• Title, Summary, Keyword: pseudo-dynamic test

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Seismic Performance Evaluation of Seismic Strengthening Method using SRCF External Connection of Medium and Low-rise R/C Buildings (중·저층 철근콘크리트 건물의 SRCF 외부접합 내진보강공법의 내진성능 평가)

  • Lee, Kang-Seok;Jung, Jue-Seong;Lee, Jong-Kweon
    • Journal of the Korea Concrete Institute
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    • v.27 no.2
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    • pp.147-155
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    • 2015
  • A new SRCF (Steel Reinforced Concrete Frame) external connection method for seismic strengthening of medium-and low-rise reinforced concrete buildings is reported in this paper. The SRCF method, proposed in this study, is capable of carrying out the seismic retrofitting construction while residents can live inside building. The method is one of the strength design approach by retrofit which can easily increase the ultimate lateral load capacity of concrete buildings controlled by shear. The pseudo-dynamic test, designed using a existing school building in Korea, was carried out in order to verify the seismic strengthening effects of the proposed method in terms of the maximum load carrying capacity and deformation. Test results revealed that the proposed SRCF strengthening method installed in RC frame enhanced conspicuously the strength and deformation capacities, and the method can resist markedly under the large scaled earthquake intensity level.

System Identification of Dynamic Systems Using Structural Reanalysis Method (재해석 기법을 이용한 동적 구조시스템의 System Identification)

  • Han, Kyoung-Bong;Park, Sun-Kyu;Kim, Hyeong-Yeol
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.421-424
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    • 2004
  • Model updating is a very active research field, in which significant efforts has been invested in recent years. Model updating methodologies are invariably successful when used on noise-free simulated data, but tend to be unpredictable when presented with real experimental data that are-unavoidably-corrupted with uncorrelated noise content. In this paper, Reanalysis using frequency response functions for correlating and updating dynamic systems is presented. A transformation matrix is obtained from the relationship between the complex and the normal frequency response functions of a structure. The transformation matrix is employed to calculate the modified damping matrix of the system. The modified mass and stiffness matrices are identified from the normal frequency response functions by using the least squares method. Full scale pseudo dynamic pier test is employed to illustrate the applicability of the proposed method. The result indicate that the damping matrix of correlated finite element model can be identified accurately by the proposed method. In addition, the robustness of the new approach uniformly distributed measurement noise is also addressed.

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Evaluation of the Application and Analysis Method at Seismic Design of Dam (댐의 내진설계시 해석방법과 그 적용성 평가)

  • Hwang, Seong-Chun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.9
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    • pp.4239-4249
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    • 2011
  • In the country with frequent earthquakes like Japan, resistance to earthquake is assessed on the basis that Dam body's Face slab is destroyed by concentrated stress. In our country this kind of modeling and analysis is not yet definitely established. This paper performed pseudo static analysis and dynamic analysis for CFRD and evaluated reliability with the results of Shaking Table Test. The Seismic coefficient method, modified seismic coefficient method, Newmark method of Pseudo-static analysis and frequency domain response analysis, time domain history analysis of dinamic analysis were used. The analysis results were differ between analysis method, but the trends of acceleration and displacement were good agreement with the results of shaking table test.

Evaluation Test for the Bridges Retrofitted Seismically with LRB (LRB로 내진보강된 교량의 성능검증 실험)

  • Kwahk, Im-Jong;Cho, Chang-Beck;Kim, Young-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.109-112
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    • 2006
  • In this study, an approach that installs seismic isolation bearings was proposed for the seismic retrofit of the existing bridges. The method that replaces all existing bearings with seismic isolators was proposed already. However, in this study, we recommend to utilize the existing bearings for the benefit of safety and cost. According to our proposal, the seismic isolators do not support vertical loads but they just function as the period shifter and the horizontal damper. To verify this approach experimentally, the real scale bearings and isolators for the real highway bridges were designed and fabricated. And the responses of this isolated bridges to the assumed earthquakes were determined by the pseudo dynamic test scheme. The test results were also compared to the responses computed by the well known structural analysis software to check the reliability of the test. From the test results, we found that the retrofitted bridges using the proposed method showed stable performances under earthquakes.

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Dynamic Testing for Word - Oriented Memories (워드지향 메모리에 대한 동적 테스팅)

  • Young Sung H.
    • Journal of the Korea Computer Industry Society
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    • v.6 no.2
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    • pp.295-304
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    • 2005
  • This paper presents the problem of exhaustive test generation for detection of coupling faults between cells in word-oriented memories. According to this fault model, contents of any w-bit memory word in a memory with n words, or ability tochange this contents, is influenced by the contents of any other s-1 words in the memory. A near optimal iterative method for construction of test patterns is proposed The systematic structure of the proposed test results in simple BIST implementations.

