• Title/Summary/Keyword: RC교각

Search Result 210, Processing Time 0.027 seconds

Strain Analysis of Longitudinal Reinforcing Steels of RC Bridge Piers Under Shaking Test (진동대 실험에 의한 RC교각의 주철근 변형률 분석)

  • Hong, Hyun-Ki;Yang, Dong-Wook;Chung, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2008.11a
    • /
    • pp.93-96
    • /
    • 2008
  • The near fault ground motion(NFGM) is characterized by a single long period velocity pulse of large magnitude. NFGM's have been observed in recent strong earthquakes, Turkey Izmit (1999), Japan Kobe(1995), Northridge(1994), etc. These strong earthquakes have caused considerable damage to infrastructures because the epicenter was close to the urban area, called as NFGM. Extensive research for the far fault ground motion(FFGM) have been carried out in strong seismic region, but limited research have been done for NFGM in low or moderate seismic regions because of very few records. The purpose of this study is to investigate and analyze the effect of near-fault ground motions on RC bridge piers without lap-spliced longitudinal reinforcing steels. The seismic performance of two RC bridge piers under near-fault ground motions was investigated on the shake table. In addition, Two of four identical RC bridge piers were tested under a quasi-static load, and the others were under a pseudo-dynamic load. The respectively two RC bridge pier is comparatively subjected to Pseudo-dynamic loadings and Quasi-Static loadings. This paper indicated that more gives bigger ultimate strain of longitudinal steels to be fractured at bigger PGA motion.

  • PDF

Seismic Evaluation of the Existing RC Piers (기존 철근콘크리트 교각의 내진성평가)

  • 전귀현;이지훈
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.2 no.4
    • /
    • pp.155-168
    • /
    • 1998
  • In this paper, the structural properties of the existing reinforced concrete(RC) piers are surveyed and the major factors influencing the member strength and deformation capacity are identified. Also a seismic evaluation procedure of RC piers is presented. The factors controlling the member strength are the applied axial load, the reinforcement ratio and yield strength of longitudinal rebar for flexural strength, and the transverse reinforcement for shear strength. Member deformation capacity largely depends on transverse reinforcement ratio and anchor detail, and splice location of longitudinal reinforcement. The above structural detail should be investigated for the detail seismic evaluation of RC piers. The most of existing RC piers have inadequate transverse reinforcement anchor details and the splices of longitudinal reinforcement in the pier bottom where plastic hinges are formed after yielding. Therefore the deformation capacity is not enough for the ductile flexural behavior of the RC piers. The presented evaluation procedure can be used for the rational decisions as to seismic retrofitting of the existing RC piers.

  • PDF

Experimental Behavior of Reinforced Concrete Column-Bent Piers under Bidirectional Repeated Loading (이축반복하중을 받는 2주형 철근콘크리트 교각의 실험거동)

  • Park, Chang-Kyu;Lee, Beom-Gi;Song, Hee-Won;Chung, Young-Soo
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.9 no.1 s.41
    • /
    • pp.17-24
    • /
    • 2005
  • Response of reinforced concrete (RC) column-bent piers subjected to bidirectional seismic loadings was experimentally investigated. RC column-bent piers represent one of the most popular shapes of piers used in Korea highway bridges. Four column-bent piers were constructed in 400 mm diameter and 2,000 mm height. Each pier has two circular supporting columns. These piers were tested under bidirectional lateral load reversals with an axial load of $0.1f_{ck}A_g$. The test parameters included : different transverse reinforcement contents and lap-spliced longitudinal reinforcing steels. Test results indicate that the lap splice of longitudinal reinforcing steels have significantly influenced on hysteretic response of column-bent piers similar to previous test results for single columns with corresponding test parameters. Column capacity was changed with the level of transverse confinement. From the comparison of test result for single column under unidirectional loading, the damage of single column was concentrated on lower plastic hinge region but the damage of column-bent piers was scattered to upper and lower plastic hinge region.

Limited-Ductile Seismic Design and Performance Assessment Method of RC Bridge Piers Based on Displacement Ductility (변위연성도 기반 철근콘크리트 교각의 한정연성 내진 설계법과 성능평가 방법)

  • Park, Chang-Kyu;Chung, Young-Soo;Lee, Dae-Hyoung
    • Journal of the Korea Concrete Institute
    • /
    • v.19 no.1
    • /
    • pp.19-26
    • /
    • 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.

Quasi-Static Tests for Seismic Performance of Circular RC Bridge Piers (단일주 원형 철근콘크리트 교각의 내진거동에 관한 준정적 실험)

  • 정영수;이강균;한기훈;박종협
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.3 no.2
    • /
    • pp.55-66
    • /
    • 1999
  • Eight RC bridge plers have been made on a 1/3.4 scale model and have been tested in a quasi-static cyclic load so as to investigate their seismic performance. The ultimate objective of this experimental study is to investigate the hysteretic behavior of reinforced concrete plers, which have been widely used for urban transportation facilities in Korea. Improtant test parameters are hoop ratio, axial load, load pattern, and etc. And noninear behaviors of test columns have been evaluated through their yield and ultimate strength, energy dissipation, ductility and load-deflection characteristics under quasi-static cyclic loads. From the quasi-static tests on 8 bridge piers, it is concluded that energy dissipation, ultimate strength and curvature for a given displacement factor ${\mu}={\Delta}/{\Delta}_y$ are higher for the seismically designed columns than for the nonseismically designed columns.

