Manufacturing of fiber Bragg grating smart steel strand finished cables

Purpose This study aims to develop a sensing-integrated finished cable by embedding fiber Bragg grating (FBG) strain sensors in a steel strand and to verify sensor survivability plus anchorage/load-bearing performance under static tension. Design/methodology/approach Five FBG sensors were embedded in a longitudinal groove of the strand’s central wire. Three finished-cable specimens were fabricated using an anchor cup and cold-cast filler. Static tensile tests were conducted following GBT14370-2015, and strains were monitored in the anchorage zone and the middle free section to evaluate calibration performance, monitoring range, anchorage efficiency and ultimate capacity. Findings All sensors survived loading (100% survival). Calibration showed strong linearity with a correlation coefficient exceeding 99.657%. Effective monitoring was maintained up to 80% of ultimate capacity; data anomalies at 95% load were excluded, and the monitoring range was concluded as 0%–90%. The finished cable achieved an average ultimate capacity of 821 kN versus a theoretical 790 kN, with anchorage efficiency coefficients of 1.013, 1.069 and 1.077 (>0.95). Anchorage-zone strain presented three stages (<80% gradual rise; 80–90% reduced growth due to slip; >90% sharp rise with cold-cast cracking). Research limitations/implications Only three short specimens and static tests were used. Future work should assess fatigue, corrosion/temperature effects and full-scale field deployment. Results support the feasibility of embedded-FBG monitoring without degrading capacity. Practical implications The cable can be installed like a conventional prestressing tendon while providing real-time force/strain monitoring, including within the anchorage zone, reducing labor-intensive field measurements. Social implications More reliable cable monitoring supports early warning for bridges and cable-supported buildings, reducing the risk of sudden failures and service interruptions. Originality/value The work couples multi-point embedded FBG sensing with a finished multi-strand cable and experimentally validates both sensing reliability and anchorage/ultimate capacity in one program.