Case Study: QC Breakdown in Bridge Deck Waterproofing on Portland Bridge Project (Oregon, 2016)

Project Overview
• Name: Portland Bridge Replacement
• Location: Portland, Oregon
• Year: 2016
• Project Size: $620 million
• Scope: Replacement of bridge decks with waterproofing membrane installation
• Lead Agencies/Contractors: Oregon Department of Transportation (ODOT) /

Category of the Issue, Problem, or Challenge
• Quality Control
• Materials
• Structural

Summary of the Issue, Problem, or Challenge
Waterproofing membrane applied with improper surface preparation and inconsistent thickness led to leaks and premature deterioration.

Root Cause Analysis

  • Inadequate inspection of surface cleanliness and moisture levels prior to membrane application.
  • Lack of standardized application thickness monitoring.
  • Insufficient training and supervision of applicators.
  • Poor documentation of QC checks during application phases.

Impacts Due to the Issue, Problem, or Challenge

  • Delay of 4 months due to membrane removal, surface re-preparation, and re-application.
  • Additional costs for materials and labor.
  • Increased risk of corrosion and deck damage if uncorrected.

Corrective Actions Taken

  1. Developed detailed surface preparation and application checklists.
  2. Introduced non-destructive testing to verify membrane thickness and adhesion.
  3. Enhanced applicator training and supervision programs.
  4. Established thorough QC documentation procedures for all membrane work.

Lessons Learned

  • Surface preparation is as important as membrane quality.
  • Monitoring application consistency ensures long-term performance.
  • Training and documentation support better QC outcomes.

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

  • Are surface preparation standards strictly enforced and verified?
  • Is membrane thickness monitored and tested?
  • Are applicators trained and supervised adequately?
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