Strong Buildings, Resilient Communities
Editor’s Note: HPB was published in August before a series of hurricanes, earthquakes, floods and wildfires struck around the world. Resiliency lessons learned from these natural disasters will be discussed in future issues.
Eleven months after residents of Orange Beach, Ala., returned to their homes to clean up the damage from Hurricane Ivan, they had to evacuate again to flee Hurricane Katrina’s wrath in 2005.
The back-to-back hurricanes damaged hundreds of thousands of homes, making it difficult for residents to resume their normal lives.
“When people can’t come back to their house, it affects that family, but it also affects the city as a whole. You never really recover fully until you can get those people back at home and back to work,” said Landon Smith, the City of Orange Beach’s chief building official and floodplain administrator.
Since the storms, Orange Beach mandates various resiliency requirements to fortify its buildings.
“Resiliency has got to be achieved at the community level. If you’ve got one resilient house over here and one over there, that’s not resilience. Even though you’ve got those families back, you still don’t have your community back,” he said.
Storms come fast and bring destruction often described as unprecedented and unbelievable.
During the last weekend in August, Hurricane Harvey stalled over Texas, dumping excessive rainfall amounts on southeast Texas and parts of Louisiana. Harvey’s floods turned roads into waterways as first responders used boats to rescue those in danger from the rising waters.
A Texas National Guardsman carries a resident from her home during flooding caused by Hurricane Harvey in Houston, Texas.
Army National Guard Lt. Zachary West
As HPB Magazine was going to press, some parts of the Houston metropolitan area had already seen more than 30 inches of rain, and the Weather Channel reported the city could be inundated with more rain in the week after Harvey made landfall.
The flood disaster could be the worst in American history, according to the Weather Channel.
Resilient buildings are strong enough to survive and operate during climate events—such as floods—and can adapt to deal with future threats. And, with scientists predicting stronger climatic events ahead, the value of resiliency is increasingly being recognized. For example, the U.S. Green Building Council awarded the first LEED Resilient Design Pilot Credit in October 2016.
Resiliency Varies by Location
Climatic and economic challenges vary city-by-city and region-by-region, so no one-size-fits-all resiliency plan exists that can protect cities, buildings and people against weather events.
More than half—52%—of Americans live near a coast along a body of water, according to the National Ocean Service. Historically, the more populated cities are situated along coasts internationally as well. These locations near waterways provided convenient access to trade routes, but the nearness to water and its climatic effects and storms also challenge the cities’ infrastructures. The threats vary by coast, challenging each city to find customized strategies and solutions.
When it comes to building resilient buildings and communities, cities, engineers, architects and other industry professionals throughout the world are developing and implementing strategies to strengthen their communities in hopes of surviving and thriving after the next storm.
Storms on the Gulf Coast.
Hurricanes Ivan and Katrina scratched away at Orange Beach’s already depleted beachfront—the city’s first line of defense.
Since the storms, Orange Beach has poured millions of dollars into building up the beachfront through beach nourishment practices and building up the dune system, Smith said.
If storms are ever strong enough to best Orange Beach’s developed beaches, the beachfront structures are now stronger and meet up-to-date building codes. The city’s flood hazards maps have also been stringently upgraded, he said.
Prior to Hurricane Ivan in 2004, Orange Beach was using older building codes. The city now uses the most current international codes with a coastal code supplement.
Hurricane Ivan destroyed buildings along Alabama’s Gulf Coast in 2004.
The FORTIFIED Home code-plus program is one supplement that emphasizes resilient roofing, and roof damage is one of the most common types of storm damage, Smith said.
“When you lose the roof, basically you have a bucket, and that bucket fills up with water,” he said.
Orange Beach construction projects are required to fulfill the Insurance Institute for Business & Home Safety’s FORTIFIED construction program requirements, which include using different building materials. For example, FORTIFIED requires projects to use a peel-and-stick material (as opposed to felt paper) that adheres to the roof deck or a type of synthetic underlayment that will not deteriorate or blow away when roof shingles are blown off during a storm. The standards also recommend high wind-grade shingles or metal roofs, Smith said.
Building scientist Joseph Lstiburek, Ph.D., P.Eng., Fellow ASHRAE, said buildings in hurricane-prone areas should not have vented roofs, which are likely to blow off during a storm. Unvented roofs are also energy efficient, saving energy throughout the year, he said.
“That’s because the mechanical systems are no longer outside in a hot, humid attic. They’re not located inside of a conditioned space. So we get a three-for-one here,” he said. “If we size our cooling equipment properly, the extra cost involved in constructing the roof in an unvented manner can be paid for by downsizing the size of the air-conditioning system, because I don’t need it to be as big anymore.”
