Earticle

교량의 내하력평가는 유지관리에 있어서 매우 중요한 요소이다. 재하시험과 구조해석에 의한 처짐이 차이를 보이는 이유는 여러 가지가 있다. 특히, 지점의 실제 거동특성을 고려하지 않고 일률적으로 모델링을 하는 경우에 이러한 문제가 더욱 심화될 수 있다. 이는 응력보정계수를 크게 산정하여 내하력을 실제보다 더 크게 평가할 우려가 있다. 본 연구에서는 지점의 거동특성을 고려하여 산정한 지점의 부모멘트를 이용하여 실제거동에 근접한 구조해석을 실시하야 보다 정확한 내하력을 평가하고자 한다.

Load carrying capacity evaluation is very important element in maintenance of bridge. There are several reasons about differences in deflection caused by loading test and structural analysis. Especially when we do modeling uniformly without considering real structural characteristics of support, this problem can be more deepened. This computes modification factor high so we may evaluate the load carrying capacity more than fact. In this study, we do structural analysis nearing real structure with negative bending moment of support that computes considering structural characteristics of support, and then evaluate load carrying capacity.

The centerless through-feed grinding is performed by passing the workpiece between the grinding wheel and the regulating wheel. So, the amount of removed material around the leading end, of the workpiece is always more than that around the trailing end until the leading end leaves the grinding wheel. Because of this, there are differences in diameters along the workpiece axis during grinding, and workpiece axis is not parallel to the grinding wheel axis and the contact lines between the workpiece and wheels. Thus the ground workpiece shows tapering error inherently. To eliminate this error, the workpiece axis must be kept to be parallel to the grinding wheel axis. And, the direction of the workpiece axis can be controlled by the work-rest blade. Therefore, the effects of work-rest blade inclination angle on the through-feed centerless ground part are investigated in this study. As a result, it is found that there is a positive inclination angle of the work-rest blade for minimizing the tapering error of a ground workpiece.

Bearings at the obtuse corner are subjected to much larger vertical reactions than other bearings because of the geometric shape of skew bridges. The current relevant specifications require that additional bars should be disposed at the bottom of concrete deck slabs to deal with the large vertical reaction on bearings at the obtuse corner. In this study, new methods of reducing the magnitude of the vertical reaction on bearings at the obtuse corner by the stiffness adjustment of bearings were proposed. The basic concept of proposed methods was to redistribute support reactions by reducing the vertical stiffness of bearings at the obtuse corner showing a relatively large vertical reaction. For 45 simply supported skew bridges designed according to the current relevant specifications, the redistribution effect of vertical reactions by the stiffness adjustment of bearings was investigated. Parameters such as skew angle, girder spacing, and deck aspect ratio that affect the distribution of support reactions were considered. The results of the analyses show that the magnitude of the vertical reaction on bearings at the obtuse corner can be reduced to the levels of straight bridges by replacing the existing bearings at the obtuse corner with new ones having the value of 1/10 or 1/20 of the vertical stiffness of the existing bearings. The reduction effect of the vertical reaction on bearings at the obtuse corner increases as the girder spacing decreases and it is more pronounced when the deck aspect ratio is 2.0.

There is a mechanical device between the superstructure and substructure of a bridge, which transmit vertical load of superstructure to the substructure and absorb horizontal displacement of super structure due to thermal, dynamic, load, etc. In order to meet two requirements at once, the structure of roller between plates is widely used, and this roller between plates is widely used, and this roller shoe system is known to have smaller horizontal movement resistance than any other type of bridge shoe. In this study, rolling friction resistance characteristics of roller-plate friction system is investigated according to roller dimension, vertical load, hardness and roughness of roller and plate. On the base of the results, the rolling friction resistance of large scale roller shoe is evaluated using model experiment.

적충되어 있는 다중 블록 시스템은 역사적 건물이나 문화재등에 자주 사용되고 있다. 이러한 구조시스템은 지진에 매우 취약하고, 특히 세장한 구조물인 경우에는 낮은 수준의 지반가속도에 대해서도 전도가 일어날 수 있다. 지진으로부터 이러한 구조물을 보호할 수 있는 방법중의 하나로써 지진격기받침의 사용을 들 수 있으나, 아직 격리받침이 설치되어 있는 다중블록의 거동에 대해서는 잘 알려지지 않는 실정이다. 이 논문에서는 각각 P-F 시스템, FPS, LRB 시스템이 설치되어 있을때의 세장한 강체 블록의 동적거동에 대해 살펴보았다. P-F 시스템과 FPS에서의 마찰모델은 Coulomb의 마찰법칙을 이용하였도, 상부구조물은 붙음(stick)모드와 록킹(rocking) 모드만이 존재하도록 가정하였다. 충격은 개별요소법(distinct element method, DEM)을 이용해 기술하였고, 조화입력운동에 대한 응답을 조사하였다.

