• Title/Summary/Keyword: Load Distributions

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Seismic Performance Evaluation of Multi-Span Bridges considering Effect of Lateral Load Distributions and Equivalent SDOF methods (횡하중 분포와 등가단자유도 방법의 영향을 고려한 다경간 교량의 내진성능 평가)

  • Song, Jong-Keol;Nam, Wang-Hyun;Chung, Yeong-Hwa
    • Journal of Industrial Technology
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    • v.26 no.A
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    • pp.163-171
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    • 2006
  • To evaluate inelastic seismic responses of multi-span-bridge, the equivalent single-degree-of-freedom (ESDOF) methods and the lateral load distributions are applied to the capacity spectrum method(CSM). From the pushover analysis results using the four ESDOF methods and the six types lateral load distributions, the ESDOF method more than lateral load distribution is found to have an important influence upon the pushover analysis. The effects of the higher mode on the bridge seismic behaviors are also increased as the number of pier increase. Therefore, it can be concluded that lateral load distributions and ESDOF methods for reflection of higher mode effects should be considered in the seismic analysis of the bridge structural.

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A Study on Perimeter Load Transfer Fuctions of the Large Diameter Drilled Shafts Depending on Soil Types During the Static Pile Load Tests (정재하시험시 지반종류별 대구경 현장타설말뚝의 주면하중전이함수에 관한 연구)

  • Jung, Ho-Young;Hwang, Seong Chun;Choi, Yongkyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.5C
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    • pp.163-170
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    • 2011
  • Perimeter load transfer functions were developed by an analysis of the static pile load test results of the 7 large diameter drilled shafts constructed in domestic areas. Using the pile axial load distributions obtained from the static pile load tests of large diameter drilled shafts, the unit skin frictions were analyzed and, based on unit skin friction test data, perimeter load transfer functions could be suggested. The load transfer distributions calculated by suggested functions and the load transfer functions obtained from the bi-directional pile load tests were compared. As a result, the 2 load transfer distributions were coincided, respectively.

Probabilistic Analysis of Flaw Distribution on Structure Under Cyclic Load (피로하중을 받는 구조물의 결함분포에 대한 확률론적 해석)

  • Kwak, Sang-Log;Choi, Young-Hwan;Kim, Hho-Jung
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.604-609
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    • 2003
  • Flaw geometries, applied stress, and material properties are major input variables for the fracture mechanics analysis. Probabilistic approach can be applied for the consideration of uncertainties within these input variables. But probabilistic analysis requires many assumptions due to the lack of initial flaw distributions data. In this study correlations are examined between initial flaw distributions and in-service flaw distributions on structures under cyclic load. For the analysis, LEFM theories and Monte Carlo simulation are applied. Result shows that in-service flaw distributions are determined by initial flaw distributions rather than fatigue crack growth rate. So initial flaw distribution can be derived from in-service flaw distributions.

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A study on the equivalent static wind load estimation of large span roofs (대스팬 지붕구조물의 등가정적 풍하중 산정에 관한 연구)

  • Kim, Dae-Young;Kim, Ji-Young;Kim, Han-Young;Lee, Myung-Ho;Kim, Sang-Dae
    • 한국공간정보시스템학회:학술대회논문집
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    • 2004.05a
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    • pp.245-251
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    • 2004
  • This paper discuss the conditionally sampled actual wind pressure distributions causing peak quasi-static wind loads in the large span roofs using the wind pressures at many locations on dome models measured simultaneously in a wind tunnel. The actual extreme pressure distributions are compared itk load-response-correlation (LRC) method and the quasi-steady pressure distributions. Based on the results, the reason for the discrepancy in the LRC pressure distribution and the actual extreme pressure distribution are discussed. Futhermore, a brief discussion is made of the equivalent static wind load estimation for the large span roofs.

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An Experimental Study on the Cylinder Wall Temperature Characteristics for Load Variations in a Gasoline Engine (가솔린엔진의 부하(負荷)에 따른 실린더 벽면 온도특성(溫度特性)에 관(關)한 연구(硏究))

  • Kwon, K.R.;Ko, J.K.;Hong, S.C.
    • Journal of Power System Engineering
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    • v.3 no.1
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    • pp.16-22
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    • 1999
  • The purpose of this study is to prevent the stick, scuffing, scratch between piston and cylinder, is to contribute the piston design such as piston profile, clearance by calculating reaction force by over-lap of piston skirt, as measuring the temperature distributions of cylinder wall. The experiment has been peformed to obtain data during actual engine operation. Temperature gradient in peripheral and axial distributions of cylinder wall according to torque and speed of engine were measured by use of an 800cc class gasoline engine. The results obtained are summarized as follows ; 1) The temperature of cylinder wall at TDC was about $50{\sim}75^{\circ}C$ higher than temperature of cooling water. 2) The rear side temperature of top dead center was $141^{\circ}C$(1/4 load) in axial distribution, whereas the rear side of midway position temperature was $98^{\circ}C$. 3) The temperature of cylinder wall increased in according to rising temperature of cooling water. 4) The thrust side temperature of cylinder wall was about $15^{\circ}C$ in all load test. 5) The rear side temperature of top dead center was $159^{\circ}C$ (1/2 load) in peripheral distribution, it was about $39^{\circ}C$ higher than thrust side temperature.

