Experimental investigation and predictive model on tensile behavior of corroded high-strength steel and butt-welded connections

Abstract

High-strength steel structures have emerged as an optimal choice for ocean engineering applications, offering enhanced performance, durability and construction efficiency in both coastal infrastructure and offshore installations. However, the aggressive nature of marine environments poses significant challenges to the long-term integrity and safety of these structures due to corrosion. While understanding the degradation of steel material properties is essential, equally critical is the evaluation of welded connections, as joints typically represent critical vulnerabilities in corroded steel structures. This study focuses on experimentally evaluating the residual tensile properties of HG785 high-strength steel and butt-welded connections after exposure to corrosion. Test specimens, comprising both base metal and butt-welded configurations, underwent accelerated deterioration using neutral salt spray exposure, simulating the harsh conditions characteristic of coastal settings. The experimental program incorporated six distinct exposure durations to assess progressive corrosion damage. Surface degradation patterns were precisely documented using 3D laser measurement technology, enabling detailed geometric analysis of the corroded specimens. Through comprehensive tensile testing, the remaining tensile properties of the deteriorated specimens, including load-strain relationships, strength parameters and ductility metrics were evaluated. The findings led to the development of two-stage predictive models that quantify the residual tensile properties of both the corroded HG785 high-strength steel base material and butt-welded connections.