The efficiency of electricity transmission on overhead transmission lines, in addition to the condition and quality of electrical equipment, depends on the condition of conductors and supporting infrastructure. Towers and cantilevers are exposed to weather conditions and consequently to long-term degradation processes of materials. On-line health monitoring of towers of transmission line poles and their degradation determination is a delicate task. In operation, the tower is expose to mechanical loads due to weathering, but also to changes in tensile forces in conductors due to temperature changes. Actual data on regular and extraordinary mechanical loads of transmission line towers are unknown. Loads due to weathering, wind pressure can be correlate with the accumulation of ice on the conductors and towers. Within the frame of a two EU projects H2020 FLEXITRANSTORE and INTERRFACE, a polygon was designed on several 110 kV poles for which it was necessary to determine the mechanical loads of the towers over a two-year period with on-line continuous monitoring of stress measurements in legs of towers and recording processed results every ten minutes