Case Study: San Francisco Bay Bridge Retrofit Hampered by High-Strength Bolt Shortages (2021)
Project Overview
• Name: Bay Bridge Eastern Span Seismic Retrofit
• Location: San Francisco, California
• Year: 2021
• Project Size: $550 million
• Scope: Seismic retrofit involving replacement and reinforcement of critical structural connections
• Lead Agencies/Contractors: Caltrans /
Category of the Issue, Problem, or Challenge
• Supply Chain Disruption
• Fasteners and Structural Hardware
Summary of the Issue, Problem, or Challenge
The retrofit project encountered delays when deliveries of high-strength structural bolts were delayed due to a global shortage of alloy steel and manufacturing capacity constraints.
Root Cause Analysis
- Alloy steel shortages driven by increased demand in automotive and aerospace sectors.
- Limited number of manufacturers qualified to produce seismic-grade bolts.
- Insufficient lead time for procurement and qualification of alternate suppliers.
- Lack of inventory buffers for critical fasteners.
Impacts Due to the Issue, Problem, or Challenge
• 3-month delay in bolting and structural assembly phases.
• Increased costs for rush manufacturing and alternate sourcing (~$1.8 million).
• Potential compromise in schedule for seismic safety certification.
Corrective Actions Taken
- Expanded supplier base and qualified alternative bolt manufacturers.
- Instituted early procurement protocols for critical hardware.
- Maintained safety and quality standards despite schedule pressures.
Lessons Learned
- Critical structural hardware supply requires early and diversified sourcing.
- Industry-wide demand fluctuations impact niche construction materials.
- Quality certification processes must be balanced with schedule pressures.
Audit & Prevention: Project Control Questions to Ask on Future Projects to Help Control the Situation
- Are critical hardware suppliers diversified and qualified?
- Are procurement schedules aligned with manufacturing lead times?
- Is quality certification integrated into procurement and scheduling?