Stabilization for Higher-Performing Pavements Ports and intermodal yards in coastal areas are more prone to pavement problems due to inherent soft, unsupportive soils and high water levels. Heavy traffic patterns and the constant weight of loaded parked trailers and stacked containers at these facilities can accelerate the degradation of the paved or unpaved surfaces and subbase materials. The repeated pressure over poor soil conditions results in settlement, ruts, potholes, and even pavement failure. These surface problems require continual, costly maintenance and interruptions to facility operations. But the problem isn’t at the surface—it’s a base stabilization problem. Transforming Base Materials through 3D Confinement Creating and ensuring a stable surface supportive of the long-term, heavy traffic needs starts with better stabilization of the base materials. The GEOWEB® 3D Confinement System is built for this function. The system’s deep, cellular network controls both the horizontal and vertical movement of unstable base soils. When vertical loads are applied, active earth pressures in the loaded GEOWEB® cells push against passive earth pressures in adjacent cells to form a stable system. The benefits of confining fill are applied to both base reinforcement and unpaved surface applications. Permeable Unpaved Pavements Utilizing the GEOWEB® 3D system at the… Read more »
Posts Tagged: GEOWEB
Build a Stronger Foundation for Infrastructure Projects with 3D Soil Confinement
It’s no secret that America’s infrastructure is desperately in need of investment. The American Society of Civil Engineers (ASCE) gave the country’s infrastructure an overall grade of D-plus in its 2017 Infrastructure Report Card—dangerously close to an outright failing grade. The ASCE estimates that the U.S. will need to spend nearly $4.5 trillion by 2025 to fix the country’s roads, bridges, dams, and other infrastructure. Our nation’s roads and bridges—commonly referred to as the “backbone” of the U.S. transportation system—received grades of D and C-plus, respectively. These transportation systems are deteriorating due to advancing age, increasing use, and inadequate funding. This degradation leads to a significant cost to users in terms of time, money, and safety. There are over 4 million miles of road in the United States, and the cost to maintain these roadways can vary greatly by state. Several factors determine maintenance costs, including the type of pavement surface, its current condition, its geographical location, average precipitation, number of annual freeze/thaw cycles, and frequency of use. Three-Dimensional Geocells Provide Solutions to Aging Infrastructure The long-term performance of infrastructure construction projects depends on the strength of the underlying soil. Through an interconnected honeycomb-like network, 3D geocells confine and stabilize… Read more »
Railroad ballast performance improvement using GEOWEB® Geocells
Each year railroads must allocate a significant portion of their capital and maintenance budget toward the creation and upkeep of high-quality ballast layers. Enduring, well-designed ballast is quite literally the foundation on which a successful rail line operates. With ballooning rail traffic carrying heavier loads than ever, GEOWEB cellular confinement (geocell) effectively takes the pressure off critical ballast systems. Oregon State University (OSU) recently performed state-of-the-art, three-dimensional dynamic Finite Element modeling to analyze the reinforcing benefit of GEOWEB geocells in railway applications. Completed in cooperation with the University of Kansas (KU), who simultaneously performed a testing program of Geocell-reinforced ballast placed over weak subgrade. The digital modeling results were reinforced by the laboratory tests and showed a significant decrease in settlement of the railway ballast when GEOWEB confinement was used. Using the GEOWEB system not only decreased settlement but also reduced pressure on point-to-point aggregate load transfer contact. This resulted in less damage to ballast aggregate particles leading to less progressive deformation and longer maintenance frequencies of the entire ballast embankment. In short, more cycles mean less track down-time for maintenance. The research results were clear. The benefits of applying GEOWEB Geocell confinement for reinforcement of real ballast over weak… 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 »
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 »
A Simple Question
How long does it take to install? It is a question we hear every day. When it comes to cost and installation rates for geosynthetic construction products, there are no simple answers to what seems like simple questions. In fact, beware of those who try to simplify determination of installation costs for their products with quick answers or charts and tables to determine construction rates. Experienced project managers and site supervisors of the crews charged with installation are in the best position to estimate productivity rates. They know best their crew’s capability and the characteristics of the site involved. The variables that need to be considered include: Crew size, talent, work ethic and workday length Temperature, precipitation and length of day (sunlight) Experience with product class Size of the project Site Access Site Conditions (see weather) Crew The optimum crew size is important. Too small and you may lose the benefits of assembly line productivity. Too large and you will find that you fall over each other and pay for extra “inspectors”. All crews are not created equally. The familiarity with tools and techniques vary greatly as does the work ethic both between crews and by region and country. Weather… Read more »
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