By Lionel Lemay, PE, SE, LEED AP. Executive Vice President, Structures and Sustainability, National Ready Mixed Concrete Association
James Bogdan, LEED AP, QEP. Senior Director, Sustainability Initiatives, National Ready Mixed Concrete Association
Tien Peng, Assoc AIA, LEED AP+, PMP. Vice President, Sustainability, Codes and Standards, National Ready Mixed Concrete Association
Credit: 1 LU/HSW
Course Number: ZG102019CS
Build with Strength, a coalition of the National Ready Mixed Concrete Association, educates the building and design communities and policymakers on the benefits of ready mixed concrete, and encourages its use as the building material of choice. No other material can replicate concrete’s advantages in terms of strength, durability, safety and ease of use.
Over the past several decades, there has been a continuous increase in human and economic loss from disaster events. The rise in disasters and their consequences is related to a rise in people’s vulnerability, induced by human development. However, examples of resiliency planning and more stringent building code requirements still lag. This article will offer a view on emerging risks and opportunities as human and economic losses from disasters increase, with the overarching goal of supporting and advancing resilience in future construction of buildings and critical infrastructure.
- Recognize the increased risks from natural hazards and how resilient construction can support long-term sustainability.
- Identify approaches to mitigate the effects of natural hazards.
- Underpin a community’s economic vitality and safety through natural hazard mitigation.
- Demonstrate the importance of incorporating resilient standards in construction.
For millions of people in the U.S., the consequences of natural disasters have become increasingly real, personal and devastating. According to the National Oceanic and Atmospheric Administration (NOAA), 2017 was the costliest year on record for natural disasters in the U.S., with a price tag of at least $306 billion.
Hurricane Harvey broke a rainfall record for a single tropical storm with more than 4 feet of rain in southeast Texas matching Hurricane Katrina as the costliest tropical cyclone on record. Puerto Rico is still mired in recovery after Hurricane Maria in 2017, and nearly 3,000 are estimated to have died in the storm and its aftermath.
Requests for federal disaster aid increased tenfold in 2017 compared to 2016, with 4.7 million people registering with the Federal Emergency Management Agency (FEMA). These once-rare events are becoming more common and costlier according to NOAA. Hurricane Harvey’s record flooding in Houston was the city’s third 500-year flood event in as many years. It’s time to rethink the way we build to meet the challenge of the next natural disaster.
CASE STUDY: Resilience to Hurricanes
While The Brickell was being designed, Miami was recovering from the impacts of Hurricane Wilma. Many high-rise buildings suffered extensive damage and were out of commission for extended periods in this hurricane-prone area. The developer was willing to increase construction costs to realize long-term operability of the building. The 35-story, 586,000-square-foot office tower was designed to withstand the force of large projectiles, wind speeds approaching 300 miles per hour and storm surge.
Integrating resilience was paramount and involved a reinforced concrete structural system that uses post-tensioned one-way slabs and beams, elevating portions of the ground floor above the floodplain, impact-resistant glazing systems, and multiple back-up generators to maintain business and continuity for tenants. It cost an extra 6 to 8 percent to implement these resiliency strategies which was immediately recouped with more competitive insurance rates and lower operating expenses that amounted to $1 million in electricity savings. Additionally, with global companies concerned with business continuity across many time zones, high-profile tenants leased space in The Brickell faster than other nearby Class A office space. The Brickell also was awarded LEED Gold certification.
According to Verisk Insurance Solutions, 4.5 million U.S. homes are at high or extreme risk of wildfire, with more than two million in California alone. According to Munich Re, a reinsurer, there have been $23.1 billion in losses to wildfires in the U.S. over the past five years. 2017 was by far the worst year with $17 billion losses and that number will likely continue to grow due to climate change which is creating warmer and drier conditions.
As we continue to build near fire prone areas, damages caused by wildfires will continue to increase. According to the Bloomberg Businessweek article Why Is California Rebuilding in Fire Country? Because You’re Paying for It, the 1964 Hanley Fire in Sonoma County destroyed 100 homes whereas the 2017 Tubbs Fire, which covered nearly the same area, destroyed more than 5,000 homes and killed 22 people. The Tubbs Fire was one of 131 across California in October of 2017. By the end of 2017, more than 1 million acres and 10,000 buildings had been destroyed.
