Nguyen Van, Ban
(Dept. of Civil and Environmental Engineering, Korea Univ.)
,
Kim, Sung-Nam
(Dept. of Civil and Environmental Engineering, Korea Univ.)
,
Kim, Seung-Jun
(Dept. of Civil and Environmental Engineering, Korea Univ.)
,
Kang, Young-Jong
(Dept. of Civil and Environmental Engineering, Korea Univ.)
최근에 빠른 발전을 이루고 있기는 하나, 하중 저항 계수나 미관효과 면에서 박스 거더를 고속도로 분야에 폭넓게 사용하고 있는 실정이다. 최근의 박스 거더 설계를 기반으로 살펴보면 뒤틀림 하중은 그다지 고려되지 않았다. 특히 직선교에서는 뒤틀림 하중의 효과가 작지만 곡선에서는 어떻게 작용하는지 조차 알려진 것이 없었다. 그러한 이유에서 이 연구는 뒤틀림 거동에 미치는 주요한 변수들에 대해 다루었다. 그리고 유한요소법을 사용하는 Dabrowski formula를 바탕으로 하여 다양한 변수의 교량에 대해 연구하였다. 이 연구에서는 다음과 같은 변수들이 사용된다. : 지간장, 곡률반경, 단면높이, 단면폭, 그리고 내부단면각(internal section angle) 연구된 결과로부터 적당한 초기 기하형상에 대한 변수들을 구할 수 있을 것이다.
최근에 빠른 발전을 이루고 있기는 하나, 하중 저항 계수나 미관효과 면에서 박스 거더를 고속도로 분야에 폭넓게 사용하고 있는 실정이다. 최근의 박스 거더 설계를 기반으로 살펴보면 뒤틀림 하중은 그다지 고려되지 않았다. 특히 직선교에서는 뒤틀림 하중의 효과가 작지만 곡선에서는 어떻게 작용하는지 조차 알려진 것이 없었다. 그러한 이유에서 이 연구는 뒤틀림 거동에 미치는 주요한 변수들에 대해 다루었다. 그리고 유한요소법을 사용하는 Dabrowski formula를 바탕으로 하여 다양한 변수의 교량에 대해 연구하였다. 이 연구에서는 다음과 같은 변수들이 사용된다. : 지간장, 곡률반경, 단면높이, 단면폭, 그리고 내부단면각(internal section angle) 연구된 결과로부터 적당한 초기 기하형상에 대한 변수들을 구할 수 있을 것이다.
Although just developed in recent years, curved box girder has widely used in modern highway system due to their load resistance capacity as well as aesthetic considerations. According to recent literature reviews on curved box girder designs, distortional load was not considered as much as it deser...
Although just developed in recent years, curved box girder has widely used in modern highway system due to their load resistance capacity as well as aesthetic considerations. According to recent literature reviews on curved box girder designs, distortional load was not considered as much as it deserves to be. In practice, the effect of distortional force is very small in straight bridge systems but yet unknown how it is in curved bridge systems. For the reason, this paper will show an extensive parametric study on distortional behavior. Based on Dabrowski formulas, using finite element method, various bridges were investigated. In this study, following parameters will be included: span length, curvature radius, section height, section width, and internal section angle (web slope). From the obtained results, some initial geometric parameters are proposed for curved box girder bridges.
Although just developed in recent years, curved box girder has widely used in modern highway system due to their load resistance capacity as well as aesthetic considerations. According to recent literature reviews on curved box girder designs, distortional load was not considered as much as it deserves to be. In practice, the effect of distortional force is very small in straight bridge systems but yet unknown how it is in curved bridge systems. For the reason, this paper will show an extensive parametric study on distortional behavior. Based on Dabrowski formulas, using finite element method, various bridges were investigated. In this study, following parameters will be included: span length, curvature radius, section height, section width, and internal section angle (web slope). From the obtained results, some initial geometric parameters are proposed for curved box girder bridges.
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문제 정의
cross section; they also provide an aesthetic appearance to the bridge. In this study, we will investigate the effects of this angle on distortional behavior. According to Hall and Yoo (1999) the web slope of plane normal to the flange is recommended not to exceed 1 to 4, that means 0 should not smaller than 75°.
The purpose of this study is to increase the knowledge on distortional behavior of structures. According to over 200 bridges analyzed to investigate the influence of numerous parameters on distortional behavior in curved girder bridge, this study has upgraded and verified Dabrowski formulas of normal stress deposition.
가설 설정
-The internal angle has significant effect on distortional behavior in curved box girder bridge. The trapezoidal section should be used in curved box girder bridges, and it is suggested to use with the internal section angle of 75 degree
-The ratio of top flange width to section height has a direct proportional relationship to distortional behavior of structures. It is suggested to increases section height and reduce flange width under control by the limits of the ratio of distortional warping normal stress to bending normal stress to bending normal stress and transverse bending normal stress.
Usually in practical designs, the height of cross-section will be firstly selected basing on span length and the type of bridge. In this study we consider to a single span bridge, base on bending behavior the height of cross-section is suggested as 1/16시/18 times of the span length. And the ratio of width to height of section is suggested from LI~1.
제안 방법
The purpose of this study is to increase the knowledge on distortional behavior of structures. According to over 200 bridges analyzed to investigate the influence of numerous parameters on distortional behavior in curved girder bridge, this study has upgraded and verified Dabrowski formulas of normal stress deposition. The notice when applying the formulas is the method to calculate toque moment mTs this moment should be calculated in considering two terms which are related to eccentric effect and the additional curvature effect.
대상 데이터
A more commonly specification related to curved girder, AASHTO Guide Specifications for Horizontally Curved Steel Girder Highway Bridges (2003) had suggested this angle should be smaller than 17 degrees. The bridges were checked for in investigation have four different span lengths 30; 40; 50 and 60 meters. The horizontal radius of span centerline is changed among four values 60; 80; 100 and 120 meters.
이론/모형
The finite element analysis program LU SAS was used to simulated three-dimensionl modeling of bridges. A four-node shell element QSI4, with six degrees of freedom (three displacements and three rotations) at each node was used to model the girders.
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