Sam Kafaji

ORCID Identifier(s)

0000-0002-6521-0469

Graduation Semester and Year

2023

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Civil Engineering

Department

Civil Engineering

First Advisor

Raad Azzawi

Abstract

The process of laying and tying conventional reinforcement is a time-consuming task when building a bridge deck, especially while ensuring the proper cover. To speed up the construction process, the bridge construction industry should look into replacing conventional reinforcing bars with steel fibers. This could be a significant breakthrough in bridge construction. Despite numerous experiments and research conducted on the bending strength of reinforced concrete decks, there are still several factors that require further exploration. This experiment focuses on utilizing steel fiber reinforced concrete (SFRC) in a multiple-span concrete bridge deck to investigate the opportunities of using SFRC as the main reinforcement and reducing construction time by eliminating the need for tying and tying reinforcement. SFRC does not require this, making the process much quicker. To evaluate the behavior of the SFRC decks, it was necessary to compare them to conventional reinforced concrete decks (RC) in terms of load-displacement, bending strength, ductility, crack behavior, and crack widths. In this study, two groups of concrete bridge decks were tested. The first group consisted of six decks, two of which were cast-in-place and reinforced with steel fiber as the main reinforcement, along with supplementary steel wire mesh (SFRC-CIP). The other two decks had similar reinforcement to the first two decks but were precast (SFRC-PC). These decks were compared with the last two cast-in-place decks reinforced by conventional steel bars designed per AASHTO LRFD (RC). The second group also had six decks, with two cast-in-place decks reinforced with steel fiber as the main reinforcement and supplementary GFRP mesh (SFRC-GFRP-CIP). The other two decks had similar reinforcement but were precast (SFRC-GFRP-PC). These decks were compared with the last two cast-in-place decks of this group that were reinforced by GFRP bars designed per AASHTO LRFD and ACI-440 code (GFRP). The study used concrete with a compressive strength of 4000 psi, and all decks were tested under flexural loads. Load-displacement curves (P-∆) were recorded as a tool to measure the ductility index (μE) (Spadea et al. and Hason 2021). The result showed that the flexural stiffness behavior of the SFRC concrete deck specimens was improved, and load-carrying capacity increased compared to RC and GFRP decks. Moreover, crack width and crack were reduced since the SFRC decks offer more concrete ductility than the RC and GFRP decks, meaning less future maintenance and corrosion. Therefore, utilizing steel fiber in concrete mixtures could be a significant step in speeding up bridge construction since it saves time for laying, tying, and verifying clear cover, in addition to increasing the lifespan of bridge decks.

Keywords

Steel fiber, GFRP, Concrete deck, Bending, Precast, Cast in place, Stress-strain, Load-deflection

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Comments

Degree granted by The University of Texas at Arlington

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