The purpose of this study is to evaluate the dynamic behavior of highway bridge due to moving vehicle load, considering the effect of laminated rubber bearing. Dynamic behaviors of bridge considering the effect of bearings are studied with 3-dimensional bridge and vehicle models. To analyze the effect of bearings on the dynamic behaviors of superstructures of bridges, laminated rubber bearing is modeled as 3-dimensional frame element with equivalent stiffness and damping, and the models are included in the bridge analysis model. The results from the analytical models with laminated rubber bearing show a significant effects on dynamic responses and more complex vibration characteristics compared with the results from the bridge with pot bearings. Generally, larger dynamic amplification factors are obtained in the case of laminated rubber bearing, which is mainly due to the smaller torsional stiffness of the bridge with laminated rubber bearing. It can be recommended that were careful consideration on the vibration of bridges and dynamic load allowance in design are needed when adopting laminated rubber bearing.

Piled multi-block system has been frequently adopted in the historic structures or monuments of cultural heritage. It is well known that such a structural system is very vulnerable to the earthquake shaking. If the structure is of slender type, then it may experience overturning at very low level intensity of ground shaking. One of the methods used to protect such structures from earthquake is seismic isolation system. But the behavior of multi-block systems mounted on the isolated basis is not well understood yet. In this paper we investigate the dynamic behavior of single slender rigid block mounted on the three different isolation systems, i.e., P-F system, FPS and LRB system. Sliding at the isolation interface of P-F system and FPS is formulated based on Coulomb friction. The mounted single block is assumed undergoing rocking or sticking only. Impacting of a single block is described using distinct element method (DEM). Free vibrations due to a prescribed initial conditions are studied. Responses to the harmonic excitation and earthquake motions are calculated

Earthquake damage civil engineering structures every year in the world and bridges are no exception. Bridge structures have proven to be vulnerable to earthquake, sustaining damage to substructure and foundation and being totally destroys as superstructures collapse from their supporting elements. The poor seismic performance of bridge structures is surprising in view of the substantial advance made in design and construction for vertical load. Recently, bridge spans have been pushed further than before, alignment has become increasingly complex and aesthetic requirement have been become more demanding. To reduce the seismic force and to improve the safety of the advanced bridges, the bridge bearings which are the substructures and foundations and their connections to the superstructure become more important and critical elements. Therefore, the functions about seismic devices to be using as bridge bearing are discussed.

In this study, MIDAS Civil was used to perform nonlinear static analysis on bridge piers, followed by time-history analysis after applying seismic isolation devices. The results revealed that as the height of the piers increased, structural capacity and strength decreased, while the required capacity increased as the ground weakened. Additionally, lead-rubber bearings demonstrated superior performance compared to friction pendulum bearings in terms of displacement, shear force, and moment in both the bridge axis and pier directions. Furthermore, it was found that seismic waves have different impacts depending on the natural frequency of the structure, highlighting the need to consider various seismic waves during the design phase to ensure structural stability. The study also confirmed that seismic performance decreases with increasing pier height, emphasizing the necessity of reinforcement in the design.

이 논문은 서울 지역 화자와 대구 지역 화자를 대상으로 <표준발음법>에서 제시된 겹받침 발음 실태를 살펴보는 것이 목적이다. 언어 현실에서 겹받침 체 언은 모음으로 시작하는 형식 형태소와 결합할 때, 겹받침 용언은 자음으로 시 작하는 형태소와 결합할 때 각기 두 유형의 발음이 나타나는 것으로 관찰된다. 즉 겹받침 체언의 경우 단순 연음이 진행된 발음과 자음군 단순화가 선행된 뒤 연음된 발음이 공존하고 겹받침 용언은 자음으로 시작하는 형식 형태소가 뒤 따를 때 자음군 단순화가 일어나는데 ‘ㄹ’이 탈락한 발음과 ‘ㄹ’ 이외의 자음이 탈락한 발음이 함께 나타난다. 이 논문은 이러한 실태를 확인하고자 한다. 그리 고 두 지역에서 발생하는 발음 양상의 차이가 지역적 요인에 의한 것인지를 알 아보고자 한다. 이러한 결과를 종합하여 겹받침 체언이 모음으로 시작하는 형식 형태소와 결합할 때 서울 지역의 경우 단순 연음이 진행된 발음(표준발음)을 선호하지만 대구 지역은 자음군 단순화가 선행된 뒤 연음이 일어나는 발음(비표준발음)이 두드러지게 나타난다는 것을 밝힌다. 이와는 달리, 겹받침 용언의 경우 두 지 역 모두 표준발음에 대한 선호도는 차이가 없지만 자음군 단순화가 일어날 때 ‘ㄹ’ 이외의 자음이 탈락하는 발음을 선호한다는 것을 확인한다. 특히 대구 지 역에서 이 발음을 더욱 선호하고 있다는 것을 밝힌다.