What is most surprising is that instead of building back to higher standards after the devastating fires, California policymakers are issuing permits to rebuild without updating building codes and even exempting residents from zoning rules so they can build even larger homes. State officials are even mandating that insurance companies not raise insurance rates for people in fire-prone areas thus passing the cost onto homeowners elsewhere in California.
The state paid nearly $700 million in fire suppression in 2017 yet California Governor Jerry Brown suspended the fee homeowners in fire prone areas pay to offset the higher risk of wildfires. Although recent attention has been on California because of the major wildfires in 2017, there are wildfire risks in most states.
According to NFPA, there were 499,000 structure fires in 2017, causing 2,815 civilian deaths, 12,160 civilian injuries and $23 billion in damages. NFPA estimates 262,500 fires occurred in homes resulting in 2290 deaths, 7,470 injuries and $6.1 billion in damages, and 95,000 occurred in apartment buildings resulting in 340 deaths, 3,130 injuries and $1.6 billion in damages. Property damages from fires have been increasing over time.
As a result of relaxed building codes, developers have increased the use of combustible wood-frame construction for multifamily construction (apartments, condominiums, hotels, dormitories and long-term care facilities) resulting in a rash of fires across the country that are reducing these buildings to ashes, putting lives and communities at risk. The recent spate of fires in low- and mid-rise structures throughout the country is raising questions and concerns about the safety of wood-frame buildings of this size.
Not only are these wood-frame building fires total losses, but they often cause considerable damage to surrounding buildings and property. Communities and surrounding businesses often don’t survive. Not only must businesses and residents endure the disruption of construction of the original building, but then must endure further losses from business disruption and relocation while the new building is rebuilt after one of these devastating fire events.
Why are Disasters Costing More?
In the last several decades, population in the United States has increased and migrated toward the coasts, concentrating along the earthquake-wildfire-prone Pacific coast and the hurricane-prone Atlantic and Gulf coasts. Over 60% of the U.S. population lives within 50 miles of one of its coasts, including the Great Lakes. At the same time, wealth and the value of possessions have increased substantially.
For example, while California’s Los Angeles County accounts for only 2.5% and Florida’s Miami-Dade County accounts for only 14% of their respective states land area, they contain 30% of their state’s property value. These changes in concentration of population and property values are significant contributors to the increased human and property loss.
Disasters result not as much from the destructive agent itself but from the way in which communities are (or are not) prepared. Disasters happen when the natural systems are disrupted by human development. In fact, there is no such thing as a “natural” disaster in the sense that losses caused by a hazard event are greatly influenced by the degree to which society chooses to mitigate against the hazard. When a disaster occurs, lives, assets, products and crops are lost; livelihoods are cut off; economic growth is curtailed or sent into reverse. It is apparent that there needs to be significant shift in how we address natural disasters, moving away from the traditional focus on response and recovery toward emphasis on resiliency, that is, preventive actions to mitigate the effects of natural hazards.
What is Resilience?
There are several definitions of resilience. The Urban Land Institute (ULI) defines resilience as “the ability to prepare and plan for, absorb, recover from, and more successfully adapt to adverse events.” Basically, addressing changes in the environment, whether the changes are natural or man-made, requires actions to mitigate their negative effects and adapt to those changes.
If we identify resiliency, not solely as a state of preparedness for disaster (such as stocking up on food and water and having a plan in place to search and recover people in distress), but as a desired characteristic of a sustainable society, one that has more control of its basic human needs such as shelter, food, water, energy, communications and commerce, we can begin to see the relationship between resilience and sustainability.
For a community to be truly resilient it must address all human needs to some degree, but the very basic of all human needs is shelter. This means designing buildings to resist hazards such as flooding, wind, sea level rise or wildfires and other hazards. For a building to be sustainable, one must consider potential for future use and re-use and design for long service life with minimal maintenance costs.
