Thrust Restraint Analysis of LCP versus ECP Using Non-Linear Finite Element Analysis

PCCP was first manufactured in 1942 as a lined cylinder pipe. The prestressing wire in lined cylinder pipe (LCP) is wrapped directly around the steel cylinder. A second type of PCCP was developed in 1952, in which the steel cylinder was encased in the concrete core, Embedded-cylinder Pipe (ECP). ECP and LCP have different responses to thrust force. The primary thrust restraint methods involve external systems like thrust blocks and anchors. The ability of the pipe to resist thrust is dependent on the external systems and depends on the type of PCCP, whether it is an LCP or ECP pipe. LCP requires more extensive thrust restraint systems compared to ECP. Both LCP and ECP require thrust restraint systems against changes in velocity, pipe expansion, or contraction. The purpose of this study was to evaluate the nonlinear response of LCP and ECP to thrust force. There have been a number of cases where the PCCP pipe failed at bends due to improper analysis of the pipe against thrust force. It is important to understand the mechanical properties of the pipe and the load conditions and be able to perform proper thrust restraint and bending stress in Prestressed Concrete Cylinder Pipes (PCCP). Finite element analysis has been used for modeling and evaluating the behavior of both types of PCCP, LCP, and ECP, against thrust force. The FEA model and results were used to predict and understand the performance of the LCP vs. ECP under thrust forces at bends due to internal pressure changes and flow velocity changes. A comprehensive thrust restraint and bending stress analysis was conducted to compare the response of ECP vs. LCP under thrust forces.