r - The Hong Kong Polytechnic University

The 5th Cross-strait Conference on Structural and Geotechnical Engineering (SGE-5)
Hong Kong, China, 13-15 July 2011
RECENT SEISMIC DESIGN AND RETROFIT STUDIES OF BRIDGES AT NCREE
ABSTRACT
K. C. Chang 1,2 , H. H. Hung 1 and K. Y. Liu 1
1
National Center for Research on Earthquake Engineering, Taipei, Taiwan
2 Department of Civil Engineering, National Taiwan University
Email: kcchang@ncree.narl.org.tw
Taiwan is located in a highly seismic active region of the world. Therefore, the structures in Taiwan suffer
frequently from earthquakes. Over the years, several earthquake events not only damaged the structures and
caused life and property losses, but also impeded the economic development of the country. As such, the seismic
design and retrofit of structures have become an essential issue for the sustainable development of Taiwan. As
part of this, the National Center for Research on Earthquake Engineering (NCREE) was officially established in
Taiwan in 1990. Thsis paper will introduce the researches at NCREE related to seismic design and retrofit of
bridges in recent years. These studies to be presented include the seismic retrofitting program, the rocking
behavior of bridge column with spread footing, and an on-site experiment of three bridge columns performed in
last year.
KEYWORDS
FRP, RC beams, strengthening, interfacial stresses, analytical solution.
INTRODUCTION
Taiwan is located along the western ridge of the Pacific Ocean earthquake belt and thus suffers frequently from
earthquakes. Frequent earthquakes have inevitably caused significant damages to the existing bridges in Taiwan.
The damages of the bridges due to earthquake not only lead to the loss of many innocent lives, but also interfere
with the rescue efforts, generating countless amount of cost to the society and economy. These circumstances
lead special attention to be given to seismic design and retrofit in Taiwan, especially after the devastating
Chi-Chi earthquake occurred in the central part of Taiwan on September 21, 1999. The National Center for
Research on Earthquake Engineering (NCREE) in Taiwan, which was officially established in 1990, has
continued to bring together academic resources and researchers to carry out joint projects to upgrade seismic
design and retrofit technologies to reduce life and property losses resulting from earthquake in the recently two
decades. This paper will introduce some latest researches at NCREE related to seismic design and retrofit of
bridges. These studies to be presented include a coordinated research program related to the seismic retrofitting
of RC bridge columns, two series of experiments focused on the rocking behavior of bridge column with spread
footing, and an on-site experiment of three bridge columns performed in last year.
SEISMIC RETROFIT STUDY OF RC BRIDGE COLUMNS
Background and Objectives
Significant amount of retrofit research and actual implementations to enhance the seismic performance of
existing bridges have been made in the United States, Japan and New Zealand after some major earthquakes
occurred in these countries. In order to make sure that if the retrofit methods used in these countries were also
effective for the existing RC bridge columns in Taiwan, a 4-years coordinated research effort on seismic retrofit
of existing RC bridge columns were established at the NCREE from 1998 to 2002. Major objectives of this
program were to develop effective seismic retrofit methods of existing bridges in Taiwan due to (1) inadequate
design strength, (2) inadequate confinement at potential plastic hinge region, (3) inadequate shear strength due
to large lateral steel spacing, and (4) lap-splicing in the plastic hinge zone. This coordinated research program
includes a master plan administrated by NCREE and seven coordinated projects handled by the investigators
from six universities and research institutions. The joint research effort has applied several retrofit techniques in
the tests, including the steel jacketing, reinforced concrete jacketing, and the advanced composite material
wrapping using the FRP. Results of this research program provided a domestic test database for seismic bridge
engineering applications and seismic retrofit guidelines for highway officials in Taiwan.
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