Performance-based Decisions for Pipelines Rehabilitation

This Project emphasis is about enabling confident, performance-based decisions for pipelines rehabilitation using trenchless technologies. Utilities and regulators need to know not only that a liner can be installed, but that the rehabilitated system can tolerate decades of cyclic loading and occasional extreme deformation events without loss of function. By developing repeatable laboratory methods that map realistic field actions (traffic, excavation-induced ground movement, and thermal effects) into controlled test demands, the project supports safer, less disruptive rehabilitation strategies. This outcome helps to extend the life of critical energy infrastructure while reducing community impacts from construction. The work was funded by DOT/PHMSA and carried out at the Center for Infrastructure, Energy, and Space Testing (CIEST) at the University of Colorado Boulder, with project partners including Progressive Pipeline Management (PPM). 

Project Description:

Across North America, many legacy metallic gas mains are approaching (or exceeding) their intended service life, and traditional open-cut replacement can be expensive, slow, and highly disruptive. Trenchless rehabilitation methods can reduce excavation and environmental impacts and can be cost-competitive by renewing the inside of the host pipe rather than replacing the entire line. Yet, despite widespread use and the existence of standards and guidance documents, key questions remain about long-term suitability, how rehabilitated systems respond to external loads, and how adhesion between liner and host pipe influences structural capacity and performance over time.

A central motivation for this work is that real pipelines do not experience only internal pressure; they also experience demanding external actions throughout their lives. The project highlights four dominant external drivers that can govern performance in the field: (1) repeated surface traffic loading, (2) ground movement associated with adjacent excavations, and (3) thermally induced axial deformation (4) Ultimate tensile strength. The framework therefore advances a lab-based approach that reproduces these field-relevant deformation demands in a controlled environment so that rehabilitation technologies can be assessed against realistic, service-life-type conditions rather than only short-duration, idealized tests.

The work uses CIPL system with an established history in laboratory and field applications, as a representative repair technology, while extending prior research foundations to reflect today’s materials and performance expectations. The project follows emerging standardization, including a soon-to-be-released external loading test method for IRP systems. The project includes a comprehensive set of standardized coupon-level tests to characterize the mechanical properties and durability-relevant attributes of curable adhesives (e.g., tension, compression, flexure, chemical resistance, peel, lap shear, and hardness) as inputs to engineering decisions and broader qualification pathways.