IMPROVEMENT OF ESTIMATION FORMULA OF NATURAL PERIOD OF STEEL LATTICE TOWER FOR POWER TRANSMISSION

Although the seismic design of power transmission towers in Japan is not stipulated by law, the design standards on structures for transmissions JEC-5101 published at the end of December 2023 requires seismic design based on the story shear force method. It requires estimation of the natural period to calculate equivalent static seismic load, but the current estimation formula calculates it only from the tower height, and there is a need to improve its accuracy. In this study, the natural period estimation formula that can be applied to steel lattice tower for power transmission is proposed.