The goal of this study was to determine the feasibility of using a commercially produced 2 inch deep fiber-reinforced polymer (FRP) plank with a 0.75 - 1.0 inch cast-in-place concrete or cement board compression flange as a replacement for conventional timber 3" × 12" decking bridge deck for pedestrian or light-weight vehicle bridges (such as snowmobiles or snow removal tractors.) A number of different specimens were fabricated and tested in three point bending experiments. Bonded, cast-in-place and mechanically fastened concrete and cement board compression flanges were investigated. The stiffness and strength of the hybrid deck panels were compared with that of a conventional 3" × 12" timber deck panel. Failures were due to debonding between the pultruded plank and the concrete or cement-board compression flange or due to crushing of the compression flange. Preliminary analysis reveals that the hybrid plank can lead to support spacing of about 6% more than allowed with 3" × 12" timber planks based on a deflection limits. Flexural strength was similar to the timber beams. The beams with the cement-board compression flanges were about 75% the strength of the timber beams per foot width while the beams with the concrete compression flanges were about 55% the strength of the timber beams per foot width, for the specific geometries of the specimens tested in this research. However, since the deflection controls the design of these panels a safety factor larger than 2.5 can still be maintained for these deck panels assuming lightweight vehicles up to 2 tons.
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