Orange Beach allows for construction projects on the beachfront, but not past the coastal construction line, Smith said.
The city does not restrict what type of structure can be built on the beachfront as long as they are elevated to above the base flood elevation, according to Smith. Buildings built on the beach must be built on pilings that are required to be embedded to a certain depth depending on the building’s size and other factors. Single-family homes have to be built on pilings embedded about 25 ft into the ground, he said.
Orange Beach also requires impact-resistant windows or some type of shutter system, which Smith said can withstand strong winds better than haphazardly set up plywood.
“If we had the same storm today that we had in 2004, I think you would see a different outcome. I think you would be able to tell that these efforts that we’re making to make it more resilient work because you wouldn’t see as near the [amount of] damage as you saw back then,” he said.
Reinforcing to be Resilient
Earthquakes in Japan.
Three earthquakes a day send tremors throughout Japan, on average. Those tremors can make the lights go out for just a second or bring a whole city to its knees.
Volcanic activity is another threat, with more than half of the country’s 100 active volcanoes under close observation for eruption. If that were not enough, typhoons, tsunamis, floods and landslides also threaten the island nation.
“Since Japan is prone to many types of natural disasters, Japan has a long history of resilient building design, town planning and living,” said Kitaro Mizuide, Ph.D., P.Eng., Member ASHRAE, and general manager of the mechanical and electrical engineering design division for Nikken Sekkei Ltd.
Japan’s built industry first started resiliency planning after a 1923 earthquake struck the main island of Honshū including the Tokyo area, he said. Since then, Japan has rebuilt cities and introduced and revised seismic design requirements. Building codes dictate high-wind regions, seismic zones and structural design requirements.
The city of Osaka is no exception.
The Nippon Life Insurance Company Head Office-East Building in Osaka has seismic isolation engineering to guard against earthquake damage. One strategy includes using a seismic isolation joint for electric wires by lengthening the cable to separate the building from an earthquake’s effects, according to Mizuide.
The seismic-isolated structure in the Nippon’s East Building works by using a combination of oil dampers and rubber bearings at the building’s base, he said. Both devices achieve high seismic isolation effect.
Figuring out how to dissipate an earthquake’s energy is the key for resilient buildings, according to Lstiburek.
One technique is attaching brackets, braces and fasteners, and spraying the cavity with polyurethane foam, he said. The foam fights the earthquake’s energy and also saves energy for insulation and structural reasons, he said.
Other Japanese buildings are beginning to design for high-water flooding and tsunami disasters. For example, the YKK 80 building in Tokyo has generators, fuel inlets, fuel tanks, pumps and water storage to ensure operation in emergency conditions, he said. The Cool Radiant System, Inside and Out article in the Summer 2017 HPB Magazine discusses the YKK 80 Building.
Japan introduced business continuity planning (BCP)—a form of resilient design that includes providing for several days of temporary services such as electrical, water, shelter and food—in 2004, according to Miziude. Critical facilities such as hospitals, data centers and government services buildings always include BCP strategies, he said.
“Japanese planners think of resilience beyond the building. Of course, the first priority following any disaster is human health, safety and welfare, and building design for safe evacuation and shelter is a big part of that,” he said.
Rolling Hills, Rising Seas
Earthquakes and floods in California.
An earthquake roaring through a neighboring city in 1906 and a fire turning the city’s university and downtown to ash in 1923 have taught Berkeley, Calif., the challenges of disasters. The city lies along the San Francisco Bay and is threatened by potential perils such as: earthquakes, extreme storms, wind-driven fire and rising sea levels.
Berkeley is seeing more flooding, especially in one neighborhood near the bay, West Berkeley (also discussed on Page 6) where many of the city’s lower-income families live, said Timothy Burroughs, Berkeley’s chief resilience officer. West Berkeley’s location next to the rising bay invites possible challenges in the future, he said.
“As our challenges are interconnected, our solutions must also be in order to make Berkeley more resilient,” according to Burroughs.
Since 2004, Berkeley has seismically upgraded, strengthened or replaced buildings that are critical to the city and its public schools. More than 90% of the city’s 700 unreinforced masonry buildings have been retrofitted or demolished since 1991, according to Berkeley’s Local Hazard Mitigation Plan.
According to a 1996 survey, more than 400 soft-story buildings were located in Berkeley, and all soft-story buildings with five or more units have to be retrofitted by 2018. Automatic gas shut-off valves are installed in potential hazardous soft, weak or open front buildings—wood-framed multistory buildings with first floors that have large openings where a shear wall would normally be—that have gas piping.
