An innovative solution powered by precast concrete could make flooding a thing of the past.
By Mark Crawford


SAFE ConnectModules

Though Mother Nature is beautiful, she can pack a powerful punch. Flooding and earthquakes, which can destroy communities with little warning, are a constant threat around the world. Climate change and rising sea levels are making flooding more frequent and severe – in fact, some scientists believe that sea levels could rise by six feet or more by 21001. In the U.S. alone, from 1980 to 2016, 26 flooding events totaled more than $110 billion in damages, or $4.3 billion per event2

So what does society do in response? Create expensive barriers? Move to higher ground and abandon coastlines? Simply accept flooding as an act of nature and rebuild, time after time?

Instead, what if a city could rise and float over incoming floodwaters and return intact to its original level after the water recedes?

That’s exactly what Greg Henderson, founder and CEO of Los Gatos, Calif.-based Arx Pax, proposes with his patented SAFE Foundation System. Using the system, a floating community simply rises when flooding strikes or remains stable in the event of an earthquake. The SAFE System improves the resiliency of structures in coastal areas and flood zones by building them over water.

The SAFE Foundation System depends on precast concrete to create long-term resiliency. Thanks to precast concrete components, Henderson’s solution features a lifespan of approximately 100 years, creating unmatched resiliency in challenging environmental conditions.

3 Part Foundation Community Cross Section V2
These renderings depict how the SAFE Foundation System works. Using the system, floating communities are unaffected by flooding and earthquakes. Photos courtesy: Arx Pax Labs.

An innovative, three-part system

“No matter how green your building is, it’s not sustainable if it cannot withstand an event,” Henderson said. “As an architect and builder, I knew there had to be a way to build more responsibly in areas subject to earthquakes, floods and rising sea levels.”

The SAFE Foundation System isolates destructive forces so they do far less harm. Arx Pax’s patented, three-part foundation system offers a unique combination of architecture and engineering technologies. It is designed to float multistory buildings, roads and utilities in just a few feet of water. Built on precast concrete pontoons, the system is scalable and can support not only homes, but taller commercial buildings covering an area of several city blocks.

During his architectural studies at the University of California, Berkeley, Henderson studied the houseboats in Mission Bay and how they were impervious to earthquakes and floods. This led him to examine Evergreen Point Floating Bridge, which carries Seattle drivers across Lake Washington to the suburbs.

He realized his vision of a floating, self-adjusting environment could draw on the already-proven technologies used to design floating concrete bridges and runways. Evergreen Point Floating Bridge was built on 20 acres of pontoons – 70 of which were recently replaced.

“We are taking everything they have done, all the construction and concrete mix designs, all the same engineering principles, and scaling it down,” Henderson said.

The idea is straightforward:
  1. Dig a shallow, permeable depression (containment vessel) and let it fill with water
  2. Build a floating concrete foundation roughly the size of the containment vessel on top of the water
  3. Construct the community on top of the foundation
If a flood occurs, the community simply rises. If an earthquake strikes, the buildings are unaffected by the violent shaking of the earth below because the community is floating on a shallow pool of water and is uncoupled from the earth.

Evergreen Point Floating Bridge
The Evergreen Point Floating Bridge, which uses a system similar to the Arx Pax solution, is designed to handle a 20-foot drop in water level. Photo courtesy: Arx Pax Labs

The precast concrete components that line the containment vessel and float the foundation are critical to the success of the system.

“Precast is a fantastic product,” Henderson said. “Whenever you can move a construction process from the field to an indoor site, you improve quality, efficiency and reliability, and reduce costs. A controlled environment is essential for delivering consistent, highly reliable products as well as carrying out secondary operations such as applying epoxy coatings.”

Precast pontoons for the Evergreen Point Floating Bridge
Precast pontoons for the Evergreen Point Floating Bridge were produced at one of two dry docks. Photo courtesy: Arx Pax Labs

Precast makes it happen

The first step is excavating a 10-foot-deep depression or pool that connects to a nearby river or bay, or fills with groundwater. In order for the containment vessel to respond to the hydraulic forces in the area, the sides and bottom must be permeable. This is accomplished with U-shaped precast blocks that are crib-locked along the walls and interlocked and embedded across the floor. This creates enough permeability so the pool can fill naturally with groundwater or inflow from the tides.

The second step is constructing the floating base. Large, 8-foot-by-20-foot precast concrete pontoons are assembled into groups and locked together to make a broad, stable platform. When completed, the platform will float in about eight feet of water. Tethered securely to the containment vessel, the platform will not drift away during severe flood events.

