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Published Jan 4, 2024
In Roads and Bridges Unique Picks

Video Case Study: Camping Cranes


 

Old world charm meets new crane technology

The Mohican River Recreational Area holds profound significance for the state of Ohio as a cherished natural treasure and a haven for outdoor enthusiasts. Nestled within the heart of the Buckeye State, this  scenic gem offers a diverse range of recreational activities, including hiking, camping, fishing, and canoeing, attracting visitors from near and far.

Beyond its natural splendor, the Mohican River Recreational Area also bolsters Ohio's economy by stimulating tourism, creating jobs, and generating revenue for local communities. Overall, this cherished destination epitomizes Ohio's commitment to preserving its natural heritage and fostering a sense of unity, adventure, and stewardship among its residents and its visitors.

But to enjoy the park, first you have to get  there. And this is where nature needs a helping hand, or, in this case, a well-traveled road and a bridge to connect the shores.

The Wally Road Scenic Byway is a winding vehicle route through rural Loudonville, Ohio, a village located between  Columbus and Cleveland near the heart of the Mohican River Recreational Area. A recent project replaced a nondescript  trestle-style bridge over the Mohican River with an eye-catching, old-fashioned, covered wooden bridge – with a modern twist.

 

Where it began

Deterioration of the 1993 bridge ultimately motivated the need for a replacement. The steel used then, which was designed so it would not require painting and other maintenance, absorbed moisture, eventually causing it to  deteriorate to a point necessitating plans for a replacement. This gave way to opportunity. The new bridge – a quaint-seeming  throwback, a wooden covered bridge – would better match the splendor of the surrounding park. But quaint didn’t mean delicate. This new bridge is a modern beast with a revised substructure design, allowing for a bold, 100-year-life-span projection.

It took two decidedly modern cranes from ALL Erection & Crane Rental, flagship yard of the ALL Family of Companies, to get construction started. 

This being 2023, the “wooden” bridge is actually made of a combination of wood and steel, in the form of Pratt trusses assembled on site. These trusses of triangle-shapes with diagonal supports sloping toward the center of the bridge were introduced in 1844 as an effective way to  cover long spans of 250 feet or more.

For Loudonville’s Wally Road bridge, spanning 300 feet over the Mohican River, two large Liebherr all-terrain (AT) cranes were needed to set the first two trusses. The massive marvels have capacities of 550 tons and 770 tons, and crane operators had to perform complex maneuvers to bring the assembled trusses from the ground to their final resting places on the bridge abutments. 

 

The lift days

The larger of the two cranes, the LTM 1650, was first to pick a truss and swing it over the Mohican River. Once it reached a 70-foot radius, it had to lower the truss back down, with one end on a temporary support and the other end hanging over the river. The LTM 1450, staged on the other side of the river, then attached to the floating end of the truss. The truss was now stable enough for the LTM 1650 to release the truss and pick it up from the other end. At that point, the two cranes executed the dual pick to set the truss in place. The process occurred twice over the course of the day.

Setting future trusses required only one crane. For the single-crane picks, ALL used a 770-ton Liebherr LTM 1650-8.1 all terrain crane with 171 feet of main boom in the T5Y configuration, meaning Y guying was added to boost lift capacity. On one action-packed workday, the 1650, set up on a flat bank of the river below, lifted two Pratt trusses, set a half-dozen 50-foot floor beams, and several roof trusses.

Liebherr’s VarioBallast® was key to setting so many large pieces so efficiently. It allows the ballast radius to be infinitely  adjusted using a hydraulic slewing mechanism. “The operator can constantly transfer and adjust the counterweights depending on the weights of each piece and the radius required for each pick,” said Rick Cope, project  superintendent for Kokosing. “Seeing what these large  specialty cranes are capable of is impressive.”

The Pratt trusses weighed 168,000 pounds and measured 160 feet long. For lifting, three spreader bars were hooked to the crane, and nine men handled tag lines attached to the ends of the truss. Once set in place, the trusses were temporarily braced before setting the next.

The bridge opened to vehicle traffic over Labor Day weekend, 2023.