Written By: Samantha Justice, P.E., Bryan Wedin, P.E. Geocells provide one of the most powerful solutions available to engineers and contractors when designing and constructing roadways over soft and weak subgrades. With a successful track record of over 40 years, geocells have proven effective in load support applications over challenging conditions. If you’ve ever wondered how geocells work in load support applications – and the relationship between lateral confinement, hoop stress and wall tension – you’ve come to the right place. Geocells are used to alter vertical stresses beneath an applied cyclical load. When a vertical, cyclical load is applied over geocells, active earth pressures develop in the loaded cell. These pressures arise due to the friction between the infill material and the cell wall. This friction pushes back against the passive earth pressure in the adjacent cells, helping to support the load. Refer to Figure 1. The balance of active and passive earth pressures activates the hoop stress in the cell walls, which increases the stiffness and bearing capacity of infill material. The infill material is confined within the individual cells with no chance of displacement, or lateral or vertical spreading and the result is increased stiffness. In effect,… Read more »
Posts Tagged: GEOWEB
Using GEOWEB® Geocells in Landfill Capping Applications
Written by: Cory Schneider, Business Development Manager When contaminated material such as landfill waste or contaminated soil is encountered, there are typically two options available—removal of the material or placing a “cap” over it. In most cases, capping is the easier and more cost-effective of the two options. Caps serve to isolate the contaminated material, preventing people and wildlife from coming into contact with it. Factors Influencing Landfill Cap Design Landfill cap design for any particular site depends on many factors, including the type and quantity of contaminants, size of site, amount of rainfall, and future use of the area. It can consist of one or several of the following: asphalt or concrete, vegetative layer, drainage layer, and/or an impervious layer (geomembrane or compacted clay). Preventing Slope Erosion with Advanced Geosynthetic Technology When using vegetative covers, especially in sloped areas, one of the best ways to prevent long-term erosion of the cap is to confine the topsoil component using geosynthetics like the GEOWEB Soil Stabilization System (geocells). The GEOWEB Geocells, which are three-dimensional ultrasonically welded strips of high-density polyethylene (HDPE), create small pockets to hold soil in place. By doing so, the system prevents erosion or sloughing when the soil… Read more »
Dam Structure Safety Installation and Repair Using Advanced Geosynthetic Technology
Written By: Samantha Justice, P.E. Dams and Spillways Are a Critical Part of U.S. Infrastructure With over 91,000 structures nationwide, dams and spillways are essential for controlling flooding, water distribution, and providing hydroelectric power. However, these structures cannot last forever. The average age of dams and spillways in the U.S. is now 61 years, significantly over the typical 50-year lifespan of these structures. Aging infrastructure can lead to serious consequences if safety precautions are not taken or measures are not implemented to address identified problems promptly. Continual inspection and upkeep are crucial for any dam manager. The 2021 Infrastructure Report Card by the American Society of Civil Engineers rated the condition of U.S. dams with a “D” grade, highlighting the pressing need for repairs and maintenance (Home). State and federal regulations provide a framework for assessing and maintaining dam and spillway structures, requiring at least yearly audit inspections to identify areas needing repair or replacement. Performing these repairs can help extend the lifetime of dams, maintaining essential services without excessive costs or increased failure potential. Understanding Areas of Concern for Existing Structures The vast majority of America’s rivers and lakes have existing dams and spillways, and as such, very few… Read more »
White House Provides Clarification on Build America, Buy America (BABA)
The White House released guidance on the Build America, Buy America (BABA) initiative, an important component within the $1.2 trillion Infrastructure Investment and Jobs Act (IIJA) from 2021. BABA stipulates that certain products must be manufactured in the U.S. to qualify for federal funding in infrastructure projects and emphasizes the use of domestically produced construction materials. As the faucet opens for IIJA projects, make sure your project has certainty and you are building with quality materials you can trust, 100% made in the USA. BABA Highlights: Scope: The BABA guidelines apply to federally funded infrastructure projects, including those under the IIJA. Material Categories: BABA focuses on three primary categories: iron and steel products, manufactured products, and construction materials. Notably, the list has been expanded to include engineered wood but excludes coatings, paint, and bricks based on feedback. Made in America Criteria: To wear the “Made in America” badge, a product must be produced in the U.S., with at least 65% of the cost of its components sourced domestically. This will further increase to 75% in the calendar year 2029. Included Materials: The guidance specifically lists plastic and polymer-based products, non-ferrous materials, glass, fiber-optic cable, engineered wood, drywall and lumber. Implications… Read more »
Geocell Technology Proves Effective in Solving Soil Stabilization Challenges for Solar Farms on Underutilized Lands
With the increasing demand for clean energy, there is a growing interest in repurposing underutilized lands for solar farm developments, particularly abandoned mines, capped landfills, brownfields, and other unused areas. These locations offer a unique opportunity to transform unused spaces into sources of renewable energy, and can be particularly enticing because they are often situated near established transmission infrastructure. This makes the interconnection process simpler and more cost-effective than connecting to remote greenfield sites. In addition to contributing to the shift toward sustainable energy sources, the development of solar farms on underutilized lands can create jobs, generate revenue, and bring new life to areas that have been neglected or forgotten. However, poor soil conditions can pose significant challenges for solar farm developers. To ensure the long-term success of solar projects, factors such as erosion control, stormwater management, and site access must be carefully considered during the design and construction phases, especially when repurposing underutilized lands for solar farm developments where the site conditions may be less than ideal. GEOWEB® Geocells: A Versatile Site Development Solution for Solar Projects Geosynthetics, specifically geocells, can be highly effective in mitigating the challenges posed by poor soil conditions during the development of solar farms…. Read more »
