Project Title: Evaluation of Gate Valve Flanges: Serrated vs Non-Serrated Under External Loading

Industry Partners: Denver Water

CIEST Personnel: Cory Ihnotic and Jessica Ramos

Primary Investigator: Prof. Brad Wham

Year: 2024

The intent of this study is to investigate the difference between a serrated faced flange connection and a non-serrated faced flange connection; mainly to determine whether one would leak sooner than the other. To evaluate this, a series of four-point bending tests with applied axial load were conducted on Mueller Resilient Wedge Gate Valves. The tested specimens were commercially available 6 in. (150 mm) diameter ductile iron pipe conforming to AWWA C600 standards, which were provided by Denver Water. Each type of flange connection (serrated or non-serrated) received two tests, each with displacement applied at a rate of 1 in. (25 mm) per minute. For the conducted tests, several points of interest were located including the site of the first and second leaks, and their respective leak rates to determine which of the connections had a more substantial failure.

Appreciation is extended to John Daly and Katie Ross, along with all our pipe and coupling manufacturers, for their tremendous support.

Testing Report 

Link to testing report: /center/ciest/sites/default/files/2025-03/240820%20DW-Serrated%20vs%20Nonserrated__Final%20Draft_v2.pdf

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Project Title: Performance Assessment of iPVC Pipe and Coupling for Large Ground Movement 

Industry Partners: East Bay Municipal Utility District, Denver Water 

CIEST Personnel: Nicholas Berty, Cory Ihnotic, Katherine O’Dell, Jessica Ramos

Primary Investigator: Prof. Brad Wham 

Year: 2022 

Project Summary: The intent of this study is to define the seismic response of iPVC pipeline systems with couplings and to illustrate procedures for interpreting laboratory results to seismically classify pipeline system performance following developing ASCE seismic guidelines. Twenty large-scale tests were performed on 6-in. diameter DR14 (PC305) iPVC pipe (C900) with five different commercially available reinforced connections. Test specimens were subjected to tension, compression, cyclic, and four point bending tests, determining the ultimate load capacity for each system in both axial and transverse directions. This study provides the first seismic classification for plastic pipe systems with reinforced connections. 

Appreciation is extended to David Katzev and Katie Ross, along with all our pipe and coupling manufacturers, for their tremendous support. 

Link to Report

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Project Title: Hoop Tensile Test

Industry Partner: PSI Lab

CIEST Personnel Participants: John Hindman

Year: 2022

Project Summary:

The CIEST Laboratory successfully completed testing pipe liner samples for “apparent hoop tensile strength” as described in ASTM D2290. The method uses a split disk to apply tensile forces to a hoop or ring specimen cut from a pipe. Like a standard tensile test specimen, the hoop specimen also has an area of reduced width so that the failure should occur in a desired location. Load is applied at a constant rate of travel until a break occurs. The strength of the specimen is calculated based on the force at break and the cross-sectional area of the reduced area.

The test was performed on one of the CIEST Laboratory’s hydraulic-actuated test frames. We were glad to be able to perform these tests for an independent commercial laboratory. The size and strength of the particular samples tested required the use of a larger test machine, which we were able to provide. 

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Project Title:  Seismic Evaluation of Hazard-Resistant Lifelines: Fusible PVC Pipe and Fittings

Industry Partners: Aegion Corportation - Underground Solutions Inc. 

CIEST Personnel: Cory Ihnotic,  Jessica Ramos, D.K Anderson, David Balcells

Primary Investigator: Prof. Brad Wham 

Year: 2021

Project Summary: The intent of this study is to impose external loading conditions to test specimens that are representative of the significant deformations possible during earthquake-induced ground motions such as landsliding, fault rupture, and liquefaction-induced lateral spreading, characterizing the pipeline system capacity. This testing program seeks to define the seismic response of fusible PVC (fPVC) pipeline systems with both fused connections and external couplings, illustrating procedures and best practices for conducting full-scale tests and interpreting laboratory results. Thirteen large-scale tests were performed on 6-in. diameter DR18 (PC235) fusible PVC pipe (C900) with three different connection types. Test specimens were subjected to tension, compression, cyclic, and four point bending tests, determining the ultimate load capacity for each system in both axial and transverse directions. 

