Moment modification factors of I-girder with trapezoidal web corrugations under moment gradient

This paper investigates the moment modification factors of an I-girder with trapezoidal web corrugations under moment gradient and various end restraint conditions. The moment modification factors are obtained by using the finite element method with beam elements and new general formulas of cross-section properties as well as a new warping constant of the I-girder with trapezoidal web corrugations. The theoretical results of moment modification factors are successfully verified by comparing them with the results from the commercial finite element software using shell elements. A series of finite element analyses with different corrugation profiles and lengths are investigated. From the results, it is found that the present design of moment modification factor formulas cannot satisfactorily predict the buckling capacities of the I-girder with trapezoidal web corrugations under unequal end moments with various end restraint conditions. For the purpose of design, the closed-form expressions for the moment modification factors are proposed and successfully verified.

► Developed FEM program is used to investigate I-girder with trapezoidal web corrugations under moment gradient. ► Four types of end restraint are considered. ► The moment modification factors from present specifications are over-conservative. ► The closed-form expressions of moment modification factors are proposed for design.