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Razinger, Jonathan

Mechanical Engineering

2014

MS

Every second, millions ofAmericans depend on a vast U.S. infrastructure that extends from coast to coast and is exceeding its design life. The health and state ofthe concrete roadways and bridge decks that commuters rely on a daily basis can be efficiently examined and monitored with the use of ground penetrating radar (GPR). Repair and maintenance of these concrete structures is slow and expensive. The development and implementation of a faster and more reliable, near to mid field, air-coupled phased-array GPR system would help to solve these two problems. The objective of the study was to see how accurately the phased-array system can detect subsurface objects and corrosion. A concrete stab with an embedded object was used to simulate a concrete bridge deck or roadway. The concrete slab was placed under the phased-array radar system which emitted electromagnetic energy into the slab and the reflected signal was analyzed to see if the system can detect subsurface objects like rebar which can often be found in concrete structures.
The results show that varying the frequency, height and orientation of the source antennas increases or decreases the magnitude of the return signal. This study outlines which configuration of parameters best optimizes the phased-array system's ability to detect subsurface objects. The reflected signals gathered from the experiments were also compared to a theoretical model of the phased-array's reflected signal providing valuable information on the systems performance and provide concepts for improved designs. A commercial phased-array GPR trailer could be built in the near future that could scan and detect delaminations, cracks, voids and corrosion of concrete roadways and bridge decks with faster data collection capabilities due to the phased-arrays electronic sweeping feature.