A method of spline function for dynamic analysis in suspension bridges

A method of analysis is presented for the free vibration of straight suspension bridges with a long span, stiffened by plate girder and box beam (or truss). The method takes combining spline finite element with spline finite strip to investigate the vertical and torsional vibration as well as their coupling. It uses variational principle to obtain dynamic characteristics matrices for solving the eigenproblem. On this basis, a spline model of the whole bridge corresponding to the tunnel test is established for flutter analysis. The spline expression of aerodynamic force on flutter is derived and the fininal eigenvalue solution will produce the desired flutter frequency and critical velocity of wind. Numerical examples are shown to demonstrate the applicability of the method.