• Title, Summary, Keyword: precast composites

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Influence of shear bolt connections on modular precast steel-concrete composites for track support structures

  • Mirza, Olivia;Kaewunruen, Sakdirat
    • Steel and Composite Structures
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    • v.27 no.5
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    • pp.647-659
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    • 2018
  • Through extensive research, there exist a new type of connection between railway bridge girders and steel-concrete composite panels. In addition to conventional shear connectors, newly developed blind bolts have been recently adopted for retrofitting. However, the body of knowledge on their influence and application to railway structures has not been thoroughly investigated. This study has thus placed a particular emphasis on the application of blind bolts on the Sydney Harbour Bridge as a feasible alternative constituent of railway track upgrading. Finite element modeling has been used to simulate the behaviours of the precast steel-concrete panels with common types of bolt connection using commercially available package, ABAQUS. The steel-concrete composite track slabs have been designed in accordance with Australian Standards AS5100. These precast steel-concrete panels are then numerically retrofitted by three types of most practical bold connections: head studded shear connector, Ajax blind bolt and Lindapter hollow bolt. The influences of bolt connections on load and stress transfers and structural behaviour of the composite track slabs are highlighted in this paper. The numerical results exhibit that all three bolts can distribute stresses effectively and can be installed on the bridge girder. However, it is also found that Lindapter hollow bolts are superior in minimising structural responses of the composite track slabs to train loading.

An Experimental Study on the Fire Resistance and Mechanical Properties of ECC Permanent Form (ECC 영구거푸집의 내화성능 및 역학적 특성에 관한 실험적 연구)

  • Kim, Yong-Ro;Song, Young-Chan;Oh, Jae-Keun;Kim, Jae-Hwan;Kim, Ook-Jong;Lee, Do-Bum
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.75-78
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    • 2009
  • It was investigated fire resistance properties and mechanical properties of high strength concrete column using ECC(Engineered Cementitious Composites) permanent form by KS F 2257 Methods of fire resistance test for elements of building construction and compression test for application of precast concrete column method of high rise building in this study. As a test result, it was appeared that ECC permanent form is available as fire resistance method of high strength concrete and new precast concrete construction method for facilitating construction of high rise building.

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Experimental Study on the Mechanical Properties of CF Reinforced Fly Ash-Cement Composites(I) (탄소섬유 보강 플라이 애쉬-시멘트 복합재의 역학적 특성에 관한 실험적 연구(I))

  • 박승범;윤의식;송용순
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.11-15
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    • 1990
  • Results of an experimental study on the manufacture and the mechanical properties of carbon fiber reinforced fly ash-cement composites are presented in this paper. The carbon fiber reinforced fly ash-cement composites using silica powder and a small amount of Ethylene vinyl acetate emulsion are prepared with carbon fiber, foaming agents and curing conditions. As a result, the manufacturing process technology of carbon fiber reinforced fly ash-cement composites is developed. And the mechanical properties such as compressive, tensile and flexural strengths and drying shrinkage of lightweight carbon fiber reinforced fly ash-cement composites are improved by using a small amount of Ethylene vinyle acetate emulsion. The development and applications of precast products and the design systems of lightweight carbon fiber reinforced fly ash-cement composites are expected in the near future.

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Design and modelling of pre-cast steel-concrete composites for resilient railway track slabs

  • Mirza, Olivia;Kaewunruen, Sakdirat;Kwok, Kenny;Griffin, Dane W.P.
    • Steel and Composite Structures
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    • v.22 no.3
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    • pp.537-565
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    • 2016
  • Australian railway networks possess a large amount of aging timber components and need to replace them in excess of 280 thousands $m^3$ per year. The relatively high turnover of timber sleepers (crossties in a plain track), bearers (skeleton ties in a turnout), and transoms (bridge cross beams) is responsible for producing greenhouse gas emissions 6 times greater than an equivalent reinforced concrete counterparts. This paper presents an innovative solution for the replacement of aging timber transoms installed on existing railway bridges along with the incorporation of a continuous walkway platform, which is proven to provide environmental, safety and financial benefits. Recent developments for alternative composite materials to replace timber components in railway infrastructure construction and maintenance demonstrate some compatibility issues with track stiffness as well as structural and geometrical track systems. Structural concrete are generally used for new railway bridges where the comparatively thicker and heavier fixed slab track systems can be accommodated. This study firstly demonstrates a novel and resilient alterative by incorporating steel-concrete composite slab theory and combines the capabilities of being precast and modulated, in order to reduce the depth, weight and required installation time relative to conventional concrete direct-fixation track slab systems. Clear benefits of the new steel-concrete composites are the maintainability and constructability, especially for existing railway bridges (or brown fields). Critical considerations in the design and finite element modelling for performance benchmarking of composite structures and their failure modes are highlighted in this paper, altogether with risks, compatibilities and compliances.

