Dynamic evaluation of girder cross-sectional shapes of bridges

The purpose of this study is to assess the influence of girder cross-sectional shapes that is using in the design of prestressed concrete bridge girders and steel bridge girders on the dynamic parameters such as natural vibration frequency, moving load vibration frequency, dynamic displacement in three dimensions, dynamic acceleration in three dimensions, and dynamic moment, and dynamic stresses. The results of the dynamic analysis show that model No.6 (box girder with external web curved) has a value of natural vibration frequency (13.38Hz) is more than the maximum value of moving load vibration frequency (13.25Hz) within model No.6 (box girder with external web curved model). This mean, model No.6 has enough stiffness, elasticity, and bearing capacity. Model No.7 (box girder with external web vertical model) has the maximum value of natural vibration frequency (13.42Hz) which is more than the all values of moving load vibration frequency of others models, indicating that model No.7 has a higher value of bearing capacity and elasticity. For other dynamic parameters, the box girders shapes appear minimum values of dynamic displacement, dynamic acceleration, dynamic moment, and dynamic tensile stress. Therefore, the box girders shapes are more suitable to design bridges structures.