Because of changing in the diameter of the concrete structure and wall thickness of the Concrete Smokestack Project of Esfahan Steel Mill, implementation of such a special project encountered with challenge. Trusting on the capability of Technical Team of Boozarjomehr Industrial Group, by the application of Slipping Formwork System of the Changeable Section of such structure, the project was implemented.

External diameter of this structure in the lowest point was 5.9 m with the wall thickness of 30 cm, and in the height of 120 m, the smokestack external diameter was 4.7 m and the wall thickness was 25 cm. in consideration of the permanent movement of the Slip form system, the formwork was designed in this manner that, the change in the diameter and wall thickness of the structure was easily made