In this project, in consideration of the large geometrical dimensions of the lining section of such surge ABSORBER RESERVOIRS TUNNELS with the middle span section of 15.2 m and the ceiling to floor height of 14.5 m, and need for coming and going and other operations on the floor of the section, and also, existence of Vertical surge Shaft Absorber with the excavation diameter of 16.4 m under the section of this tunnel, practically, it was not possible to erect the formwork bases on the floor concrete.

Whereas, a similar project was fulfilled by a famous Formwork Making Company in Germany in Mitholz Switzerland, on the basis of erection of the pillar on the concrete floor and blockage of the entire section. Practically, in spite of such a surge absorber shaft under the section, there was no possibility for that method in this project. Therefore, the implementation method proposed by the technical team of BFS Industrial Group in order to overcome such a challenge was to set the formwork pillars on the wings concrete on the height of 8 m (spider- like), and, it is clear that such a design method of the formwork was implemented in Iran for the first time, and as the opening and closing system of formwork is full- hydraulic, and as the formwork is self- propelled, and because of removal of challenge of existence of the shock absorber shaft of the floor of bottom of the section and making the chassis pillars of the formwork independence from the floor concrete, the efficiency of the lining operations and the speed of this project were increased.