Evaluation of the Structural Performance of Epoxy Linings for Manhole Rehabilitation Using Laboratory Testing and FEM Simulations

Large amount of sewer manholes in the United States are facing serious structural decays and are in need of immediate rehabilitation. Among various candidate techniques, spray-on lining is one of the promising techniques for no-dig manhole rehabilitation. Based on a new manhole rehabilitation classification system proposed by the authors, epoxy lining is considered as semistructural material and relies on residual strength of existing manhole structure to withstand external loads. Prediction of structural capacity of epoxy-lined manhole structure is a challenging task as the mechanism of epoxy lining reinforcement is not clearly understood. In this study, first laboratory tests on concrete cylinders and beams lined with epoxy lining were performed to evaluate structural performance of concrete with epoxy lining. The laboratory testing provided measurements of basic mechanical properties of concrete and epoxy. However, the lined manhole structures in the field conditions cannot be accurately represented by laboratory testing. Finite element modeling (FEM) using ABAQUS software was used to simulate epoxy-lined concrete members in the field loading conditions. Computer simulation is able to analyze how structural capacity of epoxy-lined manhole is affected by mechanical properties of epoxy, such as flexural strength, elongation, adhesion, and thickness. Results show that FEM simulation can be used to analyze, predict performance, and design epoxy lining for deteriorated manhole rehabilitation.