Fig. 1. Sensing principle of the FBG

Fig. 2. Structure of self-sensing steel strand. (a) Physical drawings; (b) schematic diagram

Fig. 3. Damage location distribution of common steel strands. (a) Damage location diagram of each set of steel strand; (b) damage area of single strand of B₁₁ steel strand 2/3

Fig. 4. Distribution of steel strands in the anchorage plate

Fig. 5. Physical drawing of the pretest tensioning machine

Fig. 6. Overall picture of steel strand after wire breaking

Fig. 7. Changes of broken wire signal of the first group of specimens in loading process. (a) B₁₁; (b) D₁₂; (c) D₂₂

Fig. 8. Changes of broken wire signals of the second group of specimens in loading process. (a) B₁₁; (b) D₁₂; (c) D₂₂

Fig. 9. Changes of broken wire signal of the third group of specimens in loading process. (a) B₁₁; (b) D₁₂; (c) D₂₂