The result of an experimental programme investigating a novel technique to strengthen web plates of steel plate girders against breathing fatigue is presented in this paper. The programme was divided into five phases, including: (1) the development of a novel preformed corrugated FRP panel for strengthening thin-walled steel plate girder webs against buckling, (2) selecting the appropriate adhesive and epoxy using double-lap shear and tension specimens, (3) producing the FRP panel, and (4, 5) testing its performance in two main experimental series. The initial series involved tests on 13 steel plates strengthened with the proposed preformed corrugated FRP panel and subjected to in-plane shear loading using a specially manufactured “picture frame” arrangement designed to induce the appropriate boundary conditions and stresses in the web plates of realistic plate girders; a description of this novel testing approach is included. This initial test series investigated the performance of different forms of strengthening under static load, in preparation for a subsequent series of cyclic tests to investigate their fatigue performance. The test variables included FRP type (CFRP or GFRP), form of FRP (closed or open section), number of FRP layers, and orientation of GFRP fibres used to build the FRP panel. This paper focuses on the second series, in which six specimens were manufactured to simulate the end panel of a 15m plate girder. These were strengthened with the optimized FRP panel from the first series and tested for shear buckling under repeated cyclic loading. Test results and non-linear finite element modelling showed the efficiency of the technique at reducing the critical stresses and increasing the fatigue life of the girders. Finally, the most appropriate strengthening method for fatigue performance is given on the basis of the work presented herein.
|Title of host publication||7th International Conference on Advanced Composite Materials in Bridges and Structures (ACMBS-VII)|
|Place of Publication||Vancouver|
|Publication status||Published - Aug 2016|