|
| |
Erosion control supports space exploration
NASA Kennedy Space Center installs mattress protection system to prevent bridge scour. NASA Kennedy Space Center (KSC) in Cape Canaveral, Fla., battled scour problems around each bascule pier of four bridges throughout the KSC's channel and fender systems. The bascule piers support the drawbridge gears and may also support a guardhouse on top of the bridge. Triton Marine Mattresses were selected for their scour protection performance, constructability, adaptability, and durability in a challenging, submarine environment. Also, the coastal and waterway revetment system was much more cost-effective than the alternatives.
ID: 4393
Publication: Rebuilding America's Infrastructure - December 2012
Publisher: ZweigWhite
View this Document
Author: Jeff Fiske
 |
Digging into Landfill Design
Since Congress mandated sanitary landfills in 1976, landfill design has evolved into a creative science.
ID: 4392
Publication: Waste360 - February 2012
Publisher: Penton Media
View this Document
Author: Mike Fickes
|
Springs Eternal
Tazewell, Tenn., is a small town situated on the northern slope of Wallen Ridge in the Appalachians. Fiberweb's Brian Whitaker writes on how the construction of a highway bypass near the community caused a significant sediment threat to the area's natural springs. To alleviate concern and meet increasing regulatory scrutiny, the project team opted to use a 3-D geotextile geocelluar system to filter stormwater runoff and keep sediment out of the springs. Tests conducted by the site's consultants found that the nonwoven geotextile-based geocell units achieved an average daily turbidity limit of 280 NTUs. Runoff from a typical construction site measures tens of thousands of NTUs. Read about this site success story.
ID: 4391
Publication: Geosynthetica - February 2012
Publisher: Geosynthetica
View this Document
Author: Brian H. Whitaker
|
The Breadbasket’s Biomass Belt
The Midwestern United States' agriculture industry includes significant dairy, beef cattle, swine and poultry operations. Nearly 1/3 of the US anaerobic digestor operations are located on Midwestern farms now, but the 33 MW they produce stem represent only about 2 percent of the region's AD capacity. BIOMASS Power and Thermal's associate editor Anna Austin writes about the gap in the March 2012 issue. Read the article online.
ID: 4390
Publication: Biomass Power and Thermal - March 2012
Publisher: BBI International
View this Document
Author: Anna Austin
|
Time and temperature effects on geomembrane strain from a gravel particle subjected to sustained vertical force
Experimental data is reported that quantifies how time (up to 10 000 h) and temperature (from 22 to 85 °C) impact tensile strains in a 1.5 mm thick high-density polyethylene geomembrane -- with a compressible clay liner beneath it -- that are induced by an overlying gravel particle when subjected to a sustained vertical force. At an average applied stress of 250 kPa and clay water content of 16%, tensile strains were found to increase by 1.25 times as the temperature was increased from 22 to 55 °C after 1000 h. Similarly, strains were found to increase by factors between 1.2 to 1.3 as time was increased from 10 to 1000 h. Based on the measured data, time–temperature superposition (tTS) was then used to develop an approach to predict long-term geomembrane strains from gravel indentations. The tTS approach was validated against independent experiments conducted for 10 000 h (1.14 years) as it was found that the predicted strain of 19% was very close to the measured strain of 18%. Provided that the physical properties of the geomembrane do not decrease abruptly, the results suggest that the tTS approach developed can be used to provide estimates of long-term geomembrane strains.
ID: 4388
Publication: Canadian Geotechnical Journal - Published Online in February 2012
Vol: 49
Publisher: NRC Research Press
View this Document
Author: A. Sabir, R.W.I. Brachman
|
Short- and long-term leakage through composite liners. The 7th Arthur Casagrande Lecture
The factors that may affect short-term leakage through composite liners are examined. It is shown that the leakage through composite liners is only a very small fraction of that expected for either a geomembrane (GM) or clay liner (CL) alone. However, the calculated leakage through holes in a GM in direct contact with a clay liner is typically substantially smaller than that actually observed in the field. It is shown that calculated leakage taking account of typical connected wrinkle lengths observed in the field explains the observed field leakage through composite liners. Provided that care is taken to avoid excessive connected wrinkle lengths, the leakage through composite liners is very small compared to a typical GM or CL alone. It is shown that the leakage through composite liners with a geosynthetic clay liner (GCL) is typically much less than for composite liners with a compacted clay liner (CCL). Finally, factors that will affect long-term leakage through composite liners are discussed. It is concluded that composite liners have performed extremely well in field applications for a couple of decades and that recent research both helps understand why they have worked so well and provides new insight into issues that need to be considered to ensure excellent long-term liner performance of composite liners — especially for applications where the liner temperature can exceed about 35 °C.
