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Abstract The free vibration characteristics, natural frequency and mode shapes, as well as the dynamic response to moving load of simply supp¬orted, continuous two span and three span cantilever bridges are studied in this thesis. The bridges are assumed to act as elastic beams. ducted by means of the finite element technique. The analysis is con¬The mass of the structure is assumed consistent since the rotational degree of freedom at each node is considered. Moreover, a simple method for the load treatment has been used to represent the load at each degree of freedom with a method which is general, easy to use and suitable for the numerical solution of the prohlem of moving load on bridges The finite element method has been developed to treat the case of dynamic analysis of bridges with intermediate hinges. This treatment was accomplished through modifying the elements of the stiffness mat- rix for the segments which have a hinged end. The results showed, that the determination of natural frequencies and mode shapes agree with the previous methods. In general, when the speed of a vehicle Increases, the dynamic load fac¬tor me r eases. |