Welded residual stresses in corrugated steel webs: Theoretical and experimental analyses

As bridge design tends towards longer spans, reducing the structural dead load has become a key challenge. The corrugated steel web (CSW)–prestressed concrete composite box girder is an innovative steel–concrete composite structure that effectively reduces the bridge substructure's dead load by reducing the weight of the main girder. However, during CSW welding, thermal deformation due to localised high temperatures is limited by the stiffness of the weldment, and residual welding stresses are generated in the weldment. These stresses can adversely affect the serviceability and construction accuracy of composite bridges. Therefore, in this study, the welding process used for fabricating CSW combined box girders was theoretically analysed and experimentally investigated. First, the generation and distribution of welding residual stresses were analysed, and a calculation method for the residual stresses was derived. Subsequently, a CSW box girder specimen was subject to the welding process, during which temperature and strain tests were performed; the analysis of the measured data revealed changes in temperature and strain during welding. Further, a finite element model for CSW welding was established, and the accuracy of the model was verified by comparison with the measured data. Finally, based on the derived residual stress calculation formula and verified finite element model, a nonlinear buckling analysis of the corrugated web was performed, and the failure mode and load–displacement curve of the corrugated web were derived. The results indicated that weld residual stresses more accurately predicted the results than initial structural defects used in traditional specification methods. •Welding process of corrugated steel web theoretically and experimentally investigated.•Welding residual stress calculation method proposed.•Method more realistic than existing methods for modelling initial defects.•Effects of welding residual stress on buckling performance of a web plate revealed.•Method provides a scientific basis for engineering design and construction.