Abstract
From October 1st 2007, the new bridges on federal-aid funded projects are mandated to be designed by AASHTO LRFD Bridge Design Specifications. The resistance factors included in the current AASHTO specifications for foundation design are not all calibrated using field data. Plus, there is no calibrated resistance factor for serviceability-based design of drilled shafts. This paper presents a calibration of resistance factors for side resistance of drilled shafts in weak rock based on the statistical data collected from 19 O-cell tests in the mid-western United States. The field test data were used to determine the measured resistance at a settlement of 6.4mm (0.25 in.), which is commonly used in the bridge foundation design. The in-situ rock properties and the dimensions of drilled shafts were used to calculate the predicted resistance at the corresponding settlement using the FHWA method. The Monte Carlo method was selected to perform the calibration. Based on the normally distributed loads and the log normally distributed resistance from the test data, the side resistance factor was determined for a target reliability index of 3.0.
| Original language | American English |
|---|---|
| Title of host publication | Proceedings of the International Foundation Congress and Equipment Expo: Contemporary Topics in In-Situ Testing, Analysis, and Reliability of Foundations |
| DOIs | |
| State | Published - 2009 |
Keywords
- Calibrated
- Drilled shafts
- O-cell test data
- Serviceability-based design
- Side resistance factor
- Weak rock
DC Disciplines
- Engineering
- Civil Engineering