• Title/Summary/Keyword: Model RC structure

Search Result 267, Processing Time 0.028 seconds

Experimental and Analytical Evaluation of the Seismic performance of a Concrete Box Structure Strengthened with Pre-flexed Members (프리플렉스 부재를 이용한 콘크리트 박스 구조물 내진보강에 관한 실험 및 해석적 평가)

  • Ann, Ho-June;Song, Sang-Geun;Min, Dae-Hong;An, Sang-Mi;Kong, Jung-Sik
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.29 no.5
    • /
    • pp.397-403
    • /
    • 2016
  • During the rapid economic growth in Korea since the 1970s, many underground facilities were constructed such as under passes and railways. Seismic design has been mandated in 1988, but the structures built before 1988 were not reflected on the seismic design. Accordingly, these underground structures require effective seismic reinforcing methods to ensure safety when the earthquake happens. By these reasons, in this study, using the proposed pre-flexed members, RC box structure was analyzed for seismic reinforcement of the corner. This method is based on a principle that enlarging the resistance against the external force by installing the pre-flexed member to the box structure corner. To evaluate validity, a newly developed member with CornerSafe was compared with traditional type reinforcement using experiments and finite element analysis. In finite element mode, nonlinearity of steel was modeled based on J2 plasticity model and concrete was based on CEB FIP MODEL CODE 1990. Also, composite ratios of box and pre-flexed member were computed for design application. The reinforcement and box structure were analyzed under the bond condition completely attached by the tie, and the results of experiment and finite element analysis were same in the force-displacement curve.

PCB Plane Model Including Frequency-Dependent Losses for Generic Circuit Simulators (범용 회로 시뮬레이터를 위한 손실을 반영한 PCB 평판 모형)

  • Baek, Jong-Humn;Jeong, Yong-Jin;Kim, Seok-Yoon
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.41 no.6
    • /
    • pp.91-98
    • /
    • 2004
  • This paper proposes a PCB plane model for generic SPICE circuit simulators. The proposed model reflects two frequency-dependent losses, namely skin and dielectric losses. After power/ground plane pair is divided into arrays of unit-cells, each unit-cell is modeled using a transmission line and two loss models. The loss model is composed of a resistor for DC loss, series HL ladder circuit for skin loss and series RC ladder circuit for dielectric loss. To verify the validity of the proposed model, it is compared with SPICE ac analysis using frequency-dependent resistors. Also, we show that the estimation results using the proposed model have a good correlation with that of VNA measurement for the typical PCB stack-up structure of general desktop PCs. With the proposed model, not only ac analysis but also transient analysis can be easily done for circuits including various non-linear/linear devices since the model consists of passive elements onl.

Real-time structural damage detection using wireless sensing and monitoring system

  • Lu, Kung-Chun;Loh, Chin-Hsiung;Yang, Yuan-Sen;Lynch, Jerome P.;Law, K.H.
    • Smart Structures and Systems
    • /
    • v.4 no.6
    • /
    • pp.759-777
    • /
    • 2008
  • A wireless sensing system is designed for application to structural monitoring and damage detection applications. Embedded in the wireless monitoring module is a two-tier prediction model, the auto-regressive (AR) and the autoregressive model with exogenous inputs (ARX), used to obtain damage sensitive features of a structure. To validate the performance of the proposed wireless monitoring and damage detection system, two near full scale single-story RC-frames, with and without brick wall system, are instrumented with the wireless monitoring system for real time damage detection during shaking table tests. White noise and seismic ground motion records are applied to the base of the structure using a shaking table. Pattern classification methods are then adopted to classify the structure as damaged or undamaged using time series coefficients as entities of a damage-sensitive feature vector. The demonstration of the damage detection methodology is shown to be capable of identifying damage using a wireless structural monitoring system. The accuracy and sensitivity of the MEMS-based wireless sensors employed are also verified through comparison to data recorded using a traditional wired monitoring system.

A Study on the GIC Circuit and Its Application (GIC 회로 및 그 응용에 관한 연구)

  • 이영근
    • Journal of the Korean Institute of Telematics and Electronics
    • /
    • v.9 no.3
    • /
    • pp.9-16
    • /
    • 1972
  • In this article it is shown that a GIC circuit with conversion "s" can be realized and a inductor is realized as a RC active two terminal network by using it instead of a gyrator. It is also shown that arbitary stable transfer functions can be realized as the open-circuit voltage ratio of 2 port networks which include GIC;s. In relizing the GIC circuit using transistors, it is made clear that the nullatornorator model of atransistor can be successfully applied at least in the frequency range below 10kHz. The synthesis method using GIC's is characterized with the followings; First, arbitrary stable transfer functions are realized systematically by repeating very simple network structure. Second, in the overall network all circuit elements except GICs are only resistors. Third, the number of condensers in the overall network necessary for realizing the transfer function of n-th order are n, which is believed to be the least number expected. expected.

  • PDF

Model verification and assessment of shear-flexure interaction in pile foundations

  • Lemnitzer, Anne;Nunez, Eduardo;Massone, Leonardo M.
    • Earthquakes and Structures
    • /
    • v.11 no.1
    • /
    • pp.141-163
    • /
    • 2016
  • Fiber models have been developed and applied to various structural elements such as shear walls, beams and columns. Only scarcely have fiber models been applied to circular foundation systems such as cast in drilled holes shafts (CIDH). In pile foundations with constraint head boundary conditions, shear deformations can easily contribute to the lateral pile response. However, soil structure interaction formulations such as the p-y method, commonly used for lateral pile design, do not include structural shear deformations in its traditional derivation method. A fiber model that couples shear and axial-bending behavior, originally developed for wall elements was modified and validated on circular cross sections (columns) before being applied to a 0.61 m diameter reinforced concrete (RC) pile with fixed head boundary conditions. The analytical response was compared to measured test results of a fixed head test pile to investigate the possible impact of pile shear deformations on the displacement, shear, and moment profiles of the pile. Results showed that shear displacements and forces are not negligible and suggest that nonlinear shear deformations for RC piles should be considered for fixed-head or similar conditions. Appropriate sensor layout is recommended to capture shear deformation when deriving p-y curves from field measurements.

