Friction Coefficients for Slide-In Bridge Construction Using PTFE and Steel Sliding Bearings

Abstract

Slide-in bridge construction (SIBC) has been used in accelerated bridge construction (ABC) for the last decade. Slide-in bridge construction is carried out using bearing pads consisting of polytetrafluoroethylene (PTFE) and steel sliding surfaces. In this study, coefficient of friction (COF) measurements were made with variable surface roughness, lubrication type, sliding speed, and contact pressure. Among three tested surfaces, the rough rolled stainless steel and the carbon steel produced COF values much higher than those of stainless steel with a #2B surface. Unlubricated and graphite-lubricated surfaces resulted in very high friction values, whereas the values for soap, grease, and oil were comparably lower. The oil and grease tests gave the lowest friction values, 0.90–4.04% and 0.67–5.15%, for the studied contact pressures, respectively, and are recommended for future use. Higher contact pressures typically resulted in lower COF values. Overall, the currently recommended COF values underpredict the COF compared with the results from this study. However, for higher contact pressures, this study found lower COF (e.g., for high pressure of 55 MPa, 2% versus 0.9–1.44%) compared with current recommendations and the opposite for low contact pressures (e.g., for 11 MPa, 2.71% versus 4.04–5.66%). Unlubricated sliding surfaces are not recommended due to the large scatter in comparable data in this study and the literature.