• Title/Summary/Keyword: transverse stress

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Assessment of Incipient Decay of Radiata Pine Wood Using Stress-wave Technique in the Transverse Direction (횡단방향(橫斷方向) 응력파(應力波) 방법(方法)에 의(依)한 라디에타소나무의 초기부후(初期腐朽) 평가(評價))

  • Kim, Gyu-Hyeok;Jee, Woo-Guen;Ra, Jong-Bum
    • Journal of the Korean Wood Science and Technology
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    • v.24 no.3
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    • pp.18-27
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    • 1996
  • The feasibility of using stress-wave technique in the transverse direction for the assessment of early stages of decay was investigated using compression test specimens having different annual ring orientations subjected to decay by Tyromyces palustris for various time intervals. Decay detection, quantitative assessment of decay, and the prediction of residual strength of decayed wood with less than five percent weight loss can be feasible using stress-wave parameters (wave velocity, wave impedance, and stress-wave elasticity) and their percent reduction due to decay, measured by stress-wave technique in the transverse direction. The use of stress-wave technique in the transverse direction for the application of this technique to structural members in service is desirable, when considering the easiness of attachment of accelerometers of stress-wave measuring device on the surface of members and also accurate detection of localized decayed areas. In stress-wave technique in the transverse direction, stress-wave parameters measured were different according to the angles between wave propagation path and annual ring, due to the anisotropy of wood structure. Therefore, it is recommended to use percent reduction in stress-wave parameters instead of stress-wave parameters. This evaluation method using percent reduction in stress-wave parameters is ideal when it is impossible to observe annual ring orientation on the transverse surface of wood.

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Design Methodology of Transverse Post-Tensioning for Prestressed Concrete Pavements (프리스트레스트 콘크리트 포장의 횡방향 긴장 설계방안)

  • Kim, Seong-Min;Yoon, Dong-Joo;Bae, Jong-Oh
    • International Journal of Highway Engineering
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    • v.10 no.4
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    • pp.269-279
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    • 2008
  • This study was conducted to develop the design methodology of transverse post-tensioning for the prestressed concrete pavement (PSCP). The transverse stress distribution was analyzed when the transverse anchor spacing changed. The tensile stress distribution in the PSCP slab due to the environmental and vehicle loads was also investigated. The reasonable methods were discussed to determine the design loads including environmental and vehicle loads and the PSCP allowable tensile stress used for the basis of the selection of the stress application amount from the tensioning. The results of this study showed that as the transverse anchor spacing increased, the range of the stress loss became larger and the stress loss was significant near the shoulder. The design of the transverse post-tensioning can be performed by obtaining the stresses under the design loads and by considering the allowable tensile stress; however, the tensile stresses at different locations such as the shoulder, wheel pass, and slab interior should also be checked and kept below the allowable tensile stress.

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Effect of Distance and Restraint Degree between Fillet and Butt Weldment on Residual Stress Redistribution at each Weldment (필릿과 맞대기 용접부 간의 간격 및 구속도에 따른 잔류응력 재분포 특성에 관한 연구)

  • Jin, Hyung-Kook;Lee, Dong-Ju;Shin, Sang-Beom
    • Journal of Welding and Joining
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    • v.28 no.3
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    • pp.59-64
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    • 2010
  • The purpose of this study is to identify the principal factor controlling transverse residual stress at the weldment for joining unit hull blocks. In order to do it, the comprehensive FE analyses were carried out to evaluate the effect of distance between fillet and butt weldments, stiffener span and in-plane restraint degree on the amount and distribution of transverse residual stress in way of the weldments between unit hull blocks. In accordance with FEA results, principal factor controlling the amount of transverse residual stress at the weldments was identified as in-plane restraint degree of butt weldment for unit blocks. The effect of other variables on the transverse residual stress was very small relatively.

