scholarly journals Overturning Axis Selection in Curved Box-Girder Bridges with Single-Column Piers

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Guohua Song ◽  
Delu Che ◽  
Minghui Li

This study was conducted to theoretically analyze the overturning axes of curved box-girder bridges with three equal spans and single-column piers per the influence of curvature radius and bearing eccentricity on overturning axis. The theoretical analysis is verified by a model bridge experiment. The results show that overturning axis can be effectively determined according to the connecting line of either bearings at the central piers or outmost bearings at abutments as influenced by curvature radius and bearing eccentricity. In other words, no bearings are outside of overturning axis. All the bearings but the two on the overturning axis are located on the inner side of the axis. For curved bridges with multispans and single-column or double-column piers, the overturning axis is characterized by the connecting line of the two adjacent outmost bearings.

1995 ◽  
Vol 22 (1) ◽  
pp. 93-105 ◽  
Author(s):  
M. S. Cheung ◽  
S. H. C. Foo

Because of their excellent torsional capacity, box girders are used extensively in modern bridge construction having curved alignments. Applications of most design codes have been limited to bridges where the radius of curvature is much greater than the span length and cross-sectional dimensions. To meet the practical requirements arising during the design process, simple design methods are needed for curved bridges. This paper presents the results of a parametric study on the relative behaviour of curved and straight box-girder bridges and on the development of a simplified design method for the combined longitudinal moment of curved bridges. The combined moment includes the effects of flexure, torsion, and distortion. Three simply supported concrete-steel composite bridge models, including single-cell, twin-cell, and three-cell box girders and subjected to loadings as specified in the Ontario Highway Bridge Design Code, were analyzed using the finite strip method. The parameters considered in the study include types of cross section; types, locations, and magnitudes of loads; span lengths; and radius of curvature. Preliminary analysis of the results suggests that the behaviour of horizontally curved box-girder bridges is dependent on a variety of parameters, but most importantly on the span-to-radius ratio. Empirical relationships for combined longitudinal moment between curved and straight box-girder bridges are also proposed. Key words: bridge, curved, composite, design, finite strip.


Author(s):  
V. Verma ◽  
K. Nallasivam

Purpose: Curved box-girder bridges offers an excellent solution to the problems associated with traffic congestion. However, owing to their complex geometry, they are subjected to shear lag, torsional warping and cross-sectional distortion, which must be assessed in their study and design. Furthermore, the dynamic behaviour of curved bridges adds to the complexity of the issue, emphasizing the importance of studying free vibration. The purpose of this study is to numerically model the concrete curved box-girder bridge considering torsional warping, distortion and distortional warping effects and to identify key parameters that influence the free vibration response of the box-girder bridge by validating it with experimental and analytical studies. Design/methodology/approach: The concrete bridge is numerically modelled by means of computationally effective thin-walled box-beam finite elements that consider torsional warping, distortion and distortional warping, which are prominent features of thinwalled box-girders. The free vibration analysis of the concrete curved box-girder bridge is performed by developing a finite element based MATLAB program. Findings: The identification of critical parameters that influence the free vibration behaviour of curved thin-walled concrete box-girder bridges is one of the main findings of the study. Each parameter and its effect has been extensively discussed. Research limitations/implications: The study limits for the preliminary design phase of thin-walled box-girder bridge decks, where a complete three-dimensional finite element analysis is unnecessary. The current approach can be extended to future research using a different method, such as finite element grilling technique on multi-span curved bridges having unequal span.


2011 ◽  
Vol 255-260 ◽  
pp. 926-930 ◽  
Author(s):  
Xin Yi Huang ◽  
Wei Dong Zhuo ◽  
Shang Guan Ping

The impact factors for vehicle load were ever characterized by varied parameters among different countries, and it is now commonly described by the fundamental frequency of the first bending mode for straightened bridges, but there are still no computation formulae proposed for concrete curved bridges. Massive vehicle-bridge interaction analysises are carried out on concrete curved box girder bridges with different span length, curvature radius, section type, span number and boundary conditon, using a validated numerical method. Based on the obtained results, the impact factors for varied effects are discussed, as well as their correlation with parameters of central radius, ratio of bending to torsional rigidity, integral impact coefficient and the fundamental frequency of vertical bending mode. It is indicated that, the impact factor of interal forces, deflection and reaction force are minus correlated with the discussed parameters except for ratio of bending rigidity to torsional rigidity. The impact factors are most closely correlated with the fundamental frequency of vertical bending mode, so it is best suited to characterize the change of impact factors.


Structures ◽  
2021 ◽  
Vol 30 ◽  
pp. 1097-1108
Author(s):  
Zhi-Qi He ◽  
Yonghui Li ◽  
Tian Xu ◽  
Zhao Liu ◽  
Zhongguo John Ma

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