Deflection amount measuring method of the columnar structure, and performance evaluation method of the columnar structure

Deflection amount measuring method of the columnar structures, in the direction parallel to the longitudinal direction on the ground of the columnar structure, on a supporting member for rotatably supporting the cylindrical structure around the longitudinal axis, the columnar structure and placing step of placing, the stillness determination step of determining that the rotation about the axis due to the weight of the placed columnar structures in mounting step is stationary, after the stationary rotation is determined in the still determination step , and a measurement step of measuring a straight line connecting the longitudinal ends of the columnar structures, the vertical distance between the longitudinal curve along the shape of the columnar structure.