The purpose of this paper is to investigate the actual pronunciation of the final cluster in standard Korean pronunciation by speakers in Seoul and Daegu. Empirically, it was observed that when a word with a final consonant cluster is affixed to a vowelinitial morpheme versus a consonant-initial morpheme, two pronunciations can be realized. That is, in the case of a consonantinitial suffix, the consonant cluster does not simplify but is resyllabified such that both consonants are pronounced, whereas in the case of a morpheme starting with a consonant, simplification of the cluster occurs. This study empirically tests these claims. The purpose of this study was to determine whether the differences in these patterns between the two regions were due to regional factors. In case of Seoul, simple pronunciation (the standard pronunciation) is preferred. However, in Daegu, non-standard pronunciations are prominent. However, in the case of suffixation, it is confirmed that the preference for the standard pronunciation is common in the two regions, but when the simplification of the consonant group occurs, the pronunciation of consonants other than 'd' is preferred, especially in Daegu.

The purpose of this study is analysis on pronunciation practice feature of consonant cluster incoda in Korean language. The result of pronunciation analysis by letting university students who were born and are currently residing in Seoul and Gyeonggi area to recite morphologically constituted ‘uninfleced word + postposition’, ‘verb stem final+ inflectional affix’ phrases with – consonant cluster incoda, is as follows;1. In morphologically constituted ‘uninflected word + postposition’Firstly, final double consonants are highly used in standard pronunciation as [ㅅ] located after consonant is popularly pronounced as [ㅆ], if ‘uninflected word’ having ‘ㄳ, ㅄ’ as final consonant is combined with postpositional particle starting with a vowel. Secondly, consonant cluster incoda ‘ㄺ, ㄻ, ㄼ, ㄽ’ were mostly pronounced as [ㄹ]. Especially in case of high more erroneous than standard pronunciation of ‘ㄺ, ㄼ, ㄽ’ pronounced from ‘chicken’, ‘eight’ and ‘single-minded’, this case may be regarded as reconstruction course into ㄹ. 2. In morphologically constituted ‘verb stem final+ inflectional affix’Firstly, verb stem final with ‘ㄵ, ㄻ, ㄾ’ were poor in vocabulary and frequently used, high weight of the university students were using standard pronunciation. Secondly, in case of consonant cluster incoda ‘ㅄ’, standard pronunciation is the popular case whereby [ㅅ] located after consonant is pronounced as tense sound, in identical case with ‘uninflected word + postposition’Thirdly, final double consonants ‘ㄺ, ㄼ’ was pronounced as [ㄹ] in the same way as the final double consonants combined with /ㄹ/ at ‘uninflected + postposition’. Especially high weight of the students were found as pronouncing as [ㄹ] even in exceptional composition of not pronounced as [ㄹ], the process of reconstruction to [ㄹ] appears in case of university students’ pronunciation of final double consonants combined with /ㄹ/ in Seoul and Gyeonggi regions. Fourth, final double consonants ‘ㄿ’ was highly pronounced as /ㄹ/ rather than the standard pronunciation, in the same way as the case of final double consonants combined with [ㄹ]. Fifth, in case of final double consonants ‘ㅀ’, erroneous pronunciation took the share of 32%. This is regarded as due to the intention to deliver the function and meaning of postpositional particle exactly by combination with inflectional affix ‘-nun’.

