ABSTRACT
This paper presents the test results of a research study on the feasibility of using nondestructive test (NDT) methods for the determination of unknown depths of bridge foundations. Of the over 580,000 highway bridges in the National Bridge Inventory, 104,000 of these bridges are over water and have both unknown foundations and consequently, unknown foundation scour risks. Foremost is the need to determine the foundation depth and then foundation type (footings or piles), geometry, and subsurface conditions. A comprehensive evaluation was made of potential NDT technologies that have relevance to this problem, of which only the surface-based Sonic Echo/Impulse Response and Flexural Wave methods for timber piles, and the borehole-based Parallel Seismic and Induction Field methods had been previously used to determine foundation depths.
This study documents the results for two acoustic NDT methods of Ultraseismic (a proposed new test method), and the Parallel Seismic test method which were found to have the broadest application to the investigated concrete, timber, and steel bridge substructures.
