Select material is important to a successful installation of flexible pipe. HDPE installation procedures recommend that the trench width be established by the designer and ASTM D2321 requires all material in the haunch area be placed by hand. The increased number of joints is a perceived shortcoming of concrete pipe while in fact it may be an advantage. Line and grade is maintained and checked frequently. Various joints and gasket designs are available for most installation conditions from culverts, to storm sewers, to sanitary sewers.
Concrete pipe is available in several different classes and shapes for each diameter.
This gives the designer considerable versatility. By varying the class of pipe, the type of bedding or the installation type, a myriad of designs are available. With concrete pipe, the majority of the pipe-soil structure is delivered to the job site in the pipe. This places most of the burden of performance in the field on the installation method, type of backfill material and adequacy of field inspection. Poor site conditions, such as weak native soils and groundwater, further aggravate the problem.