• Earthquakes and Structures
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• 제26권4호
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• pp.269-283
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• 2024

When a reinforced concrete (RC) structure is exposed to a corrosive environment for an extended period of time, the material qualities deteriorate, resulting in a loss in seismic performance. Engineered Cementitious Composites (ECC) have been used to reinforce the corroded RC structure, which can achieve reinforcement effectiveness for a small change in cross-section size. In this work, finite element models of unjacketed RC pier and ECC jacketed pier were established and verified by experimental tests, with the buckling effect of longitudinal reinforcement considered. Compared with the unjacketed pier, the displacement of the pier top of the ECC jacketed pier was reduced by about 9.52% under earthquake action. In the case of moderate and major earthquakes, the probability of exceedance of ECC jacketed pier is significantly reduced. For the case of rare earthquake loading, with the ECC jacket, the e of the pier experiencing serious damage and complete damage states is reduced by 10.29% and 29.78%, respectively.

• 한국산학기술학회논문지
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• 제8권2호
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• pp.333-338
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• 2007

내부 구속 중공 RC 교각은 교각의 강성 및 연성의 증가를 목적으로, 중공 RC 교각의 중공 면에 내부 구속력을 제공하는 강관을 삽입한 교각이다. 본 연구에서는 내부 강관의 두께를 변화시켜 내부 구속 중공 RC 교각의 거동 특성을 파악하였으며, 거동 특성을 파악하기 위한 평가 방법으로는 안전율, 연성능력, 재료비, 교각의 총중량 등으로 평가하였다. 해석적 연구 결과, 내부 구속 중공 RC 교각의 내부 강관 두께는 최소 필요 두에를 적용하는 것이 가장 효과적인 것으로 나타났다. 또한, 중공 단면에 대한 교각의 자중감소 효과를 확인할 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.17-20
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• 2005

Moment-curvature relation of RC pier is influenced greatly in occurrence form of crack and difference is happened according to consideration existence and nonexistence of tension stiffening effect. However, studies considering these is very insufficient misgovernment. Also, it is sometimes unavoidable lap splice of axial reinforcement in plastic hinge region of RC piers. However, specific design standard about lap splice of axial reinforcement is unprepared real condition and study about effect that lap splice of axial reinforcement get in occurrence form of crack is insufficient misgovernment. Therefore, in this paper, experiments are performed with hollow RC piers that do lap splice of axial reinforcement by main variable. And this study present analytical method about moment-curvature relation of hollow RC pier that consider tension stiffening effect and analyze effect that lap splice of axial reinforcement gets in occurrence form of crack. Analytic method of moment-curvature relation of RC pier that present in this study shows very similar motion with experiment result and crack interval of RC pier is suffering dominate impact in the augmented reinforcement amount by lap splice and average crack interval decreases as lap splice ratio increases.

• 한국방재학회 논문집
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• 제10권4호
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• pp.17-24
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• 2010

중공 RC 교각은 중실 RC 교각에 비해 자중의 감소 및 재료 절감에 대한 장점을 가진다. 그러나 중공 RC 교각은 안쪽면의 취성파괴로 인하여 낮은 연성 거동을 할 가능성이 있다. 이러한 문제점을 해결하기 위해 중공 부재 내의 콘크리트 3축 구속 상태로 존재하게 하는 내부 구속 중공 RC 교각이 개발되었다. 본 연구에서는 내부 구속 중공 RC 교각의 매개변수(중공비, 내부강관두께, 횡방향 철근 간격, 종방향 철근 개수, 콘크리트 강도)변화에 따른 안전율, 연성도, 재료비 및 교각 총 중량에 대한 거동 특성을 파악하였다. 매개변수 변화에 따른 내부 구속 RC 교각의 거동 특성 결과 내부 강관 두께는 최소한의 내부강관 두께를 적용하는 것이 효과 적인 것으로 파악되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.25-28
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• 2004

