Project Updates

Experimental Evaluation of Starline 2000TM: Mechanical Properties of Curable Adhesives and Service Life Assessment under External Loading

Vishakha Gautam — Wed, 01 Apr 2026 03:00:52 +0000

Experimental Evaluation of Starline 2000TM: Mechanical Properties of Curable Adhesives and Service Life Assessment under External Loading Vishakha Gautam Tue, 03/31/2026 - 21:00

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.

Full-scale specimen in frame with four-point bending configuration

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.

Peel test setup with modified floating roller peel drum test

Cured-in-Place Lining System

Project Team

Sina G. Senji

Brad Parker Wham

This Project emphasis is about enabling confident, performance-based decisions for pipelines rehabilitation using trenchless technologies.

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Seismic Performance Assessment of iPVC Pipeline Systems: Bend Fittings and 6 in. Diameter Pipe (Underground Structural Research)

Vishakha Gautam — Wed, 01 Apr 2026 02:32:13 +0000

Seismic Performance Assessment of iPVC Pipeline Systems: Bend Fittings and 6 in. Diameter Pipe (Underground Structural Research) Vishakha Gautam Tue, 03/31/2026 - 20:32

Problems to solve

Evaluate the Seismic Performance of iPVC Pipeline Systems with reinforced gaskets under extreme environments such as earthquake, PPI Pipe America Inc.

Approach

This study was conducted for PPI Pipe America Inc. and presents test results from a program to investigate the test performance of nominal 6-in. (150-mm) diameter polyvinyl chloride (iPVC) pipe and joints with reinforced gaskets. Tensile coupon tests were performed to characterize the fundamental stress–strain behavior of the iPVC material. Numerical modeling (1-D beam system and 3-D component-level simulations) was conducted to interpret leakage onset and material failure under large deformation.

Results

Preliminary results show robust tensile and cyclic performance of iPVC pipe joints and couplings. Consistent deformation behavior across different coupling configurations (Straight, Tee, 45°).No significant leakage or coupling disengagement was observed under the tested displacement ranges. Numerical results are being used to validate experimental response and failure mechanisms

Implications

Provides critical data for developing seismic design criteria for iPVC pipelines in areas susceptible to fault rupture and lateral spreading. Strengthens understanding of reinforced gasket and coupling behavior under combined loading. Supports advancement of the ASCE STEPS framework and pipeline performance standards. Demonstrates effective collaboration among academia, utilities, and industry

Figures show the pretest and loading process for straight coupling. Thanks to live observation during the test, we have an opportunity to assess of serviceability of specimens.

Five vertical string pots were used to measure bending displacements along the length of the pipe and are shown in the left Figure. These string pots were placed on the centerline, and at 16in (406 mm) and 22.5in (571 mm) on both sides. Displacements on each side of the coupling were symmetrical, showing even bending deformation along the pipe

Project Team

Brad Parker Wham

Muhammet Ceylan

Joshua Tan

Industrial Collaborations

Evaluate the Seismic Performance of iPVC Pipeline Systems with reinforced gaskets under extreme environments such as earthquake, PPI Pipe America Inc.

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Denver Water Meter Lid Testing

Vishakha Gautam — Wed, 01 Apr 2026 01:43:34 +0000

Denver Water Meter Lid Testing Vishakha Gautam Tue, 03/31/2026 - 19:43

CIEST tested two composite meter lids by two different manufacturers to a proof load of 40 kips to determine if this new material was an effective replacement for traditional cast iron lids. These tests were conducted according to standard AASHTO M 306-10. One composite meter lid was manufactured by EJ Durostreet and the other was manufactured by Trumbull. One cast iron lid was used as a reference, from Copeland Precast.

Cast iron meter lids are currently the industry standard, and the default material used for the vast majority of water meters. The main downside of traditional cast iron water meter lid is that it is very heavy, demanding more resources for handling thus it often poses a work-related safety hazard. Fiber reinforced composite meter lids offer a lighter alternative. The behavior of these composite meter lids is, however, much less studied than that of the traditional cast iron lids.

The standard specifies that a proof load of 40 kips (178 kN) must be applied to the lid via a 9”x9” area. Upon reaching this load, the position of the actuator should be held for one minute and then released. After the 40-kip proof load was applied, the lids were visually inspected for any permanent deformation, cracking, or other defects. Per Denver Water’s request, upon the meter lids had successfully passed the requirement set by the standard, the lids were then further tested to failure or up to 70 kips, whichever came first.

The loading rates were calculated based on an initial stiffness test of each material, aiming for 500 lb/s as the standard specified the loading rate must be between 100 and 1000 lb/s. The Durostreet lid reached the target load of up to 70kips (exactly 72.1 kips), however the Trumbull lid could not be tested beyond 60 kips due to deformation and cracks developed, which tilted the horizontal load balance. The cast iron lid was tested up to 70 kips and rendered direct comparison against two composite lids.

The Durostreet and Trumbull lids proved to be more elastic than the traditional cast iron lid. The Durostreet lid was tested to 72.1 kips and did not exhibit permanent deformation as the LVDT returned to its initial position exactly. All three lids passed the proof load test as they were not visually observed to have any cracking, permanent deformation or other defects after applying the 40-kip load, and as specified in the standard, the recorded permanent deformations were not greater than 1/8” (0.125”) after applying the 40 kip load. The Trumbull lid showed deformation and cracks around 60 kips, yet it did pass 40kips without visible defects under the testing standard.

CIEST tested two composite meter lids by two different manufacturers to a proof load of 40 kips to determine if this new material was an effective replacement for traditional cast iron lids.

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