Manhattan Skyscraper's Hidden Safety Crisis Uncovered by Architecture Student

Manhattan Skyscraper's Hidden Safety Crisis Uncovered by Architecture Student

In 1978, Diana Hartley was writing her undergraduate architecture thesis when she made a shocking discovery. Her paper focused on the city corp center, a skyscraper in Midtown Manhattan. And after weeks pouring over the building's plans, she'd stumbled on a potentially deadly mistake, an oversight that threatened to topple the 59-story tower into one of New York City's most densely populated districts.

Key Takeaways

• Architecture student Diana Hartley discovered a critical safety flaw in the City Corp Center skyscraper.
• The building's unique design using stilts to support a church led to unforeseen wind vulnerability.
• Secret reinforcement work was conducted to prevent a potential disaster.

The new skyscraper had to be built on columns supporting it like stilts. Using stilts on a building's corners wasn't unheard of, but because the church stood at the corner of the block, these stil'ts had to be placed at the center of each side. While this novel design worried some of the building's backers, chief structural engineer, William Lameshury, took numerous precautions to ensure the building's stability. The outside would consist of V-shaped chevrons, forming a strong exoskeleton to support the skyscraper. This external structure also made the building much lighter, meaning there'd be less weight to support overall. This design did leave the building vulnerable to strong winds, but Lameshury had another state of the art solution, a tuned mass damper.

"With these structures in place, calculations showed that each side of the building could withstand powerful winds, and with all safety issues resolved, the building opened for business in 1977." - William Lameshury

This 400-ton counterweight was controlled by computerized sensors designed to counteract any swaying. With these structures in place, calculations showed that each side of the building could withstand powerful winds, and with all safety issues resolved, the building opened for business in 1977. But when Hartley was studying the tower a year later, she noticed something odd. It was true that each face of the building could endure powerful winds, and since a building's broad sides catch the most wind, these would typically be the strongest winds a building encounters. However, the tower's unique base meant that winds blowing on the building's corners were actually the bigger threat, and since traditional designs didn't warrant safety calculations

for corner winds, it seemed to heartily that the threat had gone unaccounted for.

When Hartley contacted Lameshury's firm about the issue, they assured her the building was strong enough to handle these winds. But checking the plans again, Lameshury noticed an alarming detail. A change, approved without his knowledge, had replaced the exoskeletons welded joints with cheaper and weaker bolted joints. This alone wasn't enough to topple the tower thanks to the mass damper, but if a storm knocked out the building's power, it would deactivate the counterweight sensors, leaving the building vulnerable to winds of just 112 kilometers per hour. Given available weather data, a storm this strong had a one-in-sixteen chance of hitting New York city every single year.

Lameshury never told Hartley what she'd uncovered. In fact, everything he did

next was top secret. After filling in the architects and executives at CityCorp, Lameshury's team worked with city officials to craft a confidential plan. Without warning the residents, construction crews began a string of nighttime shifts to reinforce the bolted joints. This delicate work began in mid-August 1978 and was only halfway complete when Hurricane Ella approached the city in September. City officials and CityCorp executives planned an emergency evacuation for a 10-block radius, but at the last minute, the hurricane veered out to sea. These secret evacuation plans were never used and the reinforcements were completed just a month later.

Typically, it would have been

impossible for this covert construction to go unnoticed, but the press was occupied with a newspaper strike spanning the length of the reinforcement project. In fact, the public didn't learn how close they'd come to a disaster until decades later.