High above New York City’s streets, ironworkers building the 70-story One Manhattan West tower are laboring inside of a six-story, 900-ton steel-mesh cocoon that hydraulically crawls up the sides of the building as they erect structural steel around the tower’s concrete core.
Once several floors’ worth of steel is in place, the cocoon retracts its walkways, activates its hydraulic cylinders and jacks itself up to the next tiers. Suspended from the building’s columns and driven by its own onboard generator, the cocoon can travel between floors without the aid of a crane or even stopping work on the site.