Case Study: Crane Boom Collapse at Tappan Zee Bridge Construction (New York, 2010)

Project Overview
• Name: New NY Bridge at Tappan Zee
• Location: Hudson River, New York
• Year: 2010
• Project Size: $3.9 billion total project
• Scope: Heavy lift operations involving crane assembly and lifting of bridge components
• Lead Agencies/Contractors: NY State Thruway Authority /

Category of the Issue, Problem, or Challenge
• Equipment Failure
• Lifting Operations

Summary of the Issue, Problem, or Challenge
During heavy lift operations, the boom of a large crawler crane unexpectedly collapsed due to overstressing of a boom section, causing the load to drop partially and damaging components. No injuries were reported, but the incident caused significant project delays.

Root Cause Analysis

• Overloading: The crane was operated near the upper limits of its capacity for the boom length and load radius.
• Fatigue and Structural Defects: Undetected metal fatigue and a crack in the boom contributed to failure.
• Inspection Gaps: Regular non-destructive testing of critical boom sections was insufficient.
• Operator Error: Possible miscalculation of load radius and boom angle under dynamic conditions.

Impacts Due to the Issue, Problem, or Challenge

• Damage to bridge components and crane equipment.
• Project delays and increased costs for repairs and inspections.
• Revised crane operation procedures and safety reviews.

Corrective Actions Taken

1. Enhanced inspection protocols for crane booms, including ultrasonic and magnetic particle testing.
2. Review and enforcement of load charts and operating limits.
3. Additional operator training focused on load dynamics and boom stress awareness.
4. Installation of load monitoring and boom stress sensors on cranes.

Lessons Learned

• Crane components are vulnerable to fatigue and require rigorous inspection.
• Adherence to load charts and operational parameters is critical for safety.
• Dynamic loading effects must be considered in lifting operations.

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

• Are crane boom components regularly inspected using advanced NDT methods?
• Are crane operators fully trained and certified on load charts and operational limits?
• Are real-time load and stress monitoring devices installed and monitored during lifts?