“We are using exact drawings from the bridge for the pontoons to explain SAFE to building departments,” Henderson said. “The same size, built the same way, anchored the same way. We know it works.

“Once the building officials understand the basic idea, we then present our construction documents that include our precast ‘kit of parts.’”

Henderson added that the SAFE System currently calls for 7,500-psi portland cement, but Arx Pax is experimenting with different mixes to further enhance the solution.

Once the floating construction surface is ready, contractors build the community on top, complete with roads, landscaping and utilities. For added security, the buildings are attached to anchor points on the pontoons.

resilient precast pontoons
Arx Pax is designing resilient precast pontoons that can be shipped via traditional transportation methods. Photo courtesy: Arx Pax Labs

Moving forward

Henderson’s pilot project – a 1.5-acre mixed-use project – is lined up for a flood plain in San Francisco Bay. He’s hopeful the project will be approved in about one year. Once given the green light, construction will take two years. In the meantime, he is busy dealing with technological, regulatory and financial challenges. As funding comes in, he plans to start building high-quality reusable molds for the precast pontoons.

Henderson will also continue experimenting with concrete mixes.

“We want to show everyone that we are intent on improving the process at every step,” he said. “For example, we will determine the minimum wall thickness required for the pontoons, based on mass and amount of water displaced. We are also looking at the possibility of using UHPC (ultra high performance concrete) for its strength, longevity and resistance to seawater.”

Staying SAFE with Precast
Photo courtesy: Arx Pax Labs
SAFE Foundation System is an eye-opening alternative to the reactive “rebuild and retreat” model. Instead of retreating or rebuilding in the aftermath of a flood, Henderson’s system allows developers and engineers to be proactive in environmentally critical areas. Also, because it is scalable and uses local resources, the system can be set up anywhere flooding occurs.

“We’re helping developers, architects, aid organizations and governments rethink how they can build, rather than just react to disasters,” Henderson said. “We are looking for strategic partners around the world who share this vision. It is important to value-engineer this system and get it out into the world for the people who need it.”

Arx Pax is also considering a pilot project with the Republic of Kiribati – a small, low-lying island nation in the Pacific Ocean that floods every year – to improve the resiliency of its structures. In addition to floating communities, plans could call for floating farms (the country loses considerable farmland due to flooding) that also collect and store rainwater.

The SAFE Foundation System enables more affordable housing and more sustainable construction techniques by separating the buildings, infrastructure and open spaces of communities from destructive natural forces. It is critical to the Arx Pax mission to partner with precast concrete companies that want to be problemsolvers and long-term partners in improving social conditions around the world.

“Every year we see communities, homes and lives destroyed by flooding,” Henderson said. “Instead of spending billions on rebuilding after disasters, we can build responsibly and sustainably so communities will last for generations. High-value projects are now possible in unbuildable areas, creating more opportunities for profitable, resilient communities.

“By working in harmony with natural forces to protect communities, we can provide the next level of sustainability for generations to come.”

Mark Crawford is a Madison, Wis.-based freelance writer who specializes in science, technology and manufacturing.

Acknowledgement: The article has been reproduced from National Precast Concrete Association (http://precast.org/) with its due permission.

  1. https://www.washingtonpost.com/news/energy-environment/wp/2016/03/30/antarctic-loss-could-double-expected-sea-level-rise-by-2100-scientists-say/?utm_term=.38ba
  2. https://www.climate.gov/news-features/blogs/beyond-data/2016-historic-year-billion-dollar-weather-and-climate-disasters-us
Precast & PEB Construction Opportunities for Entrepreneurs
C. A. Prasad, Director, Metey Engineering & Consultancy and President, PSI, Hyderabad, guides entrepreneurs on the various aspects of Precast and PEB construction business. Quality assurance and timely construction using Precast and PEB produced

Read more ...

Autoclaved Aerated Concrete Blocks
A sunrise segment in India’s building materials industry, the AAC block is finding preference over the red brick and emerging as the future of building construction. Mohit Saboo, Director & CFO BigBloc Construction

Read more ...

A Stellar Modernization of Construction With Precast in NCR, India
What influenced the Stellar Group’s decision to build with precast and invest in a precast plant. The well-known Indian ‘Stellar Group’, which has been successfully working in the construction business for over 25 years, is convinced that precast is the future

Read more ...

Sardinian industry leader invests in automated mould from Progress Group to advance production
Recently, a highly automated mould for the production of pillars from Tecnocom, a company of the Progress Group, has been installed to help industry leader Consultecna stay ahead. Francesco Pireddu explains the decision made in favour of automation although

Read more ...

