ORCID Identifier(s)

0000-0002-1947-5116

Graduation Semester and Year

2019

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering

Department

Civil Engineering

First Advisor

Ali Abolmaali

Abstract

This research investigates the structural and industrial possibility to create a new type of concrete pipes called synthetic fiber reinforced thin-walled concrete pipes, which would be lighter, cheaper, and more durable than what is currently in use while still providing a pipe product much less dependent upon installation conditions than the very flexible metal and plastic pipes in the American market. The idea is to reduce the thickness and reinforcement of the current reinforced concrete pipes to increase their deflection before failure and control the crack formation and width by using synthetic fibers. The flexibility of these pipes will enable them to use the passive pressure of surrounding soil and in turn, relieves the pipe of the burden of carrying the soil load through moment and shear in the pipe wall and allows it to perform primarily under compressive stress in the pipe wall. To fulfill the research goal two phases of experimental investigations was performed. The first phase was to understand the behavior of synthetic fiber reinforced TWCPs in Industrial scale pipe production using a common industrial concrete mix design. In this phase, 44 pipes were created and TEB test was performed on all the pipes. deformation curve for all tested specimens was extracted and the cracking behavior of the pipes with and without using synthetic fibers was observed. The second phase was to perform experimental study on crack development in synthetic fiber reinforced concrete specimens. In this phase, 12 beam specimens were created using ASTM 1609 recommendations. The beams were tested in two groups of six beams under three and four-point bending test setup. Crack width was measured using two-dimensional digital image correlation (DIC) method. Finite element models were created to develop material model for synthetic fiber reinforced concrete which can mimic the results of the tests. During the numerical study a reliable crack width measurement method was introduced using the distribution of plastic tensile strain in FE model. The last phase of numerical study was to create soil pipe interaction models to evaluate the behavior of the pipes and their crack widths under soil backfill. A parametric study was performed which led to development of equations to find the amount of crack width as well as the design graphs.

Keywords

Synthetic fiber reinforced concrete pipes, Three-Edge Bearing test, Crack width measurement, Digital Image Correlation method, Finite element analysis, Concrete Damage-Plasticity Model, Soil-pipe interaction

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

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