Performance assessment of channel beam bridges with hollow track bed decks

Abstract

This paper uses experimental and numerical methods to investigate the structural performance of prestressed concrete channel beam bridges with hollow track-bed decks. In the experimental program, two down-scale hollow deck channel beam specimens, including a longitudinal beam specimen and a lateral beam specimen, maintaining the features of a recently constructed channel beam railway bridge in China, were designed, fabricated and loaded to failure. The failure pattern, load-deflection curves, and strain history of the hollow deck channel beams under flexural loads were presented and discussed. Experimental results show that the channel beam with a serrated-shaped hollow concrete deck had large bending stiffness and ultimate resistance, which enables a favorable safety margin for engineering application. The usage of a hollow concrete deck significantly improved the loading-bearing efficiency and ductility of the structure. In the numerical simulation, a nonlinear finite element (FE) model was established for the channel beams, and a comparison between the experimental and numerical modeling results was conducted to assess the accuracy of the model. An extensive parametric study incorporating a series of FE models was performed to generate further numerical data covering a broad range of prestressing and geometric parameters. The numerical results manifest that the cracking performance and bending stiffness of the hollow deck channel beam were improved by enhancing of prestressing degree and depth-to-span ratio, and an optimized girder-to-deck corner angle is significant for guaranteeing the cracking performance of the channel beam structure. Furthermore, an analytical model to determine the mechanical response of the hollow deck channel beam bridge under permanent and track loads is recommended. The outcomes of this study provide a reference for the future design and application of the hollow deck channel beam bridges.