• Title/Summary/Keyword: longitudinal reinforcement

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A fast and robust procedure for optimal detail design of continuous RC beams

  • Bolideh, Ameneh;Arab, Hamed Ghohani;Ghasemi, Mohammad Reza
    • Computers and Concrete
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    • v.24 no.4
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    • pp.313-327
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    • 2019
  • The purpose of the present study is to present a new approach to designing and selecting the details of multidimensional continuous RC beam by applying all strength, serviceability, ductility and other constraints based on ACI318-14 using Teaching Learning Based Optimization (TLBO) algorithm. The optimum reinforcement detailing of longitudinal bars is done in two steps. in the first stage, only the dimensions of the beam in each span are considered as the variables of the optimization algorithm. in the second stage, the optimal design of the longitudinal bars of the beam is made according to the first step inputs. In the optimum shear reinforcement, using gradient-based methods, the most optimal possible mode is selected based on the existing assumptions. The objective function in this study is a cost function that includes the cost of concrete, formwork and reinforcing steel bars. The steel used in the objective function is the sum of longitudinal and shear bars. The use of a catalog list consisting of all existing patterns of longitudinal bars based on the minimum rules of the regulation in the second stage, leads to a sharp reduction in the volume of calculations and the achievement of the best solution. Three example with varying degrees of complexity, have been selected in order to investigate the optimal design of the longitudinal and shear reinforcement of continuous beam.

Analytical Study on the Improvement of Fatigue Strength for the Orthotropic Steel Decks with Reinforced Structural Details (보강상세 적용에 따른 강바닥판 피로강도 향상에 관한 해석적 연구)

  • Kyung, Kab-Soo;Park, Kyung-Jin;Kin, Kyo-Hoon;Park, Hye-Yeon
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.839-844
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    • 2007
  • In order to reduce resultant stress of the connection detail of longitudinal and rib and floor beam, in this study, the parameter studies for the reinforcement details as the bulk head and the vertical rib were preformed with FE analysis. As the result, it was shown that reinforcement detail with the bulk head plate in longitudinal rig reduced generally the principal stress at the connection detail, but the stress concentration of the weld toe parts occurring fatigue crack increased. However, it was known that the reinforcement detail with the vertical rib in the rib is more effective than the bulk head plate of the reduction stress concentration in the weld toe parts.

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Optimum Seismic Design of Reinforced Concrete Piers Considering Economy and Constructivity (내진설계시 경제성 및 시공성을 고려한 RC 교각의 최적설계)

  • 조병완;김영진;윤은이
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.479-484
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    • 2000
  • In this study, optimal design of reinforced concrete piers under seismic load is numerically investigated. Object function is the area of the concreate-section. Design variables are the total area of reinforcement and concrete-section dimension(Circular section diameter). Constraints of the design strength of the column, longitudinal reinforcement ratio and lower and upper bounds on the design variables are imposed. The reinforcement concrete column is analysed and designed by the Ultimated Strength Design method and load combination involving dead, live, wind and seismic load is used. For numerical optimization, ADS(Garret N, Vanderplaats_ routine is used. From the result of numerical examples, the concrete-section dimension was reduced, but longitudinal reinforcement was not changed. The results show that confinement reinforcement was reduced and confinement reinforcement spacing is increased. The higher strength of reinforcement used, the more concrete-section area was reduced.

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A Characteristic Study on Shear Strength of Reinforced Concrete Beams according to Longitudinal Reinforcement Ratio and Size Effect (철근콘크리트보의 인장철근비와 크기효과에 의한 전단강도 특성 연구)

  • Yu, In-Geun;Noh, Hyung-Jin;Lee, Ho-Kyung;Baek, Seung-Min;Kim, Woo-Suk;Kwak, Yoon-Keun
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.36 no.2
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    • pp.117-126
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    • 2020
  • The main objective of this experimental study is to investigate shear strength of reinforced concrete beams according to longitudinal reinforcement ratio (ρ) and size effect. In order to find out the shear strength according to the tensile reinforcement ratio, in particular, the main variables are 100%, 75% and 50% of ρ=0.01 which is widely used in construction field. A total of twelve RC beams were tested under 4-point loading conditions. In addition to the existing proposal equations, the theoretical values such as KBC and ACI equations are compared with the experimental data. Through this analysis, this study is designed to provide more reasonable equations for shear design of reinforced concrete beams. When shear reinforcement bar spacing of nine specimens (R*-1, R*-2, and R*-3 series) fixed as d/s=2.0 and three specimens of R*-4 series fixed as d/s=1.5 are compared, the shear strength of two groups showed similar values. As a result, the current standard of d/s=2.0 for shear reinforcement bar spacing may be somewhat alleviated.

Evaluation of Longitudinal Steel Tension in Shear-Critical RC Beams (전단이 지배하는 RC 보의 주철근 인장력 산정)

  • Jeong, Jae-Pyong;Kim, Dae-Joong;Kim, Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.252-255
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    • 2004
  • The measured longitudinal reinforcement tensions in the shear-critical RC beams were significantly higher than the calculated values by the beam theory. This may be attributed to the reduction of the internal-moment arm length by the development of the arch action. In this paper, the measured longitudinal reinforcement tensions in the test performed by $Kim^4$ were compared with those predicted by the various truss model.

