Increases in water demand in growing cities have made the use of large-diameter pipes and fittings inevitable. However, current guidelines and manuals are primarily based on studies performed on regular-diameter pipes, and do not necessary apply to large-diameter pipes. This project seeks to enhance and refine knowledge of the behavior and design of large-diameter flexible pressure pipes using finite element analysis (FEA), specifically in special cases such as large-diameter pipe-valve interaction as a unit system, large fittings, effect of pipe loading on pump nozzles, and transitions from buried concrete structure to soil. The project results will help design engineers, manufacturers, and water utility officers gain insight into these special cases, avoid failures that could be prevented by using FEA, promote a system design approach as opposed to a component design approach, and establish the use of FEA in designing large-diameter flexible pipes. Research partner: Tarrant Regional Water District.