• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1264-1269
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• 2006

Measurement and estimation of rail irregularity is an important factor to concern travelling safety of train. Now a day, rail irregularity have been measured by EM120 and ROGER 1000K imported from MERMAC Co. Italy and making researches actively in Korea. This paper mainly consider to find correlation between acceleration value of wheel axle in HSR350x and rail irregularity value measured by EM120.

• 문화기술의 융합
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• 제9권4호
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• pp.633-638
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• 2023

본 연구에서는 공용중인 강철도 복합교량의 케이블 장력변화가 철도교량 상 자갈궤도의 궤도틀림에 미치는 영향을 해석적으로 분석하였다. 케이블 장력에 대한 설계 및 해석결과 비교 결과, 약 3% 미만의 차이가 나타나 해석모델링은 설계조건을 잘 반영하는 것으로 분석되었다. 또한 현장측정결과와 해석 케이블 장력과 비교하여 해석모델링의 적정성을 입증하였다. 케이블 장력 변화를 변수로 설정하여 강철도 복합교량의 궤도틀림을 해석적으로 분석하였다. 분석결과, 전체 및 편측 케이블 장력변화는 궤도틀림 항목 중 고저틀림에 직접적인 영향을 미치는 것으로 분석되었다. 또한 케이블 위치와 근접한 구간에서 궤도틀림의 변화가 발생하는 것으로 나타났다. 케이블 장력 변화는 수평방향에 의한 궤도틀림(방향틀림 및 궤간틀림)보다는 연직방향과 직접적인 상관성을 갖는 궤도틀림(고저틀림 및 수평틀림)에 보다 직접적인 영향을 미치는 것으로 분석되었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.311-319
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• 2011

Track accompanies the process that track alignment by traffic loads is changed. A change of track alignment affects the running safety and riding comfort of train. This is called a track irregularity. The most important task in maintaining the track is to manage these track irregularity within quality parameters. Today, track maintenance of urban transit is enforcing immediate maintenance about section exceeding a safety standard by applying track recording data got through Integrated Measurement. This method is advantage of being easy of the maintenance assesment in case of the running safety, but is disadvantage of being difficult in case of the riding comfort of train. In this study, we propose track irregularity deviation of each track system depending on the time series and present about utilization plans of the Track Irregularity Progress Rate.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.766-771
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• 2008

In this paper, the vibration of high speed trains and the irregularity of railway are examined using a wavelet-based frequency response function. To investigate their characteristics, non-stationary acceleration data are acquired and processed using the wavelet transform. Also, the railway irregularity is examined by acquiring the data from the on-board laser-based measurement system. The correlation between the train vibration and the railway irregularity has been investigated. From the analysis, the wavelet-based frequency response function is a promised method for the dynamic characteristics of high speed trains.

• Earthquakes and Structures
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• 제12권4호
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• pp.437-448
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• 2017

Soft or extreme soft storeys in multi-storied buildings cause localized damage (and even collapse) during strong earthquake shaking. The presence of such soft or extremely soft storey is identified through provisions of vertical stiffness irregularity in seismic design codes. Identification of the irregularity in a building requires estimation of lateral translational stiffness of each storey. Estimation of lateral translational stiffness can be an arduous task. A simple procedure is presented to estimate storey stiffness using only properties of fundamental lateral translational mode of oscillation (namely natural period and associated mode shape), which are readily available to designers at the end of analysis stage. In addition, simplified analytical expressions are provided towards identifying stiffness irregularity. Results of linear elastic time-history analyses indicate that the proposed procedure captures the irregularity in storey stiffness in both low- and mid-rise buildings.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1090-1095
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• 2008

Track geometry changes by traffic loads. The bigger the changes are, the worse the riding comfort and running stability of train. This is so-called track irregularity and is the most important quality parameters of ballasted track. To objectively assess track irregularity, track geometry should be able to be measured. Practically, railway companies use moving chord method, which determine versine values via a chord. The versine is the vertical distance to curve measured in the middle of the chord. This type of method measures only versine of track irregularity curve by transfer function from the characteristics of measuring device. In this report, review the characteristics of two types of measuring tools by comparing the measurements. The one is GRP-1000 system, optical surveying system with Total station and lazar prism trolley. This calculates track geometry by surveying absolute coordinates of two points each on both rail heads. The other is EM-120, measures versine with 10m of symmetrical chord length.

