NASTT is pleased to announce the winners of the 2024 NASTT Outstanding Trenchless Paper Awards for New Installations and Rehabilitation. These awards recognize excellence by commending authors of the best NASTT No-Dig Show papers each year. The winning papers were presented at the NASTT 2024 No-Dig Show.

Download the winning papers or the full conference proceedings featured in the NASTT Trenchless Knowledge Hub.

NASTT 2024 Outstanding Paper – New Installation

Understanding the Importance of HDD Radii

Andrew E. Sparks, PE, Laney Directional Drilling, Highland, Utah
James G. Maingot, Laney Direction Drilling, Corpus Christi, Texas

About the Authors. Drew got his start in geotechnical engineering and likes to spend as much time above ground as underground by hiking, mountain biking, backpacking and canyoneering. Jimmy studied geology with plans to work in the oil and gas industry. A downturn in the job market led to HDD expertise and a career in trenchless technology. Jimmy observed how tooling performed in different situations and how tool wear was different with smaller radii for the same subsurface conditions.  “I also observed how required tolerances are often unachievable as designed,” he said. While Andrew understood the importance of providing an allowable radius to allow an HDD contractor some tolerance when drilling it was not until his discussions with Jimmy that he learned how important the tolerance is to construction and how his designs can make construction easier or more difficult.   That led to both realizing they needed to share their experiences so future HDD designs reduce project risk.

Both credit those they’ve worked with over the years for impacting their career.” I was blessed to learn from many outstanding engineers who shaped my knowledge and experience.  I owe all of them a great debt,” Drew shared.  “I’ve been able to learn more about construction engineering and how engineering decisions affect how a project is constructed- especially in the last six years.  This has made me a better, more thoughtful engineer.” Jimmy executed projects ranging from shore approaches, mountain crossings and other complex crossings. and has worked on more than 500 projects on 6 continents and 24 countries. “I’ve worked with many people who’ve impacted my career over the last 40 years, and I’ve tried to learn from each of them.” Jimmy says thanks. “Those experiences have shaped my career, and I hope that I can share some of that learned knowledge to others. “

Jimmy has spent much of his career traveling overseas, but his favorite place is at home with his family. Both Drew and Jimmy are members of NASTT and especially recommend the education programs and volunteer opportunities stay on top of industry concerns and resources.

Abstract. There are numerous rules of thumb used in the design and construction of HDD installations. One of the most frequently used is the design radius for HDD installations. Whether for steel, HDPE, or FPVC the rule-of-thumb design radius is often used as the final design radius. All too frequently, the design radius is also considered the minimum radius if a minimum allowable radius is not defined in the design. Because design radius affects the tolerances allowed for construction, this could place additional constraints on a project, which increases risk and project costs. In addition, the build rate that a contractor is required to maintain is directly affected by the design radius. If the tolerance window between the lower bound radius and the design radius is small, the contractor will have difficulty installing the pipe within the given tolerances. This paper reviews the purpose behind the rule-of-thumb radius, discusses the several radii used in HDD design and construction, and presents an approach to aid engineers and contractors in selecting appropriate radii and tolerances for HDD projects.

NASTT 2024 Outstanding Paper – Rehabilitation

The CIPP Quality Assurance Paradox

Tony Araujo, Paragon Systems Testing, Concord, ON, Canada
Chris Macey, P. Eng., AECOM, Winnipeg, MB, Canada

About the Authors. Like many, Chris Macey stumbled into trenchless technology early in his career. Tony responded to a phone call from an engineer who needed to test for ASTM D790 flexural properties on an engineering material he had never heard of before. “Those early days servicing the testing needs of CIPP clients were challenging because the properties which we measured didn’t always correspond with the client’s expectations for an installation,” Tony explained.  Where other industries had a more extensive history, Tony relied on curiosity, drive and innovation to find solutions. His competitive spirit stemming from being one of seven siblings may have contributed to his success too.

Years later, both Chris and Tony are looking back and ahead. “While there is so much that has been learnt, there is so much more we can do to extend the envelope as well improve on our ability to build new infrastructure and extend the life of existing infrastructure for the benefit of many generations to follow,” Chris says. Both agreed that the long-term value of testing needs to be known.  “Testing in the world of CIPP is both under-valued and under-used a as means to verify that what we built is what we actually need and intended to build,” Chris explained. “It’s investment related to capital cost investment of the asset we are building (never mind the life cycle cost), is so small and so easy to justify; it is hard to understand why it is so under-utilized.”

Outside of their adventures in testing CIPP materials, both enjoy traveling. Tony and his wife Maria have been exploring their favorite destination, Portugal, with Madeira Island and more parts of the mainland still on their itinerary. Chris and his wife Chrystal have been exploring Italy and learning about its more than 500 different varietals of grapes for making wine.

Both Tony and Chris are active members of NASTT.

Abstract.  Cured-place-pipe (CIPP) has demonstrated that it can be an effective rehabilitation technology when implemented within an appropriately managed project. Numerous specifications have been written to describe the processes which are required to ensure that the Owner is left with rehabilitated assets which will deliver the expected life extension of the asset. The processes included in these specifications typically reflect a balance between, on one side, the risk of a failure to meet design objectives and on the other, the cost, both in direct dollars and indirectly in administration and management, to minimize that risk.

While the first CIPP installation was completed in 1971, the first industry standard practice, ASTM F1216 was not published until 18 years later. Even though the standard has seen regular revisions since then, the recommended inspection practices have largely remained the same even while anecdotal evidence to support more rigorous practices has accumulated. Only very recently has published research based upon actual data from installations demonstrated the prevalence and magnitude of natural variation (lower mechanical properties and/or wall thickness) in CIPP installations.

In this vacuum, the content of owner specifications has come to reflect the individual specification writers experience or lack thereof with CIPP and their perception of the risk of not meeting design objectives. Using statistical and economic analysis of actual project experiences, this paper will demonstrate the risks and costs of a CIPP quality assurance process which has been informed by five decades of research and industry experience.