Determination of Bridge Design Parameters through Field Evaluation of the Route 601 Bridge Utilizing Fiber-Reinforced Polymer Girders

The Route 601 Bridge in Sugar Grove, Virginia, spans $11.89\mathrm{m}$ $\left(39\mathrm{ft}\right)$ over Dickey Creek. The bridge is the first to use the Strongwell $91.4\mathrm{cm}$ $\left(36\mathrm{in.}\right)$ deep fiber-reinforced polymer double web beam in a vehicular bridge superstructure. Construction of the new bridge was completed in October 2001 and field testing was undertaken shortly thereafter, as well as in June of 2002, to assess any potential changes in structural performance. This paper details the field evaluation of the Route 601 Bridge. Using midspan deflection and strain data from the October 2001 and June 2002 field tests, AASHTO bridge design parameters were determined—namely, wheel load distribution factor $g$ , dynamic load allowance $IM$ , and maximum deflection. The wheel load distribution factor was determined to be $S∕4$ , a dynamic load allowance was determined to be 0.36, and the maximum deflection of the bridge was $L∕\mathrm{1,110}$ . Deflection results were lower than the AASHTO $L∕800$ limit. This discrepancy is attributed to partial composite action of the deck-to-girder connections, bearing restraint at the supports, and contribution of guardrail stiffness. It was found that diaphragm removal had a small effect on the wheel load distribution factor.