• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.402-404
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• 2003

In case to look at considering affects of skew angles into the curved bridges, this study mainly focalized to compare and analyze of the influence of skew angles to curved bridges along with analysis of the behavior of entire construction in accordance with changes of skew angles and curvature. With explanation of macroscophic behavior of curved bridges with skew angles through this study, it is mostly to grasp with characteristics and structural weaknesses of skew curved bridges compared with straight skew bridges.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.380-387
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• 2005

Little has been understood about the seismic behavior of curved bridges due to the different structural characteristics compared to straight bridges. In this study, a simple numerical model, widely used for seismic analysis, is modified for a more realistic estimation of the seismic behavior. The seismic response of curved bridges obtained with the modified simple numerical model was compared with the result using a more sophisticated model to verify the feasibility. Seismic analyses were performed on three-span continuous curved bridges, which is a structural system widely used in highway structures. Numerical model of the three-span continuous curved bridges were subjected to seismic loads in diverse directions. From the result of the analysis. it was found that the direction of the seismic load have significant effect of the seismic behavior of curved bridges when the central angle exceeds 90 degrees.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.381-387
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• 2002

Curved bridges are composed of curved members which have certain curvatures, comparing to straight bridges. Therefore, their behavior is quite different from one of the straight bridges, mainly due to the geometric characteristics of the curved bridges. In this paper, the curved bridges consisted of the single box-girder span are investigated to study the effects of negative reaction forces. The parameters considered in this study are span lengths, angles of curvature, and the number of shoes. Midas/civil computer program was used for the analysis of the curved bridges. The analysis results show that negative reaction forces are not created with one shoe installed. When two shoes are provided, on the other hands, the uplift forces are developed at the inside shoe. It is also concluded that the increasing ratio of negative reaction forces becomes larger, as the angles of curvature increase, and the elongation of span lengths turns out to increase the magnitudes of the uplift forces.

• Earthquakes and Structures
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• v.10 no.4
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• pp.789-810
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• 2016

Reinforced concrete (RC) bridges with both skew and curvature are pretty common in areas with complex terrains. Existing studies have shown skewed and/or curved bridges exhibit more complicated seismic performance than straight bridges, and yet related seismic risk studies are still rare. These bridges deserve more studies in low-to-moderate seismic regions than those in seismic-prone areas. This is because for bridges with irregular and complex geometric designs, comprehensive seismic analysis is not always required and little knowledge about actual seismic risks for these bridges in low-to-moderate regions is available. To provide more insightful understanding of the seismic risks and the impact from the geometric configurations, analytical fragility studies are carried out on four typical bridge designs with different geometric configurations (i.e., straight, curved, skewed, skewed and curved) in the mountain west region of the United States. The results show the curved and skewed geometries can considerably affect the bridge seismic fragility in a complex manner, underscoring the importance of conducting detailed seismic risk assessment of skewed and curved bridges in low-to-moderate seismic regions.

• Structural Engineering and Mechanics
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• v.78 no.3
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• pp.255-267
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• 2021

The analysis of simply supported single-cell skew-curved reinforced concrete (RC) box-girder bridges is carried out using a finite element based CsiBridge software. The behaviour of skew-curved box-girder bridges can not be anticipated simply by superimposing the individual effects of skewness and curvature, so it becomes important to examine the behaviour of such bridges considering the combined effects of skewness and curvature. A comprehensive parametric study is performed wherein the combined influence of the skew and curve angles is considered to determine the maximum bending moment, maximum shear force, maximum torsional moment and maximum vertical deflection of the bridge girders. The skew angle is varied from 0° to 60° at an interval of 10°, and the curve angle is varied from 0° to 60° at an interval of 12°. The scantly available literature on such bridges focuses mainly on the analysis of skew-curved bridges under dead and point loads. But, the effects of actual loadings may be different, thus, it is considered in the present study. It is found that the performance of these bridges having more curvature can be improved by introducing the skewness. Finally, several equations are deduced in the non-dimensional form for estimating the forces and deflection in the girders of simply supported skew-curved RC box-girder bridges, based upon the results of the straight one. The developed equations may be helpful to the designers in proportioning, analysing, and designing such bridges, as the correlation coefficient is about 0.99.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.3 s.18
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• pp.11-21
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• 2005

