July 26 - Kraemer North America is replacing an 84-year-old truss bridge, the 2,482 ft (757 m)-long Savanna-Sabula Bridge near Savanna, Illinois, using a barge-mounted Manitowoc MLC300 equipped with VPC-MAX, hired from Dawes Rigging & Crane Rental (Dawes)
The Illinois Department of Transport hired the Plain, Wisconsin-based general construction company to construct the new bridge, which spans the Mississippi River between Savanna and the island community of Sabula, Iowa.
While planning the project, which involves the construction of two 958.5 ft (292 m)-long outer plate girder spans and a central 546 ft (166 m)-long tied-arch span, Kraemer realised that a barge-mounted crane solution would be necessary to access the lifts for the tied-arch span.
The company consulted with Dawes about a crane that could be mounted on the tight working quarters of a barge, whilst still providing high-capacity lifts to great heights for the bridge construction.
Where before contractors may have used Manitowoc Ringer or other cranes for a barge-mounted solution (due to the round Ringer shape that helps stabilise the crane and distribute the weight of the machine), Milwaukee-based Dawes suggested the newer model MLC300 crane that is able to automatically adjust its counterweight to provide greater stability for each lift, all from a smaller footprint than previous-generation cranes.
When the Manitowoc MLC300 crawler crane debuted with Variable Position Counterweight (VPC) and the VPC-MAX heavy lift attachment, one of its unique selling points was the crane's barge-lifting capabilities.
The reduced footprint and floating counterweight meant that it would be much more efficient for lifters to barge-mount a crawler crane, says Manitowoc.
"With the VPC, the MLC300 is always finding a new centre of gravity based on the load that's on the hook," said Patrick Shea, project manager for Kraemer.
"This crane has helped us to achieve almost zero list while working on the barge, keeping every lift level while minimising the barge's rotation. And the VPC saves space, too - most crawler cranes with the required length of boom would not have fitted on the barge in the first place."
The MLC300 was erected on a barge in the Mississippi River measuring 70 ft (21 m) by 195 ft (59 m) and was used to lift 69-tonne arch rib sections to a height of 165 ft (50 m) using 295 ft (90 m) of main boom, all from a 100 ft (30.5 m) radius.
To meet the lift radius and pick weight requirements on the job, Dawes' MLC300 had to be outfitted with its optional VPC-MAX heavy lift attachment, which enhances the crane's capacity and enables additional boom and jib length combinations.
Shea added: "Dawes provided the ideal crane for this work environment. The whole time we've been using the MLC300, we've seen the barge list by less than a degree, which is a testament to the stability that this crane provides and it's a big reason we're able to keep to our schedule."
Construction of the USD80 million Savanna-Sabula Bridge replacement began in March this year and is on schedule for completion in 2018. The new bridge will be 2,463 ft (751 m) in length and will meet modern day deck-width standards to improve the flow of two-lane traffic.
Dawes Rigging & Crane Rental operates four service yards in its home state of Wisconsin, providing service across the US Midwest to all types of contractors.
Variable Position Counterweight (VPC) technology enables the MLC300 to adjust its counterweight during each lift, which helps keep the barge stable while lifting.