Why Geocells Outperform Geogrids for Road Construction
Geocells (cellular confinement system CCS) offer a more effective and practical 3D design solution to load support challenges than multilayered 2D geogrid efforts. Geocells transfer applied loads instantaneously, delivering practical soil stabilization in a product that is fast and easy to install. How do geogrids work? Geogrids rely on rutting, displacement and lateral movement of the road material to activate the load support reaction of the product. As shown below, failure of the driving surface must occur before the geogrid reacts. As a result, rutting and soil displacement is a prerequisite reality to the system. Since the geogrid is two-dimensional, material not located directly within the plane occupied by the geogrid is free to move, shift and displace. It is essential that geogrids are placed in a flat or a pre-tensioned manner—but that is not practical in a construction environment. It is common to see geogrids unrolled over a prepared grade with an undulating surface. As aggregate is placed over the top of the geogrid, the material kinks and waves, further warping the 2D plane. The geogrid is rarely pulled tight during installation which does not allow full tension under load. Geogrids are difficult to… Read more »
7 Key Factors to Choosing the Right Geocell
Choosing the Right Geocell Does excellent quality and support matter to you? Of course it does. But, you are smart enough to know that there is no free lunch. Low cost alternatives are less expensive for a reason. So, what do you need to look for to recognize the right geocell for your project? Quality Feedstock Insist upon verifiable proof that your geocell is manufactured only with virgin high density polyethylene. While it is possible to achieve poor weld strength with virgin materials, it is impossible to achieve consistently excellent weld strength unless only virgin high density polyethylene is used. Integral Components Choose a geocell that offers connection components, tendons, stakes, load transfer clips and installation tools that are specifically tailored for the system. Using rope, staples, bent rebars (J hooks) and zip ties that are not specifically designed for use with a geocell engineered solution is unwise and potentially catastrophic. Use only designs that recognize the critical nature of these components to the overall success of the project. Experience and Warranty Choose a manufacturer who has thousands of projects and decades of experience. It is shocking how little some manufacturers understand about the principles and practices of engineering and… Read more »
Are material shortages delaying your road construction projects? Here is how to stay on schedule and within budget.
Written by: Bryan Wedin, P.E., Chief Design Engineer Road construction is booming, and this trend is expected to remain strong due to high demand and the Infrastructure Investment and Jobs Act (IIJA), which includes investments across many sectors, including public infrastructure. Along with this boom, the road construction industry has been dealing with inflation-related cost increases and limited availability of construction materials. The industry has been impacted by supply-chain interruptions and shortages for many roadway materials including lime, cement, and even aggregate. These materials are typically used for roadway base construction, which means road construction projects that use these materials may be subject to delays. Due to these shortages and delays, on-site material or sand-filled GEOWEB® geocells can provide a cost-effective, readily available substitute for base materials–especially where native subgrade conditions consist of weak or soft soils. GEOWEB® Geocells for Roadway Base Stabilization The GEOWEB geocells have been used for load support and foundation applications worldwide for more than 40 years. Developed in collaboration with the U.S. Army Corps of Engineers (USACE) in the late 1970s, Presto co-invented the technology now known as geocells or a cellular confinement system (CCS). The early applications of geocells consisted primarily of stabilized, expedient… Read more »
How Geosynthetics Are Uniquely Poised to Help Alleviate Congestion at U.S. Ports
Written by: Michael J. Dickey, PE, Director and Bryan Wedin, PE, Chief Design Engineer On May 6, 2022, the Maritime Administration (MARAD) released an amended Notice of Funding Opportunity (NOFO), allocating over $234 million for port infrastructure development in 2022. Adding to the previously appropriated amount of $450 million from the Infrastructure Investment and Jobs Act (IIJA, or Bipartisan Infrastructure Law), this will bring the total amount available for port improvement projects to $684 million for FY2022. The significance of this investment comes at a crucial time. According to the American Association of Port Authorities, the pandemic has laid bare the need for a transport system that is able to surge and stretch across all links—from sea, to land, to rail, to warehouse, to consumer. The question is, how can this funding be used to meet this need quickly and cost-effectively? The answer may lie in a strategy implemented in 2021 in the state of Georgia to alleviate congestion at the Port of Savannah. The Georgia Port Authority, in partnership with Norfolk Southern, implemented a solution that has caught the attention of other U.S. port authorities and Class I railroads using what is being referred to as “pop-up container yards”…. Read more »
Protecting Environmental Geomembrane Covers With Suspended GEOWEB Geocells
Economic pressure, the desire for green solutions, and the intensification of climate extremes have converged to create a need for better methods to effect soil stabilization. Fortunately, a proven technology exists that addresses issues associated with these conditions and provides a more stable cover solution for landfill covers, lagoons, stormwater containment basins, and other geomembrane-covered systems. Soil, aggregate, and concrete protective covers over geomembranes can be secured against known gravitational, hydrodynamic, and seismic forces using the GEOWEB® Soil Confinement System. Soil and aggregate are commonly used as a protective cover over liners on slopes of 3H:1V or less. However, when slope gradients are greater, unconfined soil and aggregate covers are typically unstable and not used. In arid areas, cover depth may range from 75 mm (3 in) to 150 mm (6 in). Where conditions support vegetation, cover depth may range from 100 (4) to 600 mm (24 in) or greater where the final depth is a function of the characteristics of the desired vegetation. Regardless of cover depth, if an extreme rainfall event occurs that is 10%, or greater than what would typically be expected, soil mass increases, assumed friction angles decrease, and factors of safety for soil stability drop to… Read more »
800.548.3424
