Case Study: Subcontractor Inadequate Soil Testing Leads to Foundation Redesign in Michigan (2020)

Project Overview
• Name: Detroit Riverfront Infrastructure Project
• Location: Detroit, Michigan
• Year: 2020
• Project Size: $320 million
• Scope: Infrastructure improvements including deep foundation work
• Lead Agencies/Contractors: Michigan DOT /

Category of the Issue, Problem, or Challenge
• Subcontractor Management
• Geotechnical & Soil Testing

Summary of the Issue, Problem, or Challenge
Subcontractor’s incomplete soil sampling and testing missed critical weak layers, resulting in foundation design revisions mid-construction with costly delays.

Root Cause Analysis

• Limited borehole coverage and sample collection.
• Inadequate laboratory testing protocols.
• Lack of coordination between geotechnical and structural engineering teams.
• Insufficient oversight and verification by prime contractor.

Impacts Due to the Issue, Problem, or Challenge

• Two-month delay for foundation redesign and rework.
• Additional costs for remediation and redesign.
• Increased risk of long-term foundation performance issues.

Corrective Actions Taken

1. Expanded soil investigation program with additional borings.
2. Adopted comprehensive laboratory testing standards.
3. Improved coordination between geotechnical and design teams.
4. Prime contractor strengthened subcontractor QA oversight.

Lessons Learned

• Thorough geotechnical investigations are essential before construction.
• Coordination between testing and design reduces risk of rework.
• Prime contractor oversight ensures subcontractor compliance.

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

• Are soil investigations comprehensive and verified?
• Is there effective communication between geotechnical and design teams?
• Are subcontractor testing procedures audited regularly?