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GSI/GRI-GG5 and ASTM D6706

October 7, 2009 | News, Q&A: GMA Techline

GMA techline answers from Bob Koerner Subject: GG5 I referenced GSI/GRI–GG5 on a segmented retaining wall system spec and need to know if this is correct. Supposedly on your website this standard was crossed out and noted to refer to ASTM D6706. Should I replace GG5 with the ASTM standard? Ple…

Installing prefabricated vertical drains

October 7, 2009 | Q&A: GMA Techline

From the GMA Techline Subject: Geocomposite question We are looking into installing prefabricated vertical drains to relieve excess pore water pressure for a surcharge fill. Following the information listed in Designing with Geosynthetics, 5th Edition, the statement 1-2 meters is the typical spacing…

Geomembrane installations

October 7, 2009 | Products

From the GMA Techline Subject: Geomembrane installations What are the pros and cons of letting a contractor proceed with the installation of a liner when the moisture content is lower than desired? (Marvin, New York) Reply: I have to make some assumptions before I answer your question. I assume that…

Liner thickness

October 7, 2009 | Products

From the GMA Techline Subject: Liner thickness I use an equation from your Designing with Geosynthetics, 2nd Edition, to calculate liner thicknesses. Recently, I calculated a geomembrane thickness of 100 mils for a landfill with 200ft of waste. The supplier stated that he had never seen liner that t…

HDPE welding

October 7, 2009 | Q&A: GMA Techline

From the GMA Techline Subject: HDPE welding [We are] seeking information that would assist on welding 60-mil white HDPE above 104°F. We have successfully demonstrated in the past with destructive and nondestructive testing welds that would exceed project specifications. We are currently on a lar…

CQA test frequency for geomembranes and geocomposites

October 7, 2009 | Q&A: GMA Techline

From the GMA Techline Subject: CQA test frequency for geomembranes and geocomposites I have comments from a state agency concerning CQA test frequencies and field tests conducted on geocomposites. The questions I have are: What are the typical frequencies used for CQA testing of geomembranes and geo…

Geogrid reinforcing behind rigid concrete retaining walls

October 7, 2009 | Case Studies

From the GMA Techline Subject: Geogrid use behind rigid concrete walls I was wondering if you can provide some information or guidance regarding the use of geogrid reinforcing behind rigid concrete retaining walls. My main questions are: How much can the use of geogrid reduce the lateral earth press…

Geotextile mats are curbing threats of weed invader in Ireland

October 7, 2009 | Case Studies

A non-native weed is choking off some of best fishing lakes in Ireland and disturbing water supplies in the west of the country. Biodegradable geotextile mats are providing the solution to tackling one of the most serious problems affecting the Lough Corrib ecosystem in decades. The jute matting has…

Erosion control work at Pali Tunnel in Hawaii

October 7, 2009 | Case Studies

Geotextile reinforcement is part of an effort to stabilize a slope at the Pali Tunnel on the island of Oahu. More than 10 tons of mud and debris slid onto the highway there in 2006, closing it for days before the area was cleared and deemed safe. The $700,000 Pali Slope Stabilization Project began i…

Geo at P.S. #1

October 7, 2009 | News

“Afterparty,” the installation by MOS Architects at P.S.1 Contemporary Art Center in Long Island City, N.Y., opened last June to much professional acclaim. The installation is part of the annual Young Architect’s Program run collaboratively with the Museum of Modern Art to explore …