According to a recent report, United States ports handled a record 50.5 million shipping containers in 2021—an increase in total container volume of 16 percent. Unprecedented demand for goods contributed to this staggering figure, and projections for 2022 do not indicate that demand will decrease anytime soon.
Ports and intermodal yards are a vital link in the nation’s supply chain, and disruptions can cause an undesirable and costly ripple effect. Because ports are susceptible to a variety of interruptions, it is imperative to design resilient port infrastructure to support the increased container volume.
Ports and intermodal yards in coastal areas are more prone to pavement problems due to inherent soft, unsupportive soils and high water levels. Soft subgrade conditions combined with heavy traffic loads from trucks, reach stackers, and gantry cranes can accelerate the degradation of paved or unpaved surfaces and subbase materials. This results in differential settlement, ruts, potholes, and an overall reduction in pavement service life. Moreover, these issues require continual, costly maintenance, and can result in interruptions to facility operations. Repair efforts typically focus on grading, patching, or resurfacing, but the problem is not at the surface—it is a base stabilization problem.
Strengthening Base Materials Using GEOWEB® Geocells
Creating a resilient pavement structure capable of withstanding long-term, heavy-duty traffic demands starts with stabilizing the base materials. The GEOWEB® Soil Stabilization System was invented specifically for this purpose. Created through a collaboration between the U.S. Army Corps of Engineers (USACE) and Presto Products Co., GEOWEB® was designed to address the needs of the U.S. military to build sand access roads capable of supporting heavy vehicle loads over soft or unstable soils. The system’s deep cellular network controls both the horizontal and vertical movement of unstable base soils. In load-support applications, when a static or dynamic load is applied to a geocell-reinforced layer, lateral earth pressures are mobilized and transferred across a three-dimensional network of interconnected cells. The layer essentially performs like a composite material, facilitating a phenomenon known as the mattress effect.
Reduce Construction Costs, Emissions with GEOWEB® Geocells
With geocells, it is not uncommon to see an overall reduction in the required thickness of the base layer in a load support application by 50 percent or more, along with an overall improvement in allowable bearing capacity. This applies to both unpaved and paved surfaces at port and intermodal yards, including container stacking yards, access roads, and chassis storage areas. This results in a reduction in upfront construction costs, and it provides long-term savings resulting from reduced maintenance and repair costs, along with fewer interruptions to facility operations.
Moreover, in many cases, geocells allow for the beneficial reuse of on-site materials, eliminating the need to purchase expensive aggregate or imported structural fill. Compared to planar geosynthetic products such as geogrids—which commonly rely on expensive, imported high-quality aggregate—geocells are highly versatile and can be filled with a variety of commonly-available and economical infill options. Infill options include sand, crushed aggregate, recycled concrete, pulverized debris, recycled asphalt, or other locally sourced materials.
These advantages not only offer the potential for savings in terms of upfront construction costs and long-term operational costs, but they also contribute to a significant reduction in carbon emissions due to less aggregate/fill processing, transportation, and handling.
Optimizing Pavement Structures Over Weak Subgrades Using GEOWEB® Geocells
When faced with weak subgrade conditions, the GEOWEB® Soil Stabilization System is ideal for project owners who may be interested in conducting a value engineering evaluation of project options. For example, the figure below provides a direct comparison of four structurally equivalent unpaved road designs over a subgrade with a CBR of 1 percent.
As shown in the above example, the unreinforced aggregate option would require more than 36 inches of aggregate to achieve minimal stability, and the planar geosynthetic option (geogrid + geotextile) would require more than 20 inches of aggregate. In contrast, GEOWEB® geocells reduce the total section thickness to only 12 inches; where suitable on-site material (OSM) is available, it is possible to limit imported aggregate to just the wearing course.
Value-Engineered Pavement Solutions for Better Performance
GEOWEB geocells can be added to port and intermodal projects to provide a value-engineered option to project owners for both paved and unpaved areas. This solution not only reduces upfront construction costs but also provides long-term savings and fewer interruptions to facility operations. For paved surfaces including asphalt, reinforced concrete, and roller-compacted concrete, the GEOWEB system decreases pressure on the subgrade to reduce differential and long-term settlement which will extend pavement life and reduce maintenance.
The selection of the GEOWEB pavement solution is influenced by loading, subgrade soils, traffic frequency, and infill type. The engineering team at Presto Geosystems works closely with engineers and project planners, offering free project evaluation services and on-site installation support. Our recommendations will deliver a technically sound, cost-effective solution based on over four decades of accredited research and testing data. Please contact our knowledgeable staff and network of qualified distributors and representatives to discuss your project needs today.