Storm Intake Stabilization and Waterproofing in Solon, Iowa

Project Background

In the fall of 2023, the City of Solon identified multiple storm intakes with concrete sinking and erosion issues under the intake aprons. These issues posed significant risks to road integrity and public safety. Previous repair methods had proven ineffective, prompting city officials to seek a long-term stabilization solution. Concrete PolyFix was consulted to assess the feasibility of raising the aprons and void filling to stabilize the backfill beneath the street and in front of the storm intake boxes.

Scope of Work

The primary objectives of the project included:

• Storm Intake Apron Raising and Void Filling
  • Lift and stabilize sinking aprons and adjacent street slabs.
  • Prevent further erosion and enhance soil stability.
• Backfill Stabilization
  • Ensure long-term soil integrity around storm intake boxes to prevent future erosion.
  • Improve the structural stability of the storm intake system.

Challenges

Key challenges encountered during the project included:

• Addressing significant soil erosion and void formation under storm intake aprons.
• Stabilizing intake boxes that had developed structural cracks and water infiltration.
• Implementing a solution that minimized disruption to roadways and traffic flow.

Solutions

Concrete PolyFix implemented a comprehensive approach using advanced polyurethane technology:

Storm Intake Apron Raising:

• Technology Used: Dual-Component Expanding Polyurethane Foam
• Method:
  • Polyurethane foam was injected beneath sinking aprons and adjacent street slabs.
  • The foam expanded to fill voids, lifting the concrete surfaces back to their original levels.
  • This approach ensured that the street remained level, eliminating potential hazards and preventing further soil displacement.

Backfill Stabilization and Storm Intake Box Waterproofing:

• Technology Used: Single-Component Non-Expanding Polyurethane Foam & Dual-Component Expanding Polyurethane Foam
• Method:
  • In the spring of 2024, the City of Solon identified 28 storm intakes with significant erosion and/or cracked underground intake boxes.
  • During the summer of 2024, Concrete PolyFix applied:
    • Structural stabilization for cracked intake boxes: A single-component polyurethane was injected under and around the intake boxes to create an 8-inch polyurethane barrier for waterproofing and structural reinforcement.
    • Erosion control for intact intake boxes: A less expensive expanding foam was injected under and around the intake boxes to mitigate erosion and enhance waterproofing.

Results

Long-Term Value:

• Durability: The polyurethane solutions provided by Concrete PolyFix offer long-lasting stabilization, reducing the likelihood of future erosion or leakage issues.
• Minimal Disruption: The injection process allowed for quick and minimally invasive repairs, completing 7-8 intake boxes per day.

Cost Savings:

• Avoided Full Replacement Costs: The cost of fully tearing out and replacing storm intake boxes can reach up to $11,500 per intake. In contrast, Concrete PolyFix’s approach offered a cost-effective alternative:
  • Structural stabilization and waterproofing: $2,500 – $2,800 per 5x5x5 intake box.
  • Soil stabilization and waterproofing: $1,400 – $1,600 per intake box.

Conclusion

Concrete PolyFix successfully provided the City of Solon with a durable, cost-effective solution for stabilizing storm intake structures. By leveraging advanced polyurethane technology, the project mitigated further erosion, improved infrastructure longevity, and delivered significant cost savings. This case study highlights Concrete PolyFix’s expertise in delivering innovative and efficient municipal repair solutions.