• Structural Engineering and Mechanics
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• 제88권1호
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• pp.53-65
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• 2023

With the gradual implementation of long-span suspension bridges into high-speed railway operations, the main beam's bending stiffness contribution to the live load response permanently grows. Since another critical control parameter of railway suspension bridges is the beam-end rotation angle, it should not be ignored by treating the main beam deflection as the only deformation response. To this end, the current study refines the existing method of the main cable shape and simply supported beam bending moment analogy. The bending stiffness of the main beam is considered, and the main beam's analytical expressions of deflection and rotation angle in the whole span are obtained using the cable-beam deformation coordination relationship. Taking a railway suspension bridge as an example, the effectiveness and accuracy of the proposed analytical method are verified by the finite element method (FEM). Comparison of the results by FEM and the analytical method ignoring the main beam stiffness revealed that the bending stiffness of the main beam strongly contributed to the live load response. Under the same live load, as the main beam stiffness increases, the overall deformation of the structure decreases, and the reduction is particularly noticeable at locations with original larger deformations. When the main beam stiffness is increased to a certain extent, the stiffening effect is no longer pronounced.

• 한국강구조학회 논문집
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• 제29권6호
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• pp.467-477
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• 2017

현행 국내 교량 설계기준의 활하중 모형인 KL-510의 하중 효과를 실측된 통행자료로부터 통계적으로 추정한 트럭의 연행효과 및 국내외 관련 설계기준이 하중모형과 비교한다. 과적단속 전후에 고속도로에서 측정된 트럭의 중량 자료를 이용하여 설계기준의 활하중 모형 결정과 동일한 과정을 따라서 트럭 중량을 산정하여 그 하중효과를 KL-510과 비교하였다. KL-510은 운행제한중량을 초과하는 트럭을 일부 포함하는 자료로부터 추정한 트럭의 연행에 의한 하중효과와 매우 부합하는 결과를 보였다. KL-510은 미국 AASHTO LRFD의 활하중 모형과 일관성 있는 결과를 주며, 기존 하중 모형인 DB-24보다 하중효과의 비율이 균일하였다. 이 연구의 결과로 가상의 하중 모형인 KL-510에 해당하는 실제 트럭의 조합을 구성하였으며, 향후 공용중인 교량의 평가와 허가차량의 하중계수 보정에 적용할 수 있다.

• 대한토목학회논문집
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• 제26권3A호
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• pp.539-546
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• 2006

국내 LRFD 도로교설계규정을 정립하기 위한 기초 자료를 제공하기 위하여 단경간 플레이트 거더 및 박스 거더 합성단면을 하중저항계수설계법으로 설계하고 설계된 단면의 휨에 대한 신뢰도해석을 수행하였다. 신뢰도해석에서 휨저항강도는 최근 국내에서 생산된 16,000여 구조용 강재 표본의 항복강도 통계적 특성이 반영된 강합성단면의 휨저항강도 통계를 이용하였다. 활하중에 의한 작용모멘트 통계는 고정된 값을 사용하지 않고 편심계수 0.95-1.05를, 변동계수는 0.15-0.25로 가정하였다. 강거더 자중, 콘크리트 바닥판 자중, 포장면 자중 등에 의한 고정하중 모멘트 통계 값은 AASHTO 보정자료를 사용하였다. Rackwitz-Fiessler 법으로 신뢰도해석을 수행하고 지간별, 강거더 형식별, 활하중 모멘트의 불확실성 정도별로 신뢰도지수 계산 결과를 제시하였다.

• Steel and Composite Structures
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• 제28권3호
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• pp.363-380
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• 2018

This paper presented an integral design procedure for demountable bolted composite frames with semi-rigid joints. Moment-rotation relationships of beam-to-column joints were predicted with analytical models aiming to provide accurate and reliable analytical solutions. Among this, initial stiffness of beam-to-column joints was derived on the basis of Timoshenko's plate theory, and moment capacity was derived in accordance with Eurocodes. The predictions were validated with relevant test results prior to further applications. Frame analysis was conducted by using Abaqus software with material and geometrical nonlinearity considered. Variable lateral loads incorporating wind actions and earthquake actions in accordance with Australian Standards were adopted to evaluate the flexural behaviour of the composite frames. Strength and serviceability limit state criteria were utilized to verify configurations of designed models. A wide range of frames with the varied number of storeys and bays were thereafter programmed to ascertain bending moment envelopes under various load combinations. The analytical results suggest that the proposed approach is capable of predicting the moment-rotation performance of the semi-rigid joints reasonably well. Outcomes of the frame analysis indicate that the load combination with dead loads and live loads only leads to maximum sagging and hogging moment magnitudes in beams. As for lateral loads, wind actions are more crucial to dominate the design of the demountable composite frames than earthquake actions. No hogging moment reversal is expected in the composite beams given that the frames are designed properly. The proposed analysis procedure is demonstrated to be a simple and efficient method, which can be applied into engineering practice.

