Synthesis of Information Related to Highway Problems. Topic 36-12. Use of Rock-Socketed Shafts for Highway Structure Foundations

Drilled shafts socketed into rock are widely used as highway bridge foundations. There are several challenges for design engineers in the use of these shafts. The first is analysis and design of rock-socketed shafts under lateral loading. It has been a customary practice to adopt the techniques developed for laterally loaded piles in soil to solve the problem of rock-socketed shafts under lateral loading. This practice has created erroneous designs and often ends with excessive socket length. There exist several analysis and design methods specifically for rock-socketed shafts under lateral loading, including those by Carter and Kulhaway (1992), Reese (1997) and Zhang et al (2000); their application in practice remains very limited because they are still at early stages and need additional field test data to validate them. The second is the determination of the axial load capacity of rock-socketed shafts. The axial load capacity of a rock-socketed shaft consists of the side shear resistance and the end bearing capacity. For the side shear resistance, much research has been conducted and guidelines are available for determining it. For the end bearing capacity, however, design engineers often have difficulty in determining it. Therefore, in many cases, the end bearing capacity of rock-socketed shafts is ignored in design. Since the construction cost of shafts in rock is very high, ignoring the end bearing capacity leads to overdesign and significant waste of money. There are different methods for estimating the end bearing capacity of rock-socketed shafts and they often give very different values.

• Record URL:
  http://www.trb.org/TRBNet/ProjectDisplay.asp?ProjectID=92

Language

• English

Project

• Status: Completed
• Funding: $12000.00
• Contract Numbers:

  Project 20-05, Topic

• Sponsor Organizations:

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590

  American Association of State Highway and Transportation Officials (AASHTO)

  444 North Capitol Street, NW
  Washington, DC  United States  20001

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001
• Project Managers:

  Williams, Jon

• Performing Organizations:

  University of Wyoming, Laramie

  1000 E University Avenue, Department 3295
  Laramie, WY  United States  82071
• Principal Investigators:

  Turner, John

• Start Date: 20041101
• Expected Completion Date: 0
• Actual Completion Date: 20060922
• Source Data: RiP Project 9800

Subject/Index Terms

• TRT Terms: Bridge foundations; Design; Design engineering; Highway bridges; Lateral supports; Load factor; Research projects; Rocks; Shaft sinking
• Subject Areas: Bridges and other structures; Construction; Design; Highways; I30: Materials;

Filing Info

• Accession Number: 01463096
• Record Type: Research project
• Source Agency: National Cooperative Highway Research Program
• Contract Numbers: Project 20-05, Topic
• Files: RIP, USDOT
• Created Date: Jan 3 2013 2:16PM