Study on a curvature compensation method for improving the end face matching of large-segment steel box girders during full-span erection

As precast segments are increasingly preferred for bridge construction owing to their efficiency and environmentally benign attributes, this study aims to enhance the end face matching technology for large-segment steel box girders. The curvature compensation method, which is a form of extension of the elevation compensation for pre-camber setting, is proposed based on the unstressed geometry of the steel box girder. It is found that the curvature compensation is equivalent to the end face angle compensation of segments if the construction technology of "combining several straight lines into a curve" is adopted. Three practical formulas for calculating curvature compensation angles are derived, namely, the moment method, intersection angle secant method, and incremental moment method, and theoretical values of the errors caused by using matching line shape calculation are provided. Furthermore, considering the specific continuous bridge with large-segment steel box girders in the Shenzhen-Zhongshan Channel as a case study, the calculation results of manufacturing parameters, matching line shapes, and end matching are presented. The findings indicate that the curvature compensation angle's maximum error reaches 55.7 % when calculated conservatively using erection geometry, while the manufacturing geometry's maximum error reaches 4.84 cm if the curvature compensation angle is disregarded. The results of on-site monitoring show that the curvature compensation method proposed in this study is able to provide the continuous fabrication geometry and achieve the perfect matching of end faces of neighbouring large-segment steel box girders.