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Development of Load Factors Based on Optimum Reliability Analysis Model (하중 계수에 기초한 최적신뢰성해석 모델 개발)

  • 이증빈;신형우
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1992.04a
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    • pp.134-139
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    • 1992
  • This study introduces simple derivation of optimum load factors based on both cornell's MFOSM (Mean First Order End Moment) methods and Lind - Hasofers AFOSM (Advanced First Order 2nd Moment) methods and demonstrates the relationship between the optimum reliability, the load factors, the probability distributions selected to model the load, and a measure of relative failure cost. Although some of the cost parameters cannot be evaluated accurately and the upper tail characteristics of the distributions of the random loads remain uncertainty, this optimum reliability formulation provides insight on which Parameters are most significant in selecting appropriate load criteria for structure design.

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Wind load combinations and extreme pressure distributions on low-rise buildings

  • Tamura, Yukio;Kikuchi, Hirotoshi;Hibi, Kazuki
    • Wind and Structures
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    • v.3 no.4
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    • pp.279-289
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    • 2000
  • The main purpose of this paper is to demonstrate the necessity of considering wind load combinations even for low-rise buildings. It first discusses the overall quasi-static wind load effects and their combinations to be considered in structural design of low-rise buildings. It was found that the maximum torsional moment closely correlates with the maximum along-wind base shear. It was also found that the instantaneous pressure distribution causing the maximum along-wind base shear was quite similar to that causing the maximum torsional moment, and that this asymmetric pressure pattern simultaneously accompanies considerable across-wind and torsional components. Secondly, the actual wind pressure distributions causing maximum quasi-static internal forces in the structural frames are conditionally sampled and their typical pressure patterns are presented.

Load Carrying Capacity due to Cracking Damage of Ellipsoidal Inhomogeneity in Infinite Body under Pure Shear and Its Elastic Stress Distributions (전단응력하의 무한체내 타원체불균질물의 균열손상에 따른 하중부하능력과 탄성응력분포)

  • 조영태;임광희;고재용;김홍건
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.10a
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    • pp.87-90
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    • 2001
  • In particle or short-fiber reinforced composites, cracking of the reinforcements is a significant damage mode because the broken reinforcements lose load carrying capacity. This paper deals with elastic stress distributions and load carrying capacity of intact and cracked ellipsoidal inhomogeneities. Three dimensional finite element analysis has been carried out on intact and broken ellipsoidal inhomogeneities in an infinite body under pure shear. For the intact inhomogeneity, as well known as Eshelby(1957) solution, the stress distribution is uniform in the inhomogeneity and non-uniform in the surrounding matrix. On the other hand, for the broken inhomogeneity, the stress in the region near crack surface is considerably released and the stress distribution becomes more complex. The average stress in the inhomogeneity represents its load carrying capacity, and the difference of average stresses between the intact and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The load carrying capacity of the broken inhomogeneity is expressed in terms of the average stress of the intact inhomogeneity and some coefficients. It is found that the broken inhomogeneity with higher aspect ratio still maintains higher load carrying capacity.

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Homogenized limit analysis of masonry structures with random input properties: polynomial Response Surface approximation and Monte Carlo simulations

  • Milani, G.;Benasciutti, D.
    • Structural Engineering and Mechanics
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    • v.34 no.4
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    • pp.417-447
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    • 2010
  • The uncertainty often observed in experimental strengths of masonry constituents makes critical the selection of the appropriate inputs in finite element analysis of complex masonry buildings, as well as requires modelling the building ultimate load as a random variable. On the other hand, the utilization of expensive Monte Carlo simulations to estimate collapse load probability distributions may become computationally impractical when a single analysis of a complex building requires hours of computer calculations. To reduce the computational cost of Monte Carlo simulations, direct computer calculations can be replaced with inexpensive Response Surface (RS) models. This work investigates the use of RS models in Monte Carlo analysis of complex masonry buildings with random input parameters. The accuracy of the estimated RS models, as well as the good estimations of the collapse load cumulative distributions obtained via polynomial RS models, show how the proposed approach could be a useful tool in problems of technical interest.

Developed Ability of Zero-phase Overcurrent Relay by Changed setting point value (설정치 변경에 의한 영상과전류계전기의 성능개선)

  • Kim, N.H.;Yoon, D.S.;Chang, S.I.;Choi, J.H.
    • Proceedings of the KIEE Conference
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    • 1998.11a
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    • pp.220-222
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    • 1998
  • This paper presents a method, which develops an ability of Zero-phase Overcurrent Relay. Zero-phase current is very useful factor of Fault decision in Protect Relaying system. Actually, the setting-point value of Designed Relay, using Zero-phase current, is fixed. So in the case of deciding fault, Fixed setting-point value is not suitable for changing Load. and cause errors in Distributions system. For solving this problem, This paper proposes the Changed setting point value Algorithm, which can be adaptive for changing Distributions system using Zero-phase current r.m.s. indexes. The results of simulation under Load changing and High impedance fault show that proposed algorithm is useful for changing Distributions system and decreasing errors.

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