Geogrid reinforced soil structures reach new heights

June 1, 2019

By Sachin Mandavkar and Mehari Weldu Reinforced soil structures are geotechnical systems consisting of reinforcing elements and primarily include mechanically stabilized earth (MSE) walls and reinforced soil slopes (RSS) (Figure 1). MSE walls and RSS are constructed by placing alternating layers of reinforcement and compacted soil behind a facing element to form a composite material …

The GMA Techline

Who is doing the testing? Q: This question relates to the number of rolls to be selected as the lot sample for specification conformance testing and refers to ASTM D4354. When I look at this standard, it appears the values in Table 1 of GRI’s White Paper #10 refer to the number of units to …

Streambank restoration using engineered bank stabilization

By Jeffery T. Hoilman and Stanley M. Miller Mountain Creek flows through the community of Red Bank near Chattanooga, Tenn., to the Tennessee River. Mountain Creek has been identified by the Tennessee Department of Environment and Conservation (TDEC 2018) as a 303(d)-listed stream, meaning that its pollution exceeds the state’s standards for one or more …

Using geosynthetics in flexible airport pavements

By Benjamin Mahaffay, Jeremy Robinson, Jeffrey Gagnon and Gregory Norwood In recent years, there has been an increasing interest to improve pavement structures through mechanical stabilization by incorporating geosynthetic products within the structure. The Geosynthetic Materials Association (GMA) has identified eight categories of commercially available geosynthetics: geotextiles, geogrids, geonets, geocomposites, geosynthetic interlayers, geocells, erosion control …

Carthage Mills installs geocell in video

May 2, 2019

Carthage Mills has released a YouTube video showing the installation of a geocell on a slope. The company carries the CX and CXW Series of geocells, which are three-dimensional, expandable panels made from high-density polyethylene (HDPE). Engineers use such geocells for containment, erosion control and ground stabilization applications. They improve the structural and functional behavior …

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Large-scale studies to evaluate the resilient modulus of geocell-reinforced pavement

April 1, 2019

The 2017 ASCE report card (ASCE 2017) on civil infrastructure assigned grade “D” for America’s roads, and this rating necessitates the adoption of more sustainable and resilient approaches in design and construction of transport infrastructures such as highway embankments and pavements. Reclaimed asphalt pavement (RAP) material has been considered as one of the sustainable options …

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Expanding a lakeside road with a reinforced soil slope

Reconstruction of Hennepin County State Aid Highway 112 is a multi-phase project. Phase 1 was completed in fall 2018. Phase 1 included reconstruction and widening of the existing roadway as well as the construction of a bike trail between the road and the lake. The roadway/trail alignment is adjacent to the shoreline of Minnesota’s Long …

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Performance evaluation of a multi-span GRS–IBS

The I-70 multi-span bridges (Figure 1) over Smith Road in Aurora, Colo., included design methodology changes that were classified as “experimental features,” and, thus, additional project funds were included for evaluation. In order to understand the geostructural performance of the multi-span geosynthetic reinforced soil–integrated bridge system (GRS–IBS), the abutment was instrumented with a vertical chain …

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The GMA Techline

Vegetation causing gases under geomembrane? Q: I have a site where we are installing a high-density polyethylene (HDPE) liner in an existing pond. Because of some residual heavy metals in the top layer of soil, I would like to strip off the top 3–6 inches (7.6–15.2 cm) of soil and vegetation. Alternatively, we could mow and …

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Yeager Airport: Deconstruction and reconstruction of the side of a mountain

Yeager Airport is located on top of a series of leveled mountains in Charleston, W.Va. Completion of the original airport construction in the 1940s required 9 million cubic yards (6.9 million m3) of soil and rock earthwork (Keller 2017). In 2005, due to Federal Aviation Administration (FAA) safety requirements, it was necessary to construct a …