Longevity, Safety Merge In Epic Dan Ryan Redo

by Elaine Schmidt

The three-year, $600-million-plus reconstruction project on the aging Dan Ryan Expressway on Chicago's South Side is the largest road rehabilitation project in the city's history.

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When it wraps up in 2007, the project will deliver a wider, safer, better-drained, more easily accessed and more durable expressway than the one it replaces.

Jacek Tyszkiewicz, engineer of project implementation for the Illinois Department of Transportation, the owning agency, said the famed expressway, which was built between 1961 and 1963, had grown increasingly unsafe. From just 1998 to 2000, 8,200 accidents occurred on the Dan Ryan, resulting in 27 fatalities and 1,800 injuries.

"In 1963 it handled 150,000 vehicles per day, but today it sees an average daily traffic of 320,000 vehicles," Tyszkiewicz said. "The original designers never even remotely thought of this volume of traffic."

Without a rebuild, the Ryan would worsen and become less safe than it is because it is the busiest in Chicago and one of the busiest in the nation. A combination of heavy traffic, aging, deteriorating pavement and poor drainage all contributed to the need for reconstruction.

"We have had a couple of resurfacings," Tyszkiewicz added. "We have tried to preserve the pavement a couple of times, and spot resurfacing was done as needed, but it finally got to the point that the reconstruction had to be done.

No matter when it's done it will mean an inconvenience to motorists, but postponing just means an escalation in prices."

Ryan Layer Cake

Tyszkiewicz said the pavement used in the early 1960s construction was designed to last for about 20 years.

"Typically, what is out there now is 12 in. of aggregate subgrade, then 10 to 12 in. of concrete, some reinforced and some not, and on top of that 5 in. of asphalt for 27 to 29 in. of total thickness," he said.

The new roadway is a 44-in.-thick layer-cake of paving materials, including 24 in. of aggregate subgrade, 6 in. of stabilized asphalt and 14 in. of reinforced concrete.

Thicker pavement is only half the recipe for roadway longevity in northern Illinois.

"In northern states you are always going to get the freeze/thaw cycles and the cracking problems they cause," Tyszkiewicz said. "If you get good drainage out there and manage the subgrade, you extend the life of the road."

Reducing surface puddles and flooding diminishes freeze/thaw damage, while keeping the subgrade relatively dry reduces the risk of blowups from underneath the concrete.

As of May, approximately 12,000 lin. ft. of drainage pipe had been removed from the expressway and was replaced by 40,000 lin. ft. of new pipe.

The combination of better drainage and thicker, more durable pavement should give the road a lifespan of about 30 years.

Resurfacing is being divided into three sectors, and work will be done only one section at a time: 31st Street to 57th Street, 57th to 71st Street and 71st to the Interstate 57 interchange.

A full interchange will be created at 47th Street with the addition of a northbound exit and a southbound entrance. Two access roads, 47th and 63rd streets, are also being reconstructed as part of the project.

Other elements include enhanced lighting and overhead message signs, higher barrier walls along the Chicago Transit Authority's Dan Ryan Red Line and landscaping.

A Ticking Clock

Patrick Goggin, operations manager for Chicago-based general contractor Walsh Construction Co., said the schedule is the paramount concern, given the enormous amount of work that has to be completed before the cold weather returns.

Walsh has taken control of the biggest variable in the project's timetable: deliveries of paving materials on the site.

Walsh located temporary crushing and concrete plants within blocks of the site. But that left the issue of getting trucks through the lanes of local traffic and into the closed express lanes >> with their loads.

The solution was found in the construction of six temporary ramps that allow trucks to move from the local lanes to bridges on which surface streets cross over the expressway.

"The temporary ramps are made of steel, crane mats and temporary barriers," Goggin said. "We installed them the first week of the job."

With 250 trucks in use per day, the ramps have more than served their purpose, Goggin added. Walsh has approximately 400 people onsite in a given day, subs included.

Road Map for Safety

New pavement and better drainage are only portions of the reconstruction's benefits.

An additional local lane in each direction is designed to allow motorists more space for merging into traffic and easing onto exit ramps and to improve the capacity of the road.

The exit- and on-ramps are also being redesigned to allow more graceful entrances into moving traffic and thus safer merging conditions.

Safety concerns extend to the project itself.

The site is overseen by the three full-time safety engineers Walsh has placed on the express lanes, as well as the additional full-time safety engineer covering entrance and exit ramp construction.

"We also do extensive safety training and hold daily and weekly safety meetings," Goggin said.

Barrier walls between the project and moving traffic are a safety buffer for the workers in the express lanes.

Tyszkiewicz said that Illinois State Police have a surveillance program that has helped keep traffic speed under control.

"The state police are taking photographs of speeders as they go by," he added. "If you are speeding in the construction zone, you will get a $375 ticket in the mail."

The first half-hour of the photo surveillance resulted in about 250 mailed citations, Tyszkiewicz said.

Another safety feature of the project is signage. Preparing motorists for what lies ahead is crucial to keeping traffic moving. Changeable message boards and static signs are both in use.

"We have portable changeable-message signs all over the place," Tyszkiewicz said.

In addition to warning motorists on the Dan Ryan and monitoring their reactions to traffic flow instructions, IDOT has also recommended various surface routes for motorists to take to alleviate some of the congestion on the expressway.

"We have spent quite a lot of time to try and get through to the local media to get the word out that we are closing lanes and that there will be a traffic impact," Tyszkiewicz said. "We wanted to make sure the public knew we were going to be closing the express lanes, that there would be an impact and what options they had to get around the city."

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