This standard specifies the requirements for materials, design, manufacturing, and testing of spherical and cylindrical bearings for bridges. It provides design values for PTFE, stainless steel, and other components, and details the acceptance criteria to ensure the bearings can accommodate translational and rotational movements under design loads.
Specifies material, design, manufacturing, testing, and acceptance requirements for spherical and cylindrical bearings used in bridges.
Quick Reference Values
Maximum contact pressure on dimpled lubricated PTFE45 N/mm²
Minimum thickness of stainless steel sliding sheet1.5 mm
Characteristic coefficient of friction for dimpled PTFE0.03
Minimum projection of PTFE from its recess2.0 mm
Minimum ambient temperature for design (unless specified otherwise)-20 °C
Minimum hardness of stainless steel sheet130 HV10
Key Formulas
N_Sd / A_eff <= f_d,ptfe — Check for compressive stress on PTFE
μ_max = f_b * f_t * f_α * f_e — Calculation of maximum design coefficient of friction
α_d = (N_Sd / K_r) + α_add — Design rotation demand
Practical Notes
Spherical bearings accommodate rotation about any horizontal axis, whereas cylindrical bearings permit rotation about a single axis only. This choice is critical and depends on the bridge's articulation scheme.
Installation precision is paramount. Any misalignment or improper grouting can lead to eccentric loading, premature wear, and failure of the bearing.
The design of the guidance system to resist horizontal forces is as important as the bearing itself and must be considered integrally with the bearing selection.