• Title/Summary/Keyword: Live Load

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Structural behavior of cable-stayed bridges after cable failure

  • Kim, Seungjun;Kang, Young Jong
    • Structural Engineering and Mechanics
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    • v.59 no.6
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    • pp.1095-1120
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    • 2016
  • This paper investigates the change of structural characteristics of steel cable-stayed bridges after cable failure. Cables, considered as the intermediate supports of cable-stayed bridges, can break or fail for several reasons, such as fire, direct vehicle clash accident, extreme weather conditions, and fatigue of cable or anchorage. Also, the replacement of cables can cause temporary disconnection. Because of the structural characteristics with various geometric nonlinearities of cable-stayed bridges, cable failure may cause significant change to the structural state and ultimate behavior. Until now, the characteristics of structural behavior after cable failure have rarely been studied. In this study, rational cable failure analysis is suggested to trace the new equilibrium with structural configuration after the cable failure. Also, the sequence of ultimate analysis for the structure that suffers cable failure is suggested, to study the change of ultimate behavior and load carrying capacity under specific live load conditions. Using these analysis methods, the statical behavior after individual cable failure is studied based on the change of structural configuration, and distribution of internal forces. Also, the change of the ultimate behavior and load carrying capacity under specific live load conditions is investigated, using the proposed analysis method. According to the study, significant change of the statical behavior and ultimate capacity occurs although just one cable fails.

Structural Analysis of a Cable Anchor System for a Cable-Stayed Bridge over the Sea (해상 사장교의 Pipe형 케이블 정착구에 관한 구조해석)

  • KONG BYUNG-SEUNC;HONG NAMSEEG
    • Journal of Ocean Engineering and Technology
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    • v.19 no.5 s.66
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    • pp.34-42
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    • 2005
  • The cable connection zone of the cable-stayed bridge transfers deal-load, live-load, and second-load to the cables on the structural joint zone of the cables and the main girders are the most critical parts in which big cable tensile forces are generated by those loads. Therefore, it is necessary to thoroughly check the main girder, structurally to secure the required stability. Because of the heavy tensile force of cables linked in the connection zone of the cable-stayed bridge, locally concentrated stress, as well as the dispersion of stress, occurs in the structurally contacted point of cable and main girder thus, we need to make a thorough investigation through a detailed structural analysis. Directly delivering the tensile force to the connection zone of the cable, the consequently big effect in the tensile force fluctuation caused by the live-load will make it necessary to review the fatigue strength. As the connection zone of the cable is designed to resist the tensile force of the cable, which is applied to a connecting section as a concentrated force, thick plates are used. These plates are frequently made of welded structure, thus, the investigation of the welding workability is inevitable.

Probabilistic analysis of RC beams according to IS456:2000 in limit state of collapse

  • Kulkarni, Anadee M.;Dattaa, Debarati
    • Structural Engineering and Mechanics
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    • v.71 no.2
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    • pp.165-173
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    • 2019
  • This paper investigates the probability of failure of reinforced concrete beams for limit state of collapse for flexure and shear. The influence of randomness of the variables on the failure probability is also examined. The Indian standard code for plain and reinforced concrete IS456:2000 is used for the design of beams. Probabilistic models are developed for flexure and shear according to IS456:2000. The loads considered acting on the beam are live load and dead load only. Random variables associated with the limit state equation such as grade of concrete, grade of steel, live load and dead load are identified. Probability of failure is evaluated based on the limit state equation using First Order Reliability Method (FORM). Importance of the random variables on the limit state equations are observed and the variables are accordingly reduced. The effect of the reduced parameters is checked on the probability of failure. The results show the role of each parameter on the design of beam. Thus, the Indian standard guidelines for plain and reinforced concrete IS456:2000 is investigated with the probabilistic and risk-based analysis and design for a simple beam. The results obtained are also compared with the literature and accordingly some suggestions are made.

Probabilistic Analysis of Lifetime Extreme Live Loads of Multi-Story Columns (고층기둥 축하중의 사용기간 최대값에 대한 확률론적 분석)

  • 김상효;박흥석
    • Computational Structural Engineering
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    • v.5 no.3
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    • pp.113-118
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    • 1992
  • The live loads acting on structures are generally computed in terms of equivalent uniformly distributed loads for the simplicity in design process. The loads, therefore, tend to decrease with increasing influence area in both load intensity and variance. Since multi-story column loads result from accumulation of loadings action on several different floors, its influence area becomes wider and lifetime maximum decreases. In the design codes proposing the design loads according to types of structural members(i.e., slabs, beams, columns), rather than the change of influence area, some proper reduction factors are given for columns which support more than one floor. Using the live load models developed for columns supporting single floor, in this study, the probabilistic characteristics of multi-story column loads are analyzed. In addition reduction factors given for multistory columns in current practice are calibrated.

