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How Structures are Built to Resist Trauma

June 19, 2017

CEE Chair & Professor Jerome Hajjar spoke about how buildings are structurally designed to isolate fire damage following the London fire last week.


Source: News @ Northeastern

Early Wednesday morning, a high-rise apartment building in London was destroyed in a fire that the commissioner of the London Fire Brigade described by saying, “In my 29 years of being a firefighter, I have never, ever, seen anything of this scale.”

By late Wednesday, London’s Metropolitan Police had reported that 12 people died in the blaze, and at least 78 were injured. The fire comes on the heels of three deadly terrorist attacks, making it the fourth tragedy in the country in the past three months. Given the scale of the blaze, with the backdrop of uncertainty in the U.K., we asked two professors how structures—and people—can withstand trauma.

Jerome F. Hajjar, the CDM Smith Professor and chair of the Department of Civil and Environmental Engineering at Northeastern, noted that buildings are generally designed to isolate fire damage long enough to allow tenants to evacuate.

Daniel Aldrich, professor and director of the Security and Resilience Program, said that London’s strong resilience, combined with the coalescing that occurs after a tragedy, will help Londoners bounce back.

Q1. What’s in place to help secure the structural integrity of a building in the event of a fire?

Hajjar: In the U.S. and other regions such as the U.K., there are a number of fire regulations that need to be satisfied when you design a building in order to try to prevent the spread of fire. Depending on the nature of the building, this could relate to the types of materials used in the building, or whether fireproofing materials are required over the structural steel, for example.

The construction products that are used, including the exterior cladding system, are also expected to meet certain fire ratings so that it takes a long time before they lose their integrity or catch fire. That window is typically a couple hours.

While I can’t speak specifically to what happened in London, there have been several high-rise fires in Dubai, where engineers have called into question the cladding products that were used and whether the polymer materials between the sheets of metal skin were not sufficiently fire retardant.

Q2. At what point in the design process are fire reduction protocols taken into consideration?

Hajjar: Often, it’s something that’s thought about throughout the design process. There are a variety of decisions engineers and architects make along the way that could affect how fireproofing is done on the structure.

For example, in a building structure, they need to ensure that all key parts of the structure have a fire rating that would prevent the spread of fire and the loss of structural integrity for some period of time.

Q3. What sort of emotional toll might this fire have on the British?

Aldrich: With the uncertainty of the political atmosphere in England right now, people in the U.K. already had a background anxiousness. Certainly this fourth tragedy in a three-month span is making life difficult for all in the U.K. But, London has come through some tremendously tumultuous times in the past; there’s strong resilience in London. There’s also a strong sense of getting through challenges like this, and I think we’ll continue to see that.

Q4. Are Londoners equipped to bounce back from these tragedies?

Aldrich: Though it’s perhaps counterintuitive, getting through multiple traumatic events gives people an inoculation to it. People can use the lessons they’ve learned from the past to help bounce forward. Additionally, going through a tough time gives people a strong social cohesion—we saw this in the way people came together at Ariana Grande’s “One Love Manchester” concert. When you have bad things happen, people pull together.

London also has strong, active institutions, even if the future of their government is uncertain. If you can imagine a fire of similar scale happening somewhere that doesn’t have such strong institutions, it could really shut down the city.

Q5. How might Londoners bolster their own resilience?

Aldrich: They can make an active effort to reach out, to talk to people in their networks and say how they’re feeling.

Another big key is to engage in their normal activities as soon as possible. What’s most disruptive when emerging from a tragedy is not getting back to your routines—their first priority should be to re-establish normalcy as best they can.