Use of Fiber-Reinforced Polymer Composite Elements to Enhance Structural Steel Member Ductility

An innovative use of fiber-reinforced polymer composite materials to control the manifestation of local buckling in a steel section during plastic hinging is discussed in the present work. This discussion focuses on a technique wherein the constituent plate components in a steel I-shaped cross section are braced against local plate buckling modes through the imposition of thin longitudinal strips whose function is to enforce a nodal line along a plate element. This work demonstrates that such an approach increases the critical load for individual steel plate elements and helps to constrain plastic flow for these same elements so that the structural ductility of the overall cross section is enhanced. The research work discussed herein is analytical in nature. Detailed nonlinear finite element models are created using traditional techniques implemented on the commercially available software system ADINA. Specifics pertaining to bond-line response are not treated.