Bridge replacement challenge for All Erection
By Euan Youdale06 August 2010
ALL Erection and Crane Rental used its 750 tonne capacity Manitowoc 18000 crawler crane on a bridge replacement project in Pennsylvania, USA.
The project involved replacing the Pohopoco Creek and Lehigh River Bridge structures on the Northeast Extension of the I-476 highway in Carbon County. During the course of the project, 175 beams measuring 102 to 168 foot (31 to 51 m) and weighing up to 120 US tons (109 tonnes) will be placed by the 18000.
Aaron Barnes, assistant resident engineer for the Lehigh River and Pohopoco Creek Bridge Replacement Project, said access and logistics made beam erection a real challenge on this project.
"We installed a construction causeway, where the majority of the picks are made, in the Pohopoco Creek valley," Barnes said. "Extremely steep slopes border the creek on both sides, and there is limited space on the causeway that ruled out picking the beams with two cranes. Because of these factors, we needed a crane that can lift beams of over 100 US tons (91 m) at a radius of 118 feet (36 m)."
The most challenging aspect of the job was the erection of beams for the longest spans on the Pohopoco Creek structures. There was very limited site access, so lifting contractor Cornell and Co. had to pick the beams from the right lane of the southbound mainline turnpike. Traffic lanes were closed while the 18000 set up on the construction causeway 120 foot (37 m) below the beam.
Except for the northernmost spans of the Pohopoco Bridge, the 18000 is picking the beams without assistance. The picks have to be done so the crane is close enough to handle the weight of the beam, but far enough away so the longest beam - 164 foot (50 m) - clears the crane's boom.
The crane had several different configurations during the project, but for the most challenging part, it worked with a 100 foot (30 m) mast, 160 foot (49 m) main boom and a 130 foot (40 m) luffing jib. It had 528,000 pounds (239 tonnes) of crane upper counterweight and 320,000 pounds (145 tonnes) of carbody counterweight.