Development and characterization of high friction polyurethane bearings for bridge engineering applications

In this study, a high friction polyurethane (HFPU) was prepared using PCL-210 N, MOCA, TDI, and silicone diols. HFPU bearings for bridges were manufactured by casting HFPU in layers onto steel plates. The chemical composition, microstructure, crosslinking strength, and viscoelastic properties of HFPU were characterized. The results demonstrated that HFPU possesses excellent mechanical properties and surface roughness. Mechanical tests showed that HFPU has a hardness of 84 HA, a tensile strength of 35.05 MPa, residual deformation of less than 5 %, and a shear modulus of 2.57 MPa. The HFPU bearings also exhibited excellent vertical load-carrying capacity, horizontal deformation resistance, and recovery capability. Additionally, the Bouc-Wen model accurately simulated the hysteretic behavior, indicating that the HFPU bearings can provide seismic damping effects in bridge structures. The high friction characteristics, characterized by both the Bouc-Wen and Dahl models, showed that the HFPU bearing could work stably within 0-250 % strain.