Confined Soil Could Reshape the Future of Infrastructure Design

IT DOES NOT COST ENOUGH!!

Geosynthetically Confined Soil (GCS), originally developed by Bob Barrett and Al Ruckman at the Colorado Department of Transportation (CDOT) in the early 1990s as an extension of U.S. Forest Service research, has evolved into one of the most resilient and cost-effective infrastructure technologies available today. Later adopted and promoted by the Federal Highway Administration (FHWA) as Geosynthetically Reinforced Soil (GRS), this technology has consistently demonstrated superior performance across a myriad of retaining wall solutions and bridge abutments that cost less and last longer than any in the history of transportation.

Over decades of implementation, GCS/GRS has delivered faster construction schedules, significantly lower project costs, and extraordinary safety margins. CDOT-funded research conducted by the University of Colorado Denver demonstrated safety factors exceeding 20—an unprecedented benchmark in civil engineering. To date, no documented structural failure has been observed GCS/GRS applications, including in seismic regions, positioning it as one of the most reliable earth retention and foundation systems in modern infrastructure.

Perhaps It Is Also Too Easy to Design

GCS/GRS is a composite system formed by compacted granular fill layered with closely spaced geosynthetic inclusions. By preventing lateral soil dilation, the system creates a stiff, load-distributing mass that behaves more like engineered rock than conventional soil.

This structural behavior enables exceptional load-bearing capacity, reduced deformation, and long-term durability under extreme environmental conditions. The technology’s versatility also allows for multiple facing options, including wrapped geotextiles, shotcrete, natural stone, and economical split-faced concrete masonry units. Compared to proprietary mechanically stabilized earth (MSE) systems, GCS/GRS often requires approximately 30% less cross-sectional area while using lower-cost commodity materials instead of expensive branded components.

GCS/GRS theory and performance are entirely different than quasi-tieback MSE features…GCS/GRS does not require embedment nor concrete leveling pads and there are no minimum widths. I have built them 40 feet high and 2 feet wide. Al built one 120 high and 12 feet wide. The only design mandate is external stability….we can’t fail it internally.

Performance, Longevity, and Risk Reduction

The performance advantages of GCS/GRS extend well beyond retaining walls. Bridges constructed on GCS/GRS abutments do not require expansion joints, eliminating the common “bump at the bridge” problem, and can reduce total bridge costs by roughly one-third. In practical terms, agencies can typically construct three GCS/GRS-supported bridges for the cost of two conventional bridges.

Construction speed is equally transformative. Barrett and Ruckman have successfully completed small bridge and box structures in less than 24 hours….these systems do not require wet concrete. Larger spans—including their 191-foot bridge in Montana’s highest seismic zone—demonstrate the technology’s scalability.

With projected service lives exceeding 200 years for structural systems and geosynthetic inclusions rated beyond 500 years, GCS/GRS offers unmatched life-cycle value.

By eliminating internal failure mechanisms, simplifying construction, eliminating curing delays, and maintaining tolerance to settlement and environmental variability, GCS/GRS substantially lowers technical, operational, and construction risk compared to traditional alternatives.

Despite its proven record, widespread adoption of GCS/GRS remains surprisingly limited. The primary reason is not technical—it is economic and institutional.

Unlike proprietary systems such as MSE, which are often supported by manufacturers providing design services, specifications, technical sales teams, and aggressive marketing, GCS/GRS is fundamentally a generic technology. It relies on readily available materials and straightforward engineering principles, leaving no dominant vendor with a direct financial incentive to champion its widespread use.

In an industry where innovation is often accelerated by commercial sponsorship, GCS/GRS lacks the built-in promotional infrastructure that pushes many competing systems into standard practice. This absence of “paid champions” has created a paradox: one of the safest, most cost-efficient infrastructure systems available has expanded more slowly than less effective proprietary alternatives because it does not fit the conventional business model of product-driven adoption.

Implications for Owners, Agencies, and Public Investment

For transportation agencies, municipalities, and infrastructure owners, this dynamic presents both a challenge and an opportunity. Dependence on vendor-driven systems can simplify procurement and technical support, but it may also restrict consideration of more effective, lower-cost alternatives.

GCS/GRS empowers agencies to take greater control over design, budgeting, and implementation while prioritizing performance over proprietary dependency. Beyond walls and bridges, applications such as double-sided retaining systems for rockfall barriers further expand its strategic value. CDOT testing has demonstrated that these structures can withstand impacts from virtually any scale of rockfall event, offering life-saving potential in hazardous terrain.

A Different Path Forward

The future of GCS/GRS may ultimately depend on whether the infrastructure industry is willing to evaluate innovation based on performance, safety, and public value rather than market presence alone.

As Dr. Carmen Swanwick of Utah DOT and AASHTO T-15 noted, “If someone says that’s the way we’ve always done it, it’s probably time to do things differently.”

Without a traditional commercial driver, the broader implementation of GCS/GRS will likely rely on engineers, agencies, policymakers, and institutions prepared to advocate for technologies that prioritize societal benefit over vendor profitability. The question is no longer whether GCS/GRS works—it has already proven itself across decades of successful applications. The real question is whether the industry is prepared to embrace a transformative, high-value solution that could save substantial public funds, improve safety, and redefine the future of resilient infrastructure design.

Adoption of the full suite of GCS/GRS technologies represents more than an engineering advancement—it is an opportunity to save lives, maximize infrastructure budgets, and build a more sustainable future.