TTI Research Supervisor:
Chiara Silvestri Dobrovolny, Ph.D.
Associate Research Scientist
Texas A&M Transportation Institute
College Station, Texas 77843-3135
(979) 845-8971 [email protected]
Pooled Fund Technical Representative:
Assistant Bridge Design Administrator
Bridge and Structural Design Section
Louisiana Transportation Center
1201 Capitol Road
P.O. Box 94245
Baton Rouge, LA 79084-9245
(225) 379-1323 [email protected]
The recently approved Test Level-3 F-shaped precast Louisiana concrete barrier detail has a slotted hole design that allows for shifting of the pin to avoid transverse reinforcement. To avoid rebar in the longitudinal direction, contractors would be required to physically shift the barrier transversely. Contractors often complain that it is often difficult to avoid conflicts with the reinforcing steel.
Non-Destructive Testing (NDT) methods are popular for routine inspection of bridge members. With the ability of new highly technical systems, some of these NDT techniques can be used for reinforcing steel rebar location in concrete bridge decks without destruction of the members being tested. Use of these techniques has the ability to minimize traffic restrictions related to field data collection and to improve design and asset management. These advanced inspection techniques can be expensive due to the need of having professionally trained technicians to perform the testing and to acquire and analyze the inspection results. Examples of NDT techniques that can be used for rebar location are Ground-Penetrating Radar (GPR) and magnetic devices such as covermeters.
The objective of this study was to determine the current NDT methods available for detecting locations of the reinforcing steel in bridge decks. Using NDT methods contractors can accurately locate the placement of the concrete barrier rails in reference to reinforcing steel during construction. Each method was researched to determine advantages and disadvantages. Different devices were studied for comparison of accuracy in detecting rebar location and concrete coverage, ease of use, and training required to operate.