an understanding on the properties and making proper judgment on the structure possible. This study explores the approaches in which GPR has been implemented for the assessment of the bridge deck in southeast United States. Through different data acquisition and processing techniques, results show that GPR is very successful in collecting information to verify the state and condition of these materials.

Introduction:
A popular non-invasive technique that is based on the principles of electromagnetic energy pulses is ground penetrating radar (GPR). This radar technology has been employed in a variety of practices like archaeological and forensic investigations, but GPR is proving to be a powerful Electro-Magnetic (EM) approach for the monitoring and maintenance of infrastructure due to the portability and effectiveness it has to offer. Specifically related to construction applications, GPR has the potential to assess the conditions of pavement, buildings, bridges, railways, soil, and buried pipes. GPR instruments have been widely used to properly survey buildings and bridges for evaluation, making it possible to understand the condition and safety of
the structure. For the assessment of reinforced concrete structures, the GPR method can be applied comparably to buildings and bridges as it is possible to obtain information on the rebars. GPR devices can survey pillars, beams, floor slabs, girders, and bridge decks. This study analyzes the application and practicality of GPR nondestructive testing (NDT) for bridge inspection in the field applications. The method implemented is GPR for locating the embedded reinforcement steel and suspected areas of concrete deterioration caused by rebar corrosion. Core specimens were extracted for visual inspections to compare with the GPR data. Additionally, compressive tests were completed to obtain the compressive strength of the bridge deck. This data was compared to results from the localized GPR inspection results. All of these NDT methods were influential in evaluating the bridge deck since no design drawings were available due to the bridge being built in 1941. Through data analysis, the results were compared primarily with the GPR and actual core data. This study displays the limitations when using NDT methods in a practical situation as opposed to laboratory settings. The uncertainty of what
objects and flaws are embedded beneath an element poses some challenges; therefore, having the appropriate knowledge and background on NDT methods is necessary for structural evaluations.

Methodology:
To conduct the experiment to complete this project, the following steps were taken:
 An x-y gird like system was set up to conduct scans across two spans.
 GPR scanning was completed using a Proseq GPR system and was analyzed for rebar
corrosion.
 GPR scanning was completed using a GSSI system and was analyzed for rebar corrosion.
 Coring was completed for the validation of suspected rebar corrosion locations.
 A comparison was made between the Proseq and GSSI GPR systems.

Presenting Author: Josie Gunter Georgia Southern University

Presenting Author Biography: Josie Gunter is a sophomore Mechanical Engineering student at Georgia Southern University. She currently completes undergraduate research in the LANDTIE Lab exploring Nondestructive Testing for the Georgia Department of Transportation to create safer transportation infrastructure. She serves as the Vice President of the American Society of Nondestructive Testing- Coastal Georgia Section and plans to pursue graduate education upon the completion of her bachelor's degree.

Authors:

Josie Gunter Georgia Southern University
Elsie Lappin Georgia Southern University
Vicktor Helgason Georgia Southern University
Hossein Taheri Georgia Southern University
Saman Hedjazi Georgia Southern University