Sustainable Building Design, Resiliency, and Precast Concrete
“Disaster resilience is a national imperative.” -National Academies of Sciences, Engineering, Medicine
Tis the season for storms. Hurricanes. Tornadoes. Strong winds. Extreme flooding. According to the National Oceanic and Atmospheric Administration (NOAA), in 2020, there were 22 separate weather and climate disaster events with losses exceeding $1 billion each across the United States. 2020 was the sixth consecutive year (2015-2020) in which 10-or-more billion-dollar weather and climate disaster events have impacted the United States and 2021 is shaping up to be just as bad. For millions of people in the U.S., the consequences of natural disasters have become increasingly real, personal, and devastating.
What is resilience and why is it important?
According to Evan Reis, SE, Executive Director, U.S. Resiliency Council, there are multiple components and dimensions of good building design relative to resilience. These three parts take into account social, physical infrastructure, and economic aspects since buildings are crucial to the ongoing business and social fabric of a community and its citizens’ lives.
- Social – people are protected and safe; keep casualties to a minimum.
- Physical infrastructure – buildings have to remain usable and functional after a disaster.
- Economic – cost in business losses and societal functions as a result of a disaster.
Resiliency metrics are safety, damage and functionality. To be resilient, a building must have all these aspects. Unfortunately, current building codes focus on safety, but not on damage and function. Most US buildings were constructed decades ago, before we learned lessons from major disasters. Even some structures built to modern building codes or green design targets may suffer significant damage or need to be demolished. Lives, livelihoods, our environment, and economic recovery are at stake. Current building codes are minimum requirements that aim to save lives, not to keep buildings usable after disasters. With natural and man-made disasters more commonplace, we need a broader definition of what meets code.
“Green” and Resilient Design are Two Sides of Sustainability
In his May 2020 webinar “The Role of Precast Concrete in Resilience-Based Design,” Evan Reis, SE, Executive Director, U.S. Resiliency Council contends that sustainability requires green and resilient design; there are two sides of sustainability. Green attributes regarding material selection that consider lower energy use, are made from renewable sources, produce less waste, and have a lower carbon footprint are important although LCA should take a broader definition and include preserving lives should a disaster occur, produce less debris in the face of destruction, have a longer service life, provide for faster economic recovery and help all stakeholders build stronger communities. He cites Superstorm Sandy as a case in point. LEED certified buildings were designed to have a low impact on the environment but not for the environment to have a low impact on them. The facts are devastating:
- Deaths were greater than 200 in the 7-county region
- Over 380,000 buildings in the tri-state area were damaged or destroyed
- Over $100B in estimated losses and economic impact
- Debris generated by the storm was greater than 10 million cubic yards. The result: trucks that took loads to landfills poured gas and diesel fumes into the air and new materials were transported to these sites to rebuild.
Designing for Destruction: Multi-Hazard Protection
In terms of building design and material selection, the elements of ductility, stiffness, and strength are important when evaluating for resiliency. A modern concrete building shows advantages in all these areas. Concrete design specific to earthquakes in terms of a precast hybrid moment frame system exhibits exceptional stiffness and essentially recenters itself. This design has been used in multiple USCR ratings for the highest level of performance for Safety, Damage and Recovery time. And these buildings rarely exceed 1 – 2 percent more in added cost to achieve this rating.
Relative to multi-hazard protection, precast concrete provides superior protection against severe weather events such as tornadoes, hurricanes, and floods. Precast concrete is often used in FEMA shelters as well as residential, institutional, public, government and other structures requiring extra protection from the elements. In terms of manmade disasters, precast has been tested to withstand extreme blast forces from explosive devices. Blast testing of precast insulated sandwich wall panels by the Air Force Research Laboratory in Panama City, Florida have demonstrated how precast meets the limits as defined by the U.S. Army Corp PDC-TR 06-08 Single Degree of Freedom Structural Response Limits for Anti-terrorism Design.
Given the gravity of manmade and natural hazard events of the last decade, designing buildings that not only offer resistance, but continue to function after a catastrophic event are significant challenges to the building industry. As we’ve learned through the pandemic, buildings are central to the lives of Americans where we live, work, learn, heal, and worship, helping nurture and sustain our communities, with socialization so key to our mental health and well-being. It’s paramount that we take into consideration the very real possibility of disaster impact and design buildings with resilience in mind.
For more on precast concrete resiliency and multi-hazard protection:
- Listen to the webinar recording “The Role of Precast Concrete in Resilience-Based Design” with Evan Reis, U.S. Resiliency Council
- View precast concrete’s impact performance testing, Impact Testing video.
- Download our blast resistance manual. MNL-141 PCI Blast-Resistant Design Manual.
- View precast concrete’s blast resistance – Precast Concrete Blast Test.
Read about award-winning post-Hurricane Sandy precast concrete projects, Nassau County Police 8th Precinct and the Statue of Liberty Museum
