AEG, a SOCOTEC Company provided preliminary and final design engineering, geotechnical investigation, testing, and foundation recommendations for the reconstruction of the 41st Street Bridge in Philadelphia, Pennsylvania.

Key Information 

Project Name: 41st Street Bridge

Client: Philadelphia Department of Streets

Location: Philadelphia County, PA

Services Provided: Geotechnical and Advanced Engineering

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Vijay GUPTA

President

Largo, MD|Phoenixville, PA

President

vijay.gupta@socotec.us +1 (484) 920-8010

The Challenge 

Reconnecting Mantua After 22 Years

The original 41st Street Bridge, connecting Mantua Avenue and Poplar Street, had been closed to vehicular traffic for 22 years due to deteriorating structural conditions.

Replacing the aging structure required a bridge capable of crossing both active and former rail infrastructure. The new two-span continuous composite steel plate girder bridge features a 120-foot southern span over active Amtrak tracks and a 112-foot northern span over abandoned Norfolk Southern tracks, supported by concrete abutments and a central pier.

Subsurface conditions added complexity to the project. During drilling, hazardous materials were encountered, requiring specialized handling procedures during the investigation and construction phases.

The Solution

Engineering a Foundation Strategy for Complex Site Condition

PA P3 Major Bridges- Lehigh

AEG developed its engineering approach in accordance with PennDOT’s Design Manual, Part 1, Design Manual 4, and Publications 222 and 293, working in coordination with City and PennDOT personnel.

Services provided included:

  • Preliminary Design Engineering
  • Final Design Engineering
  • Soil Reconnaissance
  • Geological Investigations
  • Review of Published and Unpublished Data
  • Coordination with City and PennDOT Personnel
  • Visual Site Inspections
  • Development of a Subsurface Exploration Program
  • Subsurface Investigation and Testing
  • Geotechnical Analysis
  • Structure Foundation Geotechnical Report (SFGR)
  • Foundation Recommendations
  • Specifications and Contract Details Support

The findings informed the foundation strategy for the replacement bridge, with drilled shafts, also known as caissons, recommended for all substructures.

AEG developed its engineering approach in accordance with PennDOT’s Design Manual, Part 1, Design Manual 4, and Publications 222 and 293, working in coordination with City and PennDOT personnel.

Services provided included:

  • Preliminary Design Engineering
  • Final Design Engineering
  • Soil Reconnaissance
  • Geological Investigations
  • Review of Published and Unpublished Data
  • Coordination with City and PennDOT Personnel
  • Visual Site Inspections
  • Development of a Subsurface Exploration Program
  • Subsurface Investigation and Testing
  • Geotechnical Analysis
  • Structure Foundation Geotechnical Report (SFGR)
  • Foundation Recommendations
  • Specifications and Contract Details Support

The findings informed the foundation strategy for the replacement bridge, with drilled shafts, also known as caissons, recommended for all substructures.

The Results 

Restoring a Critical West Philadelphia Connection

The new 41st Street Bridge was completed ahead of schedule, restoring vehicular connectivity between Mantua Avenue and Poplar Street.

The completed project includes new adjacent retaining walls and catenary structures, along with architectural concrete parapets and fencing addressing safety and aesthetic considerations.

The modernized structure provides a renewed connection for West Philadelphia while supporting the City’s goal of reconnecting neighborhoods through resilient infrastructure.

Planning a Bridge or Infrastructure Project?