Impact of Tendon Placements on Shear Lag Phenomenon in PSC Box Girders

PSC box girders are extensively employed in Modern bridge construction because of their efficiency in structure, torsional rigidity, and durability. Shear lag, however, tends to produce non-uniform stress distributions over the flanges, resulting in local stress concentrations, compromised flexural effectiveness, excessive deflection, and possible cracking. This research focuses on the effect of tendon position on shear lag behavior in a two-span continuous PSC box girder. Six tendon geometries were compared under uniform geometry, material response, and typical bridge load conditions. Results show that the optimized tendon layout enhances uniformity of stress with 35% reduction in shear lag, along with 26% and 21% reductions in peak bending moments and maximum deflections, respectively. Placement of tendons close to critical web-flange connections improves the transfer of loads, structural rigidity, and performance of the bridge. The conclusions give the advice in designing lighter, shorter-span, and more performing PSC box girders.