Case Study: Cost Overrun from Weather-Related Delays on I-35W Mississippi River Bridge Replacement (Minneapolis, MN, 2008)

Project Overview
• Name: I-35W Mississippi River Bridge Replacement
• Location: Minneapolis, Minnesota
• Year: 2008
• Project Size: $234 million
• Scope: Replacement of a collapsed bridge with a new, modern structure
• Lead Agencies/Contractors: Minnesota Department of Transportation (MnDOT) /

Category of the Issue, Problem, or Challenge
• Weather Impact
• Cost Management

Summary of the Issue, Problem, or Challenge
Unexpected severe weather conditions, including heavy rains and early winter storms, caused repeated work stoppages and equipment inefficiencies, leading to increased labor and equipment costs beyond original budget.

Root Cause Analysis

• Severe Weather: Prolonged rainy periods and early freezing hampered concrete curing and steel erection.
• Inadequate Weather Risk Planning: Project schedule did not incorporate sufficient weather contingencies.
• Resource Inefficiency: Idle labor and equipment due to weather delays increased costs.
• Accelerated Schedule Pressure: Attempts to recover lost time led to overtime premium pay and expedited material shipping.

Impacts Due to the Issue, Problem, or Challenge

• Project costs increased by approximately 18% due to weather delays.
• Project completion delayed by several months.
• Increased public and political pressure to manage costs and schedule.

Corrective Actions Taken

1. Revised project scheduling to include seasonal weather buffers.
2. Implemented improved weather monitoring and forecasting integration.
3. Utilized weather-resistant materials and construction techniques where feasible.
4. Developed contingency plans for resource allocation during weather delays.

Lessons Learned

• Weather risks must be carefully analyzed and incorporated into project budgets and schedules.
• Effective contingency planning minimizes cost impacts of unavoidable delays.
• Flexible resource management reduces idle time costs during weather disruptions.

Audit & Prevention: Project Control Questions to Ask on Future Projects to Help Control the Situation

• Has weather risk been quantified and included in cost estimates?
• Are schedules flexible enough to accommodate expected weather delays?
• Are contingency plans in place for labor and equipment utilization during weather interruptions?