Assessing local stresses in crane runway girders considering the rail support

This paper introduces a design model for predicting local stresses in the web plates of I-section crane runway girders. A critical review of current design procedures reveals two principal shortcomings: (i) the role of the elastomeric bearing pad between the rail and the top flange is insufficiently accounted for, and (ii) existing methods cannot adequately capture the longitudinal distribution of local stresses. To address these gaps, new analytical expressions are developed and calibrated. The stiffness characteristics of elastomeric bearing pads are quantified through laboratory compression tests. Full-scale experiments on a crane runway girder are conducted to measure local strains and to assess the influence of both the bearing pad and geometric imperfections at the rail-flange interface. A comprehensive finite element parametric study is then used to calibrate and validate the analytical model. The resulting design model accurately reproduces local stress fields in contrast to current standards. It enables more economical girder designs by explicitly considering the beneficial effects of elastomeric bearing pads. Furthermore, the new design model provides a simple, standards-compatible modification (based on established analytical solutions) for both cases (elastomeric or rigid rail support).