A high-fidelity computational investigation of buried concrete sewer pipes exposed to truckloads and corrosion deterioration. (15th October 2020) - Zamanian, Soroush
Highlights: High-fidelity 3D-FE models of common buried concrete sewer pipes are developed. The models accurately and efficiently capture leakage vulnerability of pipes. Impacts of degradation are considered over the service life of sewer pipes. The time to leakage is sensitive to models chosen for soil and soil-pipe interaction. Leakage occurrence is affected by installation types for the case of fine-grain soils. Abstract: As wastewater systems are reaching critical levels of aging and deterioration, simulation of realistic pipe behaviors is ever more needed to analyze and manage the associated risks. Developing such models is challenging, in part due to the complexity of aging and deterioration impacts on the structural and functional performance of pipes. This study investigates the impacts of a number of design and uncertain variables on the serviceability performance of concrete sewer pipes throughout their service life. This is facilitated by a high-fidelity three-dimensional Finite Element (FE) model of concrete sewer pipes, surrounding soil, and pavement layers in ANSYS platform. The FE model is capable of capturing nonlinear behaviors of concrete, soil, and pipe-soil interactions, in addition to simulating crack formation and crushing of concrete pipes. Corrosion impacts are simulated by sequentially removing concrete layers inside the pipe so that corrosion effects from previous years are taken into account. The influence of linear versus nonlinear assumptions for soil and pipe-soil interactions on the performance of the pipes especially crack width are investigated for cases where the models are subjected to external truckloads. Moreover, impacts of most common trench installations in terms of bedding, side-fill configuration, and soil properties are analyzed for the entire service life of the pipe. Results reveal that the soil surrounding the pipe needs to be modeled as a nonlinear material regardless of the soil grain size. It was observed that the error associated with modeling soil and soil-pipe interactions as linear increases as the pipe ages and the extent of corrosion increases. Results of this investigation can guide the development of reliable and computationally efficient numerical models for deteriorating underground concrete sewer pipes.