• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.823-828
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• 2002

Lap splice in plastic hinge region of RC bridge piers is inevitable because of the constructional joint between footing and column. RC circular columns with lap-splice in plastic hinge region are widely used in Korean highway bridges. It is, however, believed that there we not many experimental research works for nonlinear behavior of these columns subjected to earthquake motions. This study has been peformed to verify the effect of lap splice and confinement steel ratio for the seismic behaviour of reinforced concrete bridge piers. Quasi-static test have been done to investigate the physical seismic performance of RC bridge piers, such as displacement ductility.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.879-884
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• 2002

The objective of this study is to investigate the seismic capacity of the non-seismically detailed RC bridge piers before and after applying a seismic retrofitting method using stainless steel wire mesh. Total nine circular section RC piers were constructed. Different lap splice longitudinal reinforcement details were adapted for four specimens and various types of stainless steel wire mesh were applied for the remaining five specimens. Harmonic cyclic lateral load was applied on each specimen under a constant axial load. The test results indicated that the existing circular piers have low seismic capacity while the stainless steel wire mesh retrofitting method improves the seismic capacity considerably. In addition, test results revealed that the circular section piers could have a considerable amount of ductility if longitudinal bars are not lap-spliced in potential plastic hinge zone. Based on this experimental study it could be concluded that the seismic performance, that is ductility and energy absorption capacity, of the non-seismically detailed RC bridge piers would be increased by applying the stainless steel wire mesh seismic retrofitting method.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.697-707
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• 2004

Most bridge piers were practically designed and constructed with lap spliced longitudinal reinforcing steels before the 1992 seismic design provisions of Korea Bridge Design Specification were implemented. It has been known that lap splice of longitudinal reinforcement in the plastic hinge region is not desirable for seismic performance of RC bridge piers. The objective of this research is to evaluate the seismic performance of existing circular reinforced concrete bridge piers by the Quasi-static test and to propose the need of seismic retrofit of existing bridge piers through the damage level. Test specimens were nonseismically designed with the aspect ratio 4.0 which could induce the flexural failure mode. It was confirmed from this experiment that significant reduction of seismic performance was observed for test specimens with lap spliced longitudinal reinforcing steels. Pertinent seismic retrofit was determined to be needed for existing RC bridge piers with the lap-spliced of $50\%$ longitudinal reinforcing steels.

• Journal of the Korea Concrete Institute
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• v.19 no.1
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• pp.19-26
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• 2007

Until recently Korea is considered to be immune from the earthquake hazard because it is located for away from the active fault. However, we have noticed that recent strong earthquakes inflicted enormous losses on human lives and nation's economy all over the world. Hence, there has been raised the importance of the earthquake resistant design for various infrastructures. In this research, new methodologies for the seismic design and performance assessment of reinforced concrete(RC) bridge pier were proposed from experimental results of 82 circular RC bridge piers and 54 rectangular RC bridge piers tested in domestic and aboard. New seismic design method was based on the concept of the limited ductile design, which could be practically used for low or moderate seismic regions like Korea. Further study for the seismic safety of RC bridge piers was carried out to enhance the seismic performance of aged RC bridge piers, which were designed and constructed before implementing the 1992 seismic design provision in Korea. New formula for the seismic performance assessment of RC bridge piers was proposed and practically used for the decision on the need of repair and retrofit of many aged RC bridge piers.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.89-92
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• 2005

Recently there have been occurred many loss of life and extensive damage to social infrastructures due to moderate and strong earthquakes all over the world. In this research, major design factors have been evaluated for the establishment of the rational seismic design code of rectangular RC bridge piers. It was concluded from this study that the axial force ratio and the longitudinal steel ratio should be the most important influencing design parameter for the seismic displacement ductility. However those parameters are not considered in the confinement steel ratio of the KHBDS. Thus, the objective of this study is to propose a rational design equation for transverse reinforcements of rectangular RC bridge piers. New confinement steel ratio is proposed by introducing the effect of the axial force and the longitudinal steel to the current KHBDS. It is thought that these new codes could release the rebar congestion problem in the plastic hinge region of RC bridge piers which contribute to the enhancement of constructibility and economization for RC bridge construction.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.6
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• pp.1-12
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• 2008

