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There may not be many places in the Town of Blacksburg where one can drive this summer without seeing a tower crane slicing the skyline. There’s a real shock and awe vibe, with one on Virginia Tech campus and another on N. Main St., half a block from Ace Hardware.
Indispensable in the construction of many multi-story buildings, tower cranes are the backbone of vertical construction. They are exceptionally stable with very large lifting capacities. Their height can be adjusted as a building gets taller by adding mast sections, making it useful throughout the construction process.
The loads – tons to dozens of tons — are as impressive as the precision with which they can be set on the structure. Their extensive reach allows the building to move along much faster than manual labor with smaller equipment on the ground trying to hoist materials upward. In the 1970s, the cranes switched from hydraulic power to electric, making them much more quiet. Watching tons of material move up, down and sideways is almost mesmerizing for the silent, smooth, accurate placement.
Safety is a critical aspect. The towers are manufactured, installed and maintained to strict engineering and regulation standards. Operators must be schooled, certified and expert in understanding load moment indicators, limit switches, joy sticks, computer systems and wind speed monitors, among other things.
These cranes are hammerhead models which feature a fixed, horizontal jib and a trolley assembly that travels the length of the jib to position the hook. The pulley system is in place to move the hook and load up and down safely, evenly, correctly and almost silently.
German inventor Hans Liebherr invented this style of tower crane in 1949 to assist with post-World War II rebuilding efforts. More than 75 years later, his design has become a vital component of the construction industry for efficiency, productivity, precision and safety.
Without continual growth and progress, such words as improvement, achievement, and success have no meaning. — Benjamin Franklin
Text by Joanne M. Anderson
Photos by Jon Fleming
Photos by Jon Fleming
