Case Study: New York Subway Station Structural Design Errors Delay Completion (2019)

Project Overview
• Name: NYC Second Avenue Subway Phase 2
• Location: New York City, New York
• Year: 2019
• Project Size: $1.8 billion
• Scope: Construction of underground subway station and tunnel segments
• Lead Agencies/Contractors: MTA /

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

Summary of the Issue, Problem, or Challenge
Structural design errors involving load calculations and waterproofing detailing led to re-engineering of key station components after construction had begun, causing delays and additional costs.

Root Cause Analysis

• Incorrect load assumptions for temporary construction supports.
• Overlooked waterproofing details causing potential leakage risks.
• Insufficient peer review of critical design elements.
• Delayed incorporation of updated code requirements.

Impacts Due to the Issue, Problem, or Challenge
• 8-month delay to correct and rebuild affected components.
• Cost increases of approximately $12 million.
• Heightened regulatory oversight on future subway projects.

Corrective Actions Taken

1. Comprehensive peer review process added for critical design areas.
2. Design updates incorporated advanced waterproofing solutions.
3. Enhanced training on current code requirements for design teams.
4. Improved coordination between designers, contractors, and regulators.

Lessons Learned

• Critical design elements must undergo multiple levels of review.
• Temporary construction load designs are as important as final structure designs.
• Waterproofing in underground projects is crucial and must be detailed carefully.
• Keeping design teams updated with latest codes avoids costly changes.

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

• Are temporary construction load requirements properly analyzed?
• Is waterproofing design rigorously detailed and reviewed?
• Are peer reviews mandated for high-risk design elements?
• Is the design team current with all relevant code changes?