ABSTRACT
In the composite pipe construction method as defined in the Japan Sewage Works Association’s Design and Construction Guidelines for Sewer Pipe Rehabilitation, a liner pipe is constructed inside an existing sewer and the annular space behind the liner is filled with cementitious grout under pressure to form a highly integrated structure. The Guidelines define a composite pipe as a composite structure requiring complete integration between the renovation layer and the existing pipe. Test results show that the bond strength of cementitious grout is typically half the tensile strength of normal concrete. To fully explore the advantages of the composite pipe method in sewer renovation while keeping safe design in mind, a semi-composite pipe structure has been proposed for structural analysis and renovation design of ageing sewers. This paper focuses on the structural aspect of this design method.
