• Title/Summary/Keyword: Actual load

Search Result 1,414, Processing Time 0.033 seconds

Ductility Confinement of RC Rectangular Shear Wall (장방형 철근 콘크리트 전단벽의 연성 보강)

  • 강수민;박홍근
    • Journal of the Korea Concrete Institute
    • /
    • v.14 no.4
    • /
    • pp.530-539
    • /
    • 2002
  • In designing the boundary confinement of shear walls, the current design provisions and recommendations are empirical and prescriptive; they specify a certain confinement length and details, regardless of the actual requirement of ductility Therefore, they are inappropriate to the performance based-design. The purpose of the present study is to develop a ductility design method that Is applicable to the performance based-design of shear wall. For the purpose, experimental studies were performed to investigate variations in the ductility of shear walls with the length of the boundary confinement. Five specimens modeling the compressive zone of cross sections with different confinement area were tested against eccentric vertical load. Through the experimental studies, strength, ductility, and failure mode of the compression zone were investigated. In addition, nonlinear numerical analyses for the overall cross-sections of shear wall were performed to investigate variations of the stress and strain profiles with the length of compression zone. On the basis of the experimental and numerical studies, a ductility design method for shear wall was developed. By using the proposed design method, for a given ductility demand, the area of lateral confinement and corresponding reinforcement ratio can be precisely determined so that the ductile behavior and economical design are assured.

Characteristics and Combined Sewer Overflows (합류식 하수관거의 유출 특성 분석 조사)

  • An, Ki-Sun;Jang, Sung-Ryong;Kwon, Young-Ho
    • Journal of Environmental Science International
    • /
    • v.19 no.6
    • /
    • pp.747-753
    • /
    • 2010
  • It follows in quality and sewage exclusion method of the investigation objective sector and the Combined Sewer Overflows which is suitable in regional characteristics and the confluence area against the rainfall initially a flow and the medulla and measurement - it analyzes the initial rainfall outflow possibility control plan which is suitable in the domestic actual condition and it proposes the monitor ring plan for the long-term flow and pollution load data accumulation. From the research which it sees the Infiltration water/Influent water and CSOs investigation it passes by the phase of hazard chain and Namwon right time 4 it does not hold reverse under selecting, Measurement it used the hazard automatic flow joint seal Sigma 910 machine and in case 15 minute interval of the I/I, it measured a flow at case 5, 15 minute standing of the CSOs. The water quality investigation for the water leakage investigation of the I/I and the sewage from the point which is identical with flow measurement during on-the-spot inspection duration against 6 items which include the BOD sampling and an analysis, when the rainfall analysis for CSOs fundamental investigation analyzed against 18 items which include the BOD sampling. Consequently, for the optimum interpretation invasion water / inflow water of the this investigation area day average the lowest flow - water quality assessment veterinarian optimum interpretation hazard average per day - lowest flow - it averages a medulla evaluation law department one lowest flow evaluation technique and it selects, it presentation collectively from here it gets, position result with base flow analysis of invasion water / inflow water.

Effective Parallel Hash Join Algorithm Based on Histoftam Equalization in the Presence of Data Skew (데이터 편재 하에서 히스토그램 변환기법에 기초한 효율적인 병렬 해쉬 결합 알고리즘)

  • Park, Ung-Gyu;Choe, Hwang-Gyu;Kim, Tak-Gon
    • The Transactions of the Korea Information Processing Society
    • /
    • v.4 no.2
    • /
    • pp.338-348
    • /
    • 1997
  • In this pater, we first propose a data distribution framework to resolve load imbalance and bucket oerflow in parallel hash join.Using the histogram equalization technique, the framework transforms a histogram of skewed data to the desired uniform distribution that corresponds to the relative computing power of node processors in the system.Next we propose an effcient parallel hash join algorithm for handing skwed data based on the proposed data distribution methodology.For performance comparison of our algorithm with other hash join algorithms.we perform similation experiments and actual exeution on COREDB database computer with 8-node hyperube architecture. In these experiments, skwed data distebution of the join atteibute is modeled using a Zipf-like distribution.The perfomance studies undicate that our algorithm outperforms other algorithms in the skewed cases.

