"After September 11, 2001, developers, contractors, engineers and architects took a fresh look at composite structures — buildings with concrete cores and steel perimeters. The technique has rarely been used in New York City office towers, partly because ironworkers, long accustomed to being at the top of projects, were wary of working below cement workers without added overhead protection. But 3 World Trade Center, which is supposed to open in 2018, is being built this way. The concrete core of the 69-story skyscraper is rising ahead of the steel columns and beams around its perimeter, sometimes 20 or more floors ahead. It will act like a stiffening spine, helping stabilize the skyscraper against lateral forces, chiefly wind. @bryanthomasphoto photographed a worker at the top of 3 World Trade Center's concrete core last week." By nytimes on Instagram.
Posted on infosnack.