Restoring NBIS Compliance Through Large-Scale Foundation Evaluation

BDI partnered with the Louisiana Department of Transportation and Development (LADOTD) to evaluate the foundation configuration of nearly 350 bridges across Districts 02 and 62 as part of the agency’s ongoing bridge inspection and asset management program. Because each bridge carried an Unknown Foundation rating from previous inspections, the LADOTD needed to determine foundation data to assess the scour vulnerability and achieve compliance with NBIS Item 113 requirements.

BDI conducted extensive field investigations and applied a combination of Ultraseismic Testing (US), Sonic Echo/Impulse Response Testing, and Parallel Seismic Testing to determine the length and integrity of timber, steel, and concrete foundation piles. These nondestructive testing methods allowed BDI to evaluate foundation conditions and scour susceptibility without extensive excavation.

Before launching the full-scale program, BDI validated its testing methodology by measuring 18 known piles and achieving results within the required ±10% accuracy tolerance. BDI then developed a custom, semi-automated workflow that streamlined data analysis, CAD production, report generation, and scour rating calculations. Over six months, BDI tested and evaluated more than 1,000 foundation piles across the bridge inventory.

Using the collected data, 93% of the bridges were able to be reclassified as Scour Stable and 7% as Scour Susceptible, giving LADOTD the information needed to prioritize maintenance activities and allocate resources more effectively.