To encourage building owners to strengthen their buildings, Berkeley has distributed more than $9 million through a tax rebate program that reduces the real estate transfer tax to building owners who perform seismic safety work, according to Berkeley’s Local Hazard Mitigation Plan.
Other resiliency strategies include stringent building codes supplemented by green building policies. All large commercial and new residential projects including multifamily developments must achieve a certain number of points on a Green Building Checklist that offers solutions such as rain screen wall systems, vegetative roofs and fire-resistant roofs. Berkeley requires new buildings and additions in its downtown area to receive LEED Gold certification or an equivalent.
The measures aim to reduce buildings’ energy and water use as part of Berkeley’s Climate Action Plan, which mandates the city must reduce its greenhouse gas emissions by 33% by 2020 and by 80% by 2050.
Berkeley is also planning for when disaster or a disruption does strike. The city is expected to complete a microgrid to provide clean backup power to the downtown area, Burroughs said. The microgrid would aggregate and share clean energy from solar and energy storage batteries and other distributed energy resources during peak periods. It would go into island mode when needed, he said.
The microgrid would advance energy reliability and improve public and private access to clean energy. It would also free up more critical functions of diesel—a traditional backup power source—in times of need such as for fuel for emergency vehicles, he said.
Built Near Water, Now Building on the Water
Flooding in the Netherlands.
The Nieuwe Maas river and a larger dike system along the Dutch coastline divide the home to Europe’s largest port, Rotterdam, Netherlands.
During World War II, the Germans destroyed a portion of the city, and now traditional Dutch buildings are sprinkled between modern skyscrapers and cube houses.
The city’s economy remains rooted in its port’s trade, and the city has redeveloped into a resilient city with plans to further fortify its various waterways and homes.
The Dutch have built communities and homes that float on the water, and their resiliency efforts also span to the city-level. For example, Rotterdam, the country’s second-largest city located off the North Sea, is expecting to face more rainfall, higher temperatures and rising water levels.
The Floating Pavilion was Rotterdam’s first floating building development, and now the city has floating homes and an experimental aqua dock. Three connected spheres are connected in the Floating Pavilion, which purifies its own toilet water that can be discharged safely into the surrounding surface water. Its HVAC system relies on solar energy and surface water.
The Floating Pavilion’s body is made of five slabs of expanded polystyrene or polystyrene foam with the thickest layer including a grid of concrete beams. Foil, which is lighter than glass, covers the dome and limits the pavilion’s need for a thick floating foundation.
The Floating Pavilion in Rotterdam was the city’s first floating structure. The city is facing threats of rising sea levels, and floating communities are gaining popularity.
Rotterdam has substantially increased its absorption capacity through principles of water retention, storage and disposal, according to the city’s resiliency strategy. The city has plans to continue this progress by using more green roofs, increasing public spaces’ water storage capacity and increasing public and private lands’ absorption capacities.
The city boasts 220,000 m2 (2.4 million ft2) of green roofs, and some include solar panels. The increase of greenery throughout the city helps with urban heat levels as plants provide shade and evaporation.
Rainwater collection is another strategy Rotterdam uses. Open public areas can store excess water including Benthem Square, also known as Water Square, that has three basins to collect rainwater. Rotterdam’s government and people have worked together to ensure 70% of the city’s privately owned land has better absorption capacity.
The older areas of Rotterdam located outside the flood dikes are the most susceptible to flooding, according to Rotterdam’s Resilience Strategy. Because of this threat, the Rotterdam Climate Initiative recommended raising structures in the areas and closing the storm surge barriers during storm tides to maintain outer-dike flood protection. Other methods include flood-proof buildings such as floating communities such as the Floating Pavilion.
For inner-dike protection, the initiative recommended reinforcing the primary dikes and closing them more frequently.
Another Storm, Another Coast
Storm surge in NYC.
Another hurricane caused one of the busiest cities in the world to abruptly stop like a taxi cab in rush hour traffic and go black. Hurricane Sandy shut down New York City—the largest city in the United States—in 2012.
Sandy’s storm surge did not reach the top of the city’s looming skyscrapers, but it did flood basements, lower levels and parts of the city’s public transportation infrastructure. The storm halted New York City’s ever-present traffic and the New York Stock Exchange.
A weather event had suppressed one of the world’s busiest cities.
Resiliency efforts and creating a stronger built environment had been on New Yorkers’ minds, but the city had not done enough by the time Sandy made landfall.