Otherwise, the environmental, economic and societal burden of our built environment could be overwhelming. A building that requires frequent repair and maintenance or complete replacement after a disaster would result in unnecessary cost, from both private and public sources, and environmental burdens including energy, waste and emissions due to disposal, repair and replacement.
Of course, it’s one thing to describe resilience in generalities and another to design a building to mitigate natural disasters. There is significant guidance on reducing environmental impacts with green building codes and rating systems such as LEED, International Green Construction Code, Green Globes, among others. But the guidance for designing a building to adapt to and mitigate the effects of natural hazards are now only beginning to take shape.
Steps to Disaster Resilience
There are essentially two ways to approach disaster mitigation. There are voluntary programs where communities or building owners voluntarily reduce their risk of natural disaster through enhancements in structures, warning systems and education. The second approach is to install mandatory building requirements such that communities and building owners are obligated to design buildings and infrastructure to be more disaster resilient. The following are steps, combining both voluntary and mandatory mitigation strategies, to achieving disaster resilience:
- Adopt Updated Building Codes;
- Adopt High Performance Building Standards;
- Incentivize Disaster Resilient Construction;
- Build with Robust Materials.
1. Adopt Updated Building Codes
A common misconception is that a new code-compliant building in the U.S. will be resilient against considerable damage after a major hazard event. This is not always the case. The building code sets standards that guide design and construction of structures for minimum Life Safety, the first step towards resilience. However, maintaining the functionality of structures after a disaster is also important and building codes do not address functionality effectively. Sadly, special interests have convinced some state legislatures to reduce the stringency or limit the adoption of the latest building code.
To date Texas, Mississippi, Alabama and Delaware still do not have a statewide building code but pass the responsibility to the local jurisdictions to adopt the codes themselves. Florida, the state that faces more hurricanes than any other decided in 2017 to weaken its code adoption process. The North Carolina state legislature decided to placate homebuilders and update the building code only once every six years instead of every three. Builders claimed that weaker code makes it easier and cheaper to build in North Carolina, but new homes were ill-prepared for Hurricane Florence’s high winds, storm surge and rainfall. These states are not alone. Unchecked development remains a priority for powerful lobbyists, creating short-term economic gains for some while increasing risks for everyone else. As a result, the American public are footing the bail-out bill to the tune of $90 billion in disaster relief.
If we are to take people’s vulnerability seriously, we must deploy—and insist on—much greater emphasis in mandatory code adoption. While the design community can provide some of the expertise, their voices are not being effectively considered on the planning and policy level. The missing element is participation among practitioners, the development community, and policy makers interested in public safety over economic opportunism.
2. Adopt High Performance Building Standards
Buildings should not be a burden on their communities. They should have sufficient functionality after a hazard event and not place excessive demand on community resources such as emergency responders including fire, police and hospitals. Communities with disaster resilient buildings are more likely to be able to operate schools and businesses after a disaster. Stronger homes and buildings mean people will have places to live and work after a disaster. Less disruption for a community means robust commerce and consistent tax revenue.
Resilient buildings should consider a higher level of performance to protect property. Property protection means the building can withstand impacts and continue to provide its primary functions after a major disruptive event. The following are programs and standards aimed at incorporating resilient building techniques into construction to provide an optimum level of protection against a variety of natural hazards:
A. Enhanced Building Codes – Enhanced building codes can be developed and adopted through the building code appendices. The appendices are provided in the International Building Code (IBC) and the International Residential Code (IRC) to offer supplemental criteria to the provisions in the main chapters of the code.
After damaging windstorms in 2008, the Georgia Department of Community Affairs created the Disaster Resilient Building Construction (DRBC) appendices to the IBC and IRC, which form the basis for the Georgia State Building Code. The DRBC appendices offer an affordable, flexible, and simplified approach to improving resiliency at the local level. Local jurisdictions can adopt the complete appendices to improve building resiliency against flooding and high winds, or they can adopt select sections that apply to specific hazards in their geographic area.
Floods are the most frequent hazard resulting in disaster declarations. For those jurisdictions seeking to enhance their local floodplain management regulations, a compilation of flood resistant provisions is provided in Appendix G of the IBC. Like the Georgia DRBC appendices, the provisions contained in Appendix G are not mandatory unless specifically referenced in the adopting ordinance. The appendix helps minimize the expenditure of public money in many ways: flood control projects; the need for rescue and relief efforts; prolonged business interruption; damage to structures; and ultimately, protecting human life.
