• 대한토목학회논문집
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• 제42권6호
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• pp.751-762
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• 2022

강합성 교량에서 강 거더와 콘크리트 바닥판의 합성을 위한 전단연결재로는 용접접합 머리붙이 스터드가 주로 사용된다. 용접접합 전단연결재의 경우, 손상 또는 노후화된 바닥판 철거 시에 파쇄에 따른 소음, 비산먼지 등이 발생하여 환경적 문제가 지적되고 있다. 따라서 환경적 문제 및 생애주기비용 관점의 효율적인 유지관리를 위해서는 노후화된 콘크리트 바닥판의 교체가 용이한 분리식 전단연결재 개발이 필요하다. 기존의 볼트접합 전단연결재로는 매립너트 방식이 주로 연구되었으나 낮은 강성과 전단저항강도, 초기슬립 증가 등으로 교량과 같은 토목구조물에는 활용되지 못하고 있는 실정이다. 본 논문에서는 이러한 문제점들을 개선하기 위해 매립너트 부분이 스터드 기둥에 일체화되고 확대 기둥 하단에 테이퍼진 형상을 갖는 분리식 볼트접합 전단연결재를 제안하였다. 제안된 분리식 스터드볼트의 정적 전단강도와 슬립 변위에 대한 성능 검증을 위해 수평전단실험을 수행하였고, 기존 용접접합 스터드와 성능을 비교하였다. 제안된 분리식 볼트접합 전단연결재가 전단성능이 매우 우수하고, 슬립변위 또한 연성설계기준을 만족함으로써 기존 용접 스터드를 충분히 대체하여 적용 가능함을 확인하였다.

• 한국산학기술학회논문지
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• 제10권1호
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• pp.165-170
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• 2009

본 논문은 GFRP-데크와 콘크리트를 합성한 1방향 슬래브 시스템을 제안하고자 기존의 철근트러스-데크 합성슬래브와의 비교실험을 통하여 휨성능에 대한 구조실험을 수행하였다. 실험결과 휨성능은 제안된 GFRP 합성슬래브의 시험체들이 비교시험체들 보다 우수하게 나타나, 재료의 적절한 품질관리가 이루어진다면 GFRP가 갖고 있는 내부식성의 장점을 살릴 수 있는 배기가스나 염분에 많이 노출된 건축물에 매우 효과적으로 적용할 수 있을 것으로 판단된다.

• 한국산업융합학회 논문집
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• 제9권3호
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• pp.215-220
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• 2006

Recently, steel-concrete composite slab decks have been widely used as highway bridge decks. In the construction of the composite slab decks, it is necessary to join two adjacent blocked bottom plates to form one unite in the longitudinal direction. In this paper, several types of longitudinal direction joints for Robinson type composite slab decks ared proposed herein and static bending test are carried out by using slab specimens. And the stress and deformation of the tensile grip connection with high strength bolts are discussed by using three-dimensional elastic-plastic FEM.

• Steel and Composite Structures
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• 제45권6호
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• pp.895-905
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• 2022

Composite flooring systems consisting of cold-formed steel joists and reinforced concrete slabs offer an efficient, lightweight solution. However, utilisation of composite action to achieve enhanced strength and economical design has been limited. In this study, finite element modelling was utilised to create a three-dimensional model which was then validated against experimental results for a composite flooring system consisting of cold-formed steel joists, reinforced concrete slab and steel bolt shear connectors. This validated numerical model was then utilised to perform parametric studies on the performance of the structural system. The results from the parametric study demonstrate that increased thickness of the concrete slab and increased thickness of the cold formed steel beam resulted in higher moment capacity and stiffness of the composite flooring system. In addition, reducing the spacing of bolts and spacing of the cold formed steel beams both resulted in enhanced load capacity of the composite system. Increasing the concrete grade was also found to increase the moment capacity of the composite flooring system. Overall, the results show that an efficient, lightweight composite flooring system can be achieved and optimised by selecting suitable concrete slab thickness, cold formed beam thickness, bolt spacing, cold formed beam spacing and concrete grade.

• 한국강구조학회 논문집
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• 제21권6호
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• pp.637-646
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• 2009

바닥슬래브가 있는 경우 국내에서 설계되는 트러스보는 바닥 슬래브와의 합성효과를 고려하지 않고 있다. 이 연구에서는 상하현재를 H형강으로 구성한 합성트러스를 사용하여 기본적인 실험을 수행하였다. 실험에서는 합성트러스의 역학적 거동을 조사하기 위하여 전단연결재의 유무에 따른 영향을 검토하였다. 실험체로서는 철골트러스, 비합성 및 합성트러스 등으로 이루어지며 가력방법으로는 중앙집중재하와 균등휨의 두가지 방법을 사용하였다. 시어 커넥터를 사용한 합성트러스의 합성효과가 실험적으로 확인되어졌다.

