MIAMI Seawalls are going nowhere in Florida, despite other natural innovations such as living shorelines.
There are thousands of miles of coastline that will be affected by sea level rise. Some cities and counties, such as Miami-Dade have already called for seawall heights to be raised. Many of the seawalls that will be built in the future are expected to be stronger and more durable than the ones currently in place. They will also be better designed to absorb waves and reduce damage to nearby bay bottoms.
A new development strategy by the University of Miami was created specifically to provide habitat for mangroves, corals and other marine life.
We have to stop doing things in the same way that we have for the past few decades,” Esber Andiroglu, an assistant professor at the University of Miami, stated. She is a focus on building the seawalls of tomorrow. This is a time of innovation.
He is among the private companies and university scientists who are developing new technology for seawall construction. This will be a growing business in the coming decades. According to one estimate, it would cost $75 billion to repair and raise every wall in Florida by 2040.
Harder, better, faster, stronger
The new seawall, which is located next to North Bay Villages Treasures and the Bay Condominium, is noticeably higher than before. Because it is concrete-encased, the second major change is difficult to see.
The seawall cap covers approximately 50 feet and isn’t interlaced using the steel rods (rebar) that are used to reinforce most buildings. Instead, it uses reinforced glass fiber polymer bars. It is twice as strong as steel, weighs 75% less, and doesn’t corrode.
This is a common defect in rebar used for projects that are exposed to salty air or water. This is why older coastal buildings develop menacing cracks if they are not taken care of.
Andiroglu who designed the seawall said that reinforcement with fiber-polymers would completely eliminate this problem. He said that the polymer rebar has been well-tested and is being used more often by the Florida Department of Transportation for projects that are susceptible to salt air.
He said that although the upfront cost of steel is 10% to 15% more than steel, it will be much cheaper over the long-term because it has a much longer life span (100 years or more), as some studies suggest. As it becomes more popular, the price will likely drop.
Seawalls that look like LEGO bricks could also help to reduce the cost of raising them in future. Andiroglus laboratory is testing modular pieces that can easily be added to. This could prove useful as coastal building codes are becoming more strict due to rising sea levels.
People often say, “If I build it too high, then I’m wasting my view, and it won’t happen during my lifetime,” he stated. Modular functions allow seawalls to be increased as it happens. It will also help to spread the financial burden over decades.
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Concrete for Coral Friendly
Concrete, the main ingredient of seawalls, is also ripe to change. It is a major contributor to carbon dioxide emissions that can worsen climate change. Additionally, it can be damaged in humid, salty areas like South Florida.
Concrete is the most widely used material in the world, according to Prannoy Suraneni (an assistant professor at UM) who is dedicated to improving concrete for engineering and the environment.
Suraneni stated that it is easy to change concrete ingredients to make it more durable. There is already an option called ultra-high-performance concrete, and builders across the country are starting to use it more but it doesnt solve every problem, especially on the environmental side.
He stated that it is more difficult to make concrete coral-friendly or resilient.
Research has shown that seawalls with different textures attract different types of marine life better to a smooth wall. His team is currently studying how different concrete mixes, alkalinity and other additives promote healthier growth of marine life. This question is still unanswered.
Perhaps the most important change would be to use saltwater instead of fresh water in concrete seawalls. This would reduce costs and be especially beneficial in countries with depleted drinking water.
Suraneni, after many years of research, has confirmed that seawater can work in concrete. As long as the steel reinforcement is removed, Suraneni believes it can. Steel and salt do not mix.
Seawater can be used in concrete. He said that concrete made from steel is susceptible to corroding. Don’t use steel in such situations. Use glass fiber reinforced plasticmer.
SEAHIVE – Introducing
While seawalls can protect land, they are not good for marine life. If a wave crashes into a mangrove tree or a pile o rocks, it disintegrates the force. If a wave crashes against a straight seawall, however, all that energy is funnelled straight down, scouring nearby sea bottoms and sea life.
Miami-Dade requires that new seawalls have riprap (a pile of rocks) at their base. Mangroves and other coastal plants will grow there if the rocks are high enough that they can be seen from the water.
This is what inspired a group UM scientists to create a riprap substitute, designed with mangroves in mind. They call it SEAHIVE, after the six-sided tubes that stack up to resemble a honeycomb beehive.
It is like an airbag. It dissipates energy by allowing water inside, according to Landolf Rhode Barbarigos (assistant professor at the University of Miami’s college of engineering, and head of the SEAHIVE research team).
After three years of testing the structures inside water tanks, the team has decided to move on to pilot projects in real life. One will be located near North Bay Village’s seawall, while another will be off the coast of Miami Beach as an artificial reef. The third will be debut in Pompano Beach this summer for a snorkeling park called Wahoo Bay.
The plan is to plant coral and mangroves on the SEAHIVE structures of the sunken park, so that residents, especially children, can swim up and enjoy nature firsthand.
Rob Wyre (chairman of Shipwreck Park), creator of another snorkel park for Broward County, said that we expect school groups to be the main attraction. It’s a blank canvas as far as the education side.
Rhode-Barbarigos explained that his team will monitor everything once the structures are in place. They will be able to measure everything, from how fish and plants respond to the structure’s ability to break up waves to how efficient it is at doing so. They will be constructed with the same plastic polymers that were used to build the North Bay Village condo seawall. He said that if all goes well, this technology could be an easy-to deploy solution for waterfront South Florida communities.
We wanted something that was robust, easy-to-implement, easy to produce, and approachable. You can always push the boundaries to be really high-tech later. To have sustainable, equitable and sustainable development, we need low-tech solutions.