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 »
Yearly Archives: 2024
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 »
Federal Railroad Administration (FRA) Announces $1.1 Billion Available in the Railroad Crossing Elimination (RCE) Grant Program
The inaugural Railroad Crossing Elimination (RCE) grant program was designed to eliminate or improve roadway and railroad at-grade crossings, with the goal of making roads/rails safer while improving commute times for citizens. According to the U.S. Department of Transportation website, “this program provides funding for highway-rail or pathway-rail grade crossing improvement projects that focus on improving the safety and mobility of people and goods.” The grant program helps fund projects that involve: repairing grade separations, relocating tracks, upgrading or improving protective devices, signals, or signs, maintaining at-grade crossings, and more. With safety as the top priority for the DOT, repairing and maintaining high-impact areas is critical so the potential for collisions or blockages can be prevented. Applications for funding are due no later than 11:59 p.m. EST, September 23, 2024. Visit USDOT website for more information and to apply for funding >> The GEOWEB® System stabilizes high-impact and crossing areas safely and quickly, limiting track downtime. Areas subjected to heavy stresses at bridge approaches, diamonds, turn-outs, and crossings create the highest maintenance and safety liabilities for operations. The GEOWEB Soil Stabilization System (Geocells) is effective in reducing maintenance in these high impact areas. The GEOWEB 3D Soil Confinement System has been… Read more »
Energy Infrastructure and Climate Change: Protecting Erodible Slopes in Fire-Prone Areas
Energy infrastructure is critical to the functioning of modern societies, and its protection against natural disasters and environmental threats is a top priority. Climate change exacerbates these disaster risks, with extreme weather conditions and wildfires being of particular concern, considering potential damage to the energy infrastructure and disruption of energy supply. Wildfires cause rapid, severe destruction, and, aside from damage to infrastructure, can impact our climate, vegetation, and atmosphere. To measure the size and impact wildfires have, scientists use observations from several low Earth-orbit satellites, including the Copernicus Sentinel-3. These tracking satellites gather shortwave-infrared data combined with other techniques to differentiate between burned areas and other low reflectance covers such as clouds. The European Space Agency (ESA) compiles that long-term dataset to analyze global fire trends. According to the ESA, fire affects an estimated four million square kilometers (1.5 million square miles) of Earth´s land each year [1]. That is 400,000,000 hectares (990,000,000 acres) yearly—about half the size of the United States of America, an area larger than the country of India. The United Nations Environment Programme (UNEP) Rapid Response Assessment on Wildfires compiles findings from over 50 experts from research institutions, government agencies, and international organizations around the globe, and… Read more »
Transforming Transportation Infrastructure: Protecting Road and Bridge Embankments with Geocells
In a rapidly changing world, maintaining and improving our transportation infrastructure’s resilience and sustainability has become a critical concern for civil engineers. Climate change and increasing frequency of natural disasters present an ongoing challenge to the durability of our infrastructure. In the context of road and bridge embankments, protecting these structures can be of paramount significance to the safety and welfare of the public. These structures are often subjected to fluctuating environmental conditions, heavy traffic loads, and must be able to withstand major storm events to protect embankment materials from soil washouts and the long term damaging effects of erosion. So how can civil engineers meet these growing demands without compromising sustainability or longevity? Increasingly, engineers are turning to geosynthetic solutions, such as the GEOWEB® Soil Stabilization System—a low-maintenance and eco-friendly solution for long-term protection of road and bridge embankments. In many cases, the GEOWEB Geocells offer a flexible, durable, and environmentally responsible alternative to traditional construction materials that can accommodate a wide range of infill materials, including soil, aggregate, or concrete, to establish hard or soft armor, as necessary, for protection as well as aesthetics. As we explore the capabilities of the GEOWEB Geocells, we will find that this… 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 »
Green Retaining Walls Protect an Advanced Wastewater Treatment Plant from a 500-Year Flood Event
Flood Protection Plan To meet federal requirements for flood mapping of levee-protected areas, a levee reconstruction project for the Indianapolis Southport Advanced Wastewater Treatment (AWT) plant along Little Buck Creek was part of a more extensive Deep Rock Tunnel Connector project—one of the largest combined sewer overflow projects for the City of Indianapolis. The project included plans to protect the Southport ATW plant and wastewater-processing pond from a 500-year flood event from an adjacent creek and river. To accomplish this, a wall system designed on the creek side of the levee would have to maintain a narrow profile to increase the water capacity of the creek. A Natural Erosion Protection Solution Flood events and high water flow from the adjacent creek caused significant toe erosion of the levee embankment along the north side of the wastewater treatment plant. The AWT required a long-term soil stabilization solution to combat erosive forces from Little Buck Creek’s varying depths and flows. The creek flows as low as a 1-foot depth with velocities of 3 feet per second (fps) to as high as 8 fps with a depth of 12 to 15 feet during a flooding event. The project engineer preferred a wall system… Read more »
Creep is not a factor for geocell load support
Written by: Bryan Wedin, Chief Engineer An accurate understanding of creep resistance is essential to proper material selection when using polymers, and in the case of geocells, this science is being misapplied. The definition of creep deformation is “the tendency of a solid material to move slowly or deform permanently under the influence of mechanical stress.” This potential failure mode creates fear and uncertainty among designers wherever the possibility of creep factors exists. Yes, creep can occur in almost all materials including plastics, metals, and concrete. In cases such as bridge and building design, it is important to properly understand creep factors and account for creep in engineering calculations. However, in the case of designing with geocells for load support, creep factors have no relevance. What causes creep? In order for creep to occur, two factors must be present: 1) A constant load applied to the area and 2) A sustained deformation of the geocells. Creep only applies when there is a sustained load on a material for an extended period. In a case of repeated on- and off-loading, this type of deformation would be governed by fatigue, not by creep, because it is not a constant applied load. The… Read more »
Advancing Rail Resilience: How Geosynthetics Help Achieve CRISI Objectives for Robust and Stable Infrastructure
Discover the Latest CRISI Rail Infrastructure Funding Opportunities: Apply Before the May 2024 Deadline The U.S. Department of Transportation is bolstering rail infrastructure advancements through the Consolidated Rail Infrastructure and Safety Improvements (CRISI) program. With a recent allocation of $2.47 billion, the CRISI program is set to significantly impact rail safety, efficiency, sustainability, and reliability across the United States. This funding initiative is designed to support a variety of projects that are pivotal to enhancing the nation’s passenger and freight rail systems. It represents a call to action for rail industry professionals, including engineers, planners, and project managers, to leverage this opportunity to advance their rail infrastructure projects. The deadline for application submissions is 11:59 p.m. ET, May 28, 2024. Professionals in the rail sector are urged to prepare their proposals that align with CRISI’s mission to improve the rail infrastructure’s overall landscape. For a comprehensive overview of the application process and to assess project eligibility, stakeholders are encouraged to review the Fiscal Years 2023-2024 Notice of Funding Opportunity (NOFO) available through the CRISI program. This funding presents a pivotal chance for those involved in rail infrastructure to gain the support and resources needed to propel their projects forward…. 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 »
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