Posted on July 3, 2019
Equipment Rented:
Telemetry Crane Scales
Chicago’s Congress Parkway Bridge
Rehabilitating and reconstructing a 60 year old bridge can sound pretty daunting, especially if it hasn’t experienced significant repairs since its creation. But that’s exactly what Walsh Construction had to do for the Congress Parkway Bascule Bridge in Chicago, Illinois.
The bridge was built in the 1950’s as part of the national highway development. While it had undergone minor repairs over the years, no major overhauls had ever been conducted. By 2010, its deteriorating condition prompted the Illinois Department of Transportation to enlist Collins Engineering, along with subcontractors Delgado Construction and Walsh Construction, to rehabilitate the four structural steel bascule spans of both the eastbound and westbound bridges. The project included a complete replacement of the decking system and the components responsible for opening the spans, ensuring they remained properly balanced to function safely and reliably.
During the reconstruction of the aging conduit, Walsh had to lift 112-foot bridge spans, secure them at a 70-degree angle, and then carefully lower them back down in a slow and controlled manner.
Walsh’s Project Manager, Joe Q., said there were additional challenges that presented themselves during the course of the two-year project:
“The real challenge was keeping traffic flowing during the rehabilitation. Since the Congress Parkway Bridge has separate bridges for eastbound and westbound traffic, we had to keep one side open while working on the other side. During the construction, we had to maintain boat traffic. During the summer, sailboats passed through twice a week, Wednesdays and Saturdays, so we had to ensure that the bridges could be lifted upwards to allow the boats to cross. Keeping the bridge balanced proved challenging, too. Every time we added a piece of steel to the bridge, the weight of a 10-pound piece of steel placed 100 feet away from the pivot arm had the same impact as a 1,000-pound piece placed just 10 feet away from the pivot arm on the opposite side. So, all these little things because of the nature of the project became exasperated and had to be taken into account and reviewed.”
All bascule bridges in Chicago share a common design: two long trusses with floor beams running across the roadway and grating placed between them. Over time, the open-grated decking has deteriorated, making steel replacement even more challenging.
An example of a bridge being moved with LGH’s Modular Spreader Beams.
To rehabilitate the bridge, Walsh installed an Orthotropic Deck System. While it remains a structural steel system with two truss arms and floor beams, it features lighter-weight steel and smaller floor beams, transferring the load into the decking itself. The system uses ½-inch flat metal plates and steel webbing underneath for structural support. As a closed system, it better protects against deterioration, preventing salt and chemicals from reaching the river or corroding the structural steel, ultimately making the bridge more durable and easier to maintain.
During the boating season, to allow vessels to pass, Walsh raised three of the four bridge leaves and locked them in an upright position while continuing rehabilitation work 220 feet above the ground. Using a scaffolding system and a crane, they meticulously replaced the steel piece by piece.
During the winter months, Walsh jacked the bridge spans in the opposite direction, preventing them from lifting upward. They raised the spans just a quarter of an inch using 500-ton jacks, shifting the weight onto a temporary support system to complete repairs that they couldn’t perform while the bridge was in the upright position.
To tackle this complex task, Walsh, through the former Delgado Erectors, consulted with LGH to determine the necessary equipment. Initially, they sought a winch capable of lowering the bridge in a slow and controlled manner, considering the bascule bridge’s teeter-totter mechanics. However, they advised that the desired winch operated at an extremely slow speed (7 feet per minute) and recommended a more efficient alternative. The chosen winch was faster but achieved the required slow descent by multi-parting the line through double-sheaved blocks. This mechanical advantage also reduced the need for a higher-capacity winch than originally anticipated.
Walsh ultimately rented two air-powered winches, securing them to a barge on the Chicago River, 150 feet below the bridge. Additionally, they utilized four high-tonnage double-sheaved blocks and telemetry crane scales to monitor the forces at play. Joe explained this process in more detail:
“When we completed most of the rehabilitation, we carefully lowered the bridge using the air winches, finishing the project with the spans down. Keeping the bridge balanced to ensure proper opening and closing was a constant challenge. We went through various jacks, setups, and configurations. The team at LGH didn’t just supply what we requested—they also provided additional equipment that made the job easier.”
The bridge’s rehabilitation in action.
“Finding a way to control the bridge lowering was a major achievement,” Joe said. “Each time we lowered a leaf, it was a success. When we needed to close the river, we coordinated with the Coast Guard weeks in advance to set time frames. Every time, the plan worked smoothly. We had backup plans in place, but fortunately, we never had to use them. Everything went off without a hitch, thanks to thorough preplanning and involving the right people, including LGH.”
The project, which began in 2010, officially wrapped up in 2012. The team ensured the project remained within budget and ultimately deemed it a success, despite weather-related delays affecting the schedule.
“I think everyone, including the state, would call it a victory,” Joe reflected. “I remember driving downtown 15 years ago, crossing over the bridge. There were temporary road plates with pieces of grating missing and holes forming. But now, with the new deck system and the rehabilitated bridge, it’s a solid structure. Maintenance issues are a thing of the past. I’m sure the city feels relieved to be done with those problems, I imagine traffic is much happier, too.”
Since completing this project, the City of Chicago has continued rehabilitating other bascule bridges, including Wells and Jackson Streets. In May 2015, the city awarded Walsh the contract for the Adams Street Bascule Bridge rehabilitation.
“I would absolutely work with LGH again,” Joe concluded. “The knowledge and expertise they brought to the table exceeded my expectations for a rental equipment company. They didn’t just supply what we requested; they recommended additional equipment to improve efficiency and explained why we needed it. LGH was more than a supplier; they were a true partner on this project.”
About Walsh Construction: Walsh Construction is a subsidiary of The Walsh Group, a 117-year old Chicago-based general contracting, construction management, and design-build firm. The Walsh Group is consistently listed as one of the nation’s top 15 contractors according to Engineering News-Record (ENR). The firm has experience with a wide variety of building, civil, and transportation sectors and maintains regional offices across North America.
About LGH: LGH is North America’s largest single organization devoted exclusively to the provision of lifting and moving equipment for rent. LGH holds the most comprehensive inventory for hoisting, rigging, jacking, pulling, material handling, and safety equipment. With over 80,000 pieces, discover your next project solution at RentLGH.com.
