The aim of the present study is to clarify the mechanical behavlor of a bridge girder during hot galvanizing. The mechanical behavior is analyzed using finite element method (FEM) analysis in which the constitutive equation is given by Bodner's viscoplastic model. The mechanism of zinc induced cracking is also discussed in detall. A shape and size parameter, Rσmax. is proposed and discussed. Rσmax is the ratio of the maximum compressive thermal stress to the elastic buckling stress of the panel and is related to zinc induced cracking. The parameter Rσmax correlates well with the final tensile strain calculated by FEM analysis. Critical strain for crack initiation, εc, was obtained from bending tests and from FEM analysis for several steels. Each value of Rσmax at crack initiation was estimated from comparison with the final tensile strain and εc. The estimated critical value of Rσmax is nearly the same as the critical value of Rσmaxobtained by calculation of the transition from non-cracking to cracking behavior of bridge girders.
