Document Type

Thesis - Open Access

Award Date

2020

Degree Name

Master of Science (MS)

Department / School

Civil and Environmental Engineering

First Advisor

Mostafa Tazarv

Keywords

Accelerated Bridge Construction, Bridge Columns, Ductility, Mechanical Bar Couplers, Seismic Drift Capacity, Seismic Drift Demand

Abstract

Reinforcement continuity in concrete members is traditionally achieved through lap splicing. Mechanical bar splices are an alternative to traditional lap splices. Mechanical bar splices utilize mechanical devices known as bar coupler to connect the ends of reinforcing bars. Bar couplers are common in accelerated bridge construction applications at non-critical members but are not allowed in the plastic hinge region of bridge columns probably due to a lack of knowledge on how they affect seismic performance of columns. A comprehensive analytical study was carried out to determine how bar couplers used at the base of bridge columns affect: 1) column lateral drift capacity, and 2) column lateral drift demand. Modeling methods were proposed and validated against test data. More than 400 pushover analyses and 540 nonlinear dynamic analyses were carried out on mechanically spliced columns using the verified models. The results from the pushover analyses showed that columns with couplers may reduce the displacement ductility capacity up to 45% when compared to conventional cast-inplace columns. A trend between coupler length/rigidity and ductility capacity was established. The displacement capacity of bridge columns decreased as the coupler length and rigidity increased. Furthermore, the results from the nonlinear dynamic analyses showed that couplers have minimal effect on the seismic drift demand of concrete bridge columns when incorporated at the base. A maximum deviation of 7.23% was found when spliced column response was compared to that of the cast-in-place reference column. In general, it was observed that columns spliced with short couplers exhibited slightly higher displacement demands compared with conventional unspliced columns while columns spliced with long couplers showed slightly lower displacement demands compared to conventional columns. This may be due the fact that columns with longer couplers are slightly stiffer than conventional columns thus their displacement demands are lower.

Library of Congress Subject Headings

Reinforcing bars.
Reinforced concrete construction -- Earthquake effects.
Columns, Concrete -- Design and construction.
Concrete bridges -- Design and construction.
Earthquake resistant design.

Format

application/pdf

Number of Pages

105

Publisher

South Dakota State University

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Rights Statement

In Copyright