An innovative cover system to close an ash/sludge impoundment

August 1, 2019  |  Case Studies, Features

By Paul C. O’Malley, José L. Urrutia and Don DiGuilio The two projects (confidential client) are industrial sites consisting of coal ash and by-product sludge located in the southeastern United States. The projects included 70 and 67 acres (28 and 27 ha) in closure areas, and the waste source con…
Reviving the Palos Verdes Reservoir—Part 4

August 1, 2019  |  Case Studies, Features

By John Heap and Chris Kelsey The active site work for the Palos Verdes Reservoir’s substantial update began in late 2016, advanced primarily throughout 2018 and concluded in the second quarter of 2019 with the filling of the reservoir. The project was immense for everyone involved, and with that …
A minitube blanket for landfill gas collection and containment

August 1, 2019  |  Case Studies, Features

By Stephan Fourmont, Pascal Saunier and Toraj Ghofrani Landfill gas (LFG) is produced during the decomposition of putrescible material in landfills. Often referred to as biogas, LFG is a source of odors and fugitive greenhouse gas (GHG) emissions. LFG is typically 40%–60% methane, which is 25 time…
Stabilization of subgrade soils during Interstate 95 lane widening

August 1, 2019  |  Case Studies, Features

By Bryan C. Gee, Eric Klein and William T. Maier The Maryland Transportation Authority (MDTA) is implementing a multiyear, multiphase project to add express toll lanes (ETLs) to Interstate 95. The ETLs are providing significant congestion relief in one of the most heavily trafficked corridors in the…
Geogrid reinforced soil structures reach new heights

June 1, 2019  |  Features

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 …
Streambank restoration using engineered bank stabilization

June 1, 2019  |  Case Studies, Features

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 p…
Using geosynthetics in flexible airport pavements

June 1, 2019  |  Features

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

April 1, 2019  |  Features

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. Reclai…
Expanding a lakeside road with a reinforced soil slope

April 1, 2019  |  Features

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 adjacen…
Performance evaluation of a multi-span GRS–IBS

April 1, 2019  |  Features

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 g…