Case Study: Central Subway Tunnel – MEP Change Orders from Incomplete Coordination (2018)
Project Overview
• Name: Central Subway Project
• Location: San Francisco, California
• Year: 2018
• Project Size: $1.6 billion
• Scope: 1.7-mile light rail tunnel with underground stations
• Lead Agencies/Contractors: San Francisco Municipal Transportation Agency (SFMTA) /
Category of the Issue, Problem, or Challenge
• Contract Change Order
• MEP Coordination
Summary of the Issue, Problem, or Challenge
Mechanical, electrical, and plumbing (MEP) systems required extensive rework after field crews identified major spatial conflicts with structural and architectural components. These coordination issues resulted in substantial change orders, primarily due to insufficient integration of MEP during design and lack of clash detection before fabrication.
Root Cause Analysis
- Incomplete design at bid stage
- Inadequate use of BIM for coordination
- Accelerated procurement of materials before design finalization
- Field conditions differed from as-built assumptions in drawings
Impacts Due to the Issue, Problem, or Challenge
• Over $90 million in change orders
• Delays to station fit-out and systems integration
• Increased tension between contractor and agency leadership
Corrective Actions Taken
- Required use of federated BIM models for all underground station work
- Instituted “no fabrication without coordination” policy
- Added constructability reviews by third-party MEP consultants
- Contract modifications to share risk of design-driven rework
Lessons Learned
- Full MEP coordination must precede procurement and field work
- BIM is only effective if all trades and disciplines are fully engaged
- Change orders from uncoordinated systems create long-term cost and time impacts
- Schedule compression cannot justify skipping coordination milestones
Audit & Prevention: Project Control Questions to Ask on Future Projects to Help Control the Situation
- Has full MEP coordination been completed before issuing for construction?
- Are BIM clash reports reviewed and resolved prior to fabrication?
- Is there a dedicated MEP lead managing cross-discipline integration?
- Are contract terms clear about responsibility for uncoordinated designs?