2279 - Probabilistic Approach for the Design of Drilled Shafts Socketed in Weak Rock in Oklahoma

Objective: The primary objective for the proposed work is to evaluate and calibrate current methods for design of drilled shafts in weak rock formations that are common in Oklahoma, and as appropriate, to develop additional load and resistance factor design (LRFD) methods. Background: Test measurements for different states can largely be attributed to differences in site characterization and construction practices. The proposed work offers the opportunity to continue improvement of design and construction of drilled shafts in shale and other weak rock for the broader geotechnical design community, fulfilling agency-specific objectives. Work plan: The proposed work plan uses reliability methods to achieve calibration of geotechnical resistance factors for axially loaded drilled shafts in shale and other weak rock. The research team will collect available empirical measurements of drilled shaft performance in shale and other weak rock, along with associated measurements from laboratory or in situ tests related to shaft performance. Once the research team establishes final resistance factors, they will propose design specifications along with a comprehensive technical report that will document the entire research effort. Anticipated Benefits: The proposed work will produce design guidelines that account for variability and uncertainty inherent in design of drilled shafts in shales. The new design guidelines will offer substantial cost savings for design and construction of transportation infrastructure by producing consistent reliability, and improved estimates for foundation performance. The FHWA is currently working to develop guidance regarding application of post-grouting for drilled shafts, including ways to address improved reliability as a result of post-grouting. The proposed work will facilitate rapid adoption of such guidance by ODOT once it is completed. Implementation: Implementation of the proposed work is a relatively straightforward matter of adopting the design specifications deliverable and revising current ODOT design documents to include the proposed specifications. Expected Deliverables: Provide proposed design specifications and associated commentary prepared in a format compatible with current ODOT design documents. All load test measurements (e.g., raw strain gauge readings, spreadsheets, etc.) and geotechnical reports documenting laboratory and field test measurements, etc. will be provided in electronic format. The entire project will be documented as a comprehensive technical report that provides support and justification for the recommended design methods and resistance factors. Time Schedule: The project will last at least 18 months or, considering the time required to design and execute additional load testing for the project, as long as 36 months. Budget and Justification: The proposed budgets provided have been developed to include all costs associated with developing the proposed design specification, including costs for performing proposed site characterization and field load testing as described in the proposal. Budgets for load testing represent general estimates for conducting load tests for “typical shafts” since specific requirements for load testing (e.g., shaft depth) cannot be established without more detailed information regarding the load test sites. More refined cost estimates for these expenses can be developed if additional information regarding sites can be determined.

Language

• English

Project

• Status: Completed
• Funding: $580,000
• Contract Numbers:

  SPRY-0010(082)RS

• Sponsor Organizations:

  Oklahoma Department of Transportation

  200 NE 21st Street
  Oklahoma City, OK  United States  73105
• Managing Organizations:

  Oklahoma Department of Transportation

  200 NE 21st Street
  Oklahoma City, OK  United States  73105
• Project Managers:

  Jesse, Shon

• Performing Organizations:

  University of Missouri, Kansas City

  Department of Civil Engineering
  5100 Rockhill Road, Flarsheim Hall
  Kansas City, MO  United States  64110
• Principal Investigators:

  Loehr, Erik

• Start Date: 20171006
• Expected Completion Date: 20210930
• Actual Completion Date: 20220930

Subject/Index Terms

• TRT Terms: Geotechnical engineering
• Subject Areas: Geotechnology; Research; SOIL MECHANICS;

Filing Info

• Accession Number: 01656366
• Record Type: Research project
• Source Agency: Oklahoma Department of Transportation
• Contract Numbers: SPRY-0010(082)RS
• Files: RIP, STATEDOT
• Created Date: Jan 8 2018 3:26PM