• Title/Summary/Keyword: Slab

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Equivalent boundary conditions to analyze the realistic fatigue behaviors of a bridge RC slab

  • Khan, Arslan Q.;Deng, Pengru;Matsumoto, Takashi
    • Structural Engineering and Mechanics
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    • v.82 no.3
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    • pp.369-383
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    • 2022
  • In this study, an equivalent boundary conditions (BCs) determination method is developed numerically for a panel reinforced concrete (RC) slab to realistically analyze the deformation and fatigue behaviors of a bridge RC slab. For this purpose, a finite element analysis of a bridge RC slab is carried out beforehand to calculate the stiffness of the bridge RC slab, and then the equivalent BCs for the panel RC slab are determined to achieve the same stiffness at the BCs to the obtained stiffness of the bridge RC slab at the corresponding locations of the bridge RC slab. Moreover, for the simulation of fatigue behaviors, fatigue analysis of the panel RC slab is carried out employing a finite element method based on a numerical model that considers the bridging stress degradation. Both the determined equivalent BCs and the BCs that have been typically applied in past studies are employed. The analysis results confirm that, in contrast to the panel RC slab with typically used BCs, the panel RC slab with equivalent BCs simulate the same bending moment distribution and deformation behaviors of the bridge RC slab. Furthermore, the equivalent BCs reproduce the extensive grid crack pattern in the panel RC slab, which is alike the pattern normally witnessed in a bridge RC slab. Conclusively, the panel RC slab with equivalent BCs behaves identical to the bridge RC slab, and, as a result, it shows more realistic fatigue behaviors observed in the bridge RC slab.

Influence of Slab Length on behavior of Floating Slab Track by Rail-slab-isolator Longitudinal Interaction

  • Nguyen, Huan Ha;Jang, Seung Yup;Chung, Wonseok
    • International Journal of Railway
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    • v.5 no.4
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    • pp.163-166
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    • 2012
  • Many different types of floating slab track have been developed and installed around the world to reduce vibrations and noise originating in the surrounding environment. The main objective of this study is to examine the influence of slab length on behavior of floating slab track based on rail-slab-isolator interaction. The floating slab track is modeled by the connection between rail, slab, isolator, and slab mat in the transition zone. All elements were assembled in a simplified two-dimensional (2D) finite element model (FEM). The maximum length of FST is then investigated based on the maximum additional rail stress criterion as described in UIC 774-3R since no fully accepted design criteria for the slab length in FST systems currently exist.

An Experimental Study on Structural Behavior of Half Slab Reinforced by Truss Mesh (트러서메쉬 보강 하프 슬래브의 구조적 거동에 관한 실험적 연구)

  • Ko, Man-Young;Kim, Yong-Boo;Park, Hyun-Soo;Chung, Lan
    • Magazine of the Korea Concrete Institute
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    • v.7 no.4
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    • pp.119-128
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    • 1995
  • This paper summarizes experimental results for studying feasibility and structural behavior of' a half slab which is getting popularity in recent building construction in favour of the savings in manpower, coats, and construction period. 17 specimens were tested to investigate and analyze the flexural strength of precast concrete slab, half slab, and half slab-wall joint. The primary variables of the testing program were: thickness of precast concrete slab, truss mesh shape, and type of loadings. Test results show that the flexural strength of precast concrete slab in reverse loading is lower than the design strength, but the flexural strength of precast concrete slab, half slab and half slab-wall joint in direct loading is higher than the design srength. No horizontal cracks were found in the connection between insitu concrete and precast concrete slab. The flexural strength of half slab and half slab-wall joint was the same as that of reinforced concrete members. This study concludes that there will not be any structural problem in using a half slab reinforced by truss mesh if props spacing of 2.0m-2.5m, cleanness, and rough finishing between precast concrete and insitu concrete slab are kept.

The Study of Improvement of the Void Slab Applying the Impedance Method (임피던스법을 이용한 보이드 슬라브의 개선방안에 관한 연구)

  • 오재응;김영식
    • Journal of KSNVE
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    • v.11 no.2
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    • pp.276-284
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    • 2001
  • In apartment buildings, floor-impact sound has been regarded as the major source that causes complaints from residents. It is mainly due to the use of light-weight structures and the lack of researches in terms of floor-impact sound. The purposes of this study are analyzing the characteristics of vibration response and sound radiation of 12type void slabs in the improvements void slab by impedance method and finding the fittest improvements void slab on the 12type void slab. The main results of this study are summarized as below: (1) In the $\frac{1}{3}$ octave band level of sound radiation, $\frac{1}{3}$ octave band levels, measured from four-divided improvement void slab(No.8) and eight-divided improvement void slab(No.12), are 10~25 dB lower than that of standard void slab(No.1) in the 1250 Hz. Especially, eight-divided improvement void slab(No.12) is the best void slab in terms of radiation efficiency of sound level. (2) In the correlation relation of acceleration and sound radiation, standard void slab(No.1), four-divided improvement void slab(No.8), SK standard four-hole void slab(No.10), and eight-divided improvement void slab(No.12) are positive correlation relation.

