From the ENR Archives: August 15, 1935
Cover from ENR Archives
This 1935 cover image shows a tower under construction for New York City’s Triborough Bridge (now known as the RFK Bridge), a suspension bridge with a main span of 1,380 ft, connecting Queens County with Wards Island.
It marked the first use of a guy derrick set on structural steel staging to perform this task. The 20-ft x 20-ft staging tower rested on the pier, and was built up over 200 ft in stages as steel erection continued.
The platform for the guy derrick at the top of the staging featured outrigger trusses extending 38 ft front and rear to hold the guy cables. The erecting derrick had a 106 ft mast and 94 ft boom, with a lifting capacity of 75 tons.
The derrick was kept busy, first erecting the Queens tower to roadway level, then dismantled and reassembled on the Wards Island side to achieve the same result, and then returned to Queens, by which time the Queens tower steel had been riveted.
Once it was used to top off the 270-ft tall Queens tower it was then dismantled and reassembled on Wards Island for completion of that tower. This kept the steel erection and riveting work separate, improving safety for work crews.
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