Reducing infrastructure project costs and timeframes
Cities are on the brink of the largest infrastructure investment wave in history, but infrastructure projects routinely go over budget and deadlines. Subsurface utility risks are a major cause of these costs blow-outs, but these risks could be mitigated if cities and design engineers undertook proactive mapping of their subsurface environment. While an expensive upfront cost, multiple studies show major positive return-on-investment figures from this proactive investigation, and yields major cost, time and labour savings over the construction span of the project.
The largest infrastructure investment wave in history
Population growth and urbanisation are projected to add 2.5 billion people to the world’s urban population by 2050. The expected increase in urban land cover over the next 30 years will be faster and larger than any previous urbanisation trend in history.
To support this massive influx of urban dwellers, cities worldwide are gearing up for a new wave of infrastructure spending to provide housing, transportation, and services to the growing population.
The US Infrastructure Investment and Jobs Act 2021 includes $1.2 trillion in spending to rebuild roads and bridges, maintain water infrastructure, and expand access to high-speed internet in rural areas. This sum represents only a five-year commitment to address critical infrastructure deficits, in the United States alone. The global infrastructure deficit figure is estimated at $15 trillion by 2040.
Rising population meets resource constraints
The surge in infrastructure spending comes with constraints. Cities account for 70% of global carbon emissions. Countries that have signed up to global emissions treaties must balance construction activity against carbon emissions targets that are massively affected by materials (particularly concrete and steel production).
And if that wasn’t enough, cities do not operate in a greenfield environment. Existing legacy infrastructure needs replacement or upgrading, and the threat of rising sea levels make disaster resiliency yet another item to add to the long list of commitments for public spending.
The international economic environment has provided a rosy couple of decades with low interest rates, growing working-age populations, and productivity gains from technology creating positive conditions for megaprojects.
But these fundamental factors are changing – interest rates are rising, the ageing population in Western countries is hampering industries in need of skilled workers, and despite fast-evolving technology gains, the cost and timeframes of infrastructure are spiralling out of control.
Infrastructure costs and timeframes are blowing out
Across the Western world, it has become routine for infrastructure projects to go overbudget and years past deadline.
Crossrail, the London underground rail extension, is already two years behind schedule and £4 billion over budget, while Toronto’s York-Spadina subway extension was completed ten years late and over CAD$1 billion over budget.
These are not isolated examples. A study from the University of Toronto that looked at 258 major road, tunnel, bridge, transit and rail projects in 20 countries on five continents found that 90% of these projects went over budget.
Timeframe overruns go together with cost overruns. Planning variations, compliance costs and increased consultation with communities all push timeframes further into the red, with increased costs from penalties and overtime, not to mention disruption to ratepayers and businesses.
Effects of exploding budgets
The consequences of these exploding costs include government budget deficits and a loss of public confidence that government can meet its public commitments:
“Poorly executed public works can burden governments with hundreds of millions of dollars in unexpected expenses, put the financial viability of projects at risk, and exacerbate construction-related disruptions for residents and businesses. Persistent project delivery problems also jeopardize public confidence in the ability of government to deliver complex but critically important infrastructure projects. As public trust is eroded, it can become harder to build support for the next generation of critical municipal infrastructure investments.” author Matti Siemiatycki, Cost Overruns on Infrastructure Projects: Patterns, Causes, and Cures.
Subsurface risks are a leading cause of cost overruns
The area below ground, typically 0-7m below the surface where crucial utilities such as power, gas, water, and telecommunications cables are located, is known as the subsurface. Nearly all infrastructure projects involve subsurface excavation and installation or relocation of utilities.
As with many of our other natural resources, the subsurface has been exploited and overburdened as cities intensify their resource usage, and new services such as high-speed broadband are brought online. Greater electrification and retiring of gas pipeline infrastructure will involve even more disruption of the underground, and innovations such as The Boring Company’s personal transport tunnels put even more demands on this scarce real estate.
Our knowledge of the subsurface is incomplete, inaccurate, and inadequate. Records of existing utilities are often incorrect or out of date, and no city has a complete overview of its subsurface assets or risks. In the United Kingdom, The Ordnance Survey has suggested that “£5.5billion is spent every year on exploratory excavation just to figure out what’s underground.”
When it comes to construction, excavation works are frequently delayed by the discovery of “unknown” utilities that conflict with designs. As a result, contractors and designers will routinely add 10-30% to a project’s costs to cover unknown subsurface risks.
