On the influence of corrosion on the force-displacement behaviour of steel wires and strands

Steel seven-wire strands are highly vulnerable to corrosion phenomena, which can strongly reduce their strength and ductility ca-pacities. In the present work, the key parameters governing the mechanical response of corroded wires and strands are identified. They include parameters related to both the geometrical configuration of the corrosion (in terms of reduction of cross-sectional area and longitudinal extension) and to the material constitutive model (strength, hardening and ductility). In this respect, both elastic-perfectly plastic and bilinear with hardening models are considered for the steel material. A simplified mechanical model describing the tensile force-displacement behavior of corroded wires and strands is proposed. The corroded strand is modelled as a parallel system of corroded wires. Parametric simulations have been then carried out in order to highlight the effects of the identified parameters, in terms of force-displacement relationship. The objective of this work is to provide an estimation of the corroded strand maximum force under tensile load, which is of great interest from both design and safety assessment points of view.