EFFECT OF BOTTOM LATERAL BRACINGS ON THE BEHAVIOUR OF COMPOSITE STEEL-CONCRETE BRIDGES CURVED IN PLAN | ||||
| JES. Journal of Engineering Sciences | ||||
| Article 6, Volume 34, No 5, September and October 2006, Page 1417-1432 PDF (239.27 K) | ||||
| Document Type: Research Paper | ||||
| DOI: 10.21608/jesaun.2006.111061 | ||||
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| Author | ||||
| Mohamed Abdel-Basset Abdo* | ||||
| Lecturer, Civil Engineering Department, Faculty of Engineering, Assiut University, Assiut, Egypt. | ||||
| Abstract | ||||
| The present study is concerned with the effect of the presence of bottom lateral bracing systems on the behaviour of horizontally curved composite bridges. A careful numerical study is carried out by using the finite element method in the elastic range of loading. Shoring is assumed to be used during construction and the system is provided with cross frames. The present study includes tangential stresses, warping-tobending stress ratio, vertical displacements and radial displacements through the inner edge, middle and outer edge of the bottom flange along the span of the critical outside girder. Also, the maximum axial forces in bracing members for the most effective type are studied. Based on the numerical results, it is shown that the presence of bottom lateral bracings in curved composite bridge results in significant reduction of not only bending and warping stresses but also vertical and radial displacements as well as torsional angle of bottom flanges. The reduction in stresses of curved bridges due to the presence of lateral bracings may exceed 25% of the stresses obtained using cross frames only and the reduction in stresses is more pronounced for small radii of curvatures. So, lateral bracings can be used effectively in strengthening of existing bridges or to decrease the cross sectional area of new curved composite bridges. Also, the results show that the most effective pattern of lateral bracings is that which consists of X-bracings in all bays. However, the pattern of bracing which consists of X-bracings in end panels only give the greatest stresses and displacements of all of the studied reinforcement patterns. Furthermore, for high degree of curvature, the stresses in bracing members should be checked since they are subjected to large stresses due to curvature in addition to those due to wind loads. | ||||
| Keywords | ||||
| Lateral bracings; composite steel-concrete girders; degree of curvature; warping and bending stresses; displacements | ||||
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