• 한국강구조학회 논문집
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• 제18권3호
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• pp.373-383
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• 2006

거푸집용 데크 플레이트를 사용하는 일방향 슬래브는 구조형식상 4변을 강성이 다른 철골보로 지지된 플레이트 요소이지만 일반실무에서는 철근콘크리트구조 설계기준을 적용하여 일정폭을 가진 연속보로 간주하여 근사적인 해석법을 사용하고 있다. 거푸집용 비합성데크 일방향 슬래브를 지지하고 있는 철골보는 지지형태 및 위치에 따라 서로 다른 처짐이 발생되는 탄성지점으로서 지점별로 발생되는 휨모멘트 값큰 차이가 난다. 따라서, 본 연구는 단부의 부동처짐 효과를 고려한 근사해석법상의 휨모멘트 계수를 합리적으로 산정하기 위하여 다양한 해 석모델을 가정하였으며, 해석상의 변수로는 고정하중에 대한 활하중의 비율, 스팬별 활하중의 배열(패턴재하) 및 스팬길이를 고려하였다. 또한 해석방법으로 3차원 플레이트 유한요소해석, 이차원 탄성지점해석, 이차원 무한강성지점해석, 설계기준상의 근사해석을 각각 적용하여 결과값을 비교 분석하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제9권3호
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• pp.151-160
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• 2005

현재의 교량설계기준에서는 연속거더교량에 대한 활하중 분배계수 규정에 대해 명확한 언급이 되어있지 않다. 따라서 이 논문의 목적은 단순교에 사용되는 시방서 규정 활하중 분배계수가 연속거더교에도 적용이 가능한지를 유한요소해석에 의해 검증하는 것이다. 연속거더교에 대한 활하중 분배의 영향을 검증하기 위해 5개의 공용중인 연속교에 대한 유한요소해석을 실행하였으며 그 결과 연속교에서 정모멘트 구역과 부모멘트 구역에서 활하중의 분배 형태는 매우 비슷하다는 결론을 내릴 수 있었다. 또한 처짐값의 비교에서 얻어진 활하중의 분배와 변형율에 기본한 활하중의 분배 양상의 차이가 거의 없는 것으로 나타났다. 해석 결과 현재 사용되고 있는 설계기준의 활하중 분배에 대한 규정은 연속거더교에 대해 매우 보수적이라고 판단된다.

• Steel and Composite Structures
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• 제31권4호
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• pp.373-385
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• 2019

This paper presents a useful in-plane structural analysis of low-rise blind-bolted composite frames with semi-rigid joints. Analytical models were used to predict the moment-rotation relationship of the composite beam-to-column flush endplate joints that produced accurate and reliable results. The comparisons of the analytical model with test results in terms of the moment-rotation response verified the robustness and reliability of the model. Abaqus software was adopted to conduct frame analysis considering the material and geometrical non-linearities. The flexural behaviour of the composite frames was studied by applying the lateral loads incorporating wind and earthquake actions according to the Australian standards. A wide variety of frames with a varied number of bays and storeys was analysed to determine the bending moment envelopes under different load combinations. The design models were finalized that met the strength and serviceability limit state criteria. The results from the frame analysis suggest that among lateral loads, wind loads are more critical in Australia as compared to the earthquake loads. However, gravity loads alone govern the design as maximum sagging and hogging moments in the frames are produced as a result of the load combination with dead and live loads alone. This study provides a preliminary analysis and general understanding of the behaviour of low rise, semi-continuous frames subjected to lateral load characteristics of wind and earthquake conditions in Australia that can be applied in engineering practice.

• 콘크리트학회논문집
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• 제16권5호
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• pp.709-717
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• 2004

The existing AASHTO Standard Specification have some inadequacies in expressing wheel load distribution of bridge which has specific shape of curved bridge instead of straight bridge. Thus, this research presented the finite element analysis and modelling technique of prestressed concrete girder bridge having curved slab and the expression of wheel load distribution was suggested as the ratio of bending moment utilizing the result of finite element analysis of prestressed concrete girder bridge having cowed slab. The considered parameter of girder distribution expression is the curvature of slab, span length, girder space, cross beam space and number of lanes. Though the suggested girder distribution expression is generally underestimated below AASHTO Standard Specification, once the curvature of slab increases, the suggested expression gets larger than AASHTO LRFD Standard Specification.

• 산업기술연구
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• 제2권
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• pp.3-11
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• 1982

Reliability analysis methods have been employed in this study to determine the safety index ${\beta}$ for flexure associated with reinforced concrete designs that are in accordance with current USD code of Korea. In reliability analysis, the mean first-order second-moment methods are employed. The following specific conclusions can be drawn from this study; 1) Levels of safety for reinforced concrete design, measured by ${\beta}$, vary from 2.8 to 3.8 in flexure depending on the limit state, the ratio of live load to dead load and the uncertainties. 2) Target reliability ${\beta}$ associated with reinforced concrete beams in flexure is assumed to be 3.5~4.0 in Korea. 3) Load factors and resistance factors in flexure associated with the current provisions contained in USD code generally seem to be too high. The writer concluded the factors as following; ${\phi}=0.8,\;{\gamma}_D=1.1\;{\gamma}_L=1.75$.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.425-432
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• 2004

In this paper, the results of the numerical analysis for the minimum depth of soil cover have been compared with those of currently suggested codes. Based on this comparison, the minimum depth of soil cover for the structures with long spans was suggested. Results showed that the actual depth of the soil cover required against soil failure over a circular and low-profile arch structure does not vary significantly with the size of the span and for the circular structure, the minimum depth of the soil cover was about 1.5m, and for the low-profile arch structures, below about 1.6m. And the previously established code in which the minimum depth of soil cover is defined to linearly increase with the increase in the span (CHBDC, 2001) was very conservative. For the structure with the relieving slab, the maximum live load thrust was reduced by about 36 percent and the maximum moment about 81 percent. The numerical analysis gave more conservative estimation of the live-load thrusts than the other design methods.