Case Study: Cost Overrun from Design Errors on I-70 Mountain Corridor Reconstruction (Colorado, 2010)
Project Overview
• Name: I-70 Mountain Corridor Reconstruction
• Location: Colorado
• Year: 2010
• Project Size: $1.2 billion
• Scope: Reconstruction of mountainous highway section with tunnels, bridges, and retaining walls
• Lead Agencies/Contractors: Colorado Department of Transportation (CDOT) /
Category of the Issue, Problem, or Challenge
• Design Errors
• Cost Management
Summary of the Issue, Problem, or Challenge
Design errors in retaining wall specifications led to structural modifications and costly rework during construction.
Root Cause Analysis
- Insufficient Geotechnical Data: Underestimation of rock and soil pressures on retaining walls.
- Design Miscalculations: Structural designs did not meet required load factors.
- Lack of Peer Review: Designs were not subjected to rigorous third-party reviews.
- Change Management: Slow response to identified errors delayed corrective actions.
Impacts Due to the Issue, Problem, or Challenge
- Cost overruns of approximately 17% due to rework and additional materials.
- Construction delays of nearly five months.
- Increased risk and liability concerns.
Corrective Actions Taken
- Conducted thorough peer reviews of all structural designs.
- Enhanced geotechnical investigation protocols.
- Implemented rapid response teams for design error detection and correction.
- Instituted stronger quality control and design verification processes.
Lessons Learned
- Comprehensive design verification reduces costly construction-phase corrections.
- Accurate geotechnical data is crucial for mountain infrastructure projects.
- Early peer reviews help catch errors before construction starts.
Audit & Prevention: Project Control Questions to Ask on Future Projects to Help Control the Situation
- Are designs peer-reviewed and quality-checked before construction?
- Is geotechnical data comprehensive and recent?
- Are processes in place for swift response to design errors?