Strength reduction curves for corroded seven-wire strands

Steel seven-wire strands are highly vulnerable to corrosion phenomena, which can strongly reduce their strength and ductility capacities. Following several parametric studies already conducted on corroded wires and strands, which allowed to identify the key parameters that govern their mechanical behavior, this paper presents a new resistance model for corroded seven-wire strands. The model introduces a new coefficient that takes into account the variability of the corrosion in the seven wires that constitute the strand, with the purpose of representing the dispersion in the peak strength often emerged from tensile tests available in the literature. The lower bound of this coefficient is estimated analytically considering a brittle behavior for the wires. The ductile behavior is then taken into account by means of several Monte-Carlo simulations of corroded strands. Finally, the resistance model allows to define strength reduction curves that allow to estimate the strength of corroded strands taking into account both the geometry of the corrosion and the steel mate-rial parameters. They represent simple engineering tools that are of great interest from both a design and safety assessment point of view.