A sensing system that includes an optical fiber disposed helically around an outer surface of a structure along a longitudinal axis of the structure is provided. The optical fiber is disposed such that at least one complete helical turn of the optical fiber covers the length of the structure. Further, the sensing system also includes a fiber Bragg grating (FBG) set comprising a plurality of FBGs in the optical fiber. Each FBG in the set is configured to generate reflected light that is indicative of strain values at a location of each respective FBG on the optical fiber. Furthermore, the system also includes a processing system coupled to the optical fiber. The processing system is configured to determine location coordinates of each FBG and values of one or more of bending moment, tensile force, and torsional moment acting at each FBG location on the optical fiber.