The Resilience of Skyscrapers: Exploring the Impact of Extreme Floods

Imagine a 37-meter wave going through a major city like New York City. How would the iconic skyscrapers fare against such a formidable challenge? In reality, the structural integrity of these buildings would ensure theirstanding. This article delves into the resilience of skyscrapers during extreme flood events, focusing on practical examples and expert insights.

Understanding Skyscrapers and Flood Resilience

37 meters (or approximately 121 feet) translates to a height of between 11 to 12 stories, a typical range for apartment houses and low-rise commercial buildings. Early New York skyscrapers, such as the Flatiron Building and the MetLife Tower, possess steel frames surrounded by masonry. Later constructions retain the same steel frame structure, abandoning real masonry after the 1920s for all types of buildings. Consequently, the steel frames provide sufficient structural support to withstand catastrophic waves and floods.

Factors Influencing Skyscraper Resilience

While the primary structural integrity of the buildings themselves would remain intact, prolonged flooding could still result in significant damage to internal fittings and electrical systems. However, the buildings themselves would stand strong.

The critical factor resides in the potential for water to infiltrate structural elements. If the water saturates the steel girders and remains untreated, corrosion could weaken the frames, leading to potential collapse. This scenario is akin to the World Trade Center towers where the absence of water damage prevented immediate collapse. Flooding that lasts for months or years greatly increases the risk of corrosion and associated structural weakening.

Case Study: Corrosion in One of New York's Iconic Buildings

One of the longest-standing examples of the vulnerability of historical buildings to water damage is the New York City church built during the period of 1911-1913. This steel-framed structure stands as a landmark and a US national historic place, yet required extensive maintenance. Regular inspections in the early 2000s revealed significant corrosion of the limestone surfaces around the bell towers. Engineers identified severe weakening of the underlying steel, though it did not immediately threaten collapse. A fundraising campaign ensued, lasting nearly ten years to secure funding and navigate bureaucratic hurdles to commence critical repairs. The restoration entailed overhauled steel frames and water-resistant cladding, reflecting meticulous attention to preservation and safety.

Contemporary Measures: Lessons from Hurricane Sandy

Over the past decade, much has been learned from extreme weather events, notably Hurricane Sandy in 2012. This hurricane prompted significant hardening of buildings in flood-prone areas of Manhattan, including flood-proofing of basements and lower stories. New constructions now incorporate flood resilience as a design feature, enhancing overall safety margins. Interestingly, during Hurricane Sandy, no buildings in Manhattan collapsed, not even the low-rise structures. However, the situation was quite different for Staten Island, Brooklyn, and Queens, where small and two-story homes suffered significant damage.

Conclusion

Skyscrapers exhibit remarkable resilience against extreme flood events, thanks to their robust steel frame structures. Nonetheless, the long-term preservation of these buildings requires ongoing vigilance and adaptation to mitigate the risk of water damage. Understanding these factors contributes to both the maintenance of historical landmarks and the contemporary design of resilient, modern buildings.

Keywords

Skyscraper resilience, Extreme flood impacts, Building maintenance