• Proceedings of the KACD Conference
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• 2003.05a
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• pp.289-289
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• 2003

I. Objectives Narrow long oval canals usually cannot be instrumented completely and uninstrumented extensions or irregularities usually remain. The aim of this study was to compare the ability of syringe irrigation and ultrasound irrigation to remove dentin debris from simulations of uninstrumented canal extensions and irregularities.(omitted)

• Computers and Concrete
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• v.14 no.4
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• pp.405-417
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• 2014

The poor seismic performance of reinforced concrete buildings during the latest earthquakes has become a serious issue in the building industry in Turkey. This case, designing new buildings without structural irregularities against earthquake loads reveals to be quite significant. This study mainly is focused on the effects of different torsional irregularities on construction costs and earthquakes performance of reinforced concrete buildings. In that respect, structural torsional irregularities are investigated based on the Turkish Earthquake Code. The study consists of major eight main parametric models. In this models consist of totally 49 models together with the variations in the number of storey. With this purpose, the earthquake performances and construction costs (especially steel quantities) of reinforced concrete buildings which having different structural torsional irregularities were obtained with the help of Sta4-CAD program. Each model has been analyzed by both the methods of equivalent earthquake loading and dynamic analysis. The obtained results reveal that the model-1 which has lower torsional irregularity coefficient shows the best earthquake performance owing to its regular plan geometry. Also, economical comparisons on costs of the torsional irregularity are performed, and results-recommendations are given.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.208-215
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• 2001

The vertical irregularities occurred in the structure may lessen the overall seismic capacity of the structure. Seismic capacity evaluation guidelines (e.g. FEMA 175, ATC-14) propose the criterion for the vertical irregularities of mass, stiffness and strength respectively. But, the criterion seems groundless and leads us to make a true/false decision only. This study is to draw a reasonable basis on which multi-level grading is possible based fur the evaluation of existing buildings. Time history analysis for 3-,5-, and 10-story steel frame structures has been performed using several earthquake data. ANN (Artificial Neural Network) is introduced to find the relative contribution factor of the irregularities along the irregular position. Also, the application system fur the seismic capacity evaluation can be established using the trained ANN.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.426-433
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• 2000

The whole track system is designed and maintained to provide satisfactory geometry. Renewal and collection decisions are often governed by track irregularities. To provide cost-effective track to meet in the need in the future it is essential to be able to improve the methods by which the performance of the track is monitored and to have reliable methods for prediction and planning. This paper develops computer-aided system for analysis and management of track irregularities. The main objective is to collect and monitor track irregularities for each conventional line to be used as an aid in making decisions on track correction and renewal. The final decision especially on track renewal, however, always be a decision made by man and not by computer-aided system.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.278-282
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• 2007

The riding comfort and the durability of train are effected by the rail irregularities such as track gauge, superelevation, alignment, longitudinal level, twist, cant and cross level. Inspection and estimation of irregularities are very important to maintain the rail condition. Generally, the EM120 has been utilized to measure the rail irregularities once a month in Korea. However, the EM120 can be operated at night time only, because the inspection speed of EM120 is much slower than the speed of high-speed trains. Also, the EM120 is too slow to inspect effectively for the whole commercial line. Therefore, we have mounted the track inspection system on the High-Speed Rolling Stock 350 eXperimental (HSR350X) and measured the rail irregularities to confirm the condition of a rail while running 300km/h. In this paper, the track inspection system mounted on HSR350X is mainly considered, and the measured results through test run are introduced.

• Structural Engineering and Mechanics
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• v.62 no.2
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• pp.179-196
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• 2017

The paper focuses on dynamic analyses of a series of simply-supported symmetric composite steel-concrete bridges loaded by an ICE-3 train moving at high speeds up to 300 km/h. The series includes five bridges with span lengths ranging from 15 m to 27 m, with repeatable geometry of the superstructures. The objects, designed according to Polish standards valid from 1980s to 2010, are modelled on the bridges serviced on the Central Main Line in Poland since 1980s. The advanced, two-dimensional, physically nonlinear model of the bridge-track structure-high-speed train system takes into account unilateral nonlinear wheel-rail contact according to Hertz's theory and random vertical track irregularities equal for both rails. The analyses are focused on the influence of random track irregularities on dynamic response of composite steel-concrete bridges loaded by an ICE-3 train. It has been pointed out that certain restrictions on the train speed and on vertical track irregularities should be imposed.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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• pp.92-101
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• 1997

In this paper, modeling methods for 2D joints are proposed. Earlier methods for modeling 2D joints that use geometric relationships may not consider irregularities or dynamic effects of joints. In any case, it is important to consider irregularities or dynamic effects. To consider those, methods that use dynamic contacts are proposed. With the method, 2D joints that have irregularities or dynamic effects amy be model- ed and analyzed. 2D joints that are developed are revolute, translational, gear and point-follower joint.

• Journal of the Korean Society for Railway
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• v.18 no.1
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• pp.63-70
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• 2015

Track irregularities have a strong influence on the safety and the ride comfort of trains as well as track maintenance work. A statistical analysis was conducted for track irregularities data measured in Kyoungbu high speed line using a track recording car(EM120). First, the characteristics of EM120, which adopted versine measurement system, were investigated and the transfer function of EM120 was examined. The distributions of the surface and the alignment which have short wavelength were considerably high and the distribution decreased as wavelength increases. A distribution analysis of the wavelength was carried out according to EN standards and most of the track irregularities were in a D1 wavelength range. The distributions of the amplitude of track irregularities were also investigated and the results show that the distributions of track irregularities decrease rapidly as amplitude increases. These results may be helpful in making track maintenance plans and revising track irregularities criteria.

• Proceedings of the Optical Society of Korea Conference
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• 2004.02a
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• pp.368-369
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• 2004

Birefringence due to structural irregularities in photonic crystal fiber is numerically analyzed. The statistical correlations between the birefringence and the degree of the irregularities are presented, and their behaviors are explained using a perturbation theory.

• Structural Engineering and Mechanics
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• v.47 no.6
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• pp.791-818
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• 2013

The seismic performance of reinforced concrete (RC) frame structures with irregularities leading to soft first floor is studied using capacity assessment procedures. The soft first story effect is investigated for the cases: (i) slab-column connections without beams at the first floor, (ii) tall first story height and (iii) pilotis type building (open ground story). The effects of the first floor irregularity on the RC frame structure performance stages at global and local level (limit states) are investigated. Assessment based on the Capacity Spectrum Method (ATC-40) and on the Coefficient Method (FEMA 356) is also examined. Results in terms of failure modes, capacity curves, interstory drifts, ductility requirements and infills behaviour are presented. From the results it can be deduced that the global capacity of the structures is decreased due to the considered first floor morphology irregularities in comparison to the capacities of the regular structure. An increase of the demands for interstory drift is observed at the first floor level due to the considered irregularities while the open ground floor structure (pilotis type) led to even higher values of interstory drift demands at the first story. In the cases of tall first story and slab-column connections without beams soft-story mechanisms have also been observed at the first floor. Rotational criteria (EC8-part3) showed that the structure with slab-column connections without beams exhibited the most critical response.