Written by: José Pablo George, M.S., CPESC-IT, International Business Manager Microplastics, tiny plastic particles smaller than five millimeters, present a potential hazard to both wildlife and marine organisms. As revealed by a global microplastics database provided by the National Centers for Environmental Information (NCEI) and published by the National Oceanic and Atmospheric Administration (NOAA), plastic is the dominant type of marine debris in the ocean and the Great Lakes. These microplastics, usually originating from single-use, disposable plastics on land, are transported via rivers and wind into global circulation systems where they accumulate. International Measures and Guidelines: A Proactive Response to Plastic Pollution The United Nations Environment Programme´s Intergovernmental Negotiating Committee and Environment Assembly have adopted an international legally binding instrument on plastic pollution to address plastic pollution throughout its life cycle. Given the array of different types of plastics, the Sea Studios Foundation, in conjunction with Earth911.org, the Institute of Agriculture and Trade Policy, the WHO International Programme on Chemical Safety, and the US EPA, has published a Smart Plastics Guide. This guide outlines seven commonly used plastic types and their potential health hazards. There are some plastics (often used for disposable packaging) that are not easily recycled and may contain… Read more »
Posts Categorized: Geocell Confinement System
“Or Equal” Substitutions in Geosynthetics: Evaluating the Contractor’s Proposed Alternative Amidst Global Supply Chain Disruptions & Rising Costs
Written by: Michael J. Dickey, P.E., Director of Presto Geosystems As supply chain issues and project delays continue to wreak havoc in the global geosynthetics industry, Presto Geosystems has prepared this “reboot” of our tips for evaluating “or equal” substitutions to help you navigate the decision-making process when confronted with a proposed alternative geosynthetic product. According to a recent special feature article from Geosynthetic News Alerts (GNA), more oversight and diligence is needed—now more than ever—as deceptive products and inferior raw materials continue to find their way into global markets. According to GNA “Distributors and installers that place orders in good faith—particularly with overseas vendors—may wind up with rolls of geosynthetics they can’t use, and no wriggle room in compressed delivery timelines to find alternatives or otherwise rectify errors.” To protect against this, GNA goes on to emphasize the importance of vetting geosynthetics suppliers to maintain quality metrics. In light of this, Presto offers this reboot of our five tips for evaluating “or equal” substitutions to help you keep your project on the path to success amidst the chaos. Tip #1: Review Product Datasheets Closely (Be Wary of Disclaimers) Many design professionals tend to focus on the numbers shown on… 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 »
GEOWEB Geocells Combined with a Turf Reinforcement Mat (TRM)
GEOWEB® System – Research Synopsis Research Objective Measure the performance of the GEOWEB (GW) material combined with a turf reinforcement mat (TRM) (integrated system) with topsoil infill and vegetation under varying shear stresses and flow rates to quantify both hydraulic forces and corresponding soil loss. The test consisted of a series of continuous one-hour flows over the GW-TRM system at incrementally increasing discharges. The performance threshold was defined as the point at which 0.5 inches (13 mm) of soil loss occurred. Research Scenario The Research Facility Steep-Gradient Overtopping Facility (SGOF) at the Hydraulics Laboratory of the Engineering Research Center (ERCD) at Colorado State University (CSU), Ft. Collins, Colorado Test Timeframe April 2005-August 2006 Test Materials GEOWEB Soil Stabilization System North American Green C350 Turf Reinforcement Mat Scope of Test Hydraulic performance testing was conducted on an integrated system comprising the GW30V textured/perforated GEOWEB System and the North American Green C350 composite turf reinforcement mat. The C350 TRM was chosen for its known performance in the test apparatus. Six tests were conducted under the research program to measure the performance of the integrated system, identify stability threshold conditions, and quantify both hydraulic forces and soil loss. Assembling the Test Components The… Read more »
Solar Installations on Closed Landfills: Using Geosynthetics to Overcome Redevelopment Challenges
Written by: Michael Dickey, P.E. (WI, FL, GA, NC), Director Redevelopment of closed landfills and capped solid waste sites represent a unique opportunity for landfill owners, solar developers, and communities to work together to put underutilized properties back into productive use. Moreover, many such sites are conveniently located near existing transmission infrastructure and may be easier and more economical from an interconnection standpoint than rural greenfield sites. However, building over a closed landfill poses unique challenges because most landfills are covered by an engineered cap not typically designed to support loads from permanent foundations or heavy equipment. Additionally, state and federal regulations generally prohibit any activity that could potentially breach or damage the cap. Therefore, retrofitting a closed landfill for utility-scale or community solar projects requires careful planning. Ultimately, the project must not jeopardize the intent of the original cap design; that is, to protect human health and the environment. Selecting a Suitable Foundation Concrete slabs and pre-cast ballast footings are both foundation options for solar system installations on landfill caps. In general, concrete slab foundations are heavier than ballast footings and pose a higher risk of creating landfill settlement and side-slope stability issues. Ballasted footings are a lighter-weight option… Read more »