Many highway bridges in Korea need seismic retrofit because only one decade has passed since the seismic design criteria was introduced. In this experimental study, the effectiveness of base isolation bearings was discussed for the seismic retrofit of the highway bridges. Four real scale RC pier specimens were constructed for the test. These RC piers didn't have seismic details. Except for one RC pier for the pilot test, three types of bearings such as Pot bearing, Rubber bearing (RB), Lead-rubber bearing (LRB) were applied to the other RC piers respectively. The RC pier with Pot bearing means current state of the prototype bridge that is not retrofitted seismically. And two RC piers with RB or LRB mean assumed states of the prototype bridge that are retrofitted seismically. To simulate dynamic behavior of these RC piers under earthquake loads, Pseudo-dynamic test method was used.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.59-62
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• 2007

The hollow RC(Reinforced concrete) pier has decrease of weight and reduced of materials compared to solid RC pier. However, the hollow RC pier shows a low ductile behavior due to brittle failure of inside concrete. To overcome this problem, the internally confined hollow reinforced concrete column has been developed. In this study, the behavior of internally confined hollow RC piers were evaluated with safety ratio, ductility, total material cost, the total weight of the pier, etc. The chosen parameters for the study are hollow ratio, thickness of internal steel tube, intervals between vertical re-bars, numbers of horizontal re-bars, and strength of concrete.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.341-348
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• 2000

The existing solid circular RC pier without seismic detailing is found to have poor ductility due to the premature bond failure of lap spliced longitudinal bars. The steel-jacket was introduced to prevent this unexpected type of failure. The nonlinear behavior and he seismic performance of the retrofitted pier were examined through the scale model test and compared with those of existing one. It is confirmed from the test results that the steel-jacket retrofitting can be used as an measure to improve seismic performance considerably.

• 한국지진공학회논문집
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• 제19권3호
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• pp.109-120
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• 2015

The purpose of this study was to investigate the performance of new hollow reinforced concrete (RC) bridge pier sections with triangular reinforcement details. The proposed triangular reinforcement details are economically feasible and rational and facilitate shorter construction periods. A model of pier sections with triangular reinforcement details was tested under quasi-static monotonic loading. As a result, proposed triangular reinforcement details was equal to existing reinforcement details in terms of required performance. In the companion paper, the parametric study for the performance assessment of new hollow RC bridge pier sections with triangular reinforcement details is performed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.617-622
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• 2000

In this study, effective compressive strength and nodal zone of Strut-and-Tie Model are studied to propose a new design method for RC T-type pier coping for prevention of sudden brittle failure. The coping which transmits loads of bridge to pier should be properly designed to retain ductile behavior. In order to carry out this proper design using STM, tie must yield before concrete fails, and a stress at strut should not exceed a certain effective stress. Therefore, reasonable determination of the effective compressive strength of strut by considering stress states at the nodal zone exactly is very important. Since conventional STM is applied under assumption that all nodes are under hydrostatic stress state, actual non-hydrostatic stress state in nodal zone caused by geometrical characteristics, loading conditions, support conditions of structures can not be considered properly. In order to apply STM for design of RC T-type pier coping, the non-hydrostatic stress state of nodal zone is considered and effective compressive strength is proposed. Then, a new design method of RC T-type pier coping which applies the principle of superposition to obtain optimum ductile behavior is rationally designed.

• Smart Structures and Systems
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• 제4권3호
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• pp.319-342
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• 2008

Identification of the nonlinear hysteretic behavior of a reinforced concrete (RC) bridge pier subjected to earthquake loads is carried out based on acceleration measurements of the earthquake motion and bridge responses. The modified Takeda model is used to describe the hysteretic behavior of the RC pier with a small number of parameters, in which the nonlinear behavior is described in logical forms rather than analytical expressions. Hence, the modified extended Kalman filter is employed to construct the state transition matrix using a finite difference scheme. The sequential modified extended Kalman filter algorithm is proposed to identify the unknown parameters and the state vector separately in two steps, so that the size of the problem for each identification procedure may be reduced and possible numerical problems may be avoided. Mode superposition with a modal sorting technique is also proposed to reduce the size of the identification problem for the nonlinear dynamic system with multi-degrees of freedom. Example analysis is carried out for a continuous bridge with a RC pier subjected to earthquake loads in the longitudinal and transverse directions.