Accelerated corrosion and embrittlement of high-strength bridge wire

Suspension bridge cable inspections have revealed severely corroded and bro ken wires in some main cables. Accelerated, cyclic corrosion studies were c onducted to assess the relative effect of general corrosion, corrosion crac king, and hydrogen embrittlement on the deterioration in material propertie s of high strength steel bridge wire. Galvanized and ungalvanized wire samp les were corroded in a cabinet that cyclically applied an acidic salt spray , dry conditions, and 100% relative humidity at elevated temperatures. Spec imens under zero applied load, and under tensile loads of up to 22 kN (5,00 0 lb) were studied. Mass loss, hydrogen concentration, ultimate load, and e longation at failure were obtained from corroded and uncorroded samples. El ongation measurements indicate a significant embrittlement of the wires, a result supported by fracture surface morphology. Ultimate load was found to degrade at a rate in excess of that attributable to material loss by gener al corrosion. The hydrogen content of corroded wire was found to be greater than that of uncorroded wire, particularly for galvanized wire.