Case Study: Owner-Mandated Redesign Halts Retaining Wall Construction in Pennsylvania (2021)
Project Overview
• Name: I-76 Slope Stabilization & Retaining Walls
• Location: Pittsburgh, Pennsylvania
• Year: 2021
• Project Size: $145 million
• Scope: Roadside slope stabilization and retaining wall reconstruction
• Lead Agencies/Contractors: Pennsylvania DOT (Owner) /
Category of the Issue, Problem, or Challenge
• Contract Owner
• Mid-Construction Design Changes
Summary of the Issue, Problem, or Challenge
PennDOT issued a mid-construction directive to redesign 2 retaining walls based on new geotechnical studies, pausing fieldwork for 10 weeks while engineering and permits were revised.
Root Cause Analysis
- Owner authorized early construction start before full geotechnical review.
- Site conditions revealed wall foundation risks not accounted for in original design.
- Design changes required revised calculations, drawings, and re-permitting.
Impacts Due to the Issue, Problem, or Challenge
- Construction halted for redesign, delaying adjacent earthworks.
- Cost increase of $7.3 million due to new foundation materials.
- Contractual dispute over cost liability for owner-initiated changes.
Corrective Actions Taken
- PennDOT restructured design review workflows to delay NTP until final investigations.
- Geotechnical peer reviews were added prior to releasing construction packages.
- Contingency fund for owner-driven changes was added to future contracts.
Lessons Learned
- Owners must complete all critical investigations before issuing NTP.
- Midstream design changes impact schedule, cost, and contractor trust.
- Shared risk provisions help mitigate redesign disruption.
Audit & Prevention: Project Control Questions to Ask on Future Projects to Help Control the Situation
- Are site conditions and design packages fully validated pre-construction?
- Does the contract define liability for owner-initiated design revisions?
- Is there a pre-established process for rapid redesign and approval?