We present a low-power autonomous system for remote structural health monitoring of bridges and similar assets in rural/hard-to-reach areas. The method uses distributed macrobending sections of standard fiber; load-induced loss is measured by optical time-domain reflectometry. The architecture minimizes components and transmits only incremental data via low-power radio or short satellite links, reducing cost and energy use. Laboratory tests detected 0.4 mm displacement; base spatial resolution was ≈1.5 m (0.5 m by interpolation) and dynamic range reached 67 dB. Field trials on a rural reinforced-concrete bridge confirmed autonomous logging of load-induced attenuation. Active-mode power ≤ 2 W enables long-term operation and cost-effective scaling to many sensing points.