• Title/Summary/Keyword: relieving slab

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Evaluation of Minimum Depth Criterion and Reinforcement Effect of the Soil Cover in a Long-span Soil-steel Bridge (장지간 지중강판구조물의 최소토피고 평가 및 토피지반 보강에 대한 수치해석)

  • 이종구;조성민;정현식;김명모
    • Journal of the Korean Geotechnical Society
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    • v.20 no.5
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    • pp.67-78
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    • 2004
  • Soil-steel bridges are made of flexible corrugated steel plates buried in the well-compacted granular soil. One kind of possible collapses of these structures could be initiated by shear or tension failure in the soil cover subjected to vehicle loads. Current design codes provide the requirements for the minimum depth of the soil cover to avoid problems associated with soil cover failures. However, these requirements were developed for short span (less than 7.7 m) structures which are made of unstiffened plates of standard corrugation (150$\times$50 m). Numerical analyses were carried out to investigate the behavior of long span soil steel bridges according to thickness of the soil cover. The span of structures were up to 20 m and deep corrugated plates (381$\times$140 m) were used. The analysis showed that the minimum cover depth of 1.5 m could be sufficient to prevent the soil cover failure in the structures with a span exceeding 10 m. Additional analyses were performed to verify the reinforcement effect of the concrete relieving slab which can be a special feature to reduce the live-load effects. Analyses revealed that the bending moment of the conduit wall with a relieving slab was less than 20% of that without a relieving slab in a case of shallow soil cover conditions.

Evaluation of minimum depth of soil cover and reinforcement of soil cover above soil-steel bridge (지중강판 구조물의 최소토피고 평가 및 상부토피 보강 방안)

  • Jung, Hyun-Sik;Lee, Jong-Ku;Cho, Sung-Min;Kim, Myoung-Mo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.425-432
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    • 2004
  • In this paper, the results of the numerical analysis for the minimum depth of soil cover have been compared with those of currently suggested codes. Based on this comparison, the minimum depth of soil cover for the structures with long spans was suggested. Results showed that the actual depth of the soil cover required against soil failure over a circular and low-profile arch structure does not vary significantly with the size of the span and for the circular structure, the minimum depth of the soil cover was about 1.5m, and for the low-profile arch structures, below about 1.6m. And the previously established code in which the minimum depth of soil cover is defined to linearly increase with the increase in the span (CHBDC, 2001) was very conservative. For the structure with the relieving slab, the maximum live load thrust was reduced by about 36 percent and the maximum moment about 81 percent. The numerical analysis gave more conservative estimation of the live-load thrusts than the other design methods.

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Deformation of Corrugated Steel Plate Culverts in the Areas with Minimum Depth (최소토피고 미확보 구간에 시공한 파형강판 암거의 변형 특성)

  • Kim, Myoungil;Park, Duhee
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.7
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    • pp.23-30
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    • 2014
  • This paper deals with the characteristics of deformation of the underground corrugated steel plate culverts constructed in the areas where the minimum depth of within 1.5 m soil cover is not secured in the bottom of highways. The underground corrugated steel plate culverts at shallow depth are often designed and constructed with the consideration of the minimum depth of soil cover according to the design standards, which was made in order to minimize any deformation. Additionally, if under unfavorable conditions, slabs are set up for stress relaxation to disperse and minimize the weight of loads transferred to the corrugated steel plate culverts. Nevertheless, if the underground corrugated steel plate culverts are built in areas where the minimum depth of soil cover inevitably cannot be secured, there may occur some deformation. In this paper, a research was carried out to identify the characteristics of deformation in areas where the minimum depth of soil cover is not secured. The result shows that there existed the deterioration of pavement and in its smoothness around the corners of slabs for stress relaxation. To this end, this paper studied the structural stability of the underground corrugated steel plate culverts established in the areas with no minimum depth of soil cover secured, with the consideration of causes and solutions of pavement deterioration.