Dual Grove GMK7550s lift historic relics for Smithsonian museum
By John Skelly09 July 2014
W. O. Grubb was recently tasked with a complex lift for the Smithsonian’s new National Museum of African American History and Culture. The company chose two Grove GMK7550s for a dual lift to ensure the project was completed with the best tools for the job.
The lifts took place immediately adjacent to the National Mall. The first lift was to place a nearly 50 USt railway car that was so large, it had to be put in place before construction of the museum could be completed around it.
The lift took place on Constitution Avenue, next to the National Mall and in view of the Washington Monument. The road was closed and the two Grove cranes moved in to set the shrink-wrapped railway car into a 60 foot deep construction pit. The two cranes were on opposite sides of the 80 foot railway car, which was rigged with two straps on each side with 10 foot spreader beams. The straps were connected to beams underneath the car to avoid damage from hooking to it directly. It was then lowered in place.
The GMK7550 is Grove’s largest all-terrain crane. It can lift up to 550 US tons and has a 197 foot Megaform boom. The crane features Megatrak suspension on a seven-axle carrier, a removable rear outrigger box, an Allison automatic transmission and a Twin-Lock boom pinning system. When rigged with an 82 foot to 259 foot luffing jib and inserts, the crane can achieve a maximum tip height of 430 feet.
The second lift involved placing a guard tower into the pit that was used in the 1930s at Angola, the Louisiana State Penitentiary, which was known as one of the worst in the country. A 17.5 US ton concrete tower and corrugated steel roof made up the tower that was lifted into the pit by a single Grove GMK7550.