Remaining capacity assessment of corrosion damaged beams using minimum curves

Abstract

The number of exposed steelwork structures used in various industries is steadily increasing as a result of building new structures and extending the life of older structures. Most of these structures are subjected to corrosion due to environmental exposure which can reduce their carrying capacity. Corrosion damage is a serious problem for these structures. Current assessment methods of corrosion damaged steelwork involve visual inspection which tends to be used very conservatively. There is a need for more accurate assessment method which can be used to make reliable decisions affecting the cost and safety. In this paper, various forms of corrosion are reviewed along with how uniform corrosion affects steel structures. Corrosion decay models are developed based on the information on the locations where corrosion occurs. The effects of corrosion on steel beams are analyzed by evaluating the remaining capacity with regard to bending stresses, shear failure, lateral torsional buckling, and bearing failure. Four samples of corrosion damaged beams, which were removed from a chemical works, were measured for their thickness loss and then subjected to load test for their ultimate capacities. The failure loads of the beams are compared with the calculated capacities of various corrosion damage models. In order to estimate the percentage remaining capacity of corrosion damaged I-beams, minimum curves for different types of universal beams which are developed can be used in conjunction with the information on the thickness loss.