• Title, Summary, Keyword: Precast concrete segment lining

Search Result 4, Processing Time 0.083 seconds

Fire Resistance Performance of Precast Segmental Concrete Lining for Shield Tunnel (쉴드 터널용 프리캐스트 세그먼트 콘크리트 라이닝의 내화성능)

  • Han, Byung-Chan;Harada, kazunori;Kwon, Young-Jin;Kim, Yun Yong
    • Journal of The Korean Society of Civil Engineers
    • /
    • v.34 no.1
    • /
    • pp.95-105
    • /
    • 2014
  • Reinforced concrete (RC) shield tunnel lining must be designed for fireproof performance because the lining is sometimes exposed to very high temperature due to traffic accidents. Both experimental and numerical studies are carried out to evaluate fire resistance performance of precast RC tunnel lining systems. In the experimental studies, six full-scale precast RC tunnel segments are exposed to fire in order to examine the influence of various parameters on the fire resistance performance of precast RC tunnel lining. We used the temperature curve of the RABT criteria, which are severe conditions of fire temperatures. The fire test showed that the explosive spalling was not observed by substituting concrete to PP fiber reinforced concrete. A transient heat flow analysis was carried out in consideration of the material properties that change with temperature, and the results showed good agreement with the test results.

Structural performance evaluation of precast concrete segment using synthetic fibres (프리캐스트 콘크리트 세그먼트의 합성섬유 보강재 적용에 따른 구조적 성능 평가)

  • Lee, Hoseong;Kim, Changyong;Lee, Sean S.;Kim, Seungjun;Lee, Kyeongjin
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.20 no.2
    • /
    • pp.469-483
    • /
    • 2018
  • Steel bars have been widely used as the primary reinforcement for Precast Segmental Concrete Lining for TBM Tunnels. Previously, studies have been carried out to gauge the potential for steel fiber reinforcement to replace the use of steel bar reinforcements in the segmental lining to reduce the amount of the steel bar reinforcement. Steel fiber reinforcements have been investigated and widely applied to SFRC TBM linings to improve the constructability of SFRC TBM linings worldwide. However, the steel fiber reinforcement often caused punctures to the water membranes inside tunnel lining and had long-term durability deterioration issues caused by steel corrosion, as well as cosmetic problems. Therefore, this paper sought to gauge the potential of synthetic fiber reinforcements, which have proven to be very attractive substitutes for steel fiber reinforcements. This study analyzed the performance of both steel and synthetic fiber reinforcements in segmental linings and evaluated the applicability of the fiber reinforcements to the TBM Precast Concrete Segmental Linings of TBM tunnels. As a conclusion, this study demonstrates that the potential use of steel and synthetic fibers in various combination, can substitute the rebar reinforcement in the concrete mix for segmental concrete linings.

The structural analysis and design methods considering joint bursting in the segment lining (조인트 버스팅을 고려한 세그먼트 라이닝 구조해석 및 설계방법)

  • Kim, Hong-Moon;Kim, Hyun-Su;Jung, Hyuk-Il
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.20 no.6
    • /
    • pp.1125-1146
    • /
    • 2018
  • Segment lining applied to the TBM tunnel is mainly made of concrete, and it requires sufficient structural capacity to resist loads received during the construction and also after the completion. When segment lining is design to the Limit State Design, both Ultimate Limit State (ULS) and Service Limit State (SLS) should be met for the possible load cases that covers both permanent and temporary load cases - such as load applied by TBM. When design segment lining, it is important to check structural capacity at the joints as both temporary and permanent loads are always transferred through the segment joints, and sometimes the load applied to the joint is high enough to damage the segment - so called bursting failure. According to the various design guides from UK (PAS 8810, 2016), compression stress at the joint surface can generate bursting failure of the segment. This is normally from the TBM's jacking force applied at the circumferential joint, and the lining's hoop thrust generated from the permanent loads applied at the radial joint. Therefore, precast concrete segment lining's joints shall be designed to have sufficient structural capacity to resist bursting stresses generated by the TBM's jacking force and by the hoop thrust. In this study, bursting stress at the segment joints are calculated, and the joint's structural capacity was assessed using Leonhardt (1964) and FEM analysis for three different design cases. For those three analysis cases, hoop thrust at the radial joint was calculated with the application of the most widely used limit state design codes Eurocode and AASHTO LRFD (2017). For the circumferential joints bursting design, an assumed TBM jack force was used with considering of the construction tolerance of the segments and the eccentricity of the jack's position. The analysis results show reinforcement is needed as joint bursting stresses exceeds the allowable tensile strength of concrete. This highlights that joint bursting check shall be considered as a mandatory design item in the limit state design of the segment lining.

Evaluation of steel fiber reinforcement effect in segment lining by full scale bending test (실물파괴실험에 의한 세그먼트 라이닝의 강섬유 보강 효과 평가)

  • Lee, Gyu-Phil;Bae, Gyu-Jin;Moon, Do-Young;Kang, Tae-Sung;Chang, Soo-Ho
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.15 no.3
    • /
    • pp.215-223
    • /
    • 2013
  • An experimental research on the possibility of using fiber reinforced concrete precast tunnel segments instead of traditional reinforced concrete(RC) segment has been performed in europe. This solution allows removing the traditional reinforcement with several advantages in terms of quality and cost reduction. Full-scale bending tests were carried out in order to compare the behaviour of the segments under flexural actions on both rebar reinforced concrete and rebar-fiber reinforced elements. The test results showed that the fiber reinforced concrete can substitute the traditional reinforcement; in particular the segment performance is improved by the fiber presence, mainly in terms of crack.