On the out-of-plane stiffness of I-section girders with corrugated webs using elastic finite element analyses

Abstract

Corrugated web girders (CWGs), nowadays, are widely used as bridge girders all over the world thanks to their superior shear resistance compared to I-girders with transversely-stiffened flat webs (IPGs). Additionally, it has been recently found that the out-of-plane stiffness of CWGs increases their lateral-torsional buckling resistance. However, based on the authors' experience, the literature does not contain a calculation method which ensures that the out-of-plane stiffness of CWGs is higher than that of IPGs. Accordingly, this paper is devoted to provide such method for design purpose. This investigation is based on the elastic buckling analyses of CWGs, by using ABAQUS solver, which provide the critical finite element (FE) strengths. Then, two critical moment predictions are calculated; the first one uses the method derived by Moon, et al. (2009), whereas the other one is that calculated typically for IPGs. While the first considers an enhanced warping constant due to the corrugations, the later does not. From the comparisons, the strengths considering the prediction of Moon, et al. (2009) are found to represent well FE strengths in some cases; meaning that the out-of-plane stiffness of CWG is higher than that of its equivalent IPG. Accordingly, the contribution of CW in the warping constant is divided by that of the entire cross-section of IPGs to find the effective ratio that yields higher out-of-plane stiffness for CWGs compared to IPGs. Based on these statistics, a condition is put forward which ensures that CWGs own higher out-of-plane stiffness. This paper proves that CWGs do not always have higher out-of-plane stiffness compared to their equivalent IPGs, but ensuring this requires to link the dimensions of CW, especially the value of corrugation depth, with the flange width.