Causes and Signs of Seawall Failure
Seawalls play a critical role in protecting coastal properties from erosion, storm surges, and other natural forces. However, over time, these structures can face various challenges that may compromise their effectiveness. Seawalls can fail due to a variety of factors, including natural forces, structural degradation, and poor construction. Here are potential ways a seawall can fail and how you can identify the signs and symptoms that might indicate the need for repair or replacement…
Erosion and Undermining
- Failure: Gradual erosion of the soil behind the seawall can weaken its foundation, causing it to sink or collapse.
- Signs and Symptoms: Visible subsidence of the seawall, soil erosion around the base, cracking or tilting of the seawall, or water seeping through gaps.
- Failure: Waves exceeding the height of the seawall can wash over it, eroding the soil behind it and compromising its effectiveness.
- Signs and Symptoms: Frequent wave overtopping during storms, water damage to structures behind the seawall, or weakened soil along the wall’s backside.
Corrosion and Deterioration
- Failure: Exposure to salt water and environmental conditions can lead to corrosion and deterioration of the materials, weakening the seawall’s structural integrity.
- Signs and Symptoms: Rust or corrosion on metal components, visible deterioration of concrete or masonry, cracks, chips, or spalling.
- Failure: Uneven settling of the seawall’s foundation can result in structural instability and cracking.
- Signs and Symptoms: Visible cracks in the seawall, differential settlement causing tilting or sinking, or gaps forming between the wall and the ground.
Seepage and Water Infiltration
- Failure: Water seeping through cracks or gaps in the seawall can erode the soil behind it and compromise its stability.
- Signs and Symptoms: Ongoing water seepage through the seawall, soil erosion behind the wall, or signs of water damage on the landward side.
Aging and Wear
- Failure: Over time, the materials of the seawall may degrade naturally, reducing its strength and stability.
- Signs and Symptoms: Visible signs of wear, weathering, or aging such as fading, cracking, or crumbling.
- Failure: Lack of regular maintenance can allow minor issues to escalate into major problems.
- Signs and Symptoms: Accumulation of debris, vegetation growth, or the presence of visible damage that has gone unaddressed.
- Failure: Changes in water levels, storm frequency, or coastal processes can lead to unexpected stress on the seawall.
- Signs and Symptoms: Frequent storm damage, shoreline retreat, or increased susceptibility to erosion.
Regular inspections and prompt action in response to any of these signs are crucial to preventing seawall failures and ensuring the safety of coastal properties. We recommend at least an inspection by either yourself or a qualified professional from our network on a yearly basis.
Repair or Replacement?
Repairing a seawall using polyurethane grouting and soil stabilization is often considered when the damage is not extensive, and the structural integrity of the seawall can be effectively restored. However, the decision to repair versus replace a seawall depends on several factors. When trying to determine whether to repair or replace, consider these factors…
- Cracks and Gaps: If the seawall has visible cracks, gaps, or voids, Seawall Repair Network®’s SW-RP1 can be effective in filling these voids and stabilizing the soil behind the seawall.
- Erosion: When erosion is apparent in specific areas and the majority of the seawall structure is intact, the repair process can stabilize the soil and prevent further erosion.
- Structural Stability: If the seawall’s structural integrity is still intact and it’s not at risk of imminent collapse, repair material can be used to reinforce and strengthen the existing structure.
- Cost-Effectiveness: Repairing with the seawall stabilization process is more cost-effective (typically 90% less than the cost of replacement).
Seawall Replacement (Too Damaged for Repair)
- Extensive Structural Damage: If the seawall has extensive structural damage such as widespread cracking, severe tilting, or signs of imminent collapse, it might be beyond the point of effective repair.
- Foundation Instability: If the foundation of the seawall has suffered significant settlement or shifting, it could compromise the structural stability even after repair attempts.
- Corrosion and Deterioration: If the seawall’s materials are severely corroded, deteriorated, or weakened, repair efforts might not provide a long-lasting solution.
- Changes in Environmental Conditions: If the coastal environment has changed significantly, such as increased storm frequency or rising sea levels, the seawall might need to be replaced to better withstand these new conditions.
Ultimately, the decision to repair or replace a seawall should be made after a thorough assessment by a Seawall Repair Network® preferred marine contractor. Each network member has been trained to evaluate the extent of the damage, and the potential effectiveness of repair methods, and to offer a long-term sustainable solution. In some cases, a hybrid approach might be taken, where damaged sections are repaired while severely compromised sections are replaced.