Right now is an exciting time to be an engineer, said Northeastern University’s Jerome F. Hajjar, PE, PhD, at the start of his Thursday morning keynote presentation at NASCC: The Steel Conference. The industry is in an optimal position to be a guiding force for resilience and sustainability, but industry leaders must reframe how they think about both.
“This is a time when new materials, new design strategies, and new systems have the potential to revolutionize the way we think about our designs, our processes, and our profession,” Hajjar said.
Addressing a crowd of 1,700 Steel Conference participants, the SSRC Beedle Award recipient dove into the role of structural engineers in mitigating the inevitable impacts of climate change by challenging existing mindsets around sustainability and resilience.
When engineers design for resilience, arming the built environment against damage from natural disasters and other impacts of climate change, they are already designing sustainably--the two go hand in hand. Hajjar shared findings from more than a decade of research on resilience, explaining how we can apply fuse-based design to protect our buildings and bridges well into the future.
Hajjar discussed controlled rocking structural systems as one example of using easily replaceable inelastic fuses that prevent collapse but also enable quick reoccupancy after extreme seismic and wind events. This stands in contrast to traditional collapse-prevention approaches that focus exclusively on life-safety of occupants.
Similarly, employing energy-dissipating elastomeric bearings in bridge design limits force transfer from the foundation and protects bridges from collapse in a seismic event, Hajjar said. Over time, replacing these small fuses in a building or bridge’s substructure is more sustainable, adaptable, and cost-effective than replacing the entire building or bridge.
And often, cost is what scares clients away from choosing a sustainable project--they hear the word ‘sustainability’ and they see one big dollar sign.
Throughout his career, Hajjar has seen firsthand that when architects propose aesthetically beautiful designs, clients are all in--”but when they propose something that is sustainable, the calculator comes out and we start talking cost,” he said. “Technical innovation and leadership alone may not do the trick here.”
The solution, Hajjar said, is an industry-wide mindset shift whereby if a structure is not resilient, it feels unsafe, and if it’s not sustainable, it feels ugly.
“But let’s put a positive spin on it,” Hajjar concluded. “Let’s lead a culture shift--a shift in our mindset so that if our structure is resilient, it feels safe; if it is sustainable, it feels beautiful,” Hajjar said. “There’s hope for the future.”