Effect of Bridge Deck Pavement Stiffness on Vertical Fundamental Frequency of Simply Supported Hollow Slab Bridges

Abstract

The influence of concrete deck pavement on the vertical fundamental frequency of simply supported hollow slab bridges mainly includes the quality and stiffness contributions of the pavement, and this stiffness is divided into longitudinal and transverse stiffness components. The traditional analysis model only considered the quality contribution of the pavement, but the stiffness and vertical fundamental frequency of the structure increased with the same mass. In order to investigate the effects of pavement stiffness on the vertical fundamental frequencies of simply supported hollow slab bridges, three finite element dynamic calculation models were proposed. Through a large number of statistical analyses, the influence of different pavement thicknesses on the vertical fundamental frequencies of simply supported hollow slab bridges with different calculated spans were systematically studied. The results demonstrate that the pavement stiffness has a significant effect on the vertical fundamental frequency of a simply supported hollow slab bridge. The variation rate of the fundamental frequency is between 14% and 29%. It is suggested that the contribution of pavement stiffness should be taken into account when evaluating the fundamental frequency of the hollow slab bridge; otherwise, the mechanical performance of the structure will be overestimated. The influence law and degree of pavement stiffness on the vertical fundamental frequency of the orthogonal and skew hollow slab bridges are different. When building the dynamic calculation model, an orthogonal hollow slab bridge can help establish either the single slab model or the grillage model, and the skew hollow slab bridge should help establish the grillage model.