A Comparison of Finite Element Analysis Results with ASCE Manual of Practice 145 Design of Close-Fit Liners for the Rehabilitation of Gravity Pipes

The American Society of Civil Engineers Manual of Practice 145, Design of Close-Fit Liners for Rehab of Gravity Pipes, provides simplified solutions using hand-calculation equations for the design of close-fit structural liners, eliminating the need for more costly soil-structure interaction (SSI) finite element analysis (FEA), particularly for non-circular shapes. This paper presents a direct comparison of MOP 145 results with SSI FEA for a slip-lining installation of a fiber-reinforced polymer (FRP) liner inside an existing deteriorated reinforced concrete three-sided culvert. Using FEA, the host box culvert installation is simulated, the liner is installed, and then the host pipe is fully deteriorated. The liner installation includes placement of fresh (fluid) grout in the host pipe/liner annular space, then modifying the fluid grout to hardened grout. Full degradation of the host pipe is simulated by removing it from the analysis and transferring external loads to the new liner through SSI. The liner demand-to-capacity ratios are calculated using FEA and by equivalent design under MOP 145. This comparison indicates good agreement, validating the use of the MOP for the design of liners.