Case Study: Subcontractor Poor Welding Quality Causes Structural Rework on Texas Highway Overpass (2017)

Project Overview
• Name: Houston Highway Overpass Expansion
• Location: Houston, Texas
• Year: 2017
• Project Size: $350 million
• Scope: Overpass structural steel installation and welding
• Lead Agencies/Contractors: Texas DOT /

Category of the Issue, Problem, or Challenge
• Subcontractor Management
• Quality Control & Structural Integrity

Summary of the Issue, Problem, or Challenge
Welding subcontractor’s inconsistent welding practices led to cracks and defects in critical steel joints, necessitating costly repairs and delays.

Root Cause Analysis

• Lack of adherence to welding procedure specifications.
• Inadequate welder qualification and certification oversight.
• Insufficient inspection and non-destructive testing during welding.
• Poor communication between subcontractor QC and prime contractor QA teams.

Impacts Due to the Issue, Problem, or Challenge

• Structural steel rework causing a 4-week delay.
• Additional costs for repair labor and materials.
• Heightened safety concerns during construction and operation.

Corrective Actions Taken

1. Re-certified welders and tightened welding procedure controls.
2. Increased frequency and rigor of NDT inspections.
3. Improved coordination between subcontractor QC and prime contractor QA.
4. Conducted training workshops on welding quality standards.

Lessons Learned

• Welding quality is critical to structural safety and schedule adherence.
• Proper certification and inspections prevent costly defects.
• Collaboration between QC/QA teams enhances defect detection.

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

• Are welders certified and following approved procedures?
• Are NDT inspections performed at key stages?
• Is there effective communication between subcontractor and prime contractor QA/QC?