FORTIFIED Programs – The FORTIFIED for Safer Living and Safer Business are programs of the Insurance Institute for Business and Home Safety (IBHS). The program provides enhanced design criteria relative to code minimum and the necessary construction and inspection oversight to ensure high performing structures that are truly disaster resilient. The IBHS is a not-for-profit applied research and communications organization supported by the insurance industry.
USRC has a rating system for earthquakes and is working on other hazards. Source: USRC
USRC Building Rating System – The US Resiliency Council (USRC) is a national organization dedicated to improving the sustainability and resiliency of buildings during earthquakes and other natural hazards. The performance-based USRC Building Rating System assigns one to five stars along the dimensions of Safety, Damage expressed as repair cost and Recovery expressed as time to regain basic function. Certified buildings are expected to perform in a manner that will preserve life safety of the occupants, limit damage to repairable levels and allow functional recovery within a reasonable time period after a major seismic event.
CASE STUDY: Resilience to Earthquakes
Roseville City Hall Annex, Roseville, California
This four‐story, 82,000-square-foot office building houses critical city services such as IT, public safety communications and fire administration. Integrated project delivery (IPD) methods were employed to meet a short timetable for occupancy. Utilizing a Precast Hybrid Moment Frame (PHMF) gave the architect flexibility in the design and met a tight construction schedule. The concrete structure was erected in just 38 days which provided plenty of time to finish the project in seven months. Also important for the city was reassurance that during an earthquake critical operations and services would continue.
This project is the first to be rated and accredited by the USRC, achieving Platinum level certification. The structural system incorporates a high-performance moment-resisting frame that limits design level drifts to less than 1.25 percent. The system is designed to be self-centering after the seismic event eliminating residual drifts, limiting damage and providing for reduced recovery time. Other added benefits from an operational perspective include: lower long-term maintenance costs, superior sound isolation/exterior noise suppression and approximately 30% less energy consumption because of the building’s thermal mass.
REDi Rating System – The REDi (Resilience-based Earthquake Design Initiative) Rating System is a set of specific design performance criteria which aims to minimize building damage and promote contingency planning for utility disruption and other threats to functional recovery. The success of the resulting design in meeting specific monetary loss and recovery time is demonstrated by performing a modified FEMA P-58 loss assessment developed specifically for REDi.
RELi Standard – The RELi standard is a point-based system recently adopted by the US Green Building Council (USGBC). It includes many LEED-centric credits along with risk mitigation credits at the building and neighborhood scale. The intent is to provide greater adaptability and resilience to weather and other natural hazards in the built environment as a compliment to LEED. USGBC is currently refining RELi to provide a comprehensive list of resilient design criteria.
3. Incentivize Disaster Resilient Construction
According to Munich RE, insurance companies took a $135 billion hit from natural disasters experienced around the globe in 2017. Half of all losses were in the U.S., and North America representing 83 percent of all insured losses last year. The three successive Atlantic hurricanes – Harvey, Irma and Maria – cost major U.S. insurers at least $14.5 billion. This made it the costliest year ever for insurers.
Resilient buildings reduce the risks associated with property insurance. States can encourage building owners to build resilient structures by legislating insurance premium reductions to all policy-holders if they build to specific resilient design criteria. Alabama, Georgia, Mississippi and North Carolina have enacted such laws. These states now require insurers to lower the cost of property insurance for building to the IBHS FORTIFIED standard.
Hazard mitigation increases loan security for lending institutions and decreases business interruptions and improved bond ratings for property owners and communities. Therefore, other potential incentives should be encouraged:
- Building permit rebates;
- Property tax reductions;
- Accelerated local permitting and inspection procedures for resilient properties;
- Zoning benefits, e.g. density or height bonuses;
- More-favorable developer agreements for the construction of resilient properties;
- Revolving loan programs.
