Field Deflection Measurements of the No Name Creek FRP Bridge John Held Kansas State University Mechanical Engineering Dept. The No Name Creek FRP bridge in Russell County, Kansas was tested on November 19, 1996. The test consisted of parking the 40kip rear axles of fully loaded dump trucks on the bridge and measuring the deflection at mid-span. The two-lane, 27ft wide bridge has a clear span of 21ft-3in and is constructed of three fiberglass sandwich panels measuring 23ft-3in long and 9ft wide. Deflection data was taken at five points along the mid-span with mechanical dial indicators. The weather was sunny. Temperature at the 2:00PM test was 50. The dial indicators were placed on the mid-span at the north and south edges, at the centerline, and at the joint panels. the dial indicators were zeroed when installed. Zero load deflection readings were recorded just prior to the parking of the first truck. The first truck, with a with a weight of 41,900lbs on the rear tandem axles, was parked facing east in the south lane with the tandem axles centered over the mid span. The outside edge of the tires was 50in from the south edge of the bridge. Deflection measurements were recorded. The second truck, with a tandem axle load of 42,580lbs, was parked in the north lane facing west. Deflections were recorded with both trucks on the bridge. The first truck was then removed from the bridge and deflection data for the second truck alone was recorded. The second truck was then removed and zero load deflections were again recorded. The deflections reported here from north to south along the mid-span have been corrected for the initial non-zero readings of the dial indicators. As the bridge's upper surface warms in the sun, the span bows upward. During the time between noon and 1:30PM the bridge moved upward a much as .090in at mid-span. Total Load Lane Applied N Edge North Joint Center South Joint S Edge 0 0.000 0.000 0.000 0.000 0.000 41900 S -0.015 0.111 0.090 0.120 0.103 84480 N-S 0.145 0.162 0.181 0.143 0.109 42580 N 0.137 0.057 0.099 0.056 0.007 0 -0.011 0.004 0.011 0.002 -0.003 The larger deflections on the north edge can be partially explained by the placement of the second truck closer to the edge of the bridge. This truck also had a slightly higher load. The south panel does seem to be slightly stiffer. this is not an indication of a problem, just an observation. The maximum deflection of .181in with an applied load of 85kip yields a very respectable span/deflection ratio of 1450.