Mechanical properties of Galfan-coated steel cables at elevated temperatures

Abstract

Investigating the mechanical properties of Galfan-coated steel cables at elevated temperatures is important for the fire-resistant design and fire-simulation analysis of pre-stressed structures. Unlike conventional structural types, Galfan-coated steel cables comprise several steel wires encircling a core wire in different layers. The overall mechanical property of a Galfan-coated steel cable is attributed to the individual properties and collaborative mechanism of Galfan-coated steel wires. The mechanical properties of a Galfan-coated steel cable at elevated temperatures are substantially different from those of conventional structural steel or the single steel wire. In this study, 42 Galfan-coated steel cables with 19, 37, and 61 wires were tested under steady state tension at ambient and elevated temperatures ranging from 100 to 600 °C. The test results show that the cables exhibit typical non-linear characteristics with a lower proportional limit and no clear yield plateau. The reduction factors in the mechanical properties of Galfan-coated steel cables at elevated temperatures are obtained and compared with values predicted in Eurocode 2 part 1–2 and ACI 216, and other studies. Equations for nominal yield strength, elastic modulus, ultimate strength, and ultimate strain for Galfan-coated steel cables at elevated temperatures are proposed in this study. Furthermore, a modified two-stage Ramberg-Osgood model for Galfan-coated steel cables at ambient and elevated temperatures is proposed.