AN INTEGRATED LIFE-CYCLE RELIABILITY FRAMEWORK FOR STEEL STRUCTURES: CRITICAL REVIEW OF EXISTING AND EMERGING SCIENTIFIC SOLUTIONS

Abstract

Steel structures remain central to industrial buildings, long-span facilities, bridges, towers, transport terminals and rapidly assembled modular systems because they combine high strength-to-weight ratio, fabrication accuracy, reparability and substantial end-of-life recovery potential. Nevertheless, conventional structural design still tends to treat safety verification, corrosion protection, inspection, maintenance, digital monitoring and material reuse as consecutive but weakly connected tasks. This fragmentation creates a methodological gap: a member may satisfy the ultimate and serviceability limit states at the design stage, yet its long-term reliability may decline because deterioration, connection degradation, inspection uncertainty and delayed maintenance are not continuously incorporated into the decision process. The purpose of this article is to critically examine established and emerging scientific solutions in steel construction and to propose an integrated life-cycle reliability framework that connects code-based design, time-dependent deterioration, structural health monitoring, Bayesian model updating, maintenance prioritization and circular use of steel components. The research applies comparative analysis of current design and durability standards, synthesis of recent studies on corrosion reliability, damage identification and digital twins, and an illustrative numerical investigation of three alternative design strategies for a representative steel frame. The proposed framework introduces a unified state vector for section loss, fatigue accumulation, joint stiffness, fire-protection condition and measurement confidence; a time-dependent reliability function; an adaptive intervention trigger; and a life-cycle objective function combining initial cost, expected failure loss, maintenance expenditure, embodied carbon and recoverable value. The illustrative results show that a purely minimum-mass design can be economically attractive at commissioning but becomes inferior when deterioration and uncertainty are included. A durability-enhanced design improves long-term reliability, while the proposed adaptive strategy provides the most balanced outcome by maintaining the target reliability index, reducing expected discounted repair expenditure, limiting unnecessary inspections and increasing recoverability at the end of service life. The scientific contribution lies not in replacing Eurocode, AISC or corrosion-protection requirements, but in organizing them within a closed-loop engineering logic in which design assumptions are verified and updated during operation. This approach supports safer, more economical and more sustainable steel structures, particularly under conditions of incomplete data and variable maintenance resources.