Profile control of large-span tapered girder bridges with corrugated steel webs during cantilever construction progress

For large-span tapered girder bridges with corrugated steel webs (CSWs) constructed using the cantilever method, the cantilever phase is critical for controlling the bridge's profile, as deflection increases with each segment erected. This necessitates setting the pre-camber and making dynamic adjustments to ensure that the bridge's profile aligns with the design specifications. Existing standards for pre-camber calculation assume that the flexural rigidity of girders with CSWs is provided solely by the concrete top and bottom flanges, with the CSWs only bearing shear forces. However, this study reveals that in tapered girders with CSWs, bending moments also induce additional shear forces, leading to additional shear deflection in the CSWs. This additional deflection progressively accumulates as each segment is erected, significantly influencing the bridge's overall deflection. Consequently, if pre-camber is set according to existing standards, it may lead to the actual pre-camber exceeding the design value, resulting in significant errors and potentially preventing the final closure of the bridge. This study introduces, for the first time, a novel, modified pre-camber calculation method for tapered girders with CSWs, which incorporates both the shear deflection due to shear forces and the additional shear deflection induced by bending moments in the CSWs. The validity of this approach is verified through scaled specimen testing and finite element (FE) analysis. The modified pre-camber method was subsequently applied to an actual tapered girder bridge with CSWs, revealing that using the basic method in existing standards could result in a pre-camber error of up to 33.28 % at the support sections and 11.33 % at the mid-span sections.