Engineered Rigging’s unique Cantilever Segmental Bridge Lift helped speed construction of the new 6,236-foot Cline Avenue Bridge in East Chicago, Indiana. The bridge straddles the Indiana Harbor and Ship Canal, a critical commercial shipping lane. Blocking this vital ship- ping passage with a massive construction crane traditionally used in bridge replacements was out of the question. Engineered Rigging’s new lift system enabled crews to move 19 concrete bridge segments, each weighing 75 tons, in just 16 days — all while keeping a com- mercial waterway open. Prior to its closure in 2009, the Cline Avenue Bridge was a popular route for 35,000 vehicles a day. Located less than 10 miles from the Indiana-Illinois border, the bridge will be heavily used by the signifi- cant interstate truck traffic traveling on nearby I-90, I-80, and I-94. “We were able to leverage our knowledge of strand jacks, skidding and tensioning to design and build a safe, economical lifting solution that also allowed commercial cargo vessels to continue using the canal,” explained Engineered Rigging President, Christopher Cox, P.E. Strand Jacks Perform the Heavy Lifting The Cantilever Segmental Bridge Lift features four strand jacks, each with a lifting capacity of 17 to 1,405 tons. The strand jacks act like linear winches. Each features a bundle of steel cables or strands that are guided through a hydraulic cylinder. Above and below the cylinder are anchor systems with wedges that grip the strand bundle. By strok- ing the cylinder in and out while the grips are engaged in the anchors, a lifting or lowering movement is achieved. Diesel or electric hydrau- lic packs supply the power. Used together, the strand jacks allow for precise, synchronous lifting. Engineered Rigging can simultaneously operate up to 60 strand jacks via computerized controls to lift very large loads. “Because of their compact footprint, strand jacks are ideal for use at construction sites — such as the Cline Avenue Bridge — that cannot accommodate a crane,” explained Cox. “In addition, a single operator can remotely control the strand jacks, which improves safety on site,” he added. Floating Barge Positions Bridge Segments Engineered Rigging’s Cantilever Segmental Bridge Lift attached to the bridge’s edge and extended horizontally over the water, with strands hanging below the platform. Crews then positioned each 75-ton con- crete segment on a small barge below the lift. Engineered Rigging Debuts Cantilever Segmental Bridge Lift On Indiana’s Cline Avenue Bridge By John Kuka
This cantilevered design enabled Engineered Rigging to lift each span thus enabling crews to secure it in place over the waterway. Once secured, Engineered Rigging repositioned the Cantilever Segmental Bridge Lift to the newly installed span so that the next concrete section could be hoisted into position. The configuration for this project supported a lifting speed of 60 feet per hour. “Once positioned, it took only 2 hours to lift a single seg- ment” said Cox. Skid Track Slides Lift into Position After each lift, Engineered Rigging’s onsite team had to reposition the system. It used specially designed half pieces of skid track, which matched the geometry of the bridge. This approach enabled the track to go down without delay. The team then used a split flow pump to operate the skidding system, which moved the Cantilever Segmental Bridge Lift into position for the next lift. The split flow pump also powered the side shift hydraulic cylinders used to position the concrete span side to side when aligning with pre- viously installed segment. The pump also operated the main long stroke cylinders, which pushed the platform out on the cantilever beams and pulled the segment into place longitudinally after it was lifted and but- tered with epoxy. All of the systems were critical to aligning the new bridge span along the X and Y axes and used in conjunction with strand jacks in the Z axis. “The hydraulic cylinders and split flow pump enabled us to easily ori- ent the bridge segments so that we could lock them into place with post tensioning equipment,” Cox explained. Overcoming Obstacles Engineered Rigging’s team faced several unique challenges when designing, fabricating and operating the lift. First, the engineers had to factor in Mother Nature. Autumn weather along the shores of Lake Michigan can be extremely windy and cold. “We designed system to work in temperatures below freezing and in winds that matched the capability of the crane onsite,” explained Cox. Engineered Rigging’s Cantilever Segmental Bridge Lift features four strand jacks, each with a lifting capacity of 17 to 1,405 tons. Used together, the strand jacks allow for precise, synchronous lifting.
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