Failure behaviour of radial spherical plain bearing (RSPB) joints for civil engineering applications

This paper presents a comprehensive study on the failure behaviour of structural joints employing radial spherical plain bearings (RSPBs). The research program commenced with an experimental study looking into the performance of the RSPBs and the associated joints. Two major failure modes, namely, brittle fracture of the inner ring and brittle crack of the outer ring, under radial and thrust loads, respectively, are found for the RSPBs. Conservative predictions are given by the nominal radial load rating, with the ultimate load-to-load rating ratio ranging between 1.27 and 1.79. The nominal thrust load rating for the RSPBs also tends to be conservative, where the ultimate load-to-load rating ratio ranged between 3.01 and 3.48. For the joint behaviour, the main source of inelastic deformation was provided by yielding of the pin shaft, and as a result a reasonable level of joint ductility is exhibited, but the contact between the pin shaft and the bearing could result in brittle fracture of the bearing. The RSPB joints are also shown to have very stable load resistance performance under a constant high load level lasting for 1 h. A numerical study is subsequently conducted, and the deformation and damage mechanism of the joints and its key components are further analysed. Based on the test data and numerical investigations, some design recommendations have been proposed for the RSPB joints.