Date of Award

8-2008

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Civil Engineering

Advisor

Juang, Charng-Hsein

Committee Member

Roth , Mary J.S.

Committee Member

Andrus , Ronald D.

Committee Member

Hill, Jr. , Hoke S.

Abstract

In this dissertation, a framework for a fully-probabilistic analysis of the potential for building serviceability damage induced by an excavation in soft clays is established. This analysis framework is established based on the concept of a serviceability limit state where the resistance is represented by the capacity of a building to resist serviceability damage, and the loading is represented by the demand on a building due to excavation-induced ground movements. In this study, both the resistance and the loading are treated as a random variable; the resistance is characterized empirically based on a database of the observed building performance while the loading is estimated for a specific case using semi-empirical models that were created with the results of finite element analysis and field observations.
A simplified procedure is developed for estimating the loading on a building induced by an excavation. In this simplified procedure, the loading is expressed in terms of damage potential index (DPI) that is based on the concept of principal strain. On the other hand, the resistance as a random variable is characterized based on observed building performance, also in terms of the DPI. The uncertainties of both the resistance and the loading are fully characterized in this dissertation study to enable a fully probabilistic analysis. The developed framework for the fully-probabilistic assessment of the potential for excavation-induced building damage is demonstrated with the well-known TNEC case history.
Finally, since the observational method is commonly applied to the design and construction of excavation systems, a simplified scheme for updating the soil parameters (and consequently DPI) based on the observations of the maximum wall deflection and ground settlement is developed. This updating scheme is demonstrated with an excavation case history and shown to be an effective technique for monitoring the damage potential of buildings adjacent to an excavation.
The developed framework allows for fully-probabilistic assessment of the potential of building damage induced by an excavation, and thusly, provides engineers with a more transparent assessment of the risk associated with a particular excavation design and construction. Furthermore, with the observational method, the potential for excavation-induced serviceability damage can be reassessed as the excavation proceeds. With this approach, the excavation system can be monitored as the excavation proceeds and necessary measures can be taken to prevent damage to buildings adjacent to the excavation.

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