This study is performed to understand complex behavior and to investigate the rational analysis methods for seismic design of the curved bridges. To analyze the curved bridges for the seismic loadings, it is used that the finite element analysis program has the 7-dof curved beam and straight beam element. The free vibration characteristics of the curved bridges are compared with the straight bridges that have span length same as the average arc length of inside and outside girder of those. For the same case, the dynamic behavior is compared under seismic loadings. It is found that regular bridges classified by AASHTO are analyzed as if those were straight. To investigate the dynamic behavior of general curved bridges under seismic loading, the seismic loading directions and the subtended angle of curved bridges are varied.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.567-572
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• 2008

This paper's purpose is to improve determining of the critical response of curved bridge to multi-component seismic motion. There are several methods to combine responses by multi-component excitation response, 30%, 40% rules and square-root-of-sum (SRSS). These combination rules determine same value of critical response in straight bridges. However, each method has critical response value of different magnitude in curved bridges. Thus a study about critical response of curved bridges is required. This paper presents comparison critical responses value as each combination rule, 30%, 40% rules and SRSS on curved bridges with the different radiuses of curvature. This study was carried out by response spectrum analysis of OO IC steel box girder bridge using SAP2000. It is concluded as follows: 1) In curved bridges, 30% and 40% rules tend to underestimate the critical response relatively to SRSS. 2) When bridges have smaller radiuses than 100m, difference between SRSS and 30% or 40% rules let run errors up as radiuses of curvature decreased.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.955-963
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• 2006

As the geometrical characteristic of the curved bridge, the seismic response of curved bridges are different from straight bridges. This study analyzed the seismic response of the curved bridges considering diverse factors such as radius of curvature, direction of seismic load and support condition. The improved simple modeling of the curved bridge for seismic analysis is proposed, and it is compared with the detail modeling in order to verify the simple modeling. Three simply supported curved bridges and six 3-span continuous bridges are selected for seismic analysis. The behavior of curved bridges are evaluated in terms of the displacement and the force at supports and piers under seismic load applied in various directions. The results of this study show that upward reaction force may appear in simply supported curved bridge under seismic load. And continuous curved bridges are affected by the direction of the seismic load.

• Journal of Korean Society of Steel Construction
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• v.17 no.5 s.78
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• pp.511-518
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• 2005

The behavior of steel curved bridges is more complicated than straight bridges, thus the analysis, design and construction process of curved bridges require much more attention. In design of curved bridges, the grillage analysis using general structural analysis program or special program is mainly used. Comparative study in coherence between these analytical results and actual behavior of curved bridges has been rarely conducted. To study the behaviour of curved bridges and verify the current design method, field measurements and analyses using general structural analysis program and 3-D refined analysis program were carried out for simple and continuous bridges in this study. The study focused on the behavior of curved steel bridges during construction. Measured and analytical results had quantitative difference mutually, but there were qualitatively similar. Stress variations in transverse direction of flange were observed and grillage analysis models yielded more conservative values than 3-D refined analysis models.

• Structural Monitoring and Maintenance
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• v.7 no.4
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• pp.367-392
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• 2020

The specific characteristics of near-field earthquake records can lead to different dynamic responses of bridges compared to far-field records. However, the effect of near-field strong ground motion has often been neglected in the seismic performance assessment of the bridges. Furthermore, damage to horizontally curved multi-frame RC box-girder bridges in the past earthquakes has intensified the potential of seismic vulnerability of these structures due to their distinctive dynamic behavior. Based on the nonlinear time history analyses in OpenSEES, this article, assesses the effects of near-field versus far-field earthquakes on the seismic performance of horizontally curved multi-frame RC box-girder bridges by accounting the vertical component of the earthquake records. Analytical seismic fragility curves have been derived thru considering uncertainties in the earthquake records, material and geometric properties of bridges. The findings indicate that near-field effects reasonably increase the seismic vulnerability in this bridge sub-class. The results pave the way for future regional risk assessments regarding the importance of either including or excluding near-field effects on the seismic performance of horizontally curved bridges.