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Multiple-tiered retaining walls

April 1, 2007

The Norris Canyon Estates in San Ramon, Calif., east of San Francisco, are gaining a local presence not merely for luxury homes but also for the nearly half-million ft.2 of multiple-tiered retaining walls built throughout its challenging terrain. A location with 1:1 slope ratios and expansive clay soils required a major transformation to make the …

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Junction-strength requirements for roadway design, construction

February 1, 2007

By Barry R. Christopher Introduction Currently many engineers are confused about junction-strength requirements for geogrids used in roadway base reinforcement and subgrade stabilization applications, primarily because of commercialism of junction strength requirements. Some promotional efforts recommend relatively high junction strength, while others dismiss junction strength altogether. Confusing? At least one local public agency specifies a …

Sand-confinement grids from Geocell Systems

June 1, 2006

In the wake of the floods following Hurricane Katrina, officials are working to figure out how to prepare and respond to other natural disasters involving flooding, and the need for improved water barriers. The U.S. Army Corps of Engineers (USACE) is now in the process of testing new, so-called “super-levees.” The first series of modular …

Geogrids

Geogrid products are designed for reinforcement and, characteristically, are integrally connected to elements separated by in-plane apertures. Geogrids form a distinct category of geosynthetics designed for reinforcement. These products are characterized by a relatively high tensile strength and a uniformly distributed array of large apertures (openings between the longitudinal and transverse elements). The apertures allow …

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The influence of geogrid’s geometry and structure on interface behavior

European experience in pullout tests By Daniele Cazzuffi, Lidia Sarah Calvarano, Giuseppe Cardile, Nicola Moraci, and Piergiorgio Recalcati 1. Introduction The use of geosynthetics to improve the soil mechanical response has become increasingly common practice in geotechnical engineering applications. Geosynthetic materials are commonly used in soil reinforced structures, in embankment toe reinforcements on compressible ground, …