By: Jan R. Prusinski, PE
Concrete building systems are especially suited to provide resistance to natural hazards. Concrete has the necessary hardness and mass to resist the high winds and flying debris of tornadoes and hurricanes. Concrete is fire resistant and non-flammable, which means it can contain fires and will not contribute to the spreading of fire. Reinforced concrete framing systems can be designed to resist the most severe earthquakes without collapse. Concrete doesn’t rot or rust even if it is subject to flooding. (NRMCA, "Resilience Is the New Sustainability," InFocus, Spring 2012)
You would think that with all the emphasis on "green building" and LEED, that green rating systems and building codes, would be emphasizing building buildings that last for much longer periods (e.g. 100+ years, and could be easily re-purposed).
You would think that with the seemingly unending stream of "natural disasters" over the last several years (think: Katrina, Ike, Texas wildfires--in metro Houston--no less!), floods, North Texas tornados...and terrorist attacks), that green building rating systems and building codes would be developing provisions that ensure survivability of homes and buildings in reasonably predictable extreme events.
You would be wrong.
LEED and current building codes do not address these issues. Even the new International Green Construction Code (an "overlay code" to the widely adopted International Building Code) does not address survivability of homes and buildings after extreme (but again, somewhat predictable and definable) events. (See my previous blog - "'Functional Resilience' - What, Me Worry?")
The cement and concrete industry--notably the Portland Cement Association and the National Ready Mixed Concrete Association--have started initiatives to both inform/educate the public and industry stakeholders, and to change the building codes themselves. (Download fact sheet from PCA)
The NRMCA's InFocus magazine (Spring 2012) highlights the issue of functional resilience of structures (Peng, Lemay and Hansen, "Resilience Is the New Sustainability" - Part 1 and Part 2). It makes the point that "It doesn't make sense to design a modern building to meet LEED requirements that could be easily collapsed as a result of a hurricane or earthquake." All that great "green" technology--low flush toilets, roof gardens, solar and passive energy systems--would end up in a landfill. And not just for one building, but for a whole community/city.
Stephen Szoke, Director of Codes and Standards for PCA, noted in his presentation at the Green Matters Conference (download "Protecting Lives and Property: Makeing Green Buildings Resilient") in San Antonio in February that:
The NRMCA article made the important point that "Disasters are inevitable but their consequences need not be."
For instance, during Hurricane Ike on Texas' Bolivar Penninusla, 13 "FORTIFIED" homes survived a direct hit, including a 20 foot storm surge, as they were designed to withstand extreme wind and water damage. These were the only surviving structures in the area. (FORTIFIED is a voluntary program of the Insurance Institute for Business and Home Safety that incorporates design/construction techniques that provides optimum protection against certain natural hazards.)
Or consider that the only home to survive along the beachfront of Pass Christian, MS was the insulated concrete form home of Caroline Sundberg (download FEMA article), specifically built to withstand a hurricane (see photo).
The problem with not building resilient structures, with community-wide building codes, is that whole communities can disappear almost instantaneously. Lives are lost. Families become homeless, and possibly destitute. Communities are wrecked, maybe beyond resuscitation. Tax bases disappear. We all pay and many suffer terribly.
As building professionals and as citizens, we need to demand that "green construction codes" and "green rating systems" include resilience as a core tenet. Otherwise, how can we say that a building, home, or community is being built "sustainably" when we are not even constructing structures to sustain extreme events that have a high probability of occurring within a structure's lifetime.
"This blog was previously posted in the Cement Council of Texas' "Texas Cement and Concrete Blog" (now inactive) and was carried forward to the current blog ("Cementx Pavement Blog") as it contains content that may be of interest to the reader".
The Cementx Pavement Blog seeks to make pavement owners, engineers and contractors smarter about selecting, designing, constructing and maintaining pavements. New blog postings began February 1, 2017; however, we carried over pavement-related blog postings from our older blog, the "Texas Cement and Concrete Blog," which ran until December 2016.