Equivalent flat-web thicknesses and modified flange-based moment resistance for corrugated-web steel I-girders

This study proposed analytical formulations for equivalent flat-web thicknesses at horizontal and inclined fold sections and modified flange-based moment resistance for corrugated-web girders (CWGs), accounting for the accordion effect due to corrugations. The finite element (FE) analysis approach was used for examining the nonlinear flexural behavior of CWGs. Numerical models were first validated against flexural tests from two documented CWG studies. For additional verification, nonlinear theoretical analysis of flat-web girders was compared and verified against detailed FE-based analysis results. A detailed parametric study was performed to examine the effect of corrugated-web trapezoidal profiles and girder geometry on the moment resistance of CWGs using the validated nonlinear FE modeling. Then, the parametric study results were used in the theoretical nonlinear moment-curvature analysis on equivalent flat-web girders to derive the proposed formulations for flat -web thicknesses at horizontal and inclined fold sections of a CWG. Alternatively, a modified flange-based moment resistance formulation was proposed for CWGs by accounting for the accordion effect of their trape-zoidal corrugated webs. Both the proposed formulations simplified the accordion effect analysis in CWGs and can result in potentially economical girder designs and further development of design specifications for CWGs.