Grant: Discovery Grants Program - Individual

Evolving urbanization and deterioration of old sewer and water supply infrastructure have greatly increased public expenditures on repair and replacement (>$1B/yr in Ontario). Most research on buried pipes has worked to address bending and buckling around the pipe circumference, considering the pipe in its initial burial configuration over the full service life. However, other factors also influence failure mechanisms and service lives, and these require investigation: 1.Pipe failures often result from backfill deterioration as water inflow through joints or corrosion voids erodes the surrounding soil support and increases moments, and new methods are needed to analyze and understand backfill erosion and its impact; 2.Thermoplastic pipes (e.g. polyethylene) are held in position by backfill. Fracture mechanisms for gravity flow pipe are different to those induced by current pressure tests, given the influence of relaxation & bending, and service lives for fixed strain and bending need investigation; 3.Work is needed to resolve a number of issues associated with trenchless construction (ground movements during pipe bursting and directional drilling, and design methods for pressure pipe liners); 4.Cast iron and asbestos water pipes usually experience ring fracture as a result of differential ground movements, and the effects of frost or moisture changes in reactive soils need study. 5.The mechanics of phenomena like uplift buckling and bending where pipes span zones of earth movement down slopes also need to be studied. Fourteen different projects in three theme areas are being proposed over the next five years of DG funding. Five MASc and nine PhD students will work on projects obtaining seminal test results, developing new methods of computer analysis, and producing new or improved procedures for pipe and culvert installation, assessment, and design.