• 한국강구조학회 논문집
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• 제8권3호통권28호
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• pp.139-150
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• 1996

H/T(High Tension) bolt is generally being used in joining the members of steel structure. It has some difficulties in management such as an adequate fastening force and a selection of proper instrument for fastening. T/S(Torque Shear Type High Tension) bolt which is more convenient and easier than H/T bolt in quality control has recently been developed. T/S bolts are produced and widely used these days in domestic, but those have not a detail regulation for their on. Those are only being used according to the specification for the H/T bolts. In this study, we tried to confirm the soundness of T/S bolts by the fatigue test of the modified specimens. First, we measured the reduction rate of the initial axial force with time at bolts. Second, we investigated the slip forces of bolts when the test specimen is loaded in tension. Third, we implemented the fatigue tests. During the test, we measured the variation of the axial forces of bolts under the cyclic loading. Finally, we compared and analyzed the fatigue behavior of H/T and T/S bolt, by S-N curve diagrams that are obtained in this study.

• 한국산학기술학회논문지
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• 제16권12호
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• pp.8812-8819
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• 2015

콘크리트 궤도 건설의 증가로 인한 레일 체결장치의 중요성이 커지고 있는 상황에서 최근 레일 체결장치의 부속품인 텐션클램프가 절손되는 사고가 발생되었다. 이는 현장상태, 운영기관, 열차운행조건 및 빈도 등 다양한 요인에 의한 것으로 텐션클램프의 거동관련 연구가 필요하다. 본 논문에서는 실내실험 및 유한요소해석을 통해 텐션클램프의 역학적 거동을 분석하였다. 실내실험을 수행하여 텐션클램프 체결력에 따른 응력 및 변위를 도출하고 이를 유한요소해석 결과와의 비교를 통해 해석 모델을 검증하였다. 또한 검증된 모델을 적용하여 열차 하중에 따른 텐션클램프의 변형과 응력을 도출하고, 응력 분석을 통해 텐션클램프의 피로에 대한 취약도를 파악하였다.

• Structural Engineering and Mechanics
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• 제86권2호
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• pp.261-276
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• 2023

The use of the ordinary double nut (i.e., ODN) composed of a master nut (i.e., M-nut) and a slave nut (i.e., S-nut) is a highly efficient method to prevent bolts loosening. A novel double nut (i.e., FODN) composed of a master nut (i.e., M-nut) and flat slave nut (i.e., FS-nut) is proposed to save raw materials. The bolt fastening tests with single nut, ODN and FODN are performed to investigate the preload and counterbalance forces. Corresponding finite element analysis (FEA) models are established and validated by comparing the preload with the experimental results. The load-bearing capacity, the extrusion effect, and the contact stress of each engaged thread for ODN and FODN are observed by FEA. The experimental and simulated results revealed that the bolt fastening with double-nut has different load-transferring mechanisms from single-nut. Nevertheless, for double-nut/bolt assemblies, the FS-nut can provide load transfer that is like that of the S-nut, and the FODN is a reasonable and reliable fastening method. Furthermore, based on the theory of Yamamoto, a formula considering the extrusion effect is proposed to calculate the preload distribution of the double-nut, which is applicable to varying thicknesses of slave-nuts in double-nut/bolt assemblies.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.382-388
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• 2005

SMSC(Seoul Metropolitan Subway Corporation) is substantially taking the core role of mass transit system in Seoul Metropolitan area. When it was built, the design had challenged to sharp curved tracks less than 250m radius considering the protection of buildings and cultural properties as well as the connection to ground roads. Such circumstances have required a certain extent of slack in track geometry and therefore led to the construction of ballasted track with wooden sleepers. However, the dynamic force from running on sharp curved track has caused the misalignment and abnormal failure of track geometry, and it has resulted in a frequent maintenance and repair works which require a lot of cost and manpower. In this paper, we present the construction case of maintenance-free track system by using of concrete sleeper and elastic rail fastening system to ensure the safety of both passengers and trains, and to contribute the effective maintenance for track facilities of SMSC.

• 한국정밀공학회지
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• 제32권6호
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• pp.503-507
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• 2015

In this study, we compare the performance of the screw through the Clamping force of the test materials to change shape and structure, one of the ways to maintain and improve the engaging force to cope with the miniaturization of the fastener threads are further thinner and lighter precision way that can improve the fastening force of the screw results were as follows. The clamping force according to the materials was $7.57N{\cdot}cm$ in SUS XM7 and SWCH18A was $5.97N{\cdot}cm$. This result was to be found to average 13.5% high in the Clamping force of SUS XM7 materials. In the case of the clamping force of the screw thread shape change, the clamping force of symmetrical and asymmetrical thread was $6.78N{\cdot}cm$ and $7.57N{\cdot}cm$. The clamping force of the asymmetrical thread showed an average high of 11.6%.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.117-124
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• 2008

Construction of concrete slab track is trending to increase gradually in national and international for reduction in track maintenance cost and secure of ride comfort. However, in case of railway bridge installed concrete slab track, the serviceability review of end deck should be performed for reducing the maintenance cost of track. The serviceability review of track contains that the compression force which is occurred on fastener of end bridge should be smaller than the compression force causing the deformation limit of elastic pad and the uplift force which is occurred on fastener of end abutment should be smaller than initial fastening force. Therefore, this study calculated the deflection and end rotation of the railway bridge according to the span length and stiffness of railway bridge and estimated the compression force and uplift force which are occurred on the track of end bridge using the finite element method. This study indicated the several diagrams that are contained the correlation between the behaviour of the track and the behaviour of the railway bridge. As a result, to reduce the end rotation of the railway bridge is very efficient to increase the height of railway deck.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 사면안정 학술발표회
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• pp.3-38
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• 2000