AHCT’s Smart Solutions for Smart Contractors
Technology companies have developed hardware and software solutions to help manage every aspect of a construction project, no matter how complex or massive the project may be. Harsh Pareek, Regional Sales Director, India and SAARC, Trimble Solutions

Read more ...

Echo Precast Engineering Helps Modernize Pruksa’s Precast Plants
Thailand’s real estate developer Pruksa, a leader in the building sector, modernizes its building solutions with automated hollow core production plant equipped with machinery from Echo Precast Engineering, a company of the PROGRESS GROUP. Real estate developer Pruksa

Read more ...

Dongyue Machinery Group gearing up to meet rising demand for AAC Bricks in India
Dongyue Machinery Group is offering Autoclaves Aerated Concrete (AAC) blocks, brick blocks, hollow blocks, curb stones, color blocks etc. AAC Blocks, which are lightweight concrete blocks, use less cement compared to traditional cement bricks, and are therefore eco-friendly

Read more ...

B.E. Billimoria Changing the Face of India
BE Billimoria & Company is one of India’s leading firms of civil engineering construction contractors. Ranging from commercial, residential spaces to some of the most iconic buildings in the country, like the 316-meter Namaste Tower, are among their project list

Read more ...

Advanced Concrete Curing Systems from Kraft Curing Systems GmbH
Kraft Curing Systems GmbH is offering advanced concrete curing systems that optimize the hardening process of concrete. Kraft provide numerous solutions, from vapor-based (steam) systems mainly for the precast industry, to heating/air circulation systems

Read more ...

LARCO partners with ECHO Precast to set up production site for prefab elements
The production site of LARCO PREFAB S.A. in Welkenraedt, Belgium opened in 2018 and has grown consistently over the years. LARCO produces a range of prefabricated concrete elements such as hollow core slabs, columns, wall panels, soccles

Read more ...

Special prefabricated elements specialist Klaus relies on fully individualised automation solutions
Klaus Hoch- und Tiefbau GmbH is upgrading its machines in the precast concrete plant with several automated systems from progress Maschinen & Automation and Tecnocom - companies of the Progress Group. With the individualised reinforcement machines

Read more ...

Prefab Housing
Civil Construction in India has not been as much industrialized as it has been in the West. Presently, it shares barely 1-2% of the real estate market, though as per a recent study, it is expected to grow @8.5% in the decade of 2016-2026

Read more ...

Light House Projects by Skeleton
The increasing demand for residential units in the country with speedier construction, has encouraged use of innovative technologies that are being practiced the world over. Structural steel with its in-built attributes when integrated

Read more ...

Solutions from Mapei for Precast Concrete
Precast concrete is produced by casting concrete in a re-useable mould or form, which is then cured in a controlled environment. To ensure durability, high strength, low water cement ratio, and improved rheology, use of concrete admixtures is compulsory

Read more ...

Aurobindo Realty Teams up with Precast Expert Elematic to Create History
Aurobindo Realty & Infrastructure, one of the frontrunners in the realty sector in South India, is confident that the southern region will see numerous construction projects being launched during the next 10 years and even beyond

Read more ...

Construction Technologies for Speedy Delivery of Projects
C. A. Prasad, President PSI & Director, Metey Engineering & Consultancy, Hyderabad, discusses the various new construction technologies being adopted by developers and builders in India, and their merits and demerits

Read more ...

Prefabricated Volumetric Modular Construction Prospects & Challenges
Ajay Chourasia, Sr. Principal Scientist, CSIR-Central Building Research Institute (CBRI), Roorkee, reviews the general concepts, PVMC connections, and recommendations for technological interventions and alternate connection systems

Read more ...

Joints in Precast Construction
C. B. Kameswara Rao, Professor, National Institute of Technology, Warangal, gives a presentation of different types of joints in precast construction and of the research done at NITW. Connections and joints are responsible for stability as well as strength

Read more ...

Offsite Construction
Srinidhi Anantharaman explores offsite building construction in a holistic manner and provides an overview of the entire design and construction lifecycle of such buildings, along with the compulsions of architectural, structural and services, design decisions

Read more ...

3D Modular Precast & Prefinished Toilet/Kitchen
Saurabh Purandare, Director, & Khaja Rasool, Structural Engineer, Innovela Building Solutions, Pune, discuss an out-of-the-box construction approach for meeting today’s call for shorter timelines and reduced cost in construction, while ensuring the highest

Read more ...

×
Sign-up for Free Subscription
'India Construction Week'
Weekly e-Newsletter on Construction Industry
Get the latest news, product launches, projects announced / awarded, government policies, investments, and expert views.
Click here to subscribe.
×