Russell Unger, LEED AP and executive director of the Urban Green Council, led the Building Resiliency Task Force in 2013, bringing together more than 200 of the top building designers and owners and policy makers who worked to create resiliency applications for the city’s buildings.
The task force’s work and a renewed urge to become more resilient spurred New York’s commercial and residential builders and designers to make some changes.
The Hugh L. Carey Tunnel in New York City flooded during Hurricane Sandy in October 2012. Sandy’s storm surge flooded New York City and surrounding areas causing massive blackouts and electrical issues.
Metropolitan Transportation Authority/Patrick Cashin
After Sandy, the built industry started creating more sidewalk barriers, implementing backup generators and adding more waterfront areas to serve as flood barriers, he said.
People also started to elevate HVAC and other electrical equipment to higher floors to protect them against flooding damage, according to Unger.
Other resiliency efforts focused on helping people when the power grid goes down.
For example, New York City law now requires multifamily buildings that are taller than five stories to add drinking water taps in common areas, Unger said. Water is fed by gravity in New York, and the system’s pressure will bring the water up five stories, he said. That way, people still have access to clean water during emergency situations.
“It seems like a small thing, but someday, we’ll have a multiday
power outage, and it’ll be hot. People will be using those and be glad for them,” he said.
Another resiliency project is being planned for a corridor in Brooklyn that houses three adjacent hospitals within 11 city blocks. Burns Engineering won a New York State Energy and Research Development Authority New York Prize Microgrid Stage 2 Award to design the Clarkson Avenue microgrid that is planned to provide energy to the hospitals during a power outage while reducing the load on the power grid throughout the year.
The microgrid is required to operate for as long as two weeks during a prolonged grid outage, and is going to have fuel cells running continuously, solar and battery storage operating intermittently and emergency generators helping to reduce peak loads. Cogeneration using microturbines is also possible, according to David Smith, director of energy services for Burns Engineering.
The hospitals will be electrically connected through an underground, directionally drilled microgrid circuit, so the system does not have to rely on utility wires during emergencies, David Smith said.
“During island mode, we’ll have a separate dedicated circuit that we’ll have designed and built that connects these facilities underground via directionally drilled duct banks,” he said.
One City, Multiple Threats
Fierce wind and temperature changes in Chicago.
The midwestern metropolis of Chicago is built off Lake Michigan with the Chicago River cutting through the city’s heart and diverting into the north and south branches to touch other parts
of the area.
Winds beat against Chicago’s skyscrapers throughout the year, and the changing of seasons brings a large range of temperatures.
The Windy City’s built industry has to take into account wind, flooding, freezing-thaw cycle, extreme heat and tornadoes, according to Megan Zack, AIA, LEED AP BD+C, principal and director of sustainability for Hartshorne Plunkard Architecture in Chicago.
“Designing for the unexpected is a requirement in the Midwest because we experience all sorts of weather,” she said.
On the city-level, the Tunnel and Reservoir Plan helps address Chicago’s flooding and water retention issues. The Plan uses tunnels and reservoirs to store storm water and sewage after heavy rainfalls to reduce combined sewer overflows, basement flooding and backflows into Lake Michigan, preventing polluting local waterways, according to Friends of the Chicago River.
Chicago is built on a marsh, and the city reversed the Chicago River in the early 1900s to prevent it from flowing into Lake Michigan and polluting it.
Individual buildings also provide for storm water management during a flood or heavy rainfall event.
Zack recommended including green roofs and storm water retention tanks on buildings to slow the water leaving the building site to not overwhelm the combined storm and sewer system. She also said buildings should be designed to move water away from the building, and landscape architects also use native landscaping that absorb water.
More than 500 green roofs, covering more than 5.5 million ft2, have been built within the city of Chicago, according to the city’s website.
A green roof sits on top of Chicago City Hall. The city has increased the number of green roofs to help storm water management.
Flickr user TonyTheTiger
Zack’s firm has also seen an increase of projects that incorporate durable rainscreen façades that act as a double-wall construction that creates an exterior layer. The façades keep the majority of the rain out of buildings and have an interior layer that insulates, prevents air leakage and carries the wind load, Zack said.
To protect buildings’ occupants against the extreme heat and cold variations, she said walls have become tighter to create comfortable interiors, which also helps manage the dew-point location. The two most important layers are continuous insulation and a proper air barrier.
Other resilient building methods in Chicago include passive design techniques that account for sun angles and provide intentional shading and natural ventilation for a comfortable environment during a power loss, according to Zack.