• Steel and Composite Structures
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• 제34권6호
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• pp.837-851
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• 2020

This study aims to examine the interface shear behavior between precast high-strength concrete slabs with pockets and steel beam to achieve accelerated bridge construction (ABC). Twenty-six push-out specimens, with different stud height, stud diameter, stud arrangement, deck thickness, the infilling concrete strength in shear pocket (different types of concrete), steel fiber volume of the infilling concrete in shear pocket concrete and casting method, were tested in this investigation. Based on the experimental results, this study suggests that the larger stud diameter and higher strength concrete promoted the shear capacity and stiffness but with the losing of ductility. The addition of steel fiber in pocket concrete would promote the ductility effectively, but without apparent improvement of bearing capacity or even declining the initial stiffness of specimens. It can also be confirmed that the precast steel-concrete composite structure can be adopted in practice engineering, with an acceptable ductility (6.74 mm) and minor decline of stiffness (4.93%) and shear capacity (0.98%). Due to the inapplicability of current design provision, a more accurate model was proposed, which can be used for predicting the interface shear capacity well for specimens with wide ranges of the stud diameters (from13 mm to 30 mm) and the concrete strength (from 26 MPa to 200 MPa).

• Steel and Composite Structures
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• 제29권6호
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• pp.735-748
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• 2018

In this paper, the cyclic behavior of steel beam-concrete encased steel (CES) column joints was investigated experimentally and numerically. Three frame middle joint samples with varying concrete slab widths were constructed. Anti-symmetrical low-frequency cyclic load was applied at two beam ends to simulate the earthquake action. The failure modes, hysteretic behavior, ultimate load, stiffness degradation, load carrying capacity degradation, displacement ductility and strain response were investigated in details. The three composite joints exhibited excellent seismic performance in experimental tests, showing high load-carrying capacity, good ductility and superior energy dissipation ability. All three joint samples reached their ultimate loads due to shear failure. Numerical results from ABAQUS modelling agreed well with the test results. Finally, the effect of the concrete slab on ultimate load was analyzed through a parametric study on concrete strength, slab thickness, as well as slab width. Numerical simulation showed that slab width and thickness played an important role in the load-carrying capacity of such joints. As a comparison, the influence of concrete grade was not significant.

• Steel and Composite Structures
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• 제22권3호
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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.

• Steel and Composite Structures
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• 제9권6호
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• pp.569-584
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• 2009

Corrosion of steel rebars in bridge decks which are faced to harsh conditions, is a common problem in construction industries due to the porosity of concrete. In this research, the behavior of one-way concrete slabs reinforced with Glass fiber reinforced polymer (GFRP) molded grating is investigated both theoretically and experimentally. In the analytical method, a closed-form solution for load-deflection behavior of a slab under four-point bending condition is developed by considering a concrete slab as an orthotropic plate and defining stiffness coefficients in principal directions. The available formulation for concrete reinforced with steel is expanded for concrete reinforced with GFRP molded grating to predict ultimate failure load. In finite element modeling, an exact nonlinear behavior of concrete along with a 3-D failure criterion for cracking and crushing are considered in order to estimate the ultimate failure load and the initial cracking load. Eight concrete slabs reinforced with steel and GFRP grating in various thicknesses are also tested to verify the results. The obtained results from the models and experiments are relatively satisfactory.

• 한국안전학회지
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• 제29권3호
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• pp.72-78
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• 2014

The minimum thickness of long-span deck slab is proposed by checking the limit state according to the Korean highway bridge design code(limit state design). Both minimizing thickness and ensuring safety of deck slab are important design factors to increase a competitive price of the long span deck slabs. The required thicknesses for satisfying flexural capacity, preventing punching shear failure and limiting deflection were calculated by considering KL-510 load model which has increased total load compared to DB 24 from 432 kN to 510 kN. The results of the required thickness for various limit states were compared to propose the minimum thickness as a function of span length of deck slabs. The proposed minimum thickness is influenced by satisfying flexural capacity and limiting deflection. It turns out to be similar compared to the results of the previous study by ultimate strength design method even if the live load model was increased in total weights.