A 250t Grove mobile crane is using a custom 23-metre long, 23t capacity beam to lift 60 rebar cages on a highway project in Philadelphia, Pennsylvania.
The two-piece beam, supplied by the Caldwell Group, is being used to lift the large pier cap rebar cages, as required for concrete reinforcement during the rebuild of a 2.5-kilometre-long, 3-metre-wide overpass. The cages vary in weight, up to 20t, and length, up to 26 metres.
James J. Anderson Construction Co. (JJA), is delivering a scope of work for the Commonwealth of Pennsylvania, Department of Transportation (PennDOT) to build a two-mile elevated roadway, with ramps, drainage, and associated utilities and civil engineering works. JJA is using its Anderson-owned crane fleet.
Caldwell Director of Engineering Tom Eicher said the beam was designed, manufactured and built in two sections, due to the overall pick length required.
“It can be used both bolted together at its full length or in individual sections, if required,” he said.
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“The rebar cages require support at multiple points from the lifting beam by means of the lower rigging. Multiple lower rigging lugs allow riggers to distribute the weight of the cage to minimise cage deformation. This allows for proper control while handling the lifted load when positioning the rebar cage.”
Eicher said the upper rigging design arrangement helps further support the lifting beam. The lower lugs are sized for a minimum of three points used to pick up the load. There are 10 lower lug lift points on the full 23-metre-long assembly, while JJA can use any combination as needed to distribute the load as per their lift plans.
The two two-leg chain slings above the beam are rigged at angles to share the load when both sections of the lifting beam are bolted together and used as an assembly.
The synthetic slings above (connected to the crane’s hook) and beneath the beam (connected to the cages), are supplied by JJA. Sling angles were determined during the design process.
“The end hooks are able to attach rigging at a maximum of a 30-degree rigging angle,” Eicher said.
“Note that the end hooks are de-rated for that 30-degree angle if required to be used. Ultimately the span beyond 23 metres is dependent on the rigging length employed by JJA.”