Develop Guidance on Drilled Shaft Response to Collision Force

The 2024 AASHTO LRFD Bridge Design Specifications, 10th Edition, specify a 600-kip equivalent static force (ESF) for vehicle collisions with unprotected bridge columns. Current provisions assume this force transfers directly from the column to the foundation, often a drilled shaft, leading to potentially inadequately sized foundations. Field investigations show that drilled shafts rarely sustain impact damage; instead, failures typically occur at the column-to-drilled-shaft connections or the column. Additionally, the response of soil, concrete, and steel under high strain rates differs from static conditions, increasing material strength and stiffness. Nevertheless, current design provisions provide limited guidance on these dynamic effects, leading to uncertainty in impact load distribution and resistance. This study aims to enhance collision load modeling accuracy, ensuring that drilled shaft-supported bridge substructures are designed more efficiently while maintaining structural resilience. The outcomes will support Texas Department of Transportation (TxDOT) and American Association of State Highway and Transportation Officials (AASHTO) specification updates, optimizing foundation design and mitigating the risk of premature failures at critical connections.

• Record URL:
  • https://library.ctr.utexas.edu/Presto/project=0-7268

Language

• English

Project

• Status: Active
• Funding: $499,960.00
• Contract Numbers:

  0-7268

• Sponsor Organizations:

  Texas Department of Transportation

  125 E. 11th Street
  Austin, TX  United States  78701-2483
• Managing Organizations:

  Texas Department of Transportation

  125 E. 11th Street
  Austin, TX  United States  78701-2483
• Project Managers:

  Odell, Wade

• Performing Organizations:

  Center for Transportation Research

  3925 W. Braker Lane
  Austin, TX  United States  78759
• Principal Investigators:

  Ferche, Anca

• Start Date: 20250925
• Expected Completion Date: 20280831
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Bridge design; Bridge foundations; Bridge substructures; Columns; Crashes; Impact loads; Load and resistance factor design; Load transfer; Structural connection
• Subject Areas: Bridges and other structures; Design; Highways;

Filing Info

• Accession Number: 01967818
• Record Type: Research project
• Source Agency: Texas Department of Transportation
• Contract Numbers: 0-7268
• Files: RIP, STATEDOT
• Created Date: Oct 2 2025 9:47AM