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Precast concrete bridge construction has been proved to be an efficient solution in accelerating bridge construction and minimizing traffic disruption. However, due to concerns with the seismic performance of such type of construction, its application in seismic regions is limited. This research presents results of the development of precast segmental post-tensioned concrete bridge columns for use in seismic regions. The developed bridge columns adopted unbonded post-tensioning systems to decrease
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prestress loss due to strong seismic events. In addition, to increase hysteretic energy dissipation, mild steel energy dissipation bars (ED bars) which are continuous across the
segment joints are added to the columns. Moreover, the ED bars are additionally unbonded at the critical joint to avoid premature fracture. 20485
A simplified analytical model for static pushover analysis and a three-
dimensional detailed finite element model for cyclic analysis of the proposed bridge
columns are developed in this research. In addition, a stiffness degrading hysteretic
model is proposed for response-history analysis. With the analytical models, a parametric
study is conducted to examine the seismic performance of the proposed columns with
different design parameters.
A two-phase experimental program is designed to verify the findings of the
analytical study and to address constructability issues of the proposed segmental columns.
The first phase focuses on testing of the ED bars at the critical joint. A methodology is
proposed to design the additional unbonded length for the bars, taking into account low
cycle fatigue of steel and progressive damage of bond. The second phase is testing of
seven large scale segmental column specimens. Each specimen has a foundation, four
precast column segments with hollow cross sections and a precast cap beam with a total
height of 5.7 m (18.7 ft). Four specimens were tested with cyclic loading while three
were tested with pseudo-dynamic loading. The test results show that three types of ductile
precast segmental columns are successfully developed with different hysteretic
characteristics in terms of energy dissipation, lateral strength and residual displacement.
ACKNOWLEDGEMENTS
First of all, I would like to thank to my advisor, Professor George C. Lee for his
guidance to this research and financial support over the past four years. I learned a great
deal from him not only from his knowledge and experiences in civil engineering but also
from the wisdom that he gained from his more than four decades of academic career. I
also would like to thank to Professor Amjad Aref, Professor Stuart S. Chen and Professor
Andre Filiatrault, my Ph.D. committee members, for their advice to this research. The
advice from Dr. Methee Chiewanichakorn on developing the analytical models for this
research is greatly acknowledged. In addition, I would like to thank to Dr. Il-Sang Ahn
for his advice to this research.
I would like to thank to Kuo-Chun Chang, Professor and Chairman of the
Department of Civil Engineering of the National Taiwan University, for his advice
throughout this research. His support is the key to the success of the experimental study
conducted in this research. I also would like to thank to Dr. Jui-Chen Wang for providing
valuable information and guidance on developing the new concepts for precast segmental
bridge columns for seismic regions. Mr. Ping-Hsiung Wang worked relentlessly throughout
the experimental study. Without his effort, the experiment could not have been completed in
only one year. Mr. Mu-Sen Tsai also played a significantly role in assisting the experimental
study. Thank for their effort.
I must thank to the Federal Highway Administration for financially supporting