4. Build with Robust Materials.
The last step towards disaster resilience is to build with robust building materials. Some of the qualities of robust building materials include versatility, strength, wind and water resistance, seismic resistance, fire resistance, energy efficiency and durability. It is heartbreaking for a homeowner to survive a major earthquake, hurricane or tornado only to witness their home burn down in the aftermath. This was the case in Breezy Point, New York after Hurricane Sandy in 2012. Structural fires frequently occur after a natural disaster. Of all disasters, fire is by far the most common and the deadliest. The U.S. Fire Administration reports that every year, fire kills more Americans than all other natural disasters combined.
Increased fire resistance of building elements reduces the amount of damage to the building and its contents. Additional benefits are enhanced life safety, less demand on community resources, especially for emergency response, and facilities that are more readily adaptable for re-use.
As population grows in western states, we witness increased conflagrations from wildland-urban interfaces that devastate property, lives and economic growth. Regardless of location, the best approach to reducing fire losses can be accomplished by adopting Appendix D of the IBC which establishes Fire Districts where combustible construction is limited.
CASE STUDY: Concrete Apartment Building Survives Blast and Fire
In 2014, a massive natural gas explosion in East Harlem, New York City, destroyed two apartment buildings, vacated four neighboring properties, and shattered windows blocks away. Bricks, wood, and other debris landed on the adjacent elevated Metro railroad tracks, suspending service to and from Manhattan for most of the day. Nearby, buildings and households affected by the blast had to deal with the cost to remediate elevated levels of lead and asbestos. In total, the devastation caused 8 deaths, 70 injuries and displaced 100 families. Over 250 firefighters, paramedics and police officers responded. The local utility was responsible for $153.3 million damages, the highest payout for a gas safety incident in state history.
Through it all, the adjacent four-story concrete building stood strong. The New York Building Department engineer’s report said that amazingly, “there was no structural damage at all,” and the blast was located “inches, not feet” from the concrete walls, yet the building was in remarkably good-shape. Damage to the concrete building was caused by falling debris from the blast next door which penetrated the roof membrane resulting in water damage from firefighting efforts. The building, built using insulating concrete form walls, was reopened after repairs.
Chicago and New York City both employ Fire Districts to limit combustible construction within dense urban boundaries. The City of Sandy Springs, Georgia and other adjacent communities have enacted similar ordinances to preserve the health, safety, and welfare of its citizens.
Insulating Concrete Form System
Concrete building systems are especially suited to provide resistance to natural hazards. Leslie Chapman-Henderson, president of the Federal Alliance for Safe Homes, called concrete homes “the ideal” for withstanding extreme weather. 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.
Case Study: Tornadoes
Inman Intermediate School, Nixa, Missouri
Many Missouri school districts have spent years working to add safe rooms to their schools. Officials say it’s largely a result of the destruction of the May 2011 EF5 tornado that destroyed thousands of homes and businesses, dozens of churches, nearly a dozen school buildings and the loss of many lives. In fact, across the State there are now approximately 220 safe rooms in many types of buildings. One example is the new gymnasium at Inman Intermediate School that doubles as a tornado safe room. It’s basically a concrete fortress where the roof and walls are concrete.
Inman Intermediate School’s safe room was designed for a 250-mph wind speed or the equivalent of an EF5 tornado, meets specific flying-debris or missile impact criteria and are built five feet into the ground. As well, the facility has first aid equipment, restrooms, and backup power that can accommodate up to 1,200 people. FEMA grants covered 75 percent of the costs for the safe room. Nixa School District also has similar shelters at other schools including Mathews Elementary, Nixa Junior High School, and Nixa Senior High School. In total, the district can house 6,700 people in its safe rooms and they are open to the public.
Quantifying the Benefits of Resilient Construction
Building to a higher standard potentially adds cost and for an owner to accept the higher initial cost there must be convincing evidence of long term savings. There are several studies that attempt to quantify the benefits of resilient construction.
A. Urban Land Institute (ULI) – In their report Returns on Resilience: The Business Case, the Urban Land Institute ULI explores the economic benefits of resilient construction. The report presents ten detailed case studies that demonstrate cost savings from implementing resilient strategies. The study is based primarily on interviews with developers, property owners and their consultants to identify motivations to protect assets against climate-related threats, what resilience strategies were selected, the design and development processes, and ultimately the projects’ performance. Hazards addressed included inland flooding, drought, hurricane wind and storm surge. In all cases, the projects were able to demonstrate economic justification for spending more up front to design and build resilient structures.
