Dynamic Impact Analysis of Double-Tower Cable-Stayed Maglev Bridges Using a Simple Model

Abstract

The strength and stiffness design of a bridge subject to moving vehicles requires the determination of its dynamic amplification factors (DAFs). This paper presents a simple method for estimating the DAFs of a double-tower multicable-stayed bridge traversed by maglev vehicles. This multicable-stayed bridge with small side spans is idealized as a simply supported Euler beam on an elastic foundation, and the maglev vehicles are simplified as moving uniform forces. A closed-form solution for the dynamic responses of the beam is derived and applied to parametric analysis. The accuracy of the simplified method is first validated by numerical results obtained from precise finite-element (FE) models. The dimensionless parameters governing the DAFs of the beam are then identified: speed parameter, train-bridge length ratio, and elastic support coefficient. Several contour maps against these dimensionless parameters are provided for quick consultation of the DAFs of a bridge in the preliminary design stage. Frequency limits for double-tower cable-stayed bridges are suggested to control the DAFs below a given reasonable value.