NDE System for Determining Wood Guardrail Post Integrity
PI: Donald A. Bender (WSU), bender@wsu.edu
Dates: 07/01/2013 – 7/31/2015
Final Project Report: PacTrans-31-WSU-Bender
Wood guardrail posts degrade over time due to decay, insects and weathering, and the Washington State Department of Transportation (WSDOT) needs an inspection system to determine the condition of posts along our highways to effectively prioritize future investments in guardrail upgrades. There are approximately 1.5 to 2 million guardrail posts on the state highway system. Post inspection methods at WSDOT have never been uniformly defined, and the inspection opportunities have normally been associated with pavement preservation projects. Combined with a parallel WSDOT study, the goal is to develop a reliable, cost-effective nondestructive evaluation (NDE) procedure for inspecting wood guardrail posts. The proposed stress wave NDE system will address deficiencies in current equipment with regard to ease of use and worker safety; efficient ways to acquire/store/transmit data; along with heuristics to interpret data and guide decision-making on guardrail maintenance and replacement. Specific objectives are to: (1) Work with an industrial partner on a new prototype stress wave instrument with features to consistently initiate stress waves; inspect posts below grade; store stress wave transit times, global positioning system (GPS) coordinates and time; and transmit data to a cloud server. (2) Characterize the prediction accuracy and reliability of the proposed NDE system. (3) Work with WSDOT representatives to integrate NDE data collected in the field into their geographic information system (GIS) system to help guide maintenance decisions with other GIS layers of information. (4) Conduct field trials and time-motion studies to obtain worker feedback with regard to training, ease of use, safety implications and feedback for improving the system.
