Analytical and numerical study on free vertical vibration of smear-flexible suspension bridges

This study develops an analytical and numerical method for free vertical vi bration of suspension bridges including shear deformation and rotary inerti a. Under the assumption that the Vertical displacement of the main cable is identical to that of the stiffening girder, the differential equation of m otion containing three new terms are derived based on Timoshenko's beam-col umn theory. The general analytical method for determining natural frequenci es and mode shapes of hinged- and continuous-suspension bridges are present ed. Special consideration is given is evaluating the natural frequency of s imply supported three-span suspension bridges. For finite element analysis, the suspension bridge element is developed by using Hermitian polynomials considering shear effects. The full truss model, in which both cable and tr uss girder is modelled by a truss element, is used in order to investigate the accuracy of the presented suspension bridge theory. Numerical examples are provided to illustrate the applicability and effectiveness of the prese nt analytical and numerical method. (C) 2000 Academic Press.