The tunnel under Martwa Wisła in Gdańsk in the first road tunnel in Poland realized with use of TBM method. Its external diameter is 12.2 m. In case of this object it was necessary to use the prefabricated reinforced concrete elements of tunnel casing called tubings. One rign of tunnel under Martwa Wisła consists of 7 segments (6 elements and so called key) and weighs approx. 110 tons, and one tunnel line consists of 537 rings and is 1072.5 m long. The tunnel has two lines of axial spacing of 25.0 m. Each line has road with two lanes. Realization of prefabricated casing elements required great precision, just like concrete placing. Production of tubings consumed almost 47,000 m3 of concrete.
