For related articles: www.erosioncontrol.com gravel was selected to use as backfill, and a stone-shooter conveyer was used to deliver and fill around the steel pipes, ensuring proper drainage and preventing damage to the corrugated pipes during the backfilling operations. Jackson says about 3,800 tons of this stone was used around the multiple corrugated steel pipes, which were placed in two underground pond struc-tures engineers named Alpha and Beta. “We needed a large space to handle the anticipated runoff for the size of this site, and there wasn’t one place to establish a single underground pond, so we needed to utilize two basins,” he says. “Alpha uses solely 8-foot-diameter cor-rugated steel pipes, and Beta has 5-foot and 8-foot pipes. All are aluminized steel, which offers substantial corrosion protection and long service life.” Large-diameter steel pipes offer certain flexibility, Freeman explains, “as you can do any geometry you want, and corrugated steel fabrication allowed us to provide a tailor-made system that is very economical. Other products have certain limitations that can make installation, repairs, or modifications cumbersome or bulky. “Since we needed very large diam-eters, and plastic price increases dramatically once you get above 5-foot diameters, corrugated aluminized steel was perfect. We get our sheet product from AK Steel of West Chester, OH, who offers the different coatings, and then we manufacture the pipes at Lane Enterprises, adding the corrugations before forming the pipe on a spiral pipe mill. All of the fabrication was done at our Bealeton, VA, plant and sold through Colonial Construction Materi-als, a local dealer of our products.” Jim Evans, senior research engineer at AK Steel, offers a look into the back-story of corrugated steel pipe. “For our corrugated steel pipe customers, AK Steel primarily uses our electric fur-nace located just north of Pittsburgh in Butler, PA, which uses 100% scrap —that is, recycled—steel, to create the first step of slab steel,” he explains. Next, he says these slabs are trans-ported to Middletown, OH, outside Cincinnati, “where they are hot-rolled, MAY 2017 then pickled to remove scale, and then cold-reduced to the final customer thickness. Last, we then hot-dip-coat this at our Middletown works.” Evans explains that in 1899, the Middletown facility was the site where George Verity founded the flagship facility for the original steel company, then called American Rolling Mill Company, known later as ARMCO and now as AK Steel. After reaching customer-specified thickness, the product is known as Aluminized Type 2 Steel, which was originally developed by ARMCO. “The steel is coated in commercially pure molten aluminum with 1.5 mils coating on each side, after being continuously annealed in a reducing atmosphere. These coils of coated steel are then shipped to our customers that manu-facture and corrugate pipe for culverts, storm drains, and detention systems. Corrugated coated pipe products are then used by their customers to solve the very important environmental puzzles to responsibly manage storm-water and groundwater,” says Evans. Jackson says that when the devel-opment is finished, the surface area of Alpha will be a community public space, while Beta will have an overly-ing rain garden that drains downward to the corrugated systems, “which is why we used the smaller-diameter cor-rugated pipe in that section.” When benchmark of 80% devel-opment is reached, which Freeman anticipates in about two years’ time, the underground detention basin will be flushed and cleaned via vacuum truck, then the temporary bulkhead panels of the filtration collectors, “which we installed to block off the perfora-tions of the pipes for the short term,” will be removed. “Once the panels are removed, everything will flow to Alpha and Beta, allowing a permanent func-tioning of the drainage and stormwater management as planned.” It’s a good bet that Downton Abbey’s Lord Grantham would have eagerly traded his gold chain of office for some geotextile and corrugated pipe to manage drainage on that 5,000-acre estate! EC Barbara Hesselgrave is a writer special-izing in environmental topics. SPILLDAM ENVIRONMENTAL, INC. SILTDAM ™ Turbidity Control Curtains: designed, engineered and manufac-tured to meet the demanding site requirements of our customers. Marine Construction Demolition Dredging Remediation Erosion Control Shoreline Revetment Options include: s IN MM �c;IN
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