An ongoing infrastructure project in Wellington shows how the issues with lack of subsurface info and planning contribute to major delays and cost escalation.
Case Study: Petone/Melling Cycleway
Just north of Wellington city, New Zealand, local authorities planned to construct a new cycleway between the suburbs of Petone and Melling in Lower Hutt. The project incorporated a 3.5m wide cycle and walking path with two underpasses in between state highway and main rail corridor.
This project was initially budgeted at NZD$26 million in 2019. However, the designer’s plans were based on historical utility plan data provided by asset owners, and no investigative works on the site were conducted prior to construction.
Almost immediately upon excavation, high volumes of previously undetected services were encountered, including power, gas and telecommunications lines installed next to the rail corridor that did not appear on utility plans.
Work was routinely delayed while the other asset owners were consulted, resulting in massive time delays, material costs and inactive labour hire. Relocating services was a last resort, so the design plans were constantly under revision, leading to further costs and time delays.
In total, 194 working days were lost due to productivity issues related to the unknown services – nearly one third of the total project time. The project is still under construction, two years behind schedule.
Had the designers undertaken proactive mapping or understood the site difficulties prior to construction, they could have accurately priced the project and minimised cost variations, and set realistic expectations for project completion, avoiding negative publicity and impact on the public.
This pattern repeats around every developed city in the world due to our lack of knowledge of the subsurface. A post-mortem report on the Sydney Light Rail scheme found the project could have been built 1.5 years quicker if they had reliable underground utility information.
Subsurface Utility Engineering
Proactive mapping to understand site risks is the first step towards keeping costs under control and mitigating cost and timeframe blowouts.
Experienced utility surveyors like Reveal use a combination of detection tools. Ground-penetrating radar (GPR), electromagnetic line (EML) tracing and visual investigation (potholing) are some of the tools used locate utilities and other geophysical objects in a prospective worksite. Preliminary reports to the design engineer and contractor help them better understand the project risks.
A comprehensive and accurate understanding of the subsurface environment in the digital planning phase can reap massive cost efficiencies:
Reduce materials costs by knowing exactly what is needed (reducing both project costs and embedded carbon emissions).
Eliminate the risk of the unknown so budget can be allocated accurately (no more surprises).
Shorten construction timeframes, minimising traffic disruption and impact on citizens and businesses.
The next step - a digital twin of the subsurface
Subsurface utility engineering techniques are only a single-purpose solution for discrete projects. Over time, the information gathered will fall out of date, and there are currently no mechanisms for sharing information between parties. Future excavations on a site will be forced to repeat the same investigation and detection process at additional expense.
Subsurface investigations produce many different formats and types of data, from photographic and reality capture images to radar scans, geospatial coordinates and more. The growing sophistication of geographic information systems (GIS) mean this information can be co-hosted and cross-referenced to create a complete picture of the subsurface.
While GIS systems can produce static “snapshots” of the data at the time it was captured, we know that the state of the subsurface environment changes constantly, both through human intervention and natural geophysical processes. For these models to remain current, we need mechanisms for information to be updated and kept “fresh”, and a method to see the accuracy and “trust score” of the what’s been collected.
This complete, accurate and living representation of the real world is known as a digital twin.
In the infrastructure technology space, digital twins are the ultimate tool for city infrastructure planning, and cities worldwide can expect to save USD$280 billion with the deployment and use of digital twins, according to a report from ABI Research.
“Cost savings can be obtained in key areas, such as energy and utilities, transportation, safety and security, and infrastructure,” Dominique Bonte, Vice President End Markets, ABI Research
However, digital twins also offer many other advantages in terms of supporting and improving sustainability, decarbonisation, and the overall quality of urban living:
“With savings estimated between $2-7 per square foot, giving a 35% cut in maintenance and operating costs, 20% boost in productivity and between 50-100% reductions in carbon emissions, this is a major change for urban areas and energy resilience.” ABI Research
Conclusion
Cities and planning departments face massive challenges in the coming years to create sustainable, vibrant living places for their growing population. Expanding and upgrading critical infrastructure is crucial to success, but without accurate, up-to-date subsurface data, projects will continue to cost taxpayers billions of dollars and run years overdue.
Cities that take proactive steps to map their underground and aggregate the information in platforms that can keep the information current will reap massive advantages in productivity, economic growth and sustainable outcomes in the 21st century.