Corrosion, tides, boat wakes, tropical storms, and hurricanes can all contribute to seawall damage and, ultimately, failure. Additional causes undermine the structure on the landward side. Rainfall creates more hydrostatic pressure than rising and falling tides. Every time it rains or the irrigation system runs (and every time the tide goes out) all of the groundwater above the waterline needs a place to go. Massive pressure can build up if that water is trapped on the landward side, putting immense stress on the structure. (Read more in the article, How Soil Instability Causes Seawall Damage.) That is a recipe for seawall failure that can be avoided if you know the signs.
Soil Depressions Near the Seawall
Soil depressions appear due to the loss of soil near the structure. Water is seeping through or underneath the seawall, weakening the structure and contributing to soil erosion. Strong surrounding soil is critical to a healthy seawall.
Rust Stains on the Surface
Rust stains are a sign of corroded rebar inside the concrete. Corroded rebar expands, cracking and destabilizing the structure.
Movement or Shifting of the Seawall
Hydrostatic pressure and/or lack of supporting soil around the structure can cause sections of the wall to move or shift over time.
Cracks in the Concrete
Cracks in the concrete can be caused by spalling due to rebar corrosion, or movement due to hydrostatic pressure and unstable soil.
Additional Signs of Seawall Failure
- Blocked or clogged weep holes (vents that are used for draining landward side water build-up to relieve hydrostatic pressure).
- Sand or soil deposits at the bottom of the wall panel joints on the water side. This indicates sediment seeping through the joints from the landward side.
- Damage to structures up to 100 feet away. Water infiltration on the landward side can expand a great distance when proper venting/drainage is not occurring. Look for sinkholes, depressions, and/or sunken concrete in the general area surrounding the seawall.
Seawall Repair Network’s Proprietary Repair Process
Let’s review the proprietary repair process used by Seawall Repair Network’s preferred marine contractors. First, crews perform deep injections of SW-RP1 repair material directly behind each panel joint in the seawall. This process fills all the voids while permeating and strengthening the soil. The permeated soil becomes as hard as crystalline bedrock. Next, a new pressure relief system is created by coring through weep hole channels and the layer of resin that has been installed behind them. These new channels extend through the permeated soil and into the soil on the landward side. Proprietary pressure release technology is then installed to regulate the release of hydrostatic pressure from any new water that may form behind the wall in the future. Because pressure release technology also stops landward-side soil from passing through the dewatering channels, it prevents new erosion and void formations. If needed, seawall preservation treatments can also be applied to the concrete. The support of high-strength SW-RP1 repair material, combined with the regulation of hydrostatic pressure and concrete preservation treatment protects the seawall from subsequent movement, damage, or failure.