DEVELOPMENT OF PRACTICAL PROCEDURES FOR DESIGN OF DRILLED SHAFTS TO SUPPORT SOUND WALLS |
 This study was performed under sponsorship of
the Virginia Transportation
Research Council (VTRC). The Principal Investigator was Dr. Michael Duncan
of Virginia Tech. The objective was to investigate current design methodology
for sound wall (sound barrier) foundations in Virginia. These foundations are
usually designed by contractors and subsequently verified by the
Virginia Department of Transportation
(VDOT) personnel. In most cases the design is based on Broms theory for
ultimate capacity of eccentrically loaded drilled shaft in cohesionless soil,
using friction values estimated from the Standard Penetration Test (SPT) blow
counts. VDOT was concerned with the accuracy of current design procedures and
associated issues of safety and economy.The research included a review of Broms and Brinch-Hansen theories for the ultimate load capacity of drilled shafts, field load tests in various soils in Virginia, laboratory measurements of soil properties, and a parametric study to assess the effect of various factors on the required shaft length. An Excel spreadsheet named LCAP was developed to automate design calculations for sound wall foundations. This spreadsheet provides an effective tool for performing required computations and applying engineering judgement. Results from field tests performed on 8 and 9 inch diameter drilled shafts were used to producep-y curves for partially saturated silty and clayey soils at five locations in Virginia. An Excel spreadsheet named PYSHEET, developed in this study, incorporates the expressions for Brinch-Hansen’s Kq and Kc parameters and can be used to calculate p-y curves for piles and drilled shafts of any size in cohesive-frictional soils.
The research on drilled shaft sound wall foundations is summarized in the following three final reports:
To obtain copies of these reports please contact
Dr. Michael Duncan
(VPI) Last modified on Thursday, 10-Feb-2000 18:02:21 EST. |