  • PDF

Verification Experiment of a Water-to-air Ground Source Multi-heat Pump System (물-공기 지열 멀티형 열펌프 시스템 실증연구)

  • Kim, Cheol-Woo;Kim, Byoung-Kook;Lee, Pyeong-Gang;Lim, Hyo-Jae;Kang, Shin-Hyung;Choi, Jong-Min
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
    • /
    • v.6 no.1
    • /
    • pp.9-16
    • /
    • 2010
  • The aim of this study is to verify the performance of water-to-air multi-heat pump system with a vertical U-tube GLHX(U-tube system) and a double tube GLHX(double tube system), which were installed in a school building located in Asan. For analyzing the performance of the GSHP system, we monitored various operating da~ including the water temperature of inlet and outlet of the ground heat exchanger, mass flow rate, and power consumption. Daily average COP of the single U-tube system and the double tube system were 4.5 and 4.2 at cooling mode and were 3.5 and 3.8 at heating mode. As a result, We know that performance of water-to-air multi-heat pump unit is reliable at actual condition operated in a part load conditions for all day.

Finite element model updating of long-span cable-stayed bridge by Kriging surrogate model

  • Zhang, Jing;Au, Francis T.K.;Yang, Dong
    • Structural Engineering and Mechanics
    • /
    • v.74 no.2
    • /
    • pp.157-173
    • /
    • 2020
  • In the finite element modelling of long-span cable-stayed bridges, there are a lot of uncertainties brought about by the complex structural configuration, material behaviour, boundary conditions, structural connections, etc. In order to reduce the discrepancies between the theoretical finite element model and the actual static and dynamic behaviour, updating is indispensable after establishment of the finite element model to provide a reliable baseline version for further analysis. Traditional sensitivity-based updating methods cannot support updating based on static and dynamic measurement data at the same time. The finite element model is required in every optimization iteration which limits the efficiency greatly. A convenient but accurate Kriging surrogate model for updating of the finite element model of cable-stayed bridge is proposed. First, a simple cable-stayed bridge is used to verify the method and the updating results of Kriging model are compared with those using the response surface model. Results show that Kriging model has higher accuracy than the response surface model. Then the method is utilized to update the model of a long-span cable-stayed bridge in Hong Kong. The natural frequencies are extracted using various methods from the ambient data collected by the Wind and Structural Health Monitoring System installed on the bridge. The maximum deflection records at two specific locations in the load test form the updating objective function. Finally, the fatigue lives of the structure at two cross sections are calculated with the finite element models before and after updating considering the mean stress effect. Results are compared with those calculated from the strain gauge data for verification.

CWT-Based Method for Identifying the Location of the Impact Source in Buried Pipes (연속웨이브렛 변환을 이용한 충격음 위치 규명)

  • Kim, Eui-Youl;Kim, Min-Su;Lee, Sang-Kwon;Koh, Jae-Pil
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.34 no.11
    • /
    • pp.1555-1565
    • /
    • 2010
  • This paper presents a new method for indentifying the location of impact source in a buried duct. In a gas pipeline, the problem of leakage occurs due to the mechanical load exerted by construction equipment. Such leakage can cause catastrophic disasters in gas supply industries. Generally, the cross-correlation method has been used for indentifying the location of impact source in a pipeline. Since this method involves the use of the dispersive acoustic wave, it derives an amount of error in process of estimating the time delay between acoustic sensors. The object of this paper is to estimate the time delay in the arrival of the direct wave by using the wavelet transform instead of the dispersive wave. The wavelet transform based method gives more accurate estimates of the impact location than the cross-correlation method does. This method is successfully used to identify the location of impact force in an actual buried gas duct.

Current Status and Problems of Communication between Teachers and Parents using SMS (SMS를 활용한 교사와 학부모의 의사소통 실태 및 과제)

  • Cha, Kyoung-Soo;Jo, Mi-Heon
    • Journal of The Korean Association of Information Education
    • /
    • v.13 no.1
    • /
    • pp.60-68
    • /
    • 2009
  • With the increase of double-income families, parents are not free in terms of time and space in communicating with teachers. Also for teachers, with many students and heavy load of work, communication with parents has been poor. As a means for overcoming this kind of situation, this research examined the current status of communication between teachers and parents using SMS and problems to solve. The investigation of the actual conditions of SMS use showed that there was a high number of answers pointing out that SMS is needed for the exchange of information regarding children and educational activities, and teachers pointed out that the communication was effective for exchanging educational information regarding children whereas parents pointed out that it was effective in improving the children's attitudes. Based on the results of the analysis, the following was found as tasks to be solved: preparing a plan for revitalizing SMS use, solving the burden that parents have in communicating with teachers, becoming more friendly with teachers, investigation of the reason why there is no response regarding SMS and preparing countermeasures, providing information appropriate to what parents want, increasing the reply rate of parents, expansion of text capacity, and trouble with getting online with a computer.

