AbstractEvaluating the aerodynamic instability of a bridge girder fitted with bridge attachments such as handrails is critical for the wind-resistance design of a long-span bridge. However, the effects of the detailed configuration of handrails on the aerodynamic performance of a bridge girder have not been sufficiently studied. In this study, the heaving vortex-induced vibration (VIV) of a box-girder bridge was evaluated for nongrid and grid-like handrail cases by free vibration wind tunnel tests. The VIV amplitude decreased with the increase in the porosity ratio of handrails. However, the aerodynamic behaviors of the grid-like handrails are different from the nongrid ones. For the nongrid handrails, VIV amplitude was reduced with the increase of the number and the side ratio of middle horizontal bars. For the grid-like handrails, increasing the number of vertical bars have adverse effects on VIV whereas the number of horizontal bars had no influence on VIV. This study also provides new ideas on the optimization of handrail configuration with good aerodynamic properties and the simplification of handrail models for evaluating the aerodynamic properties of a bridge girder in the design process.