Minimum requirements for transverse stiffeners on orthotropic plates subjected to compression

Abstract Bridges with box cross-sections are usually stiffened by the combination of longitudinal and transverse stiffeners. The longitudinal stiffeners are loaded by axial force, and the transverse stiffeners should give sufficient support to them. The design of transverse stiffeners without direct loading can be done by the verification of the minimum stiffness requirements. It has been proved by several researchers in the past that the requirement of the EN1993-1-5 (2005) regarding the out-of-plane bending inertia of the transverse stiffeners is not on the safe side and needs further improvement. At the same time, designers have difficulties in fulfilling the torsional stiffness requirements for the transverse stiffeners using practical stiffener sections. Therefore, the current research program has the aim of harmonizing the minimum requirements for transverse stiffeners and giving applicable design proposals. Complex research strategy and advanced numerical model have been developed to determine the minimum stiffness requirement for transverse stiffeners based on bifurcation analysis and GMNI simulations. More than 3900 simulations have been executed on different geometries to investigate the structural behaviour of the longitudinally stiffened plate and the transverse stiffeners. On this basis a design method has been developed to determine the required minimum transverse stiffener.