ABSTRACT
Most sewers are constructed underground. This is achieved by one of three general methods: open-trench construction, tunnelling, and trenchless construction. This chapter describes these three methods of construction. It considers physical aspects of sewer pipes and their design. Pipelines must possess a number of physical properties. They must also give satisfactory performance hydraulically and structurally. The chapter also considers important issue of structural performance. It provides a discussion on site investigation and introduces issues surrounding costs and carbon accounting. Site investigation identifies problems with ground conditions and special hazards that may have a significant effect on planning, choice of pipe material, structural design, and construction. Site investigation is of great importance for all types of sewer construction but may have particular significance for schemes involving construction of sewers in tunnel. Along with understanding the financial cost of capital options and maintenance strategies, it is commonplace to estimate the embodied and operational carbon of a scheme.