Numerical Investigation for Cumulative Damage Assessment of a One-way RC Slab subjected to Consecutive Explosions (전산수치해석을 이용한 일방향 철근콘크리트 슬래브의 연속폭발 누적피해 평가기법 연구)

  • Ji, Hun;Sung, Seung-Hun;Chong, Jin Wung;Choi, Yoon Soo
    • Journal of the Korea Society for Simulation
    • /
    • v.29 no.2
    • /
    • pp.119-127
    • /
    • 2020
  • This study numerically investigated a structural behavior subjected to consecutive explosions. To this end, a small scale one-way reinforced slab (RC) with fixed-fixed boundary condition was considered as the target structure, and a commercial software, LS-DYNA, was utilized for finite element (FE) analysis. Prior to performing FE analysis, preliminary tests were carried out to verification of a computational model for the one-way RC slab. In the numerical simulation, identical blast loads were consecutively applied to the structure, and cumulative damage assessment were carried out based on its maximum dynamic displacements. As a result of the numerical simulation, it was found that maximum displacements considering permanent deformation due to a prior explosion were almost linearly increased in every explosion until the hazardous damage threshold.

Effects of Seismic Loads with Different Return Period on Residential Building with RC Shear Wall Structure under Construction (주거용 RC 벽식 건물의 시공 중 재현주기에 따른 지진하중의 영향)

  • Choi, Seong-Hyeon;Kim, Jea-Yo
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.26 no.2
    • /
    • pp.43-50
    • /
    • 2022
  • Even though the structural safety is confirmed in the design stage, the structural safety is not guaranteed in the construction stage because the structural system is not completed. In addition, since the construction period is shorter than the period of use of the building after completion, it is excessive to apply the same seismic load to the construction stage as in the design stage. ASCE 37-14 presents the concept of seismic load reduction factor during construction, but does not provide a clear application method. Therefore, in this study, the seismic load reduced according to the return period was applied to the example model of a residential middle-rise RC building. The construction stage of the example model was divided into five-story units, and seismic load with the change of the return period was applied to the construction stage models to analyze the change of seismic load during construction and to check the sectional performances of structural members. By comparing the design strength ratio of the shear wall at the design stage and the construction stage, the range of seismic load magnitudes that can assure the safety during construction of a residential middle-rise RC building was analyzed in terms of the return period.

An Analytical Study on the Elasto-Plastic Behavior of Reinforced Concrete Structure under Monotonic & Cyclic Load (단조 증가 및 반복 하중을 받는 철근 콘크리트 구조물의 탄소성 거동에 대한 해석적 연구)

  • 김화중;박정민;마은희
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 1993.10a
    • /
    • pp.131-138
    • /
    • 1993
  • To analysis machanical behavior for RC frame under monotonic & Cyclic load, it is needed to investigate elasto-plastic behavior for steel & concrete. Therefore, in this study, we idealized material model(steel and concrete) to take into account elasto-plastic, limit state, and developed structural analysis program that consider complex non-linearity. We investigated simple beam and portal frame under cyclic & monotonic loading, so we confirmed the propriety.

  • PDF

Life Expectation of Salt Attack for Fire Damaged RC Structure (화재피해를 입은 콘크리트 건축물의 염해 내구수명 산정)

  • Park, Dong-Cheon
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2017.05a
    • /
    • pp.15-16
    • /
    • 2017
  • The properties of concrete damaged by fire change according to the temperature. Diffusion coefficient of chloride ion also can change which affect the life expectation under salt circumstance. Diffusion coefficient was measured by NT BUILD 492 using the concrete specimen damaged by high temperature. FEM analysis was performed to predict the life expectancy which can help to diagnose the concrete diagnose and to design maintenance strategy.

  • PDF

Numerical Analysis of Nuclear-Power Plant Subjected to an Aircraft Impact using Parallel Processor (병렬프로세서를 이용한 원전 격납건물의 항공기 충돌해석)

  • Song, Yoo-Seob;Shin, Sang-Shup;Jung, Dong-Ho;Park, Tae-Hyo
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.24 no.6
    • /
    • pp.715-722
    • /
    • 2011
  • In this paper, the behavior of nuclear-power plant subjected to an aircraft impact is performed using the parallel analysis. In the erstwhile study of an aircraft impact to the nuclear-power plant, it has been used that the impact load is applied at the local area by using the impact load-time history function of Riera, and the target structures have been restricted to the simple RC(Reinforced Concrete) walls or RC buildings. However, in this paper, the analysis of an aircraft impact is performed by using a real aircraft model similar to the Boeing 767 and a fictitious nuclear-power plant similar to the real structure, and an aircraft model is verified by comparing the generated history of the aircraft crash against the rigid target with another history by using the Riera's function which is allowable in the impact evaluation guide, NEI07-13(2009). Also, in general, it is required too much time for the hypervelocity impact analysis due to the contact problems between two or more adjacent physical bodies and the high nonlinearity causing dynamic large deformation, so there is a limitation with a single CPU alone to deal with these problems effectively. Therefore, in this paper, Message-Passing MIMD type of parallel analysis is performed by using self-constructed Linux-Cluster system to improve the computational efficiency, and in order to evaluate the parallel performance, the four cases of analysis, i.e. plain concrete, reinforced concrete, reinforced concrete with bonded containment liner plate, steel-plate concrete structure, are performed and discussed.