TABLE OF CONTENTS The laboratory tests, described in subsection 3.4, are complemented by measurements on a construction site of a pile-supported sewer line in an Alpine valley with very poor soil conditions (Fig. 35). The specific weight of the soil can be assumed as 20 kN/m 3. The pipes are characterized by a length of 6 m, a diameter of 429 mm and a wall thickness varying between 7 and 10 mm. Supported on piles by means of a saddle, which is also made of ductile cast iron, they are placed 4 m below the ground surface (Fig. 2). The groundwater table is located close to the ground surface. During construction the side walls of the pipe trench were secured by sheet piles. The on-site measurements allow to check the assumptions for the loads exerted from the ground on the pile-supported pipeline. Such loading assumptions can be found in recommendations [20] and codes for continuously supported buried pipelines. In addition, the influences of different construction stages were studied in the experimental program. In particular, the changes of the pile forces, caused by removing the sheet piles after refilling the pipe trench and by heavy traffic loading, were measured.
Strain gages were applied for the cross-section of a pipe, directly above the axis of the pile, as well as for the cross-section located midway between both ends of the pipe. The strain gages and the wiring were protected...