CASE STUDY: Sea Level Rise
The Eddy, Boston, Massachusetts
For coastal cities, preparing for climate change impacts can be a daunting task. Despite threats of continuing sea level rise, development continues along our vulnerable coastlines. But developers of The Eddy, a 258-unit luxury apartment building along the waterfront in East Boston, understood those risks and designed the building to adapt to those threats. “Built to last” compared to “built to code” was a theme for The Eddy. For example, the high-rise was constructed nine inches higher than the previous building.
The electrical room was located on the first floor and the emergency generator on the roof as a buffer from storm surge, sea-level rise and flooding. It stores enough fuel on site in a secured location to support fire and safety operations for up to four days. Other resilient features included placing at-grade entrances at strategic locations and installing an 18-inch curb wall to prevent losses in case of a flood. The Eddy also realized immediate benefits. The insurance underwriter estimated the resilience strategies could reduce the potential flood-losses by 10 times compared to similar buildings without those features. Thus, the resilient design is creating real long-term savings.
B. NRMCA Insurance Cost Study – The National Ready Mixed Concrete Association (NRMCA) undertook a research study to understand if insurance companies offered lower insurance rates for structures built using non-combustible materials for both builder’s risk insurance and commercial property insurance. One of the main drivers behind the study was the enormous loss in buildings each year due to structure fires. According to a report Total Cost of Fire in the United States by the Fire Protection Research Foundation and the National Fire Protection Association, the total cost of fires in 2014 was $328.5 billion, equaling 1.9% of the U.S. Gross Domestic Product.
CASE STUDY: Concrete Walls Provide Fire Separations at Infill Site
Walker’s Landing consists of two buildings, six stories each, with four floors of residential over two floors of parking. The site of was restricted due to a 10-foot setback from a river, a bridge and two streets, making access for material storage and construction activities tight.
The project is located on an infill urban site requiring fire rated exterior walls. This is ideal for concrete walls since they provide more than enough fire rating at a significant cost savings over wood frame, especially when compared to many other projects in the city that had to use expensive fire treated wood. For Walker’s Landing, the developer used insulating concrete forms (ICFs) for the exterior fire separations.
In addition to fire resistance, the developer chose ICF walls and precast hollow-core floors for thermal efficiency and speed of construction. Construction projects are always on timelines and the developer has found that their install speed has increased significantly by using ICFs since they are fast and efficient to install.
The NRMCA study, titled Survey of Insurance Costs for Multifamily Buildings revealed that insurers are aware of the risks of building with combustible construction and the benefits of building with non-combustible construction.
According to the study, some agents suggested that the gap between rates for wood frame and concrete is likely to grow in the future and that a growing number of insurers are declining to serve as sole insurer for wood‐frame apartment buildings. Additionally, insurers of such buildings are increasingly requiring that the insured take extra measures to protect against fire loss.
C. National Institute of Building Sciences (NIBS) – NIBS undertook a study in 2017 to quantify the value of designing buildings to exceed the 2015 IBC or IRC for hazards including riverine flooding, hurricane surge, wind, earthquakes and wildfires with the objective of reducing losses. Results revealed that for every dollar spent on building above code, the amount of money saved ranged from $4 to $7 depending on the hazard.
The report suggests that architects and engineers can help clients understand the potential risks associated with a project and determine an owner’s risk tolerance and ability to mitigate those risks. Strategies to exceed minimum requirements of the 2015 building codes include:
- For flood resistance (to address riverine flooding and hurricane surge), build new buildings higher above base flood elevation than required by the 2015 IBC;
- For resistance to hurricane winds, build new homes to comply with the IBHS FORTIFIED Home Hurricane standards;
- For resistance to earthquakes, build new buildings stronger and stiffer than required by the 2015 IBC;
- For fire resistance in the wildland-urban interface, build new buildings to comply with the 2015 International Wildland-Urban Interface Code (IWUIC).
