Alternative Title

Paper No. 1.36

Location

St. Louis, Missouri

Session Start Date

3-8-1998

Session End Date

3-15-1998

Abstract

A pedestrian bridge was constructed between two portions of a hospital in Southern California. Potentially liquefiable soils were present to a depth of about 72 feet below the ground surface. Because of the liquefiable soils, the bridge was to be supported on 30- inch-diameter cast-in-place piles drilled to a depth of approximately 90 feet below the ground surface. A test pile was constructed to confirm the soil capacities for the bridge. An Osterberg Load cell (O-cell) was placed near the middle of the test pile, and the downward load capacities of the deeper soils (below the elevation of potentially liquefiable soils) were tested using the upper portion of the pile to provide reaction. Instrumentation of the test pile consisted of four pairs of vibrating wire strain gages mounted on the pile reinforcing cage at four depths. The strain gages were connected to a data acquisition unit used to record data during the pile load test. A pair of tell-tale rods connected to electronic dial gages monitored the movement of the lower plate of the O-cell. Another pair of tell-tale rods was used to monitor the movement of the top of pile during the test while a third pair of tell-tale rods was used to monitor the compression of the upper portion of the pile. The pile load test was successful in confirming the predicted pile capacities, and the production piles were installed. The Osterberg Load cell was an economical method of testing the pile for this particular application.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Fourth Conference

Publisher

University of Missouri--Rolla

Publication Date

3-8-1998

Document Version

Final Version

Rights

© 1998 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Osterberg Load Cell Testing of a Deep Reinforced Concrete Pile

St. Louis, Missouri

A pedestrian bridge was constructed between two portions of a hospital in Southern California. Potentially liquefiable soils were present to a depth of about 72 feet below the ground surface. Because of the liquefiable soils, the bridge was to be supported on 30- inch-diameter cast-in-place piles drilled to a depth of approximately 90 feet below the ground surface. A test pile was constructed to confirm the soil capacities for the bridge. An Osterberg Load cell (O-cell) was placed near the middle of the test pile, and the downward load capacities of the deeper soils (below the elevation of potentially liquefiable soils) were tested using the upper portion of the pile to provide reaction. Instrumentation of the test pile consisted of four pairs of vibrating wire strain gages mounted on the pile reinforcing cage at four depths. The strain gages were connected to a data acquisition unit used to record data during the pile load test. A pair of tell-tale rods connected to electronic dial gages monitored the movement of the lower plate of the O-cell. Another pair of tell-tale rods was used to monitor the movement of the top of pile during the test while a third pair of tell-tale rods was used to monitor the compression of the upper portion of the pile. The pile load test was successful in confirming the predicted pile capacities, and the production piles were installed. The Osterberg Load cell was an economical method of testing the pile for this particular application.