Location

St. Louis, Missouri

Session Start Date

6-1-1993

Abstract

Two of the caissons supporting the 26-story IBM office building were instrumented to evaluate the load transfer mechanism from caissons to the surrounding soil and rock. These drilled shafts extended through loose alluvial stratum, a stratum of dense sands and silts, a disintegrated rock stratum, and were founded in the underlying Amphibolite bedrock. Evaluation of mobilized skin friction and end bearing for one of the caissons are presented in this study. Instrumentation consisted of vibrating wire total load cells and embedded strain gauges. Total load cells were installed at the bottom of the caissons to measure the end bearing pressure. Embedment strain gauges were installed in groups of three in the middle of the general strata and at the approximate level of strata change to evaluate skin friction. In-situ measurements from the gauges were recorded during the construction of the building. From these strain gauge readings load distribution with depth, the average skin friction in each stratum and end bearing pressure were calculated and presented. Finally, these mobilized values were compared with the initial design parameters and the performance of the foundation was evaluated.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Third Conference

Publisher

University of Missouri--Rolla

Publication Date

6-1-1993

Document Version

Final Version

Rights

© 1993 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Instrumented Caissons at the IBM Building, Baltimore

St. Louis, Missouri

Two of the caissons supporting the 26-story IBM office building were instrumented to evaluate the load transfer mechanism from caissons to the surrounding soil and rock. These drilled shafts extended through loose alluvial stratum, a stratum of dense sands and silts, a disintegrated rock stratum, and were founded in the underlying Amphibolite bedrock. Evaluation of mobilized skin friction and end bearing for one of the caissons are presented in this study. Instrumentation consisted of vibrating wire total load cells and embedded strain gauges. Total load cells were installed at the bottom of the caissons to measure the end bearing pressure. Embedment strain gauges were installed in groups of three in the middle of the general strata and at the approximate level of strata change to evaluate skin friction. In-situ measurements from the gauges were recorded during the construction of the building. From these strain gauge readings load distribution with depth, the average skin friction in each stratum and end bearing pressure were calculated and presented. Finally, these mobilized values were compared with the initial design parameters and the performance of the foundation was evaluated.