The History of Geocells
Geocell technology has come a long way over the past four decades. In its early days of development, the geocellular soil confinement system consisted of wax-coated craft paper; a plastic drainage pipe matrix fastened with staples; paper-thin, hexagon-shaped, glued aluminum; low- and medium-density recycled materials; pure polyethylene without UV stabilization; and square cells similar to old-fashioned egg carton separators. The Invention of Modern Geocell Technology In the late 1970s, the U.S. Army Corps of Engineers (USACE) contacted Presto Products Company—a private-label consumer packaging manufacturer—to develop a more robust honeycomb-shaped confinement system that would maintain load-bearing strength under heavy vehicle loads. Working with Steve Webster at the Waterways Experiment Station (WES), Presto’s Gary Bach devised a method to weld polyethylene strips to form a cellular structure. This innovative system became known as Sandgrid and was used by the military primarily for road applications. After the development of Sandgrid, Presto Products created a new business unit to focus solely on the geosynthetics business. With this expansion, Presto Geosystems® was established. Presto Geosystems and the USACE tested various resin blends and concluded that virgin high-density polyethylene (HDPE) provided superior weld consistency and structural strength. Presto Geosystems introduced the GEOWEB® Cellular Confinement System (CCS)… Read more »
Advancing the Mining Industry’s Transition to Sustainable Practices with Geosynthetics
Written by: Michael Dickey, P.E. (WI, FL, GA, NC) Mined materials are essential to our everyday lives. We use these valuable minerals in nearly every sector of the economy—they are necessary to construct roads and buildings, manufacture vehicles, build computers, and generate electricity. Additionally, the mining industry stimulates economic growth by providing employment opportunities and generating tax revenue that helps fund vital public services, such as hospitals and schools. As the mining industry navigates environmental, social, and governance (ESG) issues, there is a sense of urgency to adopt sustainable or “green” mining practices. Green mining can be defined as technologies, best practices, and mine processes that are implemented to reduce the environmental impacts associated with the extraction and processing of metals and minerals. The Mining Industry Faces Unique Challenges When it comes to sustainable development, operation, and closure of mines, the industry faces myriad challenges—not the least of which are poor soil conditions, weak subgrades, and other geotechnical challenges that can complicate miners’ efforts to meet ESG goals. In this regard, some of the more common geotechnical challenges that mine operators must contend with include: Constructing and maintaining heavy-duty haul roads. Stabilizing and protecting slopes. Tailings management and site reclamation…. Read more »
Why Geocells Outperform Geogrids for Road Construction
Written By: Bill Handlos, PE, Director of Presto Geosystems Geocells (cellular confinement) 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… Read more »
Bringing Stability to an Unstable World
With this summer’s extremely wet weather conditions across the country, building access roads is a major challenge. Muddy, soft ground is causing construction delays when it comes to moving heavy vehicles and equipment over the soft soils. Presto’s GEOWEB® Soil Stabilization System offers a way to build roads even with these site challenges using low-cost, local fill—and has been doing so for over 30 years. In fact, the GEOWEB system is the go-to solution for many oil companies in remote areas like the Canadian oil sands and the Amazon basin. Recently, EnergyNow Media featured an article on GEOWEB roads addressing the latest access challenges in the energy sector. The EnergyNow article is republished below. Reprint of recent article written by “EnergyNow Media” (North American Energy Magazine) Presto Geosystems: Bringing Stability to an Unstable World Oil and gas is a tricky business. Everything from resource extraction to site management to processing is fraught with difficulties, challenges, and trials. However, one often-overlooked aspect within this industry is that of simply being able to access the resource site in the first place. Once access is established, it’s crucial that there is a clean, stable platform to work on and transport resources back out…. Read more »
Choosing the Right Geocell
Written By: Bryan Wedin P.E., Chief Design Engineer, Presto Geosystems Not all geocells are created equal. While most manufacturers can provide similar-looking written specifications, you need assurances that the material delivered for your project is of the high quality that you expect. Important factors in the success of your geocell project include: Quality The geocell material is proven, strong, and will last Require only the highest quality virgin High Density Polyethylene (HDPE) resin Low quality or recycled resin can lead to weak and/or inconsistent seam strength, putting the success of your project at risk. Non-HDPE materials cannot match the nearly 40 years of in-ground experience of HDPE geocells and plastic alloy proprietary blends can mask cheap stiff filler materials. ISO Certification Important, but the manufacturer sets the testing protocol for the certification. Require a Certificate of Analysis (COA) for the material that is shipped to your project. An ISO certification that does not require continuous testing is lacking. Integral Components The complete solution includes proper components Non-corrosive, high-strength panel connection method (ATRA® Keys vs. weak staples or zip ties) Anchors that provide secure connections to the geocell (ATRA® stakes vs. J-hooks) Load Transfer Devices for tendon applications that are non-corrosive and… Read more »
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