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Dynamic Characteristic of Post-tensioned Void Slab (포스트텐션 중공슬래브의 동적 특성)

  • Yoon, Sung-Won
    • Journal of Korean Association for Spatial Structures
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    • v.12 no.3
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    • pp.89-95
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    • 2012
  • Post-tensioned void slab is frequently used for improving the deflection and sound proofing. Two one story 8m spanned structures were built. One structure applied post-tensioned solid slab, but the other did post-tensioned void slab. Dynamic characteristics, which is natural frequency and damping ratio, was compared between that of solid slab and void slab before and after post tension. The natural frequency of void slab was greater than that of solid slab before and after post tension. It was shown that damping ratio of solid slab and void slab was almost same at two stages.

Characteristics of Middle Slab Stresses in Double-Deck Tunnel During Maintenance (복층터널 중간슬래브 유지관리에 따른 응력분포 특성 분석)

  • Cho, Young Kyo;Lee, Young Hoon;Park, Beom Keun;Kim, Seong-Min
    • International Journal of Highway Engineering
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    • v.19 no.6
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    • pp.47-56
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    • 2017
  • PURPOSES : The purpose of this study is to investigate the stresses of the middle slab in a double-deck tunnel owing to the slab lift to replace the underlying elastic pads during maintenance work. METHODS : The middle slab was divided into three different sections: typical section, expansion joint section, and emergency passageway section. Finite element analysis models of these three sections of middle slab were developed, and the stress distribution and maximum stresses were obtained using the models when the middle slab was lifted to replace the underlying elastic pads. Various slab lifting methods were examined in this study such as one-, two-, and multiple-point lifts, distributed lifts, and one or both slab side edge lifts. RESULTS : When the slab side edge is lifted, the longitudinal stresses of the slab are almost the same as the principal stresses. This implies that the governing stresses are the longitudinal stresses. The maximum stresses with both-edge lifts are generally smaller than those with one-edge lifts at all three sections of middle slab. CONCLUSIONS : If the middle slab in a double-deck tunnel is lifted for maintenance, the slab should be lifted at multiple points along the longitudinal direction to reduce the tensile stresses.

Dynamic Behavior of Train and Track at Slab Joints of Floating Slab Track (플로팅 슬래브궤도 슬래브 연결부에서의 차량 및 궤도의 동적 거동)

  • Jang, Seung-Yup;Yang, Sin-Chu;Hwang, Sung-Ho;Ahn, Mi-Kyung;Choi, Won-Il
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.993-997
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    • 2011
  • Highlighted is significance of the floating slab track for mitigating vibrations induced by train, together with the recent trends towards speed-up of railways. In the design of the floating slab track, it is more beneficial to increase the slab length since a significant impact can be induced on the train and track at the discontinuous points between slabs with the finite slab length. However, if the slab length is too long, the tensile stress of slab concrete and the additional stress on rail due to the temperature change and shrinkage of concrete slab. Thus it is of great importance to relevantly determine the slab length. In this study, to understand these phenomena and establish the countermeasures, the dynamic behaviors of train and track at the inter-slab discontinuous points have been explored and the effect of dowel joints as one of countermeasures has been analytically investigated.

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The Performance Evaluation of Newly Developed Concrete Slab Track (개발형 콘크리트 슬래브궤도의 성능평가)

  • Kang Yun Suk;Kim Eun;Lee Il Hwa;Yang Sin Chu
    • Proceedings of the KSR Conference
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    • 2003.10b
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    • pp.151-156
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    • 2003
  • The purpose of this study is to establish the test procedure of concrete slab track and to estimate the performance of newly developed slab track. The basic direction of conceptual design of KRRI Slab track was determined in the viewpoint of running safety, economic efficiency and maintenance costs. Based on the research results, a detailed conceptual design of KRRI slab track is suggested. For the systematic development of slab track, a comparative study is carried out, comparing merits and demerits of each slab type, and used in the design process of slab track. Slab track tests were performed at lab and the slab track system was improved by the experiment result. Site Test also were performed in test slab track.

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Prediction of Drying Shrinkage Behavior of Half PC Slab (Half PC slab의 건조수축 거동 예측)

  • Seo, Tae-Seok;Choi, Hoon-Jae
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.10a
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    • pp.7-8
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    • 2016
  • The use of half PC slab is increasing to shorten construction period. Because the drying shrinkage of topping concrete is restrained by PC slab, the tensile stress is generated at the topping concrete and the cracks can be occurred at the topping concrete due to drying shrinkage. Therefore, it is important to predict the tensile strain of half PC slab due to drying shrinkage to improve the quality of half PC slab. However, there is no studies on prediction of shrinkage behavior of half PC slab yet. Therefore, in this study, half PC slab was made, and the predictability of tensile strain generated at half PC slab due to drying shrinkage was investigated. The step by step method considering creep was used to estimate the tensile strain of half PC slab. In result, good agreement was obtained between the analytical and experimental values.

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Vibration Control and System Identification of Long Span Slab (대형 구조물 바닥판의 동적 거동 및 제어)

  • 황재승;김장윤
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.56-59
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    • 2003
  • As the slab is longer and lighter, it is more sensitive to the external force so that the vibration of slab and noise induced by the slab vibration is bigger than expected in normal slab. The purpose of this study is to investigate how the dynamic characteristic of slab is different from the normal slab through the system identification and tn evaluate the vibration control performance when the damper system is installed. Finally, we was trying to understand by what mechanism the slab noise is induced from the slab vibration. The relationship between the vibration and the noise of slab is shown by the numerical simulation.

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