PARAMETRIC STUDY OF THE EFFECT OF CROSS-FRAMES AND LATERAL BRACINGS ON FREE VIBRATION RESPONSE OF HORIZONTALLY CURVED I-GIRDER BRIDGES | ||||
| JES. Journal of Engineering Sciences | ||||
| Article 2, Volume 36, No 2, March and April 2008, Page 295-312 PDF (654.65 K) | ||||
| Document Type: Research Paper | ||||
| DOI: 10.21608/jesaun.2008.115622 | ||||
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| Author | ||||
| Mohamed Abdel-Basset Abdo | ||||
| Civil Engineering Department, Faculty of Engineering, Assiut University, Assiut, Egypt | ||||
| Abstract | ||||
| This study is concerned with parametric study of the effect of cross frames and bottom lateral bracings on the free vibration response of steel Igirder bridges during the time of construction using finite element technique. The study includes an important factor of free vibration response which is the frequency. The first ten mode frequencies are studied for each model. Based on the numerical results, it is shown that increasing the cross frame stiffness has slight effect on the frequency of curved I-girder systems and does not necessary lead to an increase in system frequencies. However, it is recommended to use maximum slenderness ratio, max = 140 since it gives optimum frequencies for curved I-girder systems for all degrees of curvature. Also, it is found that the suitable distance between cross frames in curved systems ranges from 5 m to 3 m. On the other hand, an increase in flange width has a significant effect on normalized frequency and as the bottom flange increases the frequency is increased for all degrees of curvature. Moreover, it is found that the increase in number of girders or girder spacing has a negligible effect on the free vibration response of curved Igirder bridges of low degree of curvature. However, their effect on frequencies is more pronounced in girders of high degrees of curvature. The presence of lateral bottom bracings has great effect on the frequencies of lower modes. So, existence of lateral bracings of any type is so useful for free vibration response of curved systems during construction. | ||||
| Keywords | ||||
| Parametric study; cross frames; lateral bracings; free vibration response; horizontally curved I-girder bridges | ||||
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