HDPE Plays Key Role in Renovating National Landmark Washington D.C. is home to some of the United States' most prized and revered memorials. To the nearly 24 million people who visited the National Mall in the last year, the Reflecting Pool was more science project than a iconic tourist stop. Several key improvements were needed to keep the largest and most famous reflecting pool in the capital sustainable for years to come. The pool, originally constructed in the early 1920s, has been relatively untouched in terms of improvements over the years. The pool was prone to leaking, holding stagnant water, and called upon the city's drinking water resources to fill the pool to the tune of nearly 20 to 30 million gallons per year. The Louis Berger Group, Inc. served as the consulting firm that offered engineering, architecture and other development resources for the project. When drafting the solutions to the reflecting pool's problems, engineers chose a series of unique solutions. The goals of the $30.7 million project included replacing the leaking concrete pool; retaining the original coping stones of the pool; installing a highdensity polyethylene (HDPE) pipeline and a filtration system for drawing water from the Tidal Basin rather than using the city water; installing a system for cleaning and recirculating the water; installing new, wider sidewalks adjacent to the pool to replace the dirt paths; resurfacing the Elm Walks on the north and south sides of the pool; adding new lights and benches; and improving accessibility and security measures. The project is the National Park Service's largest project using American Reconstruction and Recovery Act funds. The project, which began in November 2010, revolved around approximately 2,400 wooden pilings that were driven into the ground until hitting the bedrock 40 to 50 feet below. The timber pilings were spaced apart every 12 feet, 9 inches throughout the 2,029footlong pool. The piles were used for the foundation design due to the presence of compressible fill materials beneath the Reflecting Pool, which was built on tidal basin sediments. “The pile foundation was designed to accommodate the pool slab, water weight and crowd surge load,” said James Stroup, P.E. LEED AP, technical project manager for Louis Berger Group. “Previously, the Reflecting Pool slab was not supported on piles, and as a result had settled, cracked and separated from the pilesupporting coping stone.” Pipe Selection While the unique piling system solved the issue of supporting the 12,000 cubic yards of concrete for the new pool, the question remained of what infrastructure to install to support the water within the renovated design. One of the key project requirements set forth by the National Park Service was sustainability.
Transcript
HDPE Plays Key Role in Renovating National LandmarkWashington D.C. is home to some of the United States' most prizedand revered memorials. To the nearly 24 million people who visitedthe National Mall in the last year, the Reflecting Pool was morescience project than a iconic tourist stop.
Several key improvements were needed to keep the largest and mostfamous reflecting pool in the capital sustainable for years to come.The pool, originally constructed in the early 1920s, has been relativelyuntouched in terms of improvements over the years. The pool wasprone to leaking, holding stagnant water, and called upon the city'sdrinking water resources to fill the pool to the tune of nearly 20 to 30million gallons per year.
The Louis Berger Group, Inc. served as the consulting firm that offeredengineering, architecture and other development resources for theproject. When drafting the solutions to the reflecting pool's problems,engineers chose a series of unique solutions. The goals of the $30.7million project included replacing the leaking concrete pool; retainingthe original coping stones of the pool; installing a highdensitypolyethylene (HDPE) pipeline and a filtration system for drawingwater from the Tidal Basin rather than using the city water; installing asystem for cleaning and recirculating the water; installing new, widersidewalks adjacent to the pool to replace the dirt paths; resurfacingthe Elm Walks on the north and south sides of the pool; adding newlights and benches; and improving accessibility and securitymeasures. The project is the National Park Service's largest projectusing American Reconstruction and Recovery Act funds.
The project, which began in November 2010, revolved aroundapproximately 2,400 wooden pilings that were driven into the ground until hitting the bedrock 40 to 50 feet below. Thetimber pilings were spaced apart every 12 feet, 9 inches throughout the 2,029footlong pool. The piles were used forthe foundation design due to the presence of compressible fill materials beneath the Reflecting Pool, which was builton tidal basin sediments.
“The pile foundation was designed to accommodate the pool slab, water weight and crowd surge load,” said JamesStroup, P.E. LEED AP, technical project manager for Louis Berger Group. “Previously, the Reflecting Pool slab was notsupported on piles, and as a result had settled, cracked and separated from the pilesupporting coping stone.”
Pipe Selection
While the unique piling system solved the issue of supporting the 12,000 cubic yards of concrete for the new pool, thequestion remained of what infrastructure to install to support the water within the renovated design.
One of the key project requirements set forth by the National Park Service was sustainability.
“It was not considered sustainable or environmentally sound to usewater treated to drinking water quality to fill the Reflecting Pool,especially given the volume required,” said Stroup.
“Even with the reduced volume of the redesigned pool, this seemedlike an avoidable waste of a valuable and limited resource. In order todesign a more sustainable site, a primary design objective was to findalternate water sources to fill the Reflecting Pool. After performing alifecycle cost analysis, Tidal Basin water with filtration anddisinfection was found to be the most viable option.”
The water in the pool won’t be safe for human consumption, but byfiltering and disinfecting the Tidal Basin water, the pool will achievethe clear water required to achieve the same reflection of the past.
Engineers also kept the piping connection between the ReflectingPool and the city’s water supply should it be needed as an alternativesource or for cleaning purposes.
HDPE was chosen for the water supply and circulation system for theReflecting Pool after looking at several factors.
“Once correctly welded via butt fusion or electrofusion, HDPE jointsare considered completely restrained,” stated Stroup. “This was
particularly important as many of the lines will be located beneath the Reflecting Pool and will not be accessible.”
Other pipe materials were considered for the project, but HDPE was proven to be the best fit given the constraints ofthe project and environmental conditions. Looking at costs, the material and installation of HDPE was even withpolyvinyl chloride (PVC) and ductile iron (DI).
