Andtbacka, Bjorklund, Lofmark, Thorstensson
# 2004 Milan
The performance of buried large diameter structured wall PE pipes has been studied by following the development of the deflection in four different large diameter PE pipes installed in Finland and Sweden. The pipes studied have had an internal diameter of 2000-2400 mm and a ring stiffness of 4-8 kN/m2. Two of the above pipes are road culverts and one a culvert under a railway, all installed in Sweden. The fourth pipe is installed for testing purposes in Finland, exposed to heavy traffic with only 0.6 m of cover on top of the pipe. The ground water table can be read from a stand pipe inside the pipe. The maximum vertical deflection three years after installation has been found less than 4 % for all four installations. Only a very limited increase in deflection has been noted over the years studied. The major part of the deflection (70-90 %) has been achieved during installation and a few weeks thereafter, and after two years the deflection has almost declined. The increase in deflection during the third year after installation was insignificant (<0.2 %) for all pipe installations studied. A varying deflection of up to 7 mm (0.3 %) has been measured at the test installation in Finland, mainly due to temperature variation in the ground.