Case Study: Minneapolis Light Rail Transit Tunnel Design Clash Causes Rework (2017)

Project Overview
• Name: Minneapolis Southwest Light Rail Transit (LRT) Tunnel
• Location: Minneapolis, Minnesota
• Year: 2017
• Project Size: $2 billion
• Scope: Construction of underground light rail tunnels and stations
• Lead Agencies/Contractors: Metropolitan Council /

Category of the Issue, Problem, or Challenge
• Design
• Structural Coordination

Summary of the Issue, Problem, or Challenge
During excavation and tunnel lining installation, design clashes between tunnel structural elements and utility conduits were discovered. The lack of integrated design coordination resulted in costly rework and schedule disruptions.

Root Cause Analysis

• Fragmented design workflows for tunnel structure and utilities.
• Absence of integrated 3D BIM modeling to detect clashes pre-construction.
• Poor interdisciplinary communication and coordination during design.
• Inadequate design review processes focusing on constructability.

Impacts Due to the Issue, Problem, or Challenge
• 6-month project delay due to design modifications and utility relocations.
• Increased project costs by approximately $9 million.
• Greater risk to worker safety due to unplanned adjustments.

Corrective Actions Taken

1. Adoption of integrated 3D BIM models for all underground utilities and structures.
2. Establishment of interdisciplinary coordination teams and regular clash detection meetings.
3. Improved design review procedures with focus on constructability and field input.
4. Enhanced communication protocols among designers, contractors, and utilities.

Lessons Learned

• Integrated design modeling is essential for complex underground projects.
• Regular interdisciplinary coordination prevents costly field conflicts.
• Constructability reviews must include all design disciplines and stakeholders.
• Clear communication protocols are critical to timely issue resolution.

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

• Are all underground utilities and structures modeled in a shared 3D environment?
• Are interdisciplinary coordination meetings held regularly during design?
• Does the design review process include constructability and clash detection?
• Are communication channels open and effective among all parties?