• Title, Summary, Keyword: 접속슬래브

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Evaluation on Bending Moment of Bridge Approach Slabs under Vehicle Load Considering Soil Settlement (지반침하를 고려한 교량 접속판의 차량하중에 의한 휨모멘트 평가)

  • Back, Sung-Yong;Kim, Jung-Gang;Cho, Baik-Soon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.11
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    • pp.5939-5946
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    • 2013
  • The bridge approach slabs (BAS) to provide a transitional roadway between a roadway pavement and a bridge structure have not performed adequately due to various factors. The current Korean Roadway Design Guidelines treat the BAS as a simply supported beam with 70% of the span length and do not consider settlement and void development underneath the slab. To investigate the effect of soil settlements on the bending moment of BAS, a beam on elastic support (BAS-ES) was used in the present study. The parameters used in this study were span length, washout length, washout location, and soil modulus. It was shown from the parametric study that washout regions closer to the midspan exhibit maximum moment in the slab. Since voids under the BAS have typically been observed to be closer to bridge abutments, the springs from the abutment were removed to simulate settlement and void development in the model. The design moments based on AASHTO LRFD Bridge Design Specifications were compared to those of Korean Standard Specifications for Highway Bridge and Design Trucks for Highway Bridges. Even if the design moment from BAS-ES was used to incorporate the effect of the potential washout, significant savings could still be achieved compared to the current BAS design.

Behavior and Design of Terminal Joint Width between Post-Tensioned Concrete Pavement and Jointed Concrete Pavement under Temperature Changes (온도변화에 따른 PTCP와 JCP 접속부 줄눈 폭 변화와 설계 방안)

  • Kim, Dong-Ho;Lee, Bong-Hak;Kim, Seong-Min;Park, Seong-Tae
    • International Journal of Highway Engineering
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    • v.13 no.1
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    • pp.223-228
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    • 2011
  • The initial joint width design of the terminal joint between post-tensioned concrete pavement (PTCP) and jointed concrete pavement (JCP) was studied in this research. The joint width between PTCP and JCP directly affects noise and ride quality. If the initial joint width is very large, noise increases and ride quality decreases. If the initial joint width is very small, on the other hand, under high temperatures, PTCP slabs can blow up, or failures near the joint can occur due to excessive compressive stresses. The terminal joint width behavior between PTCP and JCP near Jumunjin at Donghae expressway under temperature changes was measured in August and November 2010 and the data was analyzed. From this study, the design methodology of the optimal initial terminal joint width was proposed.

Analysis of Behavior of Train and Track at Transition Zone between Floating Slab Track and Conventional Concrete Slab Track (플로팅 슬래브궤도와 일반 콘크리트궤도 접속부에서의 열차 및 궤도의 거동 분석)

  • Jang, Seung-Yup;Yang, Sin-Chu;Park, Man-Ho;Joh, Su-Ik
    • Proceedings of the KSR Conference
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    • pp.379-384
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    • 2009
  • It is of great importance to assure the running safety and ride comfort in designing the floating slab track for the mitigation of train-induced vibration. In this paper, for this, analyzed are the system requirements for the running safety and ride comfort, and then, the behavior of train and track at the transition zone between the floating slab track and the conventional concrete slab track according to several main design variables such as spring constant, damping coefficient, spacing and arrangement of isolators and slab length, using the dynamic analysis technique considering the train-track interaction. The results of numerical analysis demonstrate that the discontinuity of the support stiffness at the transition results in a drastic increase of the vertical vibration acceleration of the train body, wheel-rail interaction force, rail bending stress and uplift force. The increase becomes higher with the decrease of the spring constant of isolators and the increase of the isolator spacing, but the damping ratio does not significantly affect the behavior of train and track at the transition. Therefore, to assure the running safety and ride comfort, simultaneously increasing the effectiveness of vibration isolation, it is effective to minimize the relative vertical offset between the floating slab and the conventional track slab by adjusting the spring constant and spacing of isolators at the transition.

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A study on structural performance of steel brackets in vertical shaft connected to double-deck tunnel (복층터널 연결 수직구용 철재브래킷 구조성능 연구)

  • Shin, Young-Wan;Min, Byeong-Heon;Nam, Jung-Bong;Lee, Sang-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.3
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    • pp.363-375
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    • 2019
  • Since the double-deck tunnel is deeply constructed in the city, it is necessary to secure the installation space of air supply and exhaust, escape passage stairs, elevator, distribution facilities and connection tunnels in the vertical shaft for the double-deck tunnel. Also, in order to minimize the effect of construction on adjacent area, it is necessary to construct the concrete structures at high speed in vertical shaft after tunnel excavation. Therefore, the slabs and the stairs in vertical shaft are needed to be constructed using precast concrete, and the rapid construction techniques of bracket for supporting the inner precast structure are needed. The bracket installation methods include cast-in-place concrete, precast concrete and steel. In this study, the improvement of the steel brackets with good economical efficiency and good workability was carried out in consideration of the improvement of the construction speed. We have developed a new bracket that is optimized through bracket shape improvement, anchor bolt position adjustment and quantity optimization. As a result of the structural performance test, it was confirmed that the required load supporting capacity was secured. As a result of structural performance test for bar type anchor bolt and bent anchor anchor bolt, it was confirmed that the required load carrying capacity was secured and that the load bearing capacity of bent anchor bolt was large.