Chicago recently debuted its revised Sustainable Development Policy that affects any building that goes through the planned development process or receives any type of financial assistance from the city. Now, a building in Chicago has to implement at least one building certification or earn a certain number of points based on several options that include:
- Exceeding the energy code by 5% to 40%;
- Having on-site renewable energy;
- Exceeding the storm water ordinance by 25% or 50%; and
- Having 100-year detention for lot-to-lot buildings and for bypass.
Colder Predicted to Become Warmer
Warming up in Toronto.
Lake-effect winter weather dumps loads of snow on Canada’s largest city yearly. But Toronto is predicted to become hotter and wetter, leading city officials to adapt to the changing weather conditions.
A climate study from 2011 predicted Toronto’s daily maximum temperature from 2000 to 2009 of 37°C (98.6°F) will increase to 44°C (111°F) between 2040 to 2050. The study also forecasted the city’s daily maximum rainfall of 66 mm (2.6 in.) to jump to 166 mm (6.5 in.) during the same period.
The predicted changes increase the city’s risk for flooding events, extreme heat and power outages. So, the city is recommending all new buildings be able to mitigate flood events, improve thermal resilience and improve backup power generation, according to Toronto’s Zero Emissions Buildings Framework.
The framework includes a resilience checklist to guide new building construction. To offset flooding events, the guidelines recommend three methods to reduce overland runoff:
- “Retain storm water on-site to same level of annual volume of overland runoff allowable under pre-development conditions;
- Retain at least the first 5 mm (0.2 in.) from each rainfall through rainwater reuse, on-site infiltration and evapotranspiration; and
- Retain 10 mm (0.4 in.) of each 24 hour rainfall event, or 70% of total average.”
The recommendations reduce the risk of flooding events affecting building systems, which decreases the cost for building repairs, according to the report.
To protect people from extreme heat events, Toronto recommends buildings be designed with thicker building envelopes, lower glazing ratios and lower incidences of thermal bridging, among other tactics.
Well-insulated building envelopes create more stable indoor temperatures during power outages in the summer and winter, said Lisa King, a senior environmental policy planner for the City of Toronto. Well-insulated building envelopes are energy efficient and help keep people comfortable during extreme weather with no power.
The guidelines also recommend buildings have backup power generation for a minimum of 72 hours, allowing people to shelter in place, she said. This helps Toronto run more smoothly during an emergency.
“This allows emergency responders to focus on the larger problems at hand and provides an efficient use of City resources,” King said.
The Cost of Resiliency
No two cities are the same, and the threats facing coastal communities also differ.
While cities have to develop personalized strategies to strengthen their communities, not all resiliency measures are outrageously expensive.
And rebuilding after every extreme natural disaster can also add up.
A total of 212 weather and climate disasters since 1980 have caused more than $1.2 trillion in damages, the National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Environmental Information reported. As of July 7, NOAA reported nine disaster events in America with losses exceeding $1 billion in 2017.
That statistic did not include Hurricane Harvey. In 2016, 15 weather events caused more than $47 billion in damages and killed 138 people, according to NOAA.
Ideally, resiliency measures would strengthen buildings and also save lives. In practice, resiliency measures would have day-to-day benefits, such as elevating buildings to combat storm surges creates more green space for recreational use and adding more insulation to help ride out a power outage creates a more comfortable space, Unger said.
“(Resiliency is) basically an insurance policy,” he said.
That insurance policy is predicted to be used more in the coming years.
NOAA’s July 2017 climate report stated that 2017 could rank in the top three warmest years on record. The same administration said that 2016’s average temperatures were warmer than 2017’s temperatures through July.
No matter the reason, extreme weather disasters will happen, and resilient buildings could help save lives, but being prepared for the unknown is the challenge.
Communities recently affected by these events oftentimes focus on resiliency measures during the recovery phase, according to Rachel Minnery, Fellow AIA, the senior director of sustainable development policy for the American Institute of Architects.
Their rationale might be economic-focused to prevent the loss of so many assets during the next weather event or based on the hope of strengthening the community to save lives.
On the other hand, Lstiburek said some resiliency measures may be propelled by concerns that are mainly political and can sometimes drive up a project’s cost. But other resiliency initiatives are useful in certain areas that are prone to frequent climatic events, or for efforts to fortify the power grid, which he said is unreliable.
The challenges of planning for the unpredictable are vast and sometimes unanswerable. Are people building resilient communities fast enough? Are they building those communities to be strong enough?
But the resiliency efforts will be put to the test; it is just a matter of when.
“The proof is going to be the next big storm,” said Landon Smith, the City of Orange Beach’s chief building official and floodplain administrator. •