  • PDF

Shake Table Response and Analysis of RC Bridge Piers with Lap-Spliced Steel under NFGM (주철근 겹침이음된 RC교각의 근단층지반운동에 대한 진동대 응답과 분석)

  • Chung, Young-Soo;Park, Chang-Young;Hong, Hyun-Ki;Park, Ji-Ho;Shim, Chang-Su
    • Journal of the Korea Concrete Institute
    • /
    • v.20 no.4
    • /
    • pp.451-458
    • /
    • 2008
  • The near-fault ground motion (NFGM) is characterized by a single long period velocity pulse of large magnitude. NFGM's have been observed in recent strong earthquakes, Izmit Turkey (1999), Kobe Japan (1995), Northridge USA (1994), etc. These strong earthquakes have caused considerable damage to infrastructures because the epicenter was close to the urban area, called as NFGM. Extensive research for the near-fault ground motion (NFGM) have been carried out in strong seismic region, but limited research have been done for NFGM in low or moderate seismic regions because of very few records. The purpose of this study is to investigate and analyze the effect of near-fault ground motions on reinforced concrete (RC) bridge piers with lap-spliced longitudinal reinforcing steels. The seismic performance of four RC bridge piers under near-fault ground motions was investigated on the shake table. In addition, a RC bridge pier is subjected to pseudo-dynamic loadings. Test results showed that large residual displacements were observed in RC bridge piers under NFGM. RC specimens on the shake table failed at relatively low displacement ductility, compared with the displacement ductility of RC bridge pier subjected to pseudo-dynamic loadings.

Seismic Retrofit of RC Columns with Lap-Spliced Longitudinal Rebars Wrapping by SMA Wires (SMA Wire를 이용한 주철근 겹침이음된 RC 교각의 내진 보강 연구)

  • Park, Yong-Kwon;Lee, Yeon-Hun;Yang, Dong-Wook;Lim, Hyeon-Sik;Chung, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2010.05a
    • /
    • pp.129-130
    • /
    • 2010
  • Lap splice of longitudinal reinforcing steels was located in the plastic hinge region of most bridge piers that had been designed and constructed before the adoption of the 1992 seismic design provision of Korea Highway Design Specification. This research aims at improving the seismic performance of reinforced concrete bridge piers with lap-spliced longitudinal steels, of which the plastic hinge region was wrapped by the shape memory alloy (SMA) wires. Quasi-static test was used to investigate the seismic behaviours of RC test specimens.

  • PDF

An Experimental Study on the Seismic Behavior of Solid RC Piers Using High Strength Concrete and High Strength Rebars (고강도 콘크리트 및 고강도 철근을 사용한 중실교각의 내진거동에 관한 실험적 연구)

  • Oh Byung-Hwan;Cho Keun-Ho;Park Dae-Kyun
    • Journal of the Korea Concrete Institute
    • /
    • v.17 no.1 s.85
    • /
    • pp.27-34
    • /
    • 2005
  • The purpose of this study is to investigate the structural behavior of RC Piers using high strength concrete and high strength rebars. The high strength concrete offers many advantages such as enhanced mechanical performance and durability, in addition to member size reduction. The high strength rebars are used here to reduce the amount of rebars, which facilitates the placement of concrete and labor works. Five RC piers were tested under a constant axial load and a cyclically reversed horizontal load. The seismic design of piers were implemented, according to the current Korean Bridge Design Code. The test variables include concrete compressive strength, steel strength, and steel ratio. The test results indicate that RC piers using the high strength concrete and high strength rebars exhibit ductile behavior and appropriate seismic performance, in compliance with the design code. The present study allows more realistic application of high strength rebars and concrete to RC piers, which will provide enhanced durability as well as more economy.

Seismic Performance Assessment of Precast Reinforced Concrete Piers with Confinement Steel (프리케스트 RC 교각의 횡방향 철근에 따른 내진성능평가)

  • Shin, Sung-Jin;Kim, Dong-Hyun;Lee, Jae-Hoon;Sim, Jae-Beum;Shin, Hyun-Yang;Park, Dong-Kyu
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2009.05a
    • /
    • pp.457-458
    • /
    • 2009
  • Totally, 12 precast RC piers were constructed and tested to evaluate the seismic performance. Experimental variables of the specimens were confinement steel amount, longitudinal steel ratio, aspect ratio, segment connecting method. Only deformed bars were used for longitudinal steel to maximize economical efficiency.

  • PDF

A Study on Seismic Behavior of Space Frame Bridge Using Three-Dimensional Nonlinear Dynamic Analysis (3차원 비선형 동적해석을 이용한 입체라멘교의 지진거동특성에 관한 연구)

  • 김익현
    • Journal of the Earthquake Engineering Society of Korea
    • /
    • v.6 no.5
    • /
    • pp.45-51
    • /
    • 2002
  • The characteristics of nonlinear seismic behavior and failure mechanism of RC space frame in railroad viaducts have been studied by the numerical analysis in time domain. The structure concerned is modeled in 3 dimensional extent and the RC frame elements consisting of fibers are employed for the columns. The fibers are characterized as RC zone and PC one to distinguish the different energy release after cracking resulted from the bond characteristic between concrete and re-bar. Due to the deviation of the mass center and the stiffness center of the entire structure the complex behavior is shown under seismic actions. The excessive shear force is concentrated on the column beside flexible one relatively, which leads to the failure of bridge concerned.