| This thesis presents a finite element model study comparing two-dimensional and three-dimensional buried pipe models. The goal of this study was to analyze the current plane strain modeling used for buried pipe design and a more advanced three-dimensional model and determine the conservatism in the plane strain model. Linear elastic properties were assigned to the soil in the models. A study was developed for the three-dimensional loading models. The pipe soil configurations were varied from unburied pipes to pipes with overburden heights up to 0.75 m. The models were loaded to a specified pipe ring deflection for a two-dimensional line-loaded model and a three-dimensional model. A factor was developed to calculate the ratio of three-dimensional model loads to two-dimensional loads. The ratios were calculated for various loading lengths, different soil depths, E', and pipe wall thickness. Load effect ratios are recommended to modify the loads used in two-dimensional design. |
