Ep 1. Hell Tower NYC

Engineering Catastrophes season 2 episode 1, titled "Hell Tower NYC", takes a closer look at one of the most iconic buildings in New York City, the Citicorp Center. This episode investigates a relatively unknown secret behind the towering skyscraper – its rather peculiar design that almost led to a catastrophic failure.

In 1978, the 59-story Citicorp Center opened its doors to the public. This building, designed by architect Hugh Stubbins, is known for its distinctive diagrid structure, which allowed for a more open and airy floor plan. The center tower, which is slightly tilted off-center, is supported by four columns that diagonally connect with the façade's corners. The unique design meant that the building had a smaller footprint, allowing for a public space beneath the structure.

For the first time, the episode shows viewers how this design almost became a fatal flaw. The story dates back to the moment construction on the building began. Contractors who worked on the Citicorp Center noticed something strange about the building's design. A crucial steel plate that would have connected the building energy system's conduit from the mechanical spaces on the roof to the ground was missing.

As the documentary reveals, this missing plate, which was not in any of the blueprints, meant that the 200-ton tower atop the building could topple at any moment. An expert from the Massachusetts Institute of Technology identified this problem and warned the building's engineers. To fix the issue, the engineers had to come up with a solution quickly.

This episode reveals the engineering teams' journey to fix the Citicorp Center's 200-ton tower. They devised a fix from the ground up, which meant they had to lower the tower onto a temporary foundation to install the missing plate. Not only did they have to solve the immediate problem, they needed to do it fast. It was determined that if winds over 70 mph hit the building, they could cause a catastrophic failure.

"Engineering Catastrophes" takes viewers behind the scenes to witness the superhuman efforts that went into the fix. They show the engineering team's problem-solving abilities and attention to detail to rectify the problem before it became too late. The show documents the teams' challenges, from shutting down streets in some of the busiest areas in Manhattan to working together to devise a temporary foundation and lifting the tower to add the missing piece.

The episode also examines what would happen if the problem was never fixed. A catastrophic failure like this would have sent the tower crashing down on New York's elite Midtown area. Apart from the colossal financial implications, thousands of lives could have been lost.

"Hell Tower NYC" offers a unique and fascinating look into a design flaw that almost resulted in one of the country's worst catastrophes. It shows how intricate engineering and safety measures can have enormous impacts on people's lives. The construction and the secret fix on Citicorp Center became a landmark moment in U.S. engineering history, and this episode is a tribute to the engineers who saved the tower and the thousands of people living and working nearby.