이 논문은 현대 국어 겹받침 발음에 적용되는 기본 원리를 제시하고, 현재 혼란양상을 보이고 있는 국어 겹받침 발음의 교육 개선 방향을 제시한 논문이다. 현대국어에서 사용되고 있는 11개의 겹받침 ‘ㄳ, ㄵ, ㄶ, ㄺ, ㄻ, ㄼ, ㄽ, ㄾ, ㄿ, ㅀ, ㅄ’의발음이 어렵게 여겨지거나 교육 현장에서 혼란스럽게 가르쳐지고 있는 이유는 국어겹받침 발음의 원리를 제시하지 않고 가르쳐 온 것이 주요 원인임을 지적하고, 국어음절 발음에서 ‘폐음절 선호 원리’를 겹받침 발음의 기본 원리로 제시해야 함을 밝혔다. 지금까지 겹받침 글자의 앞뒤 순서나, 한글 자모의 순서 등의 기준을 가지고 겹받침 발음을 가르치려고 하고, ‘국어 표준발음법’에서도 복잡한 조항과 [붙임] 등으로여러 예외 조항을 두어 설명하면서 받침 발음 교육의 어려움을 가중시킨 부분이 있었음을 지적했다. 국어 음절의 받침 발음에서 적용되는 원리로 ‘폐음절 선호 원리’를 밝히고, 그에맞추어 국어 표준 발음법을 일부 수정 보완하여 정비하고, 학교 교육에서는 국어 발음 교육의 내용을 정리하고, ‘폐음절 선호 원리’와 같은 원리 중심으로 효과적인 발음교육을 할 것을 제안하였다. 이 논문에서 제안한 내용은 모국어 교육으로서 국어교육뿐만 아니라 외국어로서 한국어 교육 영역에서도 그대로 적용이 가능할 것으로 본다.

The seismic performance of lead-rubber bearings (LRBs) is significantly affected by both the axial force and loading rate they experience. Accurate assessment of LRBs' seismic performance, therefore, requires realistic simulation of these forces and rates, as well as of the response of the isolated structure during seismic events. This study conducted a series of real-time hybrid simulations (RTHS) to evaluate the seismic behavior of LRBs in such conditions. The simulations focused on a two-span continuous bridge isolated by LRBs atop the central pier, exposed to horizontal and vertical ground motions. In the RTHS framework, the LRBs were physically tested in the laboratory, while the remainder of the bridge was numerically modeled. Findings from these simulations indicated that the vertical ground motion had a minimal effect on the lateral response of the bridge when isolated by LRBs.

In order to modeling seismic isolation system such as lead-rubber bearing (LRB), bilinear model is widely used by many researchers. In general, an actual force-displacement relationship for LRB has a smooth hysteretic shape. So, Bouc-Wen model with smooth hysteretic shape represents more accurately actual hysteretic shape than bilinear model. In this study, seismic responses for seismically isolated nuclear power plant (NPP) with LRB modelled by Bouc-Wen and bilinear models are compared with those of NPP without seismic isolation system. To evaluate effect of earthquake characteristics for seismic responses of NPP isolated by LRB, 5 different site class earthquakes distinguished by Geomatrix 3rd Letter Site Classification and artificially generated earthquakes corresponding to standard design spectrum by Reg. Guide 1.60 are used as input earthquakes. From the seismic response results of seismically isolated NPP, it can be observed that maximum displacements of seismic isolation modelled by Bouc-Wen model are larger than those by bilinear model. Seismic responses of NPP with LRB is significantly reduced than those without LRB. This reduction effect for seismic responses of NPP subjected to Site A (rock) earthquakes is larger than that to Site E (soft soil) earthquakes.

In order to increase the seismic safety of nuclear power plant (NPP) structures in high seismicity regions, seismic isolation techniques can be adapted to NPP structures. In this paper, the applicability of multi-step analysis of seismically isolated NPP containment structures with lead-rubber bearings (LRB) is evaluated. The floor response spectrum of NPP containment structures with equivalent linear LRB and nonlinear LRB are compared. In addition, the force-displacement relationships for equivalent linear LRB and nonlinear LRB are compared.

장애인 보조기구 중 목발은 수요가 높을 뿐 아니라 사용빈도가 꾸준히 증가하고 있는 것으로 보고되고 있다. 많은 사람이 필요로 하고, 사용하고 있는 목발에 대한 지속적인 관리의 필요성은 충분히 인식되고 있으나 품질관리는 잘 이루어지지 않고 있는 실정이다. 본 연구에서는 목발 사용의 대표적 문제점인 바닥접촉 고무부분의 마모가 빠르고 미끄럼 사고가 많이 발생한다는 점에 착안하여 시중에 유통 중인 목발을 수거하여 고무 경도 시험과 미끄럼저항 시험을 진행하였다. 시험 결과를 바탕으로 안전한 목발 사용을 위한 목발 고무받침의 기준을 제시하고자 한다.