Date of Award

Spring 5-14-2016

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Civil Engineering

Advisor

William Davids

Second Committee Member

Melissa E. Landon

Third Committee Member

Eric N. Landis

Abstract

The University of Maine has developed concrete filled fiber-reinforced polymer (FRP) tubes (CFFTs) for use in bridge construction. A finite element model was previously developed to analyze these buried arch structures during construction, service live load, and ultimate load. Two shortcomings in that model include how the load distribution method and the soil reaction due to construction and service loads are modeled. There were two objectives to this research: to make a user-friendly software package to analyze a variety of buried arch structures and to improve the existing model to better predict the soil-structure interaction. Prototype software was developed complete with a graphical user interface using the existing model to allow engineers a tool to analyze a variety of materials, arch geometries, and soil conditions to predict the effect of diverse load cases. Changes to the model were planned to improve the model’s ability to capture the response of the soil due to arch deformation and produce more efficient arch designs. A Boussinesq stress distribution was used in the model to predict the dispersal of the load through the soil. Load distribution was investigated and compared to a previous experimental work and soil-continuum models to gain insight on the shortcomings of the existing load distribution model used in the analysis. The existing model used a horizontal soil-spring configuration with a nonlinear load-deflection relationship. Three changes to the soil-springs in the existing model were considered: radial soil-springs, friction angle soil-springs, and a three spring system. These alternative soil-spring models were implemented in place of the existing horizontal soil-springs and the arch internal moments and deflections were compared to the existing model and experimental results.

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