Civil Engineering ETDs

Publication Date

Summer 7-15-2017

Abstract

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.

Keywords

NDT, Foundation, Bridge

Sponsors

New Mexico Department of Transportation

Document Type

Dissertation

Language

English

Degree Name

Civil Engineering

Level of Degree

Doctoral

Department Name

Civil Engineering

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

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