Degree Type

Thesis

Date of Award

2019

Degree Name

Master of Science

Department

Civil, Construction, and Environmental Engineering

Major

Civil Engineering

First Advisor

Behrouz Shafei

Abstract

During bridge construction, closures have significant impacts on traffic flow for the public. To alleviate this impact, the presence of precast elements is being introduced in the design and construction of bridges, which would increase the efficiency of construction and convert month-, or even year-, long closures into a matter of weeks, or perhaps even days. This strategy, known as accelerated bridge construction (ABC), is growing in popularity within the bridge community and is gaining traction for research projects to investigate how the construction of bridge elements can be expedited.

One such element being investigated is the integral abutment. This structural connection for bridges was introduced to eliminate the need for expansion joints between the substructure and superstructure, where the presence of water and other deteriorating chemicals caused long-term and frequent maintenance issues. The integral abutment alleviates the need for the expansion joint by having the superstructure rigidly connected to the foundation to cause the two elements to act together in response to traffic loads, as well as thermal expansions and contractions. Due to this area needing to be heavily reinforced, congestion issues arise when attempting to apply ABC methods.

Moreover, the construction tolerances and weight of the integral abutments cause some problems for ABC projects. Addressing these issues was the main motivation for the research performed in this thesis in which the use of couplers and ultra-high-performance concrete, while applying ABC techniques, is investigated. The foundation element of focus was the pile cap, while the superstructure element investigated was the integral diaphragm, which consists of the deck and cast-in-place girder. Three different connection details were investigated such as grouted reinforcing bar coupler, pile coupler, and UHPC-Joint. The strength and durability of the connection details were evaluated through full-scale laboratory testing that applied simulated thermal loads and live loads. Strain gauges were used to capture the development and strength of the specimen and connecting materials, and displacement transducers monitored the propagation and magnitude of precast joint openings between the integral diaphragm and pile cap to evaluate the durability of the connection details. The results of these tests were compared to the control specimen tested in the previous phase of the project. (Hosteng, Phares, & Redd, 2016) A separate set of three-dimensional finite element (FE) simulations were also conducted to complement the findings obtained from the laboratory experiments. The effect of the number of bar couplers on enhancing the performance of the abutment connections was evaluated in detail. The outcome of this study resulted in high quality results for integral abutment connections for ABC applications, not only through laboratory test results, but also by finite element simulations that could aid the bridge engineering community in the progression towards implementation of this connection area for future use.

Copyright Owner

Austin James DeJong

Language

en

File Format

application/pdf

File Size

219 pages

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