Slope draperies in soil and rock are a well known method to avoid rockfalls into the roads or onto housings. Common wire mesh or a combination of wire mesh and wire rope nets are pinned to the slope by the means of fully grouted nails or anchors. Most of these installations have not been designed to stabilize the slope, but simply avoid the rocks from bouncing. The combination of soil- or rocknailing with a designable flexible facing system offers the advantage of a longterm stabilization of slopes and can replace other standard methods for slope stabilization. The capability to transfer axial and shear loads from the flexible facing system to the anchor points is most decisive for the design of the stabilization system. But the transfer of forces by mesh as pure surface protection devices is limited on account of their tensile strength and above all also by the possible force transmission to the anchoring points. Strong wire rope nets increase the performance for slope stabilizations with greater distances between nails and anchors and are widely used in Europe. However, they are comparatively expensive in relation to the protected surface. Today, special processes enable the production of diagonally structured mesh from high-tensile steel wire. These mesh provide tensile strengths comparable to wire rope nets. The interaction of mesh and fastening to nail / anchor has been investigated in comprehensive laboratory tests. This also in an effort to find a suitable fastening plates which allows an optimal utilization of the strength of the mesh in tangential (slope-parallel) as well as in vertical direction (perpendicular to the slope). The trials also confirmed that these new mesh, in combination with suitable plates, enable substantial pretensioning of the system. Such pretensioning increases the efficiency of the protection system. This restricts deformations in the surface section of critical slopes which might otherwise cause slides and movements as a result of dilatation. Suitable dimensioning models permit to correctly dimension such systems. The new mesh with the adapted fastening elements have already been installed in first pilot projects in Switzerland and Germany and provide useful information on handling and effects.

• 한국산학기술학회논문지
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• 제16권11호
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• pp.7870-7877
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• 2015

장대레일 궤도가 철도교량 상에 위치하는 경우, 교량과 궤도의 상호작용에 의해 레일에 발생하는 축력분포가 복잡해지며 부가축력이 발생하여 토노반상 장대레일에 비해 큰 축력이 레일에 발생된다. 이로 인해 교량상에 부설되는 궤도는 교량과의 상호작용 영향을 최소화하여 궤도와 주행열차의 안전성을 추가로 확보하여야 한다. 국내 철도설계지침 및 편람 KRC-08080(궤도-교량 종방향 상호작용 해석)에서는 상호작용의 주요 변수인 레일체결장치의 종방향 저항(마찰거동) 물성치가 유럽기준을 적용하여 특정 수치로 규정되어 있으나, 국내 철도에 적용하기 위해서는 실제 사용되는 체결장치의 성능 특성을 반영한 검토가 필요하다. 본 논문에서는 국내 교량상 콘크리트 궤도에 적용되는 레일체결장치의 마찰거동 실험을 수행하였으며, 이로부터 체결장치의 물성치에 대한 통계적 특성을 분석하였다.

• 한국철도학회논문집
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• 제16권3호
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• pp.217-225
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• 2013

본 연구에서는 교량 단부의 레일지지점 간격, 교량과 교대사이 거리(유간) 및 교량 단부 회전각을 고려하여 콘크리트 궤도가 부설된 교량 단부 궤도의 거동을 분석하였다. 궤도구조가 고려된 교량 및 교대 시험체를 이용한 실내시험 결과, 동일한 유간(레일지지점 간격)에서 교량 단부 회전각이 증가함에 따라 레일의 변위가 선형적으로 비례하는 것으로 나타났다. 또한 이러한 레일의 변위는 레일 및 체결구의 발생응력에 직접적인 영향을 미치는 것으로 분석되었다. 실험결과를 바탕으로 다중 회귀분석을 수행하여 레일지지점 간격 및 교량의 단부 회전각을 매개변수로 하는 철도교량 단부 궤도의 궤도-교량 상호작용력 예측식을 도출하였다.

• 한국도시철도학회논문집
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• 제6권4호
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• pp.383-392
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• 2018

본 연구에서는 비교적 경간이 긴 트러스교를 포함한 무도상 교량을 대상으로 장대레일을 부설할 때 궤도-교량 상호작용으로 인한 레일 부가 축응력과 교량 지점 반력 등의 변화를 검토하여 레일 장대화를 위한 개량 방안을 분석하였다. 연구결과에 따르면 무도상 교량에서 장대레일을 부설할 경우 레일 부가 축응력과 지점 반력이 큰 폭으로 증가하는 것으로 나타났다. 레일 부가 축응력은 횡저항력을 충분히 확보할 경우 수용 가능하지만, 지점 반력이 증가하게 될 경우 받침이나 교각의 손상이 우려되고 대규모 보수 보강을 필요로 하므로 지점 반력을 완화시킬 수 있는 방안을 강구할 필요가 있다. 교량 가동단의 마찰저항을 고려하는 경우 레일 부가 축응력은 감소하지만 지점 반력에 미치는 영향은 매우 작은 것으로 나타났다. 반면 궤도 종저항력이 작아지면 레일 부가 축응력과 지점 반력이 모두 큰 폭으로 감소하는 것으로 나타났으며, 레일 부가 축응력이 큰 일부 구간에 ZLR 체결장치를 적용하는 경우 레일 부가 축응력 뿐 아니라 교량 지점 반력이 크게 감소하는 것으로 나타났다. 따라서 무도상 교량의 레일 장대화를 위하여 일부 ZLR 체결장치를 적용하고 궤도 종저항력을 줄이는 방안이 매우 효과적이라고 판단된다.