Other than bridges, overpasses and the gentle rises of our golf courses, we really don’t have hills in Chicago. Until now, that is.

Maggie Daley Park, designed by Michael Van Valkenburgh Associates , brings all kinds of curves and slopes to the city’s New Eastside, home to some of the most exclusive real estate in the region.

Built atop the East Monroe Street Garage on the site of the former Daley Bicentennial Park, the 20-acre space adjoins the larger and more formal Millennium Park, which is also built above 2 municipal garages and a massive train yard. Together, the parks comprise the world’s largest green roof.

 

 

 

 

Curves every​​where

General contractor Walsh Construction called on Reyes Group of Markham, Illinois to place the retaining walls, light pads, walkways and other concrete features throughout the park. Prairie Material’s Yard 33 is providing all the concrete for the job.

“There are almost no straight lines in the park, making for some very interesting formwork,” says Reyes Job Superintendent Steve Basco, whose team worked through last year’s polar vortex and into the summer months so the park’s signature ice ribbon would be ready to open by winter 2014. The ribbon is just one of the playful features designed to delight visitors of all ages.

A ribbon for all seasons

A curving, ¼-mile loop that winds around a climbing wall and a grove of evergreens, the ice ribbon is made with standard 6-bag mix concrete – but the construction itself was anything but simple.

“The first step was to lay geo-textile fabric down over a 6-inch stone base,” explains Basco. “Then we installed a layer of blue foam with Number 5 rebar resting on 1 ½ -inch chairs.”

Next came a layer of 1-3/8 inch refrigerant tubes also resting on tightly spaced chairs. Welded wire reinforcement topped the tubes, riding just 1 inch below the surface of the 6-inch concrete slab.

The ribbon will challenge winter skaters with uphill and downhill sections, becoming a pleasant walkway in warmer months.

 

Lightweight hills

Creating slopes, valleys and play areas light enough to live above the parking garage called for advanced materials. “The high-density geofoam used for this project is amazingly strong, but a block measuring 4 feet by 8 feet by 40 inches weighs only 133 pounds,” says Basco.

More than 586 trailer loads of foam blocks were installed and topped with soil, turf and concrete over the past 11 months, Basco notes. Workers recycled old geofoam unearthed during demolition of Daley Bicentennial Park, reusing some of it to construct the new hills. Landscape crews began installing trees, shrubs and perennial plants last month.

 

 

Winding walks, built wit​h care

More than 200,000 square feet of exposed-aggregate walkways wind through the park’s landscape, constructed with 3,300 yards of Prairie’s pea-gravel-chip mix. The lightly pebbled surfaces add textural interest while meeting ADA requirements for wheeled access.

Walkway construction moves at a careful pace. “We’re placing about 33 yards per day with 3 scheduled deliveries,” Basco says. “After pouring, the concrete is bullfloated, sprayed with retardant and then hosed down with water to reveal the aggregate.”
Workers must manage runoff with care, since pH levels in the soil are already high, Basco notes.

Skaters welcome this winter, with grand opening next June

Park officials report that the project is currently on budget and scheduled to open on time in June 2015. The ice ribbon is expected to open for skaters by early December.

See Maggie Daley Park take shape in these webcam videos . Read more about the park’s playful, family-friendly features at the park website . And for more stories featuring our projects and partners across the Midwest, go to prairie.com .

 

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Maggie’s Legacy

Chicagoans loved Maggie Daley , wife of Mayor Richard M. Daley , who lost her life to cancer 3 years ago this month. During her 22 years as the city’s First Lady, Daley devoted herself to the well-being of children. The park that honors her memory features a children’s play garden complete with pyramid, ship and lighthouse structures and two 4-story climbing walls for all ages. Learn more about Chicago’s newest playscape at the park website .