  • PDF

Standardization of composite connections for trapezoid web profiled steel sections

  • Saggaff, A.;Tahir, M.M.;Sulaiman, A.;Ngian, S.P.;Mirza, J.
    • Structural Engineering and Mechanics
    • /
    • v.55 no.4
    • /
    • pp.765-784
    • /
    • 2015
  • Connections are usually designed either as pinned usually associated with simple construction or rigid normally is associated with continuous construction. However, the actual behaviour falls in between these two extreme cases. The use of partial strength or semi-rigid connections has been encouraged by Euro-code 3 and studies on semi-continuous construction have shown substantial savings in steel weight of the overall construction. Composite connections are proposed in this paper as partial or full strength connections. Standardized connection tables are developed based on checking on all possible failure modes as suggested by "component method" for beam-to-column composite connection on major axis. Four experimental tests were carried out to validate the proposed standardised connection table. The test results showed good agreement between experimental and theoretical values with the ratio in the range between 1.06 to 1.50. All tested specimens of the composite connections showed ductile type of failure with the formation of cracks occurred on concrete slab at maximum load. No failure occurred on the Trapezoidal Web Profiled Steel Section as beam and on the British Section as column.

Evaluation of Design Fire Curves for Single Combustibles in a Cinema Complex (복합영상관 단일 가연물의 디자인 화재곡선 평가)

  • Jang, Hyo-Yeon;Hwang, Cheol-Hong;Oh, Chang Bo;Nam, Dong-Gun
    • Fire Science and Engineering
    • /
    • v.34 no.3
    • /
    • pp.18-27
    • /
    • 2020
  • An actual fire test was performed on single combustibles placed in a local cinema complex, and quantitative differences in the maximum heat release rate (HRR) and fire growth rate were investigated based on the design fire curve methods (i.e., the general and 2-stage methods). In terms of combustible use and fire load, a total of 12 combustibles were selected, classified into cinema lounge and movie theater. It was found that the maximum HRR and fire growth rate determined using the two-stage method were quantitatively different from those of the general method. The application of the two-stage method, which can be used to determine the fire growth rate of the initial fire stage more precisely, could be useful in accurately predicting the activation time of fire detectors and fire-extinguishing facilities, as well as the available safe egress time (ASET) and required safe egress time (RSET).

平面應力 破壞靭性値 擧動에 관한 硏究

  • 송삼홍;고성위;정규동
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.11 no.3
    • /
    • pp.376-385
    • /
    • 1987
  • In this study, the plane stress fracture toughness and Tearing modulus are investigated for various crack ratios using the J integral. To evaluate the J integral and Tearing modulus, both experiments and estimation are used. The thickness of the low carbon steel specimens that is used in the experiments is 3mm. The type of specimen that is considered in the study is center-cracked-tension one. The measurements of crack length are performed by unloading compliance method. In the estimation of crack parameters such as the J integral and load line displacement, the Ramberg and Osgood stress strain law is assumed. Then simple formulas are given for estimating the crack parameters from contained yielding to fully plastic solutions. Obtained results are as follows; (1) When the crack ratio is in the range of 0.500 - 0.701, the plane stress fracture toughness is almost constant regardless of crack ratios. (2) The fracture toughness (J_c/) and Tearing modulus (T) obtained are J_c/=28.51kgf/mm, T=677.7 for base metal, J_c/=31.85kgf/mm, T=742.0 for annealed metal. (3) Simpson's and McCabe's formulas which consider crack growth in estimating J integral are shown more conservative J and lower T than Rice's and Sumpter's. (4) Comparison of the prediction with the actual experimental measurements by Simpson's formula shows good agreement.