Link to report: /center/ciest/sites/default/files/attached-files/240724_ciest-ugs_fusible_report_to_be_published.pdf

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Full Project Title: Axial Capacity of C900 PVC Pipe with Reinforced Gasketed Joints

Year: 2019-20

Industry Partner: Denver Water

CIEST Personnel: Jessica Ramos, John Hindman, Brice Lucero, David Ballcells, Hayley Parnell, and Porter Hawkins

Primary Investigator: Prof. Brad Wham

Summary: The objective of this study was to impose externally applied axial loading to reinforced gasketed water pipeline joints to establish upper bound performance under worst case conditions of ground movement.  Test protocols included axial tension and cyclic (progressive tension and compression) loading on bell-spigot style C900 PVC pipe to simulate deformations possible during natural hazards such as earthquakes and landslides . The test specimens consisted of either RieberLok Gasketed or Diamond Lok-21 pipe with a restraining ring. Tests provided measures of axial displacement capacity, pipeline connection strength, and failure mechanism. The results indicated these systems as potentially viable solutions for regions prone to persistent soil movement and settlement. Tests were conducted in partnership with Denver Water.

Failed specimen after testing in tension.

View the full report here.

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Project Title: Tension Testing of Flexible Expansion Joints  

Industry Partners: EBAA Iron, Inc. 

CIEST Personnel: Hailey Parnell, Lindsay Guerrero, Bruce Lucero

Primary Investigator: Prof. Brad Wham 

Year: 2020 

Project Summary:  The intent of the test program is to investigate the axial performance of a Flex-Tend Flexible Expansion Joint (FEJ) and a Force-Balanced FlexTend Flexible Expansion Joint (FBFEJ), each nominally 6-in. diameter. Externally applied axial tension load test results are compared to data obtained from internal pressure burst tests and demonstrate that, while similar levels of axial force are required to initiate component failure, the failure mechanisms differ and and influenced by the circumferential stress supplied during burst testing. The work was undertaken in the Center for Infrastructure, Energy, and Space Testing (CIEST) which is affiliated with the Civil, Environmental, and Architectural Engineering Department at the �鶹��Ƶ.  

Follow this link for the Report by H.L. Parnell, L. Guerrero, B.A. Lucero, and B.P. Wham.

Testing Report

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Full Project Title: Seismic Evaluation of Hazard-Resistant Pipelines: Axial Testing of PVC, PVCO, and iPVC Pipe with Coupling

Year: 2019

Industry Partners: East Bay Municipal Utility Department (EBMUD)

CIEST Personnel: Cory Ihnotic, David Kyle Anderson, Jessica Ramos, David Balcells, Brice Lucero, John Hindman, and co.

Primary Investigator: Prof. Brad Wham

Summary: The first in a series of testing programs at CU Boulder CIEST investigating performance of critical lifeline systems under extreme loading conditions. This study focuses on the response of various thermoplastic pipe materials and a coupling connection under externally applied axial and lateral loading.  Internally pressurized, 6 in. (150 mm) diameter specimens were tested to failure under various loading scenarios including axial tension, compression, and cyclic loading as well as transverse 4-pt bending. This project initiated the development of self-reacting test frame capable of applying dynamic tension and/or compressive loading in excess of 100,000 lbs (445 kN) to linear structures up to 12 ft (3.66 m) long. CIEST’s 1,000,000 lb (4450 kN) four-post load frame was employed to apply lateral loading.  

View the full report

Appreciation is extended to collaborators David Katzev and Timothy Harris of EBMUD for their intellectual and practical contributions to the project. 

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