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Predictoin of Longitudinal Steel Tension for Shear-Critical Reinforced Concrete Beams with Stirrups (전단이 지배하는 철근콘크리트 보의 주철근 인장력 산정)

  • Rhee, Chang-Shin;Byun, Su-Min;Shin, Geun-Ok;Kim, Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05a
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    • pp.374-377
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    • 2006
  • The measured longitudinal reinforcement tensions in the shear-critical RC beams were significantly higher than the calculated values by the beam theory. This may be attributed to the reduction of the internal-moment arm length by the development of the arch action. In this paper, the measured longitudinal reinforcement tensions in the test performed by Kim were compared with those predicted by the new truss model on the basis of the compatibility condition of the shear deformation.

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Experimental investigations of the seismic performance of bridge piers with rounded rectangular cross-sections

  • Shao, Guangqiang;Jiang, Lizhong;Chouw, Nawawi
    • Earthquakes and Structures
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    • v.7 no.4
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    • pp.463-484
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    • 2014
  • Solid piers with a rounded rectangular cross-section are widely used in railway bridges for high-speed trains in China. Compared to highway bridge piers, these railway bridge piers have a larger crosssection and less steel reinforcement. Existing material models cannot accurately predict the seismic behavior of this kind of railway bridge piers. This is because only a few parameters, such as axial load, longitudinal and transverse reinforcement, are taken into account. To enable a better understanding of the seismic behavior of this type of bridge pier, a simultaneous influence of the various parameters, i.e. ratio of height to thickness, axial load to concrete compressive strength ratio and longitudinal to transverse reinforcements, on the failure characteristics, hysteresis, skeleton curves, and displacement ductility were investigated. In total, nine model piers were tested under cyclic loading. The hysteretic response obtained from the experiments is compared with that obtained from numerical studies using existing material models. The experimental data shows that the hysteresis curves have significantly pinched characteristics that are associated with small longitudinal reinforcement ratios. The displacement ductility reduces with an increase in ratio of axial load to concrete compressive strength and longitudinal reinforcement ratio. The experimental results are largely in agreement with the numerical results obtained using Chang-Mander concrete model.

An Experimental Study on the Behavior of Reinforced Concrete Multi-Column Piers with Different Longitudinal and Transverse Reinforcement Details (주철근 겹침이음 및 횡철근 상세에 따른 철근콘크리트 다주교각의 거동특성에 관한 실험적 연구)

  • 김재관;김익현;김정한;조대연
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.03a
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    • pp.211-219
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    • 2002
  • This study is performed to investigate the behavior of multi-column piers and to evaluate the seismic performance. In this study, 3 types of scale model piers with 2-column are designed and tested by quasi-static load in both longitudinal and transverse directions. Each type of model consisting of 2 specimens has different reinforcement details in the lap splice of longitudinal bars and amount of transverse reinforcements. This paper reports that the ductility of the model in transverse direction is rather higher than in longitudinal direction because of formation of several plastic hinges and that the ultimate displacement and the energy absorbtion capacity are enhanced by using continuous longitudinal bars instead of lap-splice ones. And it is confirmed that relatively large amount of ductility can be achieved by providing sufficient lap-splice length and transverse reinforcements with end hook even if longitudinal bars are lap spliced in the base of pier.

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The Experimental Study on Seismic Performance of RC Bridge Columns with Longitudinal Steel Lap Splice (겹침이음 상세에 따른 철근콘크리트 교각의 내진성능에 관한 실험적 연구)

  • 석상근;손혁수;정철호;이재훈
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.553-558
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    • 2001
  • Recent destructive seismic events demonstrated the importance of mitigating human casualties and serious property damages in design and construction of structures. The Korean Bridge Design Specifications (1992) adopted seismic design requirements based on the AASHTO specification, and minor modification was made in 2000. The longitudinal steel connection of reinforced concrete bridge column is sometimes practically unavoidable. The longitudinal reinforcement details affect seismic performance such as flexural failure and shear failure. This research aims to develop longitudinal steel connection details with confinement steel by experimental study for seismic performance of reinforced concrete bridge columns. Quasi-static test under three different axial load levels was conducted for 12 spiral column specimens. All the column specimens had the same aspect ratio of 3.5. The column specimens were transversely reinforced with spiral and with five different longitudinal steel connection. The final objective of this study is to suggest appropriate longitudinal reinforcement connection details for the limited ductility design concept and improve construction quality.

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Seismic Performance of RC Bridge Columns with Longitudinal Steel Lap Splice (겹침이음 상세에 따른 철근콘크리트 교각의 내진성능)

  • 이재훈;손혁수;석상근;정철호
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.04a
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    • pp.345-352
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    • 2001
  • Recent destructive seismic events demonstrated the importance of mitigating human casualties and serious property damages in design and construction of structures. The Korean Bridge Design Specifications (1992) adopted seismic design requirements based on the AASHTO specification, and minor modification was made in 2000. The longitudinal steel connection of reinforced concrete bridge column is sometimes practically unavoidable. The longitudinal reinforcement details affect seisimc performance such as flexural failure and shear failure. This research aims to develop longitudinal steel connection details with confinement steel by experimental study for seismic performance of reinforced concrete bridge columns. Quasi-static test under three different axial load levels was conducted for 12 spiral column specimens. All the column specimens had the same aspect ratio of 3.5. The column specimens were transversely reinforced with spiral and with five different longitudinal steel connection. The final objective of this study is to suggest appropriate longitudinal reinforcement connection details for the limited ductility design concept and improve construction quality.

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