Case Study: San Francisco Bay Bridge East Span Design-Construction Interface Failures (2007)

Project Overview
• Name: San Francisco-Oakland Bay Bridge East Span Replacement
• Location: San Francisco, California
• Year: 2007
• Project Size: $6.4 billion
• Scope: Construction of a new self-anchored suspension bridge span
• Lead Agencies/Contractors: California DOT (Caltrans) /

Category of the Issue, Problem, or Challenge
• Design
• Structural & Interface Engineering

Summary of the Issue, Problem, or Challenge
During construction, misalignment between designed bridge components and fabricated steel segments required on-site modifications and partial dismantling. Interface issues arose from discrepancies in tolerances and lack of integrated design-construction workflows.

Root Cause Analysis

• Inadequate tolerance specifications for critical connections.
• Poor integration of design and fabrication teams’ models.
• Insufficient mock-ups or prototype testing before large-scale fabrication.
• Limited use of digital tools for interface management.

Impacts Due to the Issue, Problem, or Challenge
• Construction delays of 10 months due to rework and corrective measures.
• Increased costs by over $30 million.
• Strained relations between contractors and design teams.

Corrective Actions Taken

1. Revised tolerance criteria with tighter control measures.
2. Improved coordination between designers and fabricators using 3D models.
3. Conducted full-scale mock-ups and prototype testing before fabrication.
4. Adopted advanced digital interface management platforms.

Lessons Learned

• Tolerance specifications must be realistic and strictly enforced.
• Early and continuous coordination between design and fabrication is critical.
• Mock-ups reduce risk of large-scale interface issues.
• Digital interface management tools improve accuracy and reduce errors.

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

• Are tolerance limits clearly defined and communicated?
• Is there a collaborative workflow between design and fabrication teams?
• Are physical or virtual mock-ups used to validate designs?
• Are advanced interface management tools implemented?