Field Analysis of Wood Guardrail Post Decay

Thursday, September 19, 2019 - 15:45

Wood guardrail posts can be inspected for decay using a non-destructive testing (NDT) technique called stress wave timing (SWT). This project conducted a field investigation on approximately 500 wood guardrail posts using SWT and then analyzed available data to determine factors that may lead to increased wood decay rates. It was determined that locations with high climate index (> 40) were experience higher decay rates. Additionally, poor preservative retention levels were also found to be associated with high decay rates. Pendulum impact testing concluded that severe decay reduces the fracture resistance of wood posts by more than 50%. The results of this report will be useful in considering approaches to managing WSDOT guardrail assets in the future.  The report is available online at https://www.wsdot.wa.gov/research/reports/fullreports/890-1R.pdf