The NIBS report suggests that all major stakeholder including developers, lenders, tenants and communities benefit from resilient construction. The greatest benefits are afforded to building owners who don’t have to spend as much to repair and rebuild after a disaster, but there are other benefits also. Tenants benefit from having functioning shelter and places to work after a disaster, and the community benefits from reduced cost of disaster recovery both in terms of reduced loss of life and business continuity.
CASE STUDY: Storm Surge
The Sundberg Residence, Pass Christian, Mississippi
When Hurricane Katrina slammed into the coastal counties of Mississippi with sustained winds of 125 mph and a storm surge that reached 28 feet, the only house to survive along the beachfront of Pass Christian, Mississippi, was the Sundberg residence. Scott and Caroline Sundberg had just built their dream home along the Mississippi coast when the Hurricane hit. When the winds died down and the water retreated, the Sundberg home had survived the storm. All other homes on the beachfront were destroyed. Designed by the homeowner who is a structural engineer, they built their home using insulating concrete forms (ICFs) for the walls and cast-in-place concrete frame construction for the lower level, floors and roof precisely for this reason—to survive the devastating effects of a hurricane. The house is also built to withstand winds of between 180 and 200 mph.
The bottom of the first-floor structures is 25.4 feet above sea level. The ground level of the house is the carport with breakaway walls which performed as designed during Katrina. When they visited their new home after Katrina, the Sundbergs looked for cracking, spalling, and displacement, and they were relieved to find no signs of distress. In this case, the concrete added about 10 to 15 percent above the cost of conventional construction, but it proved to be a wise investment since using conventional methods of building would have led to total loss.
Life Cycle Cost of Hazard Resilience. Source: MIT Concrete Sustainability Hub.
D. MIT Break-Even Mitigation Percentage Tool – Too often, building developers make decisions about materials or building techniques to keep initial costs down. Although the resulting structures are built to code, those codes often fail to factor in the long-term costs or impacts on future owners and communities. Researchers at the MIT Concrete Sustainability Hub (CSHub) have developed a new tool to calculate the economic benefits of investing in more hazard-resistant structures in hurricane prone areas.
MIT’s Break-Even Mitigation Percentage (BEMP) tool evaluates the cost-effectiveness of mitigation for a building in a location by factoring in the expected damage a conventional building designed to code would endure over its lifetime. Then it compares that to the cost of a more resilient, enhanced building design to justify building to a higher standard. As would be expected, the greatest cost savings comes from building resilient buildings in counties directly on the Atlantic and Gulf coasts.
Resiliency planning offers communities, building owners and design professionals an opportunity to play a key role in determining the essential services and infrastructure needs that underpin economic vitality, health and safety of citizens, and support sustainability. National codes and standards are valuable, but the most effective method would be actively engaging in the local planning and code development process. By participating in code development so that building standards include hazard mitigation for fire safety, water access, energy conservation, and property protection, a community makes the conscious choice to invest in their own future.
Resilient building standards are not a panacea for all problems. Nevertheless, to subject our vulnerable population to the all too often, shortsighted political or economic decisions that trump safety considerations is unconscionable when the technology and economic returns of disaster resilience are well understood. Put simply, we all know that we must embrace change and build differently if we are to have a resilient future. High performance standards can help to make that happen. And, by promoting the development and adoption of advanced codes, standards and ratings systems, incentives and other measures that emphasize and encourage resilience, architects and engineers can lead by example.
In the end, no community can ever be completely safe from all hazards. Generally, it would be uneconomical to design commercial or residential buildings to survive a direct blow from a tornado with 300 mph wind speeds or magnitude 9.0 earthquake. But resilience promotes greater emphasis on what communities can do for themselves before a disaster hits, and how to strengthen their local capacities, rather than be dependent on our overwhelmed governmental agencies and aging infrastructure. Disasters are inevitable, but their consequences need not be.
Build with Strength, a coalition of the National Ready Mixed Concrete Association, educates the building and design communities and policymakers on the benefits of ready mixed concrete, and encourages its use as the building material of choice. No other material can replicate concrete’s advantages in terms of strength, durability, safety and ease of use.