ID: 4389
Publication: Canadian Geotechnical Journal - February 2012
Vol: 49
Issue: 2
Pages: 141
- 169
Publisher: NRC Research Press
View this Document
Author: R. Kerry Rowe
|
The need for erosion control material specifications
In the February/March 2012 issue of Geosynthetics, Dr. Robert Koerner of the Geosynthetic Institute (GSI) notes that the field lacks generic specifications for erosion control materials (as well as generic specs for various other geosynthetic materials). He writes, "...a reasonable case can be made that generic specifications have significantly aided both geotextile materials (e.g., via AASHTO specs) and geomembrane materials (e.g., via GRI specs). Such specifications address most common situations and also provide a platform from which unusual or atypical site-specific conditions can be implemented." Read more in Dr. Koerner's column on this pressing issue.
ID: 4383
Publication: Geosynthetics - Feburary/March 2012
Publisher: IFAI
View this Document
Author: Robert Koerner
|
NTPEP: Making Best Management Practices Better - Part I
Erosion, sediment, and stormwater runoff have an unquestionably critical impact on the quality of our environment. The EPA estimates that forthcoming new rules will cost more than $900 million annually to keep pace with site control needs. Commonly, the erosion and sediment controls that are selected are referred to as best management practices, or BMPs. But what puts the "B" in BMP? In this two-part series, Katie Westfall writes about the positive impact the National Transportation Product Evaluation Program (NTPEP) and the implementation of large-scale (or full-scale) erosion and sediment control testing are having on the field. This article has been updated from its initial version in September 2011.
ID: 4384
Publication: Geosynthetica - February 2012
Publisher: Geosynthetica
View this Document
Author: Katie Westfall
|
NTPEP: Making Best Management Practices Better - Part II
Erosion, sediment, and stormwater runoff have an unquestionably critical impact on the quality of our environment. The EPA estimates that forthcoming new rules will cost more than $900 million annually to keep pace with site control needs. Commonly, the erosion and sediment controls that are selected are referred to as best management practices, or BMPs. But what puts the "B" in BMP? In this two-part series, Katie Westfall writes about the positive impact the National Transportation Product Evaluation Program (NTPEP) and the implementation of large-scale (or full-scale) erosion and sediment control testing are having on the field. This article has been updated from its initial version in September 2011.
ID: 4385
Publication: Geosynthetica - February 2012
Publisher: Geosynthetica
View this Document
Author: Katie Westfall
|
Benson Elected to National Academy of Engineering
The awards are piling up. Craig Benson, a Wisconsin Distinguished Professor and Chair of Civil and Environmental Engineering of Geological Engineering at University of Wisconsin–Madison, has been elected to the National Academy of Engineering (NAE). The American Society of Civil Engineers (ASCE) recognized Benson recently as well in selecting him to deliver the prestigious Ralph B. Peck lecture in 2012. In the NAE release, the Academy wrote that Benson has contributed "...improvements in design, construction, and monitoring of earthen liners and covers for municipal hazardous and radioactive waste landfills."
ID: 4386
Publication: Geosynthetica - February 2012
Publisher: Geosynthetica
View this Document
Author: Chris Kelsey
|
Benson and Daniel to Deliver Key Lectures at Geo-Congress 2012
The Geo-Institute of ASCE's annual congress offers an exceptional opportunity to interact with the international geotechnical engineering community on some of the most pressing topics. Geo-Congress 2012 will be held in Oakland, California 25-29 March 2012. The theme of the event is "State of the Art and Practice in Geotechnical Engineering" and some noted engineers with a geosynthetics background (Craig Benson and David Daniel) will deliver two of the three big lectures: the Ralph B. Peck and Karl Terzaghi Lectures.
ID: 4387
Publication: Geosynthetica - February 2012
Publisher: Geosynthetica
View this Document
Author: Chris Kelsey
|
Steps for Addressing Sedimentation in Subsurface Water Storage Systems
In a special section on Urban Development, Kate Wright looks at subsurface storage strategies for water, including geotextile-wrapped storm chambers and holding structures.
ID: 4381
Publication: Waterworld - February 2012
Pages: 30
- 30
Publisher: PennWell
View this Document
Author: Kate Wright
|
|