Seismic behavior of fiber reinforced cementitious composites coupling beams with conventional reinforcement

  • Liang, Xingwen;Xing, Pengtao
    • Earthquakes and Structures
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    • v.14 no.3
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    • pp.261-271
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    • 2018
  • Fiber reinforced cementitious composites (FRCC) materials that exhibit strain-hardening and multiple cracking properties under tension were recently developed as innovative building materials for construction. This study aims at exploring the use of FRCC on the seismic performance of coupling beams with conventional reinforcement. Experimental tests were conducted on seven FRCC precast coupling beams with small span-to-depth ratios and one ordinary concrete coupling beam for comparison. The crack and failure modes of the specimens under the low cycle reversed loading were observed, and the hysteretic characteristics, deformation capacity, energy dissipation capacity and stiffness degradation were also investigated. The results show that the FRCC coupling beams have good ductility and energy dissipation capacities compared with the ordinary concrete coupling beam. As the confinement stirrups and span-to-depth ratio increase, the deformation capacity and energy dissipation capacity of coupling beams can be improved significantly. Finally, based on the experimental analysis and shear mechanism, a formula for the shear capacity of the coupling beams with small span-to-depth ratios was also presented, and the calculated results agreed well with the experimental results.

Experimental Study on the Development and Application of High-Performance Composite Utilizing Industrial Wasts Products for Construction Works -Carbon Fiber Reinforced Fly Ash.Cement Composites- (산업폐기물을 이용한 건재용 고성능복합체의 개발 및 응용에 관한 실험적 연구 -탄소섬유 보강 플라이애쉬.시멘트 복합체-)

  • 박승범;이보성;윤의식
    • Magazine of the Korea Concrete Institute
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    • v.3 no.3
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    • pp.101-110
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    • 1991
  • Results of an experimental study on the manufacture, the mechanical properties and watertightness of pitch - based carbon fiber reinforced fly ash. cement composites are presented in this paper. The carbon fiber reinforced fly ash. cement composites using early strength cement silica powder and a small amount of stylene butadiene rubber latex are prepared with carbon fiber, foaming agents and mixing conditions. As a result, the mechanical and physical properties such as compressive , tensile and flexural strengths, watertightness and drying shrinkage of lightweight carbon fiber reinforced fly ash cement composites are Improved by using a samll amount of stylene butadiene rubber latex. Also, the manufacturing pnx:ess technology of carbon fiber reinforced fly ash . cement composItes is developed. The development and applications of precast products of lightweight carbon fiber remforced cement composites are expected in the near future.

Analytical Study on Hybrid Precast Concrete Beam-Column Connections (하이브리드 프리캐스트 보-기둥 접합부의 해석적 연구)

  • Choi, Chang-Sik;Kim, Seung-Hyun;Choi, Yun-Cheul;Choi, Hyun-Ki
    • Journal of the Korea Concrete Institute
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    • v.25 no.6
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    • pp.631-639
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    • 2013
  • Non-linear finite element analysis for newly developed precast concrete details for beam-to-column connection which can be used in moderate seismic region was carried out in this study. Developed precast system is based on composite structure and which have steel tube in column and steel plate in beam. Improving cracking strength of joint under reversed cyclic loading, joint area was casted with ECC (Engineering Cementitious Composites). Since this newly developed precast system have complex sectional properties and newly developed material, new analysis method should be developed. Using embedded elements and models of non-linear finite element analysis program ABAQUS previously tested specimens were successfully analyzed. Analysis results show comparatively accurate and conservative prediction. Using finite element model, effect of axial load magnitude and flexural strength ratio were investigated. Developed connection have optimized performance under axial load of 10~20% of compressive strength of column. Plastic hinge was successfully developed with flexural strength ratio greater than 1.2.

Flexural Behavior of Highly Ductile Cement Composites Mimicking Boundary Conditions of Shellfish Skin Layer (패류 껍질층의 경계면을 모방한 고연성 시멘트 복합재료의 휨 거동)

  • Kwon, Ki-Seong;Chun, Jae-Yeong;Bang, Jin-Wook;Kim, Yun-Yong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.1
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    • pp.108-115
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    • 2020
  • In this study, the flexural performance of Highly Ductile Cement Composites(HDCC) mimicking boundary conditions of shellfish skin layer was evaluated. To improve ductility by mimicking the boundary skin layer structure of shellfish, the method of stratification by charging between precast panels using HDCC and the method of distributing PE-mesh to the interface surface were applied. Evaluation of flexural performance of layered cement composite materials mimicking boundary conditions of shellfish skin layer resulted in increased ductility of all test specimens applied with stratified cross-section compared to typical bending test specimens. The layered method by inserting PE-mesh showed excellent ductility. This is most likely because the inserted PE-mesh made an interface for separating the layers while the HDCC pillars in the PE-mesh gave adhesion between layers.

Evaluation of Shear Performance on Two Sides Confined SHCC Infill Walls after Cross-Sectional Shape Modification (2면 구속한 SHCC 끼움벽의 단면 감소에 따른 전단성능 평가)

  • Cha, Jun-Ho;Nam, Sang-Hyun;Kim, Sun-Woo;Lee, Young-Oh;Yun, Hyun-Do
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.55-56
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    • 2010
  • Infill walls have been investigated experimentally and theoretically by many researchers during last decades. The objective of this research is to evaluate structural strengthening performance of lightly reinforced concrete with reduced the inside cross-section of Strain-hardening cement composites(SHCC) experimentally.

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