Location

Chicago, Illinois

Session Start Date

4-29-2013

Session End Date

5-4-2013

Abstract

To achieve engineered designs with consistent levels of reliability, the Federal Highway Administration (FHWA) mandated that all new bridges initiated after October 1, 2007, including those founded upon drilled shafts, be designed according to the Load and Resistance Factor Design (LRFD) approach. As the first step in developing efficient regional LRFD procedures for drilled shafts, the Drilled SHAft Foundation Testing (DSHAFT) database was formulated. DSHAFT was aimed at assimilating high quality, historical drilled shaft test data from Iowa and the surrounding states, and it presently contains data from 41 drilled shaft load tests, 38 of which are O-cell load tests, along with subsurface information and structural details. Following an introduction to DSHAFT, several challenges associated with subsurface investigations, measurement of geomaterial properties, and test methods employed in current practice for drilled shaft capacity estimations are discussed. An improved procedure is then proposed featuring three different cases for establishing the equivalent top load-displacement response of drilled shafts. Using the proposed procedure and LRFD framework, it is shown that robust, more efficient regional LRFD resistance factors can be established for drilled shafts with a target displacement limit.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Seventh Conference

Publisher

Missouri University of Science and Technology

Publication Date

4-29-2013

Document Version

Final Version

Rights

© 2013 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 29th, 12:00 AM May 4th, 12:00 AM

An Investigation of Load and Resistance Factor Design of Drilled Shafts Using Historical Field Test Data

Chicago, Illinois

To achieve engineered designs with consistent levels of reliability, the Federal Highway Administration (FHWA) mandated that all new bridges initiated after October 1, 2007, including those founded upon drilled shafts, be designed according to the Load and Resistance Factor Design (LRFD) approach. As the first step in developing efficient regional LRFD procedures for drilled shafts, the Drilled SHAft Foundation Testing (DSHAFT) database was formulated. DSHAFT was aimed at assimilating high quality, historical drilled shaft test data from Iowa and the surrounding states, and it presently contains data from 41 drilled shaft load tests, 38 of which are O-cell load tests, along with subsurface information and structural details. Following an introduction to DSHAFT, several challenges associated with subsurface investigations, measurement of geomaterial properties, and test methods employed in current practice for drilled shaft capacity estimations are discussed. An improved procedure is then proposed featuring three different cases for establishing the equivalent top load-displacement response of drilled shafts. Using the proposed procedure and LRFD framework, it is shown that robust, more efficient regional LRFD resistance factors can be established for drilled shafts with a target displacement limit.