As internal and external seismic experiment results, the seismic performance of RC bridge piers is largely dependent on the ratio of lap-spliced bars to all longitudinal reinforcing bars in plastic hinge regions, and confining effects of transverse reinforcements. Capacity and displacement ductility of non-seismically designed existing RC piers are reduced by lap splices in plastic hinge regions. The provision for the lap splice of longitudinal reinforcing bars was not specified in KBDS (Korean Bridge Design Specifications) before the implementation of 1992 seismic design code, but the ratio of lap-spliced bars to all longitudinal reinforcing bars in plastic hinge regions is restricted to 50% in the 2005 version of KBDS. This paper presents a seismic assessment of RC piers at lap-splicing ratios of 0%, 50%, and 100%. Through a comparison of experimental and analytic results of RC piers, we introduce an appropriate ultimate strain of confined concrete in plastic hinge regions with lap-splices, and propose a method for estimating displacement ductility ratios of non-seismically designed existing RC piers using fiber element analysis.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.203-210
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• 2002

The past bridge design specifications of Korea didn't include 1imitation on the amount of lap splices in the plastic hinge zone of piers, and so do current specifications. But these specifications include just limitation on the minimal length of lap splices. Thus, a large majority of non-seismically designed bridge piers may have lap splices in plastic hinge zone. In this study, model pier was selected among existent bridge piers whose failure mode is complex shear-flexure mode. Full scaled RC pier models whose aspect ratio is about 2.67 were constructed and quasi static test according to the drift level history was implemented. From the test results, effect of the lap splices on the seismic performance of bridges piers was analyzed, and the seismic capacity of the model bridges was evaluated by capacity spectrum method.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.218-221
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• 2006

The past Korean Bridge Design Specifications have no limitation on the amount of lap splices of longitudinal bars in the plastic hinge zone of piers. A majority of bridge piers which have been non-seismically designed might have some lap splices in plastic hinge zone. Also a number of those piers in Korea have a low aspect ratio(height/section area). So, some problems such as low ductility behavior may happen. In this study, the real pier which was non-seismically designed and has a low aspect ratio was selected for the quasi-static tests. Two groups of full scaled RC pier models of which aspect ratios are about 2.26 and about 2.67 were fabricated. And then, quasi-static tests according to the drift level history method were implemented. From the test results, the failure of these test specimens have been shown in the complex shear-flexural or shear modes. The low aspect ratio and the lap splice have largely influenced on the seismic performance of bridge piers.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.877-882
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• 2001

Lap splice in plastic hinge region of RC bridge piers is inevitable because of the constructional joint between footing and column. RC circular columns with lap-splice in plastic hinge region are widely used in Korean highway bridges. It is, however, believed that there are not many experimental research works for nonlinear behavior of these columns subjected to earthquake motions. This study has been performed to verify the effect of axial force, lap splice and confinement steel ratio for the seismic behaviour of reinforced concrete bridge piers. Quasi-static test have been done to investigate the physical seismic performance of RC bridge piers, such as displacement ductility and enemy absorption.

• Journal of the Korea Concrete Institute
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• v.11 no.5
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• pp.107-118
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• 1999

10 RC bridge piers have been made on a 1/3.4 scale model, and six piers of them were retrofitted with glassfiber. The have been tested in the quasi-static cyclic load so as to investigate their seismic enhancement before and after retrofitting with glassfibers. The objective of this experimental study is to investigate how to strength the ductility of reinforced concrete bridge piers which have been nonseismically designed and constructed in Korea before 1992. Important test parameters are axial load, load pattern, retrofit type. Glassfiber sheets were used for retrofitting in the plastic hinge region of concrete piers. The nonlinear behavior of bridge columns have been evaluated through their yield and ultimate strength, energy dissipation, displacement ductility and load-deflection characteristics under quasi-static cyclic loads. It can be concluded from the test that concrete piers strengthened with glassfibers have been enhanced for their ductile behavior by approximate 50%.