• 대한건축학회논문집:구조계
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• 제35권10호
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• pp.191-198
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• 2019

In this paper the evaluation scheme for determining torsional irregularity of Hanok has been proposed. The proposed method can evaluate torsional irregularity of Hanok easily only with characteristics of Hanok shapes, arrangement of lateral load resisting frames and their lateral stiffness without time consuming and complicate 3-dimensional structural analysis. The proposed formula is expressed as allowable maximum eccentricity, and torsional irregularity is evaluated by comparing this value with actual eccentricity. The applicability of the proposed scheme was evaluated by applying it to the line shape plan Hanok with two symmetrically arranged walls and the result was expressed by formula and graph. The results showed that the allowable maximum eccentricity is 10% of plan dimension perpendicular to the seismic load when the walls are placed at the extreme end. The proposed formula was expressed as a generalized formula so it can be applied generally to the various plan shape and wall arrangement of Hanok.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2405-2408
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• 2011

In recent time, the cause analysis and the reduction of the track irregularity have become the most important issue in the ballasted track on the high-speed railway bridge. This is because that the frequency of the maintenance work at the bridge expansion joint zone is on the rise. The track irregularity on the railway bridge starts at the end of the bridge-deck and spreads along the bridge. Due to the dynamic vibration and the thermal expansion of the bridge, the compaction of the ballast gravel on the bridge expansion joint zone become loose and then the progress of the track irregularity result from the train-induced dynamic impact is accelerating further. Among the several options for reducing the track irregularity on the bridge expansion joint zone, the application and efficiency of the zero longitudinal restraint(ZLR) and tied sleeper are investigated in this paper. Field test construction has been conducted, then the progress of the track irregularity and the frequency of the maintenance work are analyzed before and after the filed test construction. Of the two methods, it is shown that the installation of the ZLR seems to be better than the tied sleeper.

• 전기학회논문지
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• 제63권12호
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• pp.1690-1696
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• 2014

Network RTK generates spatial corrections by using differenced measurements from reference stations in the network, and the corrections are then provided to a rover. The rover, generally, uses linear interpolation, which assumes that the corrections at each reference station are spatially correlated, to obtain a precise correction of its location. However, an irregularity of the tropospheric delay is a real-world factor that violates this assumption. Tropospheric delay is a result of weather conditions, such as humidity, temperature and pressure, and it can cause spatial decorrelation when there are changes in the local climate. In this paper, we have defined the non-linear characteristics of the tropospheric delay between reference stations or user within a region as the "irregularity of tropospheric delay". Such an irregularity can negatively impact the network RTK performance. Therefore, we analyze the influence of the irregularity of tropospheric delay in network RTK based on meteorological data.

• Steel and Composite Structures
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• 제46권1호
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• pp.93-105
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• 2023

This paper examines a high-speed railway CRTS-II ballastless track-bridge system. Using the stationary potential energy theory, the mapping analytical solution between the bridge deformation and the rail vertical geometric irregularity was derived. A theoretical model (TM) considering the nonlinear stiffness of interlayer components was also proposed. By comparing with finite element model results and the measured field data, the accuracy of the TM was verified. Based on the TM, the effect of bridge deformation amplitude, girder end cantilever length, and interlayer nonlinear stiffness (fastener, cement asphalt mortar layer (CA mortar layer), extruded sheet, etc.) on the rail vertical geometric irregularity were analyzed. Results show that the rail vertical deformation extremum increases with increasing bridge deformation amplitude. The girder end cantilever length has a certain influence on the rail vertical geometric irregularity. The fastener and CA mortar layer have basically the same influence on the rail deformation amplitude. The extruded sheet and shear groove influence the rail geometric irregularity significantly, and the influence is basically the same. The influence of the shear rebar and lateral block on the rail vertical geometric irregularity could be negligible.