Date of Award

1985

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Civil and Environmental Engineering

Keywords

Engineering, Civil.

Rights

CC BY-NC-ND 4.0

Abstract

The stability of soil-steel structures is examined in this research. The analysis accounts for the behaviour and the induced stresses in soil and conduit during construction and loading. An analytical procedure using plane strain finite elements has been developed to study the different aspects of soil-steel structure instability. The conduit is represented by beam-column finite elements with the capability of accommodating plastic hinges when necessary. Interface elements of a spring type are used to represent the linkage between the two materials. Linear and constant strain elements are used to simulate the soil media, depending on the severity of the stress gradient of the structure. Two soil models are used to model the behaviour of the soil elements, a nonlinear elastic hyperbolic model as well as an elasto-plastic soil model. The parameters defining these models are obtained through triaxial compression tests. Geometric and material nonlinearities are considered in the analysis. Direct iterations are used to update the material properties. Failure in the soil elements is identified and followed by correction to the stress state in the whole structure. Instability of the structure, whether initiated by yielding of the soil mass above the conduit, excessive deflection of the conduit, buckling of the metallic conduit or by instability of the soil-steel structure is predicted. The results obtained by the computer program are checked with a series of laboratory tests carried out for this purpose. Comparisons with tests reported in other references and with Code Specifications are also made. Reasonable agreement is reached between the analytical and experimental results. Based on this agreement, a parametric study of the variables controlling the soil-steel structure stability is carried out. The height of soil cover, span and shape of the conduit, load type rigidity of the conduit walls and interface stiffness are among these variables.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1985 .D477. Source: Dissertation Abstracts International, Volume: 46-02, Section: B, page: 0592. Thesis (Ph.D.)--University of Windsor (Canada), 1985.

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