One more site constraint was that the environment was once marshland, which lends itself to differential settlement onan unsupported infrastructure. HDPE’s flexibility was a key factor to combat this possibility, due to its ability to toleratepotential differential settlement without breaking.
The final factor in HDPE’s selection is that the pipe material will reportedly not tuberculate or support biologicalgrowth.
Pipe Fusion
To fuse the more than 3 miles of HDPE pipe to be installed under the reflecting pool and to the Tidal Basin, CormanConstruction enlisted the help of Ferguson Industrial Plastics. Ferguson recommended a range of McElroy pipe fusionproducts to be used on the project. Consultants from Ferguson also provided training and qualification testing ofCorman Construction personnel to perform the pipe fusion process.
The two key fusion machines used were the Rolling 28 and Pit Bull®14. The Rolling 28 offered Corman the flexibility to fuse pipes of anysize between 2inch IPS and 8inch DIPS. The wheeled chassis of the28 allowed workers to tow or pull the fusion machine from the pipeyard next to the reflecting pool into the work area each day.
The Pit Bull 14 is a compact and lightweight fusion machine capableof fusing pipes from 1inch IPS to 4inch DIPS. Without a chassis, the14 is capable of going into ditches and tight confines to fuse lengths ofpipe together, as well as fusing any tees, ells or other fittings that arecoming off water lines.
Under the reflecting pool, 3 and 4inch piping is most prevalent.Those pipes connect with larger diameter pipes to reach the watertreatment building. A 10inch line connects the Tidal Basin to thewater treatment facility.
The Lincoln Memorial Reflecting Pool has been a sacred memorial to the American people since its originalconstruction in the early 1920s. With the use of HDPE, a piping material capable of lasting more than 100 years,there’s a reason to believe that the latest renovation will be sustainable for generations to come.
Through the American Reconstruction and Recovery Act and the diligent work of the National Park Service, LouisBerger Group, Corman Construction and many others, this memorial will be reinstated to its original glory.
Sincerely,
Tyler Henning
P.S. – Do you have an interesting job site that you would like to share? McElroy is always looking for fusion job siteswhere HDPE is being used and fused to solve an infrastructure problem. Contact Tyler Henning, public relationsspecialist at (918) 8319286 or by email at [email protected]
Introducing the DataLogger 4The McElroy DataLogger® 4 is used to record and document key parameters of thefusion process. This costeffective device can be used to verify that proper fusionprocedures have been followed prior to installation. The DataLogger consists of arugged, handheld computer as the recording device connected to a pressure sendingdevice. The pressure sending device digitizes and sends pressure data to the handheldcomputer to generate joint reports for infield review or transfer to a desktop computerfor archive or further analysis.
The DataLogger 4 features FusionGuide™, which gives a faster go/nogo interpretationof graphs generated by the DataLogger. Trained inspectors can look at theFusionGuide data to determine if a fusion joint was fused with correct pressure andtimes according to supported standards.
Handheld Computer Features
FusionGuide™ visual graph interpretationWired model for fusion operations up to 3,000 PSITransfers joint reports to PC via standard USB port and Microsoft® WindowsMobile Device Center or ActiveSync®Generates reports in imperial or metric unitsFive installed languages (English, Spanish, Portuguese, Russian and Simplified Chinese)Support for butt fusion, sidewall fusion and dualcontainment fusion operationsOnscreen coaching leads operator stepbystep to generate joint reportsInternal battery powers handheld computer and datacollection deviceOperator uses own pyrometer
Have you been keeping an eye on your 2012 McElroy Calendar? In February, we offered calendar owners theopportunity to win a free McElroy Tape Measure.
Congratulations to David Mason of Climatech and Nicholas Wozniak of Jacobs Engineering!
Our next contest is in April for some useful McElroy Drink Coasters, so make sure you circle the date on the calendarand enter to win!
No, McElroy is not fusing on Mars. These fusion pictures come from David Lomman of Outback Pipe and CivilConstructions. Using two TracStar® 618s, Dave and his crew are fusing in the Pilbara, which is known for its red earth.The project in Northwest Australia involved relocating 160mm through 400mm HDPE pipe on a mining site, with thepiping being used for potable water, slurry and sewage lines.
Outback Pipe and Civil Constructions were able to reduce weld times by using higher pressure welds that can beachieved by McElroy 618 machines. The Australian group also had a number of challenges fusions, including a dualtiein of a 355mm line on a tight schedule.
If you have photos from a jobsite, we'd love to see them! Yours may be chosen for the next issue of McElroyConnections. Simply email your photos to Tyler Henning, at [email protected].
Check out this tool that destructively tests fusion joints – the Guided Side Bend Tester. #HDPE #pipefusionhttp://ow.ly/9DquTMar 13thWant to read about the In Field Tensile Tester in action? Here’s how it helped one Florida contractor on a#HDPE job: http://ow.ly/9yxOD Mar 9thWhat's this In Field Tensile Tester look like? Check it out on our Flickr site: #HDPE #pipefusionhttp://ow.ly/9xaV4Mar 6thMcElroy’s In Field Tensile Tester qualitatively tests #HDPE fusion joints in the field. Find out more about thetester here:... Mar 6thMcElroy is focusing on Quality Assurance Tools this month. Stay tuned for a trivia contest at the end of themonth. Trivia will come from... Mar 6thYou can now download the McCalc app from the Amazon App Store in addition to the Android Market.Mar 1stPittsburg, KS is replacing some of its first sewer lines with #HDPE and pipe bursting...read here:http://ow.ly/9jl1pFeb 27th
