The National Bridge Inventory (NBI) recognized 86,133 bridges in the United States have no foundation data on record in 2003. It is evident that an unknown percentage of the 86,133 bridges identified by NBI with missing foundation data could also be highly vulnerable to scouring induced by water flow coupled with erodible soils. Conventional excavation, coring and boring excavations to identify unknown bridge foundation depths and types are deemed to be expensive, destructive, and limited in their application to the unknown foundation problem. Many surface and borehole nondestructive testing (NDT) technologies have been developed for this purpose. Three economical proven technique (Sonic Echo/Impulse Response (SE/IR), Parallel Seismic (PS) methods, and Induction Field (IF)) were selected for this study. The study focuses more on SE/IR method since it is the most inexpensive and quick method.
Studies on the applicability and methodology improvement of SE/IR and PS tests have been reported. However, the literature has been mainly focusing on individual pile without the pile cap. This study attempts to reveal practical aspects of the tests, for real bridge foundations including piles underneath pile caps and pier walls.
Equipment for conducting these three NDT tests was available. Preliminary tests under controlled environmental conditions were performed to study the applicability and limitations of these NDT methods. Then, numerous NDT tests were performed on six bridges and one partially dismantled bridge. The foundation depths of two bridges are known in order to validate the NDT results.
A range of factors that affect the success of SE/IR tests were also investigated by finite element simulations. Finite element simulations of 1D wave propagation in square-section timber piles and 3D wave propagation in concrete pier walls and complicated foundations were carried out using ABAQUS/EXPLICIT. The full-waveform inversion method was carried out and the results have been compared against the observed field records. The comparison provides a means of better understanding and conducting the SE/IR tests and interpreting the results.
Finally, the selection of appropriate NDT methods and the guidelines for conducting these nondestructive tests were given in the Procedures Manual attached to this study.
NDT, Foundation, Bridge
New Mexico Department of Transportation
Level of Degree
First Committee Member (Chair)
Dr Tang-Tat Ng
Second Committee Member
Dr Arup Maji
Third Committee Member
Dr Mahmoud Reda Taha
Fourth Committee Member
Dr Yu-Lin Shen
Rashidyan, Saman. "CHARACTERIZATION OF UNKNOWN BRIDGE FOUNDATIONS." (2017). http://digitalrepository.unm.edu/ce_etds/177