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Design of High-Reliability eFuse OTP Memory for PMICs (PMIC용 고신뢰성 eFuse OTP 메모리 설계)

  • Yang, Huiling;Choi, In-Wha;Jang, Ji-Hye;Jin, Liyan;Ha, Pan-Bong;Kim, Young-Hee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.7
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    • pp.1455-1462
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    • 2012
  • In this paper, a BCD process based high-reliability 24-bit dual-port eFuse OTP Memory for PMICs is designed. We propose a comparison circuit at program-verify-read mode to test that the program datum is correct by using a dynamic pseudo NMOS logic circuit. The comparison result of the program datum with its read datum is outputted to PFb (pass fail bar) pin. Thus, the normal operation of the designed OTP memory can be verified easily by checking the PFb pin. Also we propose a sensing margin test circuit with a variable pull-up load out of consideration for resistance variations of programmed eFuse at program-verify-read mode. We design a 24-bit eFuse OTP memory which uses Magnachip's $0.35{\mu}m$ BCD process, and the layout size is $289.9{\mu}m{\times}163.65{\mu}m$ ($=0.0475mm^2$).

Ductility Assesment of Damaged RC Bridge Piers w with Lap-Spliced Bars

  • Chung, Young-Soo;Park, Chang-Kyu;Lee, Eun-Hee
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.453-456
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    • 2003
  • This research is to evaluate the seismic performance of reinforced concrete bridge piers with lap-spliced longitudinal reinforcement steels in the plastic hinge region, and to develop the enhancement scheme of their seismic capacity. Six circular columns of 0.6m diameter and 1.5m height were made with two confinement steel ratios. They were damaged under series of artificial earthquakes that could be compatible in Korean peninsula. Directly after the pseudo-dynamic test, damaged columns were retested under inelastic reversal cyclic loading simultaneously under an axial load, P=$0.1f_{ck}A_{g}$, and residual seismic performance of damaged columns was evaluated. Test results show that RC bridge piers with lap-spliced longitudinal steels behaved with minor damage even under artificial earthquakes with 0.22g PGA, but failed at low ductility subjected to the subsequent quasi-static load test. This failure was due to the debonding of the lap splice. The specimens externally wrapped with composite FRP straps in the potential plastic hinge region showed significant improvement both in flexural strength and displacement ductility.

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Computational enhancement to the augmented lagrange multiplier method for the constrained nonlinear optimization problems (구속조건식이 있는 비선형 최적화 문제를 위한 ALM방법의 성능향상)

  • 김민수;김한성;최동훈
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.2
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    • pp.544-556
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    • 1991
  • The optimization of many engineering design problems requires a nonlinear programming algorithm that is robust and efficient. A general-purpose nonlinear optimization program IDOL (Interactive Design Optimization Library) is developed based on the Augmented Lagrange Mulitiplier (ALM) method. The ideas of selecting a good initial design point, using resonable initial values for Lagrange multipliers, constraints scaling, descent vector restarting, and dynamic stopping criterion are employed for computational enhancement to the ALM method. A descent vector is determined by using the Broydon-Fletcher-Goldfarb-Shanno (BFGS) method. For line search, the Incremental-Search method is first used to find bounds on the solution, then the bounds are reduced by the Golden Section method, and finally a cubic polynomial approximation technique is applied to locate the next design point. Seven typical test problems are solved to show IDOL efficient and robust.

The Evaluation of Seismic Performance for Concrete-filled Steel Piers (콘크리트 충전 강교각의 내진 성능 평가)

  • 정지만;장승필;인성빈
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.5
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    • pp.53-58
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    • 2002
  • A recent development, a concrete-filled steel(CFS) pier is an alternative to a reinforced concrete bridge pier in an urban area, because of its fast construction and excellent ductility against earthquakes. The capacity of CFS piers has not been used to a practical design, because there is no guide of a seismic design for CFS piers. Therefore, the guide of a seismic design value is derived from tests of CFS piers in order to apply it to a practical seismic design. Steel piers and concrete-filled steel piers are tested with constant axial load using quasi-static cyclic lateral load to check ductile capacity and using the real Kobe ground motion of pseudo-dynamic test to verify seismic performance. The results prove that CFS piers have more satisfactory ductility and strength than steel piers and relatively large hysteretic damping in dynamic behaviors. The seismic performance of steel and CFS piers is quantified on the basis of the test results. These results are evaluated through comparison of both the response modification factor method by elastic response spectrum and the performance-based design method by capacity spectrum and demand spectrum using effective viscous damping. The response modification factor of CFS piers is presented to apply in seismic design on a basis of this evaluation for a seismic performance.

The Seismic Performance for Concrete-filled Steel Piers (콘크리트 충전 강교각의 내진 성능)

  • 정지만;장승필;인성빈
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.189-196
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    • 2002
  • The capacity of CFS piers has not been used to a practical design, because there is no guide of a seismic design for CFS piers. Therefore, the guide of a seismic design value is derived from tests of CFS piers in order to apply it to a practical seismic design. Steel piers and concrete-filled steel piers are tested with constant axial load using quasi-static cyclic lateral load to check ductile capacity and using the real Kobe ground motion of pseudo-dynamic test to verify seismic performance. The results prove that CFS piers have more satisfactory ductility and strength than steel piers and relatively large hysteretic damping in dynamic behaviors. The seismic performance of steel and CFS piers is quantified on the basis of the test results. These results are evaluated through comparison of both the response modification factor method by elastic response spectrum and the performance-based design method by capacity spectrum and demand spectrum using effective viscous damping. The response modification factor of CFS piers is presented to apply in seismic design on a basis of this evaluation for a seismic performance.

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