In the ’70s has been realized many buildings that included large shell of pre stressed concrete with extremely slender sections, the loads were supported by cast arched structures on site made over the cover and connected to the elements by means of steel tie rods.
The weather and the weather conditions tend to deteriorate these structures that after tens of years require renovation works which provide adequate structural reinforcement.
FPT has supplied the hydraulic equipment to perform this consolidation.
The bars used were SAH bars type S670 hot dip galvanized with a nominal diameter of 50 mm and breaking load equal to 1570 kN.
The project included the adoption of the bars such as emergency items in case of collapse of the arch, the implementation required a preload system to perfectly align the bars and remove any coupling play between the individual parts of the system (typically between rods and coupling sleeves as well as in the locking nuts).
It was requested a preload of 70 to 100 kN.
Being the load limited FPT proposed to adopt a double acting hollow cylinder model FPT CRI-30/100-FO with manual pump PDS20DE, with a pressure gauge with full scale of 1000 bar, with an operating pressure high enough to be able to be read correctly (between 166 and 237 bar).
The adoption of a reduction (50 to 32 mm), of a high resistance bar 32 mm in diameter and of a suitable contrast nut has allowed to perform a safe and easy working.
The equipment provided by FPT – Fluid Power Technology is completed by a special hexagon wrench for 80mm operated by tommy bar that has allowed to minimize the size of the saddle.
This project was an example of perfect synergy between design requirements and FPT experience: the technical capacity to serve the customer.