Buried assets: Out of sight but not out of mind

Three-dimensional model of underground infrastructure

When most people see UI, they think user interface. However, it also stands for underground infrastructure — or what is commonly known in the field as buried assets. These underground lines are truly lifelines, providing the essentials of modern human life, such as water, energy, transportation and telecommunications. Yet they’ve been neglected; according to the American Society of Civil Engineers (ASCE) in its 2021 Report Card, U.S. infrastructure gets an overall grade of C-, and some categories of UI generally receive a D grade.

Improving these scores will require using the world’s most advanced underground solutions. We need to develop more reliable inspection and analysis techniques. And we need to enhance and leverage new technologies, such as digital twin, augmented reality (AR) and virtual reality (VR), to more effectively manage our underground infrastructure.

Humankind has always been interested in the space underneath its feet. In ancient times, the underground was often thought of as a place to go after death. Some say Neanderthals developed underground space, and remains of ruins have been found. Others claim that underground space was exploited as people dug into the earth to mine metals.

In earliest days, humans developed underground space by digging into the soil by hand and with tools and livestock. This “open-cut” method was supplanted by gunpowder, first used in underground construction in France in 1681. The invention of dynamite, and steam and compressed-air power drills, in the 18th century further revolutionized the industry. The 19th century saw innovations in shield tunneling (using temporary, protective support structures during excavation), which made underground construction safer. In the 20th and 21st centuries, construction techniques have centered around tunnel-boring machines, trenchless technology (minimal open and continuous trenches), and shotcrete (concrete sprayed through a hose).

With much of Earth now covered with buildings, underground space has become crucial. Instead of augmenting this terrestrial area, the new frontiers that humankind can use in the future are said to be underground, ocean and extraterrestrial space. But it’s difficult to access these spaces — other than going underground — due to technical limitations. Therefore, people are putting a lot of effort into developing underground space.

Advantages of these undertakings are multiple. Dense urban environments lack sufficient aboveground infrastructure for transit and for distribution of goods, resources and services. These shortcomings can lead to traffic congestion; poor environmental conditions, due to noise and air pollution; insufficient protection against natural disasters like flooding; crowding; lack of space for work and recreation; and building restrictions, due to preservation efforts around aesthetics and heritage.

With America’s underground infrastructure in poor physical condition, and potentially unable to meet current and future demands, there is a need for more efficient and accurate methods to evaluate existing conditions. New technologies related to the 4th Industrial Revolution, such as the Internet of Things (IoT), are being developed and applied to this field. For example, artificial intelligence (AI) is being investigated to analyze a range of big data collected using sensors.

In addition, construction technology is advancing. Take microtunneling — the only practical method for small-diameter pipeline construction in variable and unstable stratigraphic (rock-layer) conditions. Microtunneling not only allows for installation of new pipe but also can be combined with replacement methods to swap out aging pipe. Our Underground Infrastructure Team (UIT), part of the Division of Construction Engineering and Management (CEM) at Purdue, is working with experts in Colombia and a Japanese equipment company to develop a system that replaces pipe without leaving any asbestos cement particles from the original pipe.

QuakeWrap’s FRP technology was applied to the Lake Lure Dam penstock rehabilitation project in North Carolina, extending the life of the penstock by 50 years. Purdue Engineering’s Tom Iseley (in the orange hard hat) and Wei Liao participated in the second warranty inspection on Jan. 6, 2022. (Purdue University photo/Wei Liao)

UIT also is pursuing many additional innovative avenues. We are developing a more accurate methodology to assess the current status, and calculate the lifespan, of water and sewer pipelines, using condition-evaluation data and recorded videos. Our approach will be used to help standardize people’s water consumption patterns and detect leaks in water distribution networks. In addition, we’re working to create more reliable sewer pipe and tunnel inspection and analysis techniques, leveraging a patent held by CEM Professor Tom Iseley for a sewer- pipe-sidewall scanning system.

Another UIT project involves creating an automated video interpretation system to consistently, accurately and quickly assess tunnel conditions by minimizing manual inspection errors. This work can significantly improve inspection productivity, and provide a platform for developing autonomous inspection systems in the future.

UIT also has a strong educational component. Our team members are teaching Purdue courses including Asset Management for Buried Pipe, Construction Business Management, and Development of Underground Space. Our main mission is to advance the underground infrastructure industry, and expand Purdue’s presence in underground engineering and construction, in order to encourage more of the younger generation to get involved.

In addition, UIT will work with Princeton University professor Ed Zschau to launch a new High-Tech Entrepreneurship course within the College of Engineering in Fall 2022. It is based on prior versions that have been offered a total of 40 times in engineering schools at Princeton, Caltech, and University of Nevada, Reno for more than 1,800 students during the past 25 years. The course embodies learning by doing. Our approach to interacting with students and encouraging their thoughts about entrepreneurship and their own lives is meant to help them understand that life is not a “spectator sport.” We hope the students can shape the paths available to them, and choose to follow whichever paths they decide might be best for them.

Additionally, we actively collaborate with the Buried Asset Management Institute — International (BAMI-I), a nonprofit corporation whose purpose is to educate and assist those interested in applying best buried asset management practices to extend the life and efficiency of their assets. Professor Iseley has served as chairman of the institute since its founding, and Wei Liao, CEM lead research engineer, serves on the board of directors and edits the BAMI-I Journal.

Ability to understand and extend the life cycle and efficiency of buried assets is critical in preventing us from repeating mistakes and overlooking infrastructure deterioration. Government is stepping in to help ensure this outcome — witness Bill SB 272, related to asset management and technical training, signed by Indiana Gov. Eric Holcomb on March 7, 2022. This bill states that as part of any financial assistance package, infrastructure firms must submit information on estimated and actual life cycle management costs over the useful life of the asset financed.

Continuous investment is needed to ensure that underground infrastructure performs its role of delivering essential services with an increased resilience to handle whatever comes its way. More R&D support is crucial, in technologies like digital twin, AR, and VR. Addressing these challenges will require state-of-the-art research institutions and their teams to implement user-inspired basic research, taking an interdisciplinary approach to innovate engineering technologies and equipment that the industry so desperately needs. We also have to cultivate a diverse workforce, to meet the challenges of labor shortages.

Achieving these enhancements will take a high level of industry involvement in identifying research issues that prioritize industry necessities. We need to secure the resources of research capabilities (talent, facilities, and time commitment) of universities that are at the forefront of specific research areas. Establishing industry-university cooperative research and training centers is vital. And we need government encouragement and funding to coordinate these efforts.

Wei Liao, PWAM

Lead Research Engineer

Division of Construction Engineering and Management

College of Engineering, Purdue University

Tom Iseley, PhD, PE, Dist.M.ASCE, PWAM

Beavers Heavy Construction Distinguished Fellow

Professor of Engineering Practice

Division of Construction Engineering and Management

College of Engineering, Purdue University

Chair, BAMI-I Board of Directors

President, International Infrastructure Solutions, LLC

Saleh Behbahani

PhD Student

Division of Construction Engineering and Management

College of Engineering, Purdue University

Kibum Kim, PhD

Visiting Scholar

Division of Construction Engineering and Management

College of Engineering, Purdue University

KwangHyuk Im

PhD Candidate

Division of Construction Engineering and Management

College of Engineering, Purdue University



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