Case Study: Labor Strike Halts Seattle Tunnel Approach Construction (2016)
Project Overview
• Name: SR 99 Tunnel North Portal Approach Structures
• Location: Seattle, Washington
• Year: 2016
• Project Size: $85 million (portion of $3.3B Alaskan Way Viaduct Replacement)
• Scope: Approach structures, retaining walls, and ramp construction for tunnel access
• Lead Agencies/Contractors: WSDOT /
Category of the Issue, Problem, or Challenge
• Labor Dispute
• Industrial Relations
Summary of the Issue, Problem, or Challenge
Ironworkers and pile drivers initiated a strike over local union jurisdictional disputes, halting steel erection and piling activities for nearly a month. Mediation was delayed due to overlapping negotiations with a separate tunneling workforce.
Root Cause Analysis
| Factor | Details |
| Jurisdictional Conflict | Dispute over whether steel assembly tasks fell under ironworker or laborer scope |
| Owner’s Role | WSDOT remained neutral, delaying dispute resolution |
| Contract Language | Vague scope definition allowed overlapping claims |
| Delayed Mediation | No pre-arranged labor dispute protocol in place |
Impacts Due to the Issue, Problem, or Challenge
• 28-day work stoppage on critical path structures
• Idle equipment and standby labor costs exceeded $1.1 million
• Construction resequencing led to cost and coordination impacts in adjacent work zones
Corrective Actions Taken
- Union jurisdiction clarified for future scopes via pre-job conferences
- Labor dispute escalation procedure added to future contract boilerplate
- WSDOT created a labor liaison officer position for major urban projects
Lessons Learned
• Jurisdictional clarity must be established early with unions on multi-trade scopes
• Public owners should prepare for active facilitation of labor disputes
• Schedule buffers are needed when multiple high-stakes trades overlap
Audit & Prevention: Project Control Questions to Ask on Future Projects to Help Control the Situation
- Have pre-job union jurisdictional agreements been documented?
- Is there a labor dispute resolution pathway embedded in the contract?
- Are labor disruptions modeled into the project risk register?