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Probabilistic Analysis of Lifetime Extreme Live toads of Multi-Story Columns (고층기둥 축하중의 사용기간 최대값 분석)

  • 김상효;조형근;배규웅;박홍석
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1990.10a
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    • pp.69-72
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    • 1990
  • The live loads acting on structures are generally computed in terms of equivalent uniformly distributed loads for the simplicity in design process. The loads, therefore, tend to decrease with increasing influence area in both load intensity and variance. Since multi-story column loads result from accumulation of loadings acting on several different floors, its influence area becomes wider and lifetime maximum decreases. In the design codes proposing the design loads for types of structural members (i.e., slabs, beams, columns), not for tile change of influence area, some proper reduction factors are given for columns which support more than one floor. Using the live load models developed for colons supporting single floor, in this study, the probabilistic characteristics of multi-story column loads are analyzed. In addition reduction factors given for multi-story columns in current practice are calibrated.

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The Standard for Installation of Automated Distribution Switch-gear in Multi-Line Faults (다중선로 고장을 고려한 배전자동화용 개폐기 설치기준)

  • Lee, Jung-Ho;Ha, Bok-Nam;Cho, Nam-Hun;Lim, Sung-Il
    • Proceedings of the KIEE Conference
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    • 1999.07c
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    • pp.1079-1081
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    • 1999
  • This paper presents the standard for dividing/tieing the distribution lines and installing optimally the automated distribution switch-gear in multi-line faults. Also this paper recommends the distribution system design in consideration of the live load transfer of the concentrated load in the last load-side. This recommendation will be useful for designing the distribution network, developing the feeder automation software and operating the distribution automation system.

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A Study on the Axis Line of Short Span Filled Spandrel Arch Bridge (단경간 폐복식 아치교의 축선에 관한 연구)

  • 구민세;황윤국;조현준
    • Proceedings of the Korea Concrete Institute Conference
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    • 1990.10a
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    • pp.95-100
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    • 1990
  • The behavior of short span filled spandrel arch bridge of 10 and 21 m span with various axis line, rise and backill height were investigated under the design loads(self weight, earth pressure, temperature load, live load, etc). Even though the behaviors of arch were known as relatively complicated, the followings can be concluded within the limits of this study. The design value of arch bridge increase as the rise decreases, the effects of temperature load become dominant for the design of arch bridge, and governing design factors are occured at springing.

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Comparison of reaction force and contact pressure on design truck load of slab bridge supported by MSEW abutment (보강토교대로 지지된 슬래브교의 설계 활하중에 대한 반력 및 접지압 검토)

  • Kim, Hong-Bae;Han, Heui-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.5
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    • pp.510-519
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    • 2019
  • In this study, the structural analysis was conducted to the comparison of reaction force and contact pressure on the design truck load (DB-24 and KL-510) of slab bridge supported by MSEW abutment. As a result of the structural analysis, the reaction force acting on the abutment at the continuous bridge was reduced rather than the simple span bridge. The reaction force due to the dead load was estimated to be about twice as large as that of the live load, and the influence of the live load on the total reaction force was relatively small. The contact pressure of the MSEW abutment was estimated to be the largest in the simple span bridge. The influence of contact pressure on the type of live load was relatively small. Therefore, it is considered to be more advantageous to apply the MSEW abutment to the continuous bridge than to the simple span bridge because the contact pressure acting on the abutment on the continuous bridge is estimated to be small. Since the reaction force and the load sharing ratio acting on the MSEW abutment depending on various conditions, it is necessary to examine the contact pressure in various types of bridges and specifications.

Optimal Tension Forces of Multi-step Prestressed Composite Girders Using Commercial Rolled Beams (상용압연 형강과 콘크리트 합성거더의 다단계 긴장력 최적설계)

  • 정홍시;김영우;박재만;신영석
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2004.04a
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    • pp.95-102
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    • 2004
  • The 1st and 2nd tension forces of the PSSC(Prestressed Steel and Concrete) girder constructed with commercial rolling beams and concrete are optimally designed. The design variables are the 1st and 2nd tension forces due to multi-step prestressing and live load. The objective function is set to the maximum live load. Design conditions are allowable stress at the top and bottom of slab, beam and infilled concrete due to a construction step. An Optimization of Matlab based program Is developed. The results show that the tendon position and concrete compression strength etc are important.

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A Study on the Development of the Wheel Tracking Test and Evaluation Method on Blind Type of Waterproofing Layer (비노출 방수층의 윤하중 시험 및 평가방법 개발에 관한 실험적 연구)

  • Song Je-Young;Eom Deok-Jun;Kwak Kyu-Sung;Oh Sang-Keun
    • Journal of the Korea Institute of Building Construction
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    • v.6 no.1 s.19
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    • pp.67-72
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    • 2006
  • There are a lot of problem about waterproofing membrane coating for concrete deck of bridge and waterproofing sheets for concrete of deck of bridge because it couldn't confirm waterproofing's defeat after construction. These problems make a waterproofing material damage and condrete deck of bridge damage. So It needs a lot of money for repair work and reinforcement work. Therefor the structure slab of using waterproofing material protect invasion of water. Also, Concrete deck of bridge need a endurance permeability for the reduction repair payment. In this study, An experimental study on the quality standardization test method waterproofing layer on working of live load.