Case Study: Partial Deck Collapse During I-95 Overpass Construction (Philadelphia, PA, 2014)

Project Overview
• Name: I-95 Overpass Rehabilitation
• Location: Philadelphia, Pennsylvania
• Year: 2014
• Project Size: $85 million
• Scope: Replacement and rehabilitation of aging overpass decks on I-95
• Lead Agencies/Contractors: Pennsylvania Department of Transportation (PennDOT) /

Category of the Issue, Problem, or Challenge
• Structural Failure
• Construction Safety

Summary of the Issue, Problem, or Challenge
During concrete deck placement on an overpass, a section of formwork failed, causing a partial deck collapse. The incident occurred during wet concrete pouring, putting workers at risk and requiring emergency response and cleanup.

Root Cause Analysis

• Formwork Design Deficiency: Formwork was not adequately designed to support wet concrete weight.
• Inadequate Bracing and Supports: Temporary shoring was insufficient and improperly installed.
• Inspection Lapses: Pre-pour inspections did not identify weaknesses in formwork assembly.
• Poor Communication: Safety warnings from workers were not acted upon in time.

Impacts Due to the Issue, Problem, or Challenge

• Injuries to two workers, though no fatalities.
• Project delay due to cleanup and reconstruction.
• Regulatory investigations and increased scrutiny on formwork safety.

Corrective Actions Taken

1. Revised formwork design standards with higher safety factors and redundancy.
2. Mandatory third-party inspection of formwork before concrete placement.
3. Enhanced worker safety training and incident reporting protocols.
4. Implementation of real-time monitoring during concrete pours.

Lessons Learned

• Formwork systems must be designed and inspected to withstand all expected loads.
• Worker safety concerns should be prioritized with clear communication channels.
• Real-time monitoring can detect formwork distress before collapse.

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

• Has formwork design been independently reviewed for load capacity?
• Are inspections conducted before each concrete placement?
• Is there an effective communication protocol for safety warnings from site workers?