A Study on Load Transfer Efficiency of Skewed Transverse Joint of Concrete Pavement by the Fatigue Test (피로실험에 의한 콘크리트 포장체 경사가로줄눈부의 하중전달율에 관한 연구)

  • Hwang, Seung-Eui;Bae, Ju-Seong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.3
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    • pp.203-211
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    • 2001
  • This paper presents load transfer efficiency of skewed transverse joint of jointed concrete pavement with the fatigue model test. A 1/12 scale model was used to satisfy the geometry, loading, material similitude, which are variables to the skew angel of transverse joint. As the test results by fatigue load 700kgf applied, the deflection and stress of transverse joint were decreased as to increasing of skew angle of transverse joint. In addition, load transfer efficiency of transverse joint with skew angle is better than the load transfer efficiency of transverse joint without skew angle.

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Numerical Analysis of Prestressed Concrete Pavements Subjected to Transverse Post Tensioning (횡방향 긴장에 의한 프리스트레스트 콘크리트 포장의 거동분석)

  • Kim, Seong-Min;Yoon, Dong-Joo;Kim, Dong-Ho
    • International Journal of Highway Engineering
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    • v.10 no.4
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    • pp.257-267
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    • 2008
  • This study was conducted to investigate the stress distribution in the prestressed concrete pavement (PSCP) when the transverse post tensioning was applied. By performing the structural analyses using a finite element model of PSCP, the effect of anchor spacing and the relationship between the longitudinal and transverse post tensioning were evaluated. The analysis results showed that as the anchor spacing became smaller, the stresses were more uniformly distributed and the ranges of the stress losses were reduced; however, the economy should be considered. As the anchor spacing became larger, the difference between the average transverse stress and the transverse stresses at various locations such as shoulder, wheel pass, and center of the slab, increased. The transverse post tensioning induced the additional tensile forces in the longitudinal tendons, but the magnitude was negligibly small, and the longitudinal and transverse post tensioning could be designed independently. The use of the transverse stress distribution for the design of the post tensioning was also discussed in this paper.

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A Study on Evaluation of Residual Stress Redistribution for FCA Butt Weldment of Ultra-Thick YP47 Steel Plate under Tensile Cyclic Load (반복 인장 하중을 받는 YP47 극후판 Butt 용접부의 잔류응력 재분포에 관한 연구)

  • Kang, Bong Gook;Lee, Dong Ju;Shin, Sang Beom
    • Journal of Welding and Joining
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    • v.34 no.4
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    • pp.28-33
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    • 2016
  • The purpose of this study is to evaluate the redistribution of transverse residual stress in the multi-pass FCA butt weld of YP47 in the hatch coaming top plate of ultra large size containership under the tensile cyclic load. In order to do it, the configuration of modified H type specimen including restraint length was first designed to simulate the restraint condition of the butt weld in hatch coaming top plate. FE analysis procedure for evaluating the transverse residual stress was verified by comparing the calculated mean and surface residual stresses with the measured results in the test specimen. After that, the effect of the cyclic load on the redistribution of transverse residual stress was evaluated by comprehensive FEA. From the results, it was found that although the maximum transverse residual stress decreased with an increase in the applied maximum load, the effect of the cyclic load on the mean residual stress is small enough to be negligible. It is because the maximum stress of the ship corresponding to the probability of 10E-8 is less than 70% of yield stress of the weld.

A stress-strain Model of High-strength concrete confined with Transverse Reinforcement (횡보강철근으로 구속된 고강도 콘크리트의 응력-변형률 구속 모델)

  • Moon, Cho-Hwa;Park, Jong-Wook;Kim, Sang-Woo;Kim, Kil-Hee;Lee, Jung-Yoon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.87-88
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    • 2010
  • The strength and ductile capacity of reinforced concrete column can be improved by confinement using transverse reinforcement. Variety stress-strain models about the reinforced concrete confined by transverse reinforcement has been proposed. In this paper, parameters which effect to the ultimate confinement stress of circular cylinder confined by high strength transverse steel is examined. And the possion's ratio equation is proposed by analysis of strain between concrete and transverse reinforcement.

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Evaluation of the delamination strengths in differently processed practical Ag-stabilized REBCO CC tapes under transverse loading

  • Diaz, Mark A.;Shin, Hyung-Seop;Ha, Hongsoo;Oh, Sang-Soo
    • Progress in Superconductivity and Cryogenics
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    • v.21 no.4
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    • pp.34-38
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    • 2019
  • Multilayered high-temperature superconductor coated conductor (CC) tapes are used in an extensive range of applications and are exposed to many stresses such as hoop stress, radial/transverse tensile stress under large Lorentz forces, and thermal stress while cooling if thermal expansion properties differ. Loads induced transversely at the tape surface inevitably create delamination phenomena in the multilayered CC tapes. Thus, delamination behaviors of CC tapes along the c-axis under transverse loading conditions, which can vary based on manufacturing process and constituent layers, must be characterized for applications. The anvil test method was used to mechanically investigate the delamination characteristics of various commercially available Ag-stabilized CC tapes at room temperature and 77 K, finding superior strength at the latter. The wide variations found depended on tape structure and fabrication technique. Fractographic morphologies of delaminated tapes supported the findings under transverse loading conditions.

Study on Residual Stress Redistribution by Changing of Distance and Restraint degree between Fillet and Butt weldment (필렛 및 맞대기 용접부의 간격 및 구속도에 따른 잔류응력 재분포 특성에 관한 연구)

  • Jin, Hyung-Kook;Lee, Dong-Ju;Shin, Sang-Beom
    • Proceedings of the KWS Conference
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    • 2009.11a
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    • pp.94-94
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    • 2009
  • The purpose of this study is to identify the principal factor controlling transverse residual stress at the weldment for joining unit hull blocks. In order to do it, the comprehensive FE analyses were carried out to evaluate the effect of distance between fillet and butt weldments, in-plane and out-of-plane restraint degree on the amount and distribution of transverse residual stress in way of the weldments between unit hull blocks. In accordance with FEA results, principal factor controlling the amount of transverse residual stress at the weldments was identified as in-plane restraint degree of butt weldment for unit blocks. The effect of other variables on the transverse residual stress was very small relatively. Based on the results, it can be concluded that the proper distance between fillet weldment for stiffener and butt weldment for joining unit blocks should be determined in consideration of in-plane restraint intensity of butt weldments.

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Analysis of Longitudinal Steel Behaviors of Continuously Reinforced Concrete Pavement at Early Age (연속철근콘크리트(CRCP) 종방향 철근의 초기거동 분석)

  • Nam, Jeong-Hee;Jeon, Sung Il
    • International Journal of Highway Engineering
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    • v.16 no.6
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    • pp.59-67
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    • 2014
  • PURPOSES : The purpose of this study is to analyse the longitudinal steel strain and stress of continuously reinforced concrete pavement(CRCP) with longitudinal and transverse direction at early age using stress dependent strain analysis method. METHODS : To measure the longitudinal steel strain, 9-electrical resistance and self-temperature compensation gauges were installed to CRCP test section (thickness = 250mm, steel ratio = 0.7%) and continuously measured 10min. intervals during 30days. In order to properly analyze the steel stress first, temperature compensation process has been conducted. Secondly, measured steel strains were divided into stress dependent strain (elastic strain) and stress independent strain (thermal strain) and then stress dependent strain was applied to stress calculation of longitudinal steels. RESULTS : Steel strains were successfully measured during 30days. To verify the accuracy of temperature compensation process, measured coefficient of thermal expansion(COTE,$11.46{\times}10^{-6}m/m/^{\circ}C$) of longitudinal steel before paving was compared with that of unrestrained steel. Max. steel stress in the transverse direction shows about 266MPa at 23days after placement. CONCLUSIONS : Steel stresses in the longitudinal and transverse direction have been evaluated. In longitudinal direction, steel stress from the crack was rapidly reduced from 183MPa at crack to 18MPa from 600mm apart the crack. From this observation, stress effective length can be identified as within 600mm apart from the crack. In transverse direction, max. stress point was located near the center of pavement width and stress level(266MPa) is about 66% of yield stress of steel.