Case Study: Inadequate QC in Precast Concrete Segment Installation on Houston Tunnel Project (Texas, 2017)

Project Overview
• Name: Houston Ship Channel Tunnel
• Location: Houston, Texas
• Year: 2017
• Project Size: $1 billion
• Scope: Tunnel boring and precast segment lining installation
• Lead Agencies/Contractors: Harris County /

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

Summary of the Issue, Problem, or Challenge
Misalignment and poor sealing of precast concrete tunnel segments caused water infiltration and required reinstallation during construction.

Root Cause Analysis

• Lack of strict QC during segment manufacture and storage.
• Inadequate alignment verification procedures during installation.
• Poor quality of gasket materials and improper sealing methods.
• Insufficient coordination between fabrication and installation teams.

Impacts Due to the Issue, Problem, or Challenge

• Delay of 3 months to remove and reinstall affected segments.
• Increased costs for repair materials and labor.
• Risk of water damage and operational issues if left unresolved.

Corrective Actions Taken

1. Improved manufacturing QC with tighter tolerances and inspection.
2. Instituted detailed alignment checks and documentation during installation.
3. Upgraded sealing materials and installation protocols.
4. Enhanced collaboration and communication between fabrication and field teams.

Lessons Learned

• QC must cover both manufacturing and field installation phases.
• Detailed verification reduces risk of water infiltration.
• Cross-team communication is key to seamless installation.

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

• Are precast segments inspected rigorously before shipment?
• Are installation tolerances verified and documented?
• Is there strong coordination between fabricators and installers?