Jacking Pressure Pipes as part of Venice’s major environmental plan

The HOBAS CC-GRP Jacking Pressure Pipes that were chosen in 3 m long sections, with an external diameter of 1720 mm and a wall thickness of 85 mm allow a maximal jacking force of 6926 kN. The leak-tight pipe system with its high performance couplings is produced to withstand an operating pressure of 6 to 10 bar. The very smooth outer surface of the pipes enabled comparably low jacking forces and allowed a single jack over the complete section of 351 m. Only the starting and receiving pit were used saving on three originally planned intermediate stations. Thanks to the use of an MTBM (Micro Tunnel Boring Machine) drill head with a hydraulic soil removal (mucking) system and the smooth surface of HOBAS CC-GRP Pipes the line was installed within less than a month. The extremely small roughness coefficient of the inner liner of the pipes and the, compared to other materials, light wall construction reduced the volume of excavated material considerably keeping costs to a minimum and making the installation a complete success.