Hanover Architectural Products, Unilock LLC craft pavers for Washington, D.C.’s Lincoln Memorial and Chicago’s Buckingham Fountain, landmarks along trails blazed by White House-bound Barack Obama
As then-President-elect Barack Obama watched a host of musicians and other celebrities pay tribute to him on the steps of the Lincoln Memorial in Washington, D.C., two days before he took the Oath of Office, he probably was unaware that just days before crews had been hard at work renovating the monument’s East Plaza.
Meanwhile, back in the President’s home town of Chicago, work began in October and continued into early February on the Buckingham Fountain Renovation Project in Grant Park Û the setting for Obama’s Election Day victory speech. When completed, Phase 1 of the job will be the largest decorative permeable paving project in the nation.
LINCOLN MEMORIAL, WASHINGTON, D.C.
We knew after Obama was elected that the pressure was on, says Skanska USA’s Giancarlo Bulfon, assistant project manager on the East Plaza. We knew he wanted to have a ceremony at the Lincoln Memorial, since both Lincoln and Obama were from Illinois.
In fact, Skanska’s East Plaza subcontractor finished the paver bed construction and installation one week ahead of schedule, which also took into account the year-long, post-inauguration celebration marking Lincoln’s birthday bicentennial.
When the work was completed, more than 14,000 pavers were manually installed. Pennsylvania’s Hanover Architectural Products Û no stranger to high-end, specified projects Û supplied its charcoal or tudor-colored Prest Paver stones in 12-in. and 24-in. square sizes, weighing as much as 100 lbs., with local subcontractor Metro Paving doing the actual installation.
The specific colors were selected by the National Park Service (NPS) board of directors, because they distinguished and accented the historical marble that makes up the steps of the memorial, which draws more than 3.6 million visitors Û or at least 14.4 million feet walking up and back the East Plaza Û each year. The NPS expects these pavers to last 80 to 100 years, Skanska’s Bulfon says. They’ll only get foot traffic, so that shouldn’t be a problem. But, the board approves all color choices and elements of the plaza.
On-time completion of the project required Bulfon and his team to ensure paver symmetry in long, curving, and less-than-uniform lines. At first, the project was a bit of a puzzle, he reports. We knew when we started there would be challenges, and we spent the first two weeks just cutting the stones using every saw or machine we could think of, but it just didn’t work. We couldn’t get a straight line.
The difficulty with the project, as Bulfon explains it, is that square pavers had to be placed in long, curving lines that are not uniform. After some trial-and-error and much tinkering, Skanska created a walk-behind saw designed and used especially for this project. The saw was placed on a set of rails to guide the perfect cut and carefully shape each paver to its unique curve.
The plaza is basically two historical radius lines, neither of which complement the other, he says. The radius changes, and we needed to figure out a way to cut as we go. Every single paver was cut, and nothing was done in a straight line. Sometimes, it was a matter of just shaving the paver; and sometimes, we were cutting 2_ inches on either side of a single paver. It took us two weeks just to figure out how we were going to solve this problem.
Because of the time delay in getting started, Skanska commissioned three of the specially built saws to make up the time difference on the $3.7 million renovation. Work began on April 14, 2008, the day after the city’s Cherry Blossom Festival ended. Once we really got moving, our placement rate was about five lengths per day, with each length Û one time across the plaza Û being anywhere from 40 to 60 feet. That’s 11-hour days, six days a week, Bulfon observes.
The renovation included laying the pavers in a dry pack sand and cement mixture. First, a concrete slab was poured over an existing subbase, then a dampened mixture of sand and cement was used. Each paver was laid one by one.
From it’s Rockville, Md., offices, Skanska has done quite a bit of paver work in the D.C.-Metro area, including most recently a naval base for the Missile Defense Agency in Dahlgren, Va. Meanwhile, a formal Lincoln Memorial rededication is scheduled for May 30.
BUCKINGHAM FOUNTAIN, CHICAGO
The Chicago Park District began installing Unilock permeable interlocking concrete pavers in late October, as part of the Buckingham Fountain Renovation Project. Comprising 235,000 square feet Û or 5.4 acres Û of permeable pavers, the famous fountain will boast the largest decorative permeable paving area in the U.S. The pavers will maintain the fountain’s historic character, as they ensure Americans with Disabilities Act (ADA) compliance.
The Chicago Park District approved Eco-Priora Coral Gem pavers for Buckingham Fountain primarily because the product meets three critical requirements: the pavers satisfy federal guidelines for ADA accessibility requirements; they match the original fountain paving color and appearance, thus maintaining its historic character; and, they satisfy stormwater management requirements without the need for additional water storage in surface basins or underground chambers.
Additionally, permeable pavers have proven durability, minimal maintenance, ready availability, invisible repairs, and they demonstrate best management practices regarding sustainability and environmental sensitivity, says Michael Fus, Preservation Architect for the Park District.
Unilock matched the previous pebble surface with pink granite concrete pavers. The Eco-Priora pavers make for a much smoother surface and provide a similar look surrounding Buckingham Fountain. Landscape restoration around the perimeter will further enhance it. Phase 2 of the renovation will include improvements to the fountain itself, implemented in 2009 and 2010.
Peak placement rates often ran 6,000-7,000 sq. ft. of pavers per day, although when snow came to Chicago in early December, the rate slowed to about 5,000 sq. ft. per week.
With this project, the Buckingham Fountain area will meet the Chicago Department of Water Management’s new 2008 ordinance for stormwater detention requirements. Permeable pavers are included in the ordinance as a best management practice and are more durable than other materials, with a lower life-cycle cost. Pavers can support heavier loads from large vehicles that use the area for events such as Lollapalooza and the Taste of Chicago.
Unilock has seen an increased demand for permeable pavers in the last six years, because of their environmental benefits and efficiencies with stormwater runoff. Currently, there are more than 3 million sq. ft., or 68.8 acres, of permeable pavers in the Chicagoland area, mostly in parking lots.
Permeable pavers allow water to infiltrate below the paving surface and detain stormwater runoff until after a peak storm surge. Eventually, the majority of runoff will infiltrate naturally into the subsurface area, reducing or eliminating the amount of stormwater entering a municipal system. The use of permeable pavers is a recommended best management practice by the U.S. Environmental Protection Agency and a recommended construction practice under Low Impact Development and LEED guidelines. The most significant environmental advantage of permeable